Electrical and energy study of a volumetric microexpander in an ORC micro power plant

This paper presents the results of an electrovibrational investigation of the expansion unit in a micro-CHP ORC power plant. The study demonstrates that a maximum electrical output of approximately 0.64 kW was achieved in the ORC system at an HFE-7100 flow rate of 0.06 kg/s and a heat source power of 16 kW. It has been determined that, for any given working fluid flow rate, there is an optimal heat source thermal power at which the electrical output of the ORC system reaches its maximum. In contrast, for any preset heat source power and working fluid flow rate, there is an optimal generator load at which the electrical power output of the ORC system is maximised. It has been observed that, irrespective of the working fluid flow rate, changes in thermal power cause the electrical power output of the ORC system to vary along the generator’s load line. The research also included vibration measurements, which showed that the operating conditions of the expander unit, including the electrical load on the generator, influenced the vibroacoustic behaviour of the machine.