阳台壁挂式太阳能集热器件遮挡因子的研究

针对太阳能集热器件与中高层建筑阳台大角度(≥60°)集成后,夏半年上层集热器件对下层集热器件的遮挡问题,该文建立了日均遮挡因子的计算模型。利用此模型对夏半年各月代表日日均遮挡因子进行了计算,并对日均遮挡因子与纬度、倾角、方位角的关系进行了深入的讨论。结果显示,夏半年各月日均遮挡因子以正南方向为最大,向东西方向呈对称分布。方位角在±20°内,日均和夏半年平均遮挡因子变化较小。随着纬度和倾角的增大,各月日均遮挡因子逐渐减小。集热器件60°与阳台集成时,北纬20°日均遮挡因子最大约为0.34;北纬35°时,日均遮挡因子≤0.087。夏半年的平均遮挡因子均小于0.173。方位角太大不利于太阳能的接收,集热器件的方位角应控制在±20°以内。为便于应用,该文给出了夏半年平均遮挡因子与方位角高相关性(R2≥0.99)的关系式。

Study on shaded factor of balcony wall solar collector unit

After solar collector unit integrating into balcony of high-rise buildings with large tilt angle(≥60°),the lower solar collector unit will be shaded by the upper one.The calculation model of the daily shaded factor has been developed in this paper.Daily shaded factor of representative days in summer months has been calculated by using this model and the daily shaded factor variations with latitude,tilt and azimuth have been analyzed and discussed.The results show that the maximal daily shaded factors of representative days in summer months appear at due south and they are approximate symmetrical distribution between East and West directions.Daily shaded factors and average shaded factors of summer months change smoothly at the azimuth angle range of[-20°,20°].Daily shaded factors decrease with the latitude and tilt angles increase.When solar collector units used at 20°N are integrated into the balcony at 60°,their maximal daily shaded factor is around 0.34;the daily shaded factors do not exceed 0.087 if the latitude equals to 35°.For all summer months,the average shaded factors are below 0.173.The azimuth angle should be controlled in[-20°,20°]because large azimuth angle will reduce solar energy absorbed by the solar collector unit.For the sake of engineering applications,correlations with a high correlativity(R 2 ≥0.99)of average shaded factors and azimuth angles have been given in this paper.