JP2010196915A - Refrigerating cycle system and method of controlling the refrigerating cycle system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating cycle system including a plurality of evaporators and efficiently performing heating and cooling in parallel, and a method of controlling the refrigerating system. <P>SOLUTION: When heating and cooling are performed in parallel in a host device M1 and remote devices M2, M3, a refrigerator condensed by a condenser 22 and a refrigerant condensed by the evaporator 30B or 30C performing heating are sent to the evaporator 30A and the evaporator 30C or 30B for cooling. Since the condensed refrigerant is used by the evaporator 30B or 30C performing heating and cooling is performed by the other evaporators 30A and 30C or 30B, capacity on the cooling side is enhanced and use efficiency of thermal energy is also enhanced. Electronic expansion valves 27A, 27B, 27C which are not mechanical types are provided upstream of the evaporators 30A, 30B, 30C. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a refrigeration cycle system applied to a refrigeration vehicle, a refrigeration vehicle, and the like, and a control method for the refrigeration cycle system.

In a refrigerator car, a refrigerator car, etc., the inside of a luggage storage is maintained at a predetermined temperature by a refrigeration cycle system. As is well known, the refrigeration cycle system is basically a gas refrigerant compressed at a high temperature and high pressure by a compressor, cooled by a condenser to form a liquid refrigerant, and the liquid refrigerant is evaporated by an evaporator disposed in a luggage storage. Therefore, the temperature is adjusted by exchanging heat with the atmosphere in the cabinet.
In recent years, a refrigeration cycle unit for vehicles equipped with both a freezer compartment and a refrigerator compartment, a refrigerator compartment and a greenhouse, etc. by dividing one luggage compartment into a plurality of compartments and making the temperature of each compartment different. Provided and contributes to efficient transportation (see, for example, Patent Documents 1 and 2). Thus, when making the temperature of several cargo compartments differ, an evaporator is each arrange | positioned at each cargo compartment. On the other hand, a compressor, a condenser, and the like are commonly used in a plurality of evaporators. That is, a single system is configured to include a plurality of evaporators.

FIG. 5 is a diagram showing a schematic configuration of a conventional refrigeration cycle unit 2 provided with a plurality of evaporators 1A and 1B, and a host machine provided with a compressor 3, a condenser 4, and an evaporator 1A in a first cargo compartment A. M1 is provided, and a remote machine M2 having an evaporator 1B is arranged in the second luggage compartment B.
A liquid refrigerant transport pipe 6 that transports the liquid refrigerant sent out from the capacitor 4 branches at the host machine M1, and is connected to the evaporators 1A and 1B. Further, a suction pipe 7 is connected to the compressor 3, and the suction pipe 7 is branched by the host machine M1 and connected to the evaporators 1A and 1B, and sucks the refrigerant after heat exchange from the evaporators 1A and 1B. . Connected to the compressor 3 is a hot gas transfer pipe 8 that sends out a gas refrigerant compressed to a high temperature and high pressure (hereinafter referred to as hot gas as appropriate). The hot gas transfer pipe 8 is connected to the capacitor 4. Has been. The hot gas transfer pipe 8 branches on the upstream side of the condenser 4 and merges with the liquid refrigerant transfer pipe 6 on the upstream side of the evaporators 1A and 1B.
The liquid refrigerant transfer pipe 6 and the hot gas transfer pipe 8 are flow rate adjusting valves 9A, 9B, 10A, 10B on the upstream side of the evaporators 1A, 1B and upstream of the junction of the liquid refrigerant transfer pipe 6 and the hot gas transfer pipe 8, respectively. It has. When the opening degree of the flow rate adjusting valves 9A, 9B, 10A, 10B is adjusted, the mixing ratio of the liquid refrigerant and the gas refrigerant mixed on the upstream side of the evaporators 1A, 1B changes. By adjusting the mixing ratio of the liquid refrigerant and the gas refrigerant, the temperature of the refrigerant flowing into the evaporators 1A and 1B is adjusted. Here, the temperature of the refrigerant flowing into the evaporator 1A of the first cargo compartment A and the temperature of the refrigerant flowing into the evaporator 1B of the second cargo compartment B by appropriately adjusting the flow rate adjusting valves 9A, 9B, 10A, 10B. Thus, the temperatures of the first cargo compartment A and the second cargo compartment B can be differentiated.

