A multi-connected heat pump system

Abstract

The present application relates to a kind of multi-supply heat pump systems, the system is provided with N parallel three-way valves at the exhaust port of compressor, the exhaust end of each three-way valve is connected with the return port of compressor, and the working end of each three-way valve is connected with a heat exchanger, wherein, the second heat exchanger to the Nth heat exchanger is connected with the first heat exchanger through a on-off valve after connecting electronic expansion valve, to form refrigerant circulation loop, and further comprising controller electrically connected and / or communication connection with above-mentioned each valve.The system realizes single or multiple working mode by the opening and closing of each valve controlled by controller, when there is idle heat exchanger in the system, idle heat exchanger is always placed in low pressure state, and then most of the refrigerant in the system participates in heating or heating cycle, solve the problem that the refrigerant charging amount of system circulation work is reduced due to the existence of idle heat exchanger, the heat release amount of condenser to the outside world is reduced, the heat absorption amount of evaporator from the outside world is reduced, so that the overall refrigeration or heating effect of system is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat pump systems, in particular to a multi-coupling heat pump system. BACKGROUND

[0002] The triple-coupling heat pump system is a high-efficiency and integrated complex heat pump system, which can provide air conditioning, floor heating and / or hot water at the same time, and meet the diversified needs of users. Secondly, through heat recovery technology, it realizes efficient use of energy, which meets the development trend of energy saving and emission reduction, green and low carbon in today's society, and is more and more favored by places such as family residence, hotel, hospital and office building.

[0003] The heat recovery technology of the triple-coupling heat pump system has made some progress, which can recover heat energy and cold energy and convert them into domestic hot water while providing refrigeration and heating, realizing efficient use of energy. However, there is still a problem that the cooperative control of the refrigerant flow path of each function is not good, which wastes part of the recoverable energy and cannot make the energy utilization rate of the system optimal.

[0004] The control of the refrigerant flow path in the triple-coupling heat pump system often has the following problems:

[0005] 1) When there is an idle heat exchanger in the system, the flow direction of the refrigerant cannot be controlled;

[0006] 2) There are multiple electronic expansion valves in the system, which makes the refrigerant in the system excessively throttled, increases the content of flash steam, and thus reduces the heat exchange efficiency of the evaporator.

[0007] At the same time, due to the need of multi-functional setting of the system, a high-pressure liquid storage tank is needed to store excess refrigerant in the system, which increases the pressure loss while increasing the pressure container, reducing the reliability of the system. SUMMARY

[0008] Therefore, the purpose of the present application is to provide a multi-coupling heat pump system to solve the technical problem that the existing triple-coupling heat pump system cannot make all the refrigerants in the system participate in the circulation when there is an idle heat exchanger in the system.

[0009] A multi-coupling heat pump system, comprising:

[0010] a compressor provided with an exhaust port A and a return port B;

[0011] N three-way valves arranged in parallel, the i th three-way valve is provided with an inlet end Ci, an exhaust end Di and a working end Ei, wherein i∈(1, N), N≥3; the inlet end of each three-way valve is connected with the exhaust port A, and the exhaust end is connected with the return port B;

[0012] N heat exchangers, the i-th heat exchanger is provided with a first port Fi and a second port Gi; the first port of each heat exchanger is connected to the working end of each three-way valve one by one and separately;

[0013] N-1 electronic expansion valves, the j-th electronic expansion valve is provided with a high-pressure side Hj and a low-pressure side Oj, wherein j∈(2, N); the high-pressure side of each electronic expansion valve is connected to the second port of the 2nd heat exchanger to the Nth heat exchanger one by one and separately; the low-pressure side of each electronic expansion valve is connected to the second port of the 1st heat exchanger;

[0014] A controller, which is electrically connected and / or communicatively connected to each three-way valve and each electronic expansion valve, and controls the opening and closing of each three-way valve and each electronic expansion valve according to the working mode of the system.

[0015] Further, a shutoff valve is further included, one end of the shutoff valve is connected to the second port G1 of the first heat exchanger, and the other end is connected to the low-pressure side of each electronic expansion valve; the shutoff valve is electrically connected and / or communicatively connected to the controller.

[0016] Further, a plurality of flow control valves are further included, the flow control valves are set according to the total heat recovery mode of the multi-connected heat pump system, so that the high-pressure side of the electronic expansion valve connected to the heat exchanger acting as an evaporator is connected to the low-pressure side of the electronic expansion valve connected to the heat exchanger acting as a condenser one by one and separately in the total heat recovery mode of the multi-connected heat pump system, and each flow control valve is electrically connected and / or communicatively connected to the controller.

[0017] Further, N=3, i.e. the multi-connected heat pump system is a three-connected heat pump system, and the three-connected heat pump system includes:

[0018] A compressor;

[0019] A first three-way valve, a second three-way valve and a third three-way valve arranged in parallel;

[0020] A first heat exchanger connected to the first three-way valve, a second heat exchanger connected to the second three-way valve and a third heat exchanger connected to the third three-way valve;

[0021] A second electronic expansion valve connected to the second heat exchanger and a second electronic expansion valve connected to the third heat exchanger;

[0022] A shutoff valve, one end of which is connected to the first heat exchanger, and the other end of which is connected to the second electronic expansion valve and the third electronic expansion valve;

[0023] A controller electrically connected and / or communicatively connected to each valve.

[0024] Further, the first heat exchanger is a fin heat exchanger, the second heat exchanger is a hot water jacket, the third heat exchanger is a cold and warm jacket, the on-off valve is an electromagnetic two-way valve, and the controller realizes the full heat recovery mode in the following way:

[0025] The first three-way valve and the third three-way valve are controlled to be powered off, and the second three-way valve is controlled to be powered on.

[0026] The on-off valve is controlled to be closed, the second electronic expansion valve and the third electronic expansion valve are controlled to be opened, the second heat exchanger is used as a condenser, the third heat exchanger is used as an evaporator, and the first heat exchanger is idle.

[0027] Further, a flow control valve is further included, one end of the flow control valve is connected with the low-pressure side of the second electronic expansion valve, the other end of the flow control valve is connected with the high-pressure side of the third electronic expansion valve, and the controller realizes the full heat recovery mode and avoids secondary throttling in the following way:

[0028] The first three-way valve and the third three-way valve are controlled to be powered off, and the second three-way valve is controlled to be powered on.

