[TRNSYS-users] Building a greenhouse in TRNSYS

David BRADLEY d.bradley at tess-inc.com
Thu Sep 16 20:33:12 PDT 2021


Paris,

   If you ignore one or more walls then in essence you have assumed that 
those walls are adiabatic and don't transfer any energy. An open or 
screened "wall" will transfer quite a lot of energy but primarily by 
convection. I would account for the wall and make it a single massless, 
low thermal resistance layer then spend some time working out how much 
infiltration air is going to come through that wall.

   As for the floor, a building sitting on ground will still transfer 
some energy to/from the ground beneath. I'd treat the floor of your 
greenhouse as some thickness of soil (perhaps 5-10cm) and as a BOUNDARY 
surface in TRNBuild. There are a few accepted methods for determining 
the temperature of the ground beneath the thin soil layer. You might 
look at the use of Type49; it is probably the most rigorous in your case.

kind regards,

  David


On 09/16/2021 14:18, Paris Pasqualin via TRNSYS-users wrote:
>
> Hello everyone,
>
> if I create a building in trnbuild and I don’t add a wall on certain 
> direction, does trnbuild understand that there is no wall and will 
> make the calculations based on that? The same goes for the flour. To 
> be more specific, I have to build a greenhouse and on one side the 
> greenhouse is open and covered with an insect proof net (which 
> shouldn’t have any effect on the thermal calculations). The greenhouse 
> also doesn’t have a floor. Can I create the greenhouse without adding 
> the wall and the flour or I should adopt some “tricks”?
>
> Best regards,
>
> Paris
>
>
> _______________________________________________
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> TRNSYS-users at lists.onebuilding.org
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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
3 North Pinckney Street - suite 202
Madison, WI  53703 USA

P:+1.608.274.2577
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com

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