Study On The Performance And Optimazition Of The Latent Heat Storage System

As electronic industry and communication technology improves continually, the scale and number of the telecommunications base stations(TBSs) increase continually, resulting in the increase of the energy consumption in the TBSs where the energy consumption of air conditioning systems in the TBSs accounts for about 45% of the total energy consumption of TBSs. Therefore, decreasing the energy consumption of air conditioning systems in the TBSs becomes a popular research field. The phase change material(PCM) has the advantage of reusability, big energy storage density, constant temperature, and so on. It can be utilized to realize the “free use” of the natural cold resource or hot resource by the process of the storage and release of the latent heat. Meanwhile, it can be also used to decrease the distribution capacity and improve the operational efficiency by “peak load shifting”. Hence, it can be applied to lots of research fields. The latent heat storage system in the TBSs utilizes the active phase change energy storage technology and natural cold resource technology, reducing the excess heat in the TBSs effectively.This paper built the mathmetic model of the heat transfer process in the latent heat storage system, and used Matlab softmare to solve the model. The calculation results were compared with the experimental test data. The analysis results showed that during the energy charging mode, the relative errors of temperature differences in the water side and air side were 1.33% and 7.27%, respectively; during the discharging process, the relative errors of temperature differences in the water side and air side were 5.23% and 8.00%, respectively. This verifies the validity of the mathmetic model. In the basis of the study, the effect of the fan flow and pump flow on the performance of the system is analyzed.The latent heat storage system which used two different PCMs is studied, using the exergy efficiency and EER as the performance evaluation idexes. The influence of the phase change temperature and the unit of the energy efficiency of the first and second phase change energy storage module on the performance of the system were analyzed from the angel of the first and second law of thermodynamics.Five cities containing Haerbin(severe cold region), Jinan(cold region), Chengdu(mild region), Wuhan(hot summer and warm winter region), and Xiamen(hot summer and cold winter region) which could represent the typical climate regions of China was selected, and the operational cases of the latent heat storage system in these five cities were simulated. The effect of different phase change temperature and pump flow on the performance of the latent heat storage system was analyzed. For the building structure, indoor air heat released, and feather of the air conditioning system in the specific telecommunications base stations, using the annual electricity savings in different COP of the conventional air conditioning system as the optimal function and the phase change temperature and the pump flow rate as the optimal parameters, the genetic algorithm(GA) was utilized to optimize the performance of the latent heat storage system in the TBSs in the five cities which could represent the typical climate regions of China. The result shows that when COP is 3.5, the annual electricity savings in Haerbin, Jinan, Chengdu, Wuhan, and Xiamen increase by 1.5%、0.8%、1.2%、1.0%、1.1%, respectively.