Working fluid selection of organic Rankine cycle with considering the technical, economic and energy analysis

Abstract

The technology known as organic rankine cycle (ORC) is a dependable method for transforming heat into electricity, whether it is for use in renewable energy sources such as biomass, geothermal, and solar, or for improving industrial energy efficiency. The range of ORC systems spans from small-scale (a few kW) for home cogeneration to sizable multi-megawatt geothermal power facilities. Since the 1970s, technology has undergone significant progress, largely due to increased economic incentives and rising energy costs, despite a slow start initially. Tracking the evolution of the technology worldwide is challenging due to the wide variety of applications, manufacturers, and countries involved. Hence, the present research scrutinizes the ORC technology to evaluate this system from the energy and economic perspectives. Aspen HYSYS, and Aspen Capital Cost Estimator simulations were used for the process, thermodynamic, and financial evaluations, respectively. In this research, the ORC is evaluated using various organic working fluids, specifically seven different types of fluids. The power and heat flow of the expander in all scenarios are considered at 1200 kW and 1.200 Mw, respectively, to determine the most appropriate organic fluid. Organic fluid toluene, due to its highest boiling point among the investigated fluids, was able to generate the required production power using the lowest molar flow rate for both input and output to the expander, considering these values. The results showed that the organic fluid toluene is technically and economically superior to other fluids. However, cyclopentane performs slightly better in terms of energy consumption and carbon dioxide output. However, toluene is chosen over cyclopentane due to current safety concerns.