Experimental Study On Heat Storage And Heat Transfer Characteristics Of Phase Change Microcapsule Fluids

The central heating area in the north has been increasing year by year.The combined heat and power unit has the advantages of high thermal efficiency and low environmental pollution.Therefore,it has become the mainstay of the central heating system.About one-third of the total urban heating area is provided by the CHP Production unit for heating.Cogeneration is the output of electricity as a by-product of heating while meeting the heating system's operation.However,such a mode of heat and electricity will result in excess electricity generation at the time of electric load trough or insufficient electricity generation at the peak of electric load,So there is a new idea,that is,adding heat storage device in the system.That is,when the unit heat output is higher than the heat load,the heat storage device stores the remaining heat,and when the heat production is lower than the heat load,the heat storage device releases heat to make up for the lack of heat supply.There are three common heat storage methods,explicit heat storage,latent heat storage and thermal storage.Latent heat storage refers to the material when the solid-liquid phase change large-scale absorption or release of heat process.This article is a study of phase change microcapsules under the latent heat storage method.In this paper,the phase change microcapsule is used as the material,the base fluid matched with the density of the phase change microcapsule is first configured,then the microcapsule is mixed with the base fluid,the phase change suspension with the mass concentration of 10%and 20%.The experiments were designed and designed for the purpose of heat exchange with hot water.Experiments were carried out under different phase suspension concentrations,different peristaltic pump rotational speeds,different water flow rates and different water inlet temperatures.The influence of each factor on the heat transfer coefficient of the whole casing heat exchanger is calculated.The experimental results show that the higher the mass concentration of the phase change suspension,the stronger the heat storage capacity.The heat storage capacity of 10%of the phase change suspension was 20.05%higher than that in the phase change segment,while the phase change suspension of 20%mass concentration increased by 41.25%compared with the base solution.And the higher the mass concentration of the phase change suspension,the higher the heat transfer coefficient of the whole casing heat exchanger.Phase transition of mass concentration of 10%suspension of casing heat exchanger heat transfer coefficient is the base and hot water heat exchanger heat transfer coefficient of 1.11 times,while 20%mass concentration of the phase change slurry pipe heat exchanger heat transfer coefficient is the base of 1.21 times of the heat transfer coefficient of heat transfer with the hot water.The experimental results of different peristaltic pump velocity indicate that the higher the velocity of phase change suspension,the higher the heat transfer coefficient of the casing heat exchanger.The heat transfer coefficient of the casing heat exchanger can also be improved by increasing the flow of water.Under different outer casing heat exchanger tube inlet temperature of the experimental results show that the change of inlet temperature of the phase change slurry tube heat exchanger heat transfer coefficient of influence is not big,can say the inlet temperature of water is not the important factors that affect the heat transfer coefficient of casing heat exchanger.