Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.
Efficient, cost effective and light weight solar collectors to meet the low temperature needs, at or below 100oC will be the better option for utilisation of solar energy in developing countries like India. Test results of a patented low cost light weight modular solar collector developed and tested at Heat Pump Laboratory at IIT Bombay, HPL_IITB, (1907 N 7251 E) are presented. A 5 m2 aperture collector was installed on HPL_IITB terrace with an optimum tilt of 47o for the month of December. Heat delivered by the collector in terms of ambient air heated to 70.3oC, at average mass flow rate of 53.9 g/s, over 9 h test period was 21.5 kWh with an efficiency of 70.2%. Power consumed by air circulating fan was less than 1% of the heat delivered by the collector. Weight of this novel collector is only 7.6 kg/m2. Collector costs approximately INR 5,000/m2 (USD 82/m2) which works out to be about INR 1,200/kWh.d-1 (USD 20/kWh.d-1). Payback calculated, without any subsidy, when used for industrial heating applications is approximately 252 days.