Systems and Methods for Operating a Refrigeration System

Abstract

Methods and systems for operating a refrigeration system for refrigerating a product are provided. A first temperature of the refrigerant downstream of a condenser and upstream of an evaporator may be obtained. A first pressure of the refrigerant downstream of the condenser and upstream of the evaporator may be obtained. A second pressure of the refrigerant downstream of the evaporator and upstream of a compressor and/or a temperature of the product being refrigerated may be obtained. A first valve, disposed between the condenser and the evaporator, may be controlled based on the first temperature and the first pressure to maintain a pre-determined cooling set-point for the refrigeration system. A second valve of the refrigeration system, coupled to the compressor, may be controlled based on the second pressure or the temperature of the product to optimize a capacity of a compressor of the refrigeration system.

1 . A method of operating a refrigeration system for refrigerating a product, the refrigeration system having a condenser, an evaporator downstream of the condenser, a compressor downstream of the evaporator, and a refrigerant flowing through the refrigeration system, the method comprising:
 obtaining, from a first transducer coupled to the refrigeration system, a first temperature of the refrigerant downstream of the condenser and upstream of the evaporator;   obtaining, from a second transducer coupled to the refrigeration system, a first pressure of the refrigerant downstream of the condenser and upstream of the evaporator;   obtaining, from a third transducer coupled to the refrigeration system, a second pressure of the refrigerant downstream of the evaporator and upstream of the compressor or a temperature of the product being refrigerated; and   controlling, via a processor communicatively coupled to the refrigeration system, a degree of opening of a first valve of the refrigeration system disposed between the condenser and the evaporator, based on the first temperature and the first pressure, to maintain a pre-determined cooling set-point for the refrigeration system, and a second valve of the refrigeration system coupled to the compressor, based on the second pressure or the temperature of the product, to optimize a capacity of the compressor.   
     
     
         2 . The method of  claim 1 , wherein controlling the first valve and controlling the second valve occur simultaneously. 
     
     
         3 . The method of  claim 1 , wherein obtaining the first temperature, the first pressure, and the temperature of the product or the second pressure occur simultaneously. 
     
     
         4 . The method of  claim 1 , wherein controlling the degree of opening of the first valve comprises controlling a degree of opening of an electronic stepper valve disposed between the condenser and the evaporator. 
     
     
         5 . The method of  claim 1 , further comprising calculating, via the processor, a current cooling level of the refrigerant leaving the condenser based on the first temperature and the first pressure, wherein controlling the degree of opening of the first valve of the refrigeration system comprises controlling the degree of opening of the first valve of the refrigeration system based on the calculated current cooling level. 
     
     
         6 . The method of  claim 5 , wherein controlling the degree of opening of the first valve of the refrigeration system comprises increasing or decreasing the degree of opening of the first valve of the refrigeration system when the calculated cooling level is different from the pre-determined cooling set-point. 
     
     
         7 . The method of  claim 5 , further comprising comparing, via the processor, the calculated cooling level of the refrigerant with the pre-determined cooling set-point, the pre-determined cooling set-point being the desired cooling level for the refrigerant when leaving the condenser, wherein controlling the degree of opening of the first valve of the refrigeration system comprises controlling the degree of opening of the first valve of the refrigeration system based on the comparing. 
     
     
         8 . The method of  claim 1 , wherein controlling the second valve comprises controlling a solenoid valve coupled to the compressor. 
     
     
         9 . The method of  claim 1 , further comprising comparing the obtained second pressure or product temperature with a pre-determined second pressure or product temperature set-point, wherein controlling the second valve of the refrigeration system comprises opening or closing the second valve based on the comparing. 
     
     
         10 . The method of  claim 9 , wherein controlling the second valve comprises energizing the solenoid valve when the second pressure or product temperature is less than the pre-determined second pressure or product temperature set-point, and de-energizing the solenoid valve when the second pressure or product temperature is greater than the pre-determined second pressure or product temperature set-point. 
     
     
         11 . The method of  claim 10 , further comprising suspending control of the first control valve when the solenoid valve is de-energized. 
     
     
         12 . The method of  claim 1 , wherein obtaining the second pressure or the temperature of the product comprises obtaining the second pressure of the refrigerant downstream of the evaporator and upstream of the compressor, and wherein controlling the second valve comprises controlling the second valve based on the second pressure of the refrigerant. 
     
     
         13 . The method of  claim 1 , wherein obtaining the second pressure or the temperature of the product comprises obtaining the temperature of the product, and wherein controlling the second valve comprises controlling the second valve based on the temperature of the product. 
     
     
         14 . The method of  claim 1 , further comprising adjusting, via the processor, a speed of an electric fan coupled to the condenser based on the first pressure. 
     
     
         15 . The method of  claim 1 , further comprising generating, via the processor, a visual indicator when a fault condition is detected in the refrigeration system. 
     
     
         16 . A refrigeration system for refrigerating a product, comprising:
 a condenser;   an evaporator disposed downstream of the condenser;   a compressor disposed downstream of the evaporator;   a first transducer disposed immediately downstream of the condenser, the first transducer configured to obtain a first temperature of a refrigerant downstream of the condenser and upstream of the evaporator;   a second transducer disposed immediately downstream of the condenser, the second transducer configured to obtain a first pressure of the refrigerant downstream of the condenser and upstream of the evaporator;   a third transducer disposed immediately downstream of the evaporator, the third transducer configured to obtain a second pressure of the refrigerant downstream of the evaporator and upstream of the compressor or a temperature of the product being refrigerated; and   a controller communicatively coupled to the first, second, and third transducers, the controller configured to control a first control valve disposed downstream of the condenser and upstream of the evaporator based on the obtained first temperature and the first pressure to maintain a pre-determined cooling set-point, the controller configured to control a second control valve coupled to the compressor based on the obtained second pressure or the temperature of the product to optimize a capacity of compressor.   
     
