DEVELOPMENT OF THERMOELECTRIC REFRIGERATOR

Abstract

This research was aimed at developing a thermoelectric refrigerator. This thermoelectric refrigeration is with the aim of encouraging a local and indigenous thermoelectric industry and to ameliorate the harmful effect of Chloroflurocarbons (CFCs) refrigerants on the ozone layer. Thermoelectric refrigerator is a device that is able to remove heat, from the food items charged into a refrigerating chamber; through the electrical energy supplied to its module. The heat removed is deposited at the hot heat exchanger outside the refrigerating chamber. The capacity of the prototype designed is 30 W, using electrical energy of 12 V and current of 2.5 A. The module used to produce this capacity is (type inbc I- 127. 05) a single stage of size 40 mm by 40 mm by 4.0 mm with a transformer of 300 turns in primary winding and 15 turns in secondary winding, using a primary resistor of 1846Ω and 4.8 Ω as its secondary resistor. The heat exchangers adopted are: finned rectangular Aluminum Alloy hot heat exchanger (135 mm long, 102 mm wide and 15 mm high) and a square block Aluminum Alloy Cold heat exchanger (43 mm long, 43 mm wide and 25 mm high), instead of condenser and evaporator used in vapour compression system. The experimental results showed that with the aid of the module and the heat exchangers adopted in the system developed it would cool food items such as Tomato (153g) and Banana (1OOg), from 29°C to 4°C within four hours of cooling using fruits samples such as Banana, Tomato and Lemon. Moreover, there was no further heat removal observed after the fruits were cooled for four hours. The optimum coefficient of performance (COP) was 0.76 at 2.5A electric current supplied to the thermoelectric module.