Study On Thermal Characteristics Of Phase Change Material Wallboard Coupling With Solar Energy

With the development of society and the improvement of living standard,building energy consumption is increasing sharply in recent years,which means that it has become urgent to promote energy conservation.The application of phase change energy storage technology in buildings can significantly smooth the indoor temperature fluctuation,improve the thermal comfort and reduce the building energy consumption.In this paper,phase change material was fabricated firstly,and then was molded into composite phase change material wallboard.Combined with building envelope,the cold storage and heating tests were conducted on phase change material wallboard,aiming to study its potential and advantage in building energy saving.Paraffin 25# and expanded perlite were selected as the phase change material and the supporting material respectively.And a great number of phase change particles were prepared by vacuum heating roller box,on which the DSC,SEM,FTIR and TG tests were conducted.Then,the phase change particles were molded into phase change material wallboard and the mechanical properties and the thermal storage-release properties tests were conducted.The results show that phase change material wallboard maintains both high thermo-physical properties and good mechanical compressive properties.Under summer conditions,the phase change material wallboard was combined with building envelope to set up phase change experimental rooms.And the cold storage performance test was conducted under the strategies of natural cold storage by closing the door and windows,natural convection with time by opening the door and windows at certain times,and natural convection with temperature by opening the door and windows at certain temperatures.The results indicate that attenuation and delay occurs in the phase change room under all the three strategies.Besides,the cold storage effect under the strategy of natural convection with temperature is the best,followed by that under the strategy of natural convection with time,and that under the strategy of closing the door and windows is the worst.Under winter conditions,in order to maintain the indoor thermal comfort,heat was stored within the phase change material wallboard via the capillary tubes embedded in the wallboard by using solar energy as the heat source and water as the medium.In addition,the experiments on thermal properties of phase change material wallboard,heating effect of solar energy as heat source,and systemic energy conservation under the premise of maintaining indoor thermal comfort,were conducted respectively in the phase change room and the reference room.The results demonstrate that the temperature fluctuation of the phase change room is far smaller than that of the reference room due to the thermal-storage and temperature-regulated effect of phase change material wallboard in the phase change room when heating both the phase change room and reference room by solar energy;the temperature of the phase change room is much higher than that of the reference room due to the solar energy as heat source in the phase change room when heating the phase change room by solar energy,which proves the feasibility of solar energy serving as the heating source;under the condition of adding auxiliary heat source,this system can maintain the indoor minimum temperature within the human comfort degree,and the power consumption of the phase change room was 3.06 kW·h lower than that of the reference room on average per day.Moreover,the heat transfer process of the phase change room was analyzed as well.The results show that heat transfers from the wall with heat source to the outside in the daytime,and transfers from the wall to the indoor room when the room temperature was lower than the phase change temperature.The above research finds that the phase change material wallboard,as an energy storage component,can not only improve the thermal inertia of the building envelope,but also can transfer heat with time and recycle it,indicating a great potential and advantage in energy saving.