The Study of Heat Exchange between Air and Snow Block with a Vertical Hole. The Effect of Air Flow Rate on Heat Exchange Characteristic.

Abstract

It is very important to use many kinds of natural energy resources to keep environment clean and to reduce the energy consumption. Many simple and skilful methods to utilize the natural energy have to be developed. The authors have been proposing to utilize snow stored till summer as one of the natural cold and clean energy resources. In this study, the authors investigated the characteristics of direct heat exchange between hot air and snow block with a vertical hole. This heat transfer model, so called as the snow cooling system, may be applied to various air-conditioning systems of conventional living room and so on. As the heat transfer process of this model is very complicated because the shape of the snow block changes by the progress of melting, the characteristics of the direct heat exchange were investigated by the experiment with a model of practical scale. The outlet air temperature through the snow hole and snow melting process were measured for various air flow rates at constant inlet air temperature 30°C. Experimental results show that the outlet air temperature from the snow cooling system was almost constant and enough lower to use for the actual air conditioning situations. Heat transfer coefficients on the snow surfaces of top plane, bottom plane and side wall of the snow hole were clear by those experimental results, and the correlative equations between the overall Nusselt number and the Reynolds number are presented for three surfaces mentioned above.