JP2005214442A - Refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerator capable of effectively maintaining a function of an intermediate pressure refrigerant bypass circuit for bypassing intermediate pressure gas refrigerant in an intermediate receiver into an intermediate pressure part in a compression stroke of a compressor. <P>SOLUTION: This refrigerator is provided with the compressor, a high pressure gas cooler for cooling high pressure side gas refrigerant, a first throttle device, the intermediate receiver for adjusting amount of refrigerant in refrigerating cycle, a second throttle device, an evaporator using outside air as heat source, and a refrigerating cycle device forming a closed circuit by connecting air-liquid separators sequentially in series. The refrigerating cycle device is provided with the intermediate pressure refrigerant bypass circuit for bypassing intermediate pressure gas refrigerant in the intermediate receiver into the intermediate pressure part in the compression stroke of the compressor. The intermediate pressure refrigerant bypass circuit is provided with a check valve for preventing refrigerant from flowing into the intermediate reciever from the compressor and a refrigerant temperature sensor for detecting refrigerant temperature on an intermediate receiver side of the check valve. Opening of the valve on at least one side of the first throttle device and the second throttle device is controlled in such a way that gas refrigerant temperature detected by the refrigerant temperature sensor becomes higher than ambient air temperature detected by an air temperature sensor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a refrigeration apparatus, and more particularly to a means for effectively maintaining the action of so-called gas injection for bypassing a medium-pressure gas refrigerant during a compression process of a compressor.

  In recent years, natural refrigerants that are refrigerated in a supercritical refrigeration cycle, such as carbon dioxide, have attracted attention in order to meet the problem of ozone depletion and the need for high temperature hot water supply in hot water supply devices. Moreover, what is described in patent document 1 is known as a freezing apparatus which performs such supercritical cycle freezing operation. In addition, when the compression ratio is increased as in such a supercritical refrigeration cycle, there are problems such as a decrease in compression efficiency and an increase in discharge gas refrigerant temperature, and therefore a two-stage compression method is used.

As an example of such a refrigeration apparatus, there is one as shown in FIG. 1 and FIG. That is, the refrigeration apparatus of FIG. 1 is a series of a high-stage compressor, a high-pressure gas cooler, a first throttle valve, an intermediate receiver, a second throttle valve, an evaporator, a low-stage compressor, and a high-stage compressor. The refrigeration cycle apparatus connected to the refrigeration cycle and configured as a closed circuit is configured to operate in a supercritical refrigeration cycle. Also, the gas part of the intermediate receiver is connected to the cylinder of the high-stage compressor, the intermediate-pressure gas refrigerant is mixed with the discharge gas of the low-stage compressor, and sucked into the high-stage compressor, and the coefficient of performance of the refrigeration cycle We are trying to improve.
The refrigeration apparatus shown in FIG. 2 of the same document includes a first stage compressor having a gas injection port, a high pressure gas cooler, a first throttle valve, an intermediate receiver, a second throttle valve, an evaporator, and the first stage compressor. A refrigeration cycle apparatus that is sequentially connected in series to form a closed circuit is configured to operate in a supercritical refrigeration cycle. Further, the gas part of the intermediate receiver is connected to the gas injection port of the compressor, and the intermediate pressure gas refrigerant is sucked in the middle of the compression process of the compressor to improve the coefficient of performance of the refrigeration cycle.

J.C.Goosmann and F.R.Zumbro, “Recent Improvements in CO2 Equipment”, published by The American Society of Refrigerating Engineers, “REFRIGERATING EBGINEERING”, July 1928, Vol. 16, No. 1, p.

  In general, in such a refrigeration apparatus, depending on the pressure of the intermediate receiver, the gas refrigerant may not flow from the gas portion of the intermediate receiver during the compression process of the compressor. However, in the prior art described above, no measures are taken for such a problem.

  The present invention has been made to solve the above-described problems of the prior art, and is an intermediate pressure refrigerant bypass circuit that bypasses the intermediate pressure gas refrigerant in the intermediate receiver to the intermediate pressure portion of the compression process of the compressor. An object of the present invention is to provide a refrigeration apparatus capable of effectively maintaining the function.

  The present invention solves the above-mentioned problem, and a refrigeration apparatus according to a first problem-solving means includes a compressor, a high-pressure gas cooler that cools a high-pressure side gas refrigerant, a first expansion device, and a refrigerant in a refrigeration cycle. An intermediate receiver for adjusting the amount, a second expansion device, an evaporator using outside air as a heat source, and a refrigeration cycle device in which a gas-liquid separator is sequentially connected in series to form a closed circuit. The intermediate pressure refrigerant bypass circuit for bypassing the intermediate pressure gas refrigerant in the intermediate receiver to the intermediate pressure portion of the compression process of the compressor is provided, and the refrigerant flow from the compressor to the intermediate receiver is supplied to the intermediate pressure refrigerant bypass circuit. A check valve for blocking, a refrigerant temperature sensor for detecting the refrigerant temperature between the check valve and the intermediate receiver, and an air temperature sensor for detecting the ambient air temperature of the intermediate pressure refrigerant bypass circuit are provided. Further, the opening degree of at least one of the first throttle device and the second throttle device is controlled so that the gas refrigerant temperature detected by the refrigerant temperature sensor is higher than the ambient air temperature detected by the air temperature sensor. It is characterized by that.

  Further, the refrigeration apparatus according to the second problem solving means does not detect the ambient air temperature of the intermediate pressure refrigerant bypass circuit with the air temperature sensor as in the first problem solving means, but instead surrounds the intermediate pressure refrigerant bypass circuit. The air temperature is a predicted value. That is, the refrigeration apparatus according to the second problem solving means includes a compressor, a high-pressure gas cooler that cools the high-pressure side gas refrigerant, a first throttle device, an intermediate receiver that adjusts the amount of refrigerant in the refrigeration cycle, and a second throttle device. A refrigerating cycle device in which an evaporator using outside air as a heat source and a gas-liquid separator are sequentially connected in series to form a closed circuit, and the refrigerating cycle device compresses the intermediate-pressure gas refrigerant in the intermediate receiver An intermediate pressure refrigerant bypass circuit that bypasses the intermediate pressure portion of the compressor compression process, the intermediate pressure refrigerant bypass circuit includes a check valve that blocks refrigerant flow from the compressor to the intermediate receiver, and the check valve And a refrigerant temperature sensor for detecting a refrigerant temperature between the intermediate receiver and the intermediate pressure refrigerant bypass circuit where a gas refrigerant temperature detected by the refrigerant temperature sensor is predicted. Characterized by comprising controlling at least one of the valve opening degree of the first throttle device and the second throttling device so that the temperature higher than the temperature.

