Thermoeconomic Optimization of Organic Rankine Cycle (ORC) for Low Grade Heat Recovery at Temperatures below 100℃

Abstract

Low-grade heat sources are abundant on earth but are majorly untapped due to lower thermodynamic efficiency at low temperatures and cost considerations. A cost-effective technology is needed to convert this energy resource into useful forms of energy. This work aims at optimizing Organic Rankine Cycle (ORC) based heat engine and a cogeneration system developed to produce electricity and refrigeration from a heat source below 100℃, from both thermodynamic and economic point of view. Exergoeconomics, an algebraic thermoeconomic method, was used to analyze and optimize the systems for cost-effectiveness and exergetic efficiency. Also, the prototype of the cogeneration system was experimentally tested. The results exergoeconomic optimization show that the cost-effectiveness of the cogeneration system can be significantly improved by design parameter changes. The experimental results obtained were comparable with the results obtained from theoretical simulations.