What I need may seem basic, but I hope someone can help. At my first seminar I was saddled with an un-cooperative laptop and my second seminar dealt with different but equally interesting software and I did not want to slow class down with basics. The fact that I am an architect and not a physicist does not help.
I am looking at 3 wall assemblies in WUFI 5.1. All 3 consist of metal stud back-up of a brick veneer, all with a 2" air cavity, glass matt GWB sheathing at exterior and standard 5/8" interior GWB at interior. Calculation run times are for 2 years in Pittsburgh, Pa. The 1st wall has fiberglass batt insulation at stud cavities and an SBP membrane (Tyvek) over the exterior sheathing. The 2nd wall has 2" EPS insulation over exterior sheathing that has a spray applied air/vapor barrier over it, with no fiberglass batt at the stud cavity. The 3rd wall is the same as the second, except the stud cavity is also filled with batt insulation.
I ran calculations for all walls cut through the stud cavity, so thermal bridging is not an issue, I may look at that issue in WUFI 2-D. Anyway, on first case with fiberglass batt only I get 82 convergence failures which seems like alot. I increase the fineness of the grid and I get 110 but in both instances Balance 1 and 2 are identical. The other cases seem to be within reason with respect to convergence errors of 5 to 11, & balance 1 and 2 are equal. Balance seems awfully low, 0.2441 kg/m2 . Do these results sound reasonable?
Convergence errors & results reliability
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Manfred Kehrer
- WUFI International Support Team
- Posts: 351
- Joined: Thu Mar 10, 2005 2:17 am -1100
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.... It is easy and complex.