JP2005241195A - Air conditioning refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioning refrigerator capable of increasing efficiency of energy consumption. <P>SOLUTION: This air conditioning refrigerator is provided with an air conditioning system part provided with a compressor 13 for air conditioning, a heat exchanger 16 on a heat source side, and a heat exchanger 27 on a use side to perform air conditioning in one room by the heat exchanger 27 on the use side, a refrigerating system part provided with a compressor for cooling, a condenser, and an evaporator to cool the inside of cooling storage facility arranged in one room by the evaporator, and a cascade heat exchanger 21 for performing heat exchange between refrigerant on a low pressure side of the air conditioning system part and refrigerant on a high pressure side of the refrigerating system part. A temperature sensor 129 for controlling air conditioning is provided in a section where air conditioning load or fluctuation of air conditioning load is high in one room. This refrigerator is provided with a control means for continuing operation of the compressor for air conditioning when the air conditioning system part reaches an air conditioning thermostat turning-off in accordance with a value detected by the temperature sensor and controlling flow rate of refrigerant on the low pressure side of the air conditioning system part which flows into the cascade heat exchanger 21. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an air-conditioning refrigeration apparatus for cooling the interior of a cooling storage facility while air-conditioning a room in a store or the like, for example.

Conventionally, the inside (indoor) of a store such as a convenience store is air-conditioned and air-conditioned by an air conditioner. In addition, in the store, there are open showcases for refrigeration or refrigeration for displaying and selling products, and showcases (cooling storage facilities) with doors, and these are cooled by the refrigerator (for example, Patent Document 1).
JP 2002-174470 A

  In this type of air-conditioning refrigeration system, the operation of the air-conditioning system unit and the operation of the cooling system unit are merely controlled according to the air-conditioning load and the cooling facility load, respectively, and the energy consumption efficiency of the entire system (COP, etc.) Cannot be improved.

  This invention is made | formed in view of the situation mentioned above, and it aims at providing the air-conditioning freezing apparatus which can raise energy consumption efficiency.

  The present invention includes an air conditioning system unit that includes an air conditioning compressor, a heat source side heat exchanger, and a usage side heat exchanger, and performs air conditioning in one room by the usage side heat exchanger, a cooling compressor, a condenser, A refrigeration system unit that includes an evaporator and cools the inside of the cooling storage facility disposed in the one room by the evaporator, a low-pressure side refrigerant of the air-conditioning system unit, and a high-pressure side of the refrigeration system unit A cascade heat exchanger for exchanging heat between refrigerants, and an air conditioning load in the one room or a temperature sensor for air conditioning control in a portion where the air conditioning load varies greatly, and a detection value of the temperature sensor And a control means for controlling the refrigerant flow rate on the low pressure side of the air conditioning system in the cascade heat exchanger.

  In the present invention, since the air conditioning load in one room or the temperature sensor for air conditioning control is provided in a part where the fluctuation of the air conditioning load is large, the operation of the air conditioning compressor is controlled according to the side where the air conditioning load is large. Or, since fluctuations in the air conditioning load are detected quickly, the air conditioning compressor is operated and controlled as the temperature in the one room rises and falls. It stabilizes quickly.

  After the temperature in one room is stabilized, the refrigerant flowing to the use side heat exchanger is stopped, and the refrigerant from the air conditioning compressor is allowed to flow to the cascade heat exchanger. When the refrigerant flow rate on the low pressure side of the air conditioning system in this cascade heat exchanger increases, heat exchange is promoted between the low pressure side refrigerant of the air conditioning system unit and the high pressure side refrigerant of the refrigeration system unit. The load on the refrigeration side is stabilized and the operation is stabilized. Usually, when comparing the energy consumption efficiency of the air conditioning system unit and the energy consumption efficiency of the refrigeration system unit, the energy consumption efficiency of the air conditioning system unit is excellent, so when heat exchange in the cascade heat exchanger is promoted, Accordingly, the energy consumption efficiency of the entire system can be improved.

  In this case, when the air conditioning compressor is operated during the cooling thermo-off, the rotation frequency may be controlled within a predetermined frequency range.

  In addition, the air conditioning system unit is configured for the air conditioning to set a temperature difference between the inlet temperature and the outlet temperature of the refrigerant on the high pressure side of the cooling refrigerant circuit that is passed through the cascade heat exchanger to a preset temperature difference. A target rotational frequency of the compressor is obtained, and when the target rotational frequency is within the predetermined frequency range, the rotational frequency of the air conditioning compressor is controlled to the target rotational frequency, while the rotational frequency is the predetermined rotational frequency. When the temperature difference is substantially equal to the lower limit frequency of the frequency, the temperature difference is greater than or equal to a predetermined temperature than the set temperature difference, and the rotation frequency substantially matches the upper limit frequency of the predetermined frequency, and the temperature difference is the setting When the temperature difference is equal to or lower than a predetermined temperature, the operation of the air conditioning compressor may be stopped.

  Further, the air conditioning system section may adjust the target rotation frequency so that the outlet temperature of the refrigerant on the high-pressure side of the cooling refrigerant circuit flowing through the cascade heat exchanger is equal to or higher than the outside air temperature. Good. The set temperature difference may be changed according to the outside air temperature. In the refrigerant circuit for air conditioning, a first expansion valve is provided between the heat source side heat exchanger and the use side heat exchanger, and between the heat source side heat exchanger and the first expansion valve. The refrigerant pipe is branched, and this branch pipe is connected to the cascade heat exchanger via a second expansion valve, and the second expansion valve has the temperature difference equal to the set temperature difference. The valve opening may be controlled.

  The one room may be a convenience store, and the temperature sensor may be provided in the vicinity of the entrance of the store.

  Further, the one room may be a convenience store, and the temperature sensor may be provided in the vicinity of the glass window of the store. The temperature sensor may be provided in a remote control device of the air conditioner.

  In the present invention, since the temperature sensor for air conditioning control is provided in the air conditioning load in one room or the portion where the fluctuation of the air conditioning load is the largest, the temperature in one room is quickly stabilized and the temperature in one room is stabilized. Stops the refrigerant flowing to the use side heat exchanger and flows the refrigerant from the air conditioning compressor to the cascade heat exchanger. As a result, when the refrigerant flow rate on the low-pressure side of the air conditioning system in the cascade heat exchanger increases, heat exchange with the high-pressure side refrigerant in the refrigeration system is promoted, and the load on the refrigeration side is stabilized accordingly. The operation can be stabilized and the energy consumption efficiency of the entire system can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a system configuration including a refrigerant circuit of an air conditioning refrigeration apparatus 1 according to an embodiment of the present invention. The air-conditioning refrigeration apparatus 1 is applied to a store such as a convenience store, for example. The air-conditioning in the store 2 and the inside of the refrigerator case 3 or the freezing case 4 as a storage facility (cooled facility) installed in the store 2 Cooling is realized. The refrigerated case 3 is a case in which the inside of the refrigerator is cooled to a refrigeration temperature (+ 3 ° C. to + 10 ° C.) and beverages, refrigerated foods, etc. are displayed, and the freezing case 4 has a freezing temperature (−30 ° C.). It is a case where frozen foods or frozen desserts are displayed.

