Refrigerated Storage Volume using Air Conditioner

Abstract

A conversion unit for an air conditioning system to cause it to act like the cooling unit of a refrigeration system comprises a frost detector, an A/C temperature control defeating mechanism and a control unit which operate together to force the range of operation of the air conditioning unit into the range of operation of a refrigeration unit. The conversion unit is particularly useful for providing low cost cooling systems for farmers in third world countries for keeping their produce fresh and safe, not to mention its use by all farmers around the world and by florists or others in need or desire of an economical refrigeration alternative. The present invention is also usable to provide inexpensive cooling to RV's and to refrigerated vehicles.

What is claimed is: 
     
         1 . A refrigerated storage volume, comprising:
 an air conditioning unit having a temperature sensor with a designed lower cutoff temperature controlling the operation of the air conditioner and fins through which air to be cooled is driven;   an insulated volume to be cooled to a refrigeration temperature below the designed lower cutoff temperature of the air conditioning unit, the air conditioning unit being mounted through a wall of the insulated volume with the cooling fins and temperature sensor inside the volume;   a conversion unit allowing the air conditioning unit to cool a volume to a refrigeration temperature below the designed lower cutoff temperature of the air conditioning unit, comprising:   a frost sensor mounted upon the fins of the air conditioning unit for detecting a temperature at which frost is likely to form on said fins of said air-conditioning unit;   a heater mounted in close proximity to the temperature sensor of the air conditioning unit, such that when the heater is operated the temperature sensor of the air conditioning unit senses a temperature above the designed lower cutoff temperature of the air conditioning unit;   a room sensor for sensing ambient temperature in the volume, disposed in the volume remote from the heater and the frost sensor on the fins of the air conditioning unit; and   a control unit having inputs coupled to the frost sensor and the room sensor and an output coupled to the heater, the control unit activating the heater when the room temperature sensor senses a temperature in the volume above a desired refrigeration temperature, and the control unit deactivating the heater when the frost sensor detects a temperature at which frost is likely to form upon the fins of the air conditioning unit.   
     
     
         2 . The refrigerated storage volume of  claim 1  in which said control unit further comprises an input for setting desired refrigeration temperature within the storage volume. 
     
     
         3 . The refrigerated storage volume of  claim 1  in which said control unit further comprises an input for setting a threshold temperature at which frost is likely to form on said fins. 
     
     
         4 . The refrigerated storage volume of  claim 1  in which said frost sensor is a temperature indicating probe. 
     
     
         5 . The refrigerated storage volume of  claim 1 , wherein the wherein the lower cutoff temperature is no less than 60° F. 
     
     
         6 . A conversion unit to adapt an air conditioning unit having a temperature sensor with a designed lower cutoff temperature controlling the operation of the air conditioner, and cooling fins through which air to be cooled is driven, the air conditioning unit being mounted through a wall of a volume with the cooling fins and temperature sensor inside the volume, the conversion unit allowing the air conditioning unit to cool the volume to a refrigeration temperature below the designed lower cutoff temperature of the air conditioning unit, said conversion unit comprising:
 a frost sensor mounted upon the fins of the air conditioning unit for detecting a temperature of the fins of the air conditioner at which frost is likely to form on said fins of said air-conditioning unit;   a heater mounted in close proximity to the temperature sensor of the air conditioning unit, such that when the heater is operated the temperature sensor of the air conditioning unit senses a temperature above the designed lower cutoff temperature of the air conditioning unit;   a room temperature sensor for sensing ambient temperature in the volume being cooled, disposed in the volume remote from the heater and the frost sensor on the fins of the air conditioning unit; and   a control unit having inputs coupled to the frost sensor and the room temperature sensor and an output coupled to the heater, the control unit activating the heater when the room temperature sensor senses a temperature in the volume above a desired temperature, and the control unit deactivating the heater when the frost sensor detects a temperature on the fins of the air conditioner at which frost is likely to form upon the fins of the air conditioning unit.   
     
     
         7 . The conversion unit of  claim 6  in which said control unit includes a display for displaying the ambient temperature from the room temperature sensor. 
     
     
         8 . The conversion unit of  claim 7  in which said display is selected from the group consisting of an LCD display and an LED display. 
     
     
         9 . The conversion unit of  claim 8  in which said control unit includes a means for setting the desired temperature. 
     
     
         10 . The conversion unit of  claim 6  in which said control unit includes a means for setting a threshold temperature on the fins of the air conditioner at which frost is likely to form upon the fins of the air conditioning unit. 
     
     
         11 . The conversion unit of  claim 6  in which the volume is a thermally insulated enclosure, the conversion unit and the thermally insulated volume forming a refrigerated storage volume in combination with the air conditioner. 
     
     
         12 . The conversion unit of  claim 6  in which said air conditioning unit is disposed through a wall in said volume with the cooling fins and temperature sensor within the volume. 
     
     
         13 . The conversion unit of  claim 6  in which said frost sensor is a temperature indicating probe. 
     
     
         14 . The conversion unit of  claim 6 , further comprising a second heater disposed internal to said device for controlling condensation therein. 
     
     
         15 . The conversion unit of  claim 14  in which power is supplied at distinct times to said heater and said second heater. 
     
     
         16 . The unit of  claim 6  wherein the lower cutoff temperature is no less than 60° F. 
     
     
         17 . A conversion unit for adapting a room or window air conditioning unit of the type that has cooling fins, a thermocouple, and a lower cutoff temperature of no less than 60° F., so as to cool a volume to less than the lower cutoff temperature, the unit comprising:
 means for setting and displaying a desired temperature that is lower than the cutoff temperature of the air conditioner; 
 means for sensing the temperature of the cooled volume; 
 means for heating the thermocouple of the air conditioner so as to cause the air conditioner to cool the volume to less than the lower cutoff temperature; 
 means for detecting the buildup of frost on the cooling fins; and 
 means for ceasing the heating of the thernmocouple when frost is detected on the cooling fins.