Cold Climate Heat Pump with Vapor Injection System

Abstract

Heat pump systems that include vapor injection feature are disclosed. Embodiments may include a heat pump system that has two tandem scroll compressors. Each compressor is paired with a control valve that regulates the flow of vapor to the respective compressor. Both the control valves are in fluid communication with a single or common source for vapor injection and to the controller. During operation, the controller dynamically determines how much vapor injection is needed for each of the compressors based on the operational data of the compressors and, optionally, ambient environment data. The controller then operates the two valves to ensure that the right amount of vapor is injected into each compressor.

That which is claimed is: 
     
         1 . A heat pump system comprising:
 a vapor injection source coupled to a first control valve and a second control valve;   a first vapor injection port of a first compressor coupled to the first control valve;   a second vapor injection port of a second compressor coupled to the second control valve; and   a controller coupled to the first and the second control valves and the first and second compressors,   wherein the controller is operable to:
 determine first operational data of the first compressor; 
 determine second operational data of the second compressor; 
 operate, using the controller and based on the first operational data, the first control valve to deliver a first amount of vapor to the first compressor; and 
 operate, using the controller and based on the second operational data, the second control valve to deliver a second amount of vapor to the first compressor. 
   
     
     
         2 . The heat pump system of  claim 1  wherein the first amount of vapor is substantially the same as the second amount of vapor. 
     
     
         3 . The heat pump system of  claim 1 , wherein the controller is further operable to:
 determine, at a first time, that first operational data indicates that the first compressor is ON and the second operational data indicates that the second compressor is OFF;   open, at least partially, the first control valve to allow the vapor from the vapor injection source to flow to the first compressor; and   close the second control valve.   
     
     
         4 . The heat pump system of  claim 1 , wherein the first compressor has a first capacity and the second compressor has a second capacity and the first capacity is substantially same as the second capacity and wherein the controller is further operable to:
 determine, based on the first operational data, that the first compressor is ON;   determine, based on the second operational data, that the second compressor is ON;   open, at least partially, the first control valve;   open, at least partially, the second control valve; and   cause the vapor from the vapor injection source to flow to the first compressor and the second compressor, wherein the first amount of vapor and the second amount of vapor is substantially the same.   
     
     
         5 . The heat pump system of  claim 4 , wherein the controller is further operable to:
 determine, based on the first operational data, that the first compressor is operating at a first speed; and   determine, based on the second operational data, that the second compressor is operating at a second speed, wherein the first speed is about equal to the second speed.   
     
     
         6 . The heat pump system of  claim 1 , wherein the controller is further operable to:
 determine, based on the first operational data, that the first compressor is operating at a first speed; and   determine, based on the second operational data, that the second compressor is operating at a second speed, wherein the first speed is greater the second speed, wherein the first amount of vapor is greater than the second amount of vapor.   
     
     
         7 . The heat pump system of  claim 6 , wherein the first compressor has a first capacity and the second compressor has a second capacity and the first capacity is substantially equal to the second capacity. 
     
     
         8 . The heat pump system of  claim 1 , wherein the first compressor has a first capacity and the second compressor has a second capacity and the first capacity is greater than the second capacity and wherein the controller is further operable to:
 determine, based on the first operational data that the first compressor is ON;   determine, based on the second operational data, that the second compressor is ON;   open, at least partially, the first control valve;   open, at least partially, the second control valve; and   cause the vapor from the vapor injection source to flow to the first compressor and the second compressor, wherein the first amount of vapor is greater than the second amount of vapor is substantially the same.   
     
     
         9 . The heat pump system of  claim 7 , wherein the first compressor is operating at a first speed and the second compressor is operating at a second speed and wherein the first speed is equal to the second speed. 
     
     
         10 . The heat pump system of  claim 7 , wherein the first compressor has a first capacity and the second compressor has a second capacity and the first capacity is different than the second capacity, and wherein the controller is further operable to:
 determine, based on the first operation data, that the first compressor is operating at a first speed;   determine, based on the second operational data, that the second compressor is operating a second speed, wherein the first speed is different than the second speed;   operate the first control valve based on the first capacity and the first speed; and   operate the second control valve based on the second capacity and the second speed.   
     
     
         11 . A method of operating a heat pump system, the method comprising:
 determining first operational data of a first compressor;   determining second operational data of a second compressor;   operating, using a controller and based on the first operational data, a first control valve to deliver a first amount of vapor to the first compressor; and   operating, using the controller and based on the second operational data, a second control valve to deliver a second amount of vapor to the first compressor, wherein the controller is coupled to the first compressor, the second compressor, the first control valve, and the second control valve.   
     
     
         12 . The method of  claim 11 , further comprising:
 determining that the first compressor is ON;   determining that the second compressor is OFF;   opening, at least partially, the first control valve;   closing the second control valve; and   causing the first amount of vapor to travel to the first compressor; and   wherein the second amount of vapor is zero.   
     
     
         13 . The method  claim 11 , further comprising:
 determining that the first compressor is ON;   determining that the second compressor is ON;   opening, at least partially, the first control valve; and   opening, at least partially, the second control valve; and   wherein the first amount of vapor and the second amount of vapor are substantially the same.   
     
     
         14 . The method of  claim 13 , further comprising:
 determining that the first compressor is operating at a first speed; and   determining that the second compressor is operating at a second speed, wherein the first speed is substantially equal to the second speed.   
     
     
         15 . The method of  claim 13 , further comprising:
 determining that the first compressor has a first capacity; and   determining that the second compressor has a second capacity, wherein the first capacity is equal to the second capacity.   
     
     
         16 . The method of  claim 11 , further comprising:
 determining that the first compressor has a first capacity;   determining that the second compressor has a second capacity, wherein the first capacity is different than the second capacity;   determining that the first compressor is operating at a first speed;   determining that the second compressor is operating a second speed, wherein the first speed is different than the second speed;   operating the first control valve based on the first capacity and the first speed; and   operating the second control valve based on the second capacity and the second speed.   
     
     
         17 . The method of  claim 11 , further comprising:
 determining that first compressor has a first capacity;   determining that and the second compressor has a second capacity, wherein the first capacity is substantially same as the second capacity;   determining that the first compressor is ON;   determining that the second compressor is ON;   opening, at least partially, the first control valve; and   opening, at least partially, the second control valve; and   wherein the first amount of vapor and the second amount of vapor is substantially the same.   
     
     
         18 . The method of  claim 11 , further comprising:
 determining that the first compressor is operating at a first speed;   determining that the second compressor is operating at a second speed that is lower than the first speed;   determining that the first compressor is ON;   determining that the second compressor is ON;   opening, at least partially, the first control valve; and   opening, at least partially, the second control valve,   wherein the first amount of vapor is greater than the second amount of vapor.   
     
     
         19 . The method of  claim 18 , further comprising:
 determining that the first compressor has a first capacity; and   determining that the second compressor has a second capacity that is substantially equal to the first capacity.   
     
     
         20 . The method of  claim 11 , wherein the first amount of vapor and the second amount of vapor is substantially the same.