  The air conditioning refrigeration apparatus 1 includes an air conditioning system unit 6 that performs air conditioning in the store 2 and a cooling system unit 8 that cools the refrigeration case 3 and the refrigeration case 4 in the store 2. The air conditioning system section 6 includes a plurality of indoor units 11 installed in the store 2, an outdoor unit 12 installed outside the store, and an air conditioning refrigerant circuit 7 provided between these units 11 and 12. And.

  The air conditioning refrigerant circuit 7 includes a use side heat exchanger 27 installed in the indoor unit 11, a heat source side heat exchanger 16 installed in the outdoor unit 12, and compressors 13 </ b> A and 13 </ b> B as the compression unit 13. A refrigeration cycle is performed.

  More specifically, the compressor 13A is an inverter compressor, and the compressor 13B is a constant speed control compressor. These compressors 13A and 13B are connected in parallel, the discharge sides of the compressors 13A and 13B are joined via check valves 5A and 5B, and are connected to one inlet of the four-way valve. One outlet of the four-way valve 14 is connected to the inlet of the heat source side heat exchanger 16. The heat source side heat exchanger 16 includes an inlet side 16A having a relatively small flow resistance composed of a large number of parallel pipes and an outlet side 16B in which these are aggregated into a small number of parallel pipes or a single pipe. Then, the outlet on the outlet side 16B of the heat source side heat exchanger 16 is divided through the expansion valve 17 and the expansion valve 18 and then connected to the inlet of each use side heat exchanger 27 of the indoor unit 11.

  The outlets of the respective use side heat exchangers 27 are joined together and then connected to the other inlet of the four-way valve 14 in the outdoor unit 12, and the other outlet of the four-way valve 14 is connected to the accumulator 23 via the check valve 22. Connected. The outlet of the accumulator 23 is connected to the suction side of the compressors 13A and 13B, so that the refrigerant discharged from the compression unit 13 is compressed via the heat source side heat exchanger 16 and the use side heat exchanger 27. Returned to unit 13.

  In this air conditioning refrigerant circuit 7, the refrigerant pipe between the expansion valve (first expansion valve) 17 and the expansion valve 18 is branched, and this branch pipe passes through the expansion valve (second expansion valve) 19. To the cascade heat exchanger 21. The cascade heat exchanger 21 is formed by laminating a plurality of heat transfer plates, alternately forming refrigerant passages 21A and 21B through which two kinds of refrigerants flow in each heat transfer plate tube, and connecting adjacent refrigerant passages 21A and 21B. A plate heat exchanger is used in which heat exchange is performed via a heat transfer plate while two kinds of refrigerants are circulating. In the cascade heat exchanger 21, the inlet of one refrigerant passage 21 </ b> A is connected to the expansion valve 19, and the outlet thereof is connected to the inlet of the accumulator 23. As a result, the refrigerant whose pressure has been reduced by the expansion valve 19 is supplied to the cascade heat exchanger 21 and then returned to the compression unit 13. That is, in the air conditioning refrigeration apparatus 1, a path α that passes through the use-side heat exchanger 27 and a path β that passes through the cascade heat exchanger 21 are formed as the refrigerant circulation paths.

  The outdoor air conditioning controller 26 is configured by a general-purpose microcomputer, and controls the equipment of the air conditioning system unit 6 on the outdoor unit 12 side based on the outside air temperature and the refrigerant pressure. The indoor side air conditioning controller 28 is composed of a general-purpose microcomputer, controls the equipment on the indoor unit 11 side based on a user instruction input via the remote controller 128, or responds to the user instruction to the outdoor air conditioning controller 26. Data communication is performed for information. The blower 24 is a blower that blows outside air to the heat source side heat exchanger 16, and the blower 15 is a blower that sends room air to the use side heat exchanger 27. On the other hand, the cooling system unit 8 includes a refrigeration case 3 and a refrigeration case 4 as storage facilities, and a cooling refrigerant circuit 9 provided between the outdoor unit 12.

  The cooling refrigerant circuit 9 includes a refrigeration evaporator 43 provided in the refrigeration case 3, a condenser (heat exchanger) 38 installed in the outdoor unit 12, a compressor 37 and a compressor 54 as compression units. Refrigerant circulation is performed.

  More specifically, the discharge side of the compressor 37 is connected to one inlet of the four-way valve 39 via the oil separator 31, and one outlet of the four-way valve 39 is connected to the inlet of the condenser 38. The condenser 38 includes an inlet side 38A having a relatively small flow resistance composed of a large number of parallel pipes and an outlet side 38B in which these are aggregated into a small number of parallel pipes or a single pipe. The outlet on the outlet side 38B of the condenser 38 is connected to the inlet of the receiver tank 36, and the outlet of the receiver tank 36 is connected to one inlet of the four-way valve 41. That is, the receiver tank 36 is connected to the refrigerant downstream side of the condenser 38.

  One outlet of the four-way valve 41 is connected to the inlet of the other refrigerant passage 21 </ b> B of the cascade heat exchanger 21. The outlet of the refrigerant passage 21 </ b> B of the cascade heat exchanger 21 is connected to the other inlet of the four-way valve 39, and the other outlet of the four-way valve 39 is connected to the other inlet of the four-way valve 41. The other outlet of the four-way valve 41 is branched into three, and the first branch pipe is connected to the inlet of one refrigeration evaporator 43 through the solenoid valves 47 and 46 and the expansion valve 44 in order, The second branch pipe is connected to the inlet of the other refrigeration evaporator 43 via the electromagnetic valve 46 and the expansion valve 44 in sequence, and the third branch pipe is connected to the freezing evaporator 49 via the electromagnetic valve 52 and the expansion valve 51. Connected to the entrance. An electromagnetic valve 53 is connected in parallel with the series circuit of the electromagnetic valve 52 and the expansion valve 51. The outlet of the refrigeration evaporator 49 is connected to the suction side of the compressor 54 via the check valve 30 and connected via the check valve 48 between the electromagnetic valves 46 and 47 on the refrigeration evaporator 43 side. Is done. The compressor 54 is a compressor having a smaller output than the compressor 37, and its discharge side is connected in series to the suction side of the compressor 37 via the oil separator 45.

