ABSTRACT
Domestic refrigerator works on vapour compression refrigeration principle with isobutane as a refrigerant. The heat from the refrigerated space is carried away by the refrigerant and is rejected into the atmosphere by the condenser. In earlier domestic refrigerators the condenser coil should be placed outside the refrigerator wall. To avoid any damage to the condenser coils while in transportations, it is embedded in the sidewalls of insulation, which is referred to as a hot-wall condenser. In hot-wall condenser, the tube surface is supported with a galvanized plate and an aluminium foil is used as an adhesive tape, which holds the tube in place. The heat rejected from the hot-wall condenser to the atmosphere is very small. In such a refrigerator, the average heat flux is within the range of 135 W/m2 to 142 W/m2 and the temperature gradient along the surface of the hot-wall condenser is in the range of10 K/m to the 43 K/m. The hot-wall condenser additionally increases the heat load of about 28 W. In the present research, the model is presented in order to enhance the rate of heat transfer from condenser tube to the metallic wall of the refrigerator; the condenser tube is supported with a hemispherical cross-sectioned plate to increase the contact surface. To carry out the heat transfer analysis with such a modified arrangement the steady-state, analytical modelling and a two-dimensional simulation of a hot-wall condenser is carried out. The simulation results show 9.3% improvement in heat transfer rate through walls and 50% drop in polystyrene surface temperature.
