Experimental Study of the Dynamic Heat Storage Process by Jetting Water in Direct-evaporation Ice-storage Air-conditioning

A new ice storage tank which is consisted of coil heat exchanger, water injector and water tank is presented in the paper. The injector is a self-made device to jet high velocity water stream to disturb the water in the tank in order to enhance heat transfer of water. In this paper, a direct-evaporation ice-storage air conditioning system equipped with the new ice storage tank had been reconstructed under a 3HP compressor. In order to investigate the effect of injector, experimental measurements of water-temperature distribution in the tank, ice thickness and evaporation temperature were recorded and compared in the static and dynamic ice storage process under room condition (thy bulb temperature was 25 degrees C/ wet bulb temperature was 20 degrees C). The results showed that with this help of injector, the water temperature was more uniform, and the largest temperature difference in height direction was less than 0.1 degrees C and ice was observed to form outside of tube later. The local heat transfer coefficient of the water-ice at the coil surface increase 300% while the injector was adopted. As a consequence, the average evaporation temperature of refrigerant in dynamic mode was improved 3 degrees C than the static one, so electric power spent on the system had been saved to some extent.