  Further, the oil separator 45 and the compressor 37 are connected after the outlets of the refrigeration evaporators 43 are joined. The suction side of the compressor 37 is connected to the outlet of the oil separator 31 via a check valve 42.

  The outdoor side cooling controller 32 is composed of a general-purpose microcomputer, and controls the equipment of the cooling system unit 8 on the outdoor unit 12 side based on the outside air temperature and the refrigerant pressure. Moreover, the indoor side refrigeration controller 50 is comprised with a general purpose microcomputer, and controls the apparatus of the cooling system part 8 based on the internal temperature of the storage facility for refrigeration (refrigeration case 3). Moreover, the indoor side freezing controller 55 is comprised with a general purpose microcomputer, and controls the apparatus of the cooling system part 8 based on the internal temperature of the storage facility for freezing (refrigeration case 4). The blower 35 is a blower that blows outside air to the condenser 38, the blower 20 is a blower that sends the air in the refrigerator case 3 to the condenser 38, and the blower 25 is frozen to the freezing evaporator 49. This is a blower for sending the air in the case 4.

  The air conditioning refrigeration apparatus 1 includes a main controller 56. The main controller 56 is composed of a general-purpose microcomputer and performs data communication with the outdoor side air conditioning controller 26, the indoor side air conditioning controller 28, the outdoor side cooling controller 32, the indoor side refrigeration controller 50, and the indoor side refrigeration controller 55. The entire refrigeration apparatus 1 is controlled. In this air-conditioning refrigerating apparatus 1, different refrigerants are used in the air-conditioning refrigerant circuit 7 and the cooling refrigerant circuit 9, for example, R410A is used in the air-conditioning refrigerant circuit 7, and the cooling refrigerant circuit 9 R404A having a higher boiling point than R410A is used. Thus, since this air-conditioning refrigeration apparatus 1 can use the optimal refrigerant | coolant for each refrigerant circuit, respectively, it can raise the freedom degree of circuit design.

  FIG. 3 is a perspective view showing the inside of a convenience store.

  In this figure, a glass 64 is stretched on the front of the store so that the inside 2 of the store can be seen from outside, and an entrance 60 for entering and exiting the store is provided on the right side of the front of the store. Yes. When entering the store 2 from the entrance / exit 60, a book shelf 62 for placing books and the like along the glass 64 is arranged. A cash register 65 is provided on the right wall surface of the entrance 60, and a refrigerated case 3 (walk-in showcase) and a freezing case 4 are provided on the left wall surface of the entrance 60. That is, these cooling storage facilities 3 and 4 are disposed on the back side of the store away from the store entrance 60. Further, a refrigerated case 3 (open showcase) is disposed on the wall surface facing the entrance 60 side, and a display shelf 63 for displaying products is provided in the center of the store.

  An outdoor unit 12 is disposed outside the store, and the outdoor unit 12 is connected to a refrigeration case 3 and a refrigeration case 4 disposed in the store 2 via a cooling refrigerant circuit 9. The outdoor unit 12 is connected to the indoor units 11A and 11B disposed on the ceiling of the store 2 via the air conditioning refrigerant circuit 7. The indoor unit 11A is disposed near the cooling storage facilities 3 and 4, and the indoor unit 11B is disposed at a position away from the cooling storage facilities 3 and 4. The indoor units 11A and 11B have different air conditioning capabilities, and the indoor unit 11B close to the entrance / exit 60 has a larger air conditioning capability than the indoor units 11A close to the cooling storage facilities 3 and 4.

  In the above configuration, a wired remote controller (remote operation device) 128 is provided in the vicinity of the entrance / exit 60 in the store 2, and the remote control 128 includes a temperature sensor 129 for air conditioning control. In the vicinity of the entrance / exit 60 in the store 2, people frequently enter and exit. In the store 2, the air conditioning load is most likely to fluctuate and the vicinity of the entrance / exit 60 in the store 2 is glassed. It is easily exposed to direct sunlight, and in that sense, it is also a place where the air conditioning load increases.

  When the temperature sensor 129 is provided at this location, the air conditioning compressor 13 is operated and controlled according to the side where the air conditioning load is large, and the fluctuation of the air conditioning load is detected quickly, and the temperature in the store rises. Since the air-conditioning compressor 13 is controlled in accordance with the descent, the temperature in the store 2 quickly stabilizes.

  Next, the operation of the air conditioning refrigeration apparatus 1 will be described.

  In the air conditioning refrigeration apparatus 1, the air conditioning system unit 6 includes a set temperature instructed by the outdoor air conditioning controller 26 and the indoor air conditioning controller 28 via the remote controller 128, and a temperature sensor 129 that is also attached to the remote controller 128. The cooling operation or the heating operation is performed according to the deviation from the temperature in the store 2 (room temperature TA) detected by the above, and the room temperature is air-conditioned to the set temperature. In addition, the cooling system unit 8 sets the internal temperature of the refrigeration case 3 to a preset refrigeration temperature under the control of the outdoor side cooling controller 32, the indoor side refrigeration controller 50, and the indoor side refrigeration controller 55, and the refrigeration case The inside temperature of 4 is set to a preset freezing temperature.

More specifically, in this air-conditioning refrigeration apparatus 1, the main controller 56 performs data communication with each of the controllers 26, 28, 32, 50, 55, so that data relating to the current operating state of the air-conditioning system unit 6 and the cooling system unit 8. , And based on the received data, an optimal operation pattern at that time, which will be described later, is determined, and data relating to the optimal operation pattern and operation data of each device are transmitted to the controllers 26, 28, 32, 50, 55. . Each controller 26, 28, 32, 50, 55 executes a control operation to be described later based on the data received from the main controller 56.
(1) Cooling operation of air conditioning system section First, when the indoor side air conditioning controller 28 determines that the cooling operation of the air conditioning system section 6 is optimal, the indoor side air conditioning controller 28 is directed to the outdoor air conditioning controller 26 and the main controller 56 to perform the cooling operation. The main controller 56 that has received the data transmits the data to the outdoor side cooling controller 32, the indoor side refrigeration controller 50, and the indoor side refrigeration controller 55.

