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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----- 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@put.poznan.pl] Gesendet: Donnerstag, 12. Juli 2012 18:25 Betreff: [TRNSYS-users] cold bridge _______________________________________________ TRNSYS-users mailing list https://mailman.cae.wisc.edu/listinfo/trnsys-users |