JPH07190455A - Refrigerating/air-conditioning system - Google Patents

Abstract

PURPOSE:To lower power consumption of a compressor without stopping the compressor, by lowering an inlet pressure of the compressor by reducing the opening of a flow control device. CONSTITUTION:According to an instruction of a demand control judging device which starts a demand control (24, 25) when a detected power W is larger than a prescribed power value WD, a demand signal part transmits a demand signal (26) to an operation control part through a transmission line. When the operation control part having the function of an opening control means changes the opening Sj of a flow control means from the current opening Sj to a prescribed opening smaller than the former by DELTASj on receiving the demand signal, an inlet pressure of a compressor lowers. When the low pressure is not lower than a prescribed value (a) (28), however, the input is judged not to have lowered sufficiently and the opening is reduced again (27). When a high pressure rises, the opening is increased so as to prevent also a rise in power consumption of the compressor. By reducing the opening of the flow control device, in this way, the power consumption can be lowered without stopping the compressor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to demand control of a refrigeration system using a refrigeration cycle.

[0002]

2. Description of the Related Art FIG. 24 shows a conventional refrigeration system. In the figure, 1 is a compressor, 2 is a four-way switching valve, 3 is a heat source side heat exchanger, 4 is a flow rate control device, 5 is an indoor side heat exchanger as a use side heat exchanger, 6 is an accumulator, and 7 is The heat source unit, 8 is an indoor unit. 1
3 and 14 are thermistors, which detect the inflow and outflow temperatures of the refrigerant in the indoor heat exchanger 5, respectively. A pressure sensor 15 detects the pressure of the refrigerant discharged from the compressor 1. In the figure, the solid line arrow indicates the flow direction of the refrigerant during the cooling operation,
The broken line arrow indicates the flow direction of the refrigerant during the heating operation. FIG. 25 is a control block diagram, and the power monitoring device 9 mainly monitors the power consumed by the heat source device 7. Reference numeral 10 is a demand control determination device, and 12 is an operation control unit that controls the compressor 1, the four-way switching valve 2, and the flow rate control device 4 to control the operation of the refrigeration cycle.

The operation during the cooling operation will be described here. The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows into the heat-source-unit-side heat exchanger 3 through the four-way switching valve 2 and radiates heat there to condense into a high-pressure liquid refrigerant. That is, the heat source unit side heat exchanger 3 is a condenser. This liquid refrigerant is a flow rate control device 4
The pressure is reduced by and flows into the indoor heat exchanger 5 as a low-pressure gas-liquid two-phase refrigerant. By absorbing heat here, most of the liquid refrigerant portion evaporates. That is, the indoor heat exchanger 5 is an evaporator. The refrigerant discharged from the indoor heat exchanger 5 flows into the accumulator 6 via the four-way switching valve 2, is separated into the liquid refrigerant and the gas refrigerant that have not evaporated in the indoor heat exchanger 5, and only the gas refrigerant flows out of the accumulator 6. Return from the pipe to the compressor 1 through the suction pipe of the compressor 1. In this way, the refrigeration cycle during cooling is formed.

At this time, the thermistor 14 is the indoor heat exchanger 5
The temperature of the gas-liquid two-phase refrigerant at the inlet is detected, and the thermistor 13 detects the temperature of the gas single phase or the refrigerant in which the liquid is slightly mixed. Since the temperature of the refrigerant in the gas-liquid two-phase state is equal to the saturation temperature of the pressure, the temperature detected by the thermistor 13 is changed to the thermistor 14
If the detected temperature is subtracted, the refrigerant superheat degree at the outlet of the indoor heat exchanger 5 is obtained. In this way, the degree of superheat of the refrigerant is obtained from the detected temperatures of the thermistor 13 and the thermistor 14, and the opening degree of the flow rate control device 4 is adjusted so as to reach a certain target value.

Next, the operation during the heating operation will be described. The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is transferred to the four-way switching valve 2
And then flows into the indoor heat exchanger 5, where it radiates heat and condenses to become a high-pressure liquid refrigerant. That is, the indoor heat exchanger is a condenser. This liquid refrigerant is decompressed by the flow rate control device 4 and is used as a low-pressure gas-liquid two-phase refrigerant in the heat exchanger 3
Flow into. By absorbing heat here, most of the liquid refrigerant portion evaporates. That is, the heat source unit side heat exchanger 3 is an evaporator. The refrigerant discharged from the heat source unit side heat exchanger 3 flows into the accumulator 6 via the four-way switching valve 2 and is separated into the non-evaporated liquid refrigerant and the gas refrigerant in the heat source unit side heat exchanger 3 and only the gas refrigerant is accumulated. From the outflow pipe to the compressor 1 via the suction pipe of the compressor 1. In this way, the refrigeration cycle during heating is formed.

The degree of condensation is determined by the degree of supercooling of the refrigerant at the outlet of the indoor heat exchanger 5, and the opening degree of the flow control device 4 is adjusted. The degree of supercooling is simply determined by the difference between the temperature detected by the thermistor 14 and the saturation temperature of the pressure detected by the pressure sensor 15.

Here, the conventional demand control will be described. Demand control sets an upper limit on the amount of power consumption, monitors the power consumption so that it does not exceed that amount, and if the power consumption exceeds the upper limit of the amount of power, stops the operation of the target device Control that suppresses capacity. In addition to this, there is also demand control that presets a time zone in which power consumption is expected to increase during the day and forcibly reduces or stops the maximum capacity of the target device during that time zone. . In the demand control, the power amount or the power consumption is usually managed by a device other than the target device.

26 and 27 show a control flow example of a case where demand control is performed in a conventional refrigeration system. 26 shows the case where the compressor 1 has a fixed capacity, and FIG. 27 shows the case where the compressor 1 has a variable capacity. First, the flow of FIG. 26 will be described. During the operation of the compressor, the power consumption W is monitored in step 101. When the power consumption W becomes larger than the demand setting power WD, demand control is started (step 202,
203). Then, the operation control unit 12 stops the compressor 1 (step 204). At this time, the timer starts counting, and the compressor 1 is stopped until a predetermined time Ts (steps 205 and 206). After that, the compressor 1 is restarted (step 207). In this way, the amount of power can be reduced by operating and stopping according to the power consumption.

Next, the case where the capacity of the compressor 1 can be controlled will be described with reference to FIG. First, in step 208, the power consumption of the heat source device 7 is detected. At this time, when the power consumption W becomes larger than the demand set power WD, demand control is started (steps 209 and 210). And the operation control unit 1
2 reduces the operating frequency of the compressor 1 by ΔF from the current F * to suppress the capacity (step 211). This operation is W ≦
Repeat until it becomes WD. In this way, power consumption is suppressed by suppressing power consumption.

[0010]

In the conventional refrigeration system, demand control is performed by repeating operation / stop in a fixed capacity compressor. In such a case, the capacity of the refrigeration system becomes zero by stopping the compressor. In addition, stopping the compressor means operating the compressor next time, and when the compressor is operated from the stop, the load on the driving part in the compressor is large and the number of times is large It may lead to abrasion of parts and shorten the life of the compressor. Even in the case of a variable capacity compressor, a plurality of compressors are provided in parallel, and even when sequentially starting or sequentially lowering according to the capacity, one of the compressors may be stopped by the demand control, so the same compressor is used. May shorten the service life of the.