  As shown in FIG. 1, the outdoor air-conditioning controller 26 uses one inlet (a connection port with the oil separator 10) of the four-way valve 14 as one outlet (a connection port with the heat source side heat exchanger 16) based on the received data. And the other inlet (connection port with the use side heat exchanger 27) is communicated with the other outlet (connection port with the accumulator 23). Further, the expansion valve 17 is fully opened, and the compressors 13A and 13B are operated. The outdoor air-conditioning controller 26 controls the capacity of the compressor 13A by inverter-controlling the operation frequency.

  When the compressors 13A and 13B are operated, the high-temperature and high-pressure gas refrigerant discharged from the discharge sides of the compressors 13A and 13B passes through the four-way valve 14 from the oil separator 10 to the inlet side 16A of the heat source side heat exchanger 16. enter. Outside air is ventilated by the air blower 24 to the heat source side heat exchanger 16, and the refrigerant dissipates heat here to be condensed and liquefied. That is, in this case, the heat source side heat exchanger 16 functions as a condenser. The liquid refrigerant is branched after passing through the expansion valve 17 via the heat source side heat exchanger 16. One of the branches reaches the expansion valve 18, where it is throttled to a low pressure (decompression), and then branches into each use side heat exchanger 27 and flows there. Indoor air (air in the store) is ventilated by the blower 15 to the use side heat exchanger 27, and the indoor air is cooled by an endothermic action due to evaporation of the refrigerant.

  Thereby, the room (inside the store) is cooled. After the low-temperature gas refrigerant that has exited from the use side heat exchanger 27 is merged, circulation is repeated through the four-way valve 14, the check valve 22, and the accumulator 23, and then supplied to the suction sides of the compressors 13 </ b> A and 13 </ b> B.

  Further, the other refrigerant branched after passing through the expansion valve 17 reaches the expansion valve 19 where it is throttled to a low pressure (decompression), and then flows into the refrigerant passage 21A of the cascade heat exchanger 21 where it evaporates. . The cascade heat exchanger 21 is cooled by the endothermic action due to the evaporation of the refrigerant in the air-conditioning refrigerant circuit 7 and becomes a low temperature. The low-temperature gas refrigerant exiting the cascade heat exchanger 21 repeats circulation supplied to the suction sides of the compressors 13A and 13B via the accumulator 23.

  Based on the air temperature in the store 2 detected via the temperature sensor 129, the indoor side air conditioning controller 28 sets the indoor side (inside the store) to the use side heat exchanger 27 so that the temperature in the room (in the store) is set to a preset temperature. The blower 15 which ventilates is controlled. Information on the indoor air conditioning controller 28 is transmitted to the outdoor air conditioning controller 26, and the outdoor air conditioning controller 26 controls the operation of the compressors 13A and 13B based on this information.

  The outdoor air-conditioning controller 26 detects the refrigerant temperature at the entrance / exit of the use side heat exchanger 27 or the temperature of the use side heat exchanger 27 detected via a temperature sensor (not shown) and the entrance / exit of the cascade heat exchanger 21. Based on the refrigerant temperature or the temperature of the cascade heat exchanger 21, the valve openings of the expansion valves 18 and 19 are adjusted so as to obtain an appropriate degree of superheat.

  On the other hand, the outdoor side cooling controller 32 supplies one inlet (oil) of the four-way valve 39 of the cooling refrigerant circuit 9 of the cooling system unit 8 in order to supply the high-temperature and high-pressure gas refrigerant discharged from the compressor 37 to the condenser 38. The connection port with the separator 31 is connected to one outlet (connection port with the condenser 38), and the other inlet (connection port with the cascade heat exchanger 21) is connected to the other outlet (connection port with the four-way valve 41). ).

  In addition, the outdoor side cooling controller 32 uses one inlet (a connection port with the four-way valve 39) of the four-way valve 41 as one outlet (refrigeration) in order to supply the gas refrigerant that has passed through the condenser 38 to the cascade heat exchanger 21. Communication with the evaporator 43 and the refrigeration evaporator 49 (connection ports with the electromagnetic valves 46, 47, 52), and the other inlet (connection port with the receiver tank 36) is connected with the other outlet (cascade heat exchanger 21). Communication port). Then, the compressors 37 and 54 are operated.

  As a result, the high-temperature and high-pressure gas refrigerant discharged from the compressor 37 enters the inlet side 38 </ b> A of the condenser 38 through the four-way valve 39 after the oil is separated by the oil separator 31. Outside air is passed through the condenser 38 by the blower 35, and the refrigerant flowing into the condenser 38 dissipates heat and condenses. The refrigerant discharged from the condenser 38 enters the receiver tank 36 and is temporarily stored therein to separate the gas / liquid. The separated liquid refrigerant exits from the receiver tank 36 and passes through the four-way valve 41, and then enters the refrigerant passage 21B of the cascade heat exchanger 21. The refrigerant in the cooling refrigerant circuit 9 supplied to the cascade heat exchanger 21 is cooled by the cascade heat exchanger 21 that is at a low temperature due to evaporation of the refrigerant in the air conditioning refrigerant circuit 7 as described above, and further subcooled. The Since the receiver tank 36 is disposed immediately after the condenser 38 as described above, heat loss during supercooling can be eliminated and the amount of refrigerant can be adjusted.

  The refrigerant supercooled in the cascade heat exchanger 21 is branched after sequentially passing through the four-way valves 39, 41, one is further branched, and the other is sequentially passed through the electromagnetic valves 47, 46, and then the expansion valve 44. After being throttled by (reduced pressure), it is supplied to one refrigeration evaporator 43, where it evaporates and the other branched through the electromagnetic valve 46 to the expansion valve 44, where it is throttled (reduced pressure), It flows into the other refrigeration evaporator 43 and evaporates there. In each refrigeration evaporator 43, the air in the refrigerator case 3 is ventilated and circulated by the blower 20, and the air in each refrigerator is cooled by the endothermic action due to the evaporation of the refrigerant. Thereby, the inside cooling of the refrigeration case 3 is performed. These low-temperature gas refrigerants exiting the refrigeration evaporator 43 are merged and then reach the outlet side of the oil separator 45 of the compressor 54.

  The other refrigerant that is subcooled and branched in the cascade heat exchanger 21 passes through the electromagnetic valve 52 to reach the expansion valve 51, where it is throttled (decompression) and then supplied to the refrigeration evaporator 49. Where it evaporates. The refrigeration evaporator 49 is circulated and circulated with the air in the refrigeration case 4 by the blower 25, and the refrigeration evaporator 49 is cooled by the endothermic effect of the evaporation of the refrigerant. Thereby, the inside cooling of the freezing case 4 is performed.

