Viridian Solar Wind Load Calculator
description
Transcript of Viridian Solar Wind Load Calculator
Wind Loading Calculator
USE ONLY FOR VIRIDIAN SOLAR PRODUCTS
PROJECT
Project numberProject NameClient
INPUTS
SiteBasic wind speed (from map) 23 m/s
Site altitude above sea level 10 m
Distance from the sea 10 km
Location type town
Installation
Roof height 5 m
Parapet > 200mm high YesRoof Zone EdgePanel tilt angle 10 degrees
The roof edge zone width is 0.1 x the longest roof dimension
RESULTS
Fixed System Free-standing System
Peak force on each bracket per panel
Number of 450 x 600 x 50mm concrete slabs per panel
V20E or PV20 V20E or PV20 5.8Fh max 145 N V30E or PV30 8.8Fv max 481 NFv min -296 N Dead load on roof per panel (including panel and ballast tray)
V30E or PV30 Load Uniformly Distributed
Fh max 217 N V20E or PV20 259 kg 113
Fv max 709 N V30E or PV30 376 kg 164Fv min -457 N
Example
Version 1.2
Edit the values above to reflect those of the project under consideration.
The calculation is based on BS6399-2:1997. Viridian Solar has added no additional loading factors to the result. The coefficient of friction is assumed to be 0.4 (rubber/steel), topography is assumed to be insignificant. If in doubt, consult a structural engineer.
(dynamic plus static loads, double the value for bracket between two panels)
kg/m2
kg/m2
For a free standing system of 10 solar panels in a single row, it is calculated that the required number of concrete slabs is 7.7 per panel. The total number of slabs is therefore 7.7 x 10 = 77. 10 panels require (n+1) = 11 ballast trays, so the number of slabs per ballast tray is calculated to be 77/11 = 7
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Wind Loading Pressure for Solar Panel on Open Framework
BS 6399-2:1997 Loading for Buildings Part 2 : Code of Practice for wind loads
From Inputs PageSite Altitude 10 m above sea levelLocation townDistance from sea 10 km
Building Height 5 m
Include Internal Pressure 0
Vb 23 m/s
Site Wind SpeedVs = Vb x Sa x Sd x Ss x Sp
Sd - site direction factor - set to 1 when the orientation of the building is unknownSs - seasonal factor - set to 1 when the building is permanentSp - probability factor - set to 1 for 50 year stormSa - Site altitude factor = 1 + 0.001 x altitude in m
Vs = 1.01 Vb
Effective Wind SpeedVe = Sb x Vs
Sb is based on height of building and whether it is in the country or town
In country or up to 2km into townBuilding Distance to sea (km)Height < 0.1 2 10 >100 1
5 1.65 1.62 1.57 1.45 2
10 1.78 1.78 1.73 1.62 3
15 1.85 1.85 1.82 1.71 4
In townBuilding Distance to sea (km)Height < 0.1 2 10 >100 1
5 1.5 1.45 1.36 2
10 1.73 1.69 1.58 3
15 1.85 1.82 1.71 4
Sb 1.45
Ve = 1.4645 Vb= 33.6835 m/s
Dynamic Pressure
695 Pa
qs = 0.613 Ve2
qs =
External Pressure
Ca = 1 for an element as small as a solar panel
Cp,net from lookup table
From BRE Digest 489, Wind loads on roof based PV systems
Table 4 Pressure coefficients Cp,net for PV modules based on open support structures
Roof zoneNo Parapet Parapet >200mm
Cp min Cp max Cp min Cp maxCorner -1.8 1.2 -1.5 1Edge -1.6 1.2 -1.2 1Central -0.6 0.6 -0.6 0.6
Table 5 Pressure coefficients Cp,net for PV modules based on enclosed support structures
Roof zoneNo Parapet Parapet >200mm
Cp min Cp max Cp min Cp maxCorner -1.7 0.5 -1.7 0.5Edge -1.6 0.5 -1.2 0.5Central -1.0 0.5 -1.0 0.5
NotesEdge zone is L/10 wide, where L is largest plan dimension of roof.
Conservatively consider location to be an edge
Parapet 2Central/Edge/Corner 1
Cp min from table 4 -1.2Cp max from table 4 1
Pe min -835 PaPe max 695 Pa
Pe = qs Cp,net Ca
Imposed Loads on Roof Due to Wind Load
V20/PV20
Positive Pressure 695 Pa Negative Pressure -835 Pa
FH FH
242 - 290 F FV F FV
1,391 1,370 - 1,669 - 1,644
W W510.12 510.12
459 N 481 N -271 N -296 N
NOTES:Loads shown are for each side of each solar panel.There is a horizontal force to react as well as the vertical force.
Area 2 Area
Angle θ 10 degrees _Theta
Panel and frame weight 510 N _W
m2
θ θ