  By the way, in the refrigeration cycle system including a plurality of evaporators as described above, there is also a proposal that the evaporators are connected by a bypass circuit, and refrigerant is exchanged between the evaporators, thereby improving the utilization efficiency of heat energy as the whole system. (For example, refer to Patent Document 3)

US Pat. No. 4,706,468 International Publication No. 2006/031616 Pamphlet JP 2004-286428 A

In the technique described in Patent Document 3, in the operation mode in which heating is performed by one evaporator and cooling is performed by another evaporator, the refrigerant condensed by the evaporator that performs heating without passing the refrigerant through the condenser is cooled. Is sent to the evaporator through the bypass circuit, thereby increasing the utilization efficiency of heat energy.
However, in an actual refrigeration system, for example, depending on the balance between the heating conditions in one evaporator and the cooling conditions in another evaporator, the difference in the volume of the cargo compartments provided, and so on, , The required capabilities are often different. In such a case, in the technique described in Patent Document 3, when the necessary capacity of the evaporator that is cooling is higher than that of the evaporator that is heating, the bypass is condensed by the evaporator that is heating. With the amount of refrigerant supplied through the circuit, the amount of refrigerant is insufficient in the evaporator that is performing cooling. As a result, there arises a problem that the required cooling capacity cannot be exhibited in the evaporator performing the cooling.
That is, the technique described in Patent Document 3 can be used only under limited conditions in which the required ability is balanced between the evaporator that performs heating and the evaporator that performs cooling. However, it was not practical at all except when heating and cooling were always performed under the above-mentioned balanced and constant conditions.

  Furthermore, when the size of multiple evaporators is different from the beginning, or when a system configuration is provided with three or more evaporators, it is rare to perform heating and cooling balanced between the multiple evaporators. The above problem is particularly noticeable.

  The present invention has been made based on such a technical problem, and in a refrigeration cycle system including a plurality of evaporators, a refrigeration cycle system and a refrigeration cycle system capable of efficiently performing heating and cooling in parallel. It is an object to provide a control method.

The present invention made for this purpose is a refrigeration cycle system, a compressor for compressing a refrigerant to be a high-temperature and high-pressure gas refrigerant, a condenser for cooling the gas refrigerant to be a liquid refrigerant, and a condenser A plurality of evaporators for exchanging heat of the liquid refrigerant sent from the gas refrigerant and / or the gas refrigerant sent from the compressor with the surrounding atmosphere, a bypass path between the evaporators for sending the refrigerant from one evaporator to another evaporator, A control unit that controls a flow of the refrigerant in the system. Then, the control unit performs the heating operation with one evaporator, and performs the cooling operation with the other evaporator, and the liquid refrigerant condensed by heating with the one evaporator is transferred to the other evaporator by the bypass path between the evaporators. In the other evaporator, the ambient atmosphere is cooled by the liquid refrigerant sent from one evaporator and the liquid refrigerant sent from the condenser.
In this way, when the heating operation is performed with one evaporator and the cooling operation is performed with another evaporator, the liquid refrigerant condensed by heating with one evaporator and the liquid refrigerant sent from the condenser, By cooling the ambient atmosphere in another evaporator, it is possible to avoid a shortage of refrigerant.
If there are a plurality of evaporators, the number of evaporators is not limited to two but can be three or more.

  Such a method is preferably used when the amount of refrigerant necessary for performing cooling in another evaporator is larger than the amount of refrigerant necessary for performing heating with one evaporator.

In addition, a gas-liquid heat exchanger is provided on the upstream side of the evaporator, and a return path for sending the refrigerant that has passed through the evaporator to the gas-liquid heat exchanger is provided, and the refrigerant is sent to the evaporator between the gas-liquid heat exchanger and the evaporator. An electronic expansion valve that adjusts the amount of refrigerant can also be provided. Since the electronic expansion valve also functions to turn on / off the refrigerant supply to the evaporator, it is not necessary to provide an electromagnetic valve or the like upstream of the gas-liquid heat exchanger.
Further, a refrigerant pipe that sends the refrigerant from the gas-liquid heat exchanger to the evaporator and a bypass pipe that connects the return path are provided. The bypass pipe is downstream of the gas-liquid heat exchanger with respect to the refrigerant pipe, and It can be characterized by being connected at a position on the upstream side.

