KR100764339B1 - Supercooling apparatus - Google Patents

Abstract

The subcooling unit 200 has a refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10. When the subcooling compressor 221 is operated, the subcooling refrigerant circulates in the subcooling refrigerant circuit 220 and the freezing circulation is performed to cool the refrigerant in the refrigerating device 10 flowing through the refrigerant passage 205. The detection value of the suction pressure sensor 234 or the refrigerant temperature sensor 236 is input to the controller 240 of the subcooling unit 200. The controller 240 controls the operation of the subcooling compressor 221 based on the information obtained in the subcooling unit 200 using the input signals from the sensors 234 and 236. Thereby, the operation of the subcooling compressor 221 can be controlled without the need for signal passing between the refrigeration apparatus to be installed.

Description

Supercooling Unit {SUPERCOOLING APPARATUS}

It is installed in a refrigeration apparatus having a heat source unit and a use unit, and relates to a supercooling device for cooling the refrigerant sent from the heat source unit to the use unit through the liquid side communication pipe.

BACKGROUND ART Conventionally, subcooling devices are known which are installed in a refrigerating device for the purpose of increasing the cooling capacity and cool the refrigerant sent from the heat source unit to the use unit.

For example, the supercooling apparatus disclosed in Patent Document 1 is installed in an air conditioner including an outdoor unit and an indoor unit. Specifically, the subcooling device is provided in the middle of the liquid side communication pipe connecting the outdoor unit and the indoor unit, and includes a subcooling refrigerant circuit. The supercooling apparatus circulates the refrigerant in the subcooling refrigerant circuit to perform the freezing circulation, and cools the air conditioner refrigerant sent from the liquid side communication pipe in the evaporator of the subcooling refrigerant circuit. The supercooling device improves the cooling capability by cooling the liquid refrigerant sent from the outdoor unit of the air conditioner to the indoor unit and lowering the enthalpy of the liquid refrigerant sent to the indoor unit.

As described above, the subcooling device is for assisting a refrigerating device such as an air conditioner to increase its cooling capacity. Therefore, it is meaningless to operate only the supercooling device while the freezing device is stopped. It is also meaningless to operate the supercooling device in a state in which the refrigerating device operates as a heat pump like the heating operation of the air conditioner. In this way, in determining whether to operate the subcooling apparatus, it is necessary to know the operation state of the refrigerating apparatus in which the subcooling apparatus is installed.

Therefore, in the conventional subcooling apparatus disclosed in Patent Document 1, the control unit of the subcooling apparatus is connected with the control unit of the air conditioner to configure one control system. The control unit of the supercooling device receives a signal indicating the operating state of the air conditioner from the control unit of the air conditioner. In this supercooling device, the operation control is executed based on the signal input from the control unit of the air conditioner.

[Patent Document 1] Japanese Patent Application Laid-Open No. 10-185333

Disclosure of the Invention

Problems to be Solved by the Invention

As described above, the conventional subcooling device communicates with the refrigeration apparatus to which it is installed. Therefore, when the supercooling device is installed in the refrigerating device, wiring work for transmitting and receiving signals between the two devices is required, and there is a problem that the installation work of the supercooling device is complicated. In addition, a wiring error may occur when the supercooling device is installed, and there is a fear of causing a failure due to an operation error during such installation work.

SUMMARY OF THE INVENTION The present invention has been made in view of this point, and an object thereof is to enable operation control of a supercooling device without exchanging a signal with a refrigeration device to be installed, thereby simplifying the installation work of the supercooling device. In addition, it is to prevent failure due to human error during installation work.

Means to solve the problem

The first invention is provided in the refrigerating device 10 for circulating a heat source-side refrigerant between the heat source unit 11 and the use units 12, 13, 14 connected by a communication pipe to perform a freezing circulation, The subcooling device for cooling the heat source side refrigerant of the refrigerating device 10 sent from 11) to the use units 12, 13, 14 is intended. And a refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10, a cooling fluid circuit 220 through which the cooling fluid flows, and a heat source side in the refrigerant passage 205. The subcooling heat exchanger 210 for cooling the refrigerant by heat exchange with the cooling fluid, and the flow state of the cooling fluid in the cooling fluid circuit 220 in the heat source-side refrigerant in the refrigerant passage 205. It is provided with a control means 240 for controlling according to the state.

In the refrigerating device 10 in which the subcooling device 200 is installed in the first invention, a refrigerant flows between the heat source unit 11 and the use units 12, 13, and 14 through a communication pipe. The refrigerant passage 205 of the subcooling apparatus 200 is connected to the liquid side communication pipes 21 and 22 of the refrigerating apparatus 10, and the refrigerant inside the heat source side of the refrigerating apparatus 10 flows. In the cooling fluid circuit 220 of the subcooling device 200, the cooling fluid flows. In the subcooling heat exchanger (210), the heat source side refrigerant flowing in the refrigerant passage (205) is cooled by heat exchange with the cooling fluid.

The supercooling device 200 of the present invention is for assisting the operation of the refrigerating device 10. Therefore, the operation of the subcooling device 200 is necessary only during the operation of the refrigerating device 10, it is meaningless to operate only the subcooling device 200 during the stop of the refrigerating device 10. In addition, the subcooling device 200 of the present invention is for increasing the cooling capacity in the use units 12, 13, and 14. For this reason, for example, in the state where the refrigeration apparatus 10 functions as a heat pump, even if the subcooling apparatus 200 is operated, a substantial benefit cannot be expected. As described above, the subcooling device 200 may or may not be operated depending on the operation state of the refrigerating device 10.

In contrast, in the subcooling apparatus 200 of the present invention, the control means 240 controls the cooling fluid circulation state of the cooling fluid circuit 220. At this time, the control means 240 controls the flow state of the cooling fluid in accordance with the heat source-side refrigerant flow state in the refrigerant passage 205. In the coolant passage 205, the heat source side refrigerant flowing between the heat source unit 11 and the use units 12, 13, 14 through the liquid side communication pipes 21, 22 flows. Therefore, it is possible to determine the operation state of the refrigerating device 10 based on the refrigerant circulation state in the refrigerant passage 205. Thus, the control means 240 of the supercooling device 200 according to the heat source-side refrigerant flow state in the refrigerant passage 205 without receiving a signal relating to the operation state of the refrigerating device 10 from the freezing device 10, The cooling fluid circulation state in the cooling fluid circuit 220 is controlled.

According to a second aspect of the present invention, the cooling fluid circuit includes a subcooling refrigerant circuit 220, and the subcooling refrigerant circuit 220 includes a subcooling compressor 221 and a cooling fluid. As a result, the supercooling refrigerant is circulated to perform the freezing cycle.

In the second invention, in the subcooling refrigerant circuit 220 of the subcooling device 200, a refrigeration cycle is performed by circulating the subcooling refrigerant. In the subcooling heat exchanger 210, the heat source side refrigerant flowing in the refrigerant passage 205 is exchanged with the subcooling refrigerant. In this subcooling heat exchanger (210), the supercooling refrigerant absorbs and evaporates from the heat source side refrigerant, and the heat source side refrigerant is cooled.

In the second invention, in the second invention, the control means 240 controls the operation of the subcooling compressor 221 to control the subcooling refrigerant circulation state of the subcooling refrigerant circuit 220. will be.

In the third invention, when the control means 240 adjusts the operating capacity of the subcooling compressor 221, the amount of circulation of the subcooling refrigerant in the subcooling refrigerant circuit 220 changes. Therefore, when the operation of the subcooling compressor 221 is controlled, the subcooling refrigerant circulation state in the subcooling refrigerant circuit 220 is controlled accordingly.

In the fourth invention, in the third invention, the control means 240 includes a heat source-side refrigerant flow direction in the refrigerant passage 205 during operation of the subcooling compressor 221 and a heat source in the refrigerant passage 205. The supercooling compressor detects the presence or absence of the side refrigerant flow as the flow state of the heat source side refrigerant, and the inside of the refrigerant passage 205 flows from the heat source unit 11 toward the use unit 12, 13, 14 in the heat source side refrigerant. 221 continues to operate, the state in which the heat source side refrigerant flows from the use unit (12, 13, 14) toward the heat source unit 11 in the refrigerant passage 205 and the heat source in the refrigerant passage (205) It is configured to stop the subcooling compressor 221 in the state where the side refrigerant does not flow.

In the fourth invention, the control means 240 detects the refrigerant flow state during the operation of the subcooling compressor 221. Specifically, the control means 240 detects the coolant flow direction in the coolant passage 205 and the presence or absence of coolant flow in the coolant passage 205 as the coolant flow state.

The control means 240 of the present invention performs operation control of the subcooling compressor 221 based on the detected flow state of the refrigerant. In the state where the refrigerant flows from the heat source unit 11 toward the use unit 12, 13, 14 in the refrigerant passage 205, the refrigerating device 10 cools the object in the use unit 12, 13, 14. It can be determined that the operation. In this state, the control means 240 continues the operation of the subcooling compressor 221 so that the subcooling device 200 cools the refrigerant from the heat source unit 11 toward the use units 12, 13, 14. . On the other hand, in the state where the refrigerant flows in the refrigerant passage 205 toward the heat source unit 11 in the use unit 12, 13, 14, or in the state where the refrigerant does not flow in the refrigerant passage 205, the refrigerating device ( It may be determined that 10) does not operate to cool the object in the use units 12, 13, and 14. Therefore, in this state, the control means 240 stops the operation of the subcooling compressor 221, thereby avoiding unnecessary operation of the subcooling device 200.

In the fourth invention, in the fourth invention, the control means 240 is configured to start the subcooling compressor 221 when a predetermined time elapses when the subcooling compressor 221 is stopped.

In the fifth invention, the control means 240 calculates the elapsed time from the time when the subcooling compressor 221 is stopped. The control means 240 starts the subcooling compressor 221 when a predetermined time elapses from the stop of the subcooling compressor 221. The control means 240 detects the state of the refrigerant flow in the refrigerant passage 205 after the subcooling compressor 221 is started, and accordingly, the operation of the subcooling compressor 221 is continued or not. It is determined whether to stop 221.

In a sixth invention, in the third, fourth, or fifth invention, the heat source side refrigerant temperature of the portion of the refrigerant passage 205 on the side of the use unit (12, 13, 14) is more than the subcooling heat exchanger (210). And a coolant temperature detecting means 236 for detecting, while the control means 240 is a heat source based on a detected value change of the coolant temperature detecting means 236 from the time when the subcooling compressor 221 is started. It is configured to determine the distribution state of the side refrigerant.

In the sixth invention, the coolant temperature detecting unit 236 is configured in the subcooling apparatus 200. The coolant temperature detecting unit 236 detects the coolant temperature in the coolant passage 205 at the portion of the use unit 12, 13, 14 rather than the supercooling heat exchanger 210.

The control means 240 of the present invention judges the coolant flow state of the coolant passage 205 on the basis of the change of the detected value of the coolant temperature detecting means 236 from the time when the subcooling compressor 221 is started. . For example, in a state where the detection value of the refrigerant temperature detecting means 236 decreases as time elapses from the start of the subcooling compressor 221, the temperature of the refrigerant cooled in the subcooling heat exchanger 210 is changed to the refrigerant. It may be determined that the temperature is detected by the temperature detecting means 236, and as a result, the refrigerant passage 205 may determine that the refrigerant flows from the heat source unit 11 toward the use units 12, 13, and 14. . In the state where the detection value of the refrigerant temperature detecting means 236 does not change even after a time elapses from the start of the subcooling compressor 221, the refrigerant temperature before flowing into the subcooling heat exchanger 210 is determined by the refrigerant temperature detecting means ( 236 may be detected, or it may be determined that the refrigerant does not flow in the refrigerant passage 205.

In the third, fourth or fifth invention, the heat source side refrigerant temperature of the portion of the refrigerant passage 205 on the side of the use unit (12, 13, 14) is more than the subcooling heat exchanger (210). And a refrigerant temperature detecting means 236 for detecting and an evaporating temperature detecting means 234 for detecting an evaporating temperature of the subcooling refrigerant in the subcooling heat exchanger 210, while the control means 240 includes: The distribution value of the heat source-side refrigerant is determined based on the detection value of the refrigerant temperature detection means 236 and the detection value of the evaporation temperature detection means 234.

In the seventh invention, the supercooling device 200 is configured with a refrigerant temperature detecting unit 236 and an evaporation temperature detecting unit 234. The coolant temperature detecting unit 236 detects the coolant temperature in the coolant passage 205 at the portion of the use unit 12, 13, 14 rather than the supercooling heat exchanger 210. The evaporation temperature detecting means 234 detects the evaporation temperature of the subcooling refrigerant in the subcooling heat exchanger 210.

The control means 240 of the present invention judges the refrigerant circulation state in the refrigerant passage 205 based on the detection value of the refrigerant temperature detection means 236 and the detection value of the evaporation temperature detection means 234. . For example, when the detected value of the refrigerant temperature detecting means 236 is slightly higher than the detected value of the evaporating temperature detecting means 234, the temperature of the refrigerant cooled in the supercooling heat exchanger 210 is determined by the refrigerant temperature detecting means ( 236, it is determined that the refrigerant flows from the heat source unit 11 toward the use unit 12, 13, 14 in the refrigerant passage 205. If the detected value of the refrigerant temperature detecting means 236 is significantly higher than the detected value of the evaporating temperature detecting means 234, the refrigerant temperature before flowing into the subcooling heat exchanger 210 is the refrigerant temperature detecting means 236. It may be determined that the refrigerant is not distributed through the refrigerant passage 205 or the refrigerant is detected.

In the third, fourth or fifth invention, the heat source side refrigerant temperature of the portion of the refrigerant passage 205 on the side of the use unit (12, 13, 14) is detected more than the subcooling heat exchanger (210). Second refrigerant temperature detection means (237) and second refrigerant temperature detection means for detecting a heat source side refrigerant temperature of the portion of the heat source unit (11) than the subcooling heat exchanger (210) of the refrigerant passage (205); And the control means 240 distributes the heat source-side refrigerant based on the detection value of the first refrigerant temperature detection means 237 and the detection value of the second refrigerant temperature detection means 238. It is configured to determine the state.

In the eighth invention, the subcooling apparatus 200 includes a first refrigerant temperature detecting means 237 and a second refrigerant temperature detecting means 238. The first refrigerant temperature detecting unit 237 detects the refrigerant temperature in the portion of the refrigerant passage 205 in the use unit 12, 13, 14, rather than the subcooling heat exchanger 210. The second refrigerant temperature detecting means 238 detects the refrigerant temperature in the heat source unit 11 side of the refrigerant passage 205 rather than the subcooling heat exchanger 210.

The control means 240 of this invention is based on the detection value of the said 1st refrigerant | coolant temperature detection means 237, and the detected value of the said 2nd refrigerant | coolant temperature detection means 238, The refrigerant | coolant circulation state of the refrigerant | coolant passage 205 is carried out. Judge. For example, in a state where the detected value of the first refrigerant temperature detecting means 237 is lower than the detected value of the second refrigerant temperature detecting means 238, the heat source unit 11 to the use unit 12, 13, 14 is used. It may be determined that the refrigerant to be cooled in the subcooling heat exchanger (210). On the contrary, in the state where the detected value of the first refrigerant temperature detecting means 237 is sufficiently higher than the detected value of the second refrigerant temperature detecting means 238, the use unit 12, 13, 14 is directed toward the heat source unit 11. It may be determined that the refrigerant is cooled in the subcooling heat exchanger 210. In the state where the detected value of the first refrigerant temperature detecting means 237 and the detected value of the second refrigerant temperature detecting means 238 are almost the same, it can be determined that the refrigerant has not flowed in the refrigerant passage 205.

