Vapor injection heat pump system and method for operating same

Abstract

A vapor injection heat pump system and a method of operating the same are disclosed. The system includes a compressor, an indoor heat exchanger, a vapor injection module, an outdoor heat exchanger, and an evaporator and in which the module includes a first expansion unit, a gas-liquid separator, and a second expansion unit. The method includes performing control in a first heating mode which is a non-vapor injection heating mode or a second heating mode which is a vapor injection heating mode, wherein, in the operation of performing control, a refrigerant introduced into the module is controlled to expand in the first expansion unit, not expand after passing through the gas-liquid separator, and pass through the second expansion unit in the first heating mode, and the refrigerant introduced into the module is controlled to expand primarily in the first expansion unit.

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 and in which the vapor injection module includes a first expansion unit, a gas-liquid separator, and a second expansion unit, the operation method comprising an operation of performing control:
 in a first heating mode which is a non-vapor injection heating mode; or   a second heating mode which is a vapor injection heating mode,   wherein, in the operation of performing control, a refrigerant introduced into the vapor injection module is controlled to expand in the first expansion unit, not expand after passing through the gas-liquid separator, and pass through the second expansion unit in the first heating mode, and   the refrigerant introduced into the vapor injection module is controlled to expand primarily in the first expansion unit, pass through the gas-liquid separator, and then expand secondarily in the second expansion unit in the second heating mode.   
     
     
         2 . The operation method of  claim 1 , wherein, in the operation of performing control, when the first heating mode is performed for a predetermined time and then switched to the second heating mode:
 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.   
     
     
         3 . The operation method of  claim 1 , wherein, in the operation of performing control:
 the second heating mode is performed for a predetermined time and then switched to the first heating mode; and   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 second heating mode is set to be later than the start time of the first heating mode.   
     
     
         4 . 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. 
     
     
         5 . The operation method of  claim 4 , wherein the operation of performing control performs:
 control in the second heating mode when a 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.   
     
     
         6 . 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 or a second heating mode which is a vapor injection heating mode;   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 refrigerant introduced into the vapor injection module to expand in the first expansion units, not expand after passing through the gas-liquid separator, and pass through the second expansion unit in the first heating mode and controls the refrigerant introduced into the vapor injection module to expand primarily in the first expansion unit and expand secondarily in the second expansion unit after passing through the gas-liquid separator in the second heating mode.   
     
     
         7 . The vapor injection heat pump system of  claim 6 , 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. 
     
     
         8 . The vapor injection heat pump system of  claim 6 , 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. 
     
     
         9 . The vapor injection heat pump system of  claim 6 , 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. 
     
     
         10 . The vapor injection heat pump system of  claim 9 , wherein the controller performs:
 control in the second heating mode when a 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.   
     
     
         11 . The operation method of  claim 1 , wherein in the first heating mode, the first expansion unit expands the refrigerant by adjusting an opening extent to meet the target control value, and the second expansion unit allows the refrigerant to pass by fully opening. 
     
     
         12 . The operation method of  claim 1 , wherein in the second heating mode, the first expansion unit expands the refrigerant by adjusting an opening extent to meet the target control value, and the second expansion unit by reducing the opening extent to meet the target control value. 
     
     
         13 . The operation method of  claim 1 , wherein in the second heating mode, the first expansion unit expands the refrigerant as a middle-pressure refrigerant, the second expansion unit expands the refrigerant as a low-pressure refrigerant. 
     
     
         14 . The operation method of  claim 9 , wherein in the first heating mode, the first expansion unit expands the refrigerant by adjusting an opening extent to meet the target control value, and the second expansion unit allows the refrigerant to pass by fully opening. 
     
     
         15 . The operation method of  claim 9 , wherein in the second heating mode, the first expansion unit expands the refrigerant by adjusting an opening extent to meet the target control value, and the second expansion unit by reducing the opening extent to meet the target control value. 
     
     
         16 . The operation method of  claim 9 , wherein in the second heating mode, the first expansion unit expands the refrigerant as a middle-pressure refrigerant, the second expansion unit expands the refrigerant as a low-pressure refrigerant.