Effect of resistive load on the performance of an organic Rankine cycle with a scroll expander

Abstract

A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. AbstractAn experimental investigation is performed for an organic Rankine cycle system with different electrical resistive loads. The test rig is set up with a small scroll expander-generator unit, a boiler and a magnetically coupled pump. R134a is used as the working fluid in the system. The experimental results reveal that the resistive load coupled to the scroll expandergenerator unit affects the expander performance and power output characteristics. It is found that an optimum pressure ratio exists for the maximum power output. The optimal pressure ratio of the expander decreases markedly as the resistive load gets higher. The optimum pressure ratio of the scroll expander is 3.6 at a rotation speed of 3450 r/min for a resistive load of 18.6 Ω. The maximum electrical power output is 564.5W and corresponding isentropic and volumetric efficiencies are 78% and 83% respectively.

Improving the semi-empirical modelling of a single-screw expander for small organic Rankine cycles

“…The shaft power output, which is a more representative result than the electric power output in terms of mechanical characterization of the expender, increases with (i) the fluid pressure at the expan-der inlet, (ii) the rotational speed and (iii) the pressure ratio. Sim-ilar trends were achieved by other researchers [10,45,48,49] in their characterization of scroll expanders. Thus, such a behavior is common for positive-displacement expanders.…”