  In addition, a plurality of solenoid valves may be provided in parallel for adjusting the flow rate in a gas refrigerant supply pipe that supplies gas refrigerant sent from the compressor to the evaporator. This makes it possible to finely adjust the flow rate of the gas refrigerant sent from the compressor to the evaporator in multiple stages.

  The present invention includes a compressor that compresses a refrigerant to form a high-temperature and high-pressure gas refrigerant, a condenser that cools the gas refrigerant to form a liquid refrigerant, a liquid refrigerant sent from the condenser, and / or a compressor sent from the compressor. A control unit that controls a refrigeration cycle system that includes a plurality of evaporators that exchange heat of the gas refrigerant that comes with the surrounding atmosphere, and an evaporator-by-evaporator bypass passage that sends refrigerant from one evaporator to another evaporator. When the heating operation is performed with one evaporator and the cooling operation is performed with another evaporator, the liquid refrigerant condensed by heating with one evaporator is sent to the other evaporator through the bypass path between the other evaporators, and the other In the evaporator, the liquid refrigerant sent from one evaporator and the liquid refrigerant sent from the condenser It may be a control method of the refrigeration cycle system, characterized by cooling the 囲気.

  According to the present invention, when a heating operation is performed with one evaporator and a cooling operation is performed with another evaporator, the liquid refrigerant condensed by heating with one evaporator, and the liquid refrigerant sent from the condenser Accordingly, it is possible to avoid the shortage of the refrigerant by cooling the ambient atmosphere in another evaporator. Thereby, in a refrigeration cycle system including a plurality of evaporators, heating and cooling can be efficiently performed in parallel.

It is a figure which shows the structure of the refrigeration cycle system in 1st embodiment. It is a figure which shows the flow of the refrigerant | coolant in the case of performing heating and cooling in parallel. It is a figure which shows the flow of the refrigerant | coolant in the other case which performs a heating and cooling in parallel. It is a figure which shows the structure of the refrigerating cycle system in 2nd embodiment. It is a figure which shows the structure of the refrigerating cycle system provided with the conventional several evaporator.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
[First embodiment]
FIG. 1 is a diagram for explaining a configuration of a refrigeration cycle unit 20 in the present embodiment.
The refrigeration cycle unit 20 in the present embodiment is mounted on a vehicle such as a refrigeration truck. As shown in FIG. 1, the refrigeration cycle unit 20 includes a compressor 21 that compresses a refrigerant into a high-temperature / high-pressure gas, a condenser 22 that cools and liquefies the high-temperature / high-pressure refrigerant with outside air, and a condenser 22 The receiver 23 that separates air remaining in the refrigerant liquefied in step 3 and temporarily stores the liquefied refrigerant, and the evaporator 30A, the evaporator 30B, and the evaporator 30C that take heat away from the air in the cabinet and evaporate the refrigerant. Consists of.

  A box-shaped luggage compartment (not shown) provided at the rear of the vehicle is partitioned by a partition wall (not shown) to form a first cargo compartment A, a second cargo compartment B, and a third cargo compartment C. Has been. A host machine M1 having a compressor 21, a condenser 22, and an evaporator 30A is provided in the first cargo compartment A, and a remote machine M2 having an evaporator 30B is arranged in the second cargo compartment B. In the third cargo compartment C, a remote machine M3 having an evaporator 30C is arranged.

The liquid refrigerant transport pipe 24 that transports the liquid refrigerant sent from the condenser 22 via the receiver 23 branches into branch pipes (refrigerant pipes) 24a and 24b in the host machine M1, and the branch pipe 24a passes through the gas-liquid heat exchanger 32A. Connected to the evaporator 30A. The branch pipe 24b further branches into branch pipes (refrigerant pipes) 24c and 24d, and is connected to the evaporators 30B and 30C via gas-liquid heat exchangers 32B and 32C, respectively.
Further, a suction pipe 25 for sucking the refrigerant after heat exchange from the evaporators 30A, 30B, 30C is connected to the compressor 21 via the accumulator 31, and this suction pipe 25 is branched by the host machine M1. The branch pipe 25a is connected to the gas / liquid heat exchanger 32A, and the branch pipes 25b and 25c are connected to the gas / liquid heat exchangers 32B and 32C.

