Thermal efficiency of open pan furnaces used in jaggery making is low. Lots of heat energy goes as waste through flue gases. Tapping part of this energy for other useful purposes would improve overall efficiency of the furnace. A waste heat recovery system (WHRS) has been developed for this purpose. It consists of a counter current type of heat exchanging system installed in flue gas channel of IISR furnace. Fresh air is sucked through it with the help of an electric blower and heated air is obtained at the outlet. A temperature rise of 30°C was obtained at mass flow rate of 160 kg/h with net energy gain of about 27 MJ in the span of 8 hours under steady-state conditions. This heated air can be used for bagasse drying, which is normally done under open sun and becomes difficult under overcast sky conditions. Jaggery drying and space heating may also be the area of usage of recovered heat.
