WO2015177852A1

WO2015177852A1 - Refrigeration cycle device

Info

Publication number: WO2015177852A1
Application number: PCT/JP2014/063266
Authority: WO
Inventors: 博幸岡野
Original assignee: 三菱電機株式会社
Priority date: 2014-05-19
Filing date: 2014-05-19
Publication date: 2015-11-26
Also published as: GB2541607A; JP6042037B2; GB201620966D0; JPWO2015177852A1; GB2541607B

Abstract

A refrigeration cycle device equipped with: a heat storage unit that is provided between multiple heat-source-side units and load-side units, and that performs a heat exchange with a refrigerant flowing between the multiple heat-source-side units and load-side units; a heat storage switching device that switches between a flow path that introduces refrigerant from the multiple heat-source-side units to the heat storage unit and a flow path that introduces refrigerant from the load-side units to the heat storage unit; a heat-source-side unit selection unit that, when the heat storage switching device switches to the flow path for introducing refrigerant from the load-side units to the heat storage unit, selects a heat-source-side unit into which the refrigerant flowing from the heat storage unit is introduced; and a control device that performs a control so as to turn off a first on-off valve and turn on a second on-off valve in the heat-source-side unit selected by the heat-source-side selection unit.

Description

Refrigeration cycle equipment

The present invention relates to a refrigeration cycle apparatus including a plurality of heat source units.

BACKGROUND ART Conventionally, a refrigeration cycle apparatus having a heat storage tank is known, and an air conditioner that can heat a room during defrost operation using heat stored in the heat storage tank has been proposed (for example, Patent Document 1). reference). In Patent Document 1, in the heating and heat storage operation mode, the use side heat exchanger and the heat storage heat exchanger function as a condenser, and the heat source side heat exchanger functions as an evaporator. An air conditioner in which an exchanger functions as a condenser and a heat storage heat exchanger functions as an evaporator is disclosed. That is, in Patent Document 1, the heat stored in the heat storage tank during the heating and heat storage operation mode is collected during the defrost operation, so that the heating operation is continued even during the defrost operation.

Japanese Patent No. 4457755

In Patent Document 1, one heat storage tank is connected to one heat source machine. When this is applied to a refrigeration cycle apparatus including a plurality of heat source side units, heat storage tanks corresponding to the number of heat source side units are required, which increases installation space and costs.

The present invention has been made to solve the above-described problems, and provides an air conditioner capable of performing defrosting using a heat storage unit on a plurality of heat source side units while saving space. It is an object.

The refrigeration cycle apparatus of the present invention includes a plurality of heat source side units in which a compressor, a flow path switch, and a heat source side heat exchanger are connected in order, and a plurality of heat source side units, and a load side heat exchanger. A refrigeration cycle apparatus in which a refrigerant circuit in which refrigerant circulates between the plurality of heat source side units and the load side unit is configured, and each heat source side unit is connected to the heat source from the load side unit. A first on-off valve provided on the refrigerant flow path flowing into the side heat exchanger, a bypass pipe connecting the discharge side of the compressor and the heat source side heat exchanger, and provided on the bypass pipe, from the compressor to the heat source A second on-off valve that controls the inflow of refrigerant into the side heat exchanger, provided between the plurality of heat source side units and the load side unit, and between the plurality of heat source side units and the load side unit. Refrigerant and heat flowing between In a heat storage switching unit that switches between a heat storage unit that performs conversion, a flow path through which refrigerant flows from the plurality of heat source side units to the heat storage unit, and a flow path through which refrigerant flows from the load side unit to the heat storage unit, The heat source side unit selection unit that selects the heat source side unit that causes the refrigerant that has flowed out of the heat storage unit to flow in, and the heat source side unit selection unit are selected when the flow path is switched from the load side unit to the heat storage unit. The heat source side unit includes a control device that controls the first on-off valve to be in a closed state and the second on-off valve to be in an open state.

According to the air conditioner of the present invention, in the heat source side unit selected by the heat source side unit selector, by controlling the first on-off valve to be in the closed state and the second on-off valve to be in the open state. Since it is possible to defrost a plurality of heat source side units using a smaller number of heat storage units than the heat source side units, it is possible to defrost the heat source side unit using the heat storage unit while saving space. .

It is a refrigerant circuit figure showing an example of the refrigerating cycle device concerning an embodiment of the invention. It is a refrigerant circuit figure which shows the flow of the refrigerant | coolant at the time of the heating only operation mode of the refrigerating-cycle apparatus of FIG. It is a refrigerant circuit figure which shows the flow of the refrigerant | coolant at the time of the defrost operation mode of the refrigeration cycle apparatus of FIG. FIG. 4 is a flowchart showing an example of the operation of the heat source unit selector 24 during the defrost operation of FIG. It is a graph which shows an example of control of the operating frequency of the compressor in the refrigerating cycle device of Drawing 1.

Embodiment 1. FIG.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram illustrating an example of a refrigeration cycle apparatus according to an embodiment of the present invention. The refrigeration cycle apparatus 1 will be described with reference to FIG. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one.

The refrigeration cycle apparatus 1 is installed in, for example, a building or a condominium, and performs a mixed cooling / heating operation using a refrigeration cycle (heat pump cycle) that circulates refrigerant. The refrigeration cycle apparatus 1 includes a plurality of heat

source side units

10A and 10B, one heat storage unit 20, a refrigerant control unit 30, and a plurality of

load side units

40A and 40B. The unit 20, the refrigerant control unit 30, and the

load side units

40A and 40B are connected in this order.

The plurality of heat

source side units

10A and 10B are connected to the heat storage unit 20 via the

low pressure pipes

2A and 2B and the

high pressure pipes

3A and 3B, respectively. Specifically, the

low pressure pipes

2A and 2B are connected to the low pressure joining pipe 2C, and the low pressure joining pipe 2C is connected to the heat storage unit 20 via the low pressure pipe 2D. The low-pressure merging pipe 2C branches the refrigerant flowing from the heat storage unit 20 via the low-pressure pipe 2D into the low-

pressure pipes

2A and 2B and flows into the respective heat

source side units

10A and 10B.