When the capacity of the compressor is controllable and the capacity of the compressor is reduced by demand control, the flow rate of the refrigerant naturally decreases. At this time, if the degree of throttling in the refrigeration cycle remains the same, the throttling effect becomes relatively loose, so the low pressure rises, and eventually the suction pressure of the compressor rises. Generally, a part of the lubricating oil in the compressor is mixed with the discharged refrigerant and flows out from the compressor, but the discharged amount of this lubricating oil increases as the suction pressure of the compressor rises. If the suction pressure of the compressor rises too much, the amount of lubricating oil discharged from the compressor will exceed the amount of lubricating oil that returns to the compressor. It may be damaged due to burn-in.

[0012]

A refrigeration / air-conditioning system according to the present invention includes a refrigerant circuit formed by connecting a compressor, a heat source side heat exchanger, a flow rate control device, a utilization side heat exchanger and the like. A refrigeration / air conditioning system, a demand control unit that reduces the amount of power consumed by the refrigeration / air conditioning system, and an opening control unit that reduces the opening of the flow rate control device based on the output of the demand control unit. It is a thing.

Further, the opening degree of the flow rate control device is changed stepwise according to the degree of power reduction demand from the demand control section.

Further, the refrigeration / air-conditioning system is equipped with a refrigerant circuit which is connected to a compressor, a heat source side heat exchanger, a flow rate control device, a utilization side heat exchanger, and the like, and is consumed by the refrigeration / air-conditioning system. A demand control unit that reduces the amount of electric power, and an opening control unit that reduces at least one of the maximum opening and the minimum opening of the flow rate control device by a predetermined value based on the output of the demand control unit. Is provided.

Further, at least one of the maximum opening amount and the minimum opening amount of the flow rate control device is changed stepwise in accordance with the degree of power reduction demand from the demand control unit.

A refrigerating / air-conditioning apparatus having a refrigerant circuit formed by connecting a compressor, a heat source side heat exchanger, a flow rate control device, a utilization side heat exchanger, etc., and the above-mentioned during cooling operation or heating operation. A superheat degree detecting means for detecting a superheat degree or a supercooling degree on the refrigerant outflow side of the utilization side heat exchanger, or a supercooling degree detecting means, and the superheat degree detecting means or the supercooling degree detecting means. A degree of opening control means for comparing the degree of superheat or degree of supercooling with a preset target value, and controlling the degree of opening of the flow rate control device so that the degree of superheat or the degree of temperature cooling becomes the target value. When,
A demand control unit that reduces the amount of electric power consumed in the refrigeration / air-conditioning system, and a superheat degree based on the output of the demand control unit, or a superheat degree that makes a target value of the supercooling degree a larger predetermined value, or A supercooling degree control means is provided.

Further, at least one of the target values of the degree of superheat or the degree of subcool is changed stepwise in accordance with the degree of demand for power reduction from the demand controller.

Further, the refrigeration / air-conditioning apparatus is equipped with a refrigerant circuit which is connected with a compressor, a heat source side heat exchanger, a flow rate control device, a utilization side heat exchanger, etc., and is consumed by the refrigeration / air-conditioning apparatus. A demand control unit that reduces the amount of electric power, a capacity control unit that reduces the compressor capacity based on the output of the demand control unit, a pressure detection unit that detects the suction side pressure of the compressor, and a pressure detection unit that detects the pressure. When the applied pressure is equal to or higher than a predetermined pressure, an opening control means for reducing the opening of the flow rate control device is provided.

Further, a refrigeration / air-conditioning apparatus having a refrigerant circuit formed by connecting a compressor, a heat source side heat exchanger, a flow rate control device, a use-side heat exchanger, etc., and electric power consumed by the refrigeration / air conditioning apparatus. The demand control unit for reducing the amount, the capacity control unit for reducing the compressor capacity based on the output from the demand control unit, and the flow control device when the total operating capacity of the utilization side heat exchanger is equal to or more than a predetermined capacity. And an opening control means for reducing the opening.

[0020]

In the refrigeration / air-conditioning system configured as described above, the opening control means reduces the opening of the flow rate control device based on the output from the demand control section to lower the suction pressure of the compressor, The density of the refrigerant is reduced to reduce the circulation amount. Therefore, the work of the compressor is reduced and the power consumption of the compressor is also reduced. Therefore, if the suction pressure of the compressor is reduced, the power consumption of the compressor can be reduced without stopping the compressor. Then, the suction pressure of the compressor is reduced stepwise by controlling the opening degree of the flow rate control device stepwise according to the degree of power reduction request from the demand control unit, and the power consumption is reduced stepwise.

Further, by the output of the demand control unit, the opening control means sets at least one of the currently set maximum opening or minimum opening to a smaller predetermined set opening, When the current opening of the flow rate control device is blocked by the maximum opening in order to increase the opening for control, the opening is forcibly reduced by decreasing the maximum opening. On the contrary, if the minimum opening is attempted to be reduced in terms of control, the minimum opening can be reduced to reduce the opening. As described above, as a result, the degree of opening is reduced, so that the throttling effect is improved, and the power consumption of the compressor can be reduced without reducing the suction pressure of the compressor and stopping the compressor. Then, the power consumption can be reduced stepwise by changing at least one of the maximum opening and the minimum opening stepwise in accordance with the degree of power reduction request from the demand controller.

Further, based on the output from the demand control unit, the target value of the superheat degree or supercooling degree at the refrigerant outlet side of the utilization side heat exchanger during the cooling operation or the heating operation is set to a larger predetermined target value. As a result, the opening of the flow rate limiting device is controlled to be small via the opening control means, so that the suction pressure of the compressor is reduced and the power consumption of the compressor is reduced without stopping the compressor. You can Then, in accordance with the degree of power reduction demand from the demand control unit, at least one of the target values of the heating degree or the subcooling degree is changed stepwise, so that the opening degree control means can stepwise In addition, the suction pressure of the compressor can be reduced, and the power consumption can be reduced stepwise.

Further, when the operating capacity of the compressor is reduced by the capacity control means based on the output from the demand control section and the suction pressure of the compressor is equal to or higher than a predetermined pressure, the compressor is controlled via the opening degree control means. Reduce the suction pressure of.

When the operating capacity of the compressor is reduced by the capacity control means based on the output from the demand control section and the total operating capacity of the heat exchanger on the use side is equal to or greater than the predetermined capacity, the opening control means is operated. Through this, the opening degree of the flow rate control device is reduced to reduce the suction pressure of the compressor.

[0025]

【Example】

Example 1. FIG. 1 is a refrigerant circuit diagram in a refrigeration system according to an embodiment of the present invention. 1, 1 is a compressor, 2 is a four-way switching valve, 3 is a heat source side heat exchanger, 4 is a flow rate control device, 5 is an indoor side heat exchanger as a use side heat exchanger, 6 is an accumulator, and 7 is Heat source machine, 8 is an indoor unit,
13 is a thermistor for detecting the temperature of the refrigerant flowing from the indoor heat exchanger 5 to the four-way switching valve 2 during the cooling operation, 14 is a thermistor for detecting the refrigerant temperature between the indoor heat exchanger 5 and the flow rate control device 4, 15 Is a pressure sensor for detecting the discharge pressure of the compressor, 16 is a low pressure saturation temperature generation circuit, 17 is a thermistor for detecting low pressure saturation temperature, and 21 is an open / close valve for high pressure control. FIG. 2 is a control block diagram, 20 is a power monitoring device, 9 is a demand control determination device, and 10 is a demand control unit configured by a demand signal transmission unit 11. For example, the demand control unit is separated from a refrigeration system such as a central control room of a building. Installed in a different place, connected to the air conditioner by a transmission line, and sends a demand signal as necessary to the operation control unit 1 of the refrigeration system.
Send to 2. Reference numeral 12 is an operation control unit of the refrigeration system, which receives inputs from the thermistors 13, 14, 17 and the pressure sensor 15 and controls the compressor 1, the flow rate control device 4, the four-way switching valve 2, and the on-off valve 21.