[0029] The third electronic expansion valve and the on-off valve are controlled to be closed, the second electronic expansion valve and the flow control valve are controlled to be opened, the second heat exchanger is used as a condenser, the third heat exchanger is used as an evaporator, and the first heat exchanger is idle.

[0030] Further, N=4, that is, the multi-connection heat pump system is a four-connection heat pump system, and the four-connection heat pump system includes:

[0031] A compressor;

[0032] Four first three-way valves, second three-way valves, third three-way valves and fourth three-way valves arranged in parallel;

[0033] A first heat exchanger connected with the first three-way valve, a second heat exchanger connected with the second three-way valve, a third heat exchanger connected with the third three-way valve, and a fourth heat exchanger connected with the fourth three-way valve;

[0034] A second electronic expansion valve connected with the second heat exchanger, a third electronic expansion valve connected with the third heat exchanger, and a fourth electronic expansion valve connected with the fourth heat exchanger;

[0035] An on-off valve, one end of the on-off valve is connected with the first heat exchanger, and the other end of the on-off valve is connected with the second electronic expansion valve, the third electronic expansion valve and the fourth electronic expansion valve;

[0036] A controller electrically connected and / or communicatively connected with the above valves.

[0037] Further, the first heat exchanger is a fin heat exchanger, the second heat exchanger is a hot water jacket, the third heat exchanger is a cold and warm jacket, and the fourth heat exchanger is a floor heating jacket; the on-off valve is an electromagnetic two-way valve, and the controller realizes the heat recovery mode of hot water production + refrigeration in the following manner:

[0038] The first three-way valve, the third three-way valve, and the fourth three-way valve are controlled to be powered off, and the second three-way valve is controlled to be powered on.

[0039] The fourth electronic expansion valve and the on-off valve are controlled to be closed, the second electronic expansion valve and the third electronic expansion valve are controlled to be opened, the second heat exchanger is used as a condenser, the third heat exchanger is used as an evaporator, and the first heat exchanger and the fourth heat exchanger are idle.

[0040] The controller realizes the heat recovery mode of heating + hot water production + refrigeration in the following manner:

[0041] The first three-way valve and the third three-way valve are controlled to be powered off, and the second three-way valve and the fourth three-way valve are controlled to be powered on.

[0042] The on-off valve is controlled to be closed, the second electronic expansion valve, the third electronic expansion valve, and the fourth electronic expansion valve are controlled to be opened, the second heat exchanger and the fourth heat exchanger are used as condensers, the third heat exchanger is used as an evaporator, and the first heat exchanger is idle.

[0043] Further, the first flow control valve and the second flow control valve are further included, one end of the first flow control valve is connected with the low-pressure side of the second electronic expansion valve, the other end of the first flow control valve is connected with the high-pressure side of the third electronic expansion valve, one end of the second flow control valve is connected with the low-pressure side of the fourth electronic expansion valve, the other end of the second flow control valve is connected with the high-pressure side of the third electronic expansion valve, and the controller realizes the heat recovery mode of hot water production + refrigeration and avoids secondary throttling in the following manner:

[0044] The first three-way valve, the third three-way valve, and the fourth three-way valve are controlled to be powered off, and the second three-way valve is controlled to be powered on.

[0045] The third electronic expansion valve, the fourth electronic expansion valve, and the on-off valve are controlled to be closed, the second electronic expansion valve and the first flow control valve are controlled to be opened, the second heat exchanger is used as a condenser, the third heat exchanger is used as an evaporator, and the first heat exchanger and the fourth heat exchanger are idle.

[0046] The controller realizes the heat recovery mode of heating + hot water production + refrigeration and avoids secondary throttling in the following manner:

[0047] The first three-way valve and the third three-way valve are controlled to be powered off, and the second three-way valve and the fourth three-way valve are controlled to be powered on.

[0048] Controlling the third electronic expansion valve, on-off valve to close; the second electronic expansion valve, the fourth electronic expansion valve, the first flow control valve 61, the second flow valve to open; make the second heat exchanger, the fourth heat exchanger as condenser, the third heat exchanger as evaporator, the first heat exchanger idle.

[0049] Compared with the prior art, the present application has the following beneficial technical effects:

[0050] 1) The system sets up N parallel three-way valves at the exhaust port of the compressor, the exhaust end of each three-way valve is connected with the return air port of the compressor, the working end of each three-way valve is connected with a heat exchanger, the second heat exchanger to the Nth heat exchanger is connected with the first heat exchanger through an electronic expansion valve, forming a structure setting mode of refrigerant circulation loop, and the flow direction of the system refrigerant can be controlled by the controller controlling the opening and closing of each three-way valve and each electronic expansion valve, so that the system does not exist in series and shunt, and then the control of multiple working modes is realized; based on the same structure setting, when there is an idle heat exchanger, the controller controls the opening and closing of each electronic expansion valve, so that the idle heat exchanger presents a low pressure state in the system, so that the refrigerant in the non-idle heat exchanger can be matched according to the single system charging amount, covering the working conditions, so that the refrigerant in each mode participates in the working cycle, improving the efficiency of the system; based on the same structure setting, when the first heat exchanger as evaporator needs to be defrosted, the heat exchanger for heating or the heat exchanger for heating water can be selected to complete the refrigerant circulation loop, and the system has fault tolerance, further improving the stability of the system defrosting;

[0051] 2) The system sets a flow control valve between the first heat exchanger as evaporator and the connecting pipeline of each electronic expansion valve, and by closing the flow control valve, the system has a full heat recovery mode, and the user with useful cold demand can provide free cold when running heating or hot water;

[0052] 3) The system sets a flow control valve at the low pressure side of the electronic expansion valve connected to the second heat exchanger to the Nth heat exchanger, which is connected to the high pressure side of the electronic expansion valve corresponding to the heat exchanger with cold release, so that the system can flow out of the heat exchanger in the full heat recovery mode, and only needs to pass through the throttling of an electronic expansion valve to flow into the heat exchanger as evaporator, without passing through the low pressure side of an electronic expansion valve, so that the system does not exist in the transition throttling, and solves the series problems of reducing the refrigeration / heating effect and reducing the system efficiency caused by excessive throttling in the existing multi-supply system.