Further, the

high pressure pipes

3A and 3B are connected to the high pressure joining pipe 3C, and the high pressure joining pipe 3C is connected to the heat storage unit 20 via the high pressure pipe 3D. The high-pressure merging pipe 3C joins the refrigerant flowing through each of the high-

pressure pipes

3A and 3B, and flows the combined refrigerant into the heat storage unit 20 via the high-pressure pipe 3D. Furthermore, the plurality of heat

source side units

10A and 10B are individually connected to the heat storage unit 20 via the

pipes

5A and 5B, respectively, and the plurality of heat

source side units

10A and 10A are connected from the heat storage unit 20 via the

pipes

5A and 5B, respectively. The refrigerant flows into each of 10B. As described above, the plurality of heat

source side units

10A and 10B and the heat storage unit 20 are connected using four pipes of the low pressure pipe 2D, the high pressure pipe 3D, and the

pipes

5A and 5B.

The heat storage unit 20 and the refrigerant control unit 30 are connected by two pipes, a low pressure pipe 2E and a high pressure pipe 3D. The refrigerant control unit 30 and the plurality of load-

side units

40A and 40B are connected to each other by

liquid pipes

6A and 6B and

gas pipes

7A and 7B. Thus, the plurality of heat

source side units

10A and 10B, the heat storage unit 20, the refrigerant control unit 30, and the plurality of

load side units

40A and 40B form one refrigeration cycle.

Using this refrigeration cycle as a refrigerant, for example, natural refrigerants such as carbon dioxide, hydrocarbons, and helium, alternative refrigerants that do not contain chlorine such as HFC410A, HFC407C, and HFC404A, or chlorofluorocarbons such as R22 and R134a that are used in existing products Various known refrigerants such as a refrigerant can be used.

[Heat

source side units

10A, 10B]
The plurality of heat

source side units

10A and 10B have a function of supplying cold or warm heat to the

load side units

40A and 40B. In addition, although illustrated below about the case where several heat

source side unit

10A, 10B has the same structure, you may have a different structure.

Each of the heat

source side units

10A and 10B includes a compressor 11, a first flow path switch 12, a heat source side heat exchanger 13, and an accumulator 14, and constitutes a refrigerant circuit in which these are connected in series. is doing. The compressor 11 sucks a low-temperature / low-pressure gas refrigerant, compresses the refrigerant into a high-temperature / high-pressure gas refrigerant, and circulates the refrigerant in the system to perform an air-conditioning operation. The compressor 11 may be a known compressor such as an inverter type compressor capable of capacity control, a constant speed type compressor, or a compressor combined with an inverter type and a constant speed type. The compressor 11 is not particularly limited as long as it can compress the sucked refrigerant into a high pressure state. For example, the compressor 11 can be configured using various types such as reciprocating, rotary, scroll, or screw.

The first flow path switch 12 is composed of, for example, a four-way valve, is provided on the discharge side of the compressor 11, and switches the refrigerant flow path between the cooling operation and the heating operation. During the heating operation, the first flow path switch 12 connects the heat source side heat exchanger 13 and the accumulator 14, and connects the discharge side of the compressor 11 and the check valve 15c. Then, the refrigerant discharged from the compressor 11 flows to the heat storage unit 20 side. On the other hand, during the cooling operation, the first flow path switch 12 connects the accumulator 14 and the check valve 15a, and connects the discharge side of the compressor 11 and the heat source side heat exchanger 13. Then, the refrigerant discharged from the compressor 11 flows to the heat source side heat exchanger 13 side. In addition, although illustrated about the case where a four-way valve is used as the 1st flow path switching device 12, you may comprise not only this but combining several two-way valves etc., for example.

The heat source side heat exchanger 13 exchanges heat between a heat medium such as ambient air or water and a refrigerant, evaporates and gasifies the refrigerant as an evaporator during heating operation, and a condenser (radiator) during cooling operation. The refrigerant is condensed and liquefied. The heat source side heat exchanger 13 is composed of an air-cooled heat exchanger such as a fin tube type heat exchanger, for example, and a blower 13A for controlling the heat exchange amount of the heat source side heat exchanger 13 is installed. . And the condensation capability or the evaporation capability is controlled by controlling the rotation speed of the blower 13A. In addition, although illustrated about the case where the heat source side heat exchanger 13 consists of an air-cooling type heat exchanger, you may consist of a water-cooling type heat exchanger. In this case, the condensation capacity or the evaporation capacity is controlled by the rotation speed of the water circulation pump.

The accumulator 14 is provided on the suction side of the compressor 11 and has a function of storing excess refrigerant and a function of separating liquid refrigerant and gas refrigerant. The compressor 11 sucks and compresses the gas refrigerant among the refrigerant stored in the accumulator 14.

In addition, the heat source side unit 10A includes four types for making the flow of the refrigerant flowing into the heat storage unit 20 in a certain direction in any of the heating flow path and the cooling flow path switched by the first flow path switching device 12. Check valves 15a to 15d are provided. The check valve 15 a is located between the first flow path switch 12 and the low pressure pipe 2 A and allows the refrigerant flow from the low pressure pipe 2 A toward the first flow path switch 12. The check valve 15b is located between the low pressure pipe 2A and the heat source side heat exchanger 13, and allows the refrigerant to flow from the low pressure pipe 2A toward the heat source side heat exchanger 13. The check valve 15c is located between the first flow path switch 12 and the high pressure pipe 3A, and allows the refrigerant flow from the first flow path switch 12 to the high pressure pipe 3D. The check valve 15d is located between the heat source side heat exchanger 13 and the high pressure pipe 3A and allows the refrigerant flow from the heat source side heat exchanger 13 toward the

high pressure pipes

3A and 3B.