  The refrigeration apparatus according to the third problem solving means includes a compressor, a high-pressure gas cooler that cools the high-pressure side gas refrigerant, a first throttle device, an intermediate receiver that adjusts the amount of refrigerant in the refrigeration cycle, and a second throttle device. A refrigerating cycle device in which an evaporator using outside air as a heat source and a gas-liquid separator are sequentially connected in series to form a closed circuit, and the refrigerating cycle device compresses the intermediate-pressure gas refrigerant in the intermediate receiver An intermediate pressure refrigerant bypass circuit that bypasses the intermediate pressure portion of the compressor compression process, a refrigerant temperature sensor that detects an inlet side refrigerant temperature in the intermediate pressure refrigerant bypass circuit, and a refrigerant temperature sensor that detects an outlet side refrigerant temperature, In addition, an air temperature sensor for detecting the ambient air temperature of the intermediate pressure refrigerant bypass circuit is provided, and the cooling detected by the inlet side refrigerant temperature sensor of the intermediate pressure refrigerant bypass circuit is provided. The first throttling device and the first throttle device and the first throttle device so that the temperature is higher than the air temperature detected by the air temperature sensor and the refrigerant temperature detected by the inlet side refrigerant temperature sensor is higher than the refrigerant temperature detected by the outlet side refrigerant temperature sensor. The two-throttle device is configured to control at least one valve opening degree.

  Further, the refrigeration apparatus according to the fourth problem solving means does not detect the ambient air temperature of the intermediate pressure refrigerant bypass circuit with the air temperature sensor as in the third problem solving means, but the surroundings of the intermediate pressure refrigerant bypass circuit. The air temperature is a predicted value. That is, the refrigeration apparatus according to the fourth problem solving means includes a compressor, a high-pressure gas cooler that cools the high-pressure side gas refrigerant, a first throttle device, an intermediate receiver that adjusts the amount of refrigerant in the refrigeration cycle, and a second throttle device. A refrigerating cycle device in which an evaporator using outside air as a heat source and a gas-liquid separator are sequentially connected in series to form a closed circuit, and the refrigerating cycle device compresses the intermediate-pressure gas refrigerant in the intermediate receiver An intermediate pressure refrigerant bypass circuit that bypasses the intermediate pressure portion of the compressor compression process, a refrigerant temperature sensor that detects an inlet side refrigerant temperature in the intermediate pressure refrigerant bypass circuit, and a refrigerant temperature sensor that detects an outlet side refrigerant temperature Provided, the refrigerant temperature detected by the inlet side refrigerant temperature sensor is higher than the ambient air temperature of the intermediate pressure refrigerant bypass circuit, and the inlet side refrigerant temperature is It is configured to control the valve opening degree of at least one of the first throttle device and the second throttle device so that the refrigerant temperature detected by the sensor is higher than the refrigerant temperature detected by the outlet side refrigerant temperature sensor. Features.

  The refrigeration apparatus according to the fifth problem solving means includes a compressor, a high-pressure gas cooler that cools the high-pressure side gas refrigerant, a first throttle device, an intermediate receiver that adjusts the amount of refrigerant in the refrigeration cycle, and a second throttle device. A refrigerating cycle device in which an evaporator using outside air as a heat source and a gas-liquid separator are sequentially connected in series to form a closed circuit, and the refrigerating cycle device compresses the intermediate-pressure gas refrigerant in the intermediate receiver An intermediate pressure refrigerant bypass circuit that bypasses the intermediate pressure portion of the compressor compression process is provided, and a pressure sensor that detects refrigerant pressure on the inlet side and the outlet side in the intermediate pressure refrigerant bypass circuit is provided, and the inlet side pressure sensor detects The valve opening degree of at least one of the first throttle device and the second throttle device is controlled so that the inlet side refrigerant pressure is higher than the outlet side refrigerant pressure detected by the outlet side pressure sensor. Characterized in that it is configured urchin.

  In the refrigeration cycle apparatus according to the first and second problem solving means, the refrigeration cycle apparatus may be filled with carbon dioxide as a refrigerant and operated in a supercritical cycle.

  In the refrigeration apparatus according to the first and second problem solving means, the refrigeration cycle apparatus may be a hot water supply apparatus configured to heat hot water supply using a high-pressure gas cooler.

  The refrigeration apparatus according to the first problem solving means includes an intermediate pressure refrigerant bypass circuit that bypasses the intermediate pressure gas refrigerant in the intermediate receiver to the intermediate pressure portion of the compression process of the compressor, and the intermediate pressure refrigerant bypass circuit includes the intermediate pressure refrigerant bypass circuit. The first throttle device and the second throttle device are provided so that the temperature of the gas refrigerant upstream of the check valve in the intermediate pressure refrigerant bypass circuit is higher than the ambient air temperature detected by the air temperature sensor. Therefore, it is possible to maintain the intermediate-pressure gas refrigerant flowing through the intermediate-pressure refrigerant bypass circuit. When no refrigerant is circulating in the intermediate pressure refrigerant bypass circuit, the refrigerant temperature detected by the inlet side refrigerant temperature sensor and the ambient air temperature are the same. Further, it is possible to maintain the bypass of the intermediate pressure gas refrigerant from the intermediate receiver to the compressor in the intermediate pressure refrigerant bypass circuit, and to prevent the reverse flow of the refrigerant in the intermediate pressure refrigerant bypass circuit.

  In the refrigeration apparatus according to the second problem solving means, the ambient air temperature of the intermediate pressure refrigerant bypass circuit is set as a predicted value, not a detection value by an air temperature sensor as in the first problem solving means. Therefore, while simplifying the apparatus by eliminating the need for an air temperature sensor, the bypass of the intermediate pressure gas refrigerant from the intermediate receiver to the compressor in the intermediate pressure refrigerant bypass circuit is maintained, and the refrigerant in the intermediate pressure refrigerant bypass circuit Can be prevented.

  In the refrigeration apparatus according to the third problem solving means, the refrigerant temperature detected by the inlet side refrigerant temperature sensor is higher than the air temperature detected by the air temperature sensor detecting the ambient air temperature of the intermediate pressure refrigerant bypass circuit. And the opening degree of at least one of the first throttle device and the second throttle device is controlled so that the refrigerant temperature detected by the inlet side refrigerant temperature sensor is higher than the refrigerant temperature detected by the outlet side refrigerant temperature sensor. The bypass of the intermediate pressure gas refrigerant from the intermediate receiver to the compressor in the intermediate pressure refrigerant bypass circuit can be maintained.

