A Review on Augmentation of Convective Heat Transfer Techniques in Solar Water Heating

Abstract

Solar water heating system is an effective technology for converting solar energy into thermal energy. According to the ministry of petroleum and natural gas, approximately 42% of refined crude oil is used in industrial and commercial applications for process heating. Fossil fuel is the main energy source which is depleting continuously. Solar energy is environment friendly energy source, which can full fill energy demand. Solar water heaters are most popular in domestic as well as industrial sector due to its ease of operation and simple maintenance. Extensive work is going on to improve the convective heat transfer, thermal efficiency of solar water. Passive techniques like use of Nano fluid, twisted tape, Phase Changing Materials (PCM) are used to augment convective heat transfer. These techniques enhance thermal performance of solar water heating system significantly. This paper reviews the various techniques to enhance the thermal efficiency of solar water heaters. In addition to this, a detailed discussion and limitations of existing research have made. From this discussion research gaps are identified and possible modifications are suggested.