Airflow, heat and moisture transfers by natural convection in a refrigerating cavity

Abstract Experiment was carried out using a rectangular refrigerating cavity which can be more or less humidified and loaded with arranged cylinders. One of the vertical walls, made of aluminium, was kept at low temperature (+1 °C). The opposite wall made of double glass, involves heat transfer with the ambience (21 °C). The other walls were insulated so that 2-dimensional heat transfer and fluid flow was assured. These conditions are similar to those encounters inside domestic refrigerator. The influence of humidification was studied using a heated water vat which simulates evaporation in the vegetable box of a refrigerator. The measurement of air velocity (by particle image velocimetry, PIV), temperature (by thermocouple) and humidity (by hygrometry) was undertaken. It was found that water evaporation modifies significantly air velocity field since it leads to increase air velocity whatever the positions in the cavity. Temperature stratification was observed: high temperature at the top and low temperature at the bottom. The influence of water evaporation on air and cylinder temperatures is more pronounced at the bottom of the cavity. In presence of the water vat, the air absolute humidity varies slightly with the position in the cavity.