In the ninth invention, in the first, second or third invention, the refrigerant passage 205 is provided with a flow meter 251 for detecting the amount of the heat source-side refrigerant flow, while the control means 240 is By using the detected value of the flowmeter 251 as a flow state display value indicating the flow state of the heat source side refrigerant, the flow of the cooling fluid flows in the state where the cooling fluid flows in the cooling fluid circuit 220. And to determine whether to continue or stop based on the distribution status indication value.

In the ninth invention, the detection value of the flow meter 251 is input to the control means 240. The heat source side refrigerant flow state of the refrigerant passage 205 can be determined by the detection value of the flow meter 251. Thus, the control means 240 uses the detected value of the flow meter 251 as the flow state display value, and controls the cooling fluid flow state in the cooling fluid circuit 220 based on the flow state display value. .

In the tenth invention, in the first, second or third invention, the heat source side refrigerant temperature of the portion of the refrigerant passage 205 on the side of the use unit (12, 13, 14) is more than the subcooling heat exchanger (210). Second refrigerant temperature detection means for detecting the first refrigerant temperature detection means 237 for detecting and the heat source side refrigerant temperature of the heat source unit 11 side than the subcooling heat exchanger 210 in the refrigerant passage 205. And the control means 240 distributes the difference between the detected value of the first refrigerant temperature detection means 237 and the detected value of the second refrigerant temperature detection means 238 to distribute the heat source-side refrigerant. Using the flow state display value indicating the state, in the state where the cooling fluid flows in the cooling fluid circuit 220, the flow of the cooling fluid is continued or stopped based on the flow state display value. It is configured to determine.

In the tenth invention, the detection values of the first refrigerant temperature detection means 237 and the second refrigerant temperature detection means 238 are input to the control means 240. When the detection value of the first refrigerant temperature detection means 237 and the detection value of the second refrigerant temperature detection means 238 are compared, it is possible to determine the heat source-side refrigerant distribution state in the refrigerant passage 205. For example, if the detected value of the first refrigerant temperature detecting means 237 is lower than the detected value of the second refrigerant temperature detecting means 238, the inside of the refrigerant passage 205 may be used in the heat source unit 11. 13, 14, it can be determined that the heat source side refrigerant flows. Otherwise, it may be determined that the heat source side refrigerant flows from the use unit 12, 13, 14 toward the heat source unit 11, or that the heat source side refrigerant does not flow in the refrigerant passage 205. Thus, the control means 240 uses the difference between the detection value of the first refrigerant temperature detection means 237 and the detection value of the second refrigerant temperature detection means 238 as the distribution state display value, and based on this distribution state display value. By controlling the flow state of the cooling fluid in the cooling fluid circuit (220).

In the eleventh invention, in the first, second or third invention, the heat source side refrigerant temperature of the portion of the refrigerant passage 205 on the side of the use unit (12, 13, 14) is more than the subcooling heat exchanger (210). While the coolant temperature detecting means 236 is detected, the control means 240 uses the change in the detected value of the coolant temperature detecting means 236 as a flow state display value indicating a flow state of the heat source side refrigerant. In the state where the cooling fluid flows in the cooling fluid circuit 220, the cooling fluid circuit 220 is configured to determine whether to continue or stop the distribution of the cooling fluid based on the flow state display value.

In the eleventh invention, the detection value of the refrigerant temperature detecting means 236 is input to the control means 240. By monitoring the change in the detection value of the coolant temperature detecting means 236, it is possible to determine the heat source-side coolant distribution state in the coolant passage 205. For example, when the detection value of the refrigerant temperature detecting means 236 decreases while the cooling fluid flows, the inside of the refrigerant passage 205 is moved from the heat source unit 11 toward the use unit 12, 13, 14. It can be judged that the heat source side refrigerant flows. Otherwise, it may be determined that the heat source side refrigerant flows from the use unit 12, 13, 14 toward the heat source unit 11, or that the heat source side refrigerant does not flow in the refrigerant passage 205. Therefore, the control means 240 uses the detected value of the refrigerant temperature detecting means 236 as the flow state display value, and based on the flow state display value, the control means 240 determines the fluid flow state for cooling in the cooling fluid circuit 220. To control.

In the twelfth invention, in the first, second or third invention, the inlet fluid temperature detecting means for detecting the cooling fluid temperature at the inlet of the supercooling heat exchanger 210 is provided in the cooling fluid circuit 220. 252 and an outlet side fluid temperature detection means 253 for detecting the cooling fluid temperature at the outlet of the subcooling heat exchanger 210, the control means 240 is the inlet fluid temperature. Cooling is performed in the cooling fluid circuit 220 by using the difference between the detection value of the detection means 252 and the detection value of the outlet-side fluid temperature detection means 253 as a flow state display value indicating the flow state of the heat source side refrigerant. It is configured to determine whether to continue or stop the flow of this cooling fluid in the state where the fluid flows, based on the flow state display value.

In the twelfth invention, the inlet fluid temperature detection means 252 and the outlet fluid temperature detection means 253 detected values are input to the control means 240. Comparing the detected value of the inlet fluid temperature detecting means 252 and the detected value of the inlet fluid temperature detecting means 252, it is possible to determine the heat source-side refrigerant distribution state in the coolant passage 205. For example, if the detected value of the inlet fluid temperature detecting means 252 is higher than the detected value of the inlet fluid temperature detecting means 252, the inside of the refrigerant passage 205 may be used in the heat source unit 11. 13, 14, it can be determined that the heat source side refrigerant flows. Otherwise, it may be determined that the heat source side refrigerant flows from the use unit 12, 13, 14 toward the heat source unit 11, or that the heat source side refrigerant does not flow in the refrigerant passage 205. Thus, the control means 240 uses the difference between the detected value of the inlet fluid temperature detecting means 252 and the detected value of the outlet fluid temperature detecting means 253 as the distribution status display value, and based on this distribution status display value. The cooling fluid circulation state in the cooling fluid circuit 220 is controlled.

In the thirteenth invention, in the second or third invention, the subcooling refrigerant circuit 220 includes evaporation pressure detecting means 234 for detecting an evaporation pressure of the subcooling refrigerant in the subcooling heat exchanger 210. Meanwhile, the control means 240 uses the detected value of the evaporation pressure detecting means 234 as a flow state display value indicating the flow state of the heat source-side refrigerant, and the subcooling refrigerant circuit 220 for subcooling. In the state where the coolant circulates, the coolant is configured to determine whether to continue or stop the circulation of the supercooling coolant based on the distribution state display value.

In the thirteenth invention, the detection value of the evaporation pressure detecting means 234 is input to the control means 240. By monitoring the change in the detection value of the evaporation pressure detecting means 234, it is possible to determine the heat source-side refrigerant distribution state in the refrigerant passage 205. For example, when the detection value of the evaporation pressure detecting means 236 is above a certain level in the state where the supercooling refrigerant is circulated, it can be determined that the heat source side refrigerant flows through the refrigerant passage 205. Otherwise, it may be determined that the heat source side refrigerant did not flow in the refrigerant passage 205. Thus, the control means 240 uses the detected value of the evaporation pressure detecting means 236 as the flow state display value, and based on the flow state display value, the control means 240 determines the flow state of the supercooled refrigerant flow in the subcooling refrigerant circuit 220. To control.

In the second or third aspect of the invention, in the second or third invention, a refrigerant for detecting a heat source side refrigerant temperature of the portion of the refrigerant passage 205 on the side of the use unit (12, 13, 14) rather than the subcooling heat exchanger (210). And a temperature detecting means 236 and evaporating temperature detecting means 234 for detecting the evaporating temperature of the subcooled refrigerant in the subcooling heat exchanger 210, while the control means 240 detects the refrigerant temperature. By using the difference between the detected value of the means 236 and the detected value of the evaporation temperature detection means 234 as a flow state display value representing the flow state of the heat source-side refrigerant, the supercooled refrigerant in the subcooled refrigerant circuit 220 In the circulating state, it is configured to determine whether to continue or stop the circulation of the supercooling refrigerant based on the distribution state display value.

In the fourteenth invention, the detection values of the refrigerant temperature detection means 236 and the evaporation temperature detection means 234 are input to the control means 240. Comparing the detection value of the refrigerant temperature detection means 236 with the detection value of the evaporation temperature detection means 234, it is possible to determine the heat source-side refrigerant distribution state in the refrigerant passage 205. For example, when the difference between the detection value of the refrigerant temperature detection means 236 and the detection value of the evaporation temperature detection means 234 is within a predetermined value (for example, about 10 ° C.), the heat source unit 11 is introduced into the refrigerant passage 205. ), It can be determined that the heat source-side refrigerant flows toward the use unit (12, 13, 14). Otherwise, it may be determined that the heat source side refrigerant flows from the use unit 12, 13, 14 toward the heat source unit 11, or that the heat source side refrigerant does not flow in the refrigerant passage 205. Thus, the control means 240 uses the difference between the detected value of the refrigerant temperature detecting means 236 and the detected value of the evaporation temperature detecting means 234 as the circulation state display value, and based on this circulation state display value, the refrigerant circuit for subcooling The supercoolant refrigerant distribution state of 220 is controlled.

In the fifteenth invention, in the first, second or third invention, the heat source side refrigerant temperature of the portion of the refrigerant passage 205 on the side of the use unit (12, 13, 14) is more than the subcooling heat exchanger (210). While the coolant temperature detecting means 236 is detected, the control means 240 uses the detected value of the coolant temperature detecting means 236 as a flow state display value indicating a flow state of the heat source side refrigerant. In the cooling fluid circuit 220, when the flow of the cooling fluid is stopped, the cooling fluid circuit 220 is configured to determine whether to start the flow of the cooling fluid or to continue the stop state based on the displayed value of the flow state.

In the fifteenth invention, the detection value of the refrigerant temperature detecting means 236 is input to the control means 240. By monitoring the detection value of the refrigerant temperature detecting means 236, it is possible to determine the heat source-side refrigerant distribution state in the refrigerant passage 205. For example, if the detected value of the coolant temperature detection means 236 is a certain value or more in a state where the flow of the cooling fluid is stopped, the refrigerant unit 205 may be used in the heat source unit 11 in the heat source unit 11. 13, 14, it can be determined that the heat source side refrigerant flows. Otherwise, it may be determined that the heat source side refrigerant flows from the use unit 12, 13, 14 toward the heat source unit 11, or that the heat source side refrigerant does not flow in the refrigerant passage 205. Thus, the control means 240 controls the cooling fluid flow state of the cooling fluid circuit 220 based on the flow state display value by using the change in the detected value of the refrigerant temperature detecting means 236 as the flow state display value. do.

In the sixteenth invention, in the first, second, or third invention, the heat source-side refrigerant temperature of the portion of the refrigerant passage 205 on the side of the use unit (12, 13, 14) is more than the subcooling heat exchanger (210). And a coolant temperature detection means 236 for detecting, while the control means 240 uses the change in the detected value of the coolant temperature detection means 236 as a flow state display value indicating a flow state of the heat source side refrigerant. The flow of the cooling fluid in the cooling fluid circuit 220 is stopped, and it is configured to determine whether to start the flow of the cooling fluid or to continue the stop state based on the flow state display value.

In the sixteenth invention, the detection value of the refrigerant temperature detecting means 236 is input to the control means 240. By monitoring the change in the detection value of the coolant temperature detecting means 236, it is possible to determine the heat source-side coolant distribution state in the coolant passage 205. For example, when the detection value of the coolant temperature detecting means 236 rises while the flow of the cooling fluid stops, the inside of the coolant passage 205 is used by the heat source unit 11 in the use unit 12, 13,. It may be determined that the heat source-side refrigerant flows toward 14). Otherwise, it may be determined that the heat source side refrigerant flows in the refrigerant passage 205 toward the heat source unit 11 from the use units 12, 13, and 14, or that the heat source side refrigerant does not flow. Thus, the control means 240 uses the change of the detected value of the refrigerant temperature detecting means 236 as the flow state display value, and based on the flow state display value, the control means 240 determines the fluid flow state for cooling in the cooling fluid circuit 220 based on the flow state display value. To control.

In the seventeenth invention, in the second or third invention, the outdoor unit (231) for detecting the temperature of the outdoor air and the refrigerant passage (205), the use unit (12) rather than the supercooling heat exchanger (210) And the refrigerant temperature detecting means 236 for detecting the refrigerant temperature of the heat source side of the portions 13, 14 and 14, while the control means 240 detects the detected value of the refrigerant temperature detecting means 236 and the outdoor temperature. By using the difference in the detected value of the means 231 as a distribution state display value indicating the distribution state of the heat source side refrigerant, the subcooling refrigerant circuit 220 stops the distribution of the subcooling refrigerant. And to determine whether to start the distribution or to continue the stopped state based on the distribution status indication value.

In the seventeenth invention, the detection values of the outdoor temperature detection means 231 and the refrigerant temperature detection means 236 are input to the control means 240. Comparing the detection value of the refrigerant temperature detection means 236 with the detection value of the outdoor temperature detection means 231, it is possible to determine the heat source-side refrigerant distribution state in the refrigerant passage 205. For example, if the difference between the detected value of the refrigerant temperature detecting means 236 and the detected value of the outdoor temperature detecting means 231 is greater than or equal to the predetermined value while the flow of the cooling fluid is stopped, the inside of the refrigerant passage 205 is opened. It can be judged that the heat source side refrigerant flows. Otherwise, it may be determined that the heat source side refrigerant does not flow in the refrigerant passage 205. Thus, the control means 240 uses the difference between the detected value of the refrigerant temperature detecting means 236 and the detected value of the outdoor temperature detecting means 231 as the distribution state display value, and based on this distribution state display value, the refrigerant for supercooling. The supercoolant refrigerant flow state in the circuit 220 is controlled.

The eighteenth invention is provided in the refrigerating device (10) for circulating a heat source side refrigerant between the heat source unit (11) connected to the communication pipe and the use units (12, 13, 14) to perform a freezing circulation, The subcooling device for cooling the heat source side refrigerant of the refrigerating device 10 sent from 11) to the use units 12, 13, 14 is intended. The heat source unit 11 of the refrigerating device 10 is configured to heat-exchange the heat source-side refrigerant with outdoor air, while the refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10. ), A cooling fluid circuit 220 through which a cooling fluid flows, a subcooling heat exchanger 210 for cooling the heat source side refrigerant in the refrigerant passage 205 by heat exchange with the cooling fluid, and outdoor air. Outdoor temperature detecting means 231 for detecting the temperature of the control means, and control means 240 for controlling the state of the cooling fluid flow in the cooling fluid circuit 220 in accordance with the detection value of the outdoor temperature detecting means 231 It is to be provided.

