Development of twin piston expander with solenoid valve for organic rankine cycle

This paper presents the progress of development of a new twin-type piston expander, (TPE) to be used as an expansion unit for a low temperature organic Rankine cycle (ORC). The lack of suitably suitable available expanders and most of the available expander are commonly limited to a certain range of operation. As an initiative to introduce a suitable expander, and the available type of expanders operation commonly limited for a certain range of operation. Therefore, in this study, an existing unused twin piston compressor has been converted into a TPE, with a few modifications on the compressor on by replacing the compressor valves with a solenoid valve and its ports conditions. The newly developed TPE behavior, functionality and performance are were tested at different inlet temperature and pressure. The preliminary results observed showed that the power produced by the TPE is was proportionally changed to the inlet temperature and pressure, and it is was recorded that the highest power of 3.4 kW achieved when TPE operated at 7 bars with 153 °C inlet temperature. Meanwhile, it was also observed that the rotational speed variation depends on the inlet pressure stronger than it does on the inlet temperature. The results also revealed that the TPE is feasible to be used as an expander for the ORC system with several improvements before it is adapted into the system.