ICT2014 Abstracts

The traditional approach to determine the optimum current for thermoelectric cooling assumes that the refrigeration chamber is insulated and has no thermal resistance to dissipate heat from a thermoelectric module.  As a result, the minimum temperature occurs when Peltier cooling is matched with parasitic heat transfer and Joule heating.  In real application, the minimum temperature happens when heat addition from environment is matched with heat extracted by a thermoelectric module, and the optimum current differs from the value anticipated by the traditional approach.  Hence, the consideration for insulation and thermal resistances via thermoelectric module should be made to achieve desirable cooling performance/refrigeration temperature.  This paper presents a modeling approach to determine optimum current as well as optimum geometry for a small solar (PV) powered refrigerator used as a vaccine delivery system for developing communities.  The model is derived from three energy conservation equations for temperatures at both ends of the thermoelectric materials within a module as well as the refrigeration chamber temperature.  A prototype was built to provide experimental evidence for the modeling approach.  It was found that no optimum thermal resistance values were found as the minimum temperature monotonously decreases with increasing insulation thermal resistance and increasing heat dissipation ability at the hot side of the module. Hence, a compromise between cost/size and performance needs to be made.  This study provides a sensitivity analysis of insulation on cooling performance so that maximum cooling performance per kilogram of insulation can be reached.