[esp-r] Re: Calculation of solar gains through complex shading devices

[Germán Molina Larrain]

Hi Achim,

my original idea of workflow was thought on the basis of a straightforward
finide difference simulation (as I have done in Matlab)... so it would be
to make the solar simulations (calculation of solar gains and Daylight),
and then, to make the thermal simulation; knowing the flows to each node
(calculated before).

Now, since you say that ESPr supports BSDF input, maybe the whole thermal
simulation should be done in ESPr, leaving Radiance just for lighting. I
have been working on the generation of the BSDFs, and I think the problem
is practically solved right now, using tools that already exist (I expect I
can publish something related to this). How long do those (BSDFed)
simulations take? I have heard that in E+ they take considerably more time
than the other ones.

As far as I am aware, the three-phase-method and the "coupling" with
EnergyPlus requires two runs? Could you describe the necessary workflow /
calculation steps? Where / in which program is the setting of a Venetian
type blind set, for example? Based on what?

The direct coupling, I was informed, is complicated. But, just as in ESPr,
E+ was provided with the capability of using BSDF information in a very
similar way as the Three-phase method does. So everything is actually made
on E+.


Anyway, I guess the best should be to make the lighting simulation,
calculate the electric lighting consumption and transform it into internal
gains for a posterior ESPr simulation, considering BSDFs? Please feel free
to comment.

THANKS VERY MUCH

German


2013/5/7 Geissler Achim <achim.geissler at fhnw.ch>

>  Dear German****
>
> ** **
>
> basically, that is a very interesting idea. However, I would not expect
> this to be easy and straightforward, as one strength of ESP-r is that it
> solves all the physics simultaneously. Currently, there are two possible
> ways to include complex shading: The "CFC" model for multi-layer
> constructions (to date, this covers venetian type blinds, roller blinds and
> meshes are "in the works" as far as I am aware) and the input of
> bi-directional reflection / transmission input data ("BRTD") - here the
> problem is basically generating the necessary input data, however this may
> be possible via Window 7 (LBNL), now.****
>
> ** **
>
> ESP-r can basically take the solar distribution on the surfaces of the
> zone behind the window into account. In the mainstream code, the CFCs lack
> daylighting, however. I am not sure what the situation in this regard for
> the "BRTD"-type of models is.****
>
> ** **
>
> As far as I am aware, the three-phase-method and the "coupling" with
> EnergyPlus requires two runs? Could you describe the necessary workflow /
> calculation steps? Where / in which program is the setting of a Venetian
> type blind set, for example? Based on what?****
>
> ** **
>
> Best****
>
> Achim****
>
> ** **
>
> ** **
>
> ** **
>
> *Von:* esp-r-bounces at lists.strath.ac.uk [mailto:
> esp-r-bounces at lists.strath.ac.uk] *Im Auftrag von *Germán Molina Larrain
> *Gesendet:* Dienstag, 7. Mai 2013 01:07
> *An:* esp-r at lists.strath.ac.uk
> *Betreff:* [esp-r] Calculation of solar gains through complex shading
> devices****
>
> ** **
>
> Hello, ****
>
> ** **
>
> I am German Molina, and I am doing my MSc. on complex shading systems, and
> how to treat them for simulation purposes (Lighting and Solar Heat Gains).
> I do not really use ESPr or any other thermal simulation tools, just
> Radiance for now.****
>
> ** **
>
> Finished my literature review, I realized that one method used for
> lighting (the Three-phase method) might be good to be a good estimator of
> the Solar Heat Gains through complex fenestration systems... later I found
> out that some people did this, and actually nowadays something very similar
> can be implemented in EnergyPlus.****
>
> ** **
>
> Long story short, I think (it is waiting for a validation) that I can
> accurately calculate the Solar Heat Gains through virtually any complex
> fenestration system of known BSDF matrices; and not only net solar heat
> gains, but I think I can also say where the solar radiation is going
> (calculate the fraction that goes to the ceiling, to the floor, etc.). How
> difficult would it be to use this output as an input for ESPr? For what I
> understand, ESPr does not handle very well these kind of systems?****
>
> ** **
>
> What I am proposing can be actually reduced to just one phrase: Lets use
> Radiance to what it does best (radiation transport) and ESPr to what I
> think it does best (Thermal simulation).****
>
> ** **
>
> THANKS VERY MUCH****
>
> ** **
>
> German Molina****
>
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