  Connected to the compressor 21 is a hot gas transfer pipe 26 that sends out a gas refrigerant that has been compressed to a high temperature and a high pressure, and the hot gas transfer pipe 26 is connected to a capacitor 22. The hot gas transfer pipe 26 is provided with a flow rate adjusting valve 40 and a discharge pressure adjusting valve 41 in parallel. Further, the hot gas transfer pipe 26 branches on the upstream side of the condenser 22, and the branch pipe 26a further branches into branch pipes 26b, 26c, and 26d, respectively, and on the upstream side of the evaporators 30A, 30B, and 30C, respectively. The refrigerant pipes 24 join the branch pipes 24a, 24c, and 24d.

  The branch pipes 24a, 24c and 24d of the liquid refrigerant transport pipe 24 and the branch pipes 26b, 26c and 26d of the hot gas transport pipe 26 branch from the branch pipe 24a and the branch pipe 26b, the branch pipe 24c and the branch pipe 26c, and the branch pipe 24d. Electronic expansion valves 27A, 27B, and 27C and flow rate adjustment valves 28A, 28B, and 28C are provided on the upstream side of the joining portion of the pipe 26d. Here, it is preferable to use solenoid valves for the flow rate adjusting valves 28A, 28B, and 28C.

Further, return pipes (return paths) 33a, 33b, and 33c are provided on the outlet sides of the evaporators 30A, 30B, and 30C, and are connected to the gas-liquid heat exchangers 32A, 32B, and 32C via the flow rate adjustment valves 34A, 34B, and 34C. It is connected. Here, it is preferable to use electromagnetic valves for the flow rate adjusting valves 34A, 34B, and 34C.
The bypass pipes 35a, 35b, and 35c branch from the middle of the return pipes 33a, 33b, and 33c, and join the upstream side of the electronic expansion valves 27A, 27B, and 27C with respect to the branch pipes 24a, 24c, and 24d of the liquid refrigerant transport pipe 24 is doing. These bypass pipes 35a, 35b, and 35c are provided with check valves 36A, 36B, and 36C.

In the refrigeration cycle unit 20 as described above, the electronic expansion valves 27A, 27B, 27C provided in the branch pipes 24a, 24c, 24d of the liquid refrigerant transport pipe 24 with the flow rate adjusting valves 28A, 28B, 28C closed. When the opening degree is adjusted, the circulation amount of the liquid refrigerant sent to the evaporators 30A, 30B, and 30C via the condenser 22 is adjusted, whereby the cooling temperature in the cabinet can be adjusted.
When the opening degree of the flow rate adjusting valves 28A, 28B, 28C provided in the branch pipes 26b, 26c, 26d of the hot gas transfer pipe 26 is adjusted with the electronic expansion valves 27A, 27B, 27C closed, the compressor 21 A high-temperature gas refrigerant (hot gas) can be sent to the evaporators 30A, 30B, and 30C without passing through the capacitor 22, and heating and defrosting in the cabinet can be performed.
Further, when the respective opening degrees are adjusted with the electronic expansion valves 27A, 27B, 27C and the flow rate adjusting valves 28A, 28B, 28C opened, the liquid refrigerant and the gas refrigerant mixed on the upstream side of the evaporators 30A, 30B, 30C The mixing ratio changes. The temperature of the refrigerant flowing into the evaporators 30A, 30B, and 30C can be adjusted by adjusting the mixing ratio of the liquid refrigerant and the gas refrigerant.
Furthermore, the temperature of the refrigerant flowing into the evaporator 30A of the first cargo compartment A can be appropriately and independently adjusted by opening the electronic expansion valves 27A, 27B, 27C and the flow rate adjusting valves 28A, 28B, 28C as described above. And the temperature of the refrigerant flowing into the evaporator 30B of the second cargo chamber B and the evaporator 30C of the third cargo chamber C, thereby making the first cargo chamber A, the second cargo chamber B, the third cargo The temperature of the chamber C can be adjusted individually.

