[TRNSYS-users] Trnsys17

[Chiara Colucci]

Hi Jakob,
if I use HTC =  0.01 kJ/k m²  for inside and outside, TRNSYS give me this
error you can see in the attached.

Thank you in advance

Kind regard
Chiara

2016-05-02 11:49 GMT+02:00 Chiara Colucci <chiara.colucci175 at gmail.com>:

> 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
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> TRNSYS-users mailing list
>> TRNSYS-users at lists.onebuilding.org
>> http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org
>>
>>
>>
>> _______________________________________________
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>>
>>
>
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