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Re: [EnergyPlus_Support] How the slab preprocessor works?



I'll let Neal explain his work, but here is the link to Kiva http://bigladdersoftware.com/projects/kiva/

As far as I understood it, it's still a standalone tool (preprocessor) but given how quick it seems to be, maybe it could be integrated in E+ (as an option, just like you can change the conduction algorithm) for coupled simulation out of the box. The modeler could then choose if the added accuracy is worth the extra simulation time. Just my two cents.

Julien

Envoyé de mon iPhone

Le 24 mars 2016 à 10:40, "Joe Huang YJHuang@xxxxxxxxxxxxxxxxxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> a écrit :

 

I haven't looked at the Slab preprocessor in detail, but it seems to me that your case can be handled if you are able to do the following:
(1) iterate between the preprocessor and EnergyPlus to converge on the average monthly indoor temperature
(2) model a sufficient amount of soil outside the slab or basement wall in EnergyPlus to handle the daily cycle of heat flows
and
(3) extract the soil temperature from the Slab preprocessor not at the slab/soil boundary, but at the above-defined (slab + soil)/soil boundary.

When I did ground heat transfer in DOE-2, I always included as much soil as allowed by the Response Factor calculation for this purpose (5.25 ft if the slab was modeled as a single layer, down to less than 2 ft if the slab was insulated).

The point is to let the Slab preprocessor handle the 2-D/3-D heat flows and those with time constants greater than  a few days, and let EnergyPlus handle the quicker 1-D heat flows less than a few days.

All in all, though, I still think a coupled solution is the best way to go.  I was under the impression that Neal Kruis is working to do that in EnergyPlus.

Joe

Joe Huang
White Box Technologies, Inc.
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On 3/23/2016 7:45 AM, 'Edward G. Lyon' eglyon@xxxxxxx [EnergyPlus_Support] wrote:
 

From my experience the one thing you will not find in the documentation is that the preprocessor works best when the space is always mechanically conditioned.  I could not use it to calibrate a model of a space with no heating or cooling where the floor actually stored energy during the day and released it back to the space at night.

 

Ned Lyon, P.E. (MA, WV)
Staff Consultant

SIMPSON GUMPERTZ & HEGER
781.907.9000 main
781.907.9350 direct 
617.285.2162 mobile 
781.907.9009 fax
www.sgh.com

 

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]
Sent: Tuesday, March 22, 2016 7:49 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] How the slab preprocessor works?

 

 

Hello everyone,

My goal is to find out how the slab preprocessor works and what degree of influence of their input data.

Is there any manual slab preprocessor about your simulation procedure or someone has some paper/example that can help me?

 

Thanks you all

 

Vanessa Caieiro

 



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Posted by: Julien Marrec <julien.marrec@xxxxxxxxx>


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