Trough Solar Thermal Power System-wide Thermal Performance Modeling And Simulation Analysis

With the rapid development of trough solar thermal commercial applications and its advantages and prospects in power generation,it is urgent to simulate its thermal performance and increase the efficiency of thermal collector.At present,most of the researches have been done on the experimental or simulation calculation of a single collector,and there is less research on the actual operation of a power plant for a series connection of multiple collectors.At the same time,the current research on convective heat transfer in tubes is mainly focused on the increase of internal fin structures of the heat collection tubes,such as circular and rectangular fins.However,there are few studies on the differences of different fins.Therefore,different fins in the heat collection tubes are not included.The structural enhancement of convective heat transfer needs further study.In this paper,a parabolic trough solar thermal power plant is established,and a complete operation model is established and a program is written for numerical calculation.Meanwhile,the effect of different fins on the convection heat transfer in the pipe is studied.The main work is as follows:Trough solar thermal power plant modeling.Two-dimensional heat balance modeling of trough collector was carried out,corresponding heat balance equation and heat transfer equation were established,and an iterative algorithm was established to solve outlet temperature of collector.According to the actual operation of the power plant,an iterative algorithm for the flow of heat transfer medium is established,and the temperature and mass change equations of the energy storage system during the operation of the power plant are established.Analyze the common operating conditions of trough solar power plants and establish a plant control flow with multiple operating conditions.The effects of solar radiation,inlet temperature of HTF,ambient temperature,ambient wind speed and flow rate of heat transfer medium on the working fluid temperature at the outlet of the collector were studied.Calculate the annual plant hourly operating parameters,including the quality of the circulating pump flow,collector heat output,steam turbine heat input,power generation,etc.,analysis of the annual operating conditions,and compared with the results of the SAM software to analyze the error.By changing the design parameters of the power plant,such as installed capacity,collector type,collector type and heat storage time,the annual power generation of power plant with different design parameters is calculated and the calculation results are analyzed.Calculating the annual electricity generation in 40 regions of the country,saving the standard coal amount,reducing the carbon emission and comparing with the distribution of the national solar energy resources,providing a reference for the site selection of power plants.Aiming at the non-uniform heat flow characteristics of trough collector tube,the effects of rectangular,triangular and cylindrical fins on the convective heat transfer in the collector tube were studied based on the enhanced convective heat transfer in the tube.The numerical simulation was carried out by COMSOL software.The effects of Reynolds number,inlet temperature and incident energy on tube flow and heat transfer were analyzed.And economic evaluation coefficient EEC is defined,and different fins are discussed based on this coefficient.The results of this paper have certain reference value for the operation and management of trough solar power plant,and have important theoretical significance and application space for strengthening the convection heat transfer and increasing the efficiency of the heat pipe.