Study On The Performance Of Prefabricated Solar Energy Collector And Storage Unit

The use of coal in winter heating in Area of Beijing ferry look forward to rural areas is one of the important factors to induce regional haze.It is an inevitable trend to replace the supply of scattered coal with clean energy.Therefore,the traditional solar air heating system is optimized to improve its heat collecton efficiency.Adding heat storage device to ensure nigt heat demeand by collecting waste heat,which is of great significance to promote the clean heating in rural areas of northern China in winter.Based on the traditional solar air collector,a new type of assembly solar air standardized heat collection and storage unit is designed.The performance of the unit is studied and optimized by CFD simulation software.Firstly,the open metal partition is added to the traditional plate solar air collector,and the single channel heat collecting unit in Shijiazhuang area is simulated.The results show that when the metal partition is added,the central staggered opening method is adopted,the opening size is 40 mm,and the center distance of the opening is 100 mm,the heat collection efficiency can reach 68.2 %,and the heat transfer factor is 0.6.In order to improve the heat collection efficiency,a double channel structure including fresh air passage and indoor return air channel is designed.The results show that the heat collection efficiency can reach 84.6 %and the heat transfer factor is 0.7 when the inlet velocity of new and return air is 1m/s and 0.5 m/s respectively.Secondly,in order to further improve the solar energy guarantee rate of solar air heating system,the air heat storage unit is set up in the device,and the heat collection and heat release process of paraffin heat storage units with different structures is studied.The results show that the heat transfer capacity of the air pipe can be enhanced by adding inner rib on the air channel of the heat storage unit,and the heat transfer between the heat storage duct and paraffin can be enhanced by adding the external rib.The selection of the heat release speed should be determined according to the length of the heat release time.Thirdly,in order to verify the comfort of the system,the indoor environment with different number of heat storage units is simulated.The results show that when three heat collecting and storage units are arranged on the south wall,the solar energy guarantee rate reaches 44.5 %.In the daytime heating stage,the average temperature of the active area at 1.2 m away from the ground is higher than 300.2 K;in the night,the average temperature of the location is higher than 288.2 K,which can basically satisfy the requirements of indoor heating needs.Finally,in winter heating period,the operation strategy of the system is to open the operation mode of heat collection and storage heating from 10:00 to 16:00 in the daytime,and the exothermic heating mode is started at 17:00-21:00 in the night,and the auxiliary energy heating mode is opened in other periods and when the heating demand is not met to ensure that the indoor heating demand is met.