  In the refrigeration apparatus according to the fourth problem solving means, the ambient air temperature of the intermediate pressure refrigerant bypass circuit is set as a predicted value, not a detection value by an air temperature sensor as in the third problem solving means. Therefore, it is possible to maintain the bypass of the intermediate pressure gas refrigerant from the intermediate receiver to the compressor in the intermediate pressure refrigerant bypass circuit while simplifying the apparatus by eliminating the need for the air temperature sensor.

  Also, in each refrigeration cycle device, when operating in a supercritical cycle with carbon dioxide refrigerant filled, operation is performed in a refrigeration cycle in which the gas refrigerant temperature on the high pressure side increases while using a flammable and non-toxic safe refrigerant. be able to.

  Moreover, in the said refrigeration cycle apparatus, if it comprises so that water may be heated with a high pressure gas cooler, the hot water for high temperature using a supercritical refrigeration cycle and the hot water supply water can be supplied.

  Hereinafter, each embodiment will be described with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a refrigerant circuit diagram of the refrigeration apparatus according to the first embodiment. FIG. 2 is a Mollier diagram of a supercritical refrigeration cycle in the refrigeration apparatus. FIG. 3 is a configuration diagram around the evaporator and the gas-liquid separator of the refrigeration apparatus.

  As shown in FIG. 1, the refrigeration cycle apparatus according to Embodiment 1 is a high-pressure gas that cools a compressor 1, a high-temperature high-pressure gas refrigerant, and heats a heated fluid such as room air, warm water for heating, and hot water. The cooler 2, the first expansion device 3, the intermediate receiver 4 that adjusts the amount of refrigerant in the refrigeration cycle, the second expansion device 5, the evaporator 6 that pumps heat from the outside air, and the gas-liquid separator 7 are sequentially connected in series. A closed circuit is formed. In addition, this refrigeration apparatus is configured as an apparatus that is operated in a supercritical refrigeration cycle in which a refrigerant circuit is filled with carbon dioxide as a refrigerant.

  The compressor 1 houses a low-stage compressor section 12, a high-stage compressor section 13, an electric motor, and the like in a hermetic casing 11, and an intermediate pressure discharged from the low-stage compressor section 12 in the hermetic casing 11. The high-stage compressor section 13 is a so-called internal intermediate pressure dome type two-stage compressor formed so as to suck and discharge the intermediate pressure gas refrigerant. The two-stage compressor 1 is formed by an inverter so that the rotational speed can be varied. Further, when the outside air temperature is lowered, the heating load by the supercritical refrigeration cycle is increased, so that the two-stage compressor 1 is speeded up, and conversely, when the outside air temperature rises, the speed is slowed down. The

  The high-pressure gas cooler 2 is a heat exchanger that cools the discharge gas discharged from the high-stage compressor unit 13. Since this refrigeration cycle apparatus forms a supercritical refrigeration cycle apparatus, the high-pressure gas cooler 2 does not condense the refrigerant. The high-pressure gas cooler 2 is configured to heat warm water for heating in the case of a hot water heater, to heat indoor air in the case of a hot air heater, and to heat hot water in the case of a hot water heater.

  As the first expansion device 3 and the second expansion device 5, electric expansion valves are used, respectively. The intermediate receiver 4 adjusts the amount of refrigerant in the refrigeration cycle, and is controlled so that the pressure becomes a critical point or less by the opening control of the first expansion device 3 and the second expansion device 5. Thereby, the surplus refrigerant of the supercritical refrigeration cycle is stored in the intermediate receiver 4 as a liquid refrigerant.

The evaporator 6 is a heat exchanger that exchanges heat using outside air as a heat source, and the refrigerant itself evaporates by drawing up heat from the outside air as the low-pressure liquid refrigerant evaporates. Further, the evaporator 6 includes a refrigerant temperature sensor 61 that detects the refrigerant temperature in the middle of the evaporator 6 and a refrigerant temperature sensor 62 that detects the refrigerant temperature at the outlet of the evaporator 6. In addition, the superheat degree of the refrigerant | coolant in the evaporator 6 exit is detected by the temperature difference of the refrigerant | coolant temperature which both these refrigerant | coolant temperature sensors 61 and 62 detect. The opening degree of at least one of the first expansion device 3 and the second expansion device 5 is controlled so that the refrigerant at the outlet of the evaporator 6 is overheated.
Further, the evaporator 6 is formed such that the heat exchange pipe 65 meanders from the upper side to the lower side so that the refrigerant flows from the upper side to the lower side (see FIG. 3). 1 and 3, reference numeral 63 denotes a refrigerant inlet, and reference numeral 64 denotes a refrigerant outlet.

  Further, by connecting the gas section 41 of the intermediate receiver 4 and the inside of the closed casing 11 of the compressor 1 to the upper air supercritical refrigeration cycle, the intermediate pressure gas refrigerant in the intermediate receiver 4 is compressed in the compressor 1. An intermediate pressure refrigerant bypass circuit 8 for bypassing to the intermediate pressure portion is formed. The intermediate pressure refrigerant bypass circuit 8 is provided with a capillary tube 81 for adjusting the flow rate and a check valve 82 for blocking the refrigerant flow from the compressor 1 to the intermediate receiver 4. Further, a refrigerant temperature sensor 83 for detecting the refrigerant temperature in the intermediate pressure refrigerant bypass circuit 8 at that position is provided between the capillary tube 81 and the check valve 82 in the intermediate pressure refrigerant bypass circuit 8. Further, this refrigeration apparatus is provided with an air temperature sensor (not shown) for detecting the ambient air temperature of the intermediate pressure refrigerant bypass circuit 8. Then, the first throttling device 3 and the second throttling device are set so that the refrigerant temperature detected by the refrigerant temperature sensor 83 is higher than the ambient air temperature of the intermediate pressure refrigerant bypass circuit 8 detected by the air temperature sensor (not shown). At least one of 5 is controlled.

  Further, the supercritical refrigeration cycle is provided with a defrost circuit 9 for defrosting the evaporator 6 by bypassing the gas refrigerant in the middle of the compression process of the compressor 1 to the evaporator 6. The defrost circuit 9 is provided with an on / off valve 91 for opening and closing the defrost circuit 9. This on-off valve 91 is closed during normal operation and opened during defrosting operation.