[0053] In order to better understand and implement, the present application is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 The system structure schematic diagram of embodiment 1 of the present application;

[0055] Figure 2 A refrigerant flow direction schematic diagram for the heating mode of the embodiment 1 of the present application;

[0056] Figure 3 A refrigerant flow direction schematic diagram for the hot water mode of the embodiment 1 of the present application;

[0057] Figure 4 A refrigerant flow direction schematic diagram for the heating or defrosting mode of the embodiment 1 of the present application;

[0058] Figure 5 A refrigerant flow direction schematic diagram for the hot water defrosting mode of the embodiment 1 of the present application;

[0059] Figure 6 A refrigerant flow direction schematic diagram for the total heat recovery mode of the embodiment 1 of the present application;

[0060] Figure 7 A refrigerant flow direction schematic diagram for the heating + heating mode of the embodiment 2 of the present application;

[0061] Figure 8 A refrigerant flow direction schematic diagram for the hot water + heating mode of the embodiment 2 of the present application;

[0062] Figure 9 A refrigerant flow direction schematic diagram for the heating + hot water mode of the embodiment 2 of the present application;

[0063] Figure 10 A refrigerant flow direction schematic diagram for the hot water + heating total heat recovery mode of the embodiment 2 of the present application;

[0064] Figure 11 A refrigerant flow direction schematic diagram for the hot water total heat recovery mode of the embodiment 2 of the present application. DETAILED DESCRIPTION

[0065] The technical solutions of the present application will be described in detail below with the drawings of the embodiments of the present application.

[0066] To solve the problem that in the existing triple supply heat pump system, when there is an idle heat exchanger in different working modes, part of the refrigerant is left in the idle heat exchanger, which causes the system refrigerant to not be able to participate in the refrigerant circulation, resulting in the decrease of the heat release of the condenser to the outside and the decrease of the heat absorption of the evaporator from the outside, thereby reducing the overall refrigeration or heating effect of the system.

[0067] According to the research design, the application provides a multi-supply heat pump system, the system is provided with N parallel three-way valves at the exhaust port of the compressor, the exhaust end of each three-way valve is connected with the gas return port of the compressor, and the working end of each three-way valve is connected with a heat exchanger, wherein the second heat exchanger to the Nth heat exchanger is connected with the first heat exchanger through a on-off valve after being connected with an electronic expansion valve, to form a refrigerant circulation loop, and the system further comprises a controller electrically connected and / or communicatively connected with each three-way valve, each electronic expansion valve and the on-off valve. The system controls the opening and closing of each three-way valve, each electronic expansion valve and the on-off valve through the controller to realize single or multiple working modes, when there is an idle heat exchanger in the system, the idle heat exchanger is always in a low pressure state by using the refrigerant flow characteristics, and then the refrigerant in the idle heat exchanger flows from the heat exchanger to the compressor gas return port until the pressure in the heat exchanger reaches balance, so that most of the refrigerant in the system participates in heating or heating cycle, solves the problem that the refrigerant charging amount of the system cycle is reduced due to the existence of the idle heat exchanger, the heat release amount of the condenser to the outside is reduced, the heat absorption amount of the evaporator from the outside is reduced, and the overall refrigeration or heating effect of the system is reduced. At the same time, the setting mode can realize full heat recovery in combination with the working mode control; at the same time, additional pressure vessels can be avoided in the system, and the cost of the system is reduced.

[0068] The heat exchanger can be a plate heat exchanger, a double-pipe heat exchanger, a shell-and-tube heat exchanger, etc., and the application does not make any limitation, for example, when a heat exchanger without liquid storage function is used, a high-pressure liquid storage tank can be added.

[0069] Further, to avoid the problem of multiple throttling of the multi-supply heat pump system proposed by the application in the full heat recovery working mode, a refrigerant connection pipeline is arranged between the low pressure side of the electronic expansion valve connected with the heat exchanger serving as the condenser and the high pressure side of the electronic expansion valve connected with the heat exchanger serving as the evaporator, a flow control valve is arranged on the refrigerant connection pipeline, each flow control valve is electrically connected and / or communicatively connected with the controller, and the opening and closing of each flow control valve is controlled by the controller to realize that the refrigerant flowing out of the heat exchanger only experiences throttling of the electronic expansion valve once in each full heat recovery working mode.

[0070] The on-off valve and the flow control valve can be a ball valve, an electromagnetic flow valve, an electromagnetic two-way valve, a pressure reduction and load reduction valve, a stop valve, a butterfly check valve, etc., and the application does not make any limitation, as long as it has the flow control function of fluid.

[0071] Further, to effectively separate the gas and liquid in the refrigerant entering the compressor gas return port, prevent liquid compression of the compressor and improve the operation stability of the system, a gas-liquid separator is arranged between the connection pipeline between the gas return port of the compressor and the exhaust end of each three-way valve in the above multi-supply heat pump system, the gas outlet of the gas-liquid separator is connected with the gas return port of the compressor, and the gas inlet of the gas-liquid separator is connected with the exhaust end of each three-way valve.

[0072] Specifically, the multi-coupling heat pump system comprises:

[0073] a compressor, provided with an exhaust port A and a return port B;

[0074] N three-way valves, the i three-way valve is provided with an intake end Ci, an exhaust end Di and a working end Ei, wherein i∈(1, N), N≥3; the intake end of each three-way valve is connected with the exhaust port A, and the exhaust end is connected with the return port B;

[0075] N heat exchangers, the i heat exchanger is provided with a first port Fi and a second port Gi; the first port of each heat exchanger is connected with the working end of each three-way valve one by one;

[0076] N-1 electronic expansion valves, the j electronic expansion valve is provided with a high pressure side Hj and a low pressure side Oj, wherein j∈(2, N); the high pressure side of each electronic expansion valve is connected with the second port of the second heat exchanger to the N heat exchanger one by one,

[0077] a on-off valve, one end of which is connected with the second port G1 of the first heat exchanger, and the other end is connected with the low pressure side of each electronic expansion valve;

[0078] a controller, electrically connected and / or communicatively connected with each three-way valve, each electronic expansion valve and the on-off valve, and controls the opening and closing of each three-way valve, each electronic expansion valve and the on-off valve according to the working mode of the system.

