Development of Direct Heating Solar-Electric Hybrid Hot Water System for Domestic Usage

Abstract

The energy generation and consumption in both, industrial and domestic level, is rapidly increasing in the world. Moving away from the existing reliance on fossil fuels and towards a more secure, clean and sustainable energy portfolio is a popular trend in the industries. Solar-based energy systems can be used to deliver not only electricity, but also hot water, space heating and even cooling, depending on the requirements. This study focused on the domestic hot water supply system with a new improvement of electric hybrid system. The objective of this study was to develop a solar-electric hybrid hot water system that can supply hot water at a constant temperature. In this study, a solar collector was used to collect the solar energy to heat up the water. Two kinds of experiments were conducted: Direct heating, where hot water coming out from the solar collector is directly sent to a storage tank and Indirect heating, where heat exchanger is used to exchnage the heat from hot water coming out from the solar collector to a storage tank water. Experimental results show that direct heating is suitable for water heating using solar energy, since it showed higher temperature increment from 8.30 am to 11.30 am with a temperature increment rate of 43% compared to the indirect heating. Wide variety of Solar-Electric hybrid hot water systems are available in the world for industrial usage as well as domestic usage. This kind of systems are mostly used for indusrial purposes in Sri Lanka. Solar hot water systems and electric hot water systems are widely used for domestic purposes. However, the domestic usage of Solar-Electric hybrid hot water systems are minimum in Sri Lanka. The aim of this study is to develop a Solar-Electric hybrid hot water system, which is domestic level usage suitable for Sri Lanka.