The movement of the refrigerant in the refrigerant circuit is almost the same as that of the conventional example, but since there is a part different from the conventional example, that point will be described. One of the different parts is the low-pressure saturation temperature generation circuit 16 and the thermistor 17. Here, a method of detecting a low pressure will be described by taking a cooling operation as an example. During cooling, the heat source unit side heat exchanger 3 acts as a condenser, and the refrigerant comes out as a condensed liquid. A part of this liquid refrigerant is made to flow to the saturation temperature generation circuit 16. Saturation temperature generation circuit 16
Has a capillary tube in the middle, and the liquid refrigerant becomes a low-pressure two-phase refrigerant due to the throttling action. By detecting the temperature of this refrigerant with the thermistor 17, the low temperature saturation temperature changes, and the low pressure can be uniquely determined. This saturated temperature conversion pressure can be used instead of the suction pressure of the compressor. The pressure sensor (not shown) may be used in the suction portion of the compressor for detection, but the thermistor is advantageous because it is cheaper than the pressure sensor.

Next, the on-off valve 21 will be described. Since the on-off valve 21 is mainly used during cooling, a description will be given by taking a cooling operation as an example. During cooling, the heat source unit side heat exchanger 3 has a high pressure and its inlet side is in a gas state, and its outlet side is in a substantially liquid state. Normally, when the amount of refrigerant in the refrigerant circuit is an appropriate amount, the low pressure side of the compressor goes down as the opening degree of the flow rate control device 4 becomes smaller. The flow rate control device 4 is a so-called pressure reducing device. However, when the amount of the refrigerant is excessive, first, the refrigerant accumulated in the accumulator 6 is returned to the accumulator 6 by decreasing the opening degree of the flow controller 4, and then the refrigerant of the flow controller 4 is reduced. The liquid is accumulated in the near side, that is, inside the heat exchanger 3 on the heat source device side as a liquid state. In the case of a condenser, when the liquid portion inside becomes large, it becomes difficult to perform heat exchange, and as a result, the high pressure tends to rise. If it is left as it is, the pressure will rise excessively, causing a problem in the refrigerant circuit. An on-off valve 21 is provided to prevent this. When the opening / closing valve 21 is opened, the refrigerant accumulated as liquid is bypassed to the accumulator 6. As a result, the liquid portion of the heat source unit side heat exchanger 3 is reduced and the high pressure is reduced. Control of the on-off valve 21 is performed under high pressure (here, the pressure sensor 1
When the detection pressure of 5) becomes higher than Pd1, it opens. On the contrary, in the open state, it is closed when the high pressure falls below Pd2 which is lower than Pd1. The difference between Pd1 and Pd2 is provided to prevent the refrigerant movement from becoming unstable due to frequent opening and closing operations.

Here, FIG. 4, which is the control flow of this embodiment, will be described. First, in step 23, the power is detected, and if the detected power W is larger than a predetermined power value WD, demand control is started (steps 24 and 25).
The demand signal transmission unit 11 transmits the demand signal to the operation control unit 12 via the transmission line according to an instruction from the demand control determination device 10 (step 26). In this embodiment, the operation control unit 12 receives the function of the opening control means and receives the demand signal to change the opening Sj of the flow rate control device 4 to the current opening Sj.
A predetermined opening smaller than * Sj is used. At this time, the compressor 1
The suction pressure of is reduced. However, the decrease in the low pressure is detected by the temperature of the thermistor 17, and if the low voltage is not lower than the predetermined value a in step 28, it is determined that the input is not sufficiently decreased, and the opening is decreased again in step 27. If the high pressure rises, the on-off valve 21 is opened as shown in FIG. 3 to prevent the power consumption of the compressor 1 from rising due to the high pressure rise. By reducing the opening degree of the flow rate control device 4 in this way, the power consumption can be reduced without stopping the compressor 1, the number of times of starting and stopping the compressor 1 can be reduced, and the capacity does not become zero. Therefore, the reliability of the refrigeration system can be sufficiently enhanced.

Example 2. FIG. 5 is a flow chart of a refrigeration / air-conditioning system during cooling according to an embodiment of the present invention. Since the refrigerant circuit diagram and the control block diagram are the same as those in the first embodiment, the description thereof will be omitted. Here, the description of FIG. 5 will be given taking the cooling operation as an example. First, the power monitoring device 9 detects the power consumption of the refrigeration system (step 2).
9). The power consumption W detected at this time is the first predetermined value W1.
It is determined in step 31 whether or not it is larger. If W>
If it is W1, the process proceeds to step 32. If W ≦ W1, the routine proceeds to step 33, where it is judged whether or not the demand signal is presently being transmitted, that is, whether or not a demand signal to be described later has already been transmitted. To send the demand end signal. In step 32, it is determined whether the power consumption W is larger than the second predetermined value W2. If W> W2, the process proceeds to step 36, but if W ≦ W2, the process proceeds to step 38, where it is judged that the demand level is the first stage, and step 39
Then, the demand signal 1 is transmitted. In step 36, it is judged that the demand level is the second stage, and in step 37 the demand signal 2 is transmitted. Here, it means that the demand level 2 has a higher power reduction demand than the demand level 1. In step 40, the operation control unit 12 sets the opening degree of the flow rate control device 4 to the initial opening degree Sj0 in step 41 if the signal sent is the demand end signal. Step 40
If the signal received in step 2 is the demand signal 2, the opening degree of the flow rate control device 4 is changed from the current opening degree Sj * to a predetermined value Δ in step 42.
Decrease by Sj2. After that, if the pressure Ps detected by the pressure sensor 15 is lower than the predetermined pressure a ₂ , the opening remains unchanged, but if Ps ≧ a ₂ , then ΔSj
Decrease the opening by 2. If the signal received at step 40 is the demand signal 1, at step 44 the flow rate control device 4
Is decreased from the current opening Sj * by a predetermined ΔSj1. After that, if the pressure Ps detected by the pressure sensor 15 is lower than the predetermined pressure a ₁ , the opening is kept as it is, but if Ps ≧ a ₁ , the opening is further reduced by ΔSj1. Here, ΔSj1 ≦ ΔSj2, and a ₁ > a
_The demand level 2 means that the demand level for reducing the power consumption by the demand is larger. In this way, the power consumption of the refrigerating / air-conditioning apparatus can be gradually reduced by gradually reducing the opening degree of the flow rate control device 4 according to the demand level here, and it is possible to perform finer control of power reduction. Become.