The opening degree of the electronic expansion valves 27A, 27B, 27C and the flow rate adjusting valves 28A, 28B, 28C is adjusted by actuators (not shown) of the electronic expansion valves 27A, 27B, 27C and the flow rate adjusting valves 28A, 28B, 28C. This is done by controlling the operation (not shown).
In the control unit (not shown), the set temperatures of the first cargo compartment A, the second cargo compartment B, and the third cargo compartment C set by the driver of the vehicle and the refrigerant of the evaporators 30A, 30B, and 30C are set. The actuators of the electronic expansion valves 27A, 27B, 27C and the flow rate adjusting valves 28A, 28B, 28C are operated based on a preset program according to the discharge temperature, the refrigerant discharge pressure, the blown air temperature, the intake air temperature, and the like. Then, the opening is adjusted, and control is performed so that the room temperatures of the first cargo chamber A, the second cargo chamber B, and the third cargo chamber C approach the set temperature. The room temperature adjustment control of the first cargo compartment A, the second cargo compartment B, and the third cargo compartment C by adjusting the opening degree of the electronic expansion valves 27A, 27B, 27C and the flow rate regulating valves 28A, 28B, 28C is as follows. It can be performed by the same method as the conventional electronic expansion valve control.

  Further, since each of the host machine M1 and the remote machines M2 and M3 includes gas-liquid heat exchangers 32A, 32B and 32C, the check valves 36A, 36B and 36C are closed, and the flow rate adjusting valves 34A, 34B and 34C are closed. Is opened, heat exchange with the refrigerant having passed through the evaporators 30A, 30B, 30C is performed in the gas-liquid heat exchangers 32A, 32B, 32C. Thereby, it can cool more effectively with the refrigerant | coolant sent into evaporator 30A, 30B, 30C.

  Tables 1 to 3 show the flow rate adjustment valve 40 and the discharge pressure adjustment valve 41 of the hot gas transfer pipe 26 according to the operating conditions of the first cargo compartment A, the second cargo compartment B, and the third cargo compartment C. , Electronic expansion valves 27A, 27B, 27C, flow rate adjustment valves 28A, 28B, 28C, flow rate adjustment valves 34A, 34B, 34C, check valves 36A, 36B, 36C of the host machine M1, remote machine M2, M3 An example is given. Here, when cooling is performed only in the first cargo room A, the second cargo room B, and the third cargo room C, Table 1 shows the first cargo room A and the second cargo room. B, when only heating is performed in the third loading chamber C, Table 3 is an example in which heating and cooling are performed in the first loading chamber A, the second loading chamber B, and the third loading chamber C. is there.

Here, attention is focused on the first and second examples from the left in Table 3.
When cooling is performed by the host machine M1 and the remote machine M2 from the left in Table 3 and heating is performed by the remote machine M3, the liquid that has passed through the compressor 21, the condenser 22, and the receiver 23 as shown in FIG. The refrigerant is sent to the host machine M1 and the remote machine M2 through the liquid refrigerant transport pipe 24 and the branch pipes 24a, 24b, and 24c.
In the host machine M1, the liquid refrigerant sent through the branch pipe 24a is sent into the evaporator 30A via the gas-liquid heat exchanger 32A and the electronic expansion valve 27A. In the evaporator 30A, the first cargo compartment A is cooled by exchanging heat with the interior atmosphere. The refrigerant evaporated through the evaporator 30A passes through the gas / liquid heat exchanger 32A through the return pipe 33a and the flow rate adjusting valve 34A. After the heat exchange with the liquid refrigerant passing through the branch pipe 24 a by the gas-liquid heat exchanger 32 </ b> A, the refrigerant is circulated from the branch pipe 25 a of the suction pipe 25 through the accumulator 31 to the compressor 21.
Similarly, in the remote machine M2 that performs cooling, the liquid refrigerant sent through the branch pipes 24b and 24c is sent to the evaporator 30B through the gas-liquid heat exchanger 32B and the electronic expansion valve 27B. In the evaporator 30B, the second cargo room B is cooled by exchanging heat with the interior atmosphere. The refrigerant evaporated through the evaporator 30B passes through the return pipe 33b and the flow rate adjustment valve 34B, and then passes through the gas-liquid heat exchanger 32B. After the heat exchange with the liquid refrigerant passing through the branch pipe 24 c in the gas-liquid heat exchanger 32 B, the refrigerant is circulated from the branch pipe 25 b of the suction pipe 25 through the accumulator 31 to the compressor 21.

