Performance analysis of different working fluids for use in organic Rankine cycles

Abstract

This article presents a second-law analysis for the use of organic Rankine cycle (ORC) to convert waste energy to power from low-grade heat sources. The organic working fluids were selected to investigate the effect of the fluid boiling point temperature on the performance of ORCs. The working fluids under investigation are R134a, R113, R245ca, R245fa, R123, isobutane, and propane, with boiling points between 243 and 48 °C. The results are compared with those of water under similar conditions. A combined first- and second-law analysis is performed by varying some system operating parameters at various reference temperatures. Some of the results demonstrate that ORC using R113 shows the maximum efficiency among the evaluated organic fluids for temperatures >430 K; R123, R245ca, and R245fa show the best efficiencies for temperatures between 380 and 430 K; and for temperatures <380 K, isobutane shows the best efficiency. Also, it is shown that the organic-fluid boiling point has a strong influence on the system thermal efficiency.

Performance Estimation of Organic Rankine Cycle by Using Soft Computing Technics

“…Mago et al [24] presented organic refrigerant need not be superheated as the thermal efficiency ratio remains constant when the inlet temperature of turbine is increased. Furthermore, superheating organic refrigerants increase the irreversibility in the second law analysis.…”

The Exergy Loss Distribution and the Heat Transfer Capability in Subcritical Organic Rankine Cycle

“…That is, ξ < 0: a wet fluid, ξ~0: an isentropic fluid, and ξ > 0: a dry fluid. Isentropic fluid R245fa was selected as the working fluid based on its good cycle performance [9,10] and eco-friendly characteristics [35], and it has been widely used in ORCs up to now and is researched quite well [36]. However, the global warming potential (GWP) of working fluid is not considered in this research.…”

“…Also, many investigations on ORC are mainly focused on the choices of the working fluid [7][8][9][10][11][12] and its performance [13][14][15][16][17][18][19][20][21]. Hung et al [13] discussed the irreversible loss of the key parts in ORC and found that the maximum irreversible loss happens in the evaporator.…”

Modeling and control of Rankine based waste heat recovery systems for heavy duty trucks

“…Yet many challenges have to be faced before the vehicle integration. The first challenge deals with the correct choice of fluids and system architecture [Mago et al (2007), Grelet et al (2014)] and shows that system simulation is a critical part of the development work. The use of water-alcohol mixture can bring some advantages in the power recuperation and overcome both disadvantages of these fluids: high freezing temperature of water and flammability of alcohol [Latz et al (2012)].…”