Technical Papers and Presentations

Hot air is required in many engineering applications such as heating spaces and drying food. Solar air heater is used to heat air in an environmentally friendly way. The solar air heater consists of many components that are worthy to be studied to improve the performance of the solar air heater. In the present study, the influence of air space height, between absorber and glass cover, on the air outlet temperature, air mass flowrate, and the efficiency of solar air heater was experimentally and numerically investigated. The studied air spaces were 3, 5, 7, and 9 cm. Experimentally, four identical solar air heaters, each had different air space height, were built. Numerically, COMSOL Multiphysics^® simulation software was used. The implemented interfaces were Heat Transfer in Fluids and Laminar Flow. Surface-to-surface radiation and surface-to-ambient radiation were used. The properties of air flowing through the air solar heater were based on that available in Material Browser. A comparison was performed between the experimental and numerical results, and an acceptable agreement was found. The results showed that the highest air outlet temperature was gained with the narrowest space, 84 °C at 3 cm. The highest mass flowrate was gained with the widest space, 8.7 g/s at 9 cm. In addition, the highest efficiency was gained with the widest space, 47.3% at 9 cm.