EN: Editorial 110C: COP 25

Abstract

This work presents a numerical and experimental approach focused on design guidelines for hot-wall condensers applied to domestic refrigerators. To this end, seven refrigerators were manufactured with distinct condenser designs. The design parameters were the following: (i) adhesive tape (aluminum or polyethylene), (ii) tube outer diameter (4 or 4.76 mm), (iii) total length (10 or 11.5 m) and (iv) lay-out. An in-house mathematical model for hot-wall condensers was added to an in-house system simulation tool to predict the refrigerators performance. Experiments were conducted in a climate-controlled test chamber. It was found that the model predictions are close to the energy consumption measurements with deviations of the order of ±10%. It has also been found that the heat load is increased on average by 7.7% when a hot-wall condenser is added to the system. An extensive sensitivity analysis was also put forward, showing that the hot-wall condenser and thus the refrigerator performance is very much affected by the outer sheet thermal conductivity and thickness, but mainly by the tape thermal conductivity. The contact area between tube and outer sheet also plays a significant role in the heat transfer, meaning that a cheaper polymeric tape could be used if enough contact area is provided. Additionally, it has been found that there is a tube pitch which minimizes the energy consumption in despite of the condenser geometry.