In the eighteenth invention, as in the first invention, the heat source-side refrigerant in the refrigerant passage 205 is cooled by the cooling fluid. The detection value of the outdoor temperature detection means 231 is input to the control means 240 of this invention. By monitoring the detection value of the outdoor temperature detecting means 231, the magnitude of the cooling load in the use units 12, 13, and 14 can be estimated to determine whether to cool the heat source side refrigerant in the refrigerant passage 205. can do. Thus, the control means 240 controls the cooling fluid flow state in the cooling fluid circuit 220 based on the detection value of the outdoor temperature detecting means 231.

In a nineteenth aspect of the present invention, in the eighteenth invention, the cooling fluid circuit includes a subcooling refrigerant circuit 220, and the subcooling refrigerant circuit 220 includes a subcooling compressor 221, and a cooling fluid. As a result, the supercooling refrigerant is circulated to perform the freezing cycle.

In the nineteenth aspect of the present invention, in the subcooling refrigerant circuit 220 of the subcooling apparatus 200, a refrigerating circulation is performed by circulating a subcooling refrigerant. In the subcooling heat exchanger 210, the heat source side refrigerant flowing in the refrigerant passage 205 is exchanged with the subcooling refrigerant. In this subcooling heat exchanger (210), the supercooling refrigerant absorbs and evaporates from the heat source side refrigerant, and the heat source side refrigerant is cooled.

In the eighteenth or nineteenth aspect of the present invention, in the state where the cooling fluid flows in the cooling fluid circuit 220, the control means 240 continues or stops the flow of the cooling fluid. It is configured to determine based on the detection value of the outdoor temperature detection means 231.

In the twenty-first aspect of the present invention, in the eighteenth or nineteenth aspect of the present invention, the control means 240 starts the circulation of the cooling fluid in a state in which the cooling fluid circulation is stopped in the cooling fluid circuit 220. It is configured to determine based on the detection value of the outdoor temperature detection means 231 whether to continue the stop state.

In the 20th and 21st inventions, the control means 240 monitors the detection value of the outdoor temperature detection means 231. If the detected value of the outdoor temperature detecting means 231 exceeds a predetermined reference value (for example, 25 ° C.), the cooling load in the use units 12, 13, and 14 is increased and the heat source side refrigerant in the refrigerant passage 205 is increased. You can assume that you are in a situation where you need to cool down. Otherwise, it can be inferred that the cooling load in the use units 12, 13, 14 is not so large that the need for cooling the heat source side refrigerant in the refrigerant passage 205 is low. Thus, the control means 240 of the present invention determines whether to distribute the cooling fluid in the cooling fluid circuit 220 based on the detected value of the outdoor temperature detection means 231.

22nd invention is the heat dissipation heat exchanger 222 which is connected to the subcooling refrigerant circuit 220 to heat-exchange the supercooled refrigerant with outdoor air according to the second or 19th invention, and the heat dissipation heat exchanger 222 And an outdoor fan 230 for supplying outdoor air, and the subcooling refrigerant circuit 220 naturally circulates the subcooling refrigerant by operating the outdoor fan 230 while the subcooling compressor 221 is stopped. It is configured to enable a natural circulation operation, the control means 240 to start the circulation of the subcooled refrigerant to start the outdoor fan 230 and to execute the natural circulation operation to the subcooling refrigerant circuit 220 And according to the heat source-side refrigerant flow state in the refrigerant passage 205 during the natural circulation operation, it is configured to determine whether to start or stop the subcooling compressor 221.

In the twenty-second aspect of the present invention, in the subcooling refrigerant circuit 220, the subcooling refrigerant circulates even while the subcooling compressor 221 is stopped by operating the outdoor fan 230. That is, in the subcooling refrigerant circuit 220, the heat source side refrigerant can be cooled by the subcooling heat exchanger 210 only by operating the outdoor fan 230. When the circulation of the subcooled coolant is started, the control means 240 of the present invention operates only the outdoor fan 230 first, and then naturally circulates the subcooled coolant in the subcooled coolant circuit 220, thereby naturally circulating. The coolant on the heat source side is cooled by the coolant. Then, the control means 240 determines whether the cooling of the heat source side refrigerant is sufficient in this state, and determines whether to start the subcooling compressor 221 according to this determination. That is, the control means 240, if the cooling of the heat source side refrigerant is sufficient, the subcooling compressor 221 is stopped, and if the cooling of the heat source side refrigerant is insufficient, the control unit 240 starts the subcooling compressor 221 to cool the supercooling refrigerant circuit ( The freezing cycle in 220 is initiated.

Effects of the Invention

In the subcooling apparatus 200 of the present invention, the control means 240 controls the operation of the subcooling compressor 221 according to the refrigerant flow state inside the refrigerant passage 205. That is, in this subcooling apparatus 200, it is possible to control the operation of the subcooling compressor 221 in accordance with the operation state of the refrigerating apparatus 10, even if no signal is received between the refrigerating apparatus 10 and the like. Thus, when the subcooling device 200 of the present invention is installed in the refrigerating device 10, only the refrigerant passage 205 of the subcooling device 200 is connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10. And, there is no need to lay a communication wiring for sending and receiving signals between the freezing device 10 and the subcooling device 200.

Therefore, according to the present invention, it is possible to reduce the number of work steps when the supercooling device 200 is installed in the refrigerating device 10, and furthermore, to prevent failures due to human work errors during the installation work such as wiring errors. Can be.

1 is a piping system diagram showing a configuration of a refrigeration system having a subcooling unit.

2 is a piping system diagram showing the operation during the cooling operation of the refrigeration system.

3 is a piping system diagram showing an operation during a first heating operation of a refrigeration system.

4 is a piping system diagram showing an operation during a first heating operation of a refrigeration system.

5 is a piping system diagram showing an operation during the second heating operation of the refrigeration system.

6 is a flowchart showing the control operation of the controller in the subcooling unit.

7 is a piping system diagram showing a configuration of a refrigeration system in a first modification of the embodiment.

8 is a piping system diagram showing a configuration of a refrigeration system in a second modification of the embodiment.

9 is a piping system diagram showing a configuration of a refrigeration system according to a fifth modification of the embodiment.

10 is a piping system diagram showing the configuration of a supercooling unit in a tenth modification example of the embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail based on drawing.

The refrigeration system of this embodiment is installed in a convenience store etc. and performs air conditioning in a store and cooling in a showcase. This refrigerating system is comprised from the subcooling unit 200 as a subcooling apparatus which concerns on this invention, and the refrigerating apparatus 10 in which this subcooling unit 200 was provided.

As shown in Fig. 1, the refrigeration system includes an outdoor unit 11, an air conditioning unit 12, a refrigerated showcase 13, a refrigerated showcase 14, a booster unit 15, and a supercooling unit ( 200) is installed. The outdoor unit 11, the air conditioning unit 12, the refrigeration showcase 13, the freezing showcase 14, and the booster unit 15 form the refrigerating device 10. In this refrigeration system, the outdoor unit 11 and the subcooling unit 200 are installed outdoors, and the remaining air conditioning units 12 and the like are installed in stores such as convenience stores.

The outdoor unit 11 has an outdoor circuit 40, the air conditioning unit 12 has an air conditioning circuit 100, the cold showcase 13 has a refrigeration circuit 110, and the freezing showcase 14 has a refrigeration circuit 130. The booster unit 15 includes a booster circuit 140, respectively. In addition, the coolant passage 205 is disposed in the subcooling unit 200. In the refrigerating system, the refrigerant circuit 20 is configured by connecting these circuits 40, 100, ... and the refrigerant passage 205 of the subcooling unit 200 by piping. The refrigerant circuit 20 is filled with a heat source side refrigerant.

The refrigerant circuit 20 includes a first liquid side communication pipe 21, a second liquid side communication pipe 22, a first gas side communication pipe 23, and a second gas side communication pipe 24. do.

In the first liquid side communication pipe 21, one end of the refrigerant passage 205 of the subcooling unit 200 is connected to the outdoor circuit 40. One end of the second liquid side contact pipe 22 is connected to the other end of the refrigerant passage 205. The other end of the second liquid side contact pipe 22 is branched into three and connected to the air conditioning circuit 100, the refrigerating circuit 110, and the refrigerating circuit 130. The liquid side closing valve 25 is provided in the branch pipe connected to the freezing circuit 130 among the second liquid side contact pipes 22.

One end of the first gas side communication pipe 23 is branched into two and connected to the refrigerating circuit 110 and the booster circuit 140. The gas side closing valve 26 is provided in the branch pipe connected to the booster circuit 140 among the first gas side communication pipes 23. The other end of the first gas side communication pipe 23 is connected to the outdoor circuit 40. The second gas side communication pipe 24 connects the air conditioning circuit 100 with the outdoor circuit 40.

<Outdoor unit>

The outdoor unit 11 constitutes a heat source unit of the refrigerating device 10. This outdoor unit 11 includes an outdoor circuit 40.

The outdoor circuit 40 includes a variable capacity compressor 41, a first fixed capacity compressor 42, a second fixed capacity compressor 43, an outdoor heat exchanger 44, a receiver 45, An outdoor expansion valve 46 is configured. In addition, the outdoor circuit 40 includes three suction pipes 61, 62, 63, two discharge pipes 64, 65, four liquid pipes 81, 82, 83, 84, and one high-pressure gas pipe 66. ) Is configured. In addition, three cross switching valves 51, 52, 53, one liquid side closing valve 54, and two gas side closing valves 55, 56 are provided in the outdoor circuit 40.

In the outdoor circuit 40, the first liquid side communication pipe 21 is connected to the liquid side closing valve 54, and the first gas side communication pipe 23 is connected to the second gas side in the first gas side closing valve 55. A second gas side communication pipe 24 is connected to the closing valve 56, respectively.

The variable displacement compressor 41, the first fixed displacement compressor 42, and the second fixed displacement compressor 43 are all hermetic and high pressure dome scroll compressors. The variable capacity compressor 41 is supplied with power through an inverter. The variable displacement compressor 41 is configured such that its capacity can be changed by changing the output frequency of the inverter to change the rotational speed of the compressor motor. On the other hand, in the first and second fixed displacement compressors 42 and 43, the compressor motor is always operated at a constant rotational speed, and its capacity cannot be changed.

One end of the first suction pipe 61 is connected to the first gas side closing valve 55. The first suction pipe 61 is branched from the other end to the first branch pipe 61a and the second branch pipe 61b, and the first branch pipe 61a is connected to the suction side of the variable displacement compressor 41. The two branch pipes 61b are connected to the third four-way switching valve 53, respectively. In the second branch pipe 61b of the first suction pipe 61, a check valve CV-1 that allows only a flow of refrigerant from the first gas side closing valve 55 to the third four-way valve 53 is provided. Is installed.

One end of the second suction pipe 62 is connected to the third four-way valve 53 and the other end of the second suction pipe 62 is connected to the suction side of the first fixed displacement compressor 42.

One end of the third suction pipe 63 is connected to the second four-way switching valve 52. The third suction pipe 63 is branched from the other end to the first branch pipe 63a and the second branch pipe 63b, and the first branch pipe 63a is connected to the suction side of the second fixed displacement compressor 43. And the second branch pipe 63b are connected to the third four-way switching valve 53, respectively. A check valve CV-2 is provided in the second branch pipe 63b of the third suction pipe 63 to allow only the flow of the refrigerant from the second four way switching valve 52 to the third four way switching valve 53. do.

The first discharge pipe 64 is branched from one end to the first branch pipe 64a and the second branch pipe 64b, and the first branch pipe 64a is connected to the discharge side of the variable displacement compressor 41 for the second minute. The engine 64b is connected to the discharge side of the first fixed displacement compressor 42, respectively. The other end of the first discharge pipe 64 is connected to the first four way switching valve 51. In the second branch pipe 64b of the first discharge pipe 64, a check valve CV-3 that allows only a flow of refrigerant from the first fixed displacement compressor 42 to the first cross-over valve 51 is provided. Is installed.

One end of the second discharge pipe 65 is connected to the suction side of the second fixed displacement compressor 43, and the other end thereof is directly in front of the first cross switching valve 51 of the first discharge pipe 64. The second discharge pipe 65 is provided with a check valve CV-4 that allows only the flow of the refrigerant from the second fixed displacement compressor 43 to the first four way switching valve 51.

The outdoor heat exchanger 44 is a cross fin fin tube heat exchanger. In the outdoor heat exchanger (44), heat exchange is performed between the refrigerant and outdoor air. One end of the outdoor heat exchanger 44 is connected to the first four way switching valve 51 via a closing valve 57. On the other hand, the other end of the outdoor heat exchanger 44 is connected to the top of the receiver 45 via the first liquid pipe 81. The first liquid pipe 81 is provided with a check valve CV-5 that allows only the flow of the refrigerant from the outdoor heat exchanger 44 to the receiver 45.

One end of the second liquid pipe 82 is connected to the bottom of the receiver 45 via a closing valve 58. The other end of the second liquid pipe 82 is connected to the liquid side closing valve 54. The second liquid pipe 82 is provided with a check valve CV-6 which allows only the flow of the refrigerant from the receiver 45 to the liquid side closing valve 54.

One end of the third liquid pipe 83 is connected between the check valve CV-6 of the second liquid pipe 82 and the liquid side closing valve 54. The other end of the third liquid pipe 83 is connected to the top of the receiver 45 via the first liquid pipe 81. In addition, the third liquid pipe 83 is provided with a check valve CV-7 that allows only the flow of the refrigerant from one end to the other.

One end of the fourth liquid pipe 84 is connected between the closing valve 58 of the second liquid pipe 82 and the check valve CV-6. The other end of the fourth liquid pipe 84 is connected between the outdoor heat exchanger 44 of the first liquid pipe 81 and the check valve CV-5. Further, the check valve CV-8 and the outdoor expansion valve 46 are provided in the fourth liquid pipe 84 in order from one end to the other end. This check valve CV-8 allows only the circulation of the refrigerant from one end of the fourth liquid pipe 84 to the other end. The outdoor expansion valve 46 is constituted by an electromagnetic expansion valve.

One end of the high pressure gas pipe 66 is connected directly to the first four-way switching valve 51 of the first discharge pipe 64. The high pressure gas pipe 66 is branched from the other end to the first branch pipe 66a and the second branch pipe 66b, and the first branch pipe 66a is the check valve CV-5 of the first liquid pipe 81. On the downstream side, the second branch pipe 66b is connected to the third four-way switching valve 53, respectively. An electromagnetic valve SV-7 and a check valve CV-9 are provided in the first branch pipe 66a of the high pressure gas pipe 66. This check valve CV-9 is disposed downstream of the solenoid valve SV-7 and permits only the flow of refrigerant from the solenoid valve SV-7 to the first liquid pipe 81.

The first four-way valve 51 has a first port at the end of the first discharge pipe 64, a second port at the second four-way valve 52, and a third port at the outdoor heat exchanger 44. And a fourth port are connected to the second gas side closing valve 56, respectively. The first four-way valve 51 has a first state in which the first port and the third port communicate with each other, and the second port and the fourth port communicate with each other, and a first port. And the fourth port communicate with each other, and the second port and the third port communicate with each other, and are configured to be switchable to a second state (state indicated by a dotted line in FIG. 1).

The second four-way switching valve 52 has a first port at a downstream side of the check valve CV-4 of the second discharge pipe 65, a second port at a start end of the second suction pipe 62, and a fourth port. Are respectively connected to the second ports of the first four way switching valve 51. In addition, the second four-way switching valve 52 is sealed with a third port. The second four-way switching valve 52 has a first state in which the first port and the third port communicate with each other, and the second port and the fourth port communicate with each other, and a first port. And the fourth port communicate with each other, and the second port and the third port communicate with each other, and are configured to be switchable to a second state (state indicated by a dotted line in FIG. 1).

