الفهرس 
BRIEF BACKGROUND ABOUT THERMAL ENERGY STORAGEOnly 14 pages are availabe for public view
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Abstract
Due to climatic change, thermal loads in buildings increase. Cooling thermal energy storage could become one of the important solutions to manage peaks electrical power imbalance between daytime and nighttime. This kind of storageuses off-peak power to provide cooling capacity by extracting heat from a storage medium. However, there are few studies specifying the correct phase change material (PCM) material to apply in each applications and the optimal quantity to be used. This study deals with the experimental investigations and optimization of thermal storage system using phase change material (PCM). In the present study, A comparison between natural PCM–coconut oil with melting temperature ranges 20-24°C. And polyethylene glycol with melting temperature range 17-20°C when they were filled inside copper spherical capsules was done. These PCM uses in air conditioning room in desert weather. A test unit is built in the Solar Energy Department; the National Research Center (N.R.C) Egypt was used in this study. Experiments using coconut oil with different thermal storage conditions are carried out. The experimental apparatus consists of mechanical cycle (the refrigeration cycle), air cycle, brine cycle and spherical capsules. The effects of the initial temperature of heat transfer fluid (HTF) during charging and discharging processes on the amount of thermal energy storage charge and ambient temperature on discharge time investigated. Effect of ambient temperature on room temperature during discharging process. The relation between the ambient temperature and the room temperature. The effects of using mix air (fresh air and return air) investigated. The efficiency of the system was calculated. A correlation developed, to predict the air room temperature from the ambient air temperature. Comparison between using coconut oil & poly ethylene glycol as well as comparison between latent heat storage & sensible heat storage are done. The present study enhances skills for experimental work in the field of heat transfer and thermal energy storage and it is also useful for teaching and training of many courses such as heat transfer, thermal equipment, fluid dynamics, thermal energy storage, refrigeration and air conditioning. Results showed that during discharging processes: using the total of return air leads to the increase of the accumulated stored thermal energy, the system efficiency increases by using total return air, using PCM (poly ethylene glycol) with 17-20oC melting range is the better than PCM (coconut oil) with 20-24oC melting range, the efficiency of latent heat storage system (polyethylene glycol) better than sensible heat storage system by 20% at the same ambient temperature and applying the system on the actual building saving 600000 L.E in initial cost and 59160 KW/year in running cost.