Oak Ridge National Laboratory has done
good work on modeling two-dimensional heat flows through exterior
walls, although mostly 10-20 years ago.
Some of their results have been simplified and written up in the ASHRAE Handbook of Fundamentals, although I haven't checked in the current version of the HOF.
Ken Childs et al. has also developed the HEATING 7 program that can be used to calculate steady-state U-values or heat flows for composite walls, corners, or edges.���� Jan Kosny (now at the Fraunhofer Institute) has also developed a method to create a fictitious 1-dimensional layer of three that would produce the same heat flows in a dynamic simulation.
Back in 1987, I also worked with other researchers at LBNL to develop the WALFERFN (WALl Finite Element Response Factor (New)) program that calculates equivalent one-dimensional response factors for composite walls and writes them directly into the DOE-2 response factor library.
These are not kludges, but mathematically as rigorous as the standard 1-dimensional transfer functions used in EnergyPlus.���� The only question in my mind is what it would take to have EnergyPlus utilize the results of these programs.���� For those interested, I would be happy to share more details about WALFERFN.���� For those interested in the Oak Ridge work, I'd suggest you contact Ken at ORNL or Jan at the Fraunhofer Institute.
Joe
On 10/16/2013 7:44 AM, Andres Zupfer wrote:
Some of their results have been simplified and written up in the ASHRAE Handbook of Fundamentals, although I haven't checked in the current version of the HOF.
Ken Childs et al. has also developed the HEATING 7 program that can be used to calculate steady-state U-values or heat flows for composite walls, corners, or edges.���� Jan Kosny (now at the Fraunhofer Institute) has also developed a method to create a fictitious 1-dimensional layer of three that would produce the same heat flows in a dynamic simulation.
Back in 1987, I also worked with other researchers at LBNL to develop the WALFERFN (WALl Finite Element Response Factor (New)) program that calculates equivalent one-dimensional response factors for composite walls and writes them directly into the DOE-2 response factor library.
These are not kludges, but mathematically as rigorous as the standard 1-dimensional transfer functions used in EnergyPlus.���� The only question in my mind is what it would take to have EnergyPlus utilize the results of these programs.���� For those interested, I would be happy to share more details about WALFERFN.���� For those interested in the Oak Ridge work, I'd suggest you contact Ken at ORNL or Jan at the Fraunhofer Institute.
Joe
On 10/16/2013 7:44 AM, Andres Zupfer wrote:
����Thanks for the quick help. Of course a static simulation is sufficient for 99% of the cases.����I will go for the subsurfaces option, it seems the most logical solution.Greetings,Andres
On Tuesday, October 15, 2013 3:24 PM, Jon Hand <jon@xxxxxxxxxxxxxxxxx> wrote:
����
Thermal bridges - well you could do a kludge or you could use a tool such
as ESP-r which includes descriptive terms for linear thermal bridges for
each surface-edge junction and which includes their impact in the energy
balance. Ok it is a static representation rather than fully dynamic one
but folk in Europe tend to be paranoid about thermal bridges ;-)
Regards, Jon Hand, ESRU, Glasgow Scotland.
________________________________________
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [EnergyPlus_Support@xxxxxxxxxxxxxxx]
Sent: 15 October 2013 14:09
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Digest Number 4271
De: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] En nombre de Andres Zupfer
Enviado el: lunes, 14 de octubre de 2013 14:11
Para: EnergyPlus_Support@xxxxxxxxxxxxxxx
Asunto: [EnergyPlus_Support] Modeling of Thermal Bridges ?
Hi all,
when entering the construction of the external walls the thermal bridges are neglected.
However for some buildings this can be a significant error. Therefore I am looking for the best way to include the psi-value (calculated with external program like THERM or HEAT) into the construction.
A quick and dirty solution would be to change the thermal insulation of the wall accordingly (i.e. change the thermal conductivity of one or some materials). However this could be tedious because it might be different for each room, so I get a lot of new pseudo-constructions in to my idf file.
Does anyone have a good solution for this?
Thanks,
Andres
__._,_.___
Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx
The primary EnergyPlus web site is found at:
http://www.energyplus.gov
The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/
Attachments are currently allowed but be mindful that not everyone has a high speed connection. Limit attachments to small files.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
![]()
Your email settings: Individual Email|Traditional
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe
__,_._,___