Abstract

Taking net power output as the optimization objective, the exergy loss distribution of the subcritical Organic Rankine Cycle (ORC) system by using R245fa as the working fluid was calculated under the optimal conditions. The influences of heat source temperature, the evaporator pinch point temperature difference, the expander isentropic efficiency and the cooling water temperature rise on the exergy loss distribution of subcritical ORC system are comprehensively discussed. It is found that there exists a critical value of expander isentropic efficiency and cooling water temperature rise, respectively, under certain conditions. The magnitude of critical value will affect the relative distribution of exergy loss in the expander, the evaporator and the condenser. The research results will help to better understand the characteristics of the exergy loss distribution in an ORC system.

Highlights

  • With the fast growth of fossil fuel consumption, the use of low grade waste heat has attracted public attention in recent years

  • Organic Rankine Cycle (ORC) with a low temperature source, it is necessary to temperature heat source,distribution it is necessary study irreversibility distribution the heat transfer study the irreversibility andtothe heatthe transfer capability of the ORCand system under some capabilityconditions, of the ORCsuch system under some different conditions, such as the of pinch heat source different as the variation of heat source temperature, the variation evaporator point temperature, difference, the evaporator pinch point temperature difference, the expander isentropic efficiency, temperature the expander isentropic efficiency, the cooling water temperature rise and theon

  • This paper discussed the influence of heat source temperature, the evaporator pinch point temperature difference, the expander isentropic efficiency and the cooling water temperature rise on the exergy loss distribution and the heat transfer capability of the subcritical ORC system by using

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Summary

Introduction

With the fast growth of fossil fuel consumption, the use of low grade waste heat has attracted public attention in recent years. Organic Rankine Cycle (ORC) is one of the attractive methods to recover low-grade waste heat. ORC with a low temperature source, it is necessary to temperature heat source,distribution it is necessary study irreversibility distribution the heat transfer study the irreversibility andtothe heatthe transfer capability of the ORCand system under some capabilityconditions, of the ORCsuch system under some different conditions, such as the of pinch heat source different as the variation of heat source temperature, the variation evaporator point temperature, difference, the evaporator pinch point temperature difference, the expander isentropic efficiency, temperature the expander isentropic efficiency, the cooling water temperature rise and theon. When the theexpander expander isentropic efficiency is fixed at avalue, highthe value, the exergy loss in the. When isentropic efficiency is fixed at a high exergy loss in the expander is expander is very low. This research will of exhibit the predicted results inexhibit detail. the predicted results in detail

System Description and Assumptions
Mathematical Model
Results and Analysis
TheThe
K totemperature
The Exergy Loss Distribution of ORC System
The Heat Transfer Capability of ORC System
The Exergy Loss Distribution
Conclusions
Full Text
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