  The low-temperature gas refrigerant exiting the freezing evaporator 49 reaches the compressor 54 via the check valve 30, where it is compressed and pressurized to the pressure on the outlet side of the refrigerating evaporator 43 (low pressure side pressure of the refrigerating system). After that, the oil is discharged from the compressor 54 and separated by the oil separator 45, and then merged with the refrigerant from the refrigeration evaporator 43. The merged refrigerant repeats circulation that is sucked into the suction side of the compressor 37.

  The indoor side refrigeration controller 50 detects the internal temperature of the refrigeration case 3 detected through a temperature sensor (not shown), the cold air temperature discharged through the refrigeration evaporator 43 or the cold air temperature sucked into the refrigeration evaporator 43, and the refrigeration. The opening degree of each expansion valve 44 is controlled based on the refrigerant temperature on the outlet side of the evaporator 43 for cooling or the temperature of the evaporator 43 for refrigeration. Thereby, it is set as the appropriate superheat degree (constant superheat degree), maintaining the inside of the refrigerator | coolant case 3 cooling at the refrigeration temperature mentioned above. Further, the indoor side refrigeration controller 55 is configured such that the inside temperature of the refrigeration case 4, the temperature of the cold discharged from the refrigeration evaporator 49, or the temperature of the intake chilled air to the refrigeration evaporator 49 and the refrigerant on the outlet side of the refrigeration evaporator 49 The valve opening degree of the expansion valve 51 is controlled based on the temperature or the temperature of the freezing evaporator 49. As a result, while maintaining the inside of the freezing case 4 to be cooled to the above-described freezing temperature, an appropriate degree of superheat (constant superheat) is obtained.

  Further, the outdoor cooling controller 32, when any one of the expansion valves 44, 51 is open, is based on the suction side pressure of the compressor 37 (low pressure of the cooling refrigerant circuit 9). And the operation of the compressor 37 is stopped when all the expansion valves 44 and 51 are fully closed.

  According to this, during the cooling operation, the low-pressure side refrigerant flowing through the air-conditioning refrigerant circuit 7 is supplied to the cascade heat exchanger 21, and the high-pressure side refrigerant flowing through the cooling refrigerant circuit 9 is supercooled. The cooling capacity and operation efficiency of the part 8 can be improved.

Note that the pressure of the refrigerant discharged from the refrigeration evaporator 49 of the cooling refrigerant circuit 9 is lower than that of the refrigerant discharged from the refrigeration evaporator 43 because the evaporation temperature thereof is lower, but the refrigerant discharged from the refrigeration evaporator 43 is reduced. Since it is compressed by the compressor 54 before merging with the refrigerant, the compressor 54 compresses the compressor while cooling each case to an appropriate temperature even when controlling to different chamber temperatures such as the refrigeration case 3 and the refrigeration case 4. The pressure of the refrigerant sucked into 37 can be made uniform, and the operation can be performed without any trouble.
(2) Heating operation of the air conditioning system unit Next, the heating operation of the air conditioning system unit will be described with reference to FIG.

  First, when the indoor side air conditioning controller 28 determines that the heating operation of the air conditioning system unit 6 is optimal, the indoor side air conditioning controller 28 transmits predetermined data to the outdoor air conditioning controller 26 and the main controller 56 to perform the heating operation. The main controller 56 that has received the data transmits these data to the outdoor side cooling controller 32, the indoor side refrigeration controller 50, and the indoor side refrigeration controller 55.

  Based on the received data, the outdoor air-conditioning controller 26 connects one inlet (a connection port with the oil separator 10) of the four-way valve 14 to one outlet (the accumulator 23) in order to reverse the refrigerant flow to that during the cooling operation. The other inlet (connection port with the use side heat exchanger 27) is communicated with the other outlet (connection port with the heat source side heat exchanger 16). Further, the expansion valve 17 is fully closed and the expansion valve 18 is fully opened, and the compressors 13A and 13B are operated. When the compressors 13A and 13B are operated, the high-temperature and high-pressure gas refrigerant discharged from the discharge sides of the compressors 13A and 13B is supplied to the use-side heat exchanger 27 via the four-way valve 14.

  The use side heat exchanger 27 is ventilated with room air by the blower 15, and the refrigerant dissipates heat here and heats the room air while condensing. Thereby, the room (inside the store) is heated. The refrigerant liquefied by the use side heat exchanger 27 is reduced in pressure through the expansion valve 18 and the expansion valve 19 in order (decompression), then flows into the refrigerant passage 21A of the cascade heat exchanger 21 and evaporates there. After the heat is absorbed, the circulation supplied to the suction side of the compressors 13A and 13B through the accumulator 23 is repeated. The outdoor side air conditioning controller 26 adjusts the valve opening degree of the expansion valves 18 and 19 so as to achieve an appropriate degree of superheat based on the refrigerant temperature at the entrance and exit of the cascade heat exchanger 21 or the temperature of the cascade heat exchanger 21. .

  Moreover, the indoor side air conditioning controller 28 uses the use side heat exchanger 27 so that the temperature of the room (inside the store) is set to a preset temperature based on the temperature of the use side heat exchanger 27 and the air temperature sucked therein. The blower 15 that ventilates the air is controlled.

  On the other hand, the outdoor side cooling controller 32 uses one inlet (a connection port with the oil separator 31) of the four-way valve 39 of the cooling refrigerant circuit 9 of the cooling system unit 8 as one outlet (a connection port with the four-way valve 41). The other inlet (connection port with the cascade heat exchanger 21) is communicated with the other outlet (connection port with the condenser 38). In addition, the outdoor side cooling controller 32 uses one inlet (a connection port with the four-way valve 39) of the four-way valve 41 as one outlet (a refrigeration evaporator 43 and a freezing evaporator 49 (solenoid valves 46, 47, 52)). And the other inlet (connection port with the receiver tank 36) is communicated with the other outlet (connection port with the cascade heat exchanger 21). Then, the compressors 37 and 54 are operated.

  Thus, the high-temperature and high-pressure gas refrigerant discharged from the compressor 37 is supplied to the refrigerant passage 21B of the cascade heat exchanger 21 via the four-way valves 39 and 41. That is, the high-temperature and high-pressure gas refrigerant discharged from the compressor 37 is supplied to the cascade heat exchanger 21 after passing through the condenser 38 in the cooling operation, whereas the cascade heat exchange is performed before going to the condenser 38. Is supplied to the vessel 21. The refrigerant in the cooling refrigerant circuit 9 supplied to the cascade heat exchanger 21 is cooled by the cascade heat exchanger 21 that is at a low temperature due to evaporation of the refrigerant in the air conditioning refrigerant circuit 7 as described above, and further subcooled. The In other words, the refrigerant in the air conditioning refrigerant circuit 7 can pump up heat from the refrigerant in the cooling refrigerant circuit 9.

