Sustainable Development in Renewable Energy & its Future

Solar air heater is one of the basic equipment through which solar energy is converted into thermal energy. A solar air heater is a type of heat exchanger which transfers solar radiation into heat energy. Solar air heaters, because of their simple designing, are cheap and most widely used as a collection devices of solar energy. Solar air heaters are one of the simplest and cost effective solar energy utilization systems for various drying applications. The thermal efficiency of solar air heaters is found to be low due to low heat transfer coefficient on the air side. Attempts have been made to enhance the heat transfer rate from the absorber plate to air by using different roughness elements. Enhancement of heat transfer coefficient is achieved by providing artificial roughness, always goes with an increment of pressure drop and more pumping power is required. So, there is a need to optimize the system parameters to maximize heat transfer, while keeping the friction losses as low as possible.