Retrofittable air conditioner to refrigeration conversion unit

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, a heater 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.

1 . A device to adapt an air conditioning unit to a lower temperature of operation, said device comprising:
 a sensor for detecting the presence of frost on fins of said air-conditioning unit;   a heater for disposition adjacent to a temperature sensor for said air conditioning unit; and   a control unit, for activating said heater upon the condition that said sensor provides an indication that frost is not present on said fins.   
   
   
       2 . The device of  claim 1  in which said control unit includes a display for displaying temperature. 
   
   
       3 . The device of  claim 2  in which said display is selected from the group consisting of an LCD display and an LED display. 
   
   
       4 . The device of  claim 1  in which said control unit includes a means for setting desired temperature. 
   
   
       5 . The device of  claim 1  in which said control unit includes a means for setting a threshold for frost detection on said fins. 
   
   
       6 . The combination of the device of  claim 1  together with said air conditioning unit. 
   
   
       7 . The combination of  claim 6  further including a thermally insulated enclosure. 
   
   
       8 . The combination of  claim 7  in which said air conditioning unit is disposed through a wall in said enclosure. 
   
   
       9 . The device of  claim 1  in which said frost sensor is a temperature indicating probe. 
   
   
       10 . A device to adapt an air conditioning unit to a lower temperature of operation, said device comprising:
 a sensor for detecting the presence of frost on fins of said air conditioning unit;   a first heater for disposition adjacent to a temperature sensor for said air conditioning unit;   a second heater disposed internal to said device for controlling condensation therein; and   a control unit, for activating said first heater upon the condition that said sensor provides an indication that frost is not present on said fins.   
   
   
       11 . The device of  claim 10  in which power is supplied at distinct times to said first heater and said second heater. 
   
   
       12 . A method for operating an existing air conditioning unit having fins across which air is directed to cool it, so as to achieve a lower temperature of operation for said air conditioning unit, said method comprising the steps of:
 applying heat to a temperature sensor in said air conditioning unit;   sensing the presence of frost on said fins in said air conditioning unit; and   controllably adjusting the heat applied to said temperature sensor to produce continued operation without producing significant frost build up on said fins.   
   
   
       13 . The method of  claim 12  in which said steps are carried out by an adapter coupled to said air conditioning unit and connected thereto for supplying power to said adapter. 
   
   
       14 . A method for converting an existing air conditioner into a unit capable of operating as the core of a refrigeration system, said method comprising the steps of:
 thermally connecting a heater in an adapter to a temperature sensor of said air conditioner;   disposing a frost sensor from said adapter adjacent to fins in said air conditioner; and   electrically connecting said adapter to said air conditioner to supply said adapter with power for its operation.   
   
   
       15 . The method of  claim 14  in which said adapter includes a controller for controlling said heater so as to reduce frost build up on said fins.