[0079] Further comprising several flow control valves, the k flow control valve is provided with a low pressure connection port Pk and a high pressure connection port Qk, wherein the low pressure connection port Pk is connected with the low pressure side of an electronic expansion valve, and the high pressure connection port Qk is connected with the high pressure side of another electronic expansion valve; in the full heat recovery mode, the high pressure side of the electronic expansion valve connected with the heat exchanger as evaporator is connected with the low pressure side of the electronic expansion valve connected with the heat exchanger as condenser one by one, and each flow control valve is electrically connected and / or communicatively connected with the controller. This setting can avoid multiple throttling of the multi-coupling heat pump system in each full heat recovery working mode.

[0080] Further comprising a gas-liquid separator, provided with an intake port R and an exhaust port S; the intake port R is connected with the exhaust end D of each three-way valve, and the exhaust port S is connected with the return port B of the compressor.

[0081] Embodiment 1

[0082] Please refer to Figure 1The embodiment is a triple supply heat pump system, i.e. N=3, which comprises a compressor 10, three parallelly arranged first, second and third three-way valves 21, 22 and 23, a first heat exchanger 31 connected with the first three-way valve 21, a second heat exchanger 32 connected with the second three-way valve 22, a third heat exchanger 33 connected with the third three-way valve 23, a second electronic expansion valve 42 connected with the second heat exchanger 32, a third electronic expansion valve 43 connected with the third heat exchanger 33, a on-off valve 50 connected with the first heat exchanger 31, first and second flow control valves 61 and 62 connected with the high and low pressure sides of the second and third electronic expansion valves 42 and 43, a gas-liquid separator 70, and a controller.

[0083] The specific connection and arrangement of the triple supply heat pump system is as follows.

[0084] The first three-way valve 21 has its gas inlet end C1 connected with the exhaust port A of the compressor 10; the second three-way valve 22 has its gas inlet end C2 connected with the exhaust port A; and the third three-way valve 23 has its gas inlet end C3 connected with the exhaust port A.

[0085] The first heat exchanger 31 has its first port F1 connected with the working end E1 of the first three-way valve 21; the second heat exchanger 32 has its first port F2 connected with the working end E2 of the second three-way valve 22; and the third heat exchanger 33 has its first port F3 connected with the working end E3 of the third three-way valve 23.

[0086] The second electronic expansion valve 42 has its high pressure side H2 connected with the second port G2 of the second heat exchanger 32; and the third electronic expansion valve 43 has its high pressure side H3 connected with the second port G3 of the third heat exchanger 33.

[0087] The on-off valve 50 has one end connected with the second port G1 of the first heat exchanger 31 and the other end connected with the low pressure sides O2 and O3 of the second and third electronic expansion valves 42 and 43 respectively.

[0088] The first flow control valve 61 has its low pressure connection port P1 connected with the low pressure side O2 of the second electronic expansion valve 42 and its high pressure connection port Q1 connected with the high pressure side H3 of the third electronic expansion valve 43; and the second flow control valve 62 has its high pressure connection port Q2 connected with the high pressure side H2 of the second electronic expansion valve 42 and its low pressure connection port P2 connected with the low pressure side O3 of the third electronic expansion valve 43.

[0089] The gas-liquid separator 70 has its gas inlets R connected with the exhaust ends D1, D2 and D3 of the first, second and third three-way valves 21, 22 and 23 respectively and its gas outlet S connected with the gas return port B of the compressor 10.

[0090] In the embodiment, the first heat exchanger 31 is a fin heat exchanger, the second heat exchanger 32 is a hot water jacket, the third heat exchanger 33 is a cold and warm jacket, the on-off valve 50 and the first flow control valve 61 are electromagnetic two-way valves. Due to the full heat recovery mode without heating and cold water production, the second flow control valve 62 is idle, i.e. always in the closed state, and can be removed.

[0091] Based on the above settings, please refer to Figure 2 In the single heating mode, the controller realizes that the refrigerant in the system participates in the heating cycle by the following control:

[0092] SA1 controls the first three-way valve 21 and the second three-way valve 22 to be de-energized, and the third three-way valve 23 to be energized.

[0093] SA2 controls the second electronic expansion valve 42 and the first flow control valve 61 to be closed; the third electronic expansion valve 43 and the on-off valve 50 to be opened; so that the third heat exchanger 33 works as a condenser, the first heat exchanger 31 works as an evaporator, and the second heat exchanger 32 is idle.

[0094] In this working mode, the circulation loop of the refrigerant is: compressor 10→ third three-way valve 23→ third heat exchanger 33 (cold and warm jacket)→ third electronic expansion valve 43→ on-off valve 50→ first heat exchanger 31 (fin heat exchanger)→ first three-way valve 21→ gas-liquid separator 70→ compressor 10.

[0095] The second heat exchanger 32 (hot water jacket) connects the second three-way valve 22 to the low-pressure side of the gas-liquid separator, so the refrigerant flows from the second heat exchanger 32 (hot water jacket) to the gas-liquid separator until the pressure balance, and the refrigerant in the system participates in the heating cycle.

[0096] Based on the above settings, please refer to Figure 3 In the single heating water mode, the controller realizes that the refrigerant in the system participates in the heating cycle by the following control:

[0097] SC1 controls the first three-way valve 21 and the third three-way valve 23 to be de-energized, and the second three-way valve 22 to be energized.

[0098] SC2 controls the third electronic expansion valve 43 and the first flow control valve 61 to be closed; the second electronic expansion valve 42 and the on-off valve 50 to be opened; so that the second heat exchanger 32 works as a condenser, the first heat exchanger 31 works as an evaporator, and the third heat exchanger 33 is idle.

[0099] In this working mode, the circulation loop of the refrigerant is: compressor 10→ second three-way valve 22→ second heat exchanger 32 (hot water jacket)→ second electronic expansion valve 42→ on-off valve 50→ first heat exchanger 31 (fin heat exchanger)→ first three-way valve 21→ gas-liquid separator 70→ compressor 10.

[0100] Third heat exchanger 33 (cold and warm sleeve) to the third three-way valve 23 to the gas-liquid separator for low pressure side, so that the refrigerant from the third heat exchanger 33 (cold and warm sleeve) to the gas-liquid separator until the pressure balance, the system refrigerant participate in hot water circulation.

