Effect Of Climatic Conditions On Performance Of ORC Using Environment-Friendly Working Fluids – Special Reference To India

Abstract

<p>Efficient heat recovery from low-grade heat sources is an achievable scientific frontier in the coming decade. One of the promising technologies in waste heat recovery is the organic Rankine cycle (ORC) system. Major obstacles to low-grade heat recovery include economic viability, scale, system efficiency, and exergy efficiency. In low temperature ORC systems, the cost of condenser becomes significant and hence air-cooled condenser is a feasible option. However, the performance of the air-cooled condenser is sensitive to the variation in ambient air conditions. India, being a tropical country, have villages and cities whose average temperature varies from -2oC in winter to 50oC in summer. The present work involves the study of heat transfer effects on the condenser using common organic working fluids and quantifying the consequences of environmental temperature variations. The constant thermal evaporator load is supplied with a medium-enthalpy heat source at 100 and 150oC. The atmospheric temperature associated with heat rejection from the condenser is varied from 273K to 313K for 5 working fluids. A MATLAB model of the ORC system is developed to study the effect of condenser performance on the first and second law efficiency of the ORC system. The MATLAB model is used to investigate the effect of varying inlet temperatures of the working fluid on the performance of ORC system to choose an organic working fluid suitable for Indian climatic conditions. R365 mfc, and R1233zd exhibit higher expander work and show higher heat rejection. At higher heat source temperatures of 150oC, the simulation shows a higher second law efficiency for the working fluid R1224yd(Z), which has critical temperature closed to the heat source temperature.</p>