| Energy is the foundation of national economic and social development,and also the inevitable requirement of social development and progress.Energy transformation is the only way to sustainable development.Phase change heat storage technology is an important technology which can not only solve the contradiction between energy supply and demand,but also improve the efficiency of energy utilization and protect the environment.Paraffin is a commonly used phase change material for heat storage.It not only has the advantages of high melting heat,stable performance and no corrosion,but also has rich resources and large reserves.However,due to the problems of small thermal conductivity,small unit density and poor heat storage capacity per unit volume,its application and development are limited.Strengthening the thermal conductivity of phase change material is an effective way to enhance the heat transfer of paraffin.Due to its high thermal conductivity,high porosity and high specific surface area,copper foam is widely used in heat transfer enhancement of paraffin wax.The research group has verified that the addition of foam metal copper can effectively enhance the heat transfer effect of paraffin wax.Therefore,this paper mainly studies the heat transfer effect of paraffin wax composite phase change material composed of foam metal copper in paraffin wax under different arrangement.Firstly,this paper introduces the composition,design and working principle of the traditional air source heat pump test-bed.The system is modified by adding a phase-change heat storage tank to form the working mode of partial condensation heat recovery of air source heat pump.Based on the principle of phase-change thermal storage,the effects of three different arrangements of foam metal Cu in the phase change heat storage tank are studied by means of experimental and numerical simulation.The main research work is as follows:Design three layout schemes of foam metal copper in phase change heat storage box.Combined with the characteristics of the three schemes,the fixed temperature acquisition point of the thermocouple is set.According to the sequence of the scheme,the experiment was carried out.By analyzing the temperature change of the temperature measuring point,we can draw the following conclusions: the three schemes have little difference in response time,and the heat storage rate starts to accelerate after 30min;in the middle stage of heat storage(30-210min),it is the fastest stage of temperature rise of the measuring point,the temperature of scheme I rises from 36.4 ? to 70.2 ?,and the temperature rise rate is0.20 ? / min,17.6% higher than that of scheme II,and 17.6% higher than that of schemeIII In the later stage of heat storage,the first scheme is to shorten the time of 50 min and enter the latent heat storage stage first.It can be seen that in scheme 1,the composite phase change material has the best heat storage effect and the fastest temperature rise rate.The performance of the system under three different schemes of foam metal copper is analyzed.The COP values,EER values,COPt and Rx performance parameters of the three schemes are compared and calculated.From the comprehensive comparison of the data,the different layout formulas of foam metal in the phase change storage tank do have certain effects on the performance of the system,and the layout effect of the scheme is two and the other.Case three is more effective.According to the three conservation laws,the physical model of the heat storage process of the phase change accumulator is established,and three experimental schemes in the phase change accumulator are simulated by COMSOL simulation software.By establishing a three-dimensional model,reasonably simplifying the model,setting the corresponding boundary conditions and initial conditions,strictly controlling the mesh quality and selecting the solver,analyzing the changes of liquid phase ratio and temperature field at different times in three cases,the following laws are obtained:... |
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