[Radiance-general] Annual simulation with electrochromic glass

[Zack Rogers]

Hi Julien,

You can simulate an estimate of electrochromic glass performance fairly
easily with SPOT Pro <http://www.daylightinginnovations.com/spot-home>.  It
is a work-around and performance estimate but does not have the limitations
(smearing that Rob mentioned) that a daylight cofficient approach might
have with a specular product.  You can also control the electrochromic via
an actual exterior photosensor signal or using advanced manual control
algorithms.

In SPOT to simulate electrochromic glazing, you just apply a "multiplier"
glazing as the window treatment.  Your base window might have the ~58%
transmittance of a clear state.  Then, say, the most tinted state is ~1%,
you can define a 1.7% transmittance glass and apply as the window
treatment.  This is not the most accurate way to model in Radiance as it
introduces another uneccesary surface and reflectance interactions but
should work well enough for annual space performance analysis.  This only
models the top and bottom tint state, but I think it comes pretty close to
simulating annual performance as I am not sure how often in between states
are even used.  As a designer or an occupant, I would want to have the
darkest tint if I was under direct sunlight and the clearest tint
otherwise.  They exist, but there are limited hours where there is no
direct sunlight but the clouds/sky are just too bright.  SPOT would not
capture these 2nd and 3rd state conditions.

A more accurate generic electrochromic model is in the works and will be
included in an upcoming SPOT release.

Cheers,
Zack

On Wed, Jul 6, 2016 at 4:03 AM, Julien Boutillier <boutillier at estia.ch>
wrote:

> Hi,
>
> I would like to achieve annual simulation of an electrochromic glass (tint
> change) with Radiance to obtain room illumination.
>
> I am interested in the 3 phases method, but the glass xml file defines a
> constant behavior for each hour of the year.
>
> Is it possible to create a file containing the evolutionary behavior of
> glass every hour?
> Or is there another way to simulate this kind of glass (other than one
> simulation per hour)?
>
> Thanks in advance,
> Best regards,
>
> Julien
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-- 
Zack Rogers, P.E., LEED AP BD+C
Daylighting Innovations, LLC
808 S. Public Road, Suite 200
Lafayette, CO 80026
(303)946-2310


www.daylightinginnovations.com
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