Cost-effectiveness performance analysis of organic Rankine cycle for low grade heat utilization coupling with operation condition

• A net power output model is proposed and compared with theoretical data.
• For fixed operation condition, low Ja fluid shows attractive performance in ORC.
• The heat source rather than working fluid determines ORC performance at low Ths,in
• The peak Wnet and best CEP cannot be achieved at the same time, compromise must be made.

This paper analyzed the influence of working fluids selection and operation conditions on the cost-effectiveness performance and net power output of an ORC for low grade heat utilization. A net power output model has been proposed theoretically and compared with the theoretical data calculated from thermodynamic analysis, exhibiting excellent agreements with the theoretical data. The proposed net power output model theoretically indicates that Jacob number and the ratio of evaporating temperature and heat rejected temperature play essential roles in discriminating the net power output among various working fluids at the same operation condition. For a given condensing and evaporating temperature, it can be concluded theoretically that fluid with low Jacob number will show attractive performance in an ORC. The maximum net power output is determined by the heat source rather than working fluids with a low inlet temperature of heat source. Cost-effectiveness performance analysis reveals that the maximum net power output and the best CEP cannot be achieved at the same time and compromise must be made when choosing the most suitable organic working fluids in different ORC designs.