Study On Heat Transfer Performance Of Solar Chimney Based On Phase Change Thermal Storage

Natural ventilation is one of the most important technologies in improving air quality and decreasing energy consumption of air-conditioner in modern energy-efficient buildings. Ventilation of the solar chimney is a kind of natural way of ventilation under thermal pressure effect. Using solar radiation to heat the chimney air can not only provide buoyancy for the air but also enhance air movement in the chimney system. Besides,in the process of phase change, the phase change materials absorb and release a mass of energy. Applying this energy into enhancing natural ventilation, indoor temperature fluctuate range will decrease, and the air-conditioner operating time for building heating or cooling is reduced. Furthermore, the goal of upgrading indoor comfort and energy saving may come true.Solar wall is the key technology of solar chimney.In this paper, the PCM is used in solar ventilation, we can use of the PCM’s heat storage effect to use the solar energy shift from day to night. We achieve intermittent ventilation or heating. In this way, the solar ventilation system can be full-ventilation, and expanded the scope of application. So the research of solar Wall has very important significance.In this paper,Mathematical model of the LHTES system is developed. By using solidification/melting models and DO solar radiation model of Fluent software,by setting up the experimental platform under the natural environment,The simulation results were compared with the experimental results proved that the model reliability. Considering the nature convection in the liquid Phase and the hot media coupled with the unit, temperature field is obtained and Phase Change interface Position changing with time is still calculated,the results proved that the natural convection in the melting process of paraffin can’t be ignored.In order to optimize the heat transfer performance of the collector, the use of 3wt% carbon nanotubes / paraffin phase change heat storage device or shorten the rib spacing, through the simulation analysis, taking into account the nature convection in the liquid phase under the action of hot plate set, change rule of internal phase interface, temperature field, liquid fraction changes over time affect the use of two kinds of optimization methods. The simulation results show that, both of the two methods have a positive effect on the heat transfer characteristics of the heat collector, can melt ahead of time the heat collecting plate internal phase change material, ahead of 35 min and 20 min respectively.