[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [TRNSYS-users] External shading during the night

Dear Marion,

Thank you for this explanation.
Given this, and in order to take into account the sky obstruction during the night by the shading devices, Tsky should probably be replaced by the external temperature when the shading devices are shut, since the shading devices temperature approximately matches with the external temperature. In that case, radiative transfer doesn't occur any more between the window and the sky. With this system, I've reached a 10% decrease in heat needs, for a low consumption building. 
Do you share this point of view?

Thanks for your help,

===========================
David Chénier
ENERTECH
F-26160 FELINES SUR RIMANDOULE
tel-fax : 04 75 90 18 54
Email : sidler@club-internet.fr
Web  : http://sidler.club.fr
================================

At 11:37 05/06/2007, you wrote:

Dear David,

The external shading device doesn't have an impact on the radiative transfer
between the sky and the windows unless you define an additional resistance.
The external shading acts as a thermal resistance and without define its properties 
It can't be taken into account by the window model of TYPE 56.


Best regards,

Marion


-----Ursprüngliche Nachricht-----
Von: Enertech [mailto:sidler@club-internet.fr]
Gesendet: Montag, 4. Juni 2007 15:23
An: TRNSYS-users@engr.wisc.edu
Betreff: [TRNSYS-users] External shading during the night


Dear Trnsys Users,

I'm using an external shading device (in the .bui file) during the nights
of winter, without additional resistance, in order to evaluate the effect
of radiative transfer between the sky and the windows during the night.

It turns out that, in my simulations, external shadings have no effect. I
obtain the same value of heat needs with or without external shadings
during the night.

However, manual calculations with radiation transfer equation tend to
acknoledge a relevant effect of using shading devices.

Could you help me with this issue ?

Thanks in advance,
Kind regards,


===========================
David Chénier
ENERTECH
F-26160 FELINES SUR RIMANDOULE
tel-fax : 04 75 90 18 54
Email : sidler@club-internet.fr
Web  : http://sidler.club.fr
================================



_______________________________________________
TRNSYS-users mailing list
TRNSYS-users@engr.wisc.edu https://www.cae.wisc.edu/mailman/listinfo/trnsys-users 

===========================
ENERTECH
F-26160 FELINES SUR RIMANDOULE
tel-fax : 04 75 90 18 54
Email : sidler@club-internet.fr
Web  : http://sidler.club.fr
================================