Heat pump system and the control method thereof

Abstract

A heat pump system and a control method thereof. The heat pump system includes a compressor; a reversing valve configured to selectively connect the compressor inlet and the compressor outlet to a first flow path and a second flow path; a heat source-side heat exchanger on the first flow path; a user-side heat exchanger on the second flow path; a first branch and a second branch between the first flow path and the second flow path, the first branch is provided with a first valve and a second valve, and the second branch is provided with a first throttling device and a second throttling device; and an economizer connected between a first position between the first valve and the second valve on the first branch and a second position between the first throttling device and the second throttling device on the second branch.

What is claimed is: 
     
         1 . A heat pump system, comprising:
 a compressor having a compressor inlet and a compressor outlet;   a reversing valve configured to selectively connect the compressor inlet and the compressor outlet to a first flow path and a second flow path;   a heat source-side heat exchanger on the first flow path;   a user-side heat exchanger on the second flow path;   a first branch and a second branch between the first flow path and the second flow path, wherein the first branch is provided with a first valve and a second valve, and the second branch is provided with a first throttling device and a second throttling device; and   an economizer connected between a first position between the first valve and the second valve on the first branch and a second position between the first throttling device and the second throttling device on the second branch.   
     
     
         2 . The heat pump system according to  claim 1 , wherein the compressor is an Enhanced Vapor Injection compressor, where the Enhanced Vapor Injection compressor further comprises an air supplement port, and the economizer comprises a port connected with the air supplement port. 
     
     
         3 . The heat pump system according to  claim 2 , wherein the economizer is a flash tank, an inlet of the flash tank being connected to the first position, a gas-phase outlet of the flash tank being connected to the air supplement port, and a liquid-phase outlet of the flash tank being connected to the second position. 
     
     
         4 . The heat pump system according to  claim 2 , wherein the economizer is a heat exchanger comprising a first pipeline and a second pipeline, where the first pipeline is connected between the first position and the second position, and a branch path is branched out at a third position between the first position or the second position and the economizer, wherein the branch path is provided with an additional throttling device, and is connected to the air supplement port of the compressor through the second pipeline of the economizer. 
     
     
         5 . The heat pump system according to  claim 1 , wherein the first valve is a check valve that only allows refrigerant fluid to flow from the first flow path to the first position, and the second valve is a check valve that only allows refrigerant fluid to flow from the second flow path to the first position. 
     
     
         6 . The heat pump system according to  claim 1 , wherein the first throttling device and the second throttling device are expansion valves. 
     
     
         7 . The heat pump system according to  claim 6 , wherein the heat pump system further comprises a controller that controls the first throttling device and the second throttling device, where the controller is configured to turn off the first throttling device and allow the second throttling device to play a throttling role in a cooling mode, and to turn off the second throttling device and allow the first throttling device to play a throttling role in a heating mode. 
     
     
         8 . The heat pump system according to  claim 7 , wherein the first valve and the second valve are cut-off valves, and the controller is configured to control the first valve and the second valve, so that the first valve is turned on and the second valve is turned off in the cooling mode, and the second valve is turned on and the first valve is turned off in the heating mode. 
     
     
         9 . A control method of a heat pump system for use in the heat pump system according to  claim 1 , the method comprising:
 turning off the first throttling device and allowing the second throttling device to play a throttling role in the cooling mode, so that refrigerant passes through the first valve, the economizer and the second throttling device in turn; and   turning off the second throttling device and allowing the first throttling device to play a throttling role in the heating mode, so that refrigerant passes through the second valve, the economizer and the first throttling device in turn.   
     
     
         10 . The method according to  claim 9 , further comprising:
 using a flash tank as an economizer, so that after refrigerant enters the flash tank, gas-phase refrigerant is delivered to the air supplement port of the compressor, and liquid-phase refrigerant is delivered to the first throttling device or the second throttling device; or   using a heat exchanger comprising a first pipeline and a second pipeline as the economizer, and dividing the refrigerant into a first part and a second part before it enters the first pipeline or after it leaves the first pipeline, wherein the first part of the refrigerant is delivered to the first throttling device or the second throttling device, and the second part of the refrigerant is delivered to the air supplement port of the compressor after passing through an additional throttling device and then through the second pipeline of the economizer.