The third four-way valve 53 has a first port at the end of the second branch pipe 66b of the high-pressure gas pipe 66, a second port at the start end of the second suction pipe 62, and a third port The fourth port is connected to the last end of the second branch pipe 63b of the third suction pipe 63 at the end of the second branch pipe 61b of the first suction pipe 61. The third four-way valve 53 has a first state in which the first port and the third port communicate with each other, and the second port and the fourth port communicate with each other, and a first port. And the fourth port communicate with each other, and the second port and the third port communicate with each other, and are configured to be switchable to a second state (state indicated by a dotted line in FIG. 1).

The outdoor circuit 40 further includes an injection tube 85, a communication tube 87, an oil separator 75, and an oil recovery tube 76. In addition, four fungal oil pipes 71, 72, 73, and 74 are also configured in the outdoor circuit 40.

The injection pipe 85 is for performing so-called liquid injection. One end of the injection pipe 85 is connected between the check valve CV-8 of the fourth liquid pipe 84 and the outdoor expansion valve 46, and the other end thereof is connected to the first suction pipe 61, respectively. The injection pipe 85 is provided with a closing valve 59 and a flow regulating valve 86 in order from one end to the other end. The flow control valve 86 is composed of an electromagnetic expansion valve.

The communication pipe 87 has one end between the closing valve 59 of the injection pipe 85 and the flow regulating valve 86, and the other end of the solenoid valve in the first branch pipe 66a of the high-pressure gas pipe 66. (SV-7) are respectively connected upstream. The communicating tube 87 is provided with a check valve CV-10 that allows only the flow of the refrigerant from one end to the other.

The oil separator 75 is disposed upstream from the connection position of the second discharge pipe 65 and the high pressure gas pipe 66 among the first discharge pipes 64. This oil separator 75 is for separating the refrigeration oil from the discharge gas of the compressors 41 and 42.

One end of the oil return pipe 76 is connected to an oil separator 75. The oil return pipe 76 is branched from the other end to the first branch pipe 76a and the second branch pipe 76b, and the first branch pipe 76a is a flow control valve 86 of the injection pipe 85. On the downstream side, the second branch pipe 76b is connected to the second suction pipe 62, respectively. In addition, the solenoid valves SV-5 and SV-6 are provided in the 1st branch pipe 76a and the 2nd branch pipe 76b of the oil return pipe 76 one by one. When the solenoid valve SV-5 of the first branch pipe 76a is opened, the refrigeration oil separated from the oil separator 75 is returned to the first suction pipe 61 through the injection pipe 85. On the other hand, when the solenoid valve SV-6 of the 2nd branch pipe 76b is opened, the refrigeration oil isolate | separated from the oil separator 75 is returned to the 2nd suction pipe 62. As shown in FIG.

One end of the first fungal oil tube 71 is connected to the variable displacement compressor 41, and the other end thereof is connected to the second suction tube 62. The first fungal oil pipe 71 is provided with a solenoid valve SV-1. One end of the second fungal oil pipe 72 is connected to the first fixed displacement compressor 42, and the other end thereof is connected to the first branch pipe 63a of the third suction pipe 63. The second fungal oil pipe 72 is provided with a solenoid valve SV-2. One end of the third fungal oil tube 73 is connected to the second fixed displacement compressor 43, and the other end thereof is connected to the first branch pipe 61a of the first suction pipe 61. The third fungal oil pipe 73 is provided with a solenoid valve SV-3. One end of the fourth fungal oil pipe 72 is connected to the upstream side of the solenoid valve SV-2 of the second fungal oil pipe 72, and the other end thereof is connected to the first branch pipe 61 a of the first suction pipe 61. Connected. The fourth fungal oil pipe 74 is provided with a solenoid valve SV-4. By appropriately opening and closing the solenoid valves SV-1 to SV-4 of each of the fungal oil pipes 71 to 74, the amount of refrigeration oil storage of each of the compressors 41, 42 and 43 is averaged.

The outdoor circuit 40 is also provided with various sensors and pressure switches. Specifically, the first suction pipe 61 is provided with a first suction temperature sensor 91 and a first suction pressure sensor 92. The second suction pressure sensor 93 is installed in the second suction pipe 62. A third suction temperature sensor 94 and a third suction pressure sensor 95 are provided in the third suction pipe 63. The first discharge tube 64 is provided with a first discharge temperature sensor 97 and a first discharge pressure sensor 98. Each of the branch pipes 64a and 64b of the first discharge pipe 64 is provided with one high-pressure pressure switch 96. The second discharge tube 65 is provided with a second discharge temperature sensor 99 and a high pressure switch 96.

In addition, the outdoor unit 11 is provided with an outdoor temperature sensor 90 and an outdoor fan 48. The outdoor air is sent to the outdoor heat exchanger 44 by the outdoor fan 48.

<Air conditioning unit>

The air conditioning unit 12 constitutes a use unit. The air conditioning unit 12 includes an air conditioning circuit 100. The air conditioning circuit 100 has a liquid end connected to the second liquid side communication pipe 22 and a gas end connected to the second gas side communication pipe 24, respectively.

In the air conditioning circuit 100, an air conditioning expansion valve 102 and an air conditioning heat exchanger 101 are provided in turn from the liquid end to the gas end. The air conditioning heat exchanger 101 is a cross fin fin tube heat exchanger. In the air conditioning heat exchanger (101), heat exchange is performed between the refrigerant and the indoor air. On the other hand, the air conditioning expansion valve 102 is constituted by an electromagnetic expansion valve.

The air conditioning unit 12 is provided with a heat exchanger temperature sensor 103 and a refrigerant temperature sensor 104. The heat exchanger temperature sensor 103 is installed in the heat transfer tube of the air conditioning heat exchanger 101. The coolant temperature sensor 104 is installed near the gas end of the air conditioning circuit 100. In addition, the air conditioning unit 12 is provided with a temperature sensor 106 and an air conditioning fan 105. The air conditioning fan 105 sends indoor air in the store to the air conditioning heat exchanger 101.

<Cold Showcase>

The refrigerated showcase 13 constitutes a use unit. The refrigeration showcase 13 has a refrigeration circuit (110). The refrigeration circuit 110 has a liquid end connected to the second liquid side communication pipe 22 and a gas end connected to the first gas side communication pipe 23, respectively.

In the refrigerating circuit 110, the refrigerating solenoid valve 114, the refrigerating expansion valve 112, and the refrigerating heat exchanger 111 are provided in order from the liquid end to the gas end. The refrigerated heat exchanger 101 is a cross fin fin tube type heat exchanger. In the refrigerated heat exchanger (111), heat exchange occurs between the refrigerant and the air in the refrigerator. The refrigeration expansion valve 112 is constituted by a temperature automatic expansion valve. The temperature reduction tube 113 of the refrigerating expansion valve 112 is installed at an outlet side pipe of the refrigerating heat exchanger 111.

The refrigeration showcase 13 is provided with a temperature sensor 116 in the refrigerator and a fan 115 in the refrigerator. In the refrigerator heat exchanger 111, the air in the refrigerator of the refrigerator cabinet 13 is sent by the fan 115 in the refrigerator.

<Frozen showcase>

The freezing showcase 14 constitutes a use unit. The refrigeration showcase 14 has a refrigeration circuit (130). The refrigeration circuit 130 has a liquid end connected to the second liquid side communication pipe 22. The gas end of the refrigerating circuit 130 is connected to the booster unit 15 via a pipe.

In the refrigerating circuit 130, the refrigerating solenoid valve 134, the refrigerating expansion valve 132, and the refrigerating heat exchanger 131 are provided in order from the liquid end to the gas end. The refrigeration heat exchanger 131 is a cross fin fin tube heat exchanger. In the refrigeration heat exchanger 131, heat exchange is performed between the refrigerant and the air in the freezer. Refrigeration expansion valve 132 is configured by a temperature automatic expansion valve. The temperature reduction tube 133 of the refrigeration expansion valve 132 is installed in the outlet side pipe of the refrigerated heat exchanger (131).

The freezer showcase 14 is provided with a freezer temperature sensor 136 and a freezer fan 135. Air in the freezer of the freezer showcase 14 is sent to the freezer heat exchanger 131 by the freezer fan 135.

<Booster Unit>

The booster unit 15 includes a booster circuit 140. The booster circuit 140 includes a booster compressor 141, a suction pipe 143, a discharge pipe 144, and a bypass pipe 150.

The booster compressor 141 is a hermetic and high pressure dome scroll compressor. The booster compressor 141 is supplied with power through an inverter. The booster compressor 141 is configured such that its capacity can be changed by changing the output frequency of the inverter to change the rotational speed of the compressor motor.

The suction pipe 143 has an end thereof connected to the suction side of the booster compressor 141. The start end of the suction pipe 143 is connected to the gas side end of the refrigerating circuit 130 via a pipe.

The discharge tube 144 has its start end connected to the discharge side of the booster compressor 141 and the end connected to the first gas side communication pipe 23, respectively. The discharge pipe 144 is provided with a high pressure switch 148, an oil separator 145, and a discharge side check valve 149 in order from the start end to the end. The discharge side check valve 149 allows only the circulation of the refrigerant from the start end to the end of the discharge pipe 144.

The oil separator 145 separates the refrigeration oil from the discharge gas of the booster compressor 141. One end of the oil return pipe 146 is connected to the oil separator 145. The other end of the oil return pipe 146 is connected to the suction pipe 143. The oil return pipe 146 is provided with a capillary tube 147. The refrigeration oil separated from the oil separator 145 is returned to the suction side of the booster compressor 141 through the oil return pipe 146.

The bypass pipe 150 has a start end connected to the suction pipe 143 and an end connected between the oil separator 145 of the discharge pipe 64 and the discharge check valve 149. The bypass pipe 150 is provided with a bypass check valve 141 that allows only the flow of the refrigerant from the start end to the end.

<Super Cooling Unit>

The subcooling unit 200 as the subcooling apparatus includes a refrigerant passage 205, a subcooling refrigerant circuit 220, a subcooling heat exchanger 210, and a controller 240.

One end of the refrigerant passage 205 is connected to the first liquid side communication pipe 21, and the other end thereof to the second liquid side communication pipe 22.

The subcooling refrigerant circuit 220 is configured by connecting the subcooling compressor 221, the subcooling outdoor heat exchanger 222, the subcooling expansion valve 223, and the subcooling heat exchanger 210 in sequence. It is a closed circuit. This subcooling refrigerant circuit 220 constitutes a cooling fluid circuit. The subcooling refrigerant circuit 220 is filled with a subcooling refrigerant as a cooling fluid. As the supercooling refrigerant, various refrigerants such as carbon dioxide (CO2) and ammonia, as well as so-called freon refrigerants such as R407C, can be used. In this subcooling refrigerant circuit 220, the freezing circulation is achieved by circulating the charged subcooling refrigerant.

The subcooling compressor 221 is a hermetic and high pressure dome scroll compressor. Power is supplied to the subcooling compressor 221 through an inverter. The subcooling compressor 221 is configured such that its capacity can be changed by changing the output frequency of the inverter to change the rotational speed of the compressor motor. The subcooled outdoor heat exchanger 222 is a cross fin fin tube type heat exchanger. In this subcooling outdoor heat exchanger 222, heat exchange is performed between the subcooling refrigerant and outdoor air. The subcooled expansion valve 223 is constituted by an electromagnetic expansion valve.

The supercooling heat exchanger 210 is composed of a so-called plate heat exchanger. A plurality of first flow passages 211 and second flow passages 212 are formed in the subcooling heat exchanger 210. The subcooling refrigerant circuit 220 is connected to the first flow passage 211, and the refrigerant passage 205 is connected to the second flow passage 212, respectively. The subcooling heat exchanger 210 heat-exchanges the refrigerant for subcooling flowing through the first flow passage 211 and the refrigerant in the refrigerating device 10 flowing through the second flow passage 212.

The subcooling unit 200 is also provided with various sensors and pressure switches. Specifically, in the subcooling refrigerant circuit 220, the suction temperature sensor 235 and the suction pressure sensor 234 are installed on the suction side of the subcooling compressor 221, and the discharge temperature sensor () on the discharge side of the subcooling compressor 221. 233 and a high pressure switch 232 are installed. In the coolant passage 205, a coolant temperature sensor 236 is provided at the other end portion, that is, at the end portion connected to the second liquid side communication pipe 22, than the supercooling heat exchanger 210. This refrigerant temperature sensor 236 constitutes a refrigerant temperature detecting means.

In addition, the subcooling unit 200 is provided with an outside air temperature sensor 231 and an outdoor fan 230. The outdoor air is sent to the subcooled outdoor heat exchanger 222 by the outdoor fan 230.

The controller 240 constitutes a control means. The controller 240 inputs a detection value of the refrigerant temperature sensor 236, a detection value of the suction pressure sensor 234, and a detection value of the outside air temperature sensor 231. The controller 240 is configured to control the starting and stopping of the subcooling compressor 221 based on the detected value of the input sensor. The controller 240 does not receive any signal from the refrigerating device 10 composed of the outdoor unit 11, the air conditioning unit 12, or the like. That is, the controller 240 controls the operation of the subcooling compressor 221 based only on information obtained inside the subcooling unit 200, such as a detection value of a sensor installed in the subcooling unit 200.

Operation of refrigeration system

The main operation of the operation performed by the refrigeration system will be described.

<Cooling operation>

The cooling operation is an operation of cooling the air in the refrigerator and the freezer in the refrigerated showcase 13 and the freezing showcase 14, and cooling the indoor air in the air conditioning unit 12 to cool the inside of the store.

As shown in FIG. 2, during the cooling operation, the first four-way switching valve 51, the second four-way switching valve 52, and the third four-way switching valve 53 are set to the first state, respectively. In addition, the outdoor expansion valve 46 is completely closed, while the openings of the air conditioning expansion valve 102, the refrigeration expansion valve 112, and the freezing expansion valve 132 are appropriately adjusted. In this state, the variable displacement compressor 41, the first fixed displacement compressor 42, the second fixed displacement compressor 43, and the booster compressor 141 are operated. During this cooling operation, the subcooling unit 200 enters the operation state. The operation of the subcooling unit 200 will be described later.

The refrigerant discharged from the variable capacity compressor (41), the first fixed capacity compressor (42), and the second fixed capacity compressor (43) is sent to the outdoor heat exchanger (44) through the first four-way switching valve (51). Lose. In the outdoor heat exchanger (44), the refrigerant radiates heat to the outdoor air to condense. The refrigerant condensed in the outdoor heat exchanger (44) passes through the first liquid pipe (81), the receiver (45), and the second liquid pipe (82) in order and flows into the first liquid side communication pipe (21).

The refrigerant introduced into the first liquid side communication pipe 21 flows into the refrigerant passage 205 of the subcooling unit 200. The refrigerant introduced into the refrigerant passage 205 is cooled while passing through the second flow passage 212 of the subcooling heat exchanger 210. The liquid refrigerant in the subcooled state cooled by the subcooling heat exchanger 210 passes through the second liquid side communication pipe 22 and is distributed to the air conditioning circuit 100, the refrigerating circuit 110, and the refrigerating circuit 130.

