Study of a roots expander in an organic Rankine cycle: semi-empirical model

Abstract

Several themes can be tackled in the thematic of organic Rankine cycles. Global system can be optimized as well as each cycle component. In the framework of this master thesis, a key part of an ORC is deeply analyzed: the expander. Indeed, this component is the one directly providing the mechanical power that can be converted in electricity. Many factors can influence its performances which gives to the study a certain complexity. Several expansion machines exist and the one studied here is a roots expander. Developed first to be a compressor, it is not common to see it used as an expander, which made this work original and stimulating. The roots is a volumetric machine outstanding because of an internal volumetric ratio close to 1. The idea is to develop a semi-empirical model based on an experimental campaign, followed by a serious analysis in term of performances.