  The gas-liquid separator 7 is an airtight container having an appropriate shape such as a cylindrical shape, and includes a refrigerant inlet 71 at a lower part of the container and a refrigerant outlet 72 at an upper part. Further, as shown in FIG. 3, the gas-liquid separator 7 is provided at a position where the refrigerant inlet 71 is higher than the refrigerant outlet 64 of the evaporator 6 by a predetermined head difference H1. In addition, the pipe 73 connecting the refrigerant inlet 71 of the gas-liquid separator 7 and the refrigerant outlet 64 of the evaporator 6, that is, the cross-sectional area of the return pipe 73 of the liquid refrigerant from the gas-liquid separator 7 to the evaporator 6, The cross-sectional area of the compressor suction pipe 14 is made larger by using a large-diameter pipe.

  The operation of the supercritical refrigeration cycle configured as described above will be described based on the Mollier diagram of FIG. The symbols for indicating each point on the Mollier diagram are correspondingly shown to indicate the state of the refrigerant at the position of each symbol on the circuit attached to the refrigerant circuit of FIG.

First, the refrigeration cycle during normal operation will be described. In this description, symbols for displaying each point on the Mollier diagram are also shown.
In the low-stage compressor section 12 of the two-stage compressor 1, the low-pressure gas refrigerant a1 on the outlet side of the gas-liquid separator 7 is sucked and compressed. The intermediate-pressure gas refrigerant b <b> 1 compressed by the low-stage compressor unit 12 is discharged into the sealed casing 11. Since the intermediate-pressure gas refrigerant g1 separated from the gas and liquid in the intermediate receiver 4 is sent into the sealed casing 11 from the gas section of the intermediate receiver 4, the discharge gas b1 of the low-stage compressor section 12 and It becomes the mixed gas refrigerant c1. The high-stage compressor section 13 sucks the mixed refrigerant c1 and becomes a high-pressure refrigerant d1 and is discharged from the two-stage compressor 1.

  The high-pressure refrigerant d1 discharged from the two-stage compressor 1 is cooled by heating the hot water for heating, the hot water supply water, or the room air with the high-pressure gas cooler 2. The cooled high-pressure gas refrigerant e1 is expanded by the first expansion device 3 and becomes a gas-liquid mixed refrigerant f1 having a pressure equal to or lower than the critical point and flows into the intermediate receiver 4. This gas-liquid mixed refrigerant f1 is gas-liquid separated in the intermediate receiver 4. The intermediate-pressure gas refrigerant g1 that has been gas-liquid separated in the intermediate receiver 4 flows into the sealed casing 11 of the two-stage compressor 1 through the intermediate-pressure refrigerant bypass circuit 8 as described above.

  On the other hand, the liquid refrigerant h <b> 1 separated by the intermediate receiver 4 is decompressed by the second expansion device 5, becomes a low-pressure gas-liquid mixed refrigerant i <b> 1, and flows into the evaporator 6. The low-pressure gas-liquid mixed refrigerant i1 that has flowed into the evaporator 6 exchanges heat with the outside air (pumps heat from the outside air), evaporates, and flows into the gas-liquid separator 7 as the low-pressure gas refrigerant j1. Further, the low-pressure gas refrigerant j1 that has flowed out of the gas-liquid separator 7, that is, the low-pressure gas refrigerant a1, is sucked into the low-stage compressor section 12 as described above.

  In such a supercritical refrigeration cycle, at least one of the first throttling device 3 and the second throttling device 5 is controlled such that the outlet refrigerant of the evaporator 6 is overheated. At this time, the degree of superheat of the refrigerant is the difference between the refrigerant temperature detected by the refrigerant temperature sensor 61 provided in the middle part of the evaporator 6 and the refrigerant temperature detected by the refrigerant temperature sensor 62 provided on the outlet side of the evaporator 6. By controlling the temperature to be constant, the refrigerant on the outlet side of the evaporator 6 is controlled to have a certain degree of superheat.

  Further, at least one of the first throttling device 3 and the second throttling device 5 is such that the temperature of the gas refrigerant upstream of the check valve 82 in the intermediate pressure refrigerant bypass circuit 8 is higher than the ambient air temperature detected by the air temperature sensor. The valve opening degree is controlled to be Thereby, in the intermediate pressure refrigerant bypass circuit 8, the bypass of the intermediate pressure gas refrigerant from the intermediate receiver 4 to the middle of the compression process of the compressor 1 is maintained.

  In the refrigeration cycle apparatus, when the evaporator 6 needs to be defrosted, the opening / closing valve 91 of the defrost circuit 9 is opened, and the opening degree of at least one of the first expansion device 3 and the second expansion device 5 is set. By adjusting, the intermediate-pressure gas refrigerant discharged from the low-stage compressor section 12 can be sent from the two-stage compressor 1 to the evaporator 6 via the defrost circuit 9. Thereby, the evaporator 6 frosted by the latent heat which an intermediate pressure gas refrigerant has can be heated and defrosted. The refrigerant discharged from the high-stage compressor unit 13 is the high-pressure gas cooler 2, the first throttling device 3, the gas unit 41 of the intermediate receiver 4, the capillary tube 81, the check valve 82, and the intermediate-pressure refrigerant bypass circuit. 8 flows into the defrost circuit 9, but the amount can be reduced by adjusting the opening degree of the first expansion device 3. Also, the liquid refrigerant in the intermediate receiver 4 can be prevented from flowing into the evaporator 6 by adjusting the opening of the second expansion device 5.

  Further, in the refrigeration cycle apparatus, when the operation is stopped for a long time in winter, the refrigerant is condensed and liquefied in the evaporator 6 and the gas-liquid separator 7 that come into contact with the outside air. Note that the refrigerant condensed and liquefied by the gas-liquid separator 7 is formed in the evaporator 6 because the refrigerant inlet 71 of the gas-liquid separator 7 is formed higher than the refrigerant outlet 64 of the evaporator 6 by a predetermined height H1. Returned. The liquid refrigerant returned from the gas-liquid separator 7 to the evaporator 6 and the liquid refrigerant liquefied by the evaporator 6 are stored in the evaporator 6. When activated in this state, liquid refrigerant flows out of the evaporator 6, but this liquid refrigerant is gas-liquid separated by the gas-liquid separator 7, so that the liquid refrigerant does not return to the compressor 1. Similarly, when the evaporator 6 is defrosted and returns to normal operation, the liquid refrigerant flows out of the evaporator 6, but is separated into gas and liquid by the gas-liquid separator 7. There is no worry about going back.