The refrigerant introduced into the air conditioning circuit 100 is reduced in pressure when passing through the air conditioning expansion valve 102, and then introduced into the air conditioning heat exchanger 101. In the air conditioning heat exchanger (101), the refrigerant absorbs heat from the room air and evaporates. At this time, in the air conditioning heat exchanger 101, the evaporation temperature of the refrigerant is set to, for example, about 5 ° C. In the air conditioning unit 12, indoor air cooled by the air conditioning heat exchanger 101 is supplied into the shop.

After the refrigerant evaporated from the air conditioning heat exchanger (101) flows into the outdoor circuit (40) through the second gas side communication pipe (24), the first four-way switching valve (51) and the second four-way switching valve (52). Passes in order to flow into the third suction pipe (63). A portion of the refrigerant introduced into the third suction pipe 63 passes through the first branch pipe 63a and is sucked into the second fixed displacement compressor 43, and the rest of the refrigerant flows into the second branch pipe 63b and the third cross. It passes through the switching valve 53 and the second suction pipe 62 in order to be sucked into the first fixed displacement compressor 42.

The refrigerant introduced into the refrigerating circuit 110 is reduced in pressure when passing through the refrigerating expansion valve 112, and then introduced into the refrigerating heat exchanger 111. In the refrigerating heat exchanger (111), the refrigerant absorbs heat from the air in the refrigerator and evaporates. At this time, in the refrigerating heat exchanger 111, the evaporation temperature of the refrigerant is set to, for example, about -5 ° C. The refrigerant evaporated in the refrigerated heat exchanger (111) flows into the first gas side communication pipe (23). In the refrigerator showcase 13, the air in the refrigerator cooled by the refrigerator heat exchanger 111 is supplied into the refrigerator, and the temperature in the refrigerator is maintained at, for example, about 5 ° C.

The refrigerant introduced into the refrigerating circuit 130 is reduced in pressure when passing through the refrigerating expansion valve 132, and then introduced into the refrigerating heat exchanger 131. In the freezing heat exchanger (131), the refrigerant absorbs heat from the freezer air and evaporates. At this time, in the refrigeration heat exchanger 131, the evaporation temperature of the refrigerant is set to, for example, about -30 ° C. In the freezer showcase 14, the air in the freezer cooled by the freezer heat exchanger 131 is supplied into the freezer, and the freezer temperature is maintained at, for example, about -20 ° C.

The refrigerant evaporated in the refrigeration heat exchanger 131 flows into the booster circuit 140 and is sucked into the booster compressor 141. The refrigerant compressed by the booster compressor 141 flows into the first gas side communication pipe 23 through the discharge pipe 144.

In the first gas side communication pipe 23, the refrigerant introduced from the refrigerating circuit 110 and the refrigerant introduced from the booster circuit 140 join. These refrigerants then flow into the first suction pipe 61 of the outdoor circuit 40 through the first gas-side communication pipe 23. The refrigerant flowing into the first suction pipe 61 is sucked into the variable displacement compressor 41 after passing through the first branch pipe 61a.

<1st heating operation>

The first heating operation is an operation of cooling the air in the refrigerator and the freezer in the refrigerating showcase 13 and the freezing showcase 14 and heating the indoor air in the air conditioning unit 12 to heat the inside of the store.

As shown in Fig. 3, in the outdoor circuit 40, the first four-way switching valve 51 is in the second state, the second four-way switching valve 52 is in the first state, and the third four-way switching valve 53 is Each is set to the first state. In addition, while the outdoor expansion valve 46 is completely closed, the opening degree of the air conditioning expansion valve 102, the refrigeration expansion valve 112, and the freezing expansion valve 132 is appropriately adjusted. In this state, the variable displacement compressor 41 and the booster compressor 141 are operated, and the first fixed displacement compressor 42 and the second fixed displacement compressor 43 are at rest. In addition, the outdoor heat exchanger 44 is not supplied with the refrigerant, and is brought to rest. During this first heating operation, the subcooling unit 200 is stopped.

The refrigerant discharged from the variable capacity compressor (41) is introduced into the air conditioning heat exchanger (101) of the air conditioning circuit (100) by passing through the first four way switching valve (51) and the second gas side communication pipe (24) in order. It condenses by radiating heat to indoor air. In the air conditioning unit 12, indoor air heated in the air conditioning heat exchanger 101 is supplied into the shop. The refrigerant condensed in the air conditioning heat exchanger (101) passes through the second liquid side communication pipe (22) and is distributed to the refrigerating circuit (110) and the freezing circuit (130).

In the cold showcase 13 and the freezer showcase 14, the air in the refrigerator and the freezer is cooled as in the cooling operation. The refrigerant introduced into the refrigerating circuit 110 flows into the first gas side communication pipe 23 after evaporating in the refrigerating heat exchanger 111. Meanwhile, the refrigerant introduced into the refrigeration circuit 130 is compressed in the booster compressor 141 after evaporating in the refrigeration heat exchanger 131, and then flows into the first gas side communication pipe 23. The refrigerant introduced into the first gas side communication pipe 23 is sucked into the variable displacement compressor 41 after being passed through the first suction pipe 61 and compressed.

As described above, in the first heating operation, the refrigerant absorbs heat in the refrigerating heat exchanger 111 and the refrigeration heat exchanger 131, and the refrigerant radiates heat in the air conditioning heat exchanger 101. In the cold storage heat exchanger 111 and the freezing heat exchanger 131, the refrigerant is heated in the store by using endotherms from the air in the refrigerator and the freezer.

In addition, during the first heating operation, as shown in FIG. 4, the first fixed displacement compressor 42 may be operated. Whether or not to operate the first fixed capacity compressor 42 is determined in accordance with the cooling loads of the refrigerated showcase 13 and the refrigerated showcase 14. In this case, the third four-way switching valve 53 is set to the second state. A portion of the refrigerant introduced into the first suction pipe 61 passes through the first branch pipe 61a and is sucked into the variable displacement compressor 41, and the rest of the refrigerant flows through the second branch pipe 61b and the third cross switching. It passes through the valve 53 and the second suction pipe 62 in order to be sucked into the first fixed displacement compressor 42.

<2nd heating operation>

2nd heating operation is operation | movement which heats in a store similarly to said 1st heating operation. This second heating operation is performed when the heating capacity is insufficient in the first heating operation.

As shown in FIG. 5, in the outdoor circuit 40, the first four-way switching valve 51 is in the second state, the second four-way switching valve 52 is in the first state, and the third four-way switching valve 53 is closed. Each is set to the first state. Moreover, the opening degree of the outdoor expansion valve 46, the air conditioning expansion valve 102, the refrigeration expansion valve 112, and the refrigeration expansion valve 132 is appropriately adjusted. In this state, the variable displacement compressor 41, the second fixed displacement compressor 43, and the booster compressor 141 are operated, and the first fixed displacement compressor 42 is at rest. During this first heating operation, the subcooling unit 200 is stopped.

The refrigerant discharged from the variable capacity compressor (41) and the second fixed capacity compressor (43) pass sequentially through the first four-way switching valve and the second gas side communication pipe (24) to the air conditioning heat exchanger (101) of the air conditioning circuit. It is introduced and condensed by radiating heat to indoor air. In the air conditioning unit 12, indoor air heated in the air conditioning heat exchanger 101 is supplied into the shop. The refrigerant condensed in the air conditioning heat exchanger 101 flows into the second liquid side communication pipe 22. A portion of the refrigerant introduced into the second liquid side communication pipe 22 is distributed to the refrigerating circuit 110 and the refrigeration circuit 130, and the remainder is introduced into the refrigerant passage 205 of the subcooling unit 200.

In the cold showcase 13 and the freezer showcase 14, the air in the refrigerator and the freezer is cooled as in the cooling operation. The refrigerant introduced into the refrigerating circuit 110 flows into the first gas side communication pipe 23 after evaporating in the refrigerating heat exchanger 111. Meanwhile, the refrigerant introduced into the refrigeration circuit 130 is compressed in the booster compressor 141 after evaporating in the refrigeration heat exchanger 131, and then flows into the first gas side communication pipe 23. The refrigerant introduced into the first gas side communication pipe 23 is sucked into the variable displacement compressor 41 after being passed through the first suction pipe 61 and compressed.

The refrigerant flowing into the refrigerant passage 205 of the subcooling unit 200 passes through the first liquid side communication pipe 21 and the third liquid pipe 83 in order and flows into the receiver 45, and then the second liquid pipe ( It passes through 82 and flows into the fourth liquid pipe 84. The refrigerant flowing into the fourth liquid pipe 84 is depressurized when passing through the outdoor expansion valve 46, and then introduced into the outdoor heat exchanger 44 to endotherm and evaporate from the outdoor air. The refrigerant evaporated in the outdoor heat exchanger (44) passes through the first four-way switching valve (51) and the second four-way switching valve (52) in order to flow into the second suction pipe (62), and the second fixed displacement compressor (43). Inhaled and compressed.

In this manner, in the second heating operation, the refrigerant absorbs heat in the refrigerating heat exchanger 111, the refrigeration heat exchanger 131, and the outdoor heat exchanger 44, and the refrigerant radiates heat in the air conditioning heat exchanger 101. In the cold storage heat exchanger (111) and the freezing heat exchanger (131), the heat absorbed by the refrigerant from the air in the refrigerator and the freezer and the heat absorbed by the refrigerant from the outdoor air in the outdoor heat exchanger (44) are used for heating in the store. Is done.

Subcooling Unit of  Operation

The operation of the subcooling unit 200 will be described. In the operating state of the subcooling unit 200, the subcooling compressor 221 is operated, and the opening degree of the subcooling expansion valve 223 is appropriately adjusted.

As shown in FIG. 1, the subcooling refrigerant discharged from the subcooling compressor 221 condenses by radiating heat to outdoor air in the subcooling outdoor heat exchanger 222. The subcooled refrigerant condensed in the subcooled outdoor heat exchanger 222 is depressurized when passing through the subcooled expansion valve 223, and then flows into the first flow path 211 of the subcooled heat exchanger 210. In the first flow passage 211 of the subcooling heat exchanger 210, the supercooling refrigerant absorbs heat from the refrigerant of the second flow passage 212 and evaporates. The subcooling refrigerant evaporated by the subcooling heat exchanger 210 is sucked into the subcooling compressor 221 and compressed.

As described above, the controller 240 controls the start and stop of the subcooling compressor 221 based on the detected value of the sensor. Here, the control operation of the controller 240 will be described with reference to FIG. 6. The control operation of the controller 240 is repeatedly executed at a predetermined time interval (for example, at 10 second intervals).

First, in step ST10, it is judged whether the subcooling compressor 221 is running or stopped.

If it is determined in step ST10 that the subcooling compressor 221 is in operation, the process proceeds to step ST11. In step ST11, it is determined whether a predetermined time (for example, 2 minutes) has elapsed at the time when the subcooling compressor 221 is started. If a predetermined time has elapsed at the start of the subcooling compressor 221, the flow advances to step ST12. On the other hand, if the predetermined time has not elapsed, the process moves to step ST14 to end the control operation once, and the operation of the subcooling compressor 221 is continued.

In step ST12, a determination is made as to whether or not the subcooling compressor 221 is stopped. In this step ST12, it is determined whether the following four conditions are satisfied. If any one of these four conditions is satisfied, the flow advances to step ST13 to stop the subcooling compressor 221. On the other hand, if all four of these conditions are not satisfied, the process moves to step ST14 to end the control operation once, and the operation of the subcooling compressor 221 is continued.

The first condition of step ST12 will be described. This first condition is a condition for determining whether or not the detected value of the refrigerant temperature sensor 236 smoothly decreases after the subcooling compressor 221 is started.

In order to satisfy the first condition of step ST12, it is necessary to satisfy the following six requirements. The first requirement is that the detected value Ta of the outside temperature sensor 231 is less than 20 ° C (Ta <20). The second requirement is the refrigerant temperature sensor 236 detected value Tout_0 at the start of the subcooling compressor 221 and the refrigerant temperature sensor 236 detected value Tout_1 after 1 minute has elapsed since the subcooling compressor 221 is started. ) Is 3 degrees C or less (Tout_0-Tout_1≤3). The third requirement is the refrigerant temperature sensor 236 detected value Tout_0 at the start of the subcooling compressor 221 and the refrigerant temperature sensor 236 detected value Tout_2 two minutes after the subcooling compressor 221 is started. ) Is 5 degrees C or less (Tout_0-Tout_2≤5). The fourth requirement is the refrigerant temperature sensor 236 detected value Tout_0 at the start of the subcooling compressor 221 and the refrigerant temperature sensor 236 detected value Tout_3 after 3 minutes from the start of the subcooling compressor 221. ) Is 7 degrees C or less (Tout_0-Tout_3≤7). The fifth requirement is that three minutes have already elapsed at the start of the subcooling compressor 221. The sixth requirement is that the refrigerant temperature sensor 236 operates normally.

When all of the first to sixth requirements are satisfied, the detected value of the refrigerant temperature sensor 236 is achieved even though the temperature of the outdoor air is not so high that the cooling capacity of the supercooling heat exchanger 210 is sufficiently obtained. (Tout) is a state that does not deteriorate very much. Thus, when the first condition of the step ST12 is satisfied, the refrigerant does not flow in the refrigerant passage 205 as in the first heating operation, or the outdoor unit inside the refrigerant passage 205 as in the second heating operation. It can be determined that the coolant is flowing toward (11). Thus, when the first condition is satisfied, the controller 240 determines that the refrigerating device 10 is in an operation state that does not require the operation of the subcooling unit 200, and stops the subcooling compressor 221.

The second condition of step ST12 will be described. This second condition is a condition for determining whether the detected value of the refrigerant temperature sensor 236 has become a valid value corresponding to the evaporation temperature of the subcooling refrigerant during operation of the subcooling compressor 221.

In order to satisfy the second condition of step ST12, it is necessary to satisfy the following four requirements. The first requirement is that 5 minutes have already elapsed from the start of the subcooling compressor 221. The second requirement is that the detected value Tout of the refrigerant temperature sensor 236 is larger than the sum of the evaporation temperature Tg of the subcooling coolant in the subcooling heat exchanger 220 plus 15 (Tout> Tg + 15). ) The third requirement is that the refrigerant temperature sensor 236 has operated normally. The fourth requirement is that the suction pressure sensor 234 has operated normally.

Here, the controller 240 regards the supercooled refrigerant saturation temperature of the suction pressure sensor 234 detected value LP as the evaporation temperature Tg of the supercooled refrigerant. That is, in this embodiment, the evaporation temperature detection means which detects the evaporation temperature of the supercooling refrigerant | coolant is comprised by the suction pressure sensor 234. As shown in FIG.

When all of the first to fourth requirements are satisfied, although the refrigeration circulation is performed in the subcooling refrigerant circuit 220, the detected value Tout of the refrigerant temperature sensor 236 and the evaporation temperature of the subcooling refrigerant ( The difference with Tg) is in a state larger than 15 ° C. Thus, even when the second condition of step ST12 is satisfied, the refrigerant does not flow in the refrigerant passage 205 as in the first heating operation, or outdoor in the refrigerant passage 205 as in the second heating operation. It may be determined that the coolant is flowing toward the unit 11. Thus, when this second condition is satisfied, the controller 240 determines that the refrigerating device 10 is in an operating state that does not require the operation of the subcooling unit 200, and stops the subcooling compressor 221.

