Vapor injection heat pump system and operation method thereof

Abstract

A vapor injection heat pump system and an operation method is disclosed. The operation method includes a compressor, an indoor heat exchanger, a vapor injection module, an outdoor heat exchanger, and an evaporator includes an operation of performing control in one of a first heating mode which is a non-vapor injection heating mode in which a refrigerant introduced into the module is introduced into the outdoor heat exchanger and a second heating mode which is a vapor injection heating mode in which some of the refrigerant introduced into the vapor module is introduced into the compressor and the remaining refrigerant is introduced into the outdoor exchanger, wherein, in the operation of performing control, a flow of the refrigerant is maintained in the vapor injection module when the first heating mode is switched to the second heating mode or the second heating mode is switched to the first heating mode.

1 . An operation method of a vapor injection heat pump system which includes a compressor, an indoor heat exchanger, a vapor injection module, an outdoor heat exchanger, and an evaporator, the operation method comprising an operation of performing control in one of:
 a first heating mode which is a non-vapor injection heating mode in which a refrigerant introduced into the vapor injection module is introduced into the outdoor heat exchanger; and   a second heating mode which is a vapor injection heating mode in which some of the refrigerant introduced into the vapor module is introduced into the compressor and the remaining refrigerant is introduced into the outdoor exchanger,   wherein, in the operation of performing control, a flow of the refrigerant is maintained in the vapor injection module when the first heating mode is switched to the second heating mode or the second heating mode is switched to the first heating mode.   
     
     
         2 . The operation method of  claim 1 , wherein, in the operation of performing control, a start time of the second heating mode is set to not be earlier than an end time of the first heating mode. 
     
     
         3 . The operation method of  claim 1 , wherein, in the operation of performing control:
 an end time of the first heating mode and a start time of the second heating mode are set to be the same; or   the end time of the first heating mode is set to be later than the start time of the second heating mode.   
     
     
         4 . The operation method of  claim 1 , wherein, in the operation of performing control, when the control is performed in the second heating mode:
 the second heating mode is performed for a predetermined time and then switched to the first heating mode; and   a start time of the first heating mode is set to not be earlier than an end time of the second heating mode.   
     
     
         5 . The operation method of  claim 1 , wherein, in the operation of performing control:
 the end time of the first heating mode and the start time of the second heating mode are set to be the same; or   the end time of the second heating mode is set to be later than the start time of the first heating mode.   
     
     
         6 . The operation method of  claim 1 , wherein the operation of performing control performs control in the first heating mode for a predetermined time and then control in the second heating mode or perform direct control in the second heating mode according to a pressure difference between an inlet side pressure and an outlet side pressure of the compressor. 
     
     
         7 . The operation method of  claim 6 , wherein the operation of performing control performs:
 control in the second heating mode when the pressure difference between the inlet side pressure and the outlet side pressure of the compressor is greater than a predetermined reference pressure; and   control in the first heating mode when the pressure difference is smaller than or equal to the predetermined reference pressure.   
     
     
         8 . A vapor injection heat pump system comprising:
 a compressor;   an indoor heat exchanger;   a vapor injection module;   an outdoor heat exchanger;   an evaporator; and   a controller,   wherein the vapor injection module includes:   a first expansion unit which blocks a flow of a condensed refrigerant or expands and transfers the condensed refrigerant according to a first heating mode which is a non-vapor injection heating mode in which the refrigerant introduced into the vapor injection module is introduced into the outdoor heat exchanger or a second heating mode which is a vapor injection heating mode in which some of the refrigerant introduced into the vapor module is introduced into the compressor and the remaining refrigerant is introduced into the outdoor exchanger;   a gas-liquid separator which separates the refrigerant received from the first expansion unit into a gas phase refrigerant and a liquid phase refrigerant; and   a second expansion unit which allows the condensed refrigerant to pass therethrough or expand or allows the liquid phase refrigerant separated in the gas-liquid separator to expand according to the first heating mode or the second heating mode, and   the controller controls the first expansion unit and the second expansion unit according to the first heating mode or the second heating mode and controls the flow of the refrigerant to be maintained in the vapor injection module when the first heating mode is switched to the second heating mode or the second heating mode is switched to the first heating mode.   
     
     
         9 . The vapor injection heat pump system of  claim 8 , wherein the controller sets a control time for the first expansion unit and a control time for the second expansion unit to be the same or sets the control time for the first expansion unit to be later than the control time for the second expansion unit when the first heating mode is performed for a predetermined time and then switched to the second heating mode. 
     
     
         10 . The vapor injection heat pump system of  claim 8 , wherein the controller sets a control time for the first expansion unit and a control time for the second expansion unit to be the same or sets the control time for the second expansion unit to be later than the control time for the first expansion unit when the second heating mode is performed for a predetermined time and then switched to the first heating mode. 
     
     
         11 . The vapor injection heat pump system of  claim 8 , wherein the controller performs control in the first heating mode for a predetermined time or perform direct control in the second heating mode according to a pressure difference between an inlet side pressure and an outlet side pressure of the compressor. 
     
     
         12 . The vapor injection heat pump system of  claim 8 , wherein the controller performs:
 control in the second heating mode when the pressure difference between the inlet side pressure and the outlet side pressure of the compressor is greater than a predetermined reference pressure; and   control in the first heating mode when the pressure difference is smaller than or equal to the predetermined reference pressure.   
     
     
         13 . The vapor injection heat pump system of  claim 8 , wherein in the first heating mode, the first expansion unit blocks the refrigerant, the second expansion unit expands the refrigerant. 
     
     
         14 . The vapor injection heat pump system of  claim 8 , wherein in the second heating mode, the first expansion unit expands the refrigerant, the second expansion unit expands the refrigerant. 
     
     
         15 . The vapor injection heat pump system of  claim 8 , wherein in the second heating mode, the first expansion unit expands the condensed refrigerant as a middle-pressure refrigerant, the second expansion unit expands the condensed refrigerant as a low-pressure refrigerant.