  The refrigerant that has passed through the refrigerant passage 21 </ b> B of the cascade heat exchanger 21 enters the inlet side 38 </ b> A of the condenser 38 through the four-way valve 39. Outside air is passed through the condenser 38 by the blower 35, and the refrigerant flowing into the condenser 38 dissipates heat and condenses.

  The refrigerant discharged from the condenser 38 enters the receiver tank 36 and is temporarily stored therein to separate the gas / liquid. The separated liquid refrigerant is branched after leaving the receiver tank 36 and passing through the four-way valve 41, one branching further, one passing through the electromagnetic valves 47 and 46 sequentially, and being throttled by the expansion valve 44 ( Pressure reduction) is supplied to one refrigeration evaporator 43, where it evaporates, and the other branched through the electromagnetic valve 46 reaches the expansion valve 44, where it is throttled (decompression) and the other refrigeration evaporator. 43 where it evaporates. In each refrigeration evaporator 43, the air in the refrigerator case 3 is ventilated and circulated by the blower 20, and the air in each refrigerator is cooled by the endothermic action due to the evaporation of the refrigerant.

  By the above operation, even during the heating operation of the air conditioning refrigerant circuit 7, the low-pressure side refrigerant flowing through the air-conditioning refrigerant circuit 7 is supplied to the cascade heat exchanger 21, and the high-pressure side refrigerant flowing through the cooling refrigerant circuit 9 is excessively passed. By cooling, the cooling capacity of the refrigeration evaporators 43 and 44 of the refrigeration case 3 and the refrigeration case 4 and the operation efficiency of the cooling system unit 8 can be improved.

  Furthermore, during the heating operation, the refrigerant in the air conditioning refrigerant circuit 7 pumps up heat from the refrigerant in the cooling refrigerant circuit 9 in the cascade heat exchanger 21, so that the heating capacity of the air conditioning system unit 6 can be improved. The efficiency of the entire air conditioning refrigeration apparatus 1 that performs indoor air conditioning and cooling of the refrigerator case 3 and the refrigeration case 4 can be improved to save energy.

Particularly in this case, the refrigerant on the high-pressure side of the cooling refrigerant circuit 9 is supplied to the cascade heat exchanger 21 before the condenser 38, so that exhaust heat recovery from this refrigerant is efficiently performed, and the air conditioning refrigerant circuit 7 The heating capacity can be further improved.
(3) Operation control at the time of thermo-off at the time of cooling operation of the air conditioning system section By the way, in a general air conditioner (corresponding to the air conditioning system section 6), the room temperature is substantially the same as or lower than the set temperature during the cooling operation. In the state, that is, when the cooling thermo-off is being performed, the operation of the compression unit (corresponding to the compression unit 13) is stopped. On the other hand, the air conditioning refrigeration apparatus 1 of the present embodiment operates the compression unit 13 of the air conditioning system unit 6 to operate the cooling system unit 8 when the cooling system unit 8 is operating even when the cooling thermostat is off. Supercooling of the flowing refrigerant is performed.

  Hereinafter, the operation when the cooling thermostat is off will be described.

  5 and 6 are flowcharts showing the operation during the cooling thermo-off.

  First, the main controller 56 determines whether or not the compression unit (the compressors 37 and 54) of the cooling system unit 8 is ON (operating) based on the data received from the outdoor cooling controller 32 (step S1). When the compression unit is OFF (during operation stop), the valve fixing pulse Pv of the expansion valve 19 is set to zero so that the valve opening is zero (fully closed), and the rotation of the compression unit 13 of the air conditioning system unit 6 is rotated. The frequency Fr is set to zero and the compression unit 13 is stopped (step S10).

  On the other hand, when the compression unit of the cooling system unit 8 is ON, the main controller 56 determines whether or not the cooling system unit 8 is defrosting (step S2). On the other hand, if it is not defrosting, it is determined whether or not the compression unit 13 is forcibly stopped based on the data received from the outdoor air conditioning controller 26 (step S3). Here, when the compression unit 13 is forcibly stopped, after the compression unit 13 is completely stopped, the compression unit 13 is held in a stopped state for a predetermined forced stop period (for example, 3 minutes) to protect the compression unit 13. It is a state to do.

  When the compression unit 13 is not forcibly stopped, the outdoor air-conditioning controller 26 sets the valve fixing pulse Pv of the expansion valve 19 to a predetermined initial pulse according to an instruction from the main controller 56, and opens the valve opening of the expansion valve 19. Is controlled from the fully closed state to the initial opening degree (step S4). That is, the expansion valve 19 is opened and fixedly controlled to the initial opening degree when the condition that the compression unit of the cooling system unit 8 is not operating, defrosting, and the compression unit 13 of the air conditioning system unit 6 is not forcibly stopped. .

  Next, the outdoor air conditioning controller 26 sets the target rotation frequency Fr of the compression unit 13 to a predetermined initial target frequency (step S5). In the present embodiment, the setting of the target rotation frequency Fr of the compression unit 13 means the setting of the target rotation frequency of the compressor 13A, and when the compressor 13A is rotated, the compressor 13B is set to a preset steady state. The rotation frequency for rotation is controlled.

  By the operation of the compression unit 13, the refrigerant circulates through the air conditioning refrigerant circuit 7, and the refrigerant whose pressure is reduced by the expansion valve 19 is supplied to the refrigerant passage 21 </ b> A of the cascade heat exchanger 21. Thereby, the cascade heat exchanger 21 is cooled by the endothermic action due to the evaporation of the refrigerant, and the high-pressure side refrigerant of the cooling refrigerant circuit 9 flowing through the refrigerant passage 21B of the cascade heat exchanger 21 can be supercooled.

  Next, the outdoor air conditioning controller 26 sets the temperature difference ΔTE on the basis of the temperature difference ΔTE between the refrigerant outlet temperature TE2 and the inlet temperature TE1 on the air conditioning system unit 6 side in the cascade heat exchanger 21. The SH control (step S6) for setting the correction pulse Δa of the valve fixing pulse Pv for setting the temperature difference SH, the discharge temperature of the compression unit 13 of the air conditioning system unit 6 (discharge temperature TD1 of the compressor 13A, the compressor 13B) Based on the discharge temperature TD2), TD control (step S7) for setting the correction pulse Δb of the valve fixing pulse Pv for protecting the compression unit 13 is performed. The correction pulse Δb is set when the discharge temperature of the compression unit 13 becomes equal to or higher than a predetermined temperature.

