DESIGN AND CONSTRUCTION OF A HYBRID SOLAR WATER HEATER FOR LOW-COST DOMESTIC WATER HEATING

Abstract

Domestic water heating is an important household energy demand, particularly during cold seasons and in regions where electricity and natural-gas supply can be interrupted or costly. This study presents the design and construction of a low-cost hybrid solar water heater that combines direct solar thermal heating with an electrically assisted heating stage powered by a solar panel. The prototype uses locally available materials, including a wooden frame, aluminum sheet, aluminum tubing, expanded polystyrene (thermocol) insulation, a transparent cover, rubber connectors, black matte coating, thermometers, and a nickel-chromium resistive heating element. The collector section is designed to expose the aluminum heat-transfer surface and tubing to solar radiation while the transparent cover reduces convective and radiative heat losses. The tubing is bent into a serpentine/U-shaped arrangement to increase the effective heat-transfer path and residence time of water in the collector. A photovoltaic-powered nickel-chromium element is incorporated as a supplementary heating mechanism, producing the hybrid configuration. The thesis reports that the system can warm water primarily through the direct solar collector, with additional heating supplied through the photovoltaic-assisted electrical element. The resulting prototype is intended as an inexpensive and readily repairable alternative to conventional gas- or grid-electric water heaters. Because the original thesis does not provide a complete time-resolved experimental temperature dataset, the present manuscript focuses on the design, construction, operating mechanism, and reported performance claims rather than introducing unmeasured numerical efficiency values. The work provides a practical foundation for subsequent controlled testing under different solar irradiance, flow-rate, ambient-temperature, and photovoltaic operating conditions.