Study on the Optimun Operation of High Performance Cold Thermal Storage System Using Liquid Ice

1. 紧凑型液冰蓄热系统的设计与施工进行了家用紧凑型蓄热系统的设计与施工，确定了系统的最佳运行方式。实验系统主要由液冰的生产和储存单元、输送回路和消耗单元组成。液冰的生产和储存单元由冰箱、蒸发器和储罐组成。蒸发器安装在储罐内，表面涂有聚烯烃管。液态冰是通过在罐内冷却二元水溶液而产生的。罐内产生的液冰通过20m长的管路系统由循环泵导出至热负荷机组，冷能消耗后返回储罐。实验中，将系统的多种运行模式，即液态冰的生产时间、储存时间和消耗时间的组合作为试验参数。然后对制冷机的功率输入、热负荷、冰包系数进行了测量，确定了制冷机的最佳运行方式。结果与备注(1)在放热操作模式下，出口空气温度和放出的热量基本保持恒定，直至液冰中的冰粒完全融化。此外，在液体中的冰粒——冰融化后，仍有足够的冷却能力依靠水溶液的显热来维持运行。(2)在生产模式下长时间的运行会产生较大的冰包系数，同时降低了液冰的温度，使制冷机的性能下降。因此，综合考虑制冷机的输入功率、制冷量、散热效率和散热方式等因素，确定了本研究的最佳运行方式。

1. Design and construction of the compact scale liquid-ice thermal storage systemA design and construction of the compact scale thermal storage system for home-use have been carried out to determine the optimum operation mode of the system. The experimental system consists mainly of production and storage unit, transporting loop, and consumption unit of the liquid ice. Production and storage unit of the liquid ice consists of refrigerator, evaporator, and storage tank. The evaporator was installed in the storage tank with its surface being coated with polyolefin tube. Liquid ice was produced by cooling aqueous binary solution in the tank. Liquid ice, which was produced in the tank, is derived to the thermal load unit by the circulating pump through the piping system with 20m long, and then returns to storage tank after its cold energy consumed. In the kexperiment, a variety of operation modes of the system, namely the combination of the time of production, storage, and consumption of the liquid ice, were set as the test parameters. Then the measurements of power-input of the refrigerator, thermal load, and ice-packing factor were carried out, and then the optimum operation mode was determined.2. RESULTS AND REMARKS(1) In the heat release operation mode, both the exit air temperature and released heat were kept almost constant until the ice particles in the liquid-ice finish to melt. Furthermore, after the ice particles in the liquid-ice has melt, cooling capacity remains enough to keep the operation by the sensible heat of aqueous solution.(2) Long-time opration in the production mode produces much more ice packing factor, while it reduces the temperature of the liquid-ice yielding the reduction of the performance of the refrigerator. Therefore, by taking all the factors, namely, power input to the refrigerator, cooling capacity, efficiency o heat-release mode, into the account, the optimum operation mode in the present study has been determined.