[TRNSYS-users] cold bridge

Marion Hiller hiller at transsolar.com
Fri Jul 13 01:13:15 PDT 2012


Dear Karol,

 

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.

 

No, you need the thermal mass. The adjustment really depend on your wall
construction.

It is more adjusting the u-value of layer (if poassible) and thereby of
a wall.

For a wall with insulation I would increase the u-value for the
insulation such that it includes the loss of the cold bridge.

 

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 

 

 

  _____  

Von: Karol Bandurski [mailto:karol.bandurski at put.poznan.pl] 
Gesendet: Freitag, 13. Juli 2012 10:06
An: Marion Hiller
Cc: 'trnsys-users'
Betreff: RE: [TRNSYS-users] cold bridge

 

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:karol.bandurski at put.poznan.pl] 

Gesendet: Donnerstag, 12. Juli 2012 18:25

An: trnsys-users at cae.wisc.edu

Betreff: [TRNSYS-users] cold bridge

 

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https://mailman.cae.wisc.edu/listinfo/trnsys-users

 

 


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