BC Hydro has some great resources for determining the effects of thermal bridging. The BC Hydro New Construction Program mandates that all thermal bridging be
accounted for in both the proposed and baseline models. They have issued a spreadsheet for calculating all the thermal bridging. See the Resources section on this web page:
https://www.bchydro.com/powersmart/business/programs/new-construction.html#thermal
There is a full working example included in that Resources section.
Christopher Jones,
P.Eng.
Senior Engineer
WSP Canada Inc.
2300 Yonge Street, Suite 2300
Toronto, ON M4P 1E4
T +1 416-644-4226
F +1 416-487-9766
C +1 416-697-0056
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]
Sent: Tuesday, May 24, 2016 3:14 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Thermal Bridge
Julian is correct. Some third party GUIs do this for you so that you can input psi-values. They then use the linear thermal bridging values to either
1) derate the construction u-values by decreasing the insulation layer untill the equivalent u-value for the assembly is reached, or
2) they create a subsurface on the base surface with increased u-value to achieve the same equivalent area-weighted u-value for the assembly.
The second method may be a better indicator for condensation analysis on "cold spots" but is still not as good as using a FEM method (like from THERM).
The more surfaces your model has, the more computation time you will need, so the first method is better for speed.
Hope this helps,
Jean
On 23 May 2016 12:31 pm, "gauravciitr@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
Hi,
What objects do we have to design thermal bridge in a building? Where can I put value of phi?
Thanks
Gaurav
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