hillo: everybody
who can tell me how to model double-skin curtain wall in equest, as far as i kown that there is no choose for this in SD or DD WIZARD.has anybody has experience for this,any words will be appreciated!
thanks!
This is not something that can be modeled reasonably in eQUEST alone. One of the approaches that we?ve used was to couple a CONTAM + TRNSYS cavity model with an eQUEST model. The eQUEST portion of this needs to be dealt with in the detailed mode. If you don?t need to use eQUEST, there are various tools that can directly model DSF variants to one extent or another (i.e. TRNSYS, Energy Plus, IDA ICE, IES-VE, etc.). These are fairly complex tools and can still be limited for some of the DSF configurations out there. Perhaps clarifying your specifics would help to elicit more insightful responses.
Good luck,
Paul
Paul Erickson LEED? AP BD+C
We recently had to perform this analysis and worked with another consultant who developed a mathematical model to determine the DSF cavity temperatures throughout the year. Then we implemented the temperature schedule in a SUN SPACE in eQuest.
The downside to using the SUN SPACE is that daylighting calculation on the interior space does not work.
Not perfect, but in order to integrate into eQuest it seemed like a good solution.
I am linking a BESTFACADE paper which had a chapter titled ?Simplified approaches for the estimation of ventilation rates in double skin fa?ade constructions?
http://www.bestfacade.com/pdf/downloads/Bestfacade_WP4-Report_26_07_07.pdf
Alan Jackson, LEED AP
Alan,
That?s an interesting approach, alleviating another modeling program. I was previously a bit skeptical about some of the aspects of the SUN SPACE.
Re your point about daylighting, the path I ended up taking did allow for daylight accounting in the perimeter zone. In lieu of the SUN SPACE and temperatures, we determined hourly heat transfer (pos and neg) between the cavity and interior zones using TRNSYS. We then created an hourly load schedule to be applied to the perimeter zone in eQUEST. I had originally thought to make the perimeter wall adiabatic but decided to approximate that by creating a glass type with very high thermal resistance and SHGC of ~0. The Tvis value was still active and could thus accommodate the daylighting addition. Looking back I would go with adiabatic and do daylighting within TRNSYS so that the heat transfer from cavity to zone in TRNSYS took any electrical lighting reductions into account. A reminder that modeling never achieves perfection.
Paul
Paul Erickson LEED? AP BD+C
Paul & Alan,
Thanks for the insight.
So what I?m hearing in this conversation is that the sunspace command in DOE2 is not reliable for this ? is that correct? I am in the process of looking into this on a project and did some preliminary studies with a sunspace. I created a 2 foot sunspace that runs along the south side of my fa?ade and have it set up for a venting schedule and all of that good stuff. Is this approach not going to work?
What?s the drawbacks with the sunspace calculation in DOE2?
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Vikram Sami, LEED AP BD+C