Example 3. FIG. 6 shows a control flow chart in the refrigeration system according to an embodiment of the invention of claim 3. Since the refrigerant circuit diagram and the control block diagram are the same as those in the first embodiment, the description thereof will be omitted. First, the power monitoring device 9 (FIG. 2) detects the power consumption of the refrigeration system (step 46). At step 47, it is determined whether the power consumption W detected at this time is larger than a predetermined value WD. If W> WD, the demand control determination device 10 determines that the demand has started in step 48, and transmits the demand signal in step 49. Further, the demand control determination device 10 is
The demand is started and the timing (T) is started (step 50). On the refrigeration system side, the operation control unit 12 determines whether a demand signal has been received (step 51). If it has been received, the operation controller 12 having the function of the opening control means determines in step 52 the maximum opening Sj of the flow control device 4.
max and minimum opening Sjmin are set to the current set opening Sjma
It is set smaller than x * and Sjmin * by ΔSj1 and ΔSj2, respectively. When the predetermined time Ta has passed (step 53), the demand end signal is transmitted as the demand end (step 54). In step 55, it is judged whether or not the demand end signal is received. If so, the process proceeds to step 56, where the maximum opening Sjma
x is set to a predetermined initial value Sjmax0, and the minimum opening Sjmin is set to a predetermined initial value Sjmin0. In this way, by setting the predetermined opening smaller than the maximum opening or the minimum opening currently set in the demand control,
When the current opening degree of the flow rate control device 4 is blocked by the maximum opening degree in order to increase the opening degree in terms of control, the maximum opening degree is reduced to forcefully reduce the opening degree. On the contrary, when the opening is controlled to be closed and the opening is blocked by the minimum opening, the opening can be reduced by reducing the minimum opening. As a result, the degree of opening is reduced, so the throttling effect is improved, the suction pressure of the compressor is reduced, and the power consumption of the compressor can be reduced without stopping the compressor. Therefore, the reliability of the compressor refrigeration system can be improved because the failure factor can be reduced.

Example 4. FIG. 7 is a flow chart of a refrigeration / air conditioning system during cooling according to an embodiment of the invention of claim 4. Since the refrigerant circuit diagram and the control block diagram are the same as those in the first embodiment, the description thereof will be omitted. Here, FIG. 7 will be described by taking the cooling operation as an example. First, the power monitoring device 9 detects the power consumption of the refrigeration system (step 5).
7). The power consumption W detected at this time is the first predetermined value W1.
In step 58, it is determined whether or not it is larger. If W>
If it is W1, the process proceeds to step 59. If W ≦ W1, the routine proceeds to step 60, where it is judged whether or not the demand signal is currently being transmitted, that is, whether or not a demand signal to be described later has already been transmitted. To send the demand end signal. In step 59, it is determined whether the power consumption W is larger than the second predetermined value W2. If W> W2, the process proceeds to step 63, but if W ≦ W2, the process proceeds to step 65 where it is determined that the demand level is the first stage, and step 66 is performed.
Then, the demand signal 1 is transmitted. In step 63, it is judged that the demand level is the second stage, and in step 64 the demand signal 2 is transmitted. Here, it means that the demand level 2 has a higher power reduction demand than the demand level 1. If the signal sent from the operation control unit 12 is the demand end signal in step 67, the operation control unit 12 having the function of the opening control means determines in step 68 that the flow rate control device 4 is operating.
The maximum opening set value is set to Sjmax0 which is an initial set value, and the minimum opening set value is set to Sjmin0 which is an initial set value.
If the signal received in step 67 is the demand signal 2, in step 69 the maximum opening set value of the flow rate control device 4 is reduced from the current set value Sjmax * by ΔSj3, and the minimum opening set value is set to the current set value Sjmin. Decrease by * Sj4 from *. The signal received in step 67 is the demand signal 1
If so, in step 70, the maximum opening set value of the flow rate control device 4 is reduced by ΔSj1 from the current set value Sjmax *, and the minimum opening set value is set by ΔSjmin * from the current set value Sjmin *.
Decrease by Sj2. At this time, ΔSj1 <ΔSj3,
There is a magnitude relationship of ΔSj2 <ΔSj4, and the maximum opening and minimum opening set values are also changed stepwise according to the level of the demand level. By setting the maximum opening or the minimum opening currently set for demand control to a smaller predetermined opening in this way, the current opening of the flow rate control device 4 is controlled to increase the maximum opening in order to increase the opening. If the maximum opening is reduced, the maximum opening is reduced to forcibly reduce the opening. On the contrary, when the opening is controlled to be closed by the minimum opening, the opening can be reduced by reducing the minimum opening. As a result, the degree of opening is reduced, so that the throttling effect is improved, the suction pressure of the compressor is reduced, and the power consumption of the compressor can be reduced without stopping the compressor. Since the set values of the opening and the minimum opening can be changed stepwise, fine control becomes possible. In this way, the reliability of the refrigeration / air conditioning system can be improved.

Example 5. FIG. 8 shows claims 5 and 6.
3 is a flowchart of an air conditioning system during cooling according to an embodiment of the invention of FIG. Since the refrigerant circuit diagram and the control block diagram are the same as those in the first embodiment, the description thereof will be omitted. Here, the description of FIG. 8 will be given by taking the cooling operation as an example. First, the power monitoring device 9 detects the power consumption of the air conditioning system (step 71). At step 72, it is determined whether the detected power consumption W is larger than the first predetermined value W1.
If W> W1, the process proceeds to step 73. If W ≦ W1, the routine proceeds to step 74, where it is judged whether or not there is a demand at present. If it is demand, it means that the demand has ended due to the power reduction (step 75), and a demand end signal is transmitted at step 76. In step 73, it is determined whether the power consumption W is larger than the second predetermined value W2.
If W> W2, the routine proceeds to step 77, but if W ≦ W2, the routine proceeds to step 79, where it is determined that the demand level is the first stage, and the demand signal 1 is transmitted at step 80. In step 77, it is judged that the demand level is the second stage, and in step 78 the demand signal 2 is transmitted. This means that the demand level 2 requires a larger amount of power reduction than the demand level 1. In this embodiment, the operation control unit 12
Has a function as a target superheat control means and a target supercooling degree control means.
If the signal is the signal demand end signal sent from, the target refrigerant superheat degree SHm at the outlet of the indoor heat exchanger 5 acting as the evaporator is set to the normal level SH0. The refrigerant superheat degree SH is the thermistor 1 that constitutes the superheat detection means.
It is calculated by the following formula based on the values detected in 3 and 14. SH = t13−t14 where t13: detection temperature of the thermistor 13 t14: detection temperature of the thermistor 14 If the next received signal is the demand signal 1, step 8
In step 4, the target superheat degree control means increases the target value of the refrigerant superheat degree from the normal level SH0 by ΔSH1. If the signal is the demand signal 2, the process proceeds to step 83,
The target value of the degree of superheat is increased from SH0 by ΔSH2.
In this way, by setting the target value of the refrigerant superheat degree at the evaporator outlet to a larger predetermined target value, the opening degree of the flow rate control device 4 is indirectly controlled via the opening degree control means. Therefore, the power consumption of the compressor can be reduced without reducing the suction pressure of the compressor and stopping the compressor. In addition, the number of times of starting and stopping the compressor can be reduced. Then, the demand control can be performed stepwise by changing the target value stepwise according to the required level of the power reduction amount. Since the compressor is not stopped in this way, demand control can be performed without reducing the capacity of the refrigeration system to 0, and fine control can be performed by performing demand control stepwise, so the operating state of the refrigerant system suddenly increases during demand control. Does not change, the performance and reliability of the air conditioning system can be sufficiently enhanced. Further, during the heating operation, the refrigerant supercooling degree at the refrigerant outlet side of the utilization side heat exchanger, that is, the inlet of the flow rate control device 4 is obtained from the detection value of the thermistor 14a and the detection value of the thermistor 15, and this subcooling degree is the target. The opening degree control means controls the opening degree of the flow rate control device 4 so that the degree of supercooling is SCm. As in the case of the cooling operation, the target value of the degree of supercooling is gradually increased to a larger predetermined value in accordance with the demand level output from the demand control unit 20, so that the flow rate control device is controlled through the opening degree control means. Since the opening of No. 4 is controlled to be reduced, the suction pressure of the compressor 1 is reduced, and the power consumption can be reduced. By controlling as described above, the same effect as in the case of cooling can be obtained.

