Studies on combined cooling and drying of agro products using air cooled internal heat recovered vapour absorption system

摘要

The objective of this study is to develop an energy efficient heat pump combined storage and drying technology for agricultural products, to reduce the net energy consumption compared to conventional storage and drying systems. An experimental study of an improved air cooled condenser and absorber in ammonia-water vapour absorption refrigeration system and using more internal heat recovery by generator absorber heat exchangers is carried out simultaneously using the generated hot air for drying and better storage of the agricultural product. Vertical annulus radial grain bin dryer of 5 kg/h capacity is adopted to suit 10.5 kW for cold storage ammonia absorption refrigeration. The effect of heat sink and evaporator temperatures on the coefficient of performance (COP) of the system and the heat rejected from condenser and absorber for drying applications are studied. The temperature of the air at the outlet of the condenser/absorber is around 43-53 degrees C for various atmospheric conditions and is used for drying of the selected agro product (nylon sago) in the bin dryer. The drying characteristics of nylon sago, heat pump capacity and combined COP of the system are presented with descriptions. It is found that the combined COP of the system varies from 1.8 to 1.4 when the heat rejection temperature is between 53 degrees C and 43 degrees C respectively under actual operating conditions. (C) 2016 Elsevier Ltd. All rights reserved.