Experimental Investigation on the Characteristics of ORC System with Twin Screw Expander

doi:10.3901/JME.2017.24.177

Abstract

Abstract: The organic Rankine cycle (ORC) is a promoting energy saving technology which recycles the heat of low temperature and converts it to mechanical power. The expander as a key component has great influence on the system's efficiency. Among different types of expander, twin-screw expanders draw much attention due to its advantages of high reliability, strong adaptability and less parts. An ORC system with twin screw expander is designed and a corresponding test rig is developed choosing R245fa as its working fluid. Then, an experimental study of the ORC system is carried out to analyze the influence of the expander speed, working medium pump frequency and the superheat degree of the vapor into the expander. The results show that the mass flow rate of working fluid increases with the increase of expander rotational speed, but the evaporating pressure is less affected by the expander speed. The system efficiency exists an optimal value when the expander speed matches well with the pump frequency. The mass flow rate of working fluid and the evaporating pressure increase with the increase of working medium pump frequency. As a result, the expander output power and system efficiency will also increase. The superheat degree of working fluid has little effect on the system efficiency.

Key words: characteristics investigation, organic Rankine cycle, twin screw expander

CLC Number:

TK11

GUO Ting, SHEN Jiubing, KONG Xianglei, ZHANG Zhen. Experimental Investigation on the Characteristics of ORC System with Twin Screw Expander[J]. Journal of Mechanical Engineering, 2017, 53(24): 177-183.

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