Re: [TRNSYS-users] Determining TrnBuild Boundary temperatures in boundary type.

Muhammad and Tim,

in fact it is a little different:

Boundary identical

- the back surface receives the same gains as the front side surface

- the starnode temperature of the back side is the starnode temperature of the front side

- the used heat transfer coefficient

If the construction is symmetrical and the heat transfer coefficients (htc) are the same then
the back surface temperature = front surface temperature.

If the construction isn’t symmetrical and/or different htc are defined the temperatures are different.

Boundary userdefined

- The user defines a temperature which is coupled to the back surface temperature by the
defined htc to the back surface temperature.

If you want to set a defined back surface temperature there is an option to define “direct contact”
by setting htc = 0.0001. I know that it is strange to defined a very low HTC for obtaining perfect coupling,

But that’s the way it is defined in the code.

Marion

-----------------------------------------------------------------------------------------------------------------------------------------------------------

Dipl.-Ing. Marion Hiller
TRANSSOLAR Energietechnik GmbH
Stuttgart - Munich - New York - Paris

t: +49.711.67976.0 f: +49.711.67976.11

www.transsolar.com/

KlimaEngineering - Technologien für energieeffizientes Bauen und Nutzerkomfort in Gebäuden
Transsolar Energietechnik GmbH, Curiestrasse 2, 70563 Stuttgart

Amtsgericht Stuttgart - HRB 23347 / Steuernummer: 99073/00911 / USt-IdNr.: DE 152272639
Geschäftsführer: Matthias Schuler, Thomas Auer, Stefan Holst, Dieter Schnelle

Von: TRNSYS-users [mailto:trnsys-users-bounces@lists.onebuilding.org] Im Auftrag von mcdowell@tess-inc.com
Gesendet: Donnerstag, 2. Juli 2015 22:59
An: TRNSYS users mailing list at OneBuilding.org
Betreff: Re: [TRNSYS-users] Determining TrnBuild Boundary temperatures in boundary type.

Muhammad Talha -

Identical means that the back surface temperature is the same as the front surface temperature.

Userdefined means that the back surface temperature will be set by the user, either as a constant or as an input.

Regards,

Tim

---
Timothy P. McDowell

Executive Vice President

Thermal Energy System Specialists, LLC

22 N Carroll St, Suite 370

Madison, WI 53703

608-274-2577

On 2015-07-02 15:30, Muhammad Talha wrote:

Dear TRNSYS users,

Is there a way to determine the boundary temperature in the boundary type in TrnBuild. I am using the boundary as category for floor but can't comprehend what identical means. I want to determine heat loss through the floor of my building.

Mohammad Talha
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