The available statistics reveal that a significant portion of the total electrical energy in different communities is used for various heating and cooling purposes and refrigeration in the domestic and industrial sectors, which includes cooling systems in critical areas such as the food and pharmaceutical industries. In this work, air-to-air thermoelectric cooling systems have been analyzed. Experimental and numerical attempts have been made to evaluate the influence of the base thickness size of external heat exchanger on cooling performance of refrigerator. In addition, the cooling system has been operated in different working conditions and the effect of cooling fan velocity on the Coefficient of Performance (COP) value was presented. It was found revealed that, the temperature of the cooling chamber for 4.5 mm thickness dropped to 11.57 °C, while this temperature was 9.93 °C for 1.5 mm thickness. Considering the final temperatures, there was a 14% difference by reducing the thickness from 4.5 mm to 1.5 mm for the case of Vair = 7.5 external fan speed. For the numerical approach, ANSYS Fluent 16.0 software was utilized to analyze the structure of airflow inside and outside of the refrigerator in detail. As a result of Computational Fluid Dynamics (CFD) simulation temperature distribution and air velocity contours have been obtained and achieved results were discussed.