  Further, the outdoor air conditioning controller 26 sets the temperature difference ΔSC to a predetermined target temperature based on the temperature difference ΔSC between the refrigerant inlet temperature TC1 and the outlet temperature TC2 on the cooling system unit 8 side in the cascade heat exchanger 21. SC control is performed to set the correction rotation frequency Δc of the compression unit 13 so as to set the difference (set temperature difference) SC and the outlet temperature TC2 to be equal to or higher than the outside air temperature (step S8). Here, the refrigerant outlet temperature TC2 is set to be equal to or higher than the outside air temperature. Usually, a heat insulating material is wound around the refrigerant pipe (indicated by γ in FIG. 1) connecting the cascade heat exchanger 21 and the four-way valve 39. This is because if the refrigerant passing through the refrigerant pipe is lower than the outside air temperature, the refrigerant is warmed and flash gas is generated, resulting in heat loss. However, when the heat insulating material is wound around the refrigerant pipe γ, it is only necessary to set the temperature difference ΔSC to the predetermined target temperature difference SC at the correction frequency ΔFr in step S8, and the refrigerant outlet temperature TC2 is set. Conditions that make the temperature higher than the outside temperature may be excluded.

  The target temperature difference SC is changed according to the outside air temperature. For example, if the outside air temperature is 30 ° C. or higher, the value SC1 is set. If the outside air temperature is 20 ° C. or higher and lower than 30 ° C., the value SC2 is set. If the outside air temperature is lower than 20 ° C., the value SC3 is changed. Here, the target temperature difference SC is set such that the value SC1 <value SC2 <value SC3 so as to be set to a larger value as the outside air temperature is lower. The outdoor air conditioning controller 26 adds the correction pulses Δa and Δb obtained in steps S6 and S7 to the current valve fixing pulse Pv (Pv_old), and calculates the value of the valve fixing pulse Pv to be controlled next. (Step S9), the valve fixing pulse Pv of the expansion valve 19 is set within the range of the upper limit pulse (Pv_max) and the lower limit pulse (Pv_min) of the expansion valve 19, and the valve opening degree is controlled (Step S10).

  Next, the outdoor air conditioning controller 26 adds the corrected rotation frequency Δc obtained in step S8 to the current target rotation frequency Fr (Fr_old) to calculate the next target rotation frequency Fr of the compression unit 13 (step). S11). If the calculated target rotation frequency Fr is within the range between the upper limit frequency (Fr_max) and the lower limit frequency (Fr_min), the rotation speed of the compression unit 13 is controlled to the target rotation frequency Fr (step S12).

  Here, the range of the upper limit frequency (Fr_max) and the lower limit frequency (Fr_min) is set to an upper limit value and a lower limit value of a frequency range in which the efficiency of the compression unit 13 (compressor 13A) is good (efficiency greater than or equal to a predetermined value). The Thereby, it is possible to control the compression unit 13 to an efficient rotation frequency.

  However, if the refrigerant in the air conditioning system 6 is excessively cooled even if the rotation frequency of the compression unit 13 is lowered to the lower limit frequency, the rotation of the compression unit 13 is stopped and the operation of the air conditioning system 6 is stopped. Specifically, after the processing in step S12, the outdoor air conditioning controller 26 determines whether or not the target rotation frequency Fr substantially matches the lower limit frequency (step S13). The process proceeds to S1. On the other hand, when the target rotation frequency Fr substantially coincides with the lower limit frequency, the outdoor air conditioning controller 26 determines that the temperature difference ΔSC at the refrigerant inlet / outlet in the cascade heat exchanger 21 is a predetermined temperature than the target temperature difference SC. It is determined whether or not the temperature is higher than (eg, 10 ° C.) (step S14). If the temperature is higher than the temperature, the process proceeds to step S15.

  As a result, the rotation of the compression unit 13 is stopped, the opening degree of the expansion valve 19 is set to zero, and the rotation of the air conditioning system unit 6 is stopped. In addition, even if it raises the rotation frequency of the compression unit 13 to an upper limit frequency, when the supercooling of the refrigerant | coolant of the air-conditioning system part 6 cannot be taken, rotation of the compression unit 13 is continued with the upper limit frequency. And the outdoor air-conditioning controller 26 transfers to the process of step S1 even if it complete | finishes any said process, and repeats the process of step S1-S13 or the process of step S1-S15 during a cooling thermo-off. According to this, during the cooling thermo-off, the rotation control of the compression unit 13 and the control of the valve opening degree of the expansion valve 19 are executed.

  The above operation is not limited to when the cooling thermo-off is performed, but also when the operation of the air-conditioning system unit 6 is stopped by a stop instruction from a remote controller or the like after the cooling operation, that is, when the air-conditioning operation is stopped after the cooling operation. Is done.

  Thus, this air-conditioning refrigeration apparatus 1 is the compression unit of the air-conditioning system unit 6 when the compression unit (compressors 37, 54) of the cooling system unit 8 is operating when the compression unit 13 of the air-conditioning system unit 6 is stopped. 13 is operated and the low-pressure side refrigerant flowing through the air-conditioning refrigerant circuit 7 is supplied to the cascade heat exchanger 21, so that the high-pressure side refrigerant flowing through the cooling refrigerant circuit 9 is always supercooled even during the cooling thermo-off. can do. As a result, it is possible to avoid a situation in which the cooling capacity of the cooling system unit 8 is lowered during the cooling thermo-off, and it is possible to maintain the cooling capacity and the operation efficiency of the cooling system unit 8 in a high state.

  In particular, during the cooling thermo-off, the compression unit 13 of the air conditioning system unit 6 is controlled within an efficient rotation frequency range, so that the energy consumption efficiency can be further improved. Further, by setting the target temperature difference SC of the temperature difference ΔSC between the refrigerant inlet temperature TC1 and the outlet temperature TC2 on the cooling system unit 8 side in the cascade heat exchanger 21 to a larger value as the outside air temperature is lower, the outside air temperature is increased. Accordingly, the degree of supercooling of the refrigerant in the cooling system unit 8 can be adjusted appropriately. In the above-described embodiment, the expansion valve 19 may use various electric valves as long as the supply / stop of the refrigerant can be switched.