Example 6. FIG. 9 shows claims 7 and 8.
It is a refrigerant circuit diagram in one example. 10 is a control block diagram thereof, and FIG. 11 is a control flowchart diagram. The refrigerant circuit diagram shown in FIG. 9 has two indoor units in parallel as compared with the conventional example. For this reason, the flow control device 4a,
4b, two indoor heat exchangers 5a and 5b as use-side heat exchangers, and thermistors 13a, 13b, 14a and 1
4b and two each. The compressor 1 is a compressor whose capacity can be controlled. Further, as shown in the first embodiment, it also has a low pressure saturation temperature generation circuit 16 and a thermistor 17. The movement of the refrigerant is the same as that of the conventional example, and the movement of the refrigerant in the low pressure saturation temperature generation circuit is the same as that of the first embodiment, and therefore the description thereof is omitted here. In the control block diagram shown in FIG. 10, 20 is a demand control unit, and a timer 85,
The demand control determination device 10 and the demand signal transmission unit 11 are included. These 10, 11, and 85 are installed in a place apart from the heat source unit 7 and the air conditioners of the indoor units 8a and 8b, are connected to the air conditioner by a transmission line, and if necessary, a demand signal is controlled to operate the refrigeration system. To the section 12.
Reference numeral 12 denotes an operation control unit of the refrigeration system, which is the thermistor 1
3a, 13b, 14a, 14b, 17 and pressure sensor 15
Receives input from compressor 1 and flow controller 4
a, 4b, and the four-way switching valve 2 are controlled. The timer 85 measures time, transmits a demand signal at a preset demand start time, and further transmits a demand end signal at a preset demand end time.
This is to predict the daily power amount in advance, and try to reduce the power consumption by performing demand control during a certain time period. In this case, the amount of electric power, which is the integrated amount, is regarded as important rather than the instantaneous amount of electric power, and the demand control is made so as not to exceed the amount of electric power contracted with the electric power company. However, for example, when the outside air is a little low in the middle period or summer, the power consumption is not so large that the demand control may be performed even when it is not necessary to stop the air conditioner. The remote controllers 86 and 87 are used to send operation / stop signals for the indoor units 5a and 5b to the operation control unit 12, respectively.

Here, the control flowchart of FIG. 11 will be described. FIG. 11 assumes cooling operation. First, the clock time of the timer 85 is checked in step 86. When the time reaches the demand start set time TS, the demand is started (step 87), and the demand signal is transmitted (step 88). In this embodiment, the operation control unit 12 receives the function of the capacity control means and receives the demand signal to set the set maximum value of the operating frequency of the compressor 1 to the initial set maximum value F.
It is set to a value smaller than max0 by ΔFmax (step 89). Then, in step 90, the present frequencies F * and Fm
Ax is compared, and if F * is large, in step 91 the frequency is reduced to the changed Fmax to reduce power consumption. When the frequency is reduced in step 92, the operation control unit 12 reduces the frequency and then measures the time T ′ to suspend the control until the time Ta at which the refrigerant state is considered to be substantially stable. Reducing the capacity of the compressor in this way is also one of demand control. Then, in step 93, the number N of operating indoor units is judged, and if N> 1, that is, when all the units are operating in this embodiment, the frequency of the compressor 1 is lowered and the throttle is loosened with respect to the flow rate of the refrigerant, so that the pressure is low. Is determined to have increased, and the target degree of superheat is increased by ΔSHm in step 94. Number of operating vehicles 1 in step 94
In the case of the table (N ≦ 1), the routine proceeds to step 98, where the pressure P (t17) converted from the reading t17 of the thermistor 17 which is the pressure detecting means is equal to or more than the predetermined pressure P1,
In this embodiment, the target superheat degree control means increases the target superheat degree SHm by ΔSHm in step 94, and the opening degree of the flow rate control device is reduced through the opening degree control means to reduce the low pressure. If it is lower than P1, there is no particular problem of lubricating oil discharge, and the target degree of superheat is set to the initial SHo (step 99). Therefore, the opening degree of the flow rate control device 4a or 4b is not reduced. In this way, the process returns to step 86, and the time check of the timer 18 is performed again. Next, at step 87, when the time measurement time is not Ts, the time measurement is judged again at step 95. The timer 85 measures the demand control end set time T
If it is E, the routine proceeds to step 96, where the demand end signal is transmitted. When the demand end signal is received, the operation control unit 12 first sets the maximum frequency of the compressor 1 to the original Fm.
Ax0 is set (step 97). Then, the process proceeds to step 98, and if the low pressure falls below a predetermined pressure, the initial refrigerant superheat degree SHo is set. When the number of indoor units operating in a multi-type air conditioner equipped with multiple indoor units is large in this way, the low pressure rises and the amount of oil discharged from the compressor increases, resulting in damage to the compressor. There is a fear that the target degree of superheat S
Increasing Hm indirectly reduces the opening of the flow rate control device of the indoor unit and lowers the low pressure to reduce power consumption and suppress the discharge of lubricating oil, and prevent damage to the compressor. Therefore, the reliability of the air conditioning system can be sufficiently enhanced.

Example 7. FIG. 12 is a refrigerant circuit diagram of an embodiment according to the inventions of claims 6 and 7, and is the same as that of embodiment 6. FIG. 13 is a control block diagram of this embodiment.
FIG. 14 is a control flowchart of this embodiment. FIG.
In, there are four control parts, which are the demand control part 20, the heat source device 7, and the indoor units 8a and 8b. As shown in FIG. 13, the demand control unit 20 transmits a signal to the operation control unit 12 in the heat source unit 7. An operation control unit 12 is provided in the heat source unit 7 and has an input to the thermistor 17, a pressure sensor 15, a four-way switching valve 2 and an output to the compressor 1 whose capacity can be controlled. Further, the operation control unit 1 is provided in the indoor unit 8a.
2a, which has inputs of the thermistor 13a and thermistor 14a and an output of the flow control device 4a, and starts and stops by a signal from the remote controller 19a. Then, during the cooling operation, the refrigerant superheat degree is obtained from the inputs of the thermistors 13a and 14a, and the flow rate control device 4a is controlled so as to attain the target superheat degree SHm.
At the time of heating, the value of the thermistor 14a and the input value of the pressure sensor 15 are received from the operation control unit 12 of the heat source unit 7, the refrigerant supercooling degree at the inlet of the flow rate control device 4a is obtained, and the target supercooling degree S is obtained.
The opening degree of the flow rate control device 4a is adjusted so as to be Cm. The operation control unit 12b performs the same control as 12a. Here, the operation and stop of the heat source unit 7 and the indoor units 8a and 8b will be briefly described. First, a driving signal is sent from the remote controller 86 to the driving control unit 12a. Based on this signal, the operation control unit 12a sends an operation signal to the operation control unit 12 to start controlling the flow rate control device 4a. The operation control unit 12 determines that the operation is based on the signal sent from the operation control unit 12a,
The compressor 1 is operated, and cooling or heating operation starts. However, the cooling operation and the heating operation are determined by the operation of the four-way switching valve 2, which is determined by the operation control unit 12 based on the cooling signal or the heating signal sent from the operation control unit 12a or 12b. Further, during the cooling operation, the heat source unit side heat exchanger 3 is a condenser, and the indoor side heat exchangers 5a and 5b are evaporators, and during heating, the relationship between these condensers and evaporators is reversed.

