THE EXPERIMENTAL STUDY OF HEAT TRANSFER AND DYNAMIC CHARACTERISTICS OF DIRECT EVAPORATIVE INTERNAL-MELT ICE-STORAGE SYSTEM

摘要

The direct evaporative internal-melt ice-storage air conditioning is an important branch of the ice-storage technology. Its working principle is: during the charging process the coils in ice-tank play as an evaporator to chill the water into ice, while during the discharging process it works as a subcooler to further reduce the refrigerant temperature at the downstream of condenser. By this process, the full-load operating efficiency of the refrigeration system can be greatly improved and the initial capacity of the air-conditioning system can be reduced as well. In this paper, the experiments were carried out to investigate the heat transfer characteristics and control principle during the icing and melting processes. The tests were based on an inverter air-conditioner system The Nusselt number is measured along the coils for the charging process, and the correlations of Nusselt number were obtained as a function of mass quality and the ice layer thickness. The dynamic characteristics of the system about the charging process and discharging process were studied and the performance curves of the both processes were obtained. Experimental results show the power load shift rate of the experimental system achieves about 23%.