  In the operation control of (1) to (3), especially during the cooling thermo-off, the compression unit 13 of the air-conditioning system unit 6 is controlled within an efficient rotational frequency range, so that the energy consumption efficiency can be further improved. . For that purpose, it is important to quickly stabilize the indoor temperature in the store 2 and then promote heat exchange in the cascade heat exchanger 21. By controlling in this way, the energy consumption efficiency of the entire system can be improved without sacrificing air conditioning.

  In the present embodiment, referring to FIG. 3, a remote controller 128 is provided in a portion (near the entrance / exit 60) where the fluctuation of the air conditioning load in the store 2 is the largest, and a temperature sensor 129 for air conditioning control is provided in the remote controller 128. As shown in FIG. 4, when remote control sensor control is started (S21), if there is a change in the air-conditioning load due to the entry or exit of a person (S22), the change is quickly detected (S23), so-called in-store temperature. The air-conditioning side compressor 13 is controlled in accordance with the rise and fall of (S24). Alternatively, if the vicinity of the entrance / exit 60 in the store 2 is glazed, it is easy to receive direct sunlight and the like, and in that sense, it is also a place where the air conditioning load becomes large (S25). The operation of the air conditioning compressor 13 is controlled in accordance with the rise and fall (S26).

  In any of the cases described above, the temperature in the store 2 quickly stabilizes in any case (S27), and since this quickly stabilizes, the amount of refrigerant used for air conditioning can be suppressed early. It becomes like this. Therefore, it is possible to control the valve opening of the expansion valve 18 of FIG. 1 and the expansion valve 18 can be fully closed depending on the situation. If it becomes like this, it will become possible to increase the refrigerant | coolant flow volume of the low voltage | pressure side of the air conditioning system part in the cascade heat exchanger 21, and if this increases, the refrigerant | coolant of the low voltage | pressure side of an air conditioning system part and the high pressure | voltage of a freezing system part will be increased. Heat exchange with the refrigerant on the side is promoted, and accordingly, the load on the refrigeration side is stabilized earlier (S28), and the operation is stabilized (S29). Usually, when the energy consumption efficiency of the air conditioning system unit and the energy consumption efficiency of the refrigeration system unit are compared, the energy consumption efficiency of the air conditioning system unit is excellent, and therefore the heat exchange in the cascade heat exchanger 21 is further promoted. In this case, the energy consumption efficiency of the entire system can be improved by that amount (S30).

  In the present embodiment, the temperature in the store 2 is quickly stabilized, and more heat exchange in the cascade heat exchanger 21 is promoted. Therefore, the energy consumption efficiency of the entire system is improved without sacrificing air conditioning. Can be made.

  Although one embodiment of the present invention has been described above, the present invention is not limited to this. For example, in the above-described embodiment, the case where the present invention is applied to an air-conditioning refrigeration apparatus applied to a store such as a convenience store has been described. However, air conditioning and cooling of equipment to be cooled other than the refrigeration case 3 and the refrigeration case 4 It can apply widely to the air-conditioning refrigeration apparatus to perform. Furthermore, the piping configuration shown in the above embodiment is not limited thereto, and can be appropriately changed without departing from the gist of the present invention.

It is a figure which shows the system configuration | structure containing the refrigerant circuit of the air-conditioning refrigerating apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the heating operation of the air-conditioning system part of the air-conditioning refrigerating apparatus which concerns on embodiment of this invention. It is a perspective view which shows the store arrangement | positioning structure of a convenience store. It is a flowchart which shows remote control sensor control. It is a flowchart which shows the operation | movement during air_conditioning | cooling thermo-off. It is a flowchart which shows the operation | movement during air_conditioning | cooling thermo-off.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air-conditioning freezer 3 Refrigerating case 4 Refrigeration case 6 Air-conditioning system part 7 Air-conditioning system part 7 Air-conditioning refrigerant circuit 8 Cooling system part 9 Cooling refrigerant circuit 10 Oil separator 11 Indoor unit 12 Outdoor unit 13 Compression unit 13A, 13B, 37, 54 Compressor 17 , 18, 19 Expansion valve 21 Cascade heat exchanger 60 Entrance / exit 128 Remote controller 129 Temperature sensor

Claims (6)

  An air conditioning system unit that includes an air conditioning compressor, a heat source side heat exchanger, and a usage side heat exchanger and performs air conditioning in one room by the usage side heat exchanger, and includes a cooling compressor, a condenser, and an evaporator Heat between the refrigeration system section that cools the inside of the cooling storage facility disposed in the one room by the evaporator, the refrigerant on the low-pressure side of the air-conditioning system section, and the refrigerant on the high-pressure side of the refrigeration system section. A cascade heat exchanger for exchanging, and an air conditioning load in the one room or a portion where the fluctuation of the air conditioning load is large is provided with a temperature sensor for air conditioning control, and according to the detected value of the temperature sensor, When the air conditioning system unit has reached a cooling thermo-off, the air conditioning system further includes control means for controlling the refrigerant flow on the low-pressure side of the air conditioning system unit that continues to operate the air conditioning compressor and flows to the cascade heat exchanger. Air-conditioning refrigeration Location.   The air-conditioning refrigeration apparatus according to claim 1, wherein when the air-conditioning compressor is operated during the cooling thermo-off, the rotation frequency is controlled within a predetermined frequency range. The air-conditioning system section is configured such that the air-conditioning compressor is configured to set a temperature difference between an inlet temperature and an outlet temperature of a refrigerant on a high-pressure side of the cooling refrigerant circuit flowing through the cascade heat exchanger as a preset temperature difference. The target rotation frequency of
When this target rotational frequency is within the predetermined frequency range, the rotational frequency of the air conditioning compressor is controlled to the target rotational frequency, while the rotational frequency substantially matches the lower limit frequency of the predetermined frequency. When the temperature difference is equal to or higher than the preset temperature difference and the rotation frequency is substantially equal to the upper limit frequency of the predetermined frequency, and the temperature difference is equal to or less than the preset temperature difference from the preset temperature difference The air-conditioning refrigeration apparatus according to claim 2, wherein the operation of the air-conditioning compressor is stopped.   The air conditioning refrigeration apparatus according to any one of claims 1 to 3, wherein the one room is a convenience store, and the temperature sensor is provided in the vicinity of an entrance of the store.   The air-conditioning refrigeration apparatus according to any one of claims 1 to 4, wherein the one room is a convenience store, and the temperature sensor is provided in the vicinity of a glass window of the store.   The air conditioning refrigeration apparatus according to any one of claims 1 to 5, wherein the temperature sensor is provided in a remote control device of an air conditioner.

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