Solar augmented refrigeration cycle

Abstract

A method of controlling a refrigeration cycle device that includes refrigerant, a variable speed compressor, a condenser, a solar heater, a sensor, an expansion valve, an evaporator and a controller, the method including compressing the refrigerant using the compressor, in the condenser, cooling the refrigerant and condensing the refrigerant into a liquid state, in the solar heater, heating the refrigerant using solar energy, using the sensor, determining a pressure or a temperature of the refrigerant after it has been heated in the solar heater, and controlling the speed of the variable speed compressor using a closed-loop control scheme based at least in part on the determined pressure or temperature of the refrigerant.

1 . A method of controlling a refrigeration cycle device that includes refrigerant, a compressor, a condenser, a solar heater, a sensor, an expansion valve, an evaporator and a controller, wherein the compressor is operated by a variable speed motor which is operated by a variable speed drive, the method comprising:
 compressing the refrigerant using the compressor, wherein the refrigerant exits the compressor as a vapor;   in the condenser, cooling the refrigerant and condensing the refrigerant into a liquid state;   in the solar heater, heating the refrigerant using solar energy;   using the sensor, determining a pressure or a temperature of the refrigerant directly after it has been heated in the solar heater; and   in the variable speed drive, using a closed-loop control scheme, controlling the speed of the variable speed motor based at least in part on the determined pressure or temperature of the refrigerant directly after it has been heated in the solar heater.   
     
     
         2 . The method of  claim 1 , wherein the solar heater is plumbed between the condenser and the expansion valve. 
     
     
         3 . The method of  claim 1 , wherein the solar heater is plumbed between the compressor and the condenser. 
     
     
         4 . The method of  claim 1 , wherein the solar heater is plumbed between the compressor and a reversing valve in a heat pump. 
     
     
         5 . The method of  claim 1 , further comprising:
 determining the pressure of the refrigerant after the evaporator and before the compressor;   in the controller, controlling the speed of the variable speed motor based on the pressure of the refrigerant after the evaporator and before the compressor.   
     
     
         6 . The method of  claim 1 , further comprising:
 determining the pressure of the refrigerant after the evaporator and before the compressor;   in the controller, controlling the speed of the variable speed motor based on both the pressure of the refrigerant after the evaporator and before the compressor and the pressure or temperature of the refrigerant directly after it has been heated in the solar heater.   
     
     
         7 . The method of  claim 1 , further comprising:
 determining the pressure of the refrigerant after the compressor;   determining the pressure of the refrigerant after the solar panel; and   in the controller, controlling the speed of the variable speed motor based on both the pressure of the refrigerant after the compressor and after the solar panel.   
     
     
         8 . The method of  claim 1 , further comprising:
 determining the pressure of the refrigerant after the solar panel;   determining the pressure of the refrigerant after the condenser but prior to the expansion valve; and   in the controller, controlling the speed of the variable speed motor based on both the pressure of the refrigerant after the condenser and after the solar panel.   
     
     
         9 . The method of  claim 1 , further comprising:
 comparing a measured temperature in a conditioned space to a setpoint temperature and determining a difference;   in the controller, controlling the speed of the variable speed motor based on both the difference between the measured temperature in the conditioned space and the setpoint and the pressure or temperature of the refrigerant directly after it has been heated in the solar heater and after the condenser.   
     
     
         10 . The method of  claim 1 , further comprising:
 comparing a measured temperature in a conditioned space to a setpoint temperature and determining a difference;   in the controller, controlling the speed of the variable speed motor based on both the difference between the measured temperature in the conditioned space and the setpoint and both the pressure or temperature of the refrigerant directly after the compressor and the pressure or temperature of the refrigerant after the solar panel prior to the expansion valve.   
     
     
         11 . A method of retrofitting a refrigeration cycle device with a solar heater, wherein the refrigeration cycle device includes a refrigerant, a compressor, a condenser, and OEM condenser motor, an OEM sensor, an expansion valve, an evaporator and a controller, the method comprising:
 plumping a solar heater either between the condenser and the expansion valve or between the compressor and the condenser or between the compressor and a reversing valve in a heat pump;   adding a variable speed motor to the compressor;   installing a supplemental variable speed drive that controls the variable speed motor;   installing a replacement sensor directly after the solar heater;   coupling the replacement sensor to the controller;   installing a controller to control the variable speed drive based, in part, on temperature or pressure data determined by the replacement sensor using a closed-loop control scheme.   
     
