Average Daily Shading Factor Variations with Aspect Ratios for Different Flat-Plate Collector Arrays

A model to calculate the average daily shading factor of flat-plate solar collector array installed on the limited horizontal roofs has been developed. The relations between the average daily shading factor and the aspect ratio of the collector array have been deeply studied. The results show that for the collector array with the floor area from 50 m2 to 1000 m2, the smaller the floor area, the faster the increase of the average daily shading factor with the increase of the aspect ratio. The average daily shading factors do not exceed 0.085 for the low latitude regions (lat. 30o N), whereas the maximum average daily shading factors can reach 0.140 when the latitude is close to 40o N.