[EnergyPlus_Support] DOAS is good... is bad

["Jean marais" <jeannieboef@xxxxxxxxx>]

Hi all, we started a discussion a while ago on the pros and cons of radiant ceiling systems. I just by chance came across a wikipedia (sorry about the reference) round up on the authors take on DOAS.

http://en.wikipedia.org/wiki/Dedicated_outdoor_air_system

I've also read some ASHRAE journal on the topic, but I'll have to do some fishing to find the articles again. This topic is actual for me and all others in Europe. I have questions:

1) When modelling chilled ceilings in eplus (not chilled beam induction or forced air units), I currently construct a construction for the ceiling with slab, insulation, Aluminium sheet 1mm, internal source, Aluminium sheet 1mm. As the panals are in reality just pipes strapped to a porous metal sheet that hangs like suspended ceiling, should I still build in a Air gap in my construction above? 

2)Is this the best approach? Should I do something to mimic the porosity of the sheet?

3) Most air supply diffusers are designed to "stroke" the ceiling with supply air to maximize the convection transfer. Is it worth modelling with advanced convection coefficients on these surfaces?

4) Unlike a heated floor where the pipes are really asphalted in, these panels represent a separate zone equipment, like a fan coil. I find the current way that I model these very tedious. Is there any word on a future object, like the chilled beams object to make this more user friendly?

5) Would using the chilled beams object be a better, more accurate work around and how would I set it up.

...And last but not least...(especially Dr. Li)...what do you think are the advantages / disadvantages of DOAS?



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