Thermo-economic evaluation of low global warming potential alternatives to HFC-245fa in Organic Rankine Cycles

Abstract In the present work, a thermo-economic evaluation of the low global warming potential fluids HCFO-1233zd-E, HFO-1336mzz-Z and HFO-1234ze-Z as alternatives to HFC-245fa in organic Rankine cycle systems for low temperature heat sources is carried out. A thermodynamic organic Rankine cycle model is extended with the overall cost of the system, and it is used to identify the system parameter values for each working fluid considered that minimize the specific investment cost at a given set of the heat source and sink inlet temperatures. Thereby, the results show that HCFO-1233zd-E and HFO-1336mzz-Z present higher efficiencies than HFC-245fa, while HFO-1234ze-Z presents lower efficiency than HFC-245fa. The low global warming potential working fluids result in lower specific investment cost values than HFC-245fa. HFO-1336mzz-Z presents the lowest specific investment cost and highest efficiency values among the working fluids of interest throughout the range of operating conditions studied.