Heat pump system and control method thereof

Abstract

The present disclosure provides a heat pump system and a control method. The heat pump system includes a compressor, a first flow path, a second flow path and a third flow path. The second end of the first flow path, the second end of the second flow path and the second end of the third flow path are connected. Two of the first end of the first flow path, the first end of the second flow path and the first end of the third flow path are connected to the inlet and outlet of the compressor in specific modes through a switching assembly so that the heat pump system can operate in one or more of a cooling mode, a heating mode, a hot water preparing mode and a cooling heat recovery mode.

What is claimed is: 
     
         1 . A heat pump system, comprising:
 a compressor;   a first flow path, which comprises a first end of the first flow path, a first heat exchanger, a first throttling device, and a second end of the first flow path in sequence;   a second flow path, which comprises a first end of a second flow path, a second heat exchanger, a second throttling device, and a second end of the second flow path in sequence;   a third flow path, which comprises a first end of the third flow path, a third heat exchanger, a first check valve, and a second end of the third flow path in sequence, wherein the first check valve on the third flow path only allows a fluid flowing in a direction toward the second end of the third flow path to pass through;   wherein the second end of the first flow path, the second end of the second flow path and the second end of the third flow path are connected;   a switching assembly, which can be switched between any two, three or four of the following connection modes:   a first connection mode, in which the first end of the first flow path is connected to an outlet of the compressor, and the first end of the second flow path is connected to an inlet of the compressor;   a second connection mode, in which the first end of the second flow path is connected to the outlet of the compressor, and the first end of the first flow path is connected to the inlet of the compressor;   a third connection mode, in which the first end of the third flow path is connected to the outlet of the compressor, and the first end of the first flow path is connected to the inlet of the compressor; and   a fourth connection mode, in which the first end of the third flow path is connected to the outlet of the compressor, and the first end of the second flow path is connected to the inlet of the compressor; and   a control system, which enables the heat pump system to operate in any two, three, or four of a cooling mode, a heating mode, a hot water preparing mode, and a cooling heat recovery mode;   in the cooling mode, the switching assembly is switched to the first connection mode, the first throttling device plays a throttling function, and the second throttling device is fully opened or bypassed;   in the heating mode, the switching assembly is switched to the second connection mode, the first throttling device plays a throttling function, and the second throttling device is bypassed;   in the hot water preparing mode, the switching assembly is switched to the third connection mode, the first throttling device plays a throttling function, and the second throttling device is in a closed state; and   in the cooling heat recovery mode, the switching assembly is switched to the fourth connection mode, the second throttling device plays a throttling function, and the first throttling device is in a closed state.   
     
     
         2 . The heat pump system according to  claim 1 , wherein the second flow path comprises a second check valve connected in parallel with the second throttling device, and the second check valve only allows a fluid flowing in a direction toward the second end of the second flow path to pass through. 
     
     
         3 . The heat pump system according to  claim 1 , wherein the second flow path comprises a solenoid valve connected in parallel with the second throttling device, and in the cooling mode, in the heat pump system, the solenoid valve is opened and the second throttling device is closed to bypass the second throttling device. 
     
     
         4 . The heat pump system according to  claim 1 , wherein the heat pump system further comprises a receiver, and the receiver comprises a single pipeline and is connected to or near a position where the second end of the first flow path, the second end of the second flow path and the second end of the third flow path are connected. 
     
     
         5 . The heat pump system according to  claim 1 , wherein the heat pump system further comprises a receiver which comprises a first pipeline and a second pipeline, the second end of the first flow path and the second end of the second flow path are connected to the first pipeline of the receiver, and the second end of the third flow path is connected to the second pipeline of the receiver. 
     
     
         6 . The heat pump system according to  claim 5 , wherein the heat pump system further comprises a solenoid valve, which is connected between the second pipeline of the receiver and a position on the second flow path between the second heat exchanger and the second throttling device. 
     
