In order to study the output performance law of scroll expander

a commercial scroll compressor was modified to a scroll expander

and its lubrication system was designed and accurately controlled. On this basis

a test bench with compressed air as working fluid was built up

the performance of the expander with or without lubrication was compared and the performance of the expander was tested. The result shows that

the lubrication system has good effect on mechanical lubrication and expander performance. Firstly

the isentropic efficiency of the expander kept above 40% under the whole range of experimental conditions

the maximum isentropic efficiency of 54.45% was achieved

and the maximum output electric power of 753 W was achieved. Secondly

the output power of the expander increases with the air flow

but the isentropic efficiency decreases with the increase of air flow. Thirdly

the isentropic efficiency of the expander increases at first and then decreases with the increase of the speed of the expander

and the optimal isentropic efficiency speed range of present expander is 2 800～3 200 r/min. Fourthly

when the speed is fixed

the output power of the expander depends on the inlet pressure. With the increase of the load

the output power of the expander and the inlet pressure have a similar growth trend. The study can provide guidance for optimization of the ORC system.