[0101] Based on the above settings, please refer to Figure 4 , the controller in single refrigeration or defrost mode, the following control to achieve single refrigeration mode, the system refrigerant participate in heating cycle:

[0102] SD1 control second three-way valve 22, the third three-way valve 23 power off, the first three-way valve 21 power on;

[0103] SD2 control second electronic expansion valve 42, the first flow control valve 61 closed; the third electronic expansion valve 43, on-off valve 50 open; make the first heat exchanger 31 as condenser, the third heat exchanger 33 as evaporator, the second heat exchanger 32 idle.

[0104] This mode, the refrigerant circulation loop is: compressor 10→the first three-way valve 21→the first heat exchanger 31 (fin heat exchanger)→on-off valve 50→the third electronic expansion valve 43→the third heat exchanger 33 (cold and warm sleeve)→the third three-way valve 23→the gas-liquid separator 70→the compressor 10.

[0105] Second heat exchanger 32 (hot water sleeve) to the second three-way valve 22 to the gas-liquid separator for low pressure side, so that the refrigerant from the second heat exchanger 32 (hot water sleeve) to the gas-liquid separator until the pressure balance, the system refrigerant participate in refrigeration and defrost cycle.

[0106] Please refer to Figure 5 , the controller in defrost mode, also can use hot water defrosting, enable the first heat exchanger 31 and the second heat exchanger 32, idle third heat exchanger 33, the specific control mode as follows:

[0107] SE1 control second three-way valve 22, the third three-way valve 23 power off, the first three-way valve 21 power on;

[0108] SE2 control third electronic expansion valve 43, the first flow control valve 61 closed; the second electronic expansion valve 42, on-off valve 50 open; make the first heat exchanger 31 as condenser, the second heat exchanger 32 as evaporator, the third heat exchanger 33 idle.

[0109] This mode, the refrigerant circulation loop is: compressor 10→the first three-way valve 21→the first heat exchanger 31 (fin heat exchanger)→on-off valve 50→the second electronic expansion valve 42→the second heat exchanger 32 (hot water sleeve)→the second three-way valve 22→the gas-liquid separator 70→the compressor 10.

[0110] Third heat exchanger 33 (cold and warm sleeve) connects the third three-way valve 23 to the gas-liquid separator for the low-pressure side, so that the refrigerant flows from the third heat exchanger 33 (cold and warm sleeve) to the gas-liquid separator until the pressure balance, the system refrigerant participates in the defrosting cycle.

[0111] Hot water defrosting mode and cold and warm sleeve defrosting mode are processed respectively, when the idle heat exchanger is cold and warm sleeve or hot water sleeve, that is, only a single load is connected (such as the water circuit of the unit only connects the hot water sleeve water circuit), the unit can also normally use all functions of a single load, improve the stability and variability of the system.

[0112] Based on the above settings, please refer to Figure 6 In the full heat recovery mode (heating water to produce cold air), the controller controls the system refrigerant to participate in the heating cycle by the following control:

[0113] SF1 controls the first three-way valve 21 and the third three-way valve 23 to be powered off, and the second three-way valve 22 to be powered on;

[0114] SF2 controls the third electronic expansion valve 43 and the on-off valve 50 to be closed; the second electronic expansion valve 42 and the first flow control valve 61 are opened; the second heat exchanger 32 is used as a condenser, the third heat exchanger 33 is used as an evaporator, and the first heat exchanger 31 is idle.

[0115] In this working mode, the circulation loop of the refrigerant is: compressor 10→second three-way valve 22→second heat exchanger 32 (hot water sleeve)→second electronic expansion valve 42→first flow control valve 61→third heat exchanger 33 (cold and warm sleeve)→third three-way valve 23→gas-liquid separator 70→compressor 10.

[0116] The first heat exchanger 31 (finned heat exchanger) connects the first three-way valve 21 to the gas-liquid separator for the low-pressure side, so that the refrigerant flows from the first heat exchanger 31 (finned heat exchanger) to the gas-liquid separator until the pressure balance, the system refrigerant participates in the full heat recovery cycle.

[0117] Embodiment 2

[0118] Please refer to Figure 7The present embodiment is a four-way heat pump system, i.e. N = 4, comprising: a compressor 10, four first, second, third and fourth three-way valves 21, 22, 23 and 24 arranged in parallel, and a first heat exchanger 31 connected with the first three-way valve 21, a second heat exchanger 32 connected with the second three-way valve 22, a third heat exchanger 33 connected with the third three-way valve 23, and a fourth heat exchanger 34 connected with the fourth three-way valve 24, and a second electronic expansion valve 42 connected with the second heat exchanger 32, a third electronic expansion valve 43 connected with the third heat exchanger 33, and a fourth electronic expansion valve 44 connected with the fourth heat exchanger 34, and a on-off valve 50 connected with the first heat exchanger 31, and a first flow control valve 61 and a second flow control valve 62 connected with the low-pressure side of the second electronic expansion valve 42 and the fourth electronic expansion valve 44 and the high-pressure side between the third electronic expansion valve 43, and a gas-liquid separator 70, and a controller.

[0119] The specific connection and arrangement of the four-way heat pump system are as follows.

[0120] The first three-way valve 21 has a gas inlet end C1 connected with the exhaust port A of the compressor 10; the second three-way valve 22 has a gas inlet end C2 connected with the exhaust port A; the third three-way valve 23 has a gas inlet end C3 connected with the exhaust port A; and the fourth three-way valve 24 has a gas inlet end C4 connected with the exhaust port A.

[0121] The first heat exchanger 31 has a first port F1 connected with the working end E1 of the first three-way valve 21; the second heat exchanger 32 has a first port F2 connected with the working end E2 of the second three-way valve 22; the third heat exchanger 33 has a first port F3 connected with the working end E3 of the third three-way valve 23; and the fourth heat exchanger 34 has a first port F4 connected with the working end E4 of the fourth three-way valve 24.

[0122] The second electronic expansion valve 42 has a high-pressure side H2 connected with the second port G2 of the second heat exchanger 32; the third electronic expansion valve 43 has a high-pressure side H3 connected with the second port G3 of the third heat exchanger 33; and the fourth electronic expansion valve 44 has a high-pressure side H4 connected with the second port G4 of the fourth heat exchanger 34.

[0123] The on-off valve 50 has one end connected with the second port G1 of the first heat exchanger 31, and the other end connected with the low-pressure side O2 of the second electronic expansion valve 42, the low-pressure side O3 of the third electronic expansion valve 43, and the low-pressure side O4 of the fourth electronic expansion valve 44, respectively.

