Design and performance evaluation of solar - LPG hybrid dryer for drying of shrimps

Abstract

The study was aimed at design and development of an energy efficient solar dryer suitable for continuous drying operation. In this dryer, water was used as a thermal energy storage and heat transfer medium, and air as an intermediate fluid. The major parts of the dryer were flat-plate solar water collector, water storage tank, drying chamber, heat exchanger, and liquefied petroleum gas (LPG) water heater. The dryer was designed to work mostly on solar energy during peak sunshine hours and LPG water heater as auxiliary heat source during low sunshine hours. The performance of the developed solar-LPG hybrid dryer was evaluated using shrimps. The moisture content of fresh shrimp was reduced from 76.71 per cent to 15.38 per cent within 6 h of drying. The drying rate curve showed that shrimp drying occurred under falling-rate drying period. Results revealed that the water was capable of capturing maximum heat energy during peak sunshine hours. The maximum collector outlet temperature of 73.5 degree celsius was obtained during drying. Overall, solar system supplied 73.93 per cent of heat energy and LPG water heater assisted rest of the energy requirement due to lower incident solar radiation during start and end of drying. The maximum collector and drying efficiency obtained for shrimp drying were 42.37 per cent and 37.09 per cent, respectively.