Design and Evaluation of Flat Plate Solar Water Heater under Iraq Climate

The increasing demand for water heating in buildings, industries, and hospitals shows the necessity of using alternative energy as fossil fuel sources decline. This study aims to design and simulate a flat plate solar water heater, analyze the impact of tube geometry and operating parameters, and evaluate the performance of an open-loop SWH by conducting experiments and using the CFD technique. The designed dimensions and materials of the absorber plate were used in CFD simulation and fabrication of the SWH. A CFD technique ANSYS-FLUENT has been used to simulate thermo-hydraulic laminar flow in SWH tubes. The experimental investigation of an open-loop solar water heating system comprises a flat plate absorber, hot and cold water tanks, a water circulation pump, and measuring devices. Experiments were conducted at different parameters effects. The numerical results were validated with experimental data under Iraq climate. The investigations at low Reynolds numbers show that as the tube length increases by 35% for the tube diameter of 10mm, the outlet temperature rises by 28% and 9% for the flow rate of 0.01L/min and 0.15L/min, respectively. Also, as the tube diameter decreases by 50% for the tube length of 3.21m, the outlet temperature increases by 28% and 6% for the flow rate of 0.01L/min and 0.15L/min, respectively. The greater outlet water temperature obtained in the Baghdad location is at a tilt angle of 40°. Heat transfer from the absorber plate to the flowing water is maximized by reducing the tube diameter, increasing the tube length and absorbing solar radiation.