Furthermore, the heat source side unit 10A makes the flow of the refrigerant flowing into the heat source side heat exchanger 13 in a certain direction in any case of the heating flow path or the cooling flow path switched by the first flow path switching device 12. 4 check valves 16a to 16d are provided. The check valve 16 a is located between the first flow path switch 12 and the heat source side heat exchanger 13 and allows the refrigerant flow from the first flow path switch 12 to the heat source side heat exchanger 13. The check valve 16b is located between the high pressure pipe 3A and the heat source side heat exchanger 13, and allows the refrigerant flow from the high pressure pipe 3A toward the heat source side heat exchanger 13. The check valve 16 c is located between the heat source side heat exchanger 13 and the accumulator 14 and allows the refrigerant flow from the heat source side heat exchanger 13 to the accumulator 14. The check valve 16d is located between the heat source side heat exchanger 13 and the high pressure pipe 3A and allows the refrigerant flow from the heat source side heat exchanger 13 toward the high pressure pipe 3A.

The heat

source side units

10A and 10B include a first on-off valve 17, a bypass pipe 18, and a second on-off valve 19 provided on the refrigerant inflow side of the heat source side heat exchanger 13, respectively. The first on-off valve 17 is provided on the refrigerant flow path that flows from the load side units 40 A and 40 B to the heat source side heat exchanger 13, and is connected to the heat source side heat exchanger via the first flow path switch 12. The refrigerant | coolant flow volume which flows into 13 is controlled by opening / closing operation | movement.

The bypass pipe 18 connects the discharge side of the compressor 11 and the heat source side heat exchanger 13, and the second on-off valve 19 is provided on the bypass pipe 18, and is connected to the heat source side heat exchanger 13 from the compressor 11. It controls the inflow of the refrigerant to. During the defrost operation, the first on-off valve 17 is controlled to be closed, and the second on-off valve 19 is controlled to be open. Then, the gas refrigerant discharged from the compressor 11 flows into the heat source side heat exchanger 13, and frost attached to the heat source side heat exchanger 13 can be melted (hot gas defrost).

[Heat storage unit 20]
The heat storage unit 20 is interposed between the heat

source side units

10A and 10B and the refrigerant control unit 30, stores heat quantity supplied from the heat

source side units

10A and 10B, and becomes a heat collection source during the defrost operation. The heat storage unit 20 includes a heat storage flow path switch 21, a heat storage unit 22, a refrigerant branching unit 23, and a heat source unit selection unit 24.
The heat storage flow path switching device 21 includes, for example, a four-way valve and the like. The flow path through which the refrigerant flows from the plurality of heat

source side units

10A and 10B to the heat storage unit 22 and the refrigerant from the

load side units

40A and 40B to the heat storage unit 22 Is switched to the flow path into which the gas flows. That is, during the heating operation, the heat storage flow path switch 21 causes a part of the refrigerant flowing through the high-pressure pipe 3D to flow into the heat storage heat exchanger 22B side. On the other hand, during the defrost operation, the heat storage flow path switching device 21 switches the refrigerant flowing out of the heat storage heat exchanger 22B to flow out to the heat

source side units

10A and 10B via the heat source unit selection unit 24.

The heat storage section 22 is provided between the plurality of heat

source side units

10A and 10B and the

load side units

40A and 40B, and flows between the plurality of heat

source side units

10A and 10B and the

load side units

40A and 40B. Heat exchange. Specifically, the heat storage unit 22 has a structure in which a heat storage heat exchanger 22B is accommodated in a heat storage tank 22A in which a medium such as heat storage water is stored. One of the heat storage heat exchangers 22 B is connected to the heat storage flow path switch 21, and the other is connected to the refrigerant branch portion 23.

The refrigerant branching section 23 joins or branches the refrigerant flowing from the low pressure pipe 2E to the low pressure pipe 2D and the heat storage heat exchanger 22B according to the operation mode. The refrigerant branching section 23 includes a check valve 23a and a throttle device 23b arranged so as to be connected in parallel with each other between the heat storage flow path switch 21 and the low pressure pipe 2E. The check valve 23a is attached so as to allow the refrigerant to flow from the low pressure pipe 2E toward the heat storage heat exchanger 22B. The expansion device 23b decompresses the refrigerant that has flowed out of the heat storage heat exchanger 22B.

In the heating operation mode, the refrigerant branching portion 23 flows out of the refrigerant control unit 30 through the low pressure pipe 2E and the check valve 23a, and flows out of the heat storage heat exchanger 22B and is decompressed in the expansion device 23b. The refrigerant has merged and flows to the low pressure pipe 2D side. On the other hand, in the defrosting operation mode, the refrigerant branching unit 23 branches the refrigerant flowing from the refrigerant control unit 30 through the low pressure pipe 2E and the check valve 23a into the low pressure pipe 2D and the heat storage heat exchanger 22B.

The heat source unit selector 24 supplies the refrigerant flowing out of the heat storage heat exchanger 22B during the defrost operation to the heat source side unit 10A or the heat source side unit 10B in which the defrost operation is performed. The heat source unit selector 24 includes a first heat storage side on / off valve 24A connected to the heat source side unit 10A via the pipe 5A, and a second heat storage side on / off valve 24B connected to the heat source side unit 10B via the pipe 5B. have. When the first heat storage side opening / closing valve 24A is opened and the second heat storage side opening / closing valve 24B is closed, the refrigerant flows from the heat storage heat exchanger 22B to the heat source side unit 10A. On the other hand, when the first heat storage side opening / closing valve 24A is closed and the second heat storage side opening / closing valve 24B is opened, the refrigerant flows from the heat storage heat exchanger 22B to the heat source side unit 10B.

In FIG. 1, the heat storage unit 20 is a separate unit from the heat

source side units

10A and 10B, but may be built in any one of the heat

source side units

10A and 10B. Furthermore, although illustrated about the case where the heat source unit selection part 24 is provided in the heat storage unit 20, you may provide in each heat

source side unit

10A, 10B, and the heat

source side unit

10A, 10B, the heat storage unit 20, and You may provide between.

[Refrigerant control unit 30]
The refrigerant control unit 30 is interposed between the load-

side units

40A, 40B and the heat storage unit 20, and distributes the refrigerant to the load-

side units

40A, 40B, and according to the operating conditions of the load-

side units

40A, 40B. The refrigerant flow is switched. The refrigerant control unit 30 includes a gas-liquid separator 31, a second flow path switch 32, a first inter-refrigerant heat exchanger 33, a second inter-refrigerant heat exchanger 34, a first throttling device 35, and a second throttling device 36. I have.

