| The accurate prediction of wind load of PV panels is of great significance to the wind-resistant design of PV system.In the current related research and load specifications,the wind load coefficient standard for roof PV arrays is given,but the impact of changes in the roof wind field environment is not considered.For this reason,the wind load of the roof PV array is studied and analyzed under the influence factors of different array parameters and building shapes,which provides theoretical guidance for the wind resistance design of PV panels,and has important engineering significance.In this paper,CFD software is used to simulate the atmospheric boundary layer,and the wind load data of the original size PV panel are compared with the wind tunnel test results to verify the reliability of the numerical simulation method.On this basis,the influence of the related parameters of PV array,wind angle,building shape and disturbing buildings on roof flow field are studied,the distribution characteristics of net load effect and overturning effect of PV panel under different affecting factors are summarized.The main conclusions are as follows:(1)The research on the influence of PV panel location,height,tilt angle and wind angle on the roof flow field and the array wind load distribution shows that the wind load of the PV array is not only affected by its local flow,but also the influence of roof eddy can’t be ignored.In the middle-rear zone of the roof(c/B=0.6～0.8),the net load and overturning effect of the inner and outer PV panels are not strong.The increase in the height h from the lowest point of the PV panel from the roof causes the net load effect of the PV panel on the windward side to weaken.The overturning effect of each PV panel is the weakest when h=0.With the increase of the tilt angle of the PV panels(α=15°～45°),the overturning effect continues to weaken in the tailwind condition,and in the case of leeward wind,only the row-1 of PV panels at the tilt angle α<30°,the net load effect shows an increasing trend.With the increase of wind angle(θ=0°～180°),the net pressure coefficient of each PV panel increases first,after decreases and increases again.The peak net load of the row-1 of PV panels is the strongest,mainly concentrated at wind angles of 15°～30° and 135°～165° nearly,and the peak net load decreases continuously follow the wind direction.The overturning effect is the strongest in leeward condition,especially near θ=120°～165°.The above conclusions provide a reference for practical engineering application.(2)The flow field and array wind load distribution on the cubic,concave,convex,L and stepped roofs are studied and compared.The results show that the infuse airflow near the characteristic shape of the roof is the main reason for the variation of the roof vortex and the local vortex of the array.The net load and overturning effect of PV panels in both sides of concave roof array and in the middle of convex roof array are significantly enhanced compared with cube building condition,and the peak wind load of array in convex building condition is the strongest.The above results show that the influence of building shape on wind load of PV array can’t be ignored,especially for concave and convex buildings.In practical engineering application,the wind load standard of concave and convex building roof PV array should be revised.In the future research,it is necessary to consider the influence of the shape of the building,and distinguish it from the cube building,in order to reasonably analyze the wind load of the roof array.(3)The influence of location and related dimensions of roof building and shelter building on array wind load is studied.The results show that the wind load effect of PV panels is significantly enhanced while the roof building is located at 1/4 location in the roof leading edge zone or near the roof side edge in the roof middle zone.It is suggested that the roof in these two conditions should not be selected in practical engineering application.The influence of the roof building on the wind load of PV array can be effectively reduced while the roof building is located near the central axis of the roof and the height ratio m/H is about 0.15.The wind load distribution of the array is relatively uniform when the offset distance ratio of the sheltered building is y/L=0.4～0.5.The increase of the length-width ratio of the sheltered building mainly results in the weakening of the net load of the row-1 PV panels and the enhancement of the overturning effect of the row-2 PV panels.It is suggested that the length-width ratio of the sheltered building should be small and the offset distance ratio γ/L about 0.4～0.5,which can effectively improve the security of PV array.Figure[51]table[10]reference[60]... |
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