Next, the control flowchart in this embodiment will be described with reference to FIG. Here, description will be given based on the operation during cooling. The demand control unit 20 and the operation control units 12, 12a, 1 are arranged so that the control portion can be easily understood.
Each of 2b is divided. In step 121, the timer 5 is counted, and after 30 minutes have elapsed, it is determined that demand control has started (steps 122 and 123). Then, in step 124, the demand signal transmission unit 11 causes the operation control unit 1 to
2 to the demand signal. After the transmission, the timer 85 is once cleared at step 125 and the counting is started again. The reason why the demand signal is periodically transmitted is, for example, that the operation control units 12a and 12b have a demand control end function (explanation omitted), and the demand control is continued even when the demand control is arbitrarily ended at a certain time. This is for the purpose of In this embodiment, the operation control unit 12 having the function of the capacity control means receives the demand signal and sets the upper limit of the frequency of the compressor 1 from the initial value Fmax0 to ΔFma.
It is reduced by x (step 126). In this way, when the compressor 1 is operating near the maximum frequency Fmax0, the frequency is forcibly reduced and the power consumption is reduced. Next, in step 127, the demand level (DL) is set as the degree of need for lowering the suction pressure, and it is set to 0 which means a non-demand condition (step 51). Next step 1
At 28, it is determined whether the detected temperature t17 of the low pressure saturation temperature thermistor 17 is higher than a predetermined value t1. Here, t1 is the saturation temperature of the suction pressure at which the amount of lubricating oil discharged from the compressor 1 increases and the compressor 1 may be damaged. If t17> t1, the routine proceeds to step 132, where DL is increased by 1 to increase the suction pressure reduction requirement. If t17> t1, step 1
At 35, the suction pressure is not a problem and DL is lowered by 1. DL
The upper and lower limits of the upper limit are 2, and the lower limit is 0. Therefore, in steps 133 and 136, it is determined whether the values are outside the upper and lower limits, respectively, and the corrections are made in steps 134 and 137, respectively. In step 138, the operation control unit 12 of each indoor unit 8a, 8b sets the value of DL thus set.
a and 12b (step 138). After transmission, the timer T0 is reset to start counting (step 13
1). Then, in step 129, when the timer has passed 10 minutes, the flow returns to the determination of the suction pressure again. Step 131,
The reason for waiting 10 minutes at 130 and 129 is that it takes time for the state of the refrigerant to change after the DL signal is transmitted and the flow rate control devices 4a and 4b are operated on the indoor unit side, and the signal is frequently used. To prevent the control from being disturbed. The operation control units 12a and 12b on the indoor side determine respective target values of the refrigerant superheat degree based on the DL signals sent. In this embodiment, the operation control unit 1
2a has a function as a target superheat control means,
The DL signal is determined in step 146, and when DL = 0, the target superheat degree SHma is set to the normal target value SHm0a (step 145). SHma = SH when DL = 1
1a and DL = 2, SHma = SH2a and S
There is a relationship of H2a>SH1a> SH0a. Here, the subscript a of the superheat degree symbol means a set value unique to the indoor unit 8a. This is because the appropriate target value changes depending on the shape and capacity of the indoor unit. In this way, when the suction pressure of the compressor 1 is higher than the predetermined value, the target superheat degree is changed at two levels other than the normal level, so that the flow control device 4a is controlled through the opening control means of the operation control unit 12a. Since the opening is controlled in the closing direction, the suction pressure decreases, and even when the frequency of the compressor 1 decreases due to demand control, the lubricating oil discharge amount does not increase due to the increase of the suction pressure and the compressor 1 is not damaged, so that the air conditioning system The reliability of can be significantly increased.

Example 8. In the seventh embodiment, the suction pressure of the compressor 1 is detected from the low pressure saturation temperature by the thermistor 17, but the suction pressure of the compressor whose capacity can be controlled can be predicted to some extent by the operating capacity of the compressor, that is, the operating frequency, by experiments or the like. Generally, as the frequency of the compressor 1 increases, the suction pressure tends to decrease. Therefore, if the predetermined frequency F1 is set empirically as in step 128a of FIG. Even if the pressure detecting means determines that the pressure is the pressure that is discharged more than necessary, the same effect as that of the seventh embodiment is exhibited.

Example 9. FIG. 16 is a refrigerant circuit diagram of a refrigeration system of an embodiment according to the invention of claim 1. FIG. 17 is a control block diagram thereof, and FIG. 18 is a control flow chart diagram thereof. In FIG. 16, most of it is the same as the conventional example. In addition to the conventional example, the four-way switching valve 2 and the accumulator 6 are added.
A flow rate control device 147, a bypass pipe 148 in parallel with the flow rate control device 147, and a pressure sensor 149 for detecting the suction pressure of the compressor 1 are provided in between. Since the flow of the refrigerant is the same as that of the conventional example, the description thereof will be omitted here. However, by adjusting the flow rate control device 147, the suction pressure of the compressor 1 is adjusted, so to speak, as a variable resistance, and the resistance pipe 148 is If the flow controller 147 fails and the fluid stops flowing there, it is provided to ensure a minimum path for the fluid. However, in order to bring out the effect of the flow rate control device 147, the diameter of the resistance pipe 148 is not increased more than necessary. Next, a control flowchart of this embodiment will be described with reference to FIG. Step 151
Then, the power monitoring device 9 detects the power consumption W of the refrigeration system. In step 152, if it is detected that the power consumption W is larger than WD which is the demand start condition, the demand signal is transmitted in step 153 (step 154). When receiving the demand signal, the operation control unit 12 having the function as the opening control means reduces the opening Kj of the flow rate control device 147 by ΔKj from the current predetermined opening Kj0 in step 155. As a result, the suction pressure of the compressor 1 is reduced and the power consumption is reduced. Next, at step 156, the compressor 1 is operated by the pressure sensor 161.
The intake pressure Ps is determined to be smaller than the intake pressure P1 at which the power consumption of the compressor 1 can be determined to be as small as necessary. However, if the suction pressure is lowered more than necessary, the discharge temperature of the compressor may be increased and the compressor 1 may be damaged, so P1 is set assuming such a dangerous pressure level. If there is a concern that the discharge temperature will rise, a protection control such that a thermistor is separately provided on the discharge side of the compressor 1 (not shown) and the opening degree of the flow rate control device 147 is opened when the temperature exceeds a predetermined value is provided. Means for providing may be considered. Thus in step 156 if P
If S ≧ P1, the opening degree is reduced again in step 155 to reduce the suction pressure. If PS <P1, the timer 162 is set in step 157, and in steps 158 and 159, such demand control is performed until the predetermined time T1 has passed. In step 160, the opening degree of the flow rate control device 147 is returned to the original predetermined opening degree Kj0 and the demand control is ended. As described above, the position of the flow rate control device 147 is between the four-way switching valve 2 and the accumulator 6, and is located downstream of the flow rate control device 4 and always corresponds to the low pressure portion during either cooling or heating. By reducing the opening degree, the suction pressure of the compressor 1 decreases and the high pressure does not increase. Therefore, the demand control can be performed without stopping the compressor 1, so that the electric power can be reduced, and the capacity of the refrigerating apparatus is reduced due to the decrease in the refrigerant flow rate due to the decrease in the suction pressure, but the function of the refrigerating apparatus is not zero. It is not necessary to damage all of them, and it is possible to prevent a failure due to an increase in the number of times of starting and stopping the compressor, and it is possible to sufficiently enhance the reliability of the refrigeration system.