     
         12 . The method of  claim 11 , wherein the solar heater is plumbed between the condenser and the expansion valve. 
     
     
         13 . The method of  claim 11 , wherein the solar heater is plumbed between the compressor and the condenser. 
     
     
         14 . The method of  claim 11 , wherein the solar heater is plumbed between the compressor and a reversing valve in a heat pump. 
     
     
         15 . A method of retrofitting a refrigeration cycle device with a solar heater, wherein the refrigeration cycle device includes a refrigerant, an OEM compressor with variable speed drive, a condenser, OEM sensor, an expansion valve, an evaporator and a controller, the method comprising:
 plumbing a solar heater either between the condenser and the expansion valve or between the compressor and the condenser or between the compressor and a reversing valve in a heat pump;   installing a replacement sensor directly after the solar heater;   coupling the replacement sensor to the controller;   modifying the controller to control the variable speed drive based, in part, on temperature or pressure data determined by the replacement sensor using a closed-loop control scheme.   
     
     
         16 . The method of  claim 15 , wherein the solar heater is plumbed between the condenser and the expansion valve. 
     
     
         17 . The method of  claim 15 , wherein the solar heater is plumbed between the compressor and the condenser. 
     
     
         18 . The method of  claim 15 , wherein the solar heater is plumbed between the compressor and a reversing valve in a heat pump. 
     
     
         19 . A refrigeration cycle device that operates with a refrigerant, the refrigeration cycle device comprising:
 a compressor comprising a variable speed motor, wherein the compressor is configured to increase the pressure of vapor refrigerant;   a variable-speed drive configured to vary speed and torque of the variable speed motor;   a first heat exchanger configured to cool and condense vapor refrigerant to liquid refrigerant;   an expansion valve configured to expand liquid refrigerant to vapor refrigerant; and   a second heat exchanger configured to heat vapor refrigerant;   a solar heater configured to heat the refrigerant using solar energy;   a sensor configured to determine a refrigerant heat or a refrigerant pressure, wherein the sensor is plumbed directly after the solar heater to detect the refrigerant heat or refrigerant pressure after the refrigerant is heated using solar energy;   a controller configured to control the compressor with a closed-loop control scheme using the variable-speed drive based, at least in part, on the refrigerant heat or pressure determined by the sensor.   
     
     
         20 . The refrigeration cycle device of  claim 19 , wherein the solar heater is plumbed between the first heat exchanger and the expansion valve. 
     
     
         21 . The refrigeration cycle device of  claim 19 , wherein the solar heater is plumbed between the compressor and the first heat exchanger. 
     
     
         22 . The refrigeration cycle device of  claim 19 , wherein the solar heater is plumbed between the compressor and a reversing valve in a heat pump. 
     
     
         23 . The refrigeration cycle device of  claim 19 , wherein the expansion valve has a predetermined operating pressure and wherein the controller is programmed to control the compressor so that the pressure at the sensor is the predetermined operating pressure of the expansion valve using a closed-loop control scheme. 
     
     
         24 . The refrigeration cycle device of  claim 19 , wherein the solar heater is plumbed in a location where the refrigerant is a liquid when the refrigeration cycle device is operating. 
     
     
         25 . The refrigeration cycle device of  claim 19 , wherein the solar heater is physically coupled to at least a portion of the refrigeration cycle device. 
     
     
         26 . The refrigeration cycle device of  claim 19 , wherein the solar heater is not physically coupled to any portion of the refrigeration cycle device. 
     
     
         27 . The refrigeration cycle device of  claim 19 , wherein the refrigeration device is a packaged HVAC system. 
     
     
         28 . The refrigeration cycle device of  claim 19 , wherein the refrigeration device is a split HVAC system. 
     
     
         29 . The refrigeration cycle device of  claim 19 , wherein the refrigeration device is a mini-split or ductless-split HVAC system. 
     
     
         30 . The refrigeration cycle device of  claim 19 , wherein the refrigeration device is a VRF or VRV HVAC system. 
     
     
         31 . The refrigeration cycle device of  claim 19 , wherein the refrigeration device is a refrigerator or cooler system. 
     
     
         32 . The refrigeration cycle device of  claim 19 , wherein the expansion valve has a predetermined operating pressure and wherein the controller is programmed to control the compressor so that the pressure at the sensor is the predetermined operating pressure of the expansion valve using a closed-loop control scheme.