On the other hand, in the remote machine M3 that performs heating, the high-temperature refrigerant sent from the compressor 21 is sent to the evaporator 30C via the branch pipes 26a and 26d of the hot gas transfer pipe 26 and the flow rate adjustment valve 28C. In the evaporator 30C, the third cargo compartment C is heated by exchanging heat between the high-temperature refrigerant and the interior atmosphere. The refrigerant condensed by the heat exchange in the evaporator 30C passes between the vapor-liquid heat exchanger 32C and the electronic expansion valve 27C via the return pipe 33c, the bypass pipe 35c, and the check valve 36C which are bypass paths between the evaporators. It flows into the branch pipe 24d. Then, after passing through the gas-liquid heat exchanger 32C, the refrigerant flows into the junction of the branch pipes 24b, 24c, and 24d, and flows into at least the branch pipe 24c. The refrigerant flowing into the branch pipe 24c is sent to the evaporator 30B. Further, the refrigerant may flow from the branch pipe 24d to the branch pipe 24b according to the pressure loss of the refrigerant in the branch pipes 24b and 24c at that time, and this refrigerant passes through the branch pipe 24a from the branch pipe 24b. It is sent to 30A.
That is, the refrigerant condensed by the evaporator 30C of the remote machine M3 that performs heating is sent to the evaporators 30A and 30B and used as a heat source for cooling in the host machine M1 and the remote machine M2.

In addition, when cooling is performed by the host machine M1 and the remote machine M3, which is the second from the left in Table 3, and heating is performed by the remote machine M2, the compressor 21, the condenser 22, and the receiver 23 are connected as shown in FIG. The passed liquid refrigerant is sent to the host machine M1 and the remote machine M3 through the liquid refrigerant transport pipe 24 and the branch pipes 24a, 24b, and 24d.
In the host machine M1, the refrigerant sent by the branch pipe 24a is sent to the evaporator 30A via the gas-liquid heat exchanger 32A and the electronic expansion valve 27A. In the evaporator 30A, the first cargo compartment A is cooled by exchanging heat with the interior atmosphere. The refrigerant evaporated through the evaporator 30A passes through the gas / liquid heat exchanger 32A through the return pipe 33a and the flow rate adjusting valve 34A. After the heat exchange with the liquid refrigerant passing through the branch pipe 24 a by the gas-liquid heat exchanger 32 </ b> A, the refrigerant is circulated from the branch pipe 25 a of the suction pipe 25 through the accumulator 31 to the compressor 21.
Similarly, in the remote machine M3 that performs cooling, the refrigerant sent through the branch pipes 24b and 24d is sent to the evaporator 30C through the gas-liquid heat exchanger 32C and the electronic expansion valve 27C. In the evaporator 30C, the third cargo compartment C is cooled by exchanging heat with the interior atmosphere. The refrigerant evaporated through the evaporator 30C passes through the gas / liquid heat exchanger 32C through the return pipe 33c and the flow rate adjustment valve 34C. After the heat exchange with the liquid refrigerant passing through the branch pipe 24d by the gas-liquid heat exchanger 32C, the refrigerant is circulated from the branch pipe 25c of the suction pipe 25 through the accumulator 31 to the compressor 21.

On the other hand, in the remote machine M2 that performs heating, the high-temperature refrigerant sent from the compressor 21 is sent to the evaporator 30B via the branch pipes 26a and 26c of the hot gas transfer pipe 26 and the flow rate adjustment valve 28B. In the evaporator 30B, the second cargo compartment B is heated by exchanging heat between the high-temperature refrigerant and the internal atmosphere. The refrigerant condensed by the heat exchange in the evaporator 30B passes through the return pipe 33b, the bypass pipe 35b, and the check valve 36B, which are bypass paths between the evaporators, and between the gas-liquid heat exchanger 32B and the electronic expansion valve 27B. It flows into the branch pipe 24c. Then, after passing through the gas-liquid heat exchanger 32B, the refrigerant flows toward the junction of the branch pipes 24b, 24c, and 24d, and flows into at least the branch pipe 24d. The refrigerant that has flowed into the branch pipe 24d is sent to the evaporator 30C. Further, the refrigerant may flow from the branch pipe 24c to the branch pipe 24b according to the pressure loss of the refrigerant in the branch pipes 24b and 24d at that time, and this refrigerant passes through the branch pipe 24a from the branch pipe 24b. It is sent to 30A.
That is, the refrigerant condensed by the evaporator 30B of the remote machine M2 that performs heating is sent to the evaporators 30A and 30C and used as a heat source for cooling in the host machine M1 and the remote machine M3.

