A Microcontroller-Based Active Solar Water Heating System for Domestic Applications

A potential solution to adequate and sustainable electricity supply problems in most developing countries is dependent on proper harnessing of solar (radiant) energy. Owing to the over dependence on fossil-fuel based energy, there is an exponential rise in carbon dioxide (CO2) emissions into the atmosphere, thereby causing severe environmental degradation and ozone layer depletion. This paper seeks to apply the readily available radiant energy source to solar water heating, and establish possible economic benefits to its use in domestic applications for residents of Covenant University campus. The microcontroller-based active solar water heating system (ASWHS) is designed to effectively absorb radiant energy using solar collectors, and store it as hot water in a water tank via a direct current (DC) circulation pump powered by a stand-alone photovoltaic (PV) system. The design also incorporates an auxiliary electric heater which is put to use only when there is insufficient radiant energy. A case study is reported to show the importance of the ASWHS for domestic water heating. The maximum design efficiency and the expected energy output of the solar collector throughout its working life is 79.94% and 498,225kWh respectively. A reduced dependence on grid supply and/or fossil-fuel based generator sets during hot water demand periods is recorded using the ASWHS with a high payback period of 15 years; and a lower unit cost (US$0.01/kWh) of the ASWHS makes it more economically viable as compared to the unit cost (US$0.18/kWh) of the grid supply for the same amount of energy consumed.