Practical Investigation for Water Solar Thermal Storage System Enhancement Using Sensible and Latent Heats in Baghdad-Iraq Weathers

Abstract

Solar power is a clean and sustainable energy,but the intensity of solar irradiation is unstable due to the change of season, weather, day and night. The period of the sunshine does not coincide with the time of the hot water consumption generally. The hot water consumption in family houses is generally bigger in the evening and in the morning, so it is necessary to store the utilized energy. The collectors transform but not store the solar energy. The storage is accomplished in a storage tank. The heat storage system can be used as a buffer to mitigate the fluctuation of solar incidence.The present study summarizes the investigation of improving thermal energy storage extracted from solar heater and use for domestic purpose. Two materials were used to improve heat storage inside the tank. Pebbles were used as a sensible store medium. The second material was paraffin wax which stores heat as latent heat. The two materials were stuffed in ten copper pipes (1 in dia). The storage energy of each material was compared to an ordinary conventional solar heater. The tests were conducted in Baghdad-Iraq wintertime (December-2012, January and February-2013).The two materials improved the storage efficiency of system and increased the hours of storage, butthe phase change materials (PCMs), as latent heat storage is more efficient than sensible heat storage. Paraffin wax provides many advantages, as it has high storage density and the isothermal nature of the storage process. It increases the time of storage and preserve water temperatures in case of no water drawl.