[TRNSYS-users] small mass flow in TABS
David BRADLEY
d.bradley at tess-inc.com
Tue Jun 5 07:57:30 PDT 2018
Karol
My apologies; I forgot to mention one very important thing! When you
segment a floor you're essentially adding more surfaces to the zone.
Therefore you cannot use the "3D Data" zone geometry mode nor the
detailed radiation modes. Open the zone/airnode window for the zone in
question and take the following steps:
1. click on the "Radiation Mode" button and switch everything to the
"standard" model.
2. click on the "Geometry Modes" button then switch from "3D Data" to
"manual."
3. go back to the radiant floor specification and you should be able to
activate the segmentation.
Because of the need to shift away from detailed radiation models
(which may be quite important to your model) it might be worth looking
at the restrictions on the floor model with regards to how the pipe
spacing and layer thicknesses affect the minimum allowable flow rate.
Perhaps there are some modifications that you can make to the flow rate
or the piping configuration so that you can keep the detailed radiation
models.
kind regards,
David
On 06/05/2018 02:22, Karol Bandurski wrote:
>
> David,
>
> When I do what you advise then TRNBuild give information that it is
> impossible (enclosed)
>
> I will sent you also B17 file to allow that you could check it on
> yourself.
>
> Regards,
> Karol
>
> *From:*David BRADLEY [mailto:d.bradley at tess-inc.com]
> *Sent:* Monday, June 4, 2018 11:12 PM
> *To:* Karol BANDURSKI; 'TRNSYS users mailing list at OneBuilding.org'
> *Subject:* Re: [TRNSYS-users] small mass flow in TABS
>
> Karol,
>
> In the screencap that you sent it is the value currently set to 10
> that you need to adjust. The model is saying that as long as the flow
> rate to the floor is greater than 9.09 kg/h.m2 (1229.52 kg/h) then you
> don't need auto segmentation. If you want a lower flow rate than that
> (for example 8 kg/h.m2) then change the value currently set to 10 to 8
> and you should then have the ability to segment the floor. The number
> of loops has a minor impact on the allowable flow rate.
>
> kind regards,
>
> David
>
> On 06/04/2018 13:58, Karol BANDURSKI wrote:
>
> David,
>
> Both this errors have appeared when I decrease mass flow rate two
> times and increase number of loops 10 times…
>
> I don’t know way, but I don’t have option “autosegmentation”
> (print screen enclosed)…
>
> It seems to me that increase of loops number has not change
> minimum allowed mass flow rate.
>
> Kind regards,
>
> Karol
>
> *From:*David BRADLEY [mailto:d.bradley at tess-inc.com]
> *Sent:* Monday, June 4, 2018 7:06 PM
> *To:* TRNSYS users mailing list at OneBuilding.org
> <trnsys-users at lists.onebuilding.org>
> <mailto:trnsys-users at lists.onebuilding.org>;
> trnsys-users at cae.wisc.edu <mailto:trnsys-users at cae.wisc.edu>
> *Cc:* Karol Bandurski <karol.bandurski at put.poznan.pl>
> <mailto:karol.bandurski at put.poznan.pl>
> *Subject:* Re: [TRNSYS-users] small mass flow in TABS
>
> Karol,
>
> I do not think that the problem with the matrix inversion and
> the low flow rate in the active layer are necessarily related. I'm
> not sure what to suggest about the matrix inversion. The active
> layer model has a minimum allowable flow rate that is based on
> pipe spacing, the thickness of the layer(s) in which the pipes are
> embedded and the area of the floor. If you want to give a lower
> flow rate then you need to segment the floor, which means treating
> the floor like it was a few floors in series. Enter the desired
> minimum mass flow rate in the active layer definition screen. If
> it is below the minimum "allowed" mass flow rate then you'll have
> the option to segment the floor.
>
> kind regards,
>
> David
>
> On 06/04/2018 01:58, Karol Bandurski via TRNSYS-users wrote:
>
> Dear Experts
>
> I have problem with simulation TABS with specific mass flow
> rate about 5.4 kg/hm2.
>
> There are two errors:
>
> 1)Specific fluid mass flow of active layer in surface 894
> below minimum value of 8.90 kg/m2h Please, increase the
> minimum mass flow rate or use the autosegmentation feature of
> TRNBuild for subdividing the surface.
>
> 2)Subroutine INVERT was called from subroutine INVPAR with a
> singular matrix!
>
> I have increase number of loops 10 times but nothing change…
>
> It is possible to do simulation with so low mass flow rate?
>
> Kind regards,
> Karol
>
> --------------------------------------------------------------------
>
> Karol BANDURSKI M. Sc.
>
> Faculty of Civil and Environemntal Engeneering
>
> Division of Heating, Air Conditioning and Air Protection
>
> Poznan University of Technology
>
> https://www.researchgate.net/profile/Karol_Bandurski
>
> www.put.poznan.pl/~karol.bandurski
> <http://www.put.poznan.pl/%7Ekarol.bandurski>
>
>
>
>
>
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>
>
>
> --
>
> ***************************
>
> David BRADLEY
>
> Principal
>
> Thermal Energy Systems Specialists, LLC
>
> 22 North Carroll Street - suite 370
>
> Madison, WI 53703 USA
>
>
>
> P:+1.608.274.2577
>
> F:+1.608.278.1475
>
> d.bradley at tess-inc.com <mailto:d.bradley at tess-inc.com>
>
>
>
> http://www.tess-inc.com
>
> http://www.trnsys.com
>
>
>
> --
> ***************************
> David BRADLEY
> Principal
> Thermal Energy Systems Specialists, LLC
> 22 North Carroll Street - suite 370
> Madison, WI 53703 USA
> P:+1.608.274.2577
> F:+1.608.278.1475
> d.bradley at tess-inc.com <mailto:d.bradley at tess-inc.com>
> http://www.tess-inc.com
> http://www.trnsys.com
--
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI 53703 USA
P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com
http://www.tess-inc.com
http://www.trnsys.com
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