تجزیه و تحلیل عملکرد ارائه شده در سیستم ذخیره سازی حرارتی مایع - یخ برای عملکرد بهینه

For the purpose of determining the optimum operation condition of liquid-ice thermal storage system, the performance analysis has been carried out. The target system was consisted of refrigerator, its auxiliary devices, liquid-ice production device, piping system, and thermal load section. The system performances were widely investigated analytically for the variety of operation conditions including the cycle performance of a refrigerator. The optimum operation condition of the liquid-ice thermal storage system from the viewpoint of coefficient of performance and the performance of heat release were discussed.

Recently, for the purpose of energy saving and normalization of the difference of electric power demand among the seasons, both the research works and the actual usage of the cold thermal storage system have been increasing [1] and [2]. Liquid ice is regarded as a mixture of fine ice particles and some kind of liquid such as aqueous binary solution. Due to its high responsibility to the load change and its good portability, liquid ice is considered to be good as cold thermal storage materials for the future. A number of research works on the actual system including its production, melting [3], and transportation characteristics have been carried out. However, it seems that there may be few studies on the performance of the cold thermal storage system and its appropriate operation conditions. In the present study, liquid-ice cold thermal storage system was constructed, and the simulation investigated the effects of the operation mode of the system such as the combination of the ice-storage time and its release time on the system performance.

The system performance of liquid-ice cold thermal storage system has been carried out to determine the appropriate operation condition of the system. The effects of operation mode and initial concentration of aqueous solution on the system performance was investigated. The following conclusions were obtained within the parameter range of the present study. (1) The present simulation model using heat balance has been proven to be capable enough to describe the performance characteristics of liquid ice thermal storage system. We have investigated only the effect of operation mode, though, it is possible to predict and to estimate the performance of such a system in advance. (2) The coefficient of performance COP was almost the same for three operation modes in the present study, while the performance of heat release mode POR showed the tendency to decrease with increase of running time of storage time. (3) The present results of the system simulation may suggest the possibility to obtain an optimum operation condition such as a running time of thermal storage in a day among the operation mode shown in the present simulation. Judging from the results in the present simulation, the operation mode ‘A’ with low concentration of solution might be the most favorable in the present target system.