DESIGN, CONSTRUCTION AND PERFORMANCE EVALUATION OF A PASSIVE SOLAR WATER HEATER
ABSTRACT
Solar energy being transmitted from the sun through space to earth by electromagnetic radiation must be converted to heat before it can be used in a practical heating or cooling system. Solar energy collectors, the devices used to convert the suns radiation to heat, usually consist of a surface that efficiently absorbs radiation and converts this incident flux to heat which raises the temperature of the absorbing material.There is the need for adequate research to be carried out on the solar heating system so as to make recommendations on the right design to improve it performance and save energy costs. The objective of this work is to provide energy for heating water for domestic and industrial use, to publicize the knowledge to potential users and for commercial purposes, to make relevant recommendations based on the outcome of the research so as to improve the efficiency of the solar water heating system. In this research work, solar water heating system has been designed and constructed using locally available materials. Solar energy is received by a flate plate collector consisting of an absorber plate made up of galvanized sheet with a length of 110 cm, a width of 80 cm and a thickness of 0.7 mm. The zigzag-pipe is fixed to the sheet and then painted dull-black., integrated with fluid carrying tubes, and place in an insulated casing with a trasparent glass cover having a storage tank integrated in the system. The radiation emmited by the absorber plate cannot escape through the glass, thus increasing it temperature. The water gets heated and flows into the storage tank through the thermosyphon principle.The system was tested in the month of August 2017. The maximum temperature of the heated water and collector surface temperature of 85 0C and 75 0C respectively, were recorded between the hours of 1:00 pm and 2:00 pm on a sunny day. This solar water heating system finds useful application in homes and industries. The solar water heater can be used in regions where there is abundant and consistent sunlight. Based on this research work, it is recommended that the insulation layer should be made up of styro-foam because it has greater ability to prevent heat loss and a separate tank be provided for the heated water.