The gas-liquid separator 31 is provided in the high pressure pipe 3D and has a function of separating the two-phase refrigerant flowing through the high pressure pipe 3D into a gas refrigerant and a liquid refrigerant. The gas refrigerant separated by the gas-liquid separator 31 is supplied to the second flow path switch 32 via the first connection pipe 37, and the liquid refrigerant is supplied to the first inter-refrigerant heat exchanger 33. The gas-liquid separator 31 is not limited in its method and shape as long as it separates the two-phase refrigerant into a gas phase and a liquid phase, and for example, a method such as gravity separation or centrifugal separation can be adopted. Further, the separation efficiency of the gas-liquid separator 31 is not limited, and may be selected according to the amount of liquid back, the circulation amount of the refrigerant, the target performance value, the target cost, and the like that are acceptable in the system.

The second flow path switch 32 controls the supply of refrigerant to the

load side units

40A and 40B according to the operation mode, and is connected to the

liquid pipes

6A and 6B and the

gas pipes

7A and 7B. The second flow path switching device 32 includes first open /

close valves

32a and 32b and second open /

close valves

32c and 32d. The first on-off

valves

32a and 32b have one end connected to the gas-liquid separator 31 and the other end connected to the

gas pipes

7A and 7B of the

load side units

40A and 40B, respectively. The second on-off

valves

32c and 32d have one end connected to the low pressure pipe 2E and the other end connected to one end side of the refrigerant flow path of each of the

load side units

40A and 40B.

The opening and closing of the first on-off

valves

32a and 32b and the second on-off

valves

32c and 32d are independently controlled based on the operation mode of the

load side units

40A and 40B. During the heating operation of the

load side units

40A and 40B, the first on-off

valves

32a and 32b are opened, and the second on-off

valves

32c and 32d are closed. Then, the refrigerant flows from the gas-liquid separator 31 side to the

load side units

40A and 40B via the first on-off

valves

32a and 32b. On the other hand, during the cooling operation of the load-

side units

40A and 40B, the first on-off

valves

32a and 32b are closed, and the second on-off

valves

32c and 32d are opened. Then, the refrigerant flows from the

load side units

40A, 40B side to the low pressure pipe 2E side via the second on-off

valves

32c, 32d. In addition, although illustrated about the case where the 1st on-off

valves

32a and 32b and the 2nd on-off

valves

32c and 32d are comprised by the solenoid valve, you may use a three-way valve etc., for example. In this way, by switching the refrigerant flow in the second flow path switching unit 32, the cooling operation or the heating operation can be independently controlled in each of the

load side units

40A and 40B.

The first inter-refrigerant heat exchanger 33 is provided between the gas-liquid separator 31 and the first throttling device 35, and the refrigerant that has flowed out of the gas-liquid separator 31 and the second inter-refrigerant heat exchanger 34. Heat exchange is performed with the refrigerant that has flowed out. The second inter-refrigerant heat exchanger 34 exchanges heat between the refrigerant flowing out of the first expansion device 35 and the refrigerant flowing out of the second expansion device 36.

The first expansion device 35 is provided between the gas-liquid separator 31 and the

liquid pipes

6A and 6B (between the first inter-refrigerant heat exchanger 33 and the second inter-refrigerant heat exchanger 34). It functions as a valve or an expansion valve, and expands the refrigerant by decompressing it. The first throttling device 35 may be configured by a device whose opening degree can be variably controlled, for example, a precise flow rate control device using an electronic expansion valve, an inexpensive refrigerant flow rate control means such as a capillary tube, or the like.

The second expansion device 36 is provided upstream of the second refrigerant heat exchanger 34 on the secondary side of the second connection pipe 38 and has a function as a pressure reducing valve or an expansion valve, and depressurizes the refrigerant. To inflate. Similar to the first throttle device 35, the second throttle device 36 can be variably controlled in opening, for example, a precise flow control device using an electronic expansion valve, an inexpensive refrigerant flow rate control means such as a capillary tube, etc. It is good to comprise.

In this way, by providing the first inter-refrigerant heat exchanger 33 and the second inter-refrigerant heat exchanger 34, heat exchange is performed between the refrigerant flowing from the gas-liquid separator 31 and the refrigerant flowing to the second connection pipe 38. And the refrigerant can be brought into an appropriate supercooled state. Further, the amount of bypass is controlled by the opening degree of the second expansion device 36 so as to achieve proper supercooling at the primary outlet of the second inter-refrigerant heat exchanger 34.

[

Load side units

40A, 40B]
The load-

side units

40A and 40B are in charge of the cooling load or the heating load in response to the supply of cold or warm heat from the

heat source units

10A and 10B. Each of the

load side units

40A and 40B includes an indoor expansion device 41 and a load side heat exchanger 42, and the indoor expansion device 41 and the load side heat exchanger 42 are connected in series. The indoor throttle device 41 has a function as a pressure reducing valve or an expansion valve, and expands the refrigerant by reducing the pressure. The indoor throttling device 41 may be constituted by a device whose opening degree can be variably controlled, for example, a precise flow rate control device using an electronic expansion valve or an inexpensive refrigerant flow rate control means such as a capillary tube.

The load-side heat exchanger 42 performs heat exchange between a heat medium such as ambient air and water and the refrigerant, condenses and liquefies the refrigerant as a condenser (heat radiator) during heating operation, and an evaporator during cooling operation. The refrigerant is evaporated and gasified. A blower (not shown) for supplying air to the load-side heat exchanger 42 is provided. Further, the load side heat exchanger 42 may perform heat exchange between the refrigerant and a heat medium different from the refrigerant such as water.

