[Bldg-sim] Frequently used door

[Nick Caton]

Hi John!

 

I think the short answer is bump up your ACH for the room "higher than
normal."  Trying to quantify any more specifically is probably a
fruitless endeavor - way too many variables in play...

 

Fundamentals 2009 has a fuzzy thing or two to say about to what extent
door infiltration ordinarily affects whole-building infiltration
(6-22%):

 

Windows and doors (6 to 22%; 15%). More variation in window

leakage is seen among window types (e.g., casement versus

double-hung) than among new windows of the same type from different

manufacturers (Weidt et al. 1979). Windows that seal by

compressing the weather strip (casements, awnings) show significantly

lower leakage than windows with sliding seals.

 

That may help you establish a ceiling to what's likely.

 

There's also a longer discussion relating that "rough" ACH estimations
have to be made in design for the purposes of sizing HVAC equipment on
(page 16.29)... Examples provided for some smallish (80-150SF)
vestibules range from 0.5 to 2.0 ACH, but importantly illustrate the
process is necessarily somewhat arbitrary.  The point they're making is
there are a bunch of hard to measure/estimate variables in play to
determine actual ACH, from height to hourly temperature differentials to
wind pressures.  

 

Throw a "higher" number at it, at least until someone can source/share
some table of "better guesses" =). 

 

~Nick

 

 

NICK CATON, P.E.

SENIOR ENGINEER

 

Smith & Boucher Engineers

25501 west valley parkway, suite 200

olathe, ks 66061

direct 913.344.0036

fax 913.345.0617

www.smithboucher.com 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of John Eurek
Sent: Wednesday, August 24, 2011 2:06 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Frequently used door

 

I'm trying to model a small building (600 square ft) which will be used
to inspect cars.  The worker will frequently be using the door.  Logic
would say that the equipment sizing and design would be different from a
similar building with a door which is not frequently used.

 

The building is so small that leaving the door open for a short time
could result in a complete air change in a short time.

 

I use Trace 700.  Does anybody have any methods to account for high door
usage to size the equipment?  Trying to make up an energy model will be
difficult also.

 

 

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