Apparatus for controlling relative humidity in a container

Abstract

In one embodiment, the invention provides a refrigeration system having a compressor configured to compress a refrigerant gas and a condenser fluidly coupled to the compressor to receive compressed refrigerant gas from the compressor, the condenser configured to condense the refrigerant gas. In addition the refrigeration system includes a heat exchanger having a first section fluidly coupled to the compressor, and a second section fluidly coupled between the condenser and the compressor, wherein the first section receives compressed refrigerant gas from the compressor, and wherein the second section receives condensed refrigerant from the condenser, evaporates the refrigerant, and delivers the evaporated refrigerant to the compressor.

1 . A refrigeration system comprising:
 a compressor configured to compress a refrigerant gas;   a condenser fluidly coupled to the compressor to receive compressed refrigerant gas from the compressor, the condenser configured to condense the refrigerant gas;   a heat exchanger having a first section fluidly coupled to the compressor, and a second section fluidly coupled between the condenser and the compressor, wherein the first section receives compressed refrigerant gas from the compressor, and wherein the second section receives condensed refrigerant from the condenser, evaporates the refrigerant, and delivers the evaporated refrigerant to the compressor.   
     
     
         2 . The refrigeration system of  claim 1 , wherein the first section receives condensed refrigerant from the condenser, evaporates the refrigerant, and delivers the evaporated refrigerant to the compressor in a first mode of operation, and wherein the first section receives compressed refrigerant gas from the compressor in a second mode of operation. 
     
     
         3 . The refrigeration system of  claim 2 , wherein the refrigeration system operates in the first mode of operation when the temperature of the container is below a temperature lower limit, and wherein the refrigeration system operates in the second mode of operation when the temperature of the container is above a temperature upper limit and the relative humidity of the container is above a humidity upper limit. 
     
     
         4 . The refrigeration system of  claim 3 , wherein the refrigeration system includes humidity sensor for sensing the relative humidity of the container, and wherein the refrigeration system includes a temperature sensor for sensing the temperature of the container. 
     
     
         5 . The refrigeration system of  claim 4 , further comprising a first valve fluidly coupled between the compressor and the first section. 
     
     
         6 . The refrigeration system of  claim 5 , further comprising a second valve fluidly coupled between the condenser and the first section. 
     
     
         7 . The refrigeration system of  claim 6 , further comprising a controller operably coupled to the first valve, the second valve, the humidity sensor, and the temperature sensor, wherein in the second mode of operation the controller opens the first valve when the temperature sensor senses that the temperature of the container is above a temperature upper limit and the humidity sensor senses that the relative humidity of the container is above a humidity upper limit. 
     
     
         8 . The refrigerant system of  claim 7 , wherein in the second mode of operation the controller closes the second valve. 
     
     
         9 . The refrigerant system of  claim 7 , wherein in the first mode of operation the controller closes the first valve and opens the second valve such that the first and second sections receive condensed refrigerant from the condenser, evaporate the refrigerant, and deliver the evaporated refrigerant to the compressor. 
     
     
         10 . A method of operating a refrigeration system, the method comprising:
 compressing a refrigerant with a compressor;   condensing compressed refrigerant gas from the compressor in a condenser;   receiving into a first section of a heat exchanger compressed refrigerant gas from the compressor;   evaporating condensed refrigerant from the condenser in a second section of the heat exchanger; and   delivering the evaporated refrigerant from the second section to the compressor.   
     
     
         11 . The method of  claim 10 , further comprising evaporating condensed refrigerant from the condenser in the first section and delivering the evaporated refrigerant from the first section to the compressor in a first mode of operation, and receiving into the first section compressed refrigerant gas from the compressor in a second mode of operation. 
     
     
         12 . The method of  claim 11 , wherein evaporating condensed refrigerant from the condenser in a second section of the heat exchanger, and delivering the evaporated refrigerant from the second section to the compressor in both the first and second modes of operation. 
     
     
         13 . The method of  claim 11 , further comprising operating in the first mode of operation when the temperature of the container is below a temperature lower limit, and operating in the second mode of operation when the temperature of the container is above a temperature upper limit and the relative humidity of the container is above a humidity upper limit. 
     
     
         14 . A method of operating a refrigeration system, the method comprising:
 measuring a relative humidity of a container;   comparing the measured relative humidity to a humidity set point;   operating evaporator fans of a refrigeration system when the measured relative humidity is above the humidity set point.   
     
     
         15 . The method of  claim 14 , further comprising comparing the measured relative humidity to a elevated humidity set point, and operating an electric heater of the refrigeration system and the evaporator fans when the temperature of the container is above the elevated humidity set point. 
     
     
         16 . The method of  claim 14 , further comprising operating an electric heater of the refrigeration system if operation of the evaporator fans alone is insufficient to lower the relative humidity below the humidity set point. 
     
     
         17 . The method  claim 16 , further comprising operating the evaporating fans for a period of time when the measured relative humidity is above the humidity set point, and operating the electric heater after the period of time if operation of the evaporator fans alone is insufficient to lower the relative humidity below the humidity set point. 
     
     
         18 . The method of  claim 14 , further comprising operating the evaporator fans while not operating a compressor of the refrigeration system.