Thermo-Economic Multiobjective Optimization of a LOW Temperature Organic Rankine Cycle for Energy Recovery

Abstract

In last decades the scarcity of combustible oil around the world has promoted the quest of new processes to produce power from alternative energy sources. The conventional Rankine cycle with water as working fluid, it is a good choice to convert heat into electricity but inefficient in temperatures below 350 C. Using an organic compound as working fluid the Rankine cycle (Called Organic Rankine Cycle) improves the cycle efficiency and can reduce the economy of the process for energy recovery from low temperature sources. In this work we proposed a set of organic compounds and a scenario of process to obtain simultaneously both optimum values of compositions of the mixture (used as working fluid) and operating conditions of the cycle for a given low temperature source. As design goals we set the minimization of total annual cost and the maximization of thermal efficiency. Because these two goals are in conflict the design problem was posed as a non-linear multi-objective optimization problem with thermodyn...