The effect of radiation shields around the air condenser and compressor of a refrigerator on the temperature distribution inside it

Abstract

In almost all domestic refrigerators-freezers all components are assembled in the same relative position since several years ago. It is also known that the condenser releases heat at high temperatures (first law of thermodynamics) as well as the compressor. This heat is rejected to the environment in almost all practical situations partially by natural air convection. However, part of it is due to thermal radiation that causes an overheating of the refrigerator-freezer surfaces adjacent to those equipments. As a consequence there are more heat gains to the refrigerator-freezer through these surfaces and hence higher air temperatures inside. This paper describes how a simple technique can be very useful in order to minimize that part of heat transfer by radiation. The improvement is achieved by placing a radiation shield - a sheet of aluminium foil - over the surfaces close to the condenser and the compressor. For validating this technique a refrigerator-freezer was monitored with thermocouples for the measurements of the inside air temperatures in two situations: with and without the radiation shield. Results show that with this practice the average inside air temperatures in the refrigerator-freezer could decrease to about 2 K. An available commercial code was used in order to simulate the air temperature distribution and air velocities inside the refrigerator cabinet in both situations. Results from the experimental apparatus and from simulations show that there is a good agreement between them which validates the experiments carried out. Also an available commercial code, the Fluent, was used to simulate the internal air temperature in both situations. (c) 2006 Elsevier Ltd and IIR.