The third condition of step ST12 will be described. The third condition is satisfied when the detected value LP of the suction pressure sensor 234 is less than 0.2 MPa and the suction pressure sensor 234 is in an abnormal state. In this case, since the detection value of the suction pressure sensor 234 is not normal, the operation of the subcooling compressor 221 cannot be properly controlled based on this. Thus, if the third condition is satisfied, the controller 240 stops the subcooling compressor 221.

The fourth condition of step ST12 will be described. This fourth condition is satisfied when the detection value LP of the suction pressure sensor 234 is less than 0.15 MPa. In this case, the detection value of the suction pressure sensor 234 is such a low value that it cannot exist in a normal operation state. Thus, when the fourth condition is satisfied, the controller 240 determines that a problem has occurred and stops the subcooling compressor 221.

If it is determined in step ST10 that the subcooling compressor 221 is stopped, the process moves to step ST15. In step ST15, it is determined whether a predetermined time has elapsed at the time of stopping the subcooling compressor 221. In order to avoid repeating the start and stop of the subcooling compressor 221 in a short time, once the subcooling compressor 221 is stopped, the subcooling compressor ( Limit the restart of 221). In step ST15, if a predetermined time has not elapsed from the stop point of the subcooling compressor 221, the process moves to step ST14 to end the control operation once, and the subcooling compressor 221 is kept in a stopped state. On the other hand, if a predetermined time has elapsed when the subcooling compressor 221 stops, the process proceeds to step ST16.

In step ST16, a determination is made as to whether or not the subcooling compressor 221 is started. In this step ST16, it is determined whether the following three conditions are satisfied. If any one of these three conditions is satisfied, the process advances to step ST17 to start the subcooling compressor 221. On the other hand, if all three of these conditions are not satisfied, the process moves to step ST14 to end the control operation once and to keep the subcooling compressor 221 in the stopped state.

The first condition of step ST16 will be described. The first condition is satisfied when the detected value Ta of the outside air temperature sensor 231 is 25 ° C. or more and already one minute has elapsed since the stop of the subcooling compressor 221. In this case, although the outdoor air is very high temperature, the subcooling compressor 221 is stopped for 1 minute or more. Thus, when the first condition is satisfied, the controller 240 starts the subcooling compressor 221 to cool the refrigerant in the refrigerant passage 205.

The second condition of step ST16 will be described. This second condition is satisfied when the detected value Ta of the outside air temperature sensor 231 is 20 ° C or more and already 3 minutes has elapsed from the stop point of the subcooling compressor 221. In this case, although the outdoor air is relatively high, the subcooling compressor 221 is stopped for three minutes or more. Thus, when the second condition is satisfied, the controller 240 starts the subcooling compressor 221 to cool the refrigerant in the refrigerant passage 205.

The third condition of step ST16 will be described. The third condition is satisfied when 10 minutes have already passed from the stop point of the subcooling compressor 221. In this case, the subcooling compressor 221 is stopped for a relatively long time. Thus, when the third condition is satisfied, the controller 240 starts the subcooling compressor 221 to cool the refrigerant in the refrigerant passage 205. In this way, when the stop time of the subcooling compressor 221 reaches 10 minutes or more, the controller 240 always starts the subcooling compressor 221.

Effect of Embodiments

In the subcooling unit 200, the controller 240 controls the operation of the subcooling compressor 221 based only on information obtained in the subcooling unit 200, such as a detection value of a sensor installed in the subcooling unit 200. That is, in this subcooling unit 200, it is possible to control the operation of the subcooling compressor 221 according to the operation state of the refrigerating device 10 even if no signal is exchanged with the refrigerating device 10. Thus, when the subcooling unit 200 is installed in the refrigerating device 10, the refrigerant passage 205 of the subcooling unit 200 is connected to the first and second liquid side communication pipes 21 and 22 of the refrigerating device 10. It only needs to be connected, and there is no need to lay communication wiring for exchanging signals between the refrigerating device 10 and the subcooling unit 200.

Therefore, according to this embodiment, the number of work processes at the time of installing the subcooling unit 200 to the refrigerating device 10 can be reduced, and the problem resulting from human work errors at the time of installation work, such as a wiring error, is prevented beforehand. can do.

Here, in order to exchange signals between the subcooling unit 200 and the refrigerating device 10, a communication interface is required for the refrigerating device 10 as well as the subcooling unit 200. Therefore, for the subcooling unit 200 which requires a signal input from the freezing device 10 for operation control, the model of the applicable freezing device 10 is limited, and the problem that the use of the subcooling unit 200 is inconvenient also occurs. there was.

In contrast, the subcooling unit 200 of the present embodiment does not require any signal transmission between the refrigerating device 10 and is not restricted by the refrigerating device 10 to be installed. Therefore, according to this embodiment, the model restriction of the refrigerating device 10 to be installed of the subcooling unit 200 can be eliminated, and the usability of the subcooling unit 200 can be greatly improved.

First embodiment Variant -

In the subcooling unit 200 of the present embodiment, temperature sensors 237 and 238 are provided on both sides of the subcooling heat exchanger 210 of the refrigerant passage 205 and based on the detected values of these temperature sensors 237 and 238. The operation of the subcooling compressor 221 may be controlled.

As shown in FIG. 7, in the refrigerant passage 205, the first refrigerant temperature sensor is disposed at a portion at the other end than the subcooling heat exchanger 210, that is, at the portion connected to the second liquid side communication pipe 22. 237 is installed. In the refrigerant passage 205, the second refrigerant temperature sensor 238 is provided at one end portion, that is, at the end portion connected to the first liquid side communication pipe 21, than the subcooling heat exchanger 210. . In this subcooling unit 200, the first refrigerant temperature sensor 237 constitutes the first refrigerant temperature detection means, and the second refrigerant temperature sensor 238 constitutes the second refrigerant temperature detection means.

The detected value of the first refrigerant temperature sensor 237 and the detected value of the second refrigerant temperature sensor 238 are input to the controller 240 of the present modification. The controller 240 contrasts the detection values of the two refrigerant temperature sensors 237 and 238 during the operation of the subcooling compressor 221 and determines whether to continue or stop the operation of the subcooling compressor 221 according to the result. It is composed.

The control operation of this controller 240 will be described.

First, when the detection value of the first refrigerant temperature sensor 237 is lower than the detection value of the second refrigerant temperature sensor 238 during the operation of the subcooling compressor 221, the refrigerant cooled in the subcooling heat exchanger 210 is performed. The temperature is detected by the first refrigerant temperature sensor 237. Therefore, in this case, for example, it can be determined that the refrigerant flows in the refrigerant passage 205 from the first liquid side communication pipe 21 toward the second liquid side communication pipe 22 side as in the cooling operation, so that the controller ( 240 continues the operation of the subcooling compressor 221.

On the other hand, if the detection value of the second refrigerant temperature sensor 238 is lower than the detection value of the first refrigerant temperature sensor 237 during the operation of the subcooling compressor 221, the refrigerant cooled in the subcooling heat exchanger 210. The temperature is detected by the second refrigerant temperature sensor 238. Therefore, in this case, for example, it can be determined that the refrigerant flows in the refrigerant passage 205 from the second liquid side communication pipe 22 side toward the first liquid side communication pipe 21 side as in the second heating operation. The controller 240 stops the operation of the subcooling compressor 221.

If the detected value of the first refrigerant temperature sensor 237 and the detected value of the second refrigerant temperature sensor 238 are substantially the same during the operation of the supercooling compressor 221, the refrigerant passage (for example, during the first heating operation) It can be determined that the refrigerant is not circulated in the 205, and the controller 240 stops the operation of the subcooling compressor 221.

Here, in the controller 240 of the present modification, the difference between the detected value of the first refrigerant temperature sensor 237 and the detected value of the second refrigerant temperature sensor 238 is a distribution indicating the refrigerant circulation state of the refrigerant passage 205. It may be used as a status display value. That is, when the value obtained by subtracting the detection value of the second refrigerant temperature sensor 238 from the detection value of the first refrigerant temperature sensor 237 is negative, the detection value of the first refrigerant temperature sensor 237 is the second refrigerant temperature sensor 238. The controller 240 continues the operation of the subcooling compressor 221 because it may be determined to be lower than the detected value. If the value obtained by subtracting the detection value of the second refrigerant temperature sensor 238 from the detection value of the first refrigerant temperature sensor 237 is zero or more, the detection value of the first refrigerant temperature sensor 237 is the second refrigerant temperature sensor 238. The controller 240 stops the subcooling compressor 221 because it may be determined to be higher than the detected value or both are the same.

-Second of embodiment Variant -

In the subcooling unit 200 of the present embodiment, as shown in FIG. 8, a flowmeter 250 is provided in the refrigerant passage 205, and the compressor for subcooling is based on the detected value of the flowmeter 251. 221 may be controlled to drive.

In this subcooling unit 200, the detection value of the flowmeter 251 is input to the controller 240. The controller 240 determines whether the refrigerant flows in the refrigerant passage 205 and whether the refrigerant flows in the refrigerant passage 205 based on the detected value of the flowmeter. In other words, the controller 240 uses the detected value of the flow meter 251 as the flow state display value indicating the coolant flow state in the coolant passage 205.

When it is determined that the refrigerant flows in the refrigerant passage 205 from the first liquid side communication pipe 21 toward the second liquid side communication pipe 22 side during the operation of the subcooling compressor 221, the controller 240 performs subcooling. The operation of the compressor 221 is continued. In the case where it is determined that the refrigerant flows in the refrigerant passage 205 from the second liquid side communication pipe 22 toward the first liquid side communication pipe 21 side during the operation of the subcooling compressor 221, or the subcooling compressor If it is determined that the refrigerant does not flow in the refrigerant passage 205 during the operation of 221, the controller 240 stops the operation of the subcooling compressor 221.

Third of embodiment Variant -

In the controller 240 of the present embodiment, the operation of the subcooling compressor 221 may be controlled based only on the detected value of the outside air temperature sensor 231.

The operation of the controller 240 will be described. When the detected value of the outside air temperature sensor 231 exceeds a predetermined upper limit value (for example, 30 ° C.), the cooling load in the refrigeration showcase 13 or the freezing showcase 14 or the cooling load in the air conditioning unit 12 is reduced. It can be assumed to be high. Thus, in such a case, the controller 240 starts the subcooling compressor 221 if the subcooling compressor 221 is stopped, and stops the operation of the subcooling compressor 221 if the subcooling compressor 221 is in operation. Continue. The refrigerant flowing in the refrigerant passage 205 from the first liquid side communication pipe 21 toward the second liquid side communication pipe 22 is cooled by the subcooling heat exchanger 210 and then supplied to the refrigerating showcase 13 or the like. do.

On the other hand, when the detected value of the outside air temperature sensor 231 is below the predetermined lower limit value (for example, 20 ° C), the cooling load in the refrigerated showcase 13 or the freeze showcase 14 or the air conditioner unit 12 is cooled. It can be assumed that the load is lowered, and it is determined that the operation of the subcooling compressor 221 is not necessary. Thus, in such a case, the controller 240 stops the subcooling compressor 221 if the subcooling compressor 221 is stopped, and the subcooling compressor 221 if the subcooling compressor 221 is in operation. Stop it.

Fourth embodiment Variant -

In the controller 240 of the present embodiment, the operation of the subcooling compressor 221 may be controlled based only on the change in the detection value of the refrigerant temperature detecting means 236. The controller 240 of the present modification uses the change in the detection value of the coolant temperature detecting means 236 as a flow state display value indicating the coolant flow state in the coolant passage 205.

The operation of the controller 240 will be described. When the detected value of the refrigerant temperature detecting means 236 gradually decreases from the time when the subcooling compressor 221 is started, the second liquid side communication pipe 21 is connected to the first liquid side communication pipe 21 in the refrigerant passage 205. It can be determined that the coolant flows toward (22). Thus, in this case, the controller 240 continues the operation of the subcooling compressor 221.

On the other hand, if the detected value of the refrigerant temperature detecting means 236 does not decrease even when the subcooling compressor 221 is started, the first liquid side communication pipe 22 is connected to the second liquid side communication pipe 22 in the refrigerant passage 205. It can be determined that the coolant is flowing toward (21) or the coolant is not flowing in the coolant passage 205. In this case, the controller 240 stops the subcooling compressor 221.

When the detected value of the refrigerant temperature detecting means 236 gradually increases from the time when the subcooling compressor 221 is stopped, the second liquid side communication is directed from the first liquid side communication pipe 21 to the inside of the refrigerant passage 205. It can be determined that the refrigerant flows toward the pipe 22. Thus, in this case, the controller 240 restarts the subcooling compressor 221.

On the other hand, when the detection value of the refrigerant temperature detecting means 236 does not rise even when the subcooling compressor 221 is stopped, the first liquid side communication pipe 22 is connected to the second liquid side communication pipe 22 in the refrigerant passage 205. It can be determined that the coolant is flowing toward (21) or the coolant is not flowing in the coolant passage 205. Thus, in such a case, the controller 240 keeps the subcooling compressor 221 stopped.

Fifth embodiment Variant -

In the controller 240 of the present embodiment, the operation of the subcooling compressor 221 may be controlled based on the subcooling refrigerant temperature difference between the inlet and the outlet of the subcooling heat exchanger 210 and the first flow path 211.

As shown in FIG. 9, the first subcooling refrigerant temperature sensor 252 and the second subcooling refrigerant temperature sensor 253 are provided in the subcooling unit 200 of the present modification. In the subcooling refrigerant circuit 220, the first subcooling refrigerant temperature sensor 252 is disposed in front of the first flow path 211 of the subcooling heat exchanger 210, and the subcooling refrigerant flows into the first flow path 211. The temperature of the refrigerant is detected. On the other hand, the second subcooling refrigerant temperature sensor 253 is disposed immediately after the first flow passage 211 of the subcooling heat exchanger 210, and detects the supercooling refrigerant temperature immediately after flowing out of the first flow passage 211. do. Then, the controller 240 of the present modification differs between the detected value of the first subcooled refrigerant temperature sensor 252 and the detected value of the second subcooled refrigerant temperature sensor 253 in the refrigerant passage 205. It is used as a distribution status display value indicating the status.

The operation of the controller 240 will be described. During operation of the subcooling compressor 221, when the detection value of the second subcooling refrigerant temperature sensor 253 is higher than the detection value of the first subcooling refrigerant temperature sensor 252 (that is, the second subcooling refrigerant temperature sensor). If the value obtained by subtracting the detection value of the first subcooling refrigerant temperature sensor 252 from the detection value of (253) is positive (+), the inside of the refrigerant passage 205 is formed from the first liquid side communication pipe 21 side. 2 It can be determined that the refrigerant flows toward the liquid-side communication pipe (22). Thus, in this case, the controller 240 continues the operation of the subcooling compressor 221.

On the other hand, during operation of the subcooling compressor 221, when the detection value of the second subcooling refrigerant temperature sensor 253 is lower than the detection value of the first subcooling refrigerant temperature sensor 252 or there is no difference (i.e., When the value obtained by subtracting the detection value of the first subcooling refrigerant temperature sensor 252 from the detection value of the second subcooling refrigerant temperature sensor 253 is zero or less), the second liquid-side communication piping is connected to the inside of the refrigerant passage 205. It can be determined that the refrigerant flows from the side (22) toward the first liquid side communication pipe 21 side, or the refrigerant does not flow in the refrigerant passage 205. In this case, the controller 240 stops the subcooling compressor 221.

