Re: [TRNSYS-users] Coldbridge Question

["Diego A. Arias" <daarias@wisc.edu>]

Dear Theodosiou,

I think that if you want to define a 'wall with cold-bridge effect', 
taking into account solar absorption at the surface, you should create a 
new wall, with a massless layer.  The resistance of this layer should be 
calculated taking into account the cold-bridges.
Otherwise, as you point out, you are defining a resistance element 
without gains on the surfaces.
Best regards,

Diego

Theodosiou wrote:
> As far as i can understand, thermal bridges in TRNBuild are not defined as
> "Walls with a coldbridge effect" like it can be found in the manual, but as
> a separate 1D element. My question is why the solar absorptance and surface
> coefficient  are needed since the total area of the element is zero (it only
> has length) and consequently there are no solar or convective gains.
>
> Regarding the resistance, is this value the same (actually the reverse) as
> the values mentioned in ISO14683 for the linear thermal resistance of
> thermal bridges?
> I am asking this because in chapter 6.2.4.2.5, figure 6.2.4-23, the thermal
> resistance is 45 hmK/kJ witch results in a Linear-Uval of 0.00617 W/mK !! In
> ISO14683 there are no such small linear values
>
>
> Thank you in advance
>
>
> T.Theodosiou
> Department of Engineering & Managment of Energy Resources
> University of Western Macedonia
> Kozani, Greece
>
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