Medical Grade Freezer for Vaccines and Medications

Abstract

A medical grade cooler or freezer uses a Peltier system without the use of vapor compression refrigeration. An opening may be cut through a wall, for example, a top, bottom, rear or side wall, of the cooler or freezer and the Peltier device sealed within that opening with the hot side exposed outside of the cooler or freezer and the cold side exposed inside the cooler. When a voltage is applied to the Peltier device, the interior temperature of the cooler may be reduced. The Peltier devices can also be reversed by applying voltage in the opposite direction to remove heat from outside of the cooler and pump heat into the cooler or freezer.

What we claim is: 
     
         1 . A medical cabinet for cooling vaccines comprising:
 a cabinet having upstanding front wall and upstanding rear wall flanked by upstanding side walls enclosed by a top wall and bottom wall on their top edges and bottom edges, respectively, to define a cabinet volume;   at least one shelf dividing the cabinet volume into separate compartments;   a first Peltier thermoelectric device providing a first semiconductor plate across which a voltage is applied supported by at least one wall of the cabinet;   a second Peltier thermoelectric device providing a second semiconductor plate across which the voltage is applied supported by at least one wall of the cabinet;   a heat sink attached to at least one of the first and second Peltier thermoelectric devices; and   a fan attached to the heat sink and forcing air through the heat sink.   
     
     
         2 . The medical cabinet of  claim 1  wherein the upstanding front wall has at least one rectangular opening receiving at least one sliding drawer having a bottom wall surrounded by sidewalls terminating upwardly at a rectangular lip surrounding an upwardly exposed opening. 
     
     
         3 . The medical cabinet of  claim 2  further comprising sliding rails receiving the at least one drawer and permitting the at least one drawer to slide into and out of the at least one rectangular opening. 
     
     
         4 . The medical cabinet of  claim 3  wherein the sliding rails are supported on an inner surface of at least one of the upstanding side walls. 
     
     
         5 . The medical cabinet of  claim 1  wherein the at least one shelf is vented permitting airflow through the at least one shelf. 
     
     
         6 . The medical cabinet of  claim 1  wherein at least one of the upstanding front wall, rear wall, and upstanding side walls of the cabinet are covered with an insulation material. 
     
     
         7 . The medical cabinet of  claim 1  wherein the first and second Peltier thermoelectric devices extend through an opening in the top wall of the cabinet. 
     
     
         8 . The medical cabinet of  claim 1  wherein the heat sink and fan are positioned on an exterior of the cabinet. 
     
     
         9 . The medical cabinet of  claim 1  wherein the heat sink has multiple fins adapted to exchange heat with ambient air. 
     
     
         10 . The medical cabinet of  claim 1  further comprising electrical wiring communicating with at least one of the first and second Peltier thermoelectric devices and the fan and terminating at a standard automotive 12-volt connector. 
     
     
         11 . The medical cabinet of  claim 1  wherein an inner surface of at least one of the front wall, rear wall, and sidewalls is lined with a conductive material. 
     
     
         12 . The medical cabinet of  claim 1  further comprising at least one temperature sensor communicating with a microcontroller controlling a temperature of the cabinet volume. 
     
     
         13 . The medical cabinet of  claim 1  wherein the cabinet volume is approximately 5 to 9 cubic feet or less. 
     
     
         14 . A method of cooling vaccines comprising:
 providing a cabinet having upstanding sidewalls enclosed by a top wall and bottom wall on their top edges and bottom edges, respectively, defining a cabinet volume, and at least one shelf dividing the cabinet volume into separate compartments, a first Peltier thermoelectric device providing a first semiconductor plate across which a voltage is applied supported by at least one wall of the cabinet, a second Peltier thermoelectric device providing a second semiconductor plate across which the voltage is applied supported by at least one wall of the cabinet, a heat sink attached to at least one of the first and second Peltier thermoelectric devices, and a fan attached to the heat sink and forcing air through the heat sink;   inserting vials holding biologics into the cabinet volume; and   applying a voltage across the first and second Peltier thermoelectric devices.   
     
     
         15 . The method of  claim 14  comprising cooling the cabinet volume to a temperature of less than room temperature (20 to 22° C.). 
     
     
         16 . The method of  claim 15  comprising cooling the cabinet volume to a temperature of less than 10 degrees Celsius. 
     
     
         17 . The method  claim 14  further comprising inserting the vials into at least one sliding drawer having a bottom wall surrounded by sidewalls terminating upwardly at a rectangular lip surrounding an upwardly exposed opening removably insertable into the cabinet volume. 
     
     
         18 . The method of  claim 14  wherein 12 to 30 volts AC is applied across the first and second Peltier thermoelectric devices.