Research Of Working Fluids Of Engine Exhaust Gas Waste Heat Recovery Based On Organic Rankine Cycle (ORC)

When the Internal Combustion Engine is running, the exhaust gas take away about 35% of the oil heat. But now this part of heat is only scattered as waste heat, so how to reuse this part of waste heat effectively becomes a very important issue. The Organic Rankine Cycle (ORC) is a kind of Rankine Cycle that using organic working fluid instead of water. The cycle which is widely used has a very simple structure and obvious advantages of downsizing, so it is very suitable for low temperature waste heat recovery. Because it produces extra power output without any pollutant, Organic Rankine cycle (ORC) as a way of recovering the low-grade heat energy is drawing more and more attention.The working fluids selection is an important research topic when using ORC recovery mode. In this paper we summarized the commonly used organic fluids and established the working fluid database. We also established mathematical model to derive the thermo-physical properties of uncommonly used working fluid and then verified the accuracy by comparing the results with NIST-Refprop 8.0.The research of ORC using siloxane as working fluid is difficult for the lack of basic thermal properties. This paper derived the Contribution-coefficient to specific heat of Silicon-group by the group contribution method. This provided a guarantee for the analysis of ORC using sioxane as working fulid.The working fluid is divided into three categories: commonly used fluid, siloxane and zeotropic fluid. All kinds of fluid are analysed and compared in the mathematical model based on EES and Aspen plus. A procedure summarized to select the working fluid for the Organic Rankine cycle which is used for recovery the waste heat of ICE .This provides a set of principle and method for the future work of heat recovery.