In the refrigeration cycle apparatus 1 having the above-described configuration, for example, a control device 50 that controls the operation of the refrigeration cycle apparatus 1 is provided in the heat source side unit 10A. The control device 50 controls the operation of the components of the refrigeration cycle apparatus 1 according to information detected by various sensors and input from the user. For example, the load-

side units

40A and 40B include a temperature sensor 43 that detects the temperature of the refrigerant flowing between the indoor expansion device 41 and the load-side heat exchanger 42, the load-side heat exchanger 42, and the second flow path switch 32. It has a temperature sensor 44 for detecting the temperature of the refrigerant pipe in between. The control device 50 controls the operation of the refrigeration cycle apparatus 1 based on the temperature information detected by the

temperature sensors

43 and 44.

In addition, although illustrated about the case where the control apparatus 50 is mounted in the heat-

source side unit

10A, 10B, you may make it provide in the refrigerant | coolant control unit 30 or the

load side unit

40A, 40B, and it is provided outside as a separate body. It may be provided. Further, the control device 50 may be divided into a plurality according to the function and provided in each of the heat

source side units

10A and 10B, the refrigerant control unit 30, and the

load side units

40A and 40B. In this case, each control device is preferably connected wirelessly or by wire so that communication is possible.

The refrigeration cycle apparatus 1 has a configuration that can be operated in four operation modes by switching the refrigerant flow paths of the first flow path switch 12 and the second flow path switch 32. Specifically, the refrigeration cycle apparatus 1 includes a cooling only operation mode in which all of the

load side units

40A and 40B perform a cooling operation, a heating only operation mode in which all of the

load side units

40A and 40B perform a heating operation, a load A cooling operation or a heating operation can be selected for each of the

side units

40A and 40B, a cooling main operation mode in which the cooling load is larger, a cooling operation or a heating operation can be selected for each of the

load side units

40A and 40B, and the heating load is larger It is a heating main operation mode. Furthermore, the amount of heat is stored in the heat storage tank of the heat storage unit 20 during the heating only operation mode and the heating main operation mode (heat storage heating operation mode).

In particular, frost formation may occur in the heat source side heat exchanger 13 in the heating only operation mode and the heating main operation mode. That is, since the heat source side heat exchanger 13 functions as an evaporator, the heat source side heat exchanger 13 is frosted as the operating time elapses, for example, under conditions where the outside air wet bulb temperature is below 6 degrees. When frost formation occurs, the ventilation resistance of the heat source side heat exchanger 13 increases and the amount of heat exchange decreases, so it is necessary to defrost. Therefore, the refrigeration cycle apparatus 1 further has a defrost operation mode in which defrosting is performed one by one among the plurality of heat

source side units

10A and 10B while continuing the heating operation using the heat storage unit 20. Hereinafter, the heating only operation mode and the defrost operation mode will be described in detail.

[All-heating operation mode (heat storage heating operation mode)]
FIG. 2 is a refrigerant circuit diagram showing a refrigerant flow when the refrigeration cycle apparatus of FIG. 1 is in the heating only operation mode. The operation of the refrigeration cycle apparatus 1 when in the heating only operation mode will be described with reference to FIG. At this time, the control device 50 switches the flow path so that the refrigerant flow path in which the heating only operation is performed. That is, in the heat

source side units

10A and 10B, the first flow path switching unit 12 is switched so that the refrigerant discharged from the compressor 11 flows to the heat storage unit 20 side. Further, the first on-off valve 17 is controlled to be opened and the second on-off valve 19 is controlled to be closed. Further, in the heat storage unit 20, the heat storage flow path switch 21 is switched so that the refrigerant flowing from the heat

source side units

10A and 10B flows to the heat storage heat exchanger 22B. Further, in the second flow path switch 32 of the refrigerant control unit 30, the first on-off

valves

32a and 32b are opened, and the second on-off

valves

32c and 32d are controlled to be closed.

First, the low-temperature / low-pressure refrigerant is compressed in the compressor 11 and discharged as a high-temperature / high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 passes through the first flow path switch 12 and flows into the high-

pressure pipes

3A and 3B via the check valve 15c. The high-temperature and high-pressure gas refrigerant that has flowed out from each of the

heat source units

10A and 10B joins through the high-pressure joining pipe 3C and then flows to the heat storage unit 20 side.

In the heat storage unit 20, a part of the high-temperature / high-pressure gas refrigerant flows to the refrigerant control unit 30, and a part flows into the heat storage heat exchanger 22 B via the heat storage flow path switch 21. The high-temperature and high-pressure refrigerant that has flowed into the heat storage heat exchanger 22B exchanges heat with the medium stored in the heat storage tank 22A by the heat storage heat exchanger 22B, and becomes a low-temperature and high-pressure refrigerant. At this time, heat is stored in the heat storage tank 22A. Thereafter, the refrigerant flowing out of the heat storage heat exchanger 22B is decompressed by the expansion device 23b, and merges with the refrigerant returned from the refrigerant control unit 30.

On the other hand, the high-temperature and high-pressure gas refrigerant flowing into the refrigerant control unit 30 side flows into the load-

side units

40A and 40B via the gas-liquid separator 31 and the first on-off

valves

32a and 32b. The gas refrigerant that has flowed into each of the load-

side units

40A and 40B flows into the load-side heat exchanger 42 that functions as a condenser, and is condensed and liquefied by exchanging heat with the surrounding air. At this time, the air-conditioning target space such as the room is heated by the refrigerant radiating heat to the surroundings. Thereafter, the liquid refrigerant flowing out from the load side heat exchanger 42 is depressurized by the indoor expansion device 41 and flows out from the

load side units

40A and 40B.

The liquid refrigerant decompressed by the indoor expansion device 41 flows through the

liquid pipes

6A and 6B and flows into the refrigerant control unit 30. The liquid refrigerant flowing into the refrigerant control unit 30 reaches the low pressure pipe 2E via the second expansion device 36, the second inter-refrigerant heat exchanger 34, the first inter-refrigerant heat exchanger 33, and the second connection pipe 38. The refrigerant flowing through the low pressure pipe 2E returns into the heat storage unit 20, joins the refrigerant that has flowed out of the heat storage heat exchanger 22B, and flows to the low pressure pipe 2D side. The refrigerant flowing through the low-pressure pipe 2D is branched into the low-

pressure pipes

2A and 2B in the low-pressure joining pipe 2C and flows into the heat

source side units

10A and 10B.