Since the cooling device according to the first embodiment is configured as described above, the following effects can be obtained.
(1) In the refrigeration apparatus according to the first embodiment, the intermediate receiver 4 that adjusts the amount of refrigerant in the refrigeration cycle apparatus is provided between the first expansion device 3 and the second expansion device 5 that are in an intermediate pressure state. Therefore, the amount of refrigerant in the refrigeration cycle apparatus can be adjusted without storing liquid refrigerant in the low-pressure side circuit. Therefore, during normal operation, the outlet of the evaporator 6 does not need to be in a moist state, and when starting up in the case where the refrigerant is sleeping due to a long-term stop, or to normal operation immediately after the defrosting operation. Except for a transition period such as when switching, it is possible to prevent the liquid refrigerant from flowing out of the evaporator 6. Further, since the excess refrigerant is stored in the intermediate receiver 4 under the intermediate pressure, the volume of the intermediate receiver 4 that stores the refrigerant can be reduced as compared with the case where the excess refrigerant is stored on the low pressure side.

  (2) In the first embodiment, excess refrigerant is supplied to the intermediate receiver 4 by controlling at least one of the first throttling device 3 and the second throttling device 5 so that the refrigerant at the outlet of the evaporator 6 is overheated. The refrigerant can be controlled while preventing the liquid from returning to the compressor 1 while storing the refrigerant.

  (3) The refrigerant temperature sensor 61 that detects the refrigerant temperature in the middle of the evaporator 6 and the refrigerant temperature sensor 62 that detects the refrigerant temperature at the evaporator outlet, and the temperatures detected by the refrigerant temperature sensors 61 and 62. Since the superheat degree at the outlet of the evaporator is detected based on the difference, it is possible to reliably detect the superheat degree of the refrigerant at the outlet of the evaporator 6 during normal operation.

  (4) Since the intermediate pressure refrigerant bypass circuit 8 for bypassing the intermediate pressure gas refrigerant in the intermediate receiver 4 to the intermediate pressure portion of the compression process of the compressor 1 is provided, the intermediate pressure gas refrigerant to be bypassed is intermediate pressure. Therefore, the compression work is reduced and the coefficient of performance of the system is improved.

(5) Further, the intermediate pressure refrigerant bypass circuit 8 for bypassing the intermediate pressure gas refrigerant in the intermediate receiver 4 to the intermediate pressure portion of the compression process of the compressor 1 is provided. The intermediate pressure refrigerant bypass circuit 8 includes a compressor. 1 is provided with a check valve 82 for blocking refrigerant flow from the intermediate receiver 4 to the intermediate receiver 4 and a refrigerant temperature sensor 83 for detecting the refrigerant temperature on the intermediate receiver side of the check valve 82. Since the valve opening degree of at least one of the first throttling device 3 and the second throttling device 5 is controlled so that the temperature of the gas refrigerant is higher than the ambient air temperature detected by an air temperature sensor (not shown). It is possible to maintain that the intermediate-pressure gas refrigerant is circulating in the pressurized refrigerant bypass circuit 8.
When the refrigerant is not circulating in the intermediate pressure refrigerant bypass circuit 8, the refrigerant temperature detected by the refrigerant temperature sensor 83 and the ambient air temperature are the same. In addition, since the check valve 82 is provided in the intermediate pressure refrigerant bypass circuit 8, the refrigerant is prevented from flowing back through the intermediate pressure refrigerant bypass circuit 8.

  (6) In this case, the compressor 1 is a so-called internal intermediate pressure dome type compressor that is configured as a two-stage compressor and discharges the discharge gas of the low-stage compressor section into the hermetic casing 11. The pressure refrigerant bypass circuit 8 can be easily formed.

  (7) In the refrigeration apparatus according to the first embodiment, the gas-liquid separator 7 is provided on the evaporator outlet side, and in particular, the liquid refrigerant separated by the gas-liquid separator 7 returns to the evaporator 6. Therefore, the liquid does not return to the compressor 1 even in a transition period such as the start of operation described above.

  (8) Further, since the gas-liquid separator 7 is provided so that the refrigerant inlet 71 of the gas-liquid separator 7 is higher than the refrigerant outlet 64 of the evaporator 6, the gas-liquid separator 7 is in operation and is not operating. The liquid refrigerant flowing into the gas-liquid separator 7 together with the gas refrigerant or the liquid refrigerant liquefied by the gas-liquid separator 7 is separated into gas and liquid and returned to the evaporator 6 by gravity. Therefore, power for returning the refrigerant from the gas-liquid separator 7 to the evaporator 6 becomes unnecessary, and the configuration is simplified. Further, since the liquid refrigerant in the gas-liquid separator 7 is always returned to the evaporator 6 without performing any operation when the operation is stopped, the liquid return to the compressor 1 in the transition period such as the start-up is surely prevented. be able to. Further, since the gas-liquid separator 7 is restarted from the state where there is no liquid refrigerant, the discharge temperature rises quickly and the rise time is shortened.

  (9) In addition, the pipe 73 connecting the refrigerant outlet 64 of the evaporator 6 and the refrigerant inlet 71 of the gas-liquid separator 7, that is, the disconnection of the liquid refrigerant return pipe 73 from the gas-liquid separator 7 to the evaporator 6 is disconnected. Since the area is larger than the cross-sectional area of the compressor suction pipe 14, the return pipe 73 can be considered as a part of the gas-liquid separator 7, and the volume of the gas-liquid separator 7 can be reduced accordingly. it can.

  (10) Further, since the volume of the intermediate receiver 4 is set to a size capable of storing surplus refrigerant in the refrigeration cycle apparatus due to changes in operating conditions, the refrigeration cycle can always be operated with the optimum refrigerant amount. The driving performance coefficient can be improved.

  (11) Since the refrigerant to be filled in the refrigeration cycle apparatus is carbon dioxide, operation in a supercritical refrigeration cycle in which the gas refrigerant temperature on the high-pressure side increases while using a flammable and non-toxic safe refrigerant. It can be carried out.

  (12) When the refrigeration cycle apparatus is configured as an apparatus that heats water such as warm water for heating and hot water using the high-pressure gas cooler 2, high-temperature hot water for heating and high-temperature hot water can be supplied. it can.