  In this way, when heating and cooling are performed in parallel in the host machine M1 and the remote machines M2 and M3, the refrigerant condensed by the condenser 22 and the refrigerant condensed by the evaporator 30B or 30C that is heating are cooled. Is fed to the evaporator 30A and the evaporator 30C or 30C. By using the refrigerant condensed in the evaporator 30B or 30C that is heating and cooling with the other evaporator 30A and the evaporator 30C or 30C, the capacity on the cooling side is increased and the utilization efficiency of heat energy is increased. Can do. In addition, by sending the refrigerant from the condenser 22 as well, it is possible to avoid a shortage of cooling refrigerant even when heating is performed by a single evaporator 30B or 30C having a small capacity. Therefore, it is possible to always perform an efficient operation in a variable manner corresponding to various conditions and operation states.

  Further, electronic expansion valves 27A, 27B, and 27C are provided on the upstream side of the evaporators 30A, 30B, and 30C instead of the mechanical type. As a result, the flow rate can be adjusted more finely than when a mechanical flow rate adjustment valve is provided. Further, the electronic expansion valves 27A, 27B, and 27C have a function of opening and closing the branch pipes 24a, 24c, and 24d that supply the refrigerant to the evaporators 30A, 30B, and 30C, and therefore, upstream of the gas-liquid heat exchangers 32A, 32B, and 32C. There is no need to provide a separate solenoid valve on the side.

  In addition, by providing the gas-liquid heat exchangers 32B and 32C in the remote machines M2 and M3, the supercooling of the evaporators 30B and 30C can be performed independently without depending on the operating state of the other cargo compartments.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described.
The entire configuration of the refrigeration cycle unit 50 shown in the present embodiment is common to the refrigeration cycle unit 20 shown in the first embodiment. Therefore, in the following description, the description will be focused on the differences from the refrigeration cycle unit 20 shown in the first embodiment, and the same reference numerals are given to the configurations common to the first embodiment. Therefore, the description is omitted.
As shown in FIG. 4, the refrigeration cycle unit 50 includes a plurality of units (3 in the example of FIG. 4) in the branch pipe 26b of the hot gas transfer pipe 26, instead of the flow rate adjustment valve 28A in the first embodiment. The base is provided with flow control valves (solenoid valves) 28A-1, 28A-2, 28A-3 arranged in parallel. The flow rate of the hot gas refrigerant passing through the branch pipe 26b can be adjusted in multiple stages by the combination of opening and closing of the flow rate adjusting valves 28A-1, 28A-2, 28A-3.
In addition, on the upstream side of the branch point of the branch pipes 26c and 26d of the hot gas transfer pipe 26, a plurality of units (three units in the example of FIG. 4) are arranged in parallel and flow rate adjusting valves (solenoid valves) 28D-1, 28D-2 and 28D-3 are provided.

The flow rate adjusting valves 28A-1, 28A-2, 28A-3, 28D-1, 28D-2, and 28D-3 are combined to open and close to the evaporators 30A, 30B, and 30C through the branch pipes 26b, 26c, and 26d. The flow rate of the hot gas refrigerant to be fed can be adjusted in multiple stages. Thereby, temperature adjustment with higher accuracy is possible in the evaporators 30A, 30B, and 30C.
Further, by using a plurality of flow rate adjusting valves 28A-1, 28A-2, 28A-3, 28D-1, 28D-2, 28D-3, the amount of hot gas condensed in the evaporators 30A, 30B, 30C is adjusted. Therefore, it is possible to prevent the refrigerant from returning to the accumulator 31 and the compressor 21.

In the above-described embodiment, the configuration of the refrigeration cycle units 20 and 50 is shown. However, the basic configuration is merely shown, and it is needless to say that appropriate changes can be made.
In addition to the host machine M1, a configuration including two remote machines M2 and M3 has been described. However, a configuration including three or more remote machines can also be developed by developing the same configuration as described above. Obviously it can be easily realized.
In addition to this, as long as it does not depart from the gist of the present invention, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate.