The refrigerant that has flowed into the heat

source side units

10A and 10B reaches the heat source side heat exchanger 13 via the

check valves

15b and 16b and the first on-off valve 17. In the heat source side heat exchanger 13, the refrigerant exchanges heat with the surrounding air, and the refrigerant evaporates and gasifies. Thereafter, the refrigerant that has flowed out of the heat source side heat exchanger 13 flows into the accumulator 14 via the first flow path switch 12. The refrigerant in the accumulator 14 is sucked by the compressor 11 and circulated in the system, so that a refrigeration cycle is established.

[Defrost operation mode]
FIG. 3 is a refrigerant circuit diagram illustrating a refrigerant flow when the refrigeration cycle apparatus of FIG. 1 is in a defrosting operation mode. Based on FIG. 3, the operation | movement operation | movement at the time of the defrost operation mode of the refrigerating-cycle apparatus 1 is demonstrated. In addition, in FIG. 3, the case where the defrost of the heat source side unit 10A side is performed and the normal heating operation mode is continued on the heat source side unit 10B side will be described. At this time, the control device 50 switches the flow path so that the refrigerant flow path in which the above-described defrost operation is performed. That is, in the heat source side unit 10A, the second on-off valve 19 is controlled to be opened and the first on-off valve 17 is closed. Note that, on the heat source side unit 10B side, similarly to the heating only operation mode described above, control is performed so that the first on-off valve 17 is opened and the second on-off valve 19 is closed. Further, in the heat storage unit 20, the heat storage flow path switching unit 21 is switched so that the refrigerant flowing in from the low pressure pipe 2E flows to the heat storage heat exchanger 22B. In addition, as for the 2nd flow-path switching device 32 of the refrigerant | coolant control unit 30, 1st on-off

valve

32a, 32b will be in an open state, and 2nd on-off

valve

32c, 32d will be in a closed state similarly to the heating only operation mode mentioned above. To be controlled.

First, in the heat source side unit 10A, the low-temperature / low-pressure refrigerant is compressed by the compressor 11 and discharged as a high-temperature / high-pressure gas refrigerant. A part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows to the second on-off valve 19 side, a part thereof passes through the first flow path switch 12, and the high-pressure pipe 3A via the check valve 15c. To flow. And the refrigerant | coolant which flowed to the 2nd on-off valve 19 is restrict | squeezed to low pressure, Then, it flows in into the heat source side heat exchanger 13. FIG. At this time, heat exchange with frost in the heat source side heat exchanger 13 is performed, and defrost is performed (hot gas defrost). The refrigerant that has passed through the heat source side heat exchanger 13 passes through the check valve 16 c and the junction A, and flows into the accumulator 14 through the first flow path switch 12.

On the other hand, in the heat source side unit 10B, similarly to the heating operation mode described above, the low-temperature / low-pressure refrigerant is compressed by the compressor 11 to become a high-temperature / high-pressure gas refrigerant, and the high-temperature / high-pressure gas refrigerant is reversed. It flows into the high pressure merging pipe 3C through the stop valve 15c and the high pressure pipe 3B. In the high-pressure merging pipe 3C, the high-temperature and high-pressure gas refrigerant flowing out from each of the heat

source side units

10A and 10B is merged and flows into the refrigerant control unit 30 via the high-pressure pipe 3D.

The high-temperature and high-pressure gas refrigerant that has flowed into the refrigerant control unit 30 side flows into the load-

side units

40A and 40B via the gas-liquid separator 31 and the first on-off

valves

32a and 32b. The gas refrigerant that has flowed into each of the load-

side units

load side units

40A and 40B.

liquid pipes

6A and 6B and flows into the refrigerant control unit 30. The liquid refrigerant flowing into the refrigerant control unit 30 reaches the low pressure pipe 2E via the second expansion device 36, the second inter-refrigerant heat exchanger 34, the first inter-refrigerant heat exchanger 33, and the second connection pipe 38. The refrigerant flowing through the low pressure pipe 2E returns into the heat storage unit 20. A part of the refrigerant flowing into the heat storage unit 20 flows to the heat storage heat exchanger 22B in the refrigerant branch part 23, and a part flows to the low pressure pipe 2D. The refrigerant that has flowed to the heat storage heat exchanger 22B exchanges heat with the medium in the heat storage tank 22A that has reached the refrigerant saturation temperature or higher in the heating operation mode, and is evaporated and gasified. Then, the evaporated and gasified refrigerant reaches the heat source unit selection unit 24 via the heat storage flow path switch 21. And a refrigerant | coolant flows in into 10 A of heat source side units which are defrosting via the heat source unit selection part 24 and the piping 5A.

In the heat source side unit 10A, the refrigerant that has flowed into the heat source side unit 10A from the pipe 5A merges with the refrigerant that has flowed out of the heat source side heat exchanger 13 that has been defrosted, and flows into the accumulator 14. Then, the compressor 11 sucks the refrigerant in the accumulator 14.

On the other hand, the refrigerant that has flowed into the low pressure pipe 2D flows into the heat source side unit 10B through the low pressure joining pipe 2C and the low pressure pipe 2B. In the low-pressure merging pipe 2C, since the first on-off valve 17 of the heat source side unit 10A is closed, the refrigerant flows into the refrigerant flow path leading to the low pressure pipe 2A and the

check valves

15b and 16b on the heat source side unit 10A side. Not flowing. The refrigerant flowing into the heat source side unit 10B reaches the heat source side heat exchanger 13 via the

check valves

15b and 16b and the first on-off valve 17. In the heat source side heat exchanger 13, the refrigerant exchanges heat with the surrounding air, and the refrigerant evaporates and gasifies. Thereafter, the refrigerant that has flowed out of the heat source side heat exchanger 13 flows into the accumulator 14 via the first flow path switch 12.