Example 10. FIG. 19 is a refrigerant circuit diagram of the refrigerating apparatus in one embodiment of claim 7 and claim 8.
20 is a control block diagram thereof, and FIG. 21 is a control flowchart diagram. The refrigerant circuit diagram of the refrigerating apparatus shown in FIG. 19 has two indoor units in parallel as compared with the conventional example. Therefore, there are two flow rate control devices 4a and 4b, indoor side (use side) heat exchangers 5a and 5b, and thermistors 13a and 13b.
It has two each of b, 14a, and 14b. 16
Reference numerals 5 and 166 denote blowers provided in the indoor units 8a and 8b, respectively. The compressor 1 is a compressor whose capacity can be controlled. Further, as shown in the first embodiment, it also has a low pressure saturation temperature generation circuit 16 and a thermistor 17. The movement of the refrigerant is the same as that of the conventional example, and the movement of the refrigerant in the low pressure saturation temperature generation circuit 16 is the same as that of the first embodiment, and therefore the description thereof is omitted here. In FIG. 20, reference numeral 20 denotes a demand control unit, which includes a timer 85, a demand control determination device 10, and a demand signal transmission unit 11, and is installed at a place apart from the refrigeration device and connected to the refrigeration device by a transmission line. Then, the demand signal is transmitted to the operation control unit 12 of the refrigeration system as needed. Reference numeral 12 denotes an operation control unit of the refrigeration system, which receives inputs from the thermistors 13a, 13b, 14a, 14b, 17 and the pressure sensor 15 and controls the compressor 1, the flow rate control devices 4a, 4b, and the four-way switching valve 2. The timer 85 measures time, transmits a demand signal at a preset demand start time, and further transmits a demand end signal at a preset demand end time. This is to predict the daily power amount in advance, and try to reduce the power consumption by performing demand control during a certain time period. In this case, not the instantaneous electric power, but the electric power which is the integrated amount is regarded as important, and the demand control is made so as not to exceed the contracted electric power amount with the electric power company. For example, when the outside air is a little low in the middle period or in the summer, the power consumption is not so large that the demand control may be performed even if it is not necessary to stop the refrigeration system. The remote controllers 86 and 87 are used to send operation / stop signals for the indoor units 5a and 5b to the operation control unit 12, respectively.

Next, the capacity of the indoor unit in this embodiment will be described. Generally, the indoor unit is composed of a heat exchanger and, in the case of air cooling, a blower (this embodiment). The heat exchange capacity Q is determined by the size (shape) A of the heat exchanger and the air volume V by the blower. That is, Q = f (A, V) f: function. The f is naturally different depending on the amount of heat exchange on the refrigerant side and the amount of heat exchange on the air side, but at least the size (surface area, volume) A and the air volume V increase and the heat exchange capacity also increases. To increase. For this reason, the heat exchange capacity of the indoor unit will be represented by an index according to the size of the variable taking into consideration the shape of the heat exchanger, the air volume, or both. In this embodiment, the index is Qj (j = 1, 2) and the subscripts correspond to the indoor units 8a and 8b. Here, the control flowchart of FIG. 21 will be described. FIG. 21 assumes a cooling operation. First, the time measured by the timer 85 is checked in step 86. When the time reaches the demand start set time TS, the demand is started (step 87), and the demand signal is transmitted (step 88). In this embodiment, the operation control unit 12 functioning as the capacity control means sets the set maximum value of the operating frequency of the compressor 1 to a value smaller by ΔFmax than the initial set maximum value Fmax0 by receiving the demand signal (step 89). Then, in step 90, the current frequency F * is compared with Fmax, and if F * is large, the frequency is lowered to the changed Fmax in step 91. When the frequency is reduced in step 92, the frequency is reduced and then the time T'is measured to continue the control until the time Ta at which the refrigerant state is considered to be substantially stable. Then, in step 93a, the operation control unit 12 determines the operating capacity of the usage-side heat exchanger in the refrigerant circuit based on the total Qj (ΣQj) of the indoor units in operation as the operating capacity of the indoor unit, and ΣQ
When j is larger than the predetermined capacity a, it is determined that the use side heat exchange capacity is too large and the low pressure has increased with respect to the refrigerant flow rate for the frequency reduction of the compressor 1, and in this embodiment, the target superheat degree control is performed. In step 94, the means increases the target superheat degree by ΔSHm. When the operating capacity is less than the predetermined capacity a in step 93a, it is judged that the heat exchange capacity on the utilization side is appropriate with respect to the capacity of the compressor 1, and the process proceeds to step 98. Here, from the reading t17 of the thermistor 17 If the converted low pressure P (t17) is higher than the predetermined pressure P1, the target superheat degree SHm is increased by ΔSHm in step 94 to reduce the low pressure. If it is lower than P1, there is no particular problem of lubricating oil discharge, and the target degree of superheat is set to the initial SH0 (step 99). By increasing the target degree of superheat in step 94, the opening degree control means reduces the opening degree of the flow rate control device to reduce the low pressure. In this way, the process returns to step 86, and the time measurement of the timer 85 is checked again. Next, at step 87, when the time measurement time is not Ts, the time measurement is judged again at step 95. If the time measured by the timer 95 is the demand control end set time TE, step 9
In step 6, the demand end signal is transmitted. When the demand end signal is received, the operation control unit 12 first determines the compressor 1
The maximum frequency of is set to the original Fmax0 (step 9
7). Then, after that, the routine proceeds to step 98, and when the low pressure falls below a predetermined pressure, the initial refrigerant superheat degree SH0 is set. In this way, when demand control is performed to reduce the maximum frequency of the compressor in a multi-type refrigeration system equipped with multiple indoor units, etc., when the operating indoor unit has a large capacity, the low pressure rises. Since the amount of oil discharged from the compressor increases, the compressor may be damaged and the target superheat degree SH
By raising m, the opening degree of the flow rate control device of the indoor unit is indirectly reduced, and by lowering the low pressure, the discharge of lubricating oil can be suppressed and damage to the compressor can be prevented. Therefore, the reliability of the refrigeration system can be sufficiently enhanced.

Example 11. In the above embodiment, the demand control unit 20 automatically determines the power consumption or time, but as shown in FIG. 22, for example, a manual demand level setting switch 171 and a demand signal transmission switch 172 are provided. There is such an operation control unit 170, the demand level is set in step 1c as shown in FIG. 23, and the demand signal transmission switch 1 is set in step 2c.
When 72 is turned on, a similar effect is exhibited in the case of transmitting a demand signal. In this case, switch 1
The operation of 72 is artificially performed by, for example, the operation manager of the refrigeration / air conditioning system.

[0042]

Since the present invention is constructed as described above, it has the following effects. The opening degree control means reduces the opening degree of the flow rate control device based on the output from the demand control section to reduce the suction pressure of the compressor, thereby reducing the power consumption of the compressor. Therefore, since the power consumption of the compressor can be reduced without stopping the compressor, the capacity of the refrigeration / air conditioning system decreases due to the decrease in the refrigerant flow rate due to the decrease in the suction pressure, but it is not 0.
It does not impair the function of the air conditioning system. Further, it is possible to prevent a failure due to the number of times the compressor starts and stops. If the opening degree of the flow rate control device is controlled stepwise, the suction pressure of the compressor is also lowered stepwise and the suction pressure control is performed stepwise, so that finer control can be performed. In this way, the performance and reliability of the refrigeration / air conditioning system can be significantly improved.

Further, based on the output of the demand control unit, by setting at least one of the currently set maximum opening or minimum opening to a smaller predetermined set opening, the flow control device If the current opening degree is blocked by the maximum opening degree in order to increase the controllable opening degree, the maximum opening degree is reduced to forcefully reduce the opening degree. On the contrary, when the opening is controlled to be closed by the minimum opening, the opening can be reduced by reducing the minimum opening.
As a result, the degree of opening is reduced, the throttling effect is enhanced, the suction pressure of the compressor is reduced, and the power consumption of the compressor can be reduced. In this way, demand control can be performed without stopping the compressor. Then, when temporarily reducing the current opening itself, the opening may increase again depending on the control over time, or when the current opening is fixed to a smaller opening. Although the controllability is lost, if the maximum opening or the minimum opening is reduced, the opening can be reduced while maintaining the controllability. When the maximum opening amount or the minimum opening amount of the flow rate control device is controlled in a stepwise manner, the suction pressure drop can be controlled in a stepwise manner, so that the power consumption can be finely controlled. In this way, it becomes possible to sufficiently enhance the controllability and reliability of the refrigeration / air conditioning system.