  DESCRIPTION OF SYMBOLS 20 ... Refrigeration cycle unit, 21 ... Compressor, 22 ... Condenser, 23 ... Receiver, 24 ... Liquid refrigerant transport pipe, 24a, 24b, 24c, 24d ... Branch pipe (refrigerant pipe), 25 ... Suction pipe, 25a, 25b, 25c ... Branch pipe, 26 ... Hot gas transfer pipe, 26a, 26b, 26c, 26d ... Branch pipe, 27A, 27B, 27C ... Electronic expansion valve, 28A, 28B, 28C ... Flow rate adjusting valve, 28A-1, 28A-2 , 28A-3 ... Flow rate adjusting valve (solenoid valve), 28D-1, 28D-2, 28D-3 ... Flow rate adjusting valve (solenoid valve), 30A, 30B, 30C ... Evaporator, 31 ... Accumulator, 32A, 32B, 32C ... gas-liquid heat exchangers, 33a, 33b, 33c ... return pipes (return paths), 34A, 34B, 34C ... flow control valves, 35a, 35b, 35c ... bypass pipes, 3 A, 36B, 36C ... check valve, 40 ... flow control valve, 41 ... discharge pressure regulating valve, 50 ... refrigerating cycle unit

Claims (6)

A refrigeration cycle system,
A compressor that compresses the refrigerant into a high-temperature, high-pressure gas refrigerant;
A condenser that cools the gas refrigerant to form a liquid refrigerant;
A plurality of evaporators for exchanging heat of the liquid refrigerant sent from the capacitor and / or the gas refrigerant sent from the compressor with an ambient atmosphere;
An inter-evaporator bypass path for sending refrigerant from one evaporator to the other evaporator;
A controller for controlling the flow of refrigerant in the system;
With
The control unit performs a heating operation with one of the evaporators, and performs a cooling operation with the other evaporator, and causes the liquid refrigerant condensed by heating with the one evaporator to the other evaporator. The ambient atmosphere is cooled by the liquid refrigerant fed from one evaporator and the liquid refrigerant fed from the condenser in the other evaporator, which is fed through the bypass path between the evaporators. Refrigeration cycle system.   2. The refrigeration cycle unit according to claim 1, wherein an amount of refrigerant necessary for cooling in another evaporator is larger than an amount of refrigerant necessary for performing heating in one of the evaporators.   A gas-liquid heat exchanger is provided on the upstream side of the evaporator, and a return path for sending the refrigerant that has passed through the evaporator to the gas-liquid heat exchanger is provided, between the gas-liquid heat exchanger and the evaporator. The refrigeration cycle system according to claim 1 or 2, further comprising an electronic expansion valve that adjusts an amount of refrigerant sent to the evaporator.   A bypass pipe that connects the return pipe to the refrigerant pipe that sends the refrigerant from the gas-liquid heat exchanger to the evaporator is provided, and the bypass pipe is downstream of the gas-liquid heat exchanger with respect to the refrigerant pipe. The refrigeration cycle system according to claim 3, wherein the refrigeration cycle system is connected at a position upstream of the evaporator.   2. A plurality of solenoid valves are provided in parallel for adjusting the flow rate in a gas refrigerant supply pipe for supplying the gas refrigerant sent from the compressor to the evaporator. 5. The refrigeration cycle system according to any one of 4 to 4. A compressor that compresses the refrigerant into a high-temperature, high-pressure gas refrigerant;
A condenser that cools the gas refrigerant to form a liquid refrigerant;
A plurality of evaporators for exchanging heat of the liquid refrigerant sent from the capacitor and / or the gas refrigerant sent from the compressor with an ambient atmosphere;
An inter-evaporator bypass path for sending refrigerant from one evaporator to the other evaporator;
In the control unit that controls the refrigeration cycle system equipped with
When the heating operation is performed by one evaporator and the cooling operation is performed by another evaporator, the liquid refrigerant condensed by heating by the one evaporator is transferred to the other evaporator by the bypass path between the evaporators. In the other evaporator, the ambient atmosphere is cooled by the liquid refrigerant sent from one evaporator and the liquid refrigerant sent from the capacitor. Control method.

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