Enhancing the coefficient of performance (COP) of mini refrigerators based on thermoelectric units (Peltier)

Abstract

Energy scarcity in the world and the pollutants resulting from excessive use of energy lead to an increase in global warming. There is a need to search for sustainable alternatives that use less energy to reduce environmental problems as well as alternatives to the use of Freon, which is harmful to the environment, one of the most dangerous pollutants, and increases the ozone hole. The current research aims to investigate the performance of thermoelectric refrigerators with different operating conditions. A portable thermoelectric refrigerator was developed for those living in remote areas of Egypt off the electrical grid (e.g., deserts). The designed refrigerator is based on the Peltier effect using Peltier units. The refrigerator is designed, manufactured, and experimentally tested. Several variables were studied in fast cooling systems for different conditions to minimize time, decrease the cooling temperature, and increase the coefficient of performance (COP) by the response surface methodology (RSM) model. The results reveal that the obtained maximum COP was 77.3%, at 4 V and 1.006 with a difference in cooling temperature (∆T) of 8°C. The highest ∆T was 26.4°C at 10 V, 9.149 A, 91.49 W and COP 11.2%. The optimum condition was cooling temperature 12.7°C, COP 51.4% at 4 V, 3.445 A by using 4 Peltier, according to Response surface methodology (RSM) includes optimization procedures for the settings of factorial variables by design expert 13, such that maximum ∆T was 20.3°C and maximum COP 49.576% with 4 volts, 4 no. of Peltier and current 3.601 A in the value range. The results reveal that the obtained determination coefficient for ∆T and the COP adjusted R2 and R3 values 0.9286 and 0.9603 respectively.