Performance evaluation of a micro turbo-expander for application in low-temperature solar electricity generation

A micro turbo-expander capable of high working speed was specially manufactured for use in an organic Rankine cycle (ORC). A series of tests were executed to examine the performance of the machine. In the experiment, the machine was tested under different inlet pressure conditions (0.2–0.5 MPa). Data such as the compressed air pressure, temperatures of the inlet and the outlet, rotational speed, and electric power generation were analyzed to discover underlying relationships. During the test, the rotational speed of the machine reached as high as 54 000 r/min, the peak value of the temperature drop between the inlet and the outlet reached 42 °C, the maximum electric power generated by the motor-generator attached to the machine reached 630 W, and the efficiency of the machine reached 0.43.