Further, the target superheat degree control means or the target supercooling degree control means sets the target value to a larger predetermined value based on the output of the demand control section, so that the opening degree of the flow rate control device is indirectly controlled. Is controlled to be small, the suction pressure of the compressor is reduced and the power consumption of the compressor can be reduced without stopping the compressor. Then, the target value can be changed stepwise according to the magnitude of the output from the demand control unit to perform fine control.
In this way, the performance and reliability of the refrigeration / air conditioning system can be improved.

Further, when the capacity control means reduces the capacity of the compressor by the output of the demand control part and the suction pressure of the compressor rises, the opening degree control means reduces the opening degree of the flow rate control device. The suction pressure can be reduced by this, the problem of damaging the compressor due to an increase in the amount of lubricating oil discharged is eliminated.If the suction pressure, which is a problem, has not been reached, the suction pressure is forcibly reduced to lower the capacity. You don't have to. In this way, the control most needed for the refrigeration / air conditioning system can be performed according to the situation.
The reliability of the air conditioning system can be sufficiently enhanced.

Further, when the capacity control means reduces the capacity of the compressor by the output of the demand control section, and the total operating capacity of the heat exchanger on the use side is equal to or more than a predetermined capacity, the opening control means controls the flow rate control device. By reducing the opening of the compressor, the increase in the amount of oil discharged from the compressor due to the rise in the low pressure is suppressed to prevent damage to the compressor, and a highly reliable refrigeration / air conditioning system is obtained. be able to.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram of a first embodiment.

FIG. 2 is a control block diagram of the first embodiment.

FIG. 3 is a diagram showing an operation of the on-off valve 21 according to the first embodiment.

FIG. 4 is a control flowchart of the first embodiment.

FIG. 5 is a control flowchart of the second embodiment.

FIG. 6 is a control flowchart of the third embodiment.

FIG. 7 is a control flowchart of the fourth embodiment.

FIG. 8 is a control flowchart of the fifth embodiment.

FIG. 9 is a refrigerant circuit diagram of the sixth embodiment.

FIG. 10 is a control block diagram of the sixth embodiment.

FIG. 11 is a control flowchart of the sixth embodiment.

FIG. 12 is a refrigerant circuit diagram of Example 7.

FIG. 13 is a control block diagram of the seventh embodiment.

FIG. 14 is a control flowchart of the seventh embodiment.

FIG. 15 is a control flowchart of the eighth embodiment.

16 is a refrigerant circuit diagram of Example 9. FIG.

FIG. 17 is a control block diagram of the ninth embodiment.

FIG. 18 is a control flowchart of the ninth embodiment.

FIG. 19 is a refrigerant circuit diagram of Example 10.

FIG. 20 is a control block diagram of the tenth embodiment.

FIG. 21 is a control flowchart of the tenth embodiment.

FIG. 22 is a control block diagram of the eleventh embodiment.

FIG. 23 is a control flowchart of the eleventh embodiment.

FIG. 24 is a refrigerant circuit diagram of a conventional example.

FIG. 25 is a control block diagram of a conventional example.

FIG. 26 is a control flowchart of a conventional example.

FIG. 27 is a control flowchart of a conventional example.

[Explanation of reference numerals] 1 compressor 3 heat source side heat exchanger 4 flow rate control device 4a flow rate control device 4b flow rate control device 5 use side heat exchanger 5a use side heat exchanger 5b use side heat exchanger 12 operation control unit 20 Demand control unit

Claims (8)

[Claims] 1. A refrigeration / air-conditioning apparatus equipped with a refrigerant circuit formed by connecting a compressor / heat-source-side heat exchanger, a flow rate controller, a usage-side heat exchanger, and the like, and is consumed by the refrigeration / air conditioning apparatus. A refrigeration / air-conditioning system comprising: a demand control unit that reduces the amount of electric power; and an opening control unit that reduces the opening of the flow rate control device based on the output of the demand control unit. 2. The refrigeration / air conditioning system according to claim 1, wherein the opening degree of the flow rate control device is changed stepwise in accordance with the degree of power reduction request from the demand control unit. 3. A refrigeration / air-conditioning system equipped with a refrigerant circuit comprising a compressor, a heat-source-side heat exchanger, a flow rate control device, a utilization-side heat exchanger, etc., and is consumed by the refrigeration / air-conditioning system. A demand control unit that reduces the amount of electric power and an opening control unit that reduces at least one of the maximum opening and the minimum opening of the flow rate control device by a predetermined value based on the output of the demand control unit. A refrigeration / air conditioning system characterized by being equipped. 4. The opening degree of at least one of the maximum opening degree and the minimum opening degree of the flow rate control device is stepwise changed according to the degree of power reduction demand from the demand control unit. Refrigeration / air-conditioning system according to item 3. 5. A refrigerating / air-conditioning apparatus equipped with a refrigerant circuit formed by connecting a compressor, a heat source side heat exchanger, a flow rate control device, a use side heat exchanger and the like, and the above during cooling operation or overheat operation. A superheat degree on the refrigerant outflow side of the utilization side heat exchanger, or a superheat degree detecting means for detecting a supercooling degree, or a supercooling degree detecting means,
The degree of superheat or degree of supercool detected by the degree of superheat detection means or degree of supercool detection is compared with a preset target value, and the degree of superheat formula or the degree of temperature cooling becomes the target value. An opening control means for controlling the opening of the flow rate control device,
A demand control unit that reduces the amount of power consumed by the refrigeration / air-conditioning apparatus, and a target superheat degree that sets a target value of the superheat degree or the supercooling degree to a larger predetermined value based on the output of the demand control unit, or Is a refrigeration / air-conditioning system including a target supercooling degree control means. 6. The method according to claim 5, wherein at least one of the target values of the degree of superheat or the degree of subcool is changed stepwise in accordance with the degree of power reduction demand from the demand controller. Refrigeration / air-conditioning system according to the item. 7. A refrigeration / air-conditioning apparatus equipped with a refrigerant circuit including a compressor, a heat-source-side heat exchanger, a flow rate controller, a utilization-side heat exchanger, and the like, and the refrigeration / air-conditioning apparatus consumes the air. A demand control unit that reduces the amount of electric power, a capacity control unit that reduces the compressor capacity based on the output of the demand control unit, a pressure detection unit that detects the suction side pressure of the compressor, and a pressure detection unit that detects the pressure. A refrigeration / air-conditioning system comprising: an opening control means for reducing the opening of the flow control device when the applied pressure is equal to or higher than a predetermined pressure. 8. A refrigerating / air-conditioning apparatus having a refrigerant circuit formed by connecting a compressor, a heat source side heat exchanger, a flow rate control device, a utilization side heat exchanger, and the like, and power consumed by the refrigerating / air conditioning apparatus. The demand control unit for reducing the amount, the capacity control unit for reducing the compressor capacity based on the output from the demand control unit, and the flow control device when the total operating capacity of the utilization side heat exchanger is equal to or more than a predetermined capacity. An opening degree control means for reducing the opening degree of the refrigeration / air conditioning system.