Next, Example 2 will be described with reference to FIGS. FIG. 4 is a refrigerant circuit diagram of the refrigeration apparatus according to the second embodiment. FIG. 5 is a Mollier diagram of a supercritical refrigeration cycle by the refrigeration cycle apparatus of the refrigeration apparatus.
The second embodiment shows that the compressor 1 in the first embodiment can be changed to another type, and shows another example of a means for effectively maintaining the refrigerant bypass in the intermediate pressure refrigerant bypass circuit 8. . Further, unlike the first embodiment, a heat exchanger 103 for exchanging heat between the high pressure gas refrigerant and the low pressure refrigerant is provided between the evaporator 6 and the gas-liquid separator 7.
Other configurations are the same as those of the first embodiment. In FIG. 6, the same elements as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the description thereof is omitted.

  That is, in the second embodiment, a first-stage compressor 100 having a gas injection port 102 is used instead of the two-stage compressor 1 in the first embodiment. This one-stage compressor 100 is a one-stage compression mechanism, but includes a gas injection port 102 that allows an intermediate-pressure gas refrigerant to be introduced into an intermediate pressure portion of a compression process of the compressor 100. High pressure gas refrigerant is introduced.

In the second embodiment, the intermediate pressure refrigerant bypass circuit 8 is provided between the gas portion 41 of the intermediate receiver 4 and the gas injection port 102.
As means for effectively maintaining the bypass of the refrigerant in the intermediate pressure refrigerant bypass circuit 8, the inlet side for detecting the refrigerant temperature in the intermediate pressure refrigerant bypass circuit 8 is provided on the inlet side and the outlet side of the intermediate pressure refrigerant bypass circuit 8. A refrigerant temperature sensor 104, an outlet side refrigerant temperature sensor 105, and an air temperature sensor (not shown) for detecting the ambient air temperature of the intermediate pressure refrigerant bypass circuit 8 are provided. Further, the refrigerant temperature detected by the inlet side refrigerant temperature sensor 104 is higher than the air temperature detected by the air temperature sensor, and the refrigerant temperature detected by the inlet side refrigerant temperature sensor 104 is detected by the outlet side refrigerant temperature sensor 105. The valve opening degree of at least one of the first expansion device 3 and the second expansion device 5 is controlled so as to be higher than the temperature.
The heat exchanger 103 is configured to exchange heat between the low-pressure refrigerant at the outlet of the evaporator 6 and the high-pressure gas refrigerant at the outlet of the high-pressure gas cooler 2.

  Next, Embodiment 2 configured as described above will be described based on the Mollier diagram of FIG. The symbols for indicating each point on the Mollier diagram are shown corresponding to the state of the refrigerant at the position on the circuit attached to the refrigerant circuit of FIG.

First, the refrigeration cycle during normal operation will be described. In this description, symbols for displaying each point on the Mollier diagram are also shown.
In the compressor 100, the low-pressure gas refrigerant a2 on the outlet side of the gas-liquid separator 7 is sucked and compressed. On the other hand, the intermediate-pressure gas refrigerant h <b> 2 that has been gas-liquid separated in the intermediate receiver 4 is introduced from the gas injection port 102 of the compressor 100 during the compression process in the compressor 100. Therefore, the gas refrigerant b2 compressed to the intermediate pressure by the compressor 100 is mixed with the intermediate pressure gas refrigerant h2 introduced from the gas injection port 102 to become the mixed refrigerant c2. Further, the mixed refrigerant c <b> 2 is compressed and discharged into the sealed casing 101. Further, the high-pressure gas refrigerant d2 is discharged from the sealed casing 101 into the refrigerant circuit.

  The high-pressure gas refrigerant d <b> 2 discharged from the compressor 100 is cooled by heating the hot water for hot water, hot water or indoor air with the high-pressure gas cooler 2. The high-pressure gas refrigerant e2 cooled by the high-pressure gas cooler 2 is further cooled by the heat exchanger 103. The high-pressure gas refrigerant f2 cooled by the high-pressure gas cooler 2 is expanded by the first throttling device 3 and flows into the intermediate receiver 4 as a gas-liquid mixed refrigerant g2 having a pressure below the critical point. This gas-liquid mixed refrigerant g2 is gas-liquid separated in the intermediate receiver 4. The intermediate-pressure gas refrigerant h2 that has been gas-liquid separated in the intermediate receiver 4 flows into the sealed casing 101 of the compressor 100 through the intermediate-pressure refrigerant bypass circuit 8 as described above.

  On the other hand, the liquid refrigerant i2 that has been gas-liquid separated by the intermediate receiver 4 is decompressed by the second expansion device 5 and flows into the evaporator 6 as a low-pressure gas-liquid mixed refrigerant j2. The low-pressure gas-liquid mixed refrigerant j2 that has flowed into the evaporator 6 exchanges heat with the outside air, pumps heat from the outside air, evaporates, and flows into the heat exchanger 103 as a wet low-pressure refrigerant k2. The wet low-pressure refrigerant k2 flowing into the heat exchanger 103 is heated by exchanging heat with the high-pressure gas refrigerant e2, and becomes superheated low-pressure gas refrigerant l2 and flows into the gas-liquid separator 7. Further, the low-pressure gas refrigerant 12 that has flowed into the gas-liquid separator 7, that is, the low-pressure gas refrigerant a 2, flows out of the gas-liquid separator 7 and is sucked into the compressor 100.

  In such a supercritical refrigeration cycle, at least one of the first throttling device 3 and the second throttling device 5 is controlled so that the outlet refrigerant of the evaporator 6 is overheated, as in the case of the first embodiment. . At this time, the degree of superheat of the refrigerant is the difference between the refrigerant temperature detected by the refrigerant temperature sensor 61 provided in the middle part of the evaporator 6 and the refrigerant temperature detected by the refrigerant temperature sensor 62 provided on the outlet side of the evaporator 6. By controlling the temperature to be constant, the refrigerant on the outlet side of the evaporator 6 is controlled to have a certain degree of superheat.

Further, at least one of the first throttle device 3 and the second throttle device 5 has a refrigerant temperature detected by the inlet side refrigerant temperature sensor 104 higher than the air temperature detected by the air temperature sensor, and the inlet side refrigerant temperature sensor 104. The opening degree of the valve is controlled so that the refrigerant temperature detected by the refrigerant is higher than the refrigerant temperature detected by the outlet side refrigerant temperature sensor 105. Thereby, the bypass of the intermediate pressure gas refrigerant from the intermediate receiver 4 to the compressor 100 in the intermediate pressure refrigerant bypass circuit 8 can be maintained.
When no refrigerant is circulating in the intermediate pressure refrigerant bypass circuit 8, the refrigerant in the intermediate pressure refrigerant bypass circuit 8 exchanges heat with the ambient air, and the refrigerant temperature detected by the inlet side refrigerant temperature sensor 104 and the outlet side. The refrigerant temperature detected by the refrigerant temperature sensor 105 is the same. If the refrigerant flows back from the compressor 100 to the intermediate receiver 4 in the intermediate pressure refrigerant bypass circuit 8, the refrigerant temperature detected by the inlet-side refrigerant temperature sensor 104 when the refrigerant flows in the predetermined direction described above is used. The relationship with the refrigerant temperature detected by the outlet side refrigerant temperature sensor 105 is reversed.