As described above, when the heat source side heat exchanger 13 of the heat source side unit 10A performs defrosting, the load side heat exchanger 42 does not function as an evaporator. Therefore, the heat source side unit 10A is configured such that the refrigerant flowing through the heat storage heat exchanger 22B flows into the heat source side unit 10A so that the heat storage heat exchanger 22B functions as an evaporator. The refrigerant that has flowed out of the heat source side heat exchanger 13 is in a wet state (saturated liquid depending on the operating state), and the refrigerant that has exchanged heat in the heat storage heat exchanger 22B is a refrigerant with a superheat degree. These refrigerants merge at the junction A and flow into the accumulator 14. The refrigerant in the accumulator 14 is sucked by the compressor 11 and circulated in the system, so that a refrigeration cycle is established on the heat source side unit 10A side. On the other hand, in the heat source side unit 10B, the heating operation is continued, and a refrigeration cycle is established using the load side heat exchanger 42 as a condenser.

That is, during the defrosting operation, in the refrigeration cycle apparatus 1 having the plurality of heat

source side units

10A and 10B, the heat source side heat exchanger 13 is used as a condenser while performing hot gas defrosting on the side of one heat source side unit 10A. A refrigeration cycle using the exchanger 22B as an evaporator is configured. At the same time, on the other heat source side unit 10B side, a refrigeration cycle is configured with the load side heat exchanger 42 as a condenser and the heat source side heat exchanger 13 as an evaporator, and the heating operation is continued.

Especially, since the amount of heat is used for defrosting during defrosting, the amount of heat required by the load-side heat exchanger 42 may be insufficient. When the maximum frequency during heating operation is determined below the operable frequency of the compressor 11 due to constraints such as operating efficiency, the frequency of the compressor 11 is increased so as to suppress the decrease in capacity only in the defrost mode. Thereby, the fall of heating capability can be suppressed. FIG. 5 is a graph showing an example of control of the operating frequency of the compressor in the refrigeration cycle apparatus of FIG. As shown in FIG. 5, for example, when the maximum frequency during the heating operation is Fmax1, a decrease in heating capacity can be suppressed by setting Fmax2 (> Fmax1) after time t1 when the defrost operation mode is started.

The operation of each component during the above-described defrost operation is controlled by the control device 50. The control device 50 performs control so that hot gas defrosting is performed one by one during the defrosting operation. FIG. 4 is a flowchart showing an operation example of the heat source unit selection unit 24 at the time of the defrost operation of FIG. 3, and an operation example at the time of the defrost operation will be described with reference to FIG. First, when the refrigeration cycle apparatus 1 is operating in the heating operation mode (see FIG. 2), it is determined whether or not the defrost operation mode is performed in the control device 50 (step ST1). The determination as to whether or not to perform the defrost operation can be made by using a known technique such as determination based on the temperature of the heat source side heat exchanger 13 in each of the heat

source side units

10A and 10B. If it is determined that defrost operation is necessary, it is determined which of the

heat source units

10A and 10B needs defrost (step ST2).

When it is determined that the defrost is necessary for the heat source side unit 10A, the first on-off valve 17 on the heat source side unit 10A side is closed, and the second on-off valve 19 is opened. Further, in the heat storage unit 20, the heat storage flow path switching device 21 is switched, and the first heat storage side on / off valve 24A side of the heat source unit selection unit 24 is opened (step ST3). In this state, defrosting is performed on the heat source side unit 10A side, and the heating operation is continued on the heat source side unit 10B side (see FIG. 3). When it is determined that the defrosting of the heat source side unit 10A is completed (step ST4), the first on-off valve 17 on the heat source side unit 10A side is opened, and the second on-off valve 19 is closed. Further, in the heat storage unit 20, the heat storage flow path switching device 21 is switched, and the first heat storage side on-off valve 24A side of the heat source unit selection unit 24 is closed (step ST5). Then, the heating operation mode is resumed (step ST6). The determination of the completion of the defrost in the control device 50 may be determined to be completed when a predetermined time has elapsed since the defrost operation. For example, the temperature of the heat source side heat exchanger 13 in each of the heat

source side units

10A and 10B It is possible to use a known technique such as making a determination according to the above.

On the other hand, when it is determined that the defrost is necessary for the heat source side unit 10B, the first on-off valve 17 on the heat source side unit 10B side is closed, and the second on-off valve 19 is opened. Further, in the heat storage unit 20, the heat storage flow path switching device 21 is switched, and the first heat storage side opening / closing valve 24A side of the heat source unit selection unit 24 is opened (step ST7). In this state, defrosting is performed on the heat source side unit 10B side, and the heating operation is continued on the heat source side unit 10A side (see FIG. 3). When it is determined that the defrosting of the heat source side unit 10A is completed (step ST8), the first on-off valve 17 on the heat source side unit 10A side is opened, and the second on-off valve 19 is closed. Further, in the heat storage unit 20, the heat storage flow path switching device 21 is switched, and the first heat storage side on-off valve 24A side of the heat source unit selection unit 24 is closed (step ST9). Then, the heating operation mode is resumed (step ST10).

According to the above embodiment, in the refrigeration cycle apparatus 1 having the plurality of heat

source side units

10A and 10B, the heat storage heat exchanger 22B is used as an evaporator while performing hot gas defrosting for one heat source side unit 10A during defrost operation. In the other heat source side unit 10B, a refrigeration cycle using the load side heat exchanger 42 as an evaporator is configured, and heating operation is performed while suppressing an increase in size of the heat

source side units

10A and 10B. Defrost operation can be performed while continuing. That is, when the heat storage tank is provided for each heat source unit as in the conventional case, the heat storage tanks for the number of heat source units are required, which increases the unit cost and the installation space. On the other hand, in the refrigeration cycle apparatus 1 shown in FIG. 1, since the plurality of heat

source side units

10A and 10B are connected to one heat storage unit 20 to perform the defrost operation, cost reduction and space saving can be achieved.

