Working fluid selection and performance comparison of subcritical and supercritical organic Rankine cycle (ORC) for lowtemperature waste heat recovery

摘要

In the industrial and daily processes, a big amount of energy islost as waste heat. This heat source reduces not only the energyefficiency of industrial process but it also contributes to greenhousegases emissions and thermal pollution. In this context,the CERES project (Energy pathways for waste heat recovery inindustrial systems), financed by the French National ResearchAgency, aims at developing a decision-making tool to optimizewaste heat recovery in industrial process. Through this platform,the comparison of various technologies (heat pumps,thermoelectricity, ORC …) based on technico-economic basiswill be possible.In the article, it is proposed to describe one of these technologies,the Organic Rankine Cycles (subcritical and supercriticalcycle), which can be used to valorize low-temperaturewaste heat.The Organic Rankine Cycle performances were analyzedand compared via their thermal efficiencies and exergy analysis.Both of these cycles used a heat source simulated by hot airwith an inlet temperature of 170 °C and a heat sink that is waterat ambient temperature to cool down and condense the workingfluid. The performance calculations and the cycle simulationwere carried out by Engineering Equation Solver (EES).