ign and Control Analysis Of An Automatic Active Domestic Solar Water Heating System

Abstract

Solar water heating technology is one of the cost-effective ways of heating water in residential and public buildings. This study presents the design technique for an automatic active domestic solar water heating system (ADSWHS) to meet the hot water demand for a residence in Wum (10.43°E, 6.23° N) with a daily hot water demand of 500 litres at 70^oC, using flat plate solar collectors and an arduino microcontroller. The solar data used in this analysis were obtained from Photovoltaic Geographical Information System (PVGIS) and the method used is the active direct roof mounted solar water heating. The system design process consist of evaluating the optimum collector tilt angle, the thermal analysis of the flat plate collector and hot water storage tank and finally modelling a low cost automatic controller for the system using an Arduino in the Proteus software. The optimum annual average solar radiation on the tilted solar collector was obtained following the calculation of the conversion ratios of the direct_, diffuse and reflected radiations. At annual time scale, the appropriate tilt angle (β) that maximizes the collection of solar energy was 11^o and the corresponding optimum average irradiance of 432 W/m² wasobtained. The analytical results presented for the performance of the heater indicate that the system operates at an annual thermal efficiency of 55.49%. The control system simulation results indicate that the system uses 4.5kWh and 2.075kWh of energy to run the pump and the auxiliary heater respectively and produces 26.187kWh of energy to heat up the cold water from 25^oC to 70^oC for a single day.