In view of the frequent fluctuation of temperature and flow rate of the available heat source in distributed energy system

the performance of the kW-scale organic Rankine cycle prototype with fluctuating heat source of 110～150 ℃ was tested and its multi-condition operation characteristics with the working fluid flow rate and expander rotary speed as the control variables was analyzed. The results showed that

the fluid mass flow rate was an effective control parameter to adjust the shaft power while maintaining the relatively stable system thermal efficiency. The shaft power was sensitive to the variation of heat source temperature while it exhibited different trends with the heat source mass flow rate. When the fluid mass flow rate was relatively small

there was enough redundancy in the heat transfer area. Under this condition

the heat source flow rate had quite weak effect on the ORC performance. With an increase in the fluid flow rate

the effect of heat source flow rate emerged. The ORC performance was deteriorated with the reducing heat source flow rate. The maximum shaft power and thermal efficiency of 4 kW and 6.0% could be achieved at the heat source temperature of 150 ℃.