Further, in the defrost operation mode, one heat source side unit 10A out of the heat

source side units

10A and 10B is connected to the heat storage unit 20, and the other heat source side unit 10B continues the heating operation one by one. By performing defrosting, it is possible to achieve both the defrosting operation and the heating operation while suppressing the increase in size of the heat

source side units

10A and 10B. That is, in the heating and heat storage operation mode, it is necessary to store heat in the heat storage tank so that the heating capacity can be maintained during the heat storage defrost while performing the heating operation, and the heat

source side units

10A and 10B are air conditioners of the

load side units

40A and 40B. The horsepower that is larger than the horsepower that matches the ability is output. For this reason, if it is going to defrost several heat

source side unit

10A, 10B simultaneously, a large sized heat source machine and a thermal storage tank will be needed, and an installation space will become large or the installation weight will become heavy. On the other hand, by connecting one heat source side unit 10A to the heat storage unit 20 and continuing the heating operation in the other heat source side unit 10B, it is possible to suppress an increase in the size of the heat

source side units

10A and 10B and the heat storage tank 22A. it can.

Moreover, the refrigerant | coolant branch part which is provided between

load side unit

40A, 40B and the thermal storage part 22, and branches the refrigerant | coolant which flowed out from

load side unit

40A, 40B to the thermal storage part 22 side and the heat

source side unit

10A, 10B side 23 is further provided, the heating operation can be continued in the heat source unit 10B while defrosting the heat source unit 10A.

The embodiment of the present invention is not limited to the above embodiment. For example, in the above embodiment, the case where the refrigeration cycle apparatus 1 includes two heat

source side units

10A and 10B, one refrigerant control unit 30, and two

load side units

40A and 40B is illustrated. The number of units is not limited, and each unit may have three or more heat source units and load units. Moreover, in the said embodiment, although illustrated about the case where the refrigeration cycle apparatus 1 is applied to the air conditioning apparatus, it is applicable also to other systems using refrigeration cycles, such as a refrigeration system.

Moreover, in the said embodiment, although illustrated about the case where one heat storage part 22 is installed, you may install multiple units | sets. In this case, the number of the heat storage parts 22 is several heat source side. The number is smaller than that of the

units

10A and 10B. Thereby, defrosting of predetermined heat source side unit 10A can be performed, continuing heating operation, aiming at space saving.

1 Refrigeration cycle apparatus, 2A, 2B, 2D, 2E low pressure pipe, 2C low pressure merge pipe, 3A, 3B, 3D high pressure pipe, 3C high pressure merge pipe, 5A, 5B pipe, 6A, 6B liquid pipe, 7A, 7B gas pipe, 10A, 10B heat source side unit, 11 compressor, 12 flow path switch, 13 heat source side heat exchanger, 13A blower, 14 accumulator, 15a-15d check valve, 16a-16d check valve, 17 first open / close valve, 18 bypass piping, 19 second on-off valve, 20 heat storage unit, 21 heat storage flow path switch, 22 heat storage section, 22A heat storage tank, 22B heat storage heat exchanger, 23 refrigerant branch section, 23a check valve, 23b throttle device, 24 Heat source unit selector, 24A, first heat storage side on / off valve, 24B, second heat storage side on / off valve, 30 refrigerant control unit, 31 gas-liquid separator 32 2nd flow path switcher, 32a, 32b 1st on-off valve, 32c, 32d 2nd on-off valve, 33 1st inter-refrigerant heat exchanger, 34 1st inter-refrigerant heat exchanger, 35 1st throttling device, 36th 2 throttle devices, 37 first connection piping, 38 second connection piping, 40A, 40B load side unit, 41 throttle device, 42 load side heat exchanger, 43, 44 temperature sensor, 50 control device, A junction.

Claims

A plurality of heat source side units in which a compressor, a flow path switch, and a heat source side heat exchanger are sequentially connected; and a load side unit having a load side heat exchanger connected to the plurality of heat source side units. Comprising a refrigerant circuit in which a refrigerant circulates between the plurality of heat source side units and the load side unit,
Each of the heat source side units is
A first on-off valve provided on the refrigerant flow path from the load side unit to the heat source side heat exchanger;
A bypass pipe connecting the discharge side of the compressor and the heat source side heat exchanger;
A second on-off valve provided on the bypass pipe for controlling inflow of refrigerant from the compressor to the heat source side heat exchanger,
A heat storage unit that is provided between the plurality of heat source side units and the load side unit and exchanges heat with a refrigerant that flows between the plurality of heat source side units and the load side unit;
A heat storage switch that switches between a flow path through which the refrigerant flows from the plurality of heat source units to the heat storage section and a flow path from which the refrigerant flows into the heat storage section from the load side unit;
In the heat storage switching device, the heat source side unit selecting unit that selects the heat source side unit that causes the refrigerant that has flowed out of the heat storage unit to flow in when the channel is switched to the flow path in which the refrigerant flows from the load side unit to the heat storage unit. When,
A refrigeration cycle apparatus comprising: a control device that controls the first open / close valve to be closed and the second open / close valve to be opened in the heat source side unit selected by the heat source side unit selector. .
The refrigerant branching portion provided between the load side unit and the heat storage unit and further branching the refrigerant flowing out from the load side unit into the heat storage unit side and the heat source side unit side. The refrigeration cycle apparatus described.
The control device controls to perform a heating operation mode and a defrost operation mode, and in the defrost operation mode, the heat source side unit that performs defrosting is selected in the heat source side unit selection unit, The control according to claim 2, wherein the first open / close valve is controlled to be closed, the second open / close valve is controlled to be opened, and the other heat source side unit is controlled to perform heating operation. Refrigeration cycle equipment.
The refrigeration cycle apparatus according to claim 3, wherein the control device selects the heat source side units to be defrosted one by one.
The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein the heat storage units are installed by a number smaller than the number of the plurality of heat source side units.
The refrigeration cycle apparatus according to claim 5, wherein one heat storage unit is installed.
The air conditioning apparatus according to any one of claims 1 to 6, wherein the heat storage unit is independent as an apparatus separate from the plurality of heat source side units.
The air conditioning apparatus according to any one of claims 1 to 6, wherein the heat storage section is built in any of the plurality of heat source side units.