Energetica India nº91 July August 2020

CASE STUDY 56 energetica INDIA- July-Aug_2020 itative produce that would also make commercial sense. It entrusted the task to National Institute of Solar Energy (NISE) to develop a prototype solar thermal air dryer, which came up with a vacuum tube collector drying system. The solar collector is a 5.2 m2 aperture area vacuum tube collector. It is joined with a 1m3 drying chamber that can hold 100 kilograms of raw apricots. Phase change material form of storage is used to ensure round the clock drying during dark hours. The solar drying units can be easily modified during installation to provide room heating in the winter thus saving on purchase of firewood. Each unit costs about INR 250,000 and the payback period is three years. Presently 600 drying units are already commissioned and by the end of year additional 400 units are expected to be oper- ational. They will, combined, save up to 600,000 kilograms of fuelwood and abating 1,000 tons of CO 2 annually. Source- Solar Thermal Federation of India