Sixth Modification of Embodiments

In the controller 240 of the present embodiment, the operation of the subcooling compressor 221 may be controlled based only on the detection value of the suction pressure sensor 234. The detected value of the suction pressure sensor 234 becomes substantially equal to the refrigerant pressure in the first flow path 211 of the subcooling heat exchanger 210, that is, the evaporation pressure of the subcooling refrigerant. Therefore, in this modification, the suction pressure sensor 234 constitutes evaporation pressure detecting means. The controller 240 of the present modification uses the detection value of the suction pressure sensor 234 as a flow state display value indicating the coolant flow state of the coolant passage 205.

The operation of the controller 240 will be described. If the detected value of the suction pressure sensor 234 exceeds a predetermined reference value (for example, 0.2 MPa) during the operation of the subcooling compressor 221, the subcooling is performed in the first flow path 211 of the subcooling heat exchanger 210. Since the refrigerant is evaporated, it can be determined that the refrigerant flows in the refrigerant passage 205. Thus, in this case, the controller 240 continues the operation of the subcooling compressor 221.

On the other hand, when the detection value of the suction pressure sensor 234 is equal to or less than the reference value during the operation of the subcooling compressor 221, the subcooling refrigerant is hardly evaporated in the first flow path 211 of the subcooling heat exchanger 210. In this case, it can be determined that the refrigerant does not flow in the refrigerant passage 205. In this case, the controller 240 stops the subcooling compressor 221.

Seventh Modification of Embodiments

In the controller 240 of the present embodiment, the operation of the subcooling compressor 221 may be controlled based only on the difference between the detection value Tout of the refrigerant temperature sensor 236 and the evaporation temperature Ta of the subcooling refrigerant. The controller 240 of the present modification uses the difference between the detection value Tout of the refrigerant temperature sensor 236 and the evaporation temperature Tg of the supercooling refrigerant as a distribution state display value indicating the refrigerant circulation state of the refrigerant passage 205. I use it.

The operation of the controller 240 will be described. During operation of the subcooling compressor 221, the value obtained by subtracting the evaporation temperature Tg of the subcooling refrigerant from the detected value Tout of the refrigerant temperature sensor 236 becomes a predetermined reference value (for example, 15 ° C) or less. It can be determined that the refrigerant flows in the refrigerant passage 205 from the first liquid side contact pipe 21 toward the second liquid side communication pipe 22. Thus, in this case, the controller 240 continues the operation of the subcooling compressor 221.

On the other hand, during operation of the subcooling compressor 221, when the value obtained by subtracting the evaporation temperature Tg of the subcooling refrigerant from the detected value Tout of the refrigerant temperature sensor 236 is equal to or less than the reference value, the refrigerant passage 205. It can be determined that the refrigerant flows from the second liquid side communication pipe 22 side toward the first liquid side communication pipe 21 side or that no refrigerant flows in the refrigerant passage 205. In this case, the controller 240 stops the subcooling compressor 221.

-Eighth embodiment Variant -

In the controller 240 of the present embodiment, the operation of the subcooling compressor 221 may be controlled based only on the detection value of the refrigerant temperature detecting means 236. The controller 240 of the present modification uses the detected value of the coolant temperature detecting means 236 as a flow state display value indicating the coolant flow state of the coolant passage 205.

The operation of the controller 240 will be described. If the detected value of the refrigerant temperature detecting means 236 exceeds a predetermined reference value while the subcooling compressor 221 is stopped, the temperature of the refrigerant sent from the outdoor unit 11 to the use side of the refrigerating showcase 13 or the like is increased. It is estimated that the cooling capacity in the refrigerated showcase 13 and the like is slightly insufficient. In this case, the controller 240 starts the subcooling compressor 221.

On the other hand, when the detection value of the refrigerant temperature detecting means 236 is lower than or equal to a predetermined reference value while the subcooling compressor 221 is stopped, the refrigerant is sent from the outdoor unit 11 to the use side of the refrigerating showcase 13 or the like. The temperature of is not so high, it can be assumed that the cooling capacity in the refrigerating showcase 13 or the like is sufficiently secured. Thus, in such a case, the controller 240 keeps the subcooling compressor 221 stopped.

-Ninth embodiment Variant -

In the controller 240 of the present embodiment, the operation of the subcooling compressor 221 may be controlled based on the difference between the detected value of the refrigerant temperature sensor 236 and the detected value of the outside air temperature sensor 231. The controller 240 of the present modification uses the difference between the detected value of the refrigerant temperature detecting means 236 and the detected value of the outside air temperature sensor 231 as a distribution state display value indicating the refrigerant circulation state of the refrigerant passage 205. .

The operation of the controller 240 will be described. When the refrigerant flows in the refrigerant passage 205 from the first liquid side communication pipe 21 side toward the second liquid side communication pipe 22 side, the refrigerant condensed by radiating heat into the outdoor air in the outdoor heat exchanger 44 is the refrigerant passage. Although it flows into 205, the temperature of this refrigerant cannot be below the temperature of outdoor air. Thus, when the value obtained by subtracting the detection value of the outside temperature sensor 231 from the detection value of the refrigerant temperature detection means 236 during the stop of the subcooling compressor 221 exceeds the predetermined reference value, the inside of the refrigerant passage 205. It can be determined that the refrigerant flows from the first liquid side communication pipe 21 toward the second liquid side communication pipe 22. In this case, the controller 240 starts the subcooling compressor 221.

On the other hand, when the value obtained by subtracting the detection value of the outside air temperature sensor 231 from the detection value of the refrigerant temperature detecting means 236 during the stop of the subcooling compressor 221 becomes less than or equal to the predetermined reference value, the refrigerant passage 205. It can be determined that the refrigerant flows from the second liquid side communication pipe 22 toward the first liquid side communication pipe 21, or that the refrigerant does not flow in the refrigerant passage 205. Thus, in such a case, the controller 240 keeps the subcooling compressor 221 stopped.

-Tenth embodiment Variant -

In the subcooling unit 200 of the present embodiment, the subcooling refrigerant circuit 200 may be configured to allow natural circulation of the refrigerant.

As shown in FIG. 10, in the subcooling refrigerant circuit 220 of the present modification, the subcooling outdoor heat exchanger 222 is disposed above the subcooling heat exchanger 210. In addition, the bypass cooling circuit 220 is provided with a bypass pipe 224. The bypass pipe 224 has one end connected to the suction side of the subcooling compressor 221 and the other end to the discharge side of the subcooling compressor 221. In addition, the bypass pipe 224 is provided with a check valve 225 that allows only the flow of the refrigerant from one end to the other end.

In this subcooling refrigerant circuit 220, even when the subcooling compressor 221 is stopped, the subcooling refrigerant circulates by operating the outdoor fan 230. Specifically, when the outdoor fan 230 is operated, the refrigerant is radiated to the outdoor air and condensed in the outdoor heat exchanger 222 for subcooling. The subcooled refrigerant condensed in the subcooled outdoor heat exchanger 222 is lowered by gravity, passes through the subcooled expansion valve 223 set in the deployed state, and passes to the first flow path 211 of the subcooled heat exchanger 210. Inflow. In the first flow passage 211 of the subcooling heat exchanger 210, the supercooling refrigerant absorbs heat from the refrigerant of the second flow passage 212 and evaporates. The supercooling refrigerant evaporated in the subcooling heat exchanger 210 passes through the bypass pipe 224, returns to the subcooling outdoor heat exchanger 222, and heat-exchanges with the outdoor air to condense again.

At the start of the subcooling unit 200, the controller 240 of the present modification first starts the outdoor fan 230 and determines whether to start the subcooling compressor 221 while the outdoor fan 230 is operated. To judge. That is, when it is determined that the cooling of the refrigerant flowing in the refrigerant passage 205 is required, the controller 240 starts only the outdoor fan 230 while stopping the subcooling compressor 221. When the outdoor fan 230 is activated, the subcooling refrigerant is naturally circulated in the refrigerant passage 205, and the refrigerant in the second flow path 212 is cooled by the subcooling refrigerant in the subcooling heat exchanger 210. The controller 240 continues the state in which only this outdoor fan 230 is operated for a predetermined time (for example, 5 minutes), and then determines whether the cooling of the refrigerant flowing in the refrigerant passage 205 is insufficient. do. If the cooling of the refrigerant flowing in the refrigerant passage 205 is insufficient, the controller 240 starts the subcooling compressor 221.

When the subcooling compressor 221 is started, a refrigeration cycle is performed in the subcooling refrigerant circuit 220. On the other hand, if the cooling of the refrigerant is not insufficient, the controller 240 continues to operate only the outdoor fan 230 while stopping the subcooling compressor 221.

In this modification, the supercooling compressor 221 is started only when the cooling of the heat source side refrigerant is insufficient only by naturally circulating the supercooling refrigerant by the operation of the outdoor fan 230. This makes it possible to avoid the situation in which the subcooling compressor 221 is started even though the subcooling compressor 221 is not required, and the start frequency of the subcooling compressor 221 can be reduced. As a result, the time during which the subcooling compressor 221 is operated in an unstable transient state can be shortened, and the reliability of the subcooling compressor 221 can be improved.

-Eleventh embodiment Variant -

In the subcooling unit 200 of the present embodiment, a cold water circuit through which cold water flows may be configured as a cooling fluid circuit instead of the subcooling refrigerant circuit 220. In this cold water circuit, relatively low temperature water of about 5 ° C flows, for example. In the supercooling heat exchanger 210 of the present modification, a cold water circuit is connected to the first flow passage 211, and the cold water flowing in the first flow passage 211 exchanges heat with a refrigerant flowing in the second flow passage 212. do.

Here, the above embodiments are essentially preferred examples and are not intended to limit the present invention, the application thereof, or the scope of use thereof.

As described above, the present invention is useful for a subcooling device for cooling a refrigerant supplied from a heat source unit of a refrigerating device to a use unit.

Claims (26)

