[TRNSYS-users] cold bridge

[Karol Bandurski]

Dear Marion,

 

Thank you very much for your explanation!

 

If I understand:

 

1) You recommend to set resistance of whole wall (include cold bridge) in
"cold bridge window" (hmK/kJ) or resistance of "massless wall" (hm^2K/kJ).
It doesn't matter which way will be chosen, dimension of element will be the
same and only units will change m<->m^2.

 

2) In both case element will be massless. So what can I do to account mass
and heat capacity of wall and cold bridge?

 

Regards,

Karol

 

 

-----Original Message-----
From: Marion Hiller [mailto:hiller at transsolar.com] 
Sent: Friday, July 13, 2012 9:03 AM
To: karol.bandurski
Cc: trnsys-users
Subject: AW: [TRNSYS-users] cold bridge

 

Dear Karol,

 

If you define a "cold bridge" in TRNbuild the following happens:

 

- Instead of defining layers as for a wall you define a "thermal resistance"

(without mass effects) 

 

- Instead of setting an area as for a wall you define a lenght

 

However, in the end this cold bridge is treated as "a massless wall".

 

 

If you use a detailed radiation mode, you can't add surfaces (and a cold
bridge would be surface somehow) in order to keep the geometry consistent. 

 

It is not recommended to draw very small surfaces in T3d to represent the
cold bridge unless you need the inside surface temperature because very
small surfaces may cause trouble for matrix generation.

 

Therefore, the recommendation is to integrate the losses of a cold bridge
into the wall by adjusting the u-value of a wall as previously mentioned by
Adrien.

 

I hope this helps.

 

Best regards,

 

Marion

 

 

Dipl.-Ing. Marion Hiller

TRANSSOLAR: KlimaEngineering - Technologien für energieeffizientes Bauen und
Nutzerkomfort in Gebäude Munich - New York - Stuttgart + 49.711.67976.0 

 

Transsolar Energietechnik GmbH, Curiestrasse 2, 70563 Stuttgart Amtsgericht
Stuttgart - HRB 23347, Steuernummer 99073/00911, USt-IdNr.: 

DE152272639

Geschäftsführer: Dipl.Ing. Matthias Schuler, Dipl.Ing. Thomas Auer,
Dipl.Phys. Stefan Holst, Prof. Dipl.-Ing. Bleicher 

 

 

-----Ursprüngliche Nachricht-----

Von: Karol Bandurski  <mailto:[mailto:karol.bandurski at put.poznan.pl]>
[mailto:karol.bandurski at put.poznan.pl] 

Gesendet: Donnerstag, 12. Juli 2012 18:25

An:  <mailto:trnsys-users at cae.wisc.edu> trnsys-users at cae.wisc.edu

Betreff: [TRNSYS-users] cold bridge

 

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