  In the above refrigeration cycle apparatus, when defrosting of the evaporator 6 is necessary, the opening / closing valve 91 of the defrost circuit 9 is opened, the first expansion device 3 is opened, and the opening of the second expansion device 5 is increased. By adjusting, the high-pressure gas refrigerant discharged from the compressor 100 becomes the high-pressure gas cooler 2, the first throttling device 3, the gas part 41 of the intermediate receiver 4, the capillary tube 81, the intermediate-pressure refrigerant bypass circuit 8 and the defrost circuit 9. Then, the refrigerant is sent to the evaporator 6 as an intermediate-pressure gas refrigerant. Thereby, the evaporator 6 can be heated and defrosted.

  In the refrigeration cycle apparatus, when the operation is stopped for a long time in winter or when the normal operation is performed after the defrosting operation, the liquid refrigerant flows out from the evaporator 6. Similarly, since gas-liquid separation is performed by the gas-liquid separator 7, there is no fear that the liquid refrigerant returns to the compressor 1.

  Since the cooling device according to the second embodiment is configured as described above, the effects (1) to (4) and (7) to (12) described above are achieved as in the case of the first embodiment. Can do.

  In the case of the second embodiment, the inlet side refrigerant temperature sensor 104 that detects the refrigerant temperature in the intermediate pressure refrigerant bypass circuit 8 and the outlet side refrigerant temperature sensor 105 on the inlet side and outlet side of the intermediate pressure refrigerant bypass circuit 8. And an air temperature sensor (not shown) for detecting the ambient air temperature of the intermediate pressure refrigerant bypass circuit 8 is provided. Further, the refrigerant temperature detected by the inlet side refrigerant temperature sensor 104 is higher than the air temperature detected by the air temperature sensor, and the refrigerant temperature detected by the inlet side refrigerant temperature sensor 104 is detected by the outlet side refrigerant temperature sensor 105. Since the valve opening degree of at least one of the first throttle device 3 and the second throttle device 5 is controlled to be higher than the temperature, the intermediate pressure gas from the intermediate receiver 4 to the compressor 1 by the intermediate pressure refrigerant bypass circuit 8 is controlled. Refrigerant bypass can be maintained.

Next, Example 3 will be described with reference to FIG. FIG. 6 is a refrigerant circuit diagram of the refrigeration apparatus according to the third embodiment. In FIG. 6, the same elements as those of the second embodiment are denoted by the same reference numerals as those of the second embodiment, and the description thereof is omitted.
In the third embodiment, the means for effectively maintaining the bypass of the refrigerant in the intermediate pressure refrigerant bypass circuit 8 in the second embodiment is changed to another example. That is, in the third embodiment, the pressure sensors 201 and 202 for detecting the refrigerant pressure on the inlet side and the outlet side in the intermediate pressure refrigerant bypass circuit 8 are provided, and the refrigerant pressure detected by the inlet side pressure sensor 201 is The valve opening degree of at least one of the first throttling device 3 and the second throttling device 5 is controlled so as to be higher than the detected refrigerant pressure.

  With this configuration, since the refrigerant flows from the inlet side (intermediate receiver 4 side) to the outlet side (compressor 1 side) in the intermediate pressure refrigerant bypass circuit 8, the intermediate pressure gas refrigerant flows through the intermediate pressure refrigerant bypass circuit 8. Can be maintained. When the refrigerant is not circulating in the intermediate pressure refrigerant bypass circuit 8, the refrigerant pressure detected by the inlet side pressure sensor 201 and the refrigerant pressure detected by the outlet side pressure sensor 202 are the same. When the refrigerant flows back through the intermediate pressure refrigerant bypass circuit 8, the refrigerant pressure detected by the outlet side pressure sensor 202 becomes higher than the refrigerant pressure detected by the inlet side pressure sensor 201.

(Modification)
In the first embodiment and the second embodiment described above, the ambient air temperature of the intermediate pressure refrigerant bypass circuit 8 is detected by the air temperature sensor. Instead of this, a change in the outside air temperature is predicted in advance and the outside air temperature is predicted. A predetermined temperature that is higher is determined. The refrigerant temperature detected by the inlet-side refrigerant temperature sensor 104 is such that the refrigerant temperature detected by the inlet-side refrigerant temperature sensor 104 is higher than the estimated ambient air temperature of the intermediate pressure refrigerant bypass circuit 8. You may make it control the valve opening degree of at least one of the 1st expansion device 3 and the 2nd expansion device 5 so that it may become higher than the refrigerant | coolant temperature which the temperature sensor 105 detects.

  This eliminates the need for an air temperature sensor, thus maintaining the bypass of the intermediate-pressure gas refrigerant from the intermediate receiver 4 to the compressor 1 in the intermediate-pressure refrigerant bypass circuit 8 while simplifying the apparatus, and maintaining the intermediate pressure. The reverse flow of the refrigerant in the refrigerant bypass circuit 8 can be prevented.

  The refrigeration apparatus described in detail above can be widely used for general refrigeration apparatuses. In particular, a heat pump type home air conditioner that uses outside air as a heat source, a commercial air conditioner (packaged air conditioner), a heat pump type hot water heating apparatus that uses an outside air heat source, and an outside air heat source. It is used for the heat pump type hot-water supply apparatus of No ..

