Re: [EnergyPlus_Support] Auxiliary Slab Program Questions

On Thu, Apr 21, 2011 at 9:45 AM, Jacob Dunn <arch.dunn@xxxxxxxxx> wrote:

Thanks for the response Linda.

Right, the "GroundHeatTransfer:Control" object was included in my .idf file, and it automatically ran the slab program. This outputs a "xxx.slab" file which contains a table with the "Monthly Slab Outside Face Temperatures". I think I have to "extract" these temperatures and put them in the "Site:GroundTemperature:BuildingSurface" object to use in subsequent runs.

Additionally, the Input Output document contains very little information on the "GrountHeatTransfer:xxx" objects, they are actually located in the "EnergyPlus Auxiliary Programs" reference guide.

Either way, this really didn't address any of my questions. Thanks for the response though! :-)

-jake

On Thu, Apr 21, 2011 at 7:29 AM, Linda Lawrie <linda@xxxxxxxxxxxxxx> wrote:

If you put the GroundHeatTransfer:* (especially GroundHeatTransfer:Control) in your input file, then it will automatically run the slab program.

Read about the rest of the requirements for using these in the Input Output document. You don't need to extract the temperatures -- the preprocessor ExpandObjects program will do it for you.

At 05:31 PM 4/20/2011, Jacob Dunn wrote:

Hello Everybody!

I just successfully ran the auxiliary Slab program and extracted the custom ground temperature profile from the ".slab" output file. I used the "GroundHeatTransfer:Slab:Insulation" object to define a slab-on-grade floor type with a typical six inch deep slab, 2 feet of horizontal (strip) R-10 insulation at the edge of the slab's extents, and R-10 vertical insulation 2 feet straight down.

My confusion is this: So now I have a ground temperature profile that I can plug into subsequent EnergyPlus runs that takes into account vertical and horizontal insulation, but the actual exterior floor construction object only has an R-10 insulation applied uniformly underneath its surface? The exterior floor construction does not take into account the perimeter insulation of the stem walls, so how is the actual floor construction communicating with the ground temperatures? Especially if the insulation parameters are not specified the same way within the energy plus regular program when compared to the auxiliary slab execute program?

So basically, I have the ground temperatures for a condition that I can't actually define in my energy plus model? It seems strange that I can define specific insualtion parameters in the "GroundHeatTransfer:Slab:xxx" objects, but this isn't taken into account in the regular way that EnergyPlus defines materials and constructions?   Does it even matter? If i just plug in the new ground temperatures am i good to go?

Thank you so much ahead of time for any help, let me know if clarification is needed!

--
Jake Dunn -LEED AP-

Research Assistant
Integrated Design Lab- Boise
University of Idaho
www.idlboise.com
arch.dunn@xxxxxxxxx

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--
Jake Dunn -LEED AP-

Research Assistant
Integrated Design Lab- Boise
University of Idaho
www.idlboise..com
arch.dunn@xxxxxxxxx