[0124] The first flow control valve 61 is connected with the low pressure side 02 of the second electronic expansion valve 42 through the low pressure connection port P1, and is connected with the high pressure side H3 of the third electronic expansion valve 43 through the high pressure connection port Q1; the second flow control valve 62 is connected with the low pressure side 04 of the fourth electronic expansion valve 44 through the low pressure connection port P2, and is connected with the high pressure side H3 of the third electronic expansion valve 43 through the high pressure connection port Q2.

[0125] The gas-liquid separator 70 is connected with the exhaust end D1 of the first three-way valve 21, the exhaust end D2 of the second three-way valve 22, the exhaust end D3 of the third three-way valve 23, and the exhaust end D4 of the fourth three-way valve 24 through the gas inlets R respectively, and is connected with the back gas port B of the compressor 10 through the gas outlet S.

[0126] In the embodiment, the first heat exchanger 31 is a fin heat exchanger, the second heat exchanger 32 is a hot water jacket, the third heat exchanger 33 is a cooling and heating jacket, and the fourth heat exchanger 34 is a floor heating jacket. Due to the absence of the full heat recovery mode of heating-water production and floor heating-water production, the fourth flow control valve 64 and the fifth flow control valve 65 are idle, i.e., always in the closed state, and can be removed.

[0127] Based on the above settings, please refer to Figure 7 In the heating + heating working mode of the embodiment, the controller realizes the heating + heating mode by the following control, in which the refrigerant in the system participates in the heating cycle:

[0128] The SG1 controls the first three-way valve 21 and the second three-way valve 22 to be powered off, and controls the third three-way valve 23 and the fourth three-way valve 24 to be powered on.

[0129] The SG2 controls the second electronic expansion valve 42 and each flow control valve to be closed, controls the third electronic expansion valve 43 and the fourth electronic expansion valve 44 to be opened, and controls the on-off valve 50 to be opened, so that the third heat exchanger 33 and the fourth heat exchanger 34 act as condensers, the first heat exchanger 31 acts as an evaporator, and the second heat exchanger 32 is idle.

[0130] In the working mode, the circulation loop of the refrigerant is: the compressor 10→the third three-way valve 23 and the fourth three-way valve 24→the third heat exchanger 33 and the fourth heat exchanger 34→the third electronic expansion valve 43 and the fourth electronic expansion valve 44→the on-off valve 50→the first heat exchanger 31 (fin heat exchanger)→the first three-way valve 21→the gas-liquid separator 70→the compressor 10.

[0131] The second heat exchanger 32 (hot water jacket) is connected with the second three-way valve 22 to the low pressure side of the gas-liquid separator, so that the refrigerant flows from the second heat exchanger 32 (hot water jacket) to the gas-liquid separator until the pressure is balanced, and the refrigerant in the system participates in the heating cycle.

[0132] Based on the above settings, please refer to Figure 8In the heating water + heating mode of the embodiment, the controller realizes the heating water + heating mode by the following control, and the refrigerant in the system participates in the heating cycle:

[0133] The SH1 controls the first three-way valve 21 and the third three-way valve 23 to be powered off, and the second three-way valve 22 and the fourth three-way valve 24 to be powered on.

[0134] The SH2 controls the third electronic expansion valve 43 and each flow control valve to be closed, and the second electronic expansion valve 42, the fourth electronic expansion valve 44, and the on-off valve 50 to be opened, so that the second heat exchanger 32 and the fourth heat exchanger 34 serve as condensers, the first heat exchanger 31 serves as an evaporator, and the third heat exchanger 33 is idle.

[0135] In this working mode, the circulation loop of the refrigerant is: the compressor 10→the second three-way valve 22 and the fourth three-way valve 24→the second heat exchanger 32 and the fourth heat exchanger 34→the second electronic expansion valve 42 and the fourth electronic expansion valve 44→the on-off valve 50→the first heat exchanger 31 (the fin heat exchanger)→the first three-way valve 21→the gas-liquid separator 70→the compressor 10.

[0136] The third heat exchanger 33 (the cooling and heating coil) connects the third three-way valve 23 to the gas-liquid separator on the low-pressure side, so that the refrigerant flows from the third heat exchanger 33 (the cooling and heating coil) to the gas-liquid separator until the pressure is balanced, and the refrigerant in the system participates in the heating cycle.

[0137] Based on the above settings, please refer to Figure 9 In the heating water + heating mode of the embodiment, the controller realizes the heating water + heating mode by the following control, and the refrigerant in the system participates in the heating cycle:

[0138] The SK1 controls the first three-way valve 21 and the fourth three-way valve 24 to be powered off, and the second three-way valve 22 and the third three-way valve 23 to be powered on.

[0139] The SK2 controls the fourth electronic expansion valve 44 and each flow control valve to be closed, and the second electronic expansion valve 42, the third electronic expansion valve 43, and the on-off valve 50 to be opened, so that the second heat exchanger 32 and the third heat exchanger 33 serve as condensers, the first heat exchanger 31 serves as an evaporator, and the fourth heat exchanger 34 is idle.

[0140] In this working mode, the circulation loop of the refrigerant is: the compressor 10→the second three-way valve 22 and the third three-way valve 23→the second heat exchanger 32 and the third heat exchanger 33→the second electronic expansion valve 42 and the third electronic expansion valve 43→the on-off valve 50→the first heat exchanger 31 (the fin heat exchanger)→the first three-way valve 21→the gas-liquid separator 70→the compressor 10.

[0141] The fourth heat exchanger 34 (underfloor heating pipe) connects the third three-way valve 23 to the gas-liquid separator as a low-pressure side, so that the refrigerant flows from the fourth heat exchanger 34 (underfloor heating pipe) to the gas-liquid separator until pressure balance, and the refrigerant in the system participates in the heating cycle.

[0142] Based on the above settings, please refer to Figure 10 The embodiment is a full heat recovery mode of heating water + underfloor heating + refrigeration, and the control method of the controller is as follows:

[0143] The SL1 controls the first three-way valve 21, the third three-way valve 23 to be powered off, and the second three-way valve 22, the fourth three-way valve 24 to be powered on.

