Simulation Of Thermochemical Thermal Storage Reactor Based On Solar Energy

Large-scale thermal energy storage(TES)is a key link for the reliable and economical operation of concentrated solar power plant(CSP).The current development trend of heat storage technology research and development is:the development of high-efficiency and low-cost heat storage systems is the direction of clean heat supply in the future;higher heat storage temperature range and greater heat storage density;operation technology meets the reliability of large-scale production.Among the heat storage methods,thermochemical heat storage(TCS)has high heat storage density and heat storage temperature,and no loss occurs during heat storage.It can store heat across seasons,reduce heat storage costs,and improve energy efficiency.The advantages of this have aroused the attention of researchers.However,thermochemistry has the problems of complex process and low technological maturity.To make the reaction process and the flow and heat transfer performance of the heat exchange medium match well,further research is needed.Based on a series of researches carried out at the level of reaction materials and reactor design,this article focuses on the feasibility of applying thermochemical heat storage systems to power generation,and studies the fixed reactors with coated porous media carriers.With the goal of developing a low-cost,high-efficiency,and stable-running reactor,the reaction design adopted in this paper uses CSP as the heat source and high-temperature air as the heat transfer fluid and reactant,based on the Brayton cycle power generation technology;the core of the reaction is mainly composed of The screened reaction material-metal oxide Co3O4 is used as a coating and is coated on the porous medium matrix.The paper adopts numerical simulation method,and calculates and analyzes related parameters.The following work is carried out around the reactor:(1)The permeability of the honeycomb ceramic follows the Darcy-Forscheimer model.In order to determine the resistance characteristics and heat transfer of the porous medium,a three-dimensional model is established for the single channel of the honeycomb ceramic,and the mathematical model of the permeability of the porous material is predicted by this;(2)Using the surface chemical reaction model and the porous media model,a two-dimensional axisymmetric reactor model is established and calculated in Fluent,which is verified with the experimental results of no chemical reaction and chemical reaction and the calculation results of the model respectively.(3)The effects of stable and non-stable heat sources,the porosity and aspect ratio of the reaction core,and the effect of heat storage efficiency are studied.The operating conditions and structural parameters of the heat storage system are optimized.(4)The paper calculates the convective heat transfer,radiation and effective thermal conductivity of the porous medium model of the ceramic foam.The performance of the honeycomb ceramic and the foam ceramic are studied respectively.The convective flow and the effective thermal conductivity of the two types of reactor carriers are compared and studied.Heat transfer characteristics and chemical reaction laws,according to its characteristics,a composite reaction structure is designed and the composite ratio and porosity of honeycomb and foam are discussed,so as to reduce the resistance loss,enhance the heat transfer of the reactor and improve the overall efficiency.