Combined MGT – ORC solar – hybrid system. PART B : Component Analysis and Prime Mover Selection

This paper starts from the results of the paper “Combined MGT – ORC solar – hybrid system. Part A: plant optimization PART A” and, as far as the selection of the ORC expander is concerned, different solutions are compared between radial turbines, volumetric and scroll expanders. A preliminary extended similarity study aids the search of the most suitable expander to be adapted to the ORC application. Actually, the most critical aspects regard the change in the operating fluid with dramatically different characteristics in terms of compressibility effects, molecular weight, and transport properties. Once the adaptability of an existing expander to such a different fluid has been detected, the effectiveness of this choice is validated by a CFD analysis. The component analysis is completed by the investigation of the reacting flow through the MGT combustor supplied with natural gas or biogas.