Re: [EnergyPlus_Support] Thermal Bridging

[TangoJim <TangoJim@xxxxxxxxx>]

The Composite Construction Dataset issued with V1.0.3
only list wall construction assemblies for the clear
section of a wall. The extra framing around the
windows, doors, corners, footers and headers is also
very significant in thermal bridging. In many cases,
it is more significant than the thermal bridging of
the clear wall section.

Fred Winkelmann wrote a routine to combine several
construction assemblies (clear wall, corners, footers,
headers, extra window and door framing) with each of
their conduction transfer functions together into a
composite "whole wall" construction assembly transfer
function for a special version of the DOE-2 program
written for the California Energy Commission. 

Reference: "DOE-2 Modeling of Two-Dimensional Heat
Flow in Metal Stud Walls", California Energy
Commission Pub. P400-98-010, November 1998, Vladimir
Bazjanac, Ph.D., Helmut Feustel, Ph.D., Joe Huang,
Fred Winkelmann, Ph.D. 

As a first step, I would like the EnergyPlus team
consider providing a similar routine for a future
release. The second step, would be to expand
individual composite assemblies for more construction
assemblies. This library would include equivalent
construction assembly layers for the clear wall,
corners, footers, headers and framing around the
windows similar to the work of Ashrae report RP-1145,
"MODELING TWO- AND THREE-DIMENSIONAL HEAT TRANSFER
THROUGH COMPOSITE WALL AND ROOF ASSEMBLIES IN
TRANSIENT ENERGY SIMULATION
PROGRAMS (1145-TRP)."  

 
--- Linda Lawrie <linda@xxxxxxxxxx> wrote:
> At 02:04 PM 2/6/2003, Edward Lyon wrote:
> 
> >You have 2 choices:
> 
> In addition to what Ned has suggested, you can look
> at the Composite 
> Construction Dataset that was issued with V1.0.3. 
> ORNL did a lot of 
> calculations with 3D models and came up with
> equivalent constructions that 
> allow building modeling with the equivalent u-values
> for constructions that 
> may have thermal bridging.  While this does not
> actually simulate the 
> problems that may occur with thermal bridging, it
> may help you simulate the 
> bulding appropriately.  References to other material
> regarding these 
> constructions is included in the Dataset file.  I
> believe a short 
> description also got put in the Output Details and
> Examples document for 
> the V1.0.3 release.
> 
> 
> Linda
> 
> EnergyPlus WebSite: http://www.energyplus.gov
> Owner: EnergyPlus_Support list
> Member: EnergyPlus Development Team
> 
> 
> 


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