Thermal efficiency analysis of Organic Rankine Cycle (ORC) System from low-grade heat resources using various working fluids based on simulation

Thermal Efficiency of Organic Rankin Cycle (ORC) Power Plant System from low-grade heat resources using various working fluids has been analyzed based on the simulation. Four working fluids, namely R-134a, R-32, R-407A, and R-422C were selected on the simulated ORC system to determine its thermal efficiency in some temperature set up of evaporator and condenser. The working fluids are simulated with mass flow rate of 0.15 kg/s at evaporator exit temperature of 75°C, 80°C, and 85°C and at condenser exit temperature of 20°C to 50°C at each 5°C temperature difference. Fluid properties in these conditions are analyzed with REFPROP software then become data input for Cycle Tempo simulation. The thermal efficiency values of each temperature and refrigerant variation are then analyzed to obtain optimum value and variation for the simulated ORC system. The efficiency was obtained at the evaporator exit temperature of 75°C and condenser exit temperature of 45°C. ORC simulation revealed that the optimum and realistic working fluid was R-32 with thermal efficiency of 7.03 %.