[0144] The SL2 controls the third electronic expansion valve 43, the on-off valve 50 to be closed; the second electronic expansion valve 42, the fourth electronic expansion valve 44, the first flow control valve 61, the second flow control valve 62 to be opened; so that the second heat exchanger 32, the fourth heat exchanger 34 act as condensers, the third heat exchanger 33 acts as an evaporator, and the first heat exchanger 31 is idle.

[0145] In this working mode, the circulation loop of the refrigerant is: the compressor 10→the second three-way valve 22, the fourth three-way valve 24→the second heat exchanger 32 (hot water pipe), the fourth heat exchanger (underfloor heating pipe)→the second electronic expansion valve 42, the fourth electronic expansion valve 44→the first flow control valve 61, the second flow control valve 62→the third heat exchanger 33 (cooling and heating pipe)→the third three-way valve 23→the gas-liquid separator 70→the compressor 10.

[0146] The first heat exchanger 31 (fin heat exchanger) connects the first three-way valve 21 to the gas-liquid separator as a low-pressure side, so that the refrigerant flows from the first heat exchanger 31 (fin heat exchanger) to the gas-liquid separator until pressure balance, and the refrigerant in the system participates in the full heat recovery cycle.

[0147] Based on the above settings, please refer to Figure 11 The embodiment is a full heat recovery mode of heating water + refrigeration, and the control method of the controller is as follows:

[0148] The SL1 controls the first three-way valve 21, the third three-way valve 23, the fourth three-way valve 24 to be powered off, and the second three-way valve 22 to be powered on.

[0149] The SL2 controls the third electronic expansion valve 43, the fourth electronic expansion valve 44, the on-off valve 50 to be closed; the second electronic expansion valve 42, the first flow control valve 61 to be opened; so that the second heat exchanger 32 acts as a condenser, the third heat exchanger 33 acts as an evaporator, and the first heat exchanger 31, the fourth heat exchanger 34 are idle.

[0150] In this working mode, the circulation loop of refrigerant is: compressor 10→ second three-way valve 22→ second heat exchanger 32 (hot water jacket)→ second electronic expansion valve 42→ first flow control valve 61→ third heat exchanger 33 (cooling and heating jacket)→ third three-way valve 23→ gas-liquid separator 70→ compressor 10.

[0151] The first heat exchanger 31 (fin heat exchanger) connects the first three-way valve 21 to the gas-liquid separator as the low-pressure side, so that the refrigerant flows from the first heat exchanger 31 (fin heat exchanger) to the gas-liquid separator until pressure balance, and the fourth heat exchanger 34 is the same, so that the refrigerant in the system participates in the total heat recovery cycle.

[0152] The multi-connected heat pump system has the following beneficial technical effects.

[0153] 1) The system sets N parallel three-way valves at the exhaust port of the compressor, the exhaust end of each three-way valve is connected to the gas return port of the compressor, the working end of each three-way valve is connected to a heat exchanger, the second heat exchanger to the Nth heat exchanger is connected to an electronic expansion valve, and then connected to the first heat exchanger, forming a structure of refrigerant circulation loop, and the controller controls the opening and closing of each three-way valve and each electronic expansion valve to control the flow direction of the system refrigerant, so that the system does not exist in series and shunt, and then realizes the control of multiple working modes; based on the same structure, when there is an idle heat exchanger, the controller controls the opening and closing of each electronic expansion valve, so that the idle heat exchanger is in a low-pressure state in the system, so that the refrigerant in the non-idle heat exchanger can be matched according to the single system charging amount, covering the working conditions, so that the refrigerant participates in the working cycle in each mode, improving the efficiency of the system; based on the same structure, when the first heat exchanger as an evaporator needs to be defrosted, the heat exchanger for heating can be selected to complete the refrigerant circulation loop, and the heat exchanger for heating water can also be selected to complete the refrigerant circulation loop, the system has fault tolerance, and the stability of the system defrosting is further improved.

[0154] 2) The system sets a flow control valve between the first heat exchanger as an evaporator and the connecting pipeline of each electronic expansion valve, and by closing the flow control valve, the system has a total heat recovery mode, and free cold can be provided to users with cold demand when running heating or hot water.

[0155] 3) The system sets a flow control valve at the low-pressure side of the electronic expansion valve connected to the second heat exchanger to the Nth heat exchanger, which is connected to the high-pressure side of the electronic expansion valve corresponding to the heat exchanger with cold release, so that the refrigerant flowing out of the heat exchanger only needs to pass through the throttling of an electronic expansion valve to flow into the heat exchanger as an evaporator, without passing through the low-pressure side of an electronic expansion valve, so that the system does not exist in transition throttling, solving the series of problems of reducing refrigeration / heating effect and reducing system efficiency caused by excessive throttling in the existing multi-connected system.

[0156] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Expressions such as "first", "second", "third", etc. are used herein to distinguish between similar elements and not to imply or create any specific order, sequence, or hierarchy between those elements. The above description is presented to enable any person skilled in the art to make and use the present embodiments. The above descriptions are provided as is and no admission is made that any particular embodiment is the best of all possible embodiments.

[0157] The embodiments described above are merely given as non-limiting examples, but the application is not restricted thereto. It will be understood by those of ordinary skill in the art that various modifications can be made to the embodiments described herein without departing from the spirit or scope of the application.

Claims

1. A multi-generation heat pump system, characterized in that, Comprise: A compressor, provided with an exhaust port A and a return gas port B; N three-way valves are arranged in parallel, the i-th three-way valve is provided with an air inlet end Ci, an air outlet end Di and a working end Ei, wherein, , ; the air inlet end of each three-way valve is connected with the air outlet A, and the air outlet end is connected with the air return port B; N heat exchangers, the i heat exchanger is provided with a first port Fi and a second port Gi; the first port of each heat exchanger is connected with the working end of each three-way valve one by one; N-1 electronic expansion valves, the jth electronic expansion valve is provided with a high-pressure side Hj and a low-pressure side Oj, wherein, ; the high-pressure side of each electronic expansion valve is respectively and individually connected with the second port of the second heat exchanger to the Nth heat exchanger; the low-pressure side of each electronic expansion valve is connected with the second port of the first heat exchanger; Further comprising a on-off valve, one end of the on-off valve is connected with the second port G1 of the first heat exchanger, and the other end is connected with the low pressure side of each electronic expansion valve; Further comprising a plurality of flow control valves, the flow control valves are set according to the total heat recovery mode of the multi-connected heat pump system, so that the multi-connected heat pump system is connected with the high pressure side of the electronic expansion valve connected with the heat exchanger as the evaporator and the low pressure side of the electronic expansion valve connected with the heat exchanger as the condenser one by one in the total heat recovery mode, A controller, electrically connected and / or communicated with each three-way valve, each electronic expansion valve, on-off valve, each flow control valve, and controls the opening and closing of each three-way valve, each electronic expansion valve, on-off valve, each flow control valve according to the working mode of the system; Further comprising a gas-liquid separator, the gas-liquid separator is provided with an air inlet R and an air outlet S; the air inlet R is connected with the exhaust end D of each three-way valve, and the air outlet S is connected with the return gas port B of the compressor.

