[TRNSYS-users] Windows shading coefficients

[David Bradley]

Dear Maurizio

>1) I'm currently modelling in PREBID a residential building for which the 
>montly Shading Coefficients on the windows have been calculated with the 
>software ECOTECT. I insert the SC in the appropriate field ("external 
>shading coefficient") as an input and set the "view factor" to 0,5 
>(vertical surfaces). It's the exact way? My doubt is that the solar 
>incident radiation is halved (view factor = 0,5) and then reduced of the SC...

It is correct, provided that the shading coefficient from Ecotect is the 
opaque fraction of the window (i.e. 1 = completely shaded).
The view factor to the sky (FSky) is only used for longwave radiation so it 
will not interfere with shading.

The one thing to bear in mind about PREBID's external and internal shading 
coefficient is that the entered fraction effects both beam and diffuse 
radiation equally. Thus if you enter a value of 0.5 for the external 
shading factor, half of the incident diffuse radiation and half of the 
incident beam radiation will enter the space. If you want to treat beam and 
diffuse radiation separately, you can use one of the external shading 
models (Type34, or Type68).

>2) It's possible to use old TESS libraries with TRNSYS 16 or are they 
>already comprised in the new version?

Because of the change in coding standards for components between version 15 
and 16, the TESS Libraries v. 1.x are not directly useable with TRNSYS v 
16. We have, however, expanded the libraries and released version 2.0, 
which are not only compatible with TRNSYS 16 but are also backwards 
compatible with TRNSYS 15. If you are interested in upgrading, you will be 
credited the full amount that you paid for your version 1.x libraries 
toward the purchase of version 2.x libraries. If you do not wish to upgrade 
then you can follow the steps laid out in the TRNSYS 16 documentation that 
show you how to modify a TRNSYS 15 Type to make it accessible from TRNSYS 
16. I will send along a second email containing a document that lists the 
contents of the 12 version 2.0 libraries as well as an order form that 
contains the pricing information. I would be happy to answer any questions 
that you might have about them.

Kind regards,
   David


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Thermal Energy System Specialists (TESS), LLC
David BRADLEY                           2916 Marketplace Drive - Suite 104
Partner                                        Madison, WI 53719
Phone: (608) 274-2577 USA
Fax: (608) 278-1475
E-mail: bradley at tess-inc.com
Web Pages:  http://www.tess-inc.com     and      http://www.trnsys.com

"Providing software solutions for today's energy engineering projects"
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