Performance Analysis And Matching Research Of Expander Based On Solas Multi-Coupling System

The solar multi-coupling system is a system for multiple energy supply of cold,heat and electricity.The Rankine cycle system as a key subsystem not only needs to be well matched with the heat collecting system to realize efficient conversion of heat energy,but also needs to be well matched with the heating system to achieve efficient delivery of thermal energy.The expander plays a vital role in the Rankine cycle.The great performance about the expander is the guarantee of safe and efficient operation of the system.It is also important to select the appropriate expander to achieve the energy level matching according to the actual condition.This paper firstly compares and analyzes several ways of solar thermal utilization,then three different schemes of solar multi-coupling system are proposed:the two-stage driving system,the indirect driving system by condenser system and the direct driving system by the expander exhaust steam.Based on the analysis the thermodynamic property and economy,it is concluded that the direct driving system by the expander exhaust steam reduces the heat loss and the system cost.This paper proposes a new type of solar multi-connection system by combining the two-stage driving system and the direct driving system.The expander is proposed as an important thermal power conversion device,which affect performance of the solar multi-coupling system,and is mainly analyzed in the following chapters.Then,the screw expander and radial turbine are studied,and the working principles of the two expanders are explained respectively.The models of the screw expander and the radial turbine are constructed,and the value of the performance evaluation index are iteratively calculated.It can be found that the performance of the different expanders is different,especially in the different inlet pressure,inlet temperature,exhaust back pressure and speed.In comparison,operating conditions have little effect on the performance of the screw expander,while the inlet pressure and the exhaust back pressure have a greater influence on the radial turbine performance.Finally,based on the empirical range of several key influencing factors,this paper obtains the optimum operating range and power range of the two expander and the preferred principles of the expander under different occasions.In practical applications of the expander,the boundary conditions of the application should be analyzed first,and the initial selection should be made according to the suitable working condition range and power range,and then compared and analyzed according to preferred principles to determine the most suitable expander.