It is a refrigerant circuit figure of the refrigerating device concerning Example 1 of the present invention. It is a Mollier diagram of the supercritical refrigeration cycle in the same refrigeration apparatus. It is a block diagram around the evaporator and gas-liquid separator of the freezing apparatus. It is a refrigerant circuit figure of the freezing apparatus which concerns on Example 2 of this invention. It is a Mollier diagram of the supercritical refrigeration cycle in the same refrigeration apparatus. It is a refrigerant circuit figure of the freezing apparatus which concerns on Example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 High pressure gas cooler 3 1st expansion device 4 Intermediate receiver 5 2nd expansion device 6 Evaporator 7 Gas-liquid separator 8 Intermediate pressure refrigerant bypass circuit 9 Defrost circuit 11 Sealed casing 12 Low stage compressor part 13 High Stage side compressor section 14 Compressor intake pipe 41 Gas section 61 Refrigerant temperature sensor 62 Refrigerant temperature sensor 63 Refrigerant inlet 64 Refrigerant outlet 81 Capillary tube 82 Check valve 83 Refrigerant temperature sensor 100 Compressor 102 Gas injection port 104 Inlet side refrigerant temperature Sensor 105 Outlet side refrigerant temperature sensor 201 Inlet side pressure sensor 202 Outlet side pressure sensor

Claims (7)

  A compressor, a high-pressure gas cooler that cools the high-pressure side gas refrigerant, a first throttle device, an intermediate receiver that adjusts the amount of refrigerant in the refrigeration cycle, a second throttle device, an evaporator that uses outside air as a heat source, and a gas-liquid separator. A refrigeration cycle apparatus that is sequentially connected in series to form a closed circuit, and further, the refrigeration cycle apparatus bypasses the intermediate pressure gas refrigerant in the intermediate receiver to an intermediate pressure portion of a compressor compression process. The intermediate pressure refrigerant bypass circuit is provided with a bypass circuit. The intermediate pressure refrigerant bypass circuit includes a check valve for blocking refrigerant flow from the compressor to the intermediate receiver, and a refrigerant temperature for detecting a refrigerant temperature between the check valve and the intermediate receiver. A sensor and an air temperature sensor for detecting the ambient air temperature of the intermediate pressure refrigerant bypass circuit, and the gas refrigerant temperature detected by the refrigerant temperature sensor is detected by the air temperature sensor. Refrigerating apparatus characterized by comprising controlling at least one of the valve opening degree of the first throttle device and the second throttle device so as to be higher than the ambient air temperature to.   A compressor, a high-pressure gas cooler that cools the high-pressure side gas refrigerant, a first throttle device, an intermediate receiver that adjusts the amount of refrigerant in the refrigeration cycle, a second throttle device, an evaporator that uses outside air as a heat source, and a gas-liquid separator. A refrigeration cycle apparatus that is sequentially connected in series to form a closed circuit, and further, the refrigeration cycle apparatus bypasses the intermediate pressure gas refrigerant in the intermediate receiver to an intermediate pressure portion of a compressor compression process. The intermediate pressure refrigerant bypass circuit is provided with a bypass circuit. The intermediate pressure refrigerant bypass circuit includes a check valve for blocking refrigerant flow from the compressor to the intermediate receiver, and a refrigerant temperature for detecting a refrigerant temperature between the check valve and the intermediate receiver. And a first throttling device and a second throttling device so that the gas refrigerant temperature detected by the refrigerant temperature sensor is higher than the estimated ambient air temperature of the intermediate pressure refrigerant bypass circuit. Refrigerating apparatus characterized by comprising controlling at least one of the valve opening of the device.   A compressor, a high-pressure gas cooler that cools the high-pressure side gas refrigerant, a first throttle device, an intermediate receiver that adjusts the amount of refrigerant in the refrigeration cycle, a second throttle device, an evaporator that uses outside air as a heat source, and a gas-liquid separator. A refrigeration cycle apparatus that is sequentially connected in series to form a closed circuit, and further, the refrigeration cycle apparatus bypasses the intermediate pressure gas refrigerant in the intermediate receiver to an intermediate pressure portion of a compressor compression process. A refrigerant temperature sensor for detecting an inlet side refrigerant temperature in the intermediate pressure refrigerant bypass circuit, a refrigerant temperature sensor for detecting an outlet side refrigerant temperature, and an ambient air temperature of the intermediate pressure refrigerant bypass circuit are provided. An air temperature sensor is provided, and the refrigerant temperature detected by the inlet side refrigerant temperature sensor of the intermediate pressure refrigerant bypass circuit is the air temperature detected by the air temperature sensor. At least one of the first throttle device and the second throttle device so that the refrigerant temperature detected by the inlet-side refrigerant temperature sensor is higher than the refrigerant temperature detected by the outlet-side refrigerant temperature sensor. A refrigeration apparatus configured to control the refrigeration.   A compressor, a high-pressure gas cooler that cools the high-pressure side gas refrigerant, a first throttle device, an intermediate receiver that adjusts the amount of refrigerant in the refrigeration cycle, a second throttle device, an evaporator that uses outside air as a heat source, and a gas-liquid separator. A refrigeration cycle apparatus that is sequentially connected in series to form a closed circuit, and further, the refrigeration cycle apparatus bypasses the intermediate pressure gas refrigerant in the intermediate receiver to an intermediate pressure portion of a compressor compression process. A bypass circuit is provided, and a refrigerant temperature sensor for detecting the inlet side refrigerant temperature and a refrigerant temperature sensor for detecting the outlet side refrigerant temperature in the intermediate pressure refrigerant bypass circuit are provided, and the refrigerant temperature detected by the inlet side refrigerant temperature sensor is predicted. The refrigerant temperature detected by the inlet side refrigerant temperature sensor is higher than the ambient air temperature of the intermediate pressure refrigerant bypass circuit, and the outlet side refrigerant temperature sensor To be higher than the refrigerant temperature detected by the server, the refrigeration apparatus characterized by being configured to control at least one valve opening degree of the first throttle device and the second throttling device.   A compressor, a high-pressure gas cooler that cools the high-pressure side gas refrigerant, a first throttle device, an intermediate receiver that adjusts the amount of refrigerant in the refrigeration cycle, a second throttle device, an evaporator that uses outside air as a heat source, and a gas-liquid separator. A refrigeration cycle apparatus that is sequentially connected in series to form a closed circuit, and further, the refrigeration cycle apparatus bypasses the intermediate pressure gas refrigerant in the intermediate receiver to an intermediate pressure portion of a compressor compression process. In addition to the bypass circuit, a pressure sensor for detecting the refrigerant pressure on the inlet side and the outlet side in the intermediate pressure refrigerant bypass circuit is provided, and the outlet side pressure detected by the outlet side pressure sensor is detected by the inlet side pressure sensor. A refrigeration apparatus configured to control a valve opening degree of at least one of the first throttling device and the second throttling device so as to be higher than the refrigerant pressure. .   The refrigeration apparatus according to any one of claims 1 to 5, wherein the refrigeration cycle apparatus is filled with carbon dioxide as a refrigerant and is operated in a supercritical cycle.   The refrigeration apparatus according to claim 6, wherein the refrigeration cycle apparatus is configured to heat water by a high-pressure gas cooler.

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