[esp-r] Re: Proposed development of window shading models

[Bart Lomanowski]

Hi Achim,

To answer some of your quesions... 

> - Lumping the Blind: Input data would still be slat properties and geometry?
> ESP-r would internally calculate the "lumped properties" on a time-step basis
> (provided somebody involves control for such blinds - angle, percentage of
> lowering etc.)?

Yes, the first step is to provide slat angle input during the construction 
stage, but this can be changed at each time step in a control strategy. The 
lumped or system optical properties are internally calculated on a time-step 
basis.   

> - Could lumping an internal (or façade gap zone) blind allow this blind to
> "hang" freely in a CFD-Zone (e.g. for "extract mechanical" type of façade)?

This is a good question. As I mentioned in the presentation, the interior 
venetian blind convection models are fairly crude at the moment. The complexity 
of adding a free hanging blind is not part of the scope of the work. The indoor 
blind will be treated as an interior surface or a construction.  

> - Is the current limitation of beam radiation tracking through one TMC only
> generally being addressed by your work? That would surely be a huge benefit
> to the program as a whole (offices with windows to atria etc.). Or is such a
> setup you describe a new kind of TMC - i.e. one surface for ESP-r?

That aspect is not being considered. As a starting point, the intent is to 
enhance the current treatment of TMCs. Of course there are many other 
enhancements that would be beneficial, but as a master's student, I have to 
limit the scope to some extent. 

> - Are blinds in a ventilated gap (buoyant and / or forced, connected to an
> air flow model) possible?

Good point. I will investigate this possibility further as I have limited 
knowledge on airflow connections in ESP-r. 

> - Would vertical Venetian blinds be possible?

Yes, this is possible. The angular dependence is simply switched from the 
profile angle to the azimuth angle for this case. However, we have not 
investigated convection models for vertical slat blinds, so simplified models 
will have to do for now. 

> - Are you using spectral data? Or a reduced "overall" set for solar and
> visible light, each?

Not using spectral data. Total or "overall" properties are used. 

> - What you mention on "available output" e.g. U-value and SHGC is very
> important IMO if one enters the individual layers of a system. This would
> enable checking against Window 6.0 or WIS for model quality control! Such
> output should also include visible light transmission (and maybe more), IMO.

The U-value and SHGC values can be calculated quite easily from the results of 
the multi-layer solar-optical model and the complex resistance network. These 
indices will definitely be made available for documentation/validation 
purposes.   

Thanks for your thoughts,

Bart