[esp-r] Re: Suggestions for Double Facade Modeling

[Jon Hand]

The original description noted a cavity on all sides of the building.  Can you describe the design idea
which supports a double skin on the North face of the building?  Is it the same kind of 
facade as on the South face?  Consider that the timings of the solar exposure on each of the
facades is radically different.  A North double skin might have much different economics to
the other facades, it might have rather different characteristics and the building might work
better without the North skin.

It requires only a few changes in the source code to move from 82 zones to something like 99
zones (lets avoid going to 3 digits in the zone numbering because some of the reporting
and file I/O might assume only 2 digits.  

A cautious approach would be to model a portion of the building and the facade
so that you can learn quickly about how zone descriptions and flow networks are
designed and can test and learn prior to scaling up the model.  To get a
4-6 level model working kills fewer brain cells than attempting a seriously
complex model.

-Jon Hand
________________________________________

From: esp-r-bounces at lists.strath.ac.uk [mailto:esp-r-bounces at lists.strath.ac.uk] On Behalf Of Geissler Achim
Sent: 21 June 2012 10:58
To: esp-r at lists.strath.ac.uk
Subject: [esp-r] Re: Suggestions for Double Facade Modeling

Dear Ömer

basically, you will want to model the facade cavity as a set of stacked zones. Also, you will probably want to have more than one zone in the width (ideally in the depth, as well, to allow for different directions of flow along the inner and outer skin of the facade cavity. If the corners of the building are also open, as it seems to be, it may be interesting to really have a set of zones enveloping a central "building". The standard maximum number of zone is 82, so this may be a limit.

For the stack, you could split the height of the building into maybe 4 to 10 segments, for the width per façade 2 segments. This would give you 32 to 80 zones (so 10 in the stack would already be close to the limit) without a split in the depth. With a split in the depth, a stack of 4 would lead to a total of 64 zones. The actual building could be "a few zones", however, then be aware that the detail of results is also very limited and you will need to add appropriate thermal mass and internal loads.

If you expect cross-flow and "around the corner flow" in the façade cavity to be negligible, of course looking at one façade elevation only would greatly reduce the number of zones or allow for higher detailing of zones. You could turn the model via script for calculations in all directions.

The "best" approach will strongly depend on the most important issues to be studied.

Best
Achim




Von: esp-r-bounces at lists.strath.ac.uk<mailto:esp-r-bounces at lists.strath.ac.uk> [mailto:esp-r-bounces at lists.strath.ac.uk]<mailto:[mailto:esp-r-bounces at lists.strath.ac.uk]> Im Auftrag von Ömer Moltay
Gesendet: Mittwoch, 20. Juni 2012 22:05
An: esp-r at lists.strath.ac.uk<mailto:esp-r at lists.strath.ac.uk>
Betreff: [esp-r] Suggestions for Double Facade Modeling

Dear esp-r Users,

We would like to simulate a 43 storey high office building (located in a Mediterrenean climate) with double facade for energy calculation purposes. The double facade is a single cavity on all four sides of the building and from first floor to the top floor.  The depth of the cavity ranges between 3 - 5 meters. The design intent is to ventilate it via thermal buoyancy and also operable windows on the exterior skin (automatic control). No natural ventilation of the office interiors or night time cooling is foreseen at the moment. We would like to analyse the best ways of design and operation and see how much we can decrease the HVAC cooling / heating running costs.

We intend to use esp-r and DOE/eQuest for this. I would appreciate any suggestions on how to approach this task.

Thank you,

Ömer Moltay, LEED AP BD+C, ASHRAE BEMP, CPMP, BREEAM Assessor
Mimta EkoYapi
Hekimsuyu Cad. 559. Sk. No:39
34255 Kucukkoy Istanbul Turkey
Tel: 90-212-617-2296
Fax: 90-212-617-2297
www.eko-yapi.net<http://www.eko-yapi.net/>