Entropy Generation Analysis of A Low-Temperature Waste Heat Power Generation System Integrated with the Agricultural Machinery

Abstract

The heavy-duty diesel engines play a significant role in agricultural production. However, the lower efficiency, higher fuel consumption, and environmental pollution put a barrier to their effective utilization in the farmland. Hence, there is an urgent need to effectively enhance efficiency by tapping the rejected heat, which is otherwise directly expelled into the atmosphere. The present work proposes an entropy generation analysis of the heat recovery system. The conventional energy analysis is not sufficient to detect the sources/components for maximum exergy destruction. Hence, entropy generation analysis based on the second law is implemented to obtain the exergetic efficiency. The organic Rankine cycle using R-245fa as working fluid is used to recover the rejected heat discharged from coolant, lubricating oil and intercooler. The total exergy input to ORC system is calculated as 545 kW. The maximum irreversibilities are found in the evaporator (137kW) which is approximately 25% of the total exergy input followed by turbine, condenser and pump. The total exergy loss is higher in condenser as compared to turbine whereas irreversibilities are more in turbine than condenser. It means that a huge available work is lost in the cooling water.