The purpose of this study is to improve the cooling performance of single and cascade refrigeration systems using thermoelectric modules. The system consists of a heat sink, fan, and thermoelectric module. The operating parameters considered in this study include power distribution between the first-and second-stage thermoelectric modules, air flow, and variable condensing unit. The cooling capacity increased with decreases in the temperature difference between hot and cold surfaces, but decreased with increases in the condensing temperature. The COP decreased with increasing electric power of the thermoelectric module because of the increased Joule heat. The cooling performance improvement using the thermoelectric module is represented by the freezer temperature.

A thermoelectric module is a device, which can transfer heat from one surface to another surface when a current is applied. A cooling system employing the thermoelectric module is generally known as a thermoelectric cooling system. A thermoelectric cooling system has no moving parts and does not require any refrigerant, so they are environmentally friendly, inherently reliable, and virtually maintenance free. In this study, a numerical analysis for optimization of a thermoelectric cooler is presented. A single-stage system, cuboids type twostage system and pyramid type two-stage system are analyzed concerning maximum cooling capacity. For two-stage thermoelectric systems, which are composed of two thermoelectric modules, the optimum ratio of current for each stage is analyzed theoretically. The cooling load and heat sink design are also analyzed to optimize the cooling capacity. When the temperature of the hot side of the thermoelectric module was fixed for all systems, the pyramid type twostage system showed an approximately 10.48% higher cooling capacity than that of a single system. The method to improve the performance of the pyramid type two-stage system was suggested by reducing the wasted area of the module surface.