[TRNSYS-users] Trnsys17

[Chiara Colucci]

Thank you very much.

Kind regard
Chiara

2016-05-02 11:30 GMT+02:00 hotline <hotline at transsolar.com>:

> Dear Chiara,
>
> yes you are right. Use HTC =  0.01 kJ/k m² (not a smaller value!!!) for
> inside and outside to make the virtual window surface temperature approach T
> sky.
>
>
>
> Best
> Jakob Merk
>
>
>
>
> _________________________________________________________________________________________________
>
>
>
> *Jakob Me**rk*
>
> TRNSYS Software Team
>
>
> *Transsolar Energietechnik GmbH*
>
> Curiestraße 2
>
> 70563 Stuttgart
>
> Fax:        +49 711 67976-11
> Email:    hotline at transsolar.com
>
> Web:      www.trnsys.de
>
>
>
>
>
>
>
> *Von:* TRNSYS-users [mailto:trnsys-users-bounces at lists.onebuilding.org] *Im
> Auftrag von *Chiara Colucci
> *Gesendet:* Donnerstag, 28. April 2016 12:16
> *An:* TRNSYS users mailing list at OneBuilding.org
> *Betreff:* Re: [TRNSYS-users] Trnsys17
>
>
>
> Hi Jakob, thank you for the reply. I think I will use the solution 1.
> About this I would like to know why you talk only* inside HTC*. Also *outside
> HTC* has to be small?
>
> Best regard
> Chiara
>
>
>
> 2016-04-22 13:12 GMT+02:00 hotline <hotline at transsolar.com>:
>
> Dear Chiara,
>
>
>
> A virtual surface isn’t the appropriate approach.
>
> Virtual surfaces should be used  as adjacent surfaces between zones in
> SketchUp which are merged into one zone with multiple airnodes.
>
>
>
> A virtual surface isn’t a heat transfer surface, it doesn’t exist in the
> thermal model. Thus, the error
>
> message is correct. The volume of the canyon zone  isn’t closed and
> therefore no view factor matrix
>
> could be calculated.
>
>
>
> Modelling outdoor space isn’t  a straightforward task.
>
>
>
> Solution 1
>
> In order to generate a closed volume of the canyon and allow solar
> radiation to penetrate into the zone
>
> you need a window. To do the shortwave solar correct you may use a
> so-called “no window” which has a transparency of 100 %.
>
>
>
> However, this surface has a temperature and thereby influences the zone
> air temperature by its inside convections
>
> heat transfer coefficient (HTC) and the longwave exchange by its
> temperature.
>
>
>
> For reducing the influence on the air temperature you may define the
>  inside HTC to be small (like 0.01 kJ/k m²).
>
> For longwave radiation exchange the window temperature should be
> approximately the sky temperature.
>
> However, you can’t fix a temperature of window. You have to try to
> calculate a surface gain such that the
>
> Temperature is close and the model is still converging.
>
>
>
> Solution 2
>
> You use solution 1 for calculating the incident radiation (total and
> direct) on the window and use this radiation
>
> as input to a model which doesn’t contain a “canyon zone”.  For longwave
> radiation exchange you have to
>
> estimate the “effective ground temperature”.
>
>
>
>
>
> All the best
>
> The Transsolar Software Team
>
>
>
>
> _________________________________________________________________________________________________
>
>
>
> *Jakob Merk*
>
> TRNSYS Software Team
>
>
> *Transsolar Energietechnik GmbH*
>
> Curiestraße 2
>
> 70563 Stuttgart
>
> Fax:        +49 711 67976-11
> Email:    hotline at transsolar.com
>
> Web:      www.trnsys.de
>
>
>
>
>
>
>
> *Von:* TRNSYS-users [mailto:trnsys-users-bounces at lists.onebuilding.org] *Im
> Auftrag von *Chiara Colucci
> *Gesendet:* Mittwoch, 6. April 2016 16:49
> *An:* trnsys-users at lists.onebuilding.org
> *Betreff:* [TRNSYS-users] Trnsys17
>
>
>
>
>
>
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