Users Handbook for Solar Water Heaters
Introduction
Solar thermal technologies hold significant promise for India, with high solar insolation of to 4 6.5 kWh/ sq.m /day for an average of 280 sunny days. The solar water heating system is a commercially viable and technologically mature product which has existed in the country for many years. Yet, against a technical potential of 45 million sq. km. of collector area, approximately 6 million sq. km of collector area has been installed. This works out to a little more than 2 sq.m./1000 people as against countries like Israel and Cyprus, which have over 500 sq.m./1000 people.
In order to transform the solar water heating market in India, the Ministry of New and Renewable Energy (MNRE) has joined hands with UNDP/UNEP/GEF Global Solar Water Heating Market Transformation Strengthening Initiative. Under this project, India aims to achieve 20 million sq. m. collector area by 2022. In absence of any intervention, the market was projected to add much less million sq. m. during this period. International Copper Promotion Council (India) is also a partner to this project in India.
The climate of India varies from extremes to moderate, due to its large geographic size and varied topography. The climatic conditions in the northern hills are quite different than that of the southern parts of India, and in the plains also, extreme climatic conditions are common. The use of hot water is common for residential applications in the cooler regions of the country. In urban and semi-urban areas also, hot water use is becoming a part of the lifestyle. In all these areas, water is normally heated up with electricity, which is expensive and not available 24 x 7. Therefore, a solar water heating system can be the suitable alternative to meet the growing hot water requirement in the country, without exerting further demand pressure on the electricity generation capacity in the country. However, in quite a number of cases, solar water heaters had failed to earn appreciation of the users, due to sub-optimal design, inferior product quality, mismatch of technology with the environment and water quality and bad installation practices.