The Effect of Sunflower Oil and Water on Thermal Storage Parameters of a Flat Plate Solar Water Heating Collector

Abstract

Solar thermal energy conversion by flat solar collectors can be used for water heating to a temperature of 80℃. However, the thermal performance of these solar collectors is very much affected by varying weather conditions. Heat retention can effectively be achieved by the use of thermal storage fluids like sunflower oil. The aim of the study is to assess the effects of sunflower oil and water on the thermal storage capacity parameters of a flat plate solar water heater. Specific objectives were to determine the effect of water and sunflower oil on the peak output temperature, heat removal factor, heat loss coefficient, and efficiency of the flat plate solar water heating systems. Flat plate solar water heating collectors containing sunflower oil and water as thermal storage fluids were designed and constructed for this study. The absorber plate was made of mild steel welded to galvanized iron riser pipes. The temperatures were measured using K-type thermocouples connected to a data logger and a computer. Simulation and theoretical modeling were done using KOLEKTOR 2.2 software, while experimental data computation and analysis were done using MATLAB. Research findings showed that sunflower oil and air attained a peak temperature of 75℃, while that of water was 65℃ from 12 noon to 3.30 pm. Sunflower oil has the longest stagnation (steady) temperature duration. Both experimental and theoretical results showed that sunflower oil has a higher removal factor FR and efficiency factor F1 than water. From the KOLEKTOR model, efficiency factor F1 values of sunflower oil, water, and air are 0.922, 0.916, and 0.818, respectively. Sunflower oil is also a better thermal storage fluid than water since it has a lower heat loss coefficient than water. Other studies have also shown that sensible heat storage media improve efficiency by reducing thermal losses. The information from this study would be useful for the effective utilization of intermittent solar energy for heating applications. Thus, reducing water heating expenses and conserving our environment.