Study of organic rankine cycle for power generation from engine waste heat recovery

The low and middle temperature Organic Rankine Cycle could be used to recover the low grade waste heat. The conditions of the engine exhaust gas vary in a range when the vehicle is running. It is difficult to confine the operation condition of ORC at a fixed point. In this paper the performances of different working fluids operating in a certain region instead of a single point were analyzed using a thermodynamic model built in Matlab together with REFPROP. The results of 9 different pure organic working fluids were compared in their regions when the net power output was the same value. The safety levels and their impacts to the environment were also evaluated. The results indicate that R11 and R141b manifest the best thermodynamic performances; however R236ea and R245ca are the most environment friend working fluids for the engine waste heat recovery application.