Experimental performance of a piston expander in a smallscale organic Rankine cycle

Volumetric expanders are suitable for more and more applications in the field of
micro- and small-scale power system as waster heat recovery or solar energy. This paper
present an experimental study carried out on a swatch-plate piston expander. The expander was
integrated into an ORC test-bench using R245fa. The performances are evaluated in term of
isentropic efficiency and filling factor. The maximum efficiency and power reached are
respectively 53% and 2 kW. Inside cylinder pressure measurements allow to compute
mechanical efficiency and drown P-V diagram. A semi-empirical simulation model is then
proposed, calibrated and used to analyse the different sources of losses.