System modelling for Rankine Cycle waste heat recovery from a spark ignition engine

Abstract

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.The Rankine Cycle can be used to convert low grade heat, including the dual heat sources of a spark ignition engine, into useful energy. To maximise the shaft power output, by optimising the capture of waste heat, requires detailed consideration of the cycle thermodynamics. A spreadsheet model for each proposed Rankine Cycle configuration has been developed and the results verified by comparison with a standard industry process engineering software package. The spreadsheet model results may be more reliable because the thermodynamic data are based on real data rather than equations of state. Comparisons of the proposed cycles are given for hexane as the working fluid.