System effect factors for various duct elbows
From ASHRAE (1988), with permission
Notes:
Square elbow with inlet transition -- No turning vanes
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R/H | No duct |
2D duct |
5D duct |
0.50 | 2.50 | 1.60 | 0.80 | |
0.75 | 2.00 | 1.20 | 0.66 | |
1.00 | 1.20 | 0.66 | 0.33 | |
2.00 | 0.80 | 0.47 | 0.26 |
Square elbow with inlet transition -- Three long turning vanes
R/H | No duct |
2D duct |
5D duct |
|
0.50 | 0.80 | 0.47 | 0.26 | |
1.00 | 0.53 | 0.33 | 0.18 | |
2.00 | 0.26 | 0.22 | 0.14 |
Square elbow with inlet transition -- Short turning vanes
R/H | No duct |
2D duct |
5D duct |
|
0.50 | 0.80 | 0.47 | 0.26 | |
1.00 | 0.53 | 0.33 | 0.18 | |
2.00 | 0.26 | 0.22 | 0.14 |