Thermodynamical and Economical Valuation of low-temperature ORC with Alternative Working Fluids

Abstract

In order to use the comparatively low German thermal water temperatures of 120 to 160°C effectively by deep geothermal power stations, The Organic-Rankine-Cycle (ORC) is deployed. Due to the substantial global warming potential of the working fluids currently in use and the lawfully compulsion of their replacement in the near future, alternative workingfluids to operate power plants using the ORC-process need to be found. For that purpose, this thesis evaluates a selection of organic fluids with a power plant simulation. The most productive candidates are compared with conventional working fluids with regard to power output, cost and material compability. Furthermore, necessary technical and economical effort in terms of the substitution of the fluids is examined.