delete delete delete It is installed in the refrigerating device 10 for circulating the heat source side refrigerant between the heat source unit 11 and the use unit 12, 13, 14 connected by the communication pipe to perform the freezing circulation, from the heat source unit 11 A supercooling device for cooling a heat source side refrigerant of the refrigerating device 10 sent to (12, 13, 14), A refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10, A cooling fluid circuit 220 through which the cooling fluid flows, A subcooling heat exchanger 210 for cooling the heat source-side refrigerant in the refrigerant passage 205 by exchanging heat with the cooling fluid; And control means 240 for controlling the circulation state of the cooling fluid in the cooling fluid circuit 220 according to the circulation state of the heat source-side refrigerant in the refrigerant passage 205, The cooling fluid circuit is composed of a subcooling refrigerant circuit 220, The subcooling refrigerant circuit 220 includes a subcooling compressor 221 and circulates a subcooling refrigerant as a cooling fluid to perform a freezing circulation. The control means 240 is configured to control the circulating state of the subcooling refrigerant in the subcooling refrigerant circuit 220 by controlling the operation of the subcooling compressor 221, Further, the control means 240 determines the heat source side refrigerant flow direction in the refrigerant passage 205 and the presence or absence of heat source side refrigerant flow in the refrigerant passage 205 during the operation of the subcooling compressor 221. When the heat source-side refrigerant flows from the heat source unit 11 toward the use unit 12, 13, 14 in the refrigerant passage 205, the operation of the subcooling compressor 221 is detected. The heat source side refrigerant flows in the refrigerant passage 205 toward the heat source unit 11 from the use units 12, 13, and 14, and the heat source side refrigerant does not flow in the refrigerant passage 205. Subcooling apparatus, characterized in that configured to stop the subcooling compressor (221). The method according to claim 4, The control means (240) is configured to start the subcooling compressor (221) when a predetermined time elapses from the time when the subcooling compressor (221) is stopped. The method according to claim 4 or 5, In the refrigerant passage 205, a refrigerant temperature detecting means 236 for detecting the heat source side refrigerant temperature of the portion of the use unit 12, 13, 14, rather than the subcooling heat exchanger 210, The control means 240 is configured to determine the circulation state of the heat source side refrigerant based on a change in the detection value of the refrigerant temperature detection means 236 from the time when the subcooling compressor 221 is started. Supercooling device. The method according to claim 4 or 5, Refrigerant temperature detection means 236 for detecting the heat source side refrigerant temperature of the portion of the refrigerant passage 205 toward the use unit (12, 13, 14) than the subcooling heat exchanger (210); Evaporation temperature detection means 234 for detecting the evaporation temperature of the supercooling refrigerant in the subcooling heat exchanger 210, The control means 240 is configured to determine the circulation state of the heat source side refrigerant based on the detection value of the refrigerant temperature detection means 236 and the detection value of the evaporation temperature detection means 234. Device. The method according to claim 4 or 5, First refrigerant temperature detection means (237) for detecting a refrigerant temperature of the heat source side of the portion of the refrigerant passage (205) toward the use unit (12, 13, 14) rather than the subcooling heat exchanger (210); In the refrigerant passage 205, the second refrigerant temperature detecting means 238 for detecting the heat source side refrigerant temperature of the portion of the heat source unit 11 side than the subcooling heat exchanger 210, The control means 240 is configured to determine the circulation state of the heat source side refrigerant based on the detection value of the first refrigerant temperature detection means 237 and the detection value of the second refrigerant temperature detection means 238. Supercooling device characterized in that. It is installed in the refrigerating device 10 for circulating the heat source side refrigerant between the heat source unit 11 and the use unit 12, 13, 14 connected by the communication pipe to perform the freezing circulation, from the heat source unit 11 A supercooling device for cooling a heat source side refrigerant of the refrigerating device 10 sent to (12, 13, 14), A refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10, A cooling fluid circuit 220 through which the cooling fluid flows, A subcooling heat exchanger 210 for cooling the heat source-side refrigerant in the refrigerant passage 205 by exchanging heat with the cooling fluid; And control means 240 for controlling the circulation state of the cooling fluid in the cooling fluid circuit 220 according to the circulation state of the heat source-side refrigerant in the refrigerant passage 205, The refrigerant passage 205 is provided with a flow meter 251 for detecting the flow rate of the heat source side refrigerant, The control means 240 uses the detected value of the flow meter 251 as a flow state display value indicating a flow state of the heat source side refrigerant, and in the state where the cooling fluid flows in the cooling fluid circuit 220. And determining whether to continue or stop the flow of the cooling fluid on the basis of the flow state indication value. It is installed in the refrigerating device 10 for circulating the heat source side refrigerant between the heat source unit 11 and the use unit 12, 13, 14 connected by the communication pipe to perform the freezing circulation, from the heat source unit 11 A supercooling device for cooling a heat source side refrigerant of the refrigerating device 10 sent to (12, 13, 14), A refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10, A cooling fluid circuit 220 through which the cooling fluid flows, A subcooling heat exchanger 210 for cooling the heat source-side refrigerant in the refrigerant passage 205 by exchanging heat with the cooling fluid; Control means 240 for controlling the circulation state of the cooling fluid in the cooling fluid circuit 220 according to the circulation state of the heat source-side refrigerant in the refrigerant passage 205; First refrigerant temperature detection means (237) for detecting a refrigerant temperature of the heat source side of the portion of the refrigerant passage (205) toward the use unit (12, 13, 14) rather than the subcooling heat exchanger (210); In the refrigerant passage 205, the second refrigerant temperature detecting means 238 for detecting the heat source side refrigerant temperature of the portion of the heat source unit 11 side than the subcooling heat exchanger 210, The control means 240 determines the difference between the detected value of the first refrigerant temperature detecting means 237 and the detected value of the second refrigerant temperature detecting means 238 and indicates a distribution state indicating value of the heat source-side refrigerant. And in the state in which the cooling fluid flows in the cooling fluid circuit 220, determining whether to continue or stop the distribution of the cooling fluid on the basis of the distribution state display value. Supercooling device. It is installed in the refrigerating device 10 for circulating the heat source side refrigerant between the heat source unit 11 and the use unit 12, 13, 14 connected by the communication pipe to perform the freezing circulation, from the heat source unit 11 A supercooling device for cooling a heat source side refrigerant of the refrigerating device 10 sent to (12, 13, 14), A refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10, A cooling fluid circuit 220 through which the cooling fluid flows, A subcooling heat exchanger 210 for cooling the heat source-side refrigerant in the refrigerant passage 205 by exchanging heat with the cooling fluid; Control means 240 for controlling the circulation state of the cooling fluid in the cooling fluid circuit 220 according to the circulation state of the heat source-side refrigerant in the refrigerant passage 205; In the refrigerant passage 205, a refrigerant temperature detecting means 236 for detecting the heat source side refrigerant temperature of the portion of the use unit 12, 13, 14, rather than the subcooling heat exchanger 210, The control means 240 uses the change of the detected value of the coolant temperature detecting means 236 as a flow state display value indicating a flow state of the heat source side refrigerant, so that the cooling fluid is cooled in the cooling fluid circuit 220. A supercooling device, configured to determine whether to continue or stop the distribution of the cooling fluid in the distribution state based on the distribution state display value. It is installed in the refrigerating device 10 for circulating the heat source side refrigerant between the heat source unit 11 and the use unit 12, 13, 14 connected by the communication pipe to perform the freezing circulation, from the heat source unit 11 A supercooling device for cooling a heat source side refrigerant of the refrigerating device 10 sent to (12, 13, 14), A refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10, A cooling fluid circuit 220 through which the cooling fluid flows, A subcooling heat exchanger 210 for cooling the heat source-side refrigerant in the refrigerant passage 205 by exchanging heat with the cooling fluid; And control means 240 for controlling the circulation state of the cooling fluid in the cooling fluid circuit 220 according to the circulation state of the heat source-side refrigerant in the refrigerant passage 205, The cooling fluid circuit 220 includes an inlet fluid temperature detecting means 252 for detecting a cooling fluid temperature at the inlet of the subcooling heat exchanger 210 and a cooling fluid at the outlet of the subcooling heat exchanger 210. While the outlet side fluid temperature detecting means 253 for detecting the temperature is configured, The control means 240 determines a difference between the detected value of the inlet fluid temperature detecting means 252 and the detected value of the outlet fluid temperature detecting means 253 and indicates a distribution state indicating a circulation state of the heat source side refrigerant. And in the state in which the cooling fluid flows in the cooling fluid circuit 220, determining whether to continue or stop the distribution of the cooling fluid on the basis of the distribution state display value. Supercooling device. It is installed in the refrigerating device 10 for circulating the heat source side refrigerant between the heat source unit 11 and the use unit 12, 13, 14 connected by the communication pipe to perform the freezing circulation, from the heat source unit 11 A supercooling device for cooling a heat source side refrigerant of the refrigerating device 10 sent to (12, 13, 14), A refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10, A cooling fluid circuit 220 through which the cooling fluid flows, A subcooling heat exchanger 210 for cooling the heat source-side refrigerant in the refrigerant passage 205 by exchanging heat with the cooling fluid; And control means 240 for controlling the circulation state of the cooling fluid in the cooling fluid circuit 220 according to the circulation state of the heat source-side refrigerant in the refrigerant passage 205, The cooling fluid circuit is composed of a subcooling refrigerant circuit 220, The subcooling refrigerant circuit 220 includes a subcooling compressor 221, circulates a subcooling refrigerant as a cooling fluid, and performs a freezing circulation. In the subcooling refrigerant circuit 220, evaporation pressure detecting means 234 for detecting the subcooling refrigerant evaporation pressure in the subcooling heat exchanger 210, The control means 240 uses the detected value of the evaporation pressure detecting means 234 as a flow state display value indicating a flow state of the heat source-side refrigerant, and the supercooling refrigerant is circulated in the subcooling refrigerant circuit 220. The subcooling apparatus, wherein the subcooling refrigerant is configured to determine whether to continuously or stop the circulation of the subcooling refrigerant. It is installed in the refrigerating device 10 for circulating the heat source side refrigerant between the heat source unit 11 and the use unit 12, 13, 14 connected by the communication pipe to perform the freezing circulation, from the heat source unit 11 A supercooling device for cooling a heat source side refrigerant of the refrigerating device 10 sent to (12, 13, 14), A refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10, A cooling fluid circuit 220 through which the cooling fluid flows, A subcooling heat exchanger 210 for cooling the heat source-side refrigerant in the refrigerant passage 205 by exchanging heat with the cooling fluid; And control means 240 for controlling the circulation state of the cooling fluid in the cooling fluid circuit 220 according to the circulation state of the heat source-side refrigerant in the refrigerant passage 205, The cooling fluid circuit is composed of a subcooling refrigerant circuit 220, The subcooling refrigerant circuit 220 includes a subcooling compressor 221 and circulates a subcooling refrigerant as a cooling fluid to perform a freezing circulation. Refrigerant temperature detection means 236 for detecting the heat source side refrigerant temperature of the portion of the refrigerant passage 205 toward the use unit (12, 13, 14) than the subcooling heat exchanger (210); Further provided with evaporation temperature detection means 234 for detecting the evaporation temperature of the subcooling refrigerant in the subcooling heat exchanger (210), The control means 240 uses the difference between the detection value of the refrigerant temperature detection means 236 and the detection value of the evaporation temperature detection means 234 as a distribution state display value indicating a circulation state of the heat source side refrigerant. And in the state in which the subcooling refrigerant is circulated in the subcooling refrigerant circuit (220), determining whether to continue or stop the circulation of the subcooling refrigerant based on the distribution state display value. It is installed in the refrigerating device 10 for circulating the heat source side refrigerant between the heat source unit 11 and the use unit 12, 13, 14 connected by the communication pipe to perform the freezing circulation, from the heat source unit 11 A supercooling device for cooling a heat source side refrigerant of the refrigerating device 10 sent to (12, 13, 14), A refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10, A cooling fluid circuit 220 through which the cooling fluid flows, A subcooling heat exchanger 210 for cooling the heat source-side refrigerant in the refrigerant passage 205 by exchanging heat with the cooling fluid; Control means 240 for controlling the circulation state of the cooling fluid in the cooling fluid circuit 220 according to the circulation state of the heat source-side refrigerant in the refrigerant passage 205; And a refrigerant temperature detecting means 236 for detecting a heat source side refrigerant temperature of the portion of the use unit 12, 13, 14, rather than the subcooling heat exchanger 210 of the refrigerant passage 205, The control means 240 uses the detected value of the coolant temperature detecting means 236 as a flow state display value indicating a flow state of the heat source-side refrigerant, and distributes the cooling fluid in the cooling fluid circuit 220. And in the stopped state, configured to determine whether to start or stop the flow of the cooling fluid on the basis of the flow state displayed value. It is installed in the refrigerating device 10 for circulating the heat source side refrigerant between the heat source unit 11 and the use unit 12, 13, 14 connected by the communication pipe to perform the freezing circulation, from the heat source unit 11 A supercooling device for cooling a heat source side refrigerant of the refrigerating device 10 sent to (12, 13, 14), A refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10, A cooling fluid circuit 220 through which the cooling fluid flows, A subcooling heat exchanger 210 for cooling the heat source-side refrigerant in the refrigerant passage 205 by exchanging heat with the cooling fluid; Control means 240 for controlling the circulation state of the cooling fluid in the cooling fluid circuit 220 according to the circulation state of the heat source-side refrigerant in the refrigerant passage 205; And a refrigerant temperature detecting means 236 for detecting a heat source side refrigerant temperature of the portion of the use unit 12, 13, 14, rather than the subcooling heat exchanger 210 of the refrigerant passage 205, The control means 240 uses the change of the detected value of the coolant temperature detecting means 236 as a flow state display value indicating a flow state of the heat source-side refrigerant, and the cooling fluid circuit 220 controls the cooling fluid. And in the state in which the flow is stopped, to determine whether to start or stop the flow of the cooling fluid on the basis of the flow state displayed value. It is installed in the refrigerating device 10 for circulating the heat source side refrigerant between the heat source unit 11 and the use unit 12, 13, 14 connected by the communication pipe to perform the freezing circulation, from the heat source unit 11 A supercooling device for cooling a heat source side refrigerant of the refrigerating device 10 sent to (12, 13, 14), A refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10, A cooling fluid circuit 220 through which the cooling fluid flows, A subcooling heat exchanger 210 for cooling the heat source-side refrigerant in the refrigerant passage 205 by exchanging heat with the cooling fluid; And control means 240 for controlling the circulation state of the cooling fluid in the cooling fluid circuit 220 according to the circulation state of the heat source-side refrigerant in the refrigerant passage 205, The cooling fluid circuit is composed of a subcooling refrigerant circuit 220, The subcooling refrigerant circuit 220 includes a subcooling compressor 221 and circulates a subcooling refrigerant as a cooling fluid to perform a freezing circulation. An outdoor temperature detecting means 231 for detecting a temperature of outdoor air; Further comprising a refrigerant temperature detecting means 236 for detecting the heat source side refrigerant temperature of the portion of the use unit (12, 13, 14) side than the subcooling heat exchanger 210 of the refrigerant passage 205, The control means 240 uses the difference between the detection value of the refrigerant temperature detection means 236 and the detection value of the outdoor temperature detection means 231 as a distribution state display value indicating a circulation state of the heat source side refrigerant. The subcooling refrigerant circuit 220 is configured to determine whether the distribution of the subcooling refrigerant is to start or stop the distribution of the subcooling refrigerant on the basis of the distribution state display value. Supercooling device. It is installed in the refrigerating device 10 for circulating the heat source side refrigerant between the heat source unit 11 and the use unit 12, 13, 14 connected by the communication pipe to perform the freezing circulation, from the heat source unit 11 A supercooling device for cooling a heat source side refrigerant of the refrigerating device 10 sent to (12, 13, 14), While the heat source unit 11 of the refrigerating device 10 is configured to exchange heat source-side refrigerant with outdoor air, A refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10, A cooling fluid circuit 220 through which the cooling fluid flows, A subcooling heat exchanger 210 for cooling the heat source-side refrigerant in the refrigerant passage 205 by exchanging heat with the cooling fluid; An outdoor temperature detecting means 231 for detecting a temperature of outdoor air; And a control means (240) for controlling the flow state of the cooling fluid in the cooling fluid circuit (220) according to the detected value of the outdoor temperature detection means (231). The method according to claim 18, The cooling fluid circuit is composed of a subcooling refrigerant circuit 220, The subcooling refrigerant circuit (220) includes a subcooling compressor (221) and circulates the subcooling refrigerant as a cooling fluid to perform a refrigerating cycle. The method according to claim 18 or 19, The control means 240 controls the detection value of the outdoor temperature detection means 231 to continue or stop the flow of the cooling fluid while the cooling fluid flows in the cooling fluid circuit 220. And a supercooling device, configured to determine on the basis of the determination. The method according to claim 18 or 19, The control means 240, the flow of the cooling fluid in the cooling fluid circuit 220 is stopped, the flow of the cooling fluid to start or continue to stop the flow of the cooling fluid of the outdoor temperature detection means 231 And to determine based on the detected value. The method according to claim 19, A heat dissipation heat exchanger 222 connected to the subcooling refrigerant circuit 220 to heat-exchange the subcooling refrigerant with outdoor air; Is provided with an outdoor fan 230 for supplying outdoor air to the heat exchanger for heat dissipation, 222, The subcooling refrigerant circuit 220 is configured to enable a natural circulation operation to naturally circulate the subcooling refrigerant by operating the outdoor fan 230 while the subcooling compressor 221 is stopped. The control means 240, when starting the circulation of the subcooled refrigerant to start the outdoor fan 230, and causes the subcooled refrigerant circuit 220 to perform a natural circulation operation, the refrigerant passage during this natural circulation operation ( And 205) determining whether to start or continue stopping the subcooling compressor 221 according to the circulation state of the heat source-side refrigerant. It is installed in the refrigerating device 10 for circulating the heat source side refrigerant between the heat source unit 11 and the use unit 12, 13, 14 connected by the communication pipe to perform the freezing circulation, from the heat source unit 11 A supercooling device for cooling a heat source side refrigerant of the refrigerating device 10 sent to (12, 13, 14), A refrigerant passage 205 connected to the liquid side communication pipes 21 and 22 of the refrigerating device 10, A cooling fluid circuit 220 through which the cooling fluid flows, A subcooling heat exchanger 210 for cooling the heat source-side refrigerant in the refrigerant passage 205 by exchanging heat with the cooling fluid; And control means 240 for controlling the circulation state of the cooling fluid in the cooling fluid circuit 220 according to the circulation state of the heat source-side refrigerant in the refrigerant passage 205, The cooling fluid circuit is composed of a subcooling refrigerant circuit 220, The subcooling refrigerant circuit 220 includes a subcooling compressor 221 and circulates a subcooling refrigerant as a cooling fluid to perform a freezing circulation. A heat dissipation heat exchanger 222 connected to the subcooling refrigerant circuit 220 to heat-exchange the subcooling refrigerant with outdoor air; Further provided with an outdoor fan 230 for supplying outdoor air to the heat dissipation heat exchanger 222, The subcooling refrigerant circuit 220 is configured to enable a natural circulation operation to naturally circulate the subcooling refrigerant by operating the outdoor fan 230 while the subcooling compressor 221 is stopped. The control means 240, when starting the circulation of the subcooled refrigerant to start the outdoor fan 230, and causes the subcooled refrigerant circuit 220 to perform a natural circulation operation, the refrigerant passage during this natural circulation operation ( And 205) determining whether to start or continue stopping the subcooling compressor 221 according to the circulation state of the heat source-side refrigerant. The method according to any one of claims 9, 10, 11, 12, 15, or 16, The cooling fluid circuit is composed of a subcooling refrigerant circuit 220, The subcooling refrigerant circuit (220) includes a subcooling compressor (221), and performs a refrigeration cycle by circulating a subcooling refrigerant as a cooling fluid. The method of claim 24, The control means (240), by controlling the operation of the subcooling compressor (221), the subcooling device, characterized in that configured to control the circulation state of the subcooling refrigerant in the subcooling refrigerant circuit (220). The method according to any one of claims 13, 14, or 17, The control means (240), by controlling the operation of the subcooling compressor (221), the subcooling device, characterized in that configured to control the circulation state of the subcooling refrigerant in the subcooling refrigerant circuit (220).

Images