New classification of dry and isentropic working fluids and a method used to determine their optimal or worst condensation temperature used in Organic Rankine Cycle

Abstract

The organic Rankine cycle (ORC) is a popular technology for utilization of medium-low grade thermal energy. The thermophysical properties of working fluids can greatly affect the economic performance of ORC system that is an important factor affecting its application and development. Heat exchangers account for the largest proportion of investment in the whole ORC system. In this paper, a curved triangle is defined to describe the condensation characteristics of dry and isentropic working fluids. Using this model, a new classification of dry and isentropic working fluids and their application characteristics in ORC are proposed. Moreover, a method used to determine the theoretical optimal or the theoretical worst condensation temperature of dry and isentropic working fluids is proposed. The work in this paper may offer a good help for the determination of practical condensation temperature of ORC system and its design and establishment.