Thermal Energy and Exergy Analysis of Asphalt Solar Water Heater for Small Residences

The objective of this research is to study the energy efficiency and exertion of asphalt solar water heaters (ASWH) in transmitting solar heat through water pipes together with friction and energy destruction. One ASWH had a water flow rate of 0.02 kg/s, whereas the other had a flow rate of 0.04 kg/s. Each ASWH has a surface area of 0.5 m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, The asphalt has copper pipes buried 10 mm deep. Placed facing south at an angle of 13.5 degrees. The results shown that, the water flow rate 0.04 kg/s has relatively high the energy and exergy efficiencies. The energy and exergy efficiencies were changed from 28% to 60% and 3.2% to 11 %, respectively, depending on the water flow rate, asphalt temperature, and sun intensity. The water flow rate is important in estimating the internal convection coefficient and the Reynolds number for determining the friction effect in copper pipes varies with internal convection. The friction factors cause pressure loss and the exergy destruction caused by friction.