     
         7 . The heat pump system according to  claim 5 , wherein the heat pump system further comprises a second check valve, which is connected between the second pipeline of the receiver and a position on the second flow path between the second heat exchanger and the second throttling device, and which only allows a fluid flowing in a direction toward a second end of the second pipeline to pass through. 
     
     
         8 . The heat pump system according to  claim 1 , wherein the heat pump system comprises a cooling working condition, and under the cooling working condition, the heat pump system is switched among the cooling mode, the hot water preparing mode, and the cooling heat recovery mode; and/or
 the heat pump system comprises a heating working condition, and under the heating working condition, the heat pump system is switched between the heating mode and the hot water preparing mode, wherein the heat pump system performs defrosting by being switched to the first connection mode and fully opening the first throttling device.   
     
     
         9 . The heat pump system according to  claim 1 , wherein the compressor is an enhanced vapor injection compressor, the heat pump system further comprises an economizer, and the first flow path comprises a branch point and passes through a first pipeline of the economizer, and wherein in the heating mode and the hot water preparing mode, a refrigerant flowing from the second end of the first flow path toward the first end of the first flow path passes through the first pipeline of the economizer before passing through the first throttling device, and is divided at the branch point into a first part leading to the first throttling device and a second part leading to a branch; the second part of the refrigerant passes through a branch throttling device on the branch and a second pipeline of the economizer to exchange heat with the refrigerant in the first pipeline of the economizer, and the refrigerant passing through the second pipeline of the economizer is supplied to an enhanced vapor injection port of the compressor. 
     
     
         10 . The heat pump system according to  claim 1 , wherein the third flow path does not have a throttling device. 
     
     
         11 . The heat pump system according to  claim 1 , wherein the switching assembly comprises two four-way valves. 
     
     
         12 . A control method of a heat pump system, the heat pump system comprising:
 a compressor;   a first flow path, which comprises a first end of the first flow path, a first heat exchanger, a first throttling device, and a second end of the first flow path in sequence;   a second flow path, which comprises a first end of a second flow path, a second heat exchanger, a second throttling device, and a second end of the second flow path in sequence;   a third flow path, which comprises a first end of the third flow path, a third heat exchanger, a first check valve, and a second end of the third flow path in sequence, wherein the first check valve on the third flow path only allows a fluid flowing in a direction toward the second end of the third flow path to pass through;   wherein the second end of the first flow path, the second end of the second flow path and the second end of the third flow path are connected;   wherein the method comprising: operating the heat pump system in any two, three, or four of a cooling mode, a heating mode, a hot water preparing mode, and a cooling heat recovery mode; wherein:   in the cooling mode, the first end of the first flow path is connected to the outlet of the compressor, the first end of the second flow path is connected to the inlet of the compressor, the first throttling device plays a throttling function, and the second throttling device is fully opened or bypassed;   in the heating mode, the first end of the second flow path is connected to the outlet of the compressor, the first end of the first flow path is connected to the inlet of the compressor, the first throttling device plays a throttling function, and the second throttling device is bypassed;   in the hot water preparing mode, the first end of the third flow path is connected to the outlet of the compressor, the first end of the first flow path is connected to the inlet of the compressor, the first throttling device plays a throttling function, and the second throttling device is closed; and   in the cooling heat recovery mode, the first end of the third flow path is connected to the outlet of the compressor, the first end of the first flow path is connected to the inlet of the compressor, the second throttling device plays a throttling function, and the first throttling device is closed.   
     
     
         13 . The method according to  claim 12 , wherein the method comprises:
 operating the heat pump system under a cooling working condition, wherein the heat pump system is switched among the cooling mode, the hot water preparing mode, and the cooling heat recovery mode; and/or   operating the heat pump system under a heating working condition, wherein the heat pump system is switched between the heating mode and the hot water preparing mode;   the method further comprises: under the heating working condition, connecting the first end of the first flow path to the outlet of the compressor, connecting the first end of the second flow path to the inlet of the compressor, and fully opening the first throttling device to perform defrost.