2. The multi-circuit heat pump system according to claim 1, characterized in that, The N=3, that is, the multi-connected heat pump system is a three-connected heat pump system, the three-connected heat pump system comprises: A compressor; Three first three-way valves, second three-way valves and third three-way valves arranged in parallel; A first heat exchanger connected with the first three-way valve, a second heat exchanger connected with the second three-way valve and a third heat exchanger connected with the third three-way valve; A second electronic expansion valve connected with the second heat exchanger and a second electronic expansion valve connected with the third heat exchanger; A on-off valve, one end of which is connected with the first heat exchanger, and the other end of which is connected with the second electronic expansion valve and the third electronic expansion valve; A controller electrically connected and / or communicated with each valve.

3. The multi-circuit heat pump system according to claim 2, characterized in that, The first heat exchanger is a fin heat exchanger, the second heat exchanger is a hot water sleeve, the third heat exchanger is a cold and warm sleeve, the on-off valve is an electromagnetic two-way valve, and the controller realizes the total heat recovery mode by the following way: Control the first three-way valve and the third three-way valve to be powered off, and the second three-way valve to be powered on; Control the on-off valve to be closed, and the second electronic expansion valve and the third electronic expansion valve to be opened, so that the second heat exchanger works as a condenser, the third heat exchanger works as an evaporator, and the first heat exchanger is idle.

4. The multi-circuit heat pump system according to claim 3, characterized in that, Further comprising a flow control valve, one end of the flow control valve is connected with the low pressure side of the second electronic expansion valve, and the other end is connected with the high pressure side of the third electronic expansion valve, and the controller realizes the total heat recovery mode and avoids secondary throttling by the following way: Control the first three-way valve and the third three-way valve to be powered off, and the second three-way valve to be powered on; Control the third electronic expansion valve and the on-off valve to be closed, and the second electronic expansion valve and the flow control valve to be opened; so that the second heat exchanger works as a condenser, the third heat exchanger works as an evaporator, and the first heat exchanger is idle.

5. The multi-circuit heat pump system of claim 1, wherein, The N=4, that is, the multi-connected heat pump system is a four-connected heat pump system, the four-connected heat pump system comprises: A compressor; Four first three-way valves, second three-way valves, third three-way valves and fourth three-way valves arranged in parallel; a first heat exchanger connected with the first three-way valve, a second heat exchanger connected with the second three-way valve, and a third heat exchanger connected with the third three-way valve, and a fourth heat exchanger connected with the fourth three-way valve; a second electronic expansion valve connected with the second heat exchanger, a third electronic expansion valve connected with the third heat exchanger, and a fourth electronic expansion valve connected with the fourth heat exchanger; an on-off valve, one end of which is connected with the first heat exchanger, and the other end of which is connected with the second electronic expansion valve, the third electronic expansion valve, and the fourth electronic expansion valve; a controller electrically connected and / or communicatively connected with the above valves.

6. The multi-circuit heat pump system according to claim 5, characterized in that, The first heat exchanger is a fin heat exchanger, the second heat exchanger is a hot water jacket, the third heat exchanger is a cold and warm jacket, and the fourth heat exchanger is a floor heating jacket; the on-off valve is an electromagnetic two-way valve, and the controller realizes the full heat recovery mode of hot water production + refrigeration by the following way: controlling the first three-way valve, the third three-way valve, and the fourth three-way valve to be powered off, and the second three-way valve to be powered on; controlling the fourth electronic expansion valve and the on-off valve to be closed, and the second electronic expansion valve and the third electronic expansion valve to be opened, so that the second heat exchanger works as a condenser, the third heat exchanger works as an evaporator, and the first heat exchanger and the fourth heat exchanger are idle; The controller realizes the full heat recovery mode of heating + hot water production + refrigeration by the following way: controlling the first three-way valve and the third three-way valve to be powered off, and the second three-way valve and the fourth three-way valve to be powered on; controlling the on-off valve to be closed, and the second electronic expansion valve, the third electronic expansion valve, and the fourth electronic expansion valve to be opened, so that the second heat exchanger and the fourth heat exchanger work as condensers, the third heat exchanger works as an evaporator, and the first heat exchanger is idle.

7. The multi-circuit heat pump system according to claim 6, characterized in that, The first flow control valve has one end connected with the low-pressure side of the second electronic expansion valve and the other end connected with the high-pressure side of the third electronic expansion valve, and the second flow control valve has one end connected with the low-pressure side of the fourth electronic expansion valve and the other end connected with the high-pressure side of the third electronic expansion valve, and the controller realizes the full heat recovery mode of hot water production + refrigeration and avoids secondary throttling by the following way: controlling the first three-way valve, the third three-way valve, and the fourth three-way valve to be powered off, and the second three-way valve to be powered on; controlling the third electronic expansion valve, the fourth electronic expansion valve, and the on-off valve to be closed, and the second electronic expansion valve and the first flow control valve to be opened, so that the second heat exchanger works as a condenser, the third heat exchanger works as an evaporator, and the first heat exchanger and the fourth heat exchanger are idle; The controller realizes the full heat recovery mode of heating + hot water production + refrigeration and avoids secondary throttling by the following way: controlling the first three-way valve and the third three-way valve to be powered off, and the second three-way valve and the fourth three-way valve to be powered on; controlling the third electronic expansion valve and the on-off valve to be closed, and the second electronic expansion valve, the fourth electronic expansion valve, the first flow control valve, and the second flow valve to be opened, so that the second heat exchanger and the fourth heat exchanger work as condensers, the third heat exchanger works as an evaporator, and the first heat exchanger is idle.

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