Design, Construction and study of performance of a flat-plate solar heater for winter air conditioning of a small residential building in Bangladesh

Abstract

Rising costs of conventional fuels, increasing energy demand, concerns over climate change and pollutants resulted from burning fossil fuels have increased the interest in various renewable energy technologies. The energy demand associated with heated air for different sectors is quite significant. Solar air heaters have been developed with the aim of reducing the demand for conventional fuels. This Thesis presents design and technical evaluation of solar air heating system on a small residential building in Bangladesh for winter air conditioning. It is estimated that for heating of 3m x 3m x 3.5m of room, a collector of 1.5m2 is needed with proper insulation of 2 inch thick Fiber glass. For the surface coating (generally black) on a mild steel sheet a selective coating system is suggested. For the distribution of air in the conditioned space a blower of Pressure 55mm (water), 1400 RPM, Frequency 50Hz, air velocity of 12 m/s and air capacity of .4 m3/s is used. A double glazing system is used to minimize the heat losses from the collector plate, which occur due to convection and radiation. The experimental work was performed beside the middle workshop, Mechanical Engineering Department, Islamic University of Technology under Gazipur prevailing weather conditions during the summer months August and September. Data were collected on half an hour interval from 9.00 am to 5.00 pm. As the ground was flat, the collector was proposed to be tilted with 23.5°. The outlet, Tout, and the inlet, Tin, temperatures were measured by using T- type thermocouples and the global solar radiation incident on an inclined surface was measured by using a Pyranometer.