Design and Construction of a Thermosiphonic Solar PhotovoltaicThermal Water Heating System

Abstract

The maximum electricity conversion efficiency of the Solar Photovoltaic panel is 8-18% under the Standard Test Condition (STC) temperature of 25°C. The atmospheric temperature of Sokoto, North-West Nigerian climatic condition is mostly about 30°C - 45°C, it incites 30°C - 80°C heat over the panel since black body of the PV panel observe more heat, and this temperature majorly affect the electrical efficiency of the panel.A thermosiphonic solar PV/T water heating system which could be used for domestic purpose has been designed constructed and tested using locally available materials. Solar energy is received by the PV surface which then utilize a small fraction of the incident solar radiation to produce electricity and the remainder is turned mainly into waste heat in the cells, this waste heat is utilized by attaching an oscillatory flow heat exchanger brazed to a copper sheet and adhered at the back of the PV panel to extract heat from the PV panel, thereby increasing its electrical efficiency, and an insulated casing is placed at the back of the heat exchanger to reduce heat loss to the environment. A cold and hot water tank is then integrated to the system so that water flows from the cold water tank to the heat exchanger, gets heated and flows into a hot water storage tank through thermosyphon principle. Maximum fluid output temperature, solar insolation, thermal and electrical outputs are 63.2oC, 957W/m2, 509.5W and 140W respectively, were obtained on a sunny day. This solar water heating system finds useful application and acts as a renewable energy resource in regions where there is abundant and consistent sunlight.