     
         17 . The refrigeration system of  claim 16 , wherein the first control valve comprises an electronic stepper valve configured to reduce the pressure of the refrigerant. 
     
     
         18 . The refrigeration system of  claim 16 , wherein the second control valve comprises a solenoid valve configured to load or unload the compressor. 
     
     
         19 . The refrigeration system of  claim 16 , further comprising: a fan arranged to pull a refrigeration medium across the condenser; and a fan drive configured to control a speed of the fan, wherein the controller is configured to control the fan drive based on the obtained first pressure. 
     
     
         20 . The refrigeration system of  claim 16 , further comprising a hand-held device communicatively coupled to the controller, the hand held device configured to allow a user to remotely monitor the refrigeration system. 
     
     
         21 . The refrigeration system of  claim 16 , wherein the controller is configured to calculate a current cooling level of the refrigerant downstream of the condenser and upstream of the evaporator based on the obtained first temperature and first pressure, and wherein the controller is configured to control the first valve of the refrigeration system based on the calculated cooling level. 
     
     
         22 . The refrigeration system of  claim 21 , wherein the controller is configured to compare the current cooling level of the refrigerant with the pre-determined cooling set-point, the pre-determined cooling set-point being the desired cooling level for the refrigerant when leaving the condenser, and wherein the controller is configured to control the first valve of the refrigeration system based on the comparison. 
     
     
         23 . The refrigeration system of  claim 16 , wherein the controller is configured to compare the obtained second pressure or temperature with a pre-determined second pressure or temperature set-point, and wherein the controller is configured to control the second control valve of the refrigeration system based on the comparison. 
     
     
         24 . The refrigeration system of  claim 23 , wherein the controller is configured to energize the solenoid valve when the obtained second pressure or temperature is less than the pre-determined second pressure or temperature set-point, and de-energize the solenoid valve when the obtained second pressure or temperature is greater than the pre-determined second pressure or temperature set-point. 
     
     
         25 . A method of operating a refrigeration system for refrigerating a product, the refrigeration system having a condenser, an evaporator downstream of the condenser, a compressor downstream of the evaporator, and a refrigerant flowing through the refrigeration system, the method comprising:
 obtaining, from a first transducer coupled to the refrigeration system, a first temperature of the refrigerant downstream of the condenser and upstream of the evaporator;   obtaining, from a second transducer coupled to the refrigeration system, a first pressure of the refrigerant downstream of the condenser and upstream of the evaporator;   obtaining, from a third transducer coupled to the refrigeration system, a second pressure of the refrigerant downstream of the evaporator and upstream of the compressor or a temperature of the product being refrigerated; and   controlling, via a processor communicatively coupled to the refrigeration system, a degree of opening of an electronic stepper valve disposed between the condenser and the evaporator, based on the temperature and the pressure, to maintain a pre-determined cooling set-point for the refrigeration system, such that the evaporator is flooded with liquid refrigerant, or controlling, via a processor communicatively coupled to the refrigeration system, a solenoid valve coupled to the compressor, based on the pressure or the temperature of the product, to optimize a capacity of the compressor.   
     
     
         26 . The method of  claim 25 , further comprising calculating, via the processor, a current cooling level of the refrigerant leaving the condenser based on the temperature and the pressure, wherein controlling the degree of opening of the electronic stepper valve of the refrigeration system comprises controlling the degree of opening of the electronic stepper valve based on the calculated current cooling level. 
     
     
         27 . The method of  claim 26 , wherein controlling the degree of opening of the electronic stepper valve of the refrigeration system comprises increasing or decreasing the degree of opening of the electronic stepper valve of the refrigeration system when the calculated current cooling level is different from the pre-determined cooling set-point. 
     
     
         28 . The method of  claim 26 , further comprising comparing, via the processor, the current cooling level of the refrigerant with the pre-determined cooling set-point, the pre-determined cooling set-point being the desired cooling level for the refrigerant when leaving the condenser, wherein controlling the degree of opening of the electronic stepper valve of the refrigeration system comprises controlling the degree of opening of the electronic stepper valve of the refrigeration system based on the comparing. 
     
     
         29 . The method of  claim 25 , further comprising adjusting, via the processor, a speed of an electric fan coupled to the condenser based on the temperature and/or pressure. 
     
     
         30 . The method of  claim 25 , further comprising comparing the obtained second pressure or the temperature of the product with a pre-determined second pressure or product temperature set-point, and wherein controlling the solenoid valve of the refrigeration system comprises controlling the solenoid valve based on the comparing. 
     
     
         31 . The method of  claim 30 , wherein controlling the solenoid valve comprises energizing the solenoid valve when the pressure or temperature is less than the pre-determined pressure or temperature set-point, and de-energizing the solenoid valve when the pressure or temperature is greater than the pre-determined pressure or temperature set-point. 
     
     
         32 . The method of  claim 25 , wherein obtaining the second pressure of the refrigerant or the temperature of the product comprises obtaining the second pressure of the refrigerant, and wherein controlling the solenoid valve comprises controlling the solenoid valve based on the second pressure of the refrigerant. 
     
     
         33 . The method of  claim 25 , wherein obtaining the second pressure of the refrigerant or the temperature of the product comprises obtaining the temperature of the product, and wherein controlling the solenoid valve comprises controlling the solenoid valve based on the temperature of the product.