Research On Optimal Design Of Electric Heating Solid Energy Storage Heating System

Coal-fired heating is mainly used for heating in northern winter.Due to the shortage of energy,the situation of environmental pollution is increasing,the consumption of fossil energy is huge,and the difference between the peak and valley of power supply is increasing year by year.It is one of the important ways to achieve clean heating to effectively control and alleviate the smog in the northern region due to the environmental pollution caused by traditional coal burning.At the same time,under the dual carbon goal,the use of solid-state electric heat storage technology can effectively reduce the abandonment of renewable energy and reduce carbon emissions,which will help China to achieve the goal of "carbon neutralization" as soon as possible.However,the temperature distribution of the solid electric heat storage device is uneven during the operation,and the heat accumulation causes the heating wire to burn out,which restricts the long-term,safe and stable operation of the solid electric heat storage system.Moreover,the initial investment of the solid electric heat storage device is relatively high,which affects the popularization and use of solid electric heat storage devices.In this thesis,ANSYS Fluent simulation software is used to study the structure of the heat storage device.By optimizing the structure of the heat storage device,the temperature distribution inside the heat storage body is improved,thereby reducing the adverse effect of heat accumulation on the heat storage body.The objective function is to establish the economic optimization model of the solid electric heat storage system,reasonably match the heat storage capacity of the solid electric heat storage device,and reduce the initial investment of the system,thereby providing theoretical guidance for the promotion and application of the system in the Beijing-Tianjin-Hebei region.This thesis has carried out the following aspects of work:Firstly,the research status of solid heat storage materials,heat storage structure and heat storage / release performance,application of typical heat storage devices and economic analysis at home and abroad are summarized.On this basis,combined with the working principle and composition of a typical solid electric heat storage system,the problems existing in the practical application of the system are analyzed.Secondly,for the typical heat storage brick structure,physical models of heat storage units with different ventilation duct structures are established to analyze and compare the influence of parameters such as the duct structure of heat storage bricks and inlet air velocity on the heat storage/heat release performance of the heat storage unit,and simulate the calculation results.It is shown that the heat storage brick with the rectangular channel aspect ratio of 18:1 has the best heat storage/release performance.Then,taking the heat storage module composed of the optimized heat storage unit as the research object,the cross-section temperature field and temperature uniformity of the heat storage module were simulated and analyzed by the brick arrangement(cross-arrangement and parallel arrangement)of the heat storage module.The influence of the series/parallel mode of the heat storage module on the temperature field of the cross section of the heat storage body and the heat storage ratio.The results show that the heat transfer performance of the heat storage module with the heat storage bricks arranged in a row is better,which is beneficial to the uniform heat storage/release.The heat storage body adopts the parallel mode of heat storage modules,and the approach degree of the actual heat storage and the theoretical heat storage and the uniformity of the temperature distribution are higher than those of the series connection of the heat storage modules.The approximation degree of the actual heat storage and the theoretical heat storage and the uniformity of temperature distribution in the parallel mode of thermal storage modules are higher than those in the series mode of thermal storage modules.Finally,taking the solid electric heat storage system of a hotel in Zhangjiakou as the research object,using De ST software to calculate the hourly heat load of the building,on this basis,the economic analysis of the solid electric heat storage system is carried out.The objective function is optimized to reasonably match the heat storage capacity of the solid electric heat storage device.At the same time,the influence of the peak-to-valley electricity price ratio of the heat storage capacity on the economy of the system is also analyzed.