[Equest-users] Double Exterior Facade Modeling

[Kasun, Darryl]

Chetan,

Your approach sounds good to me.  Hopefully you'll get more feedback.

I read your post and this is similar to a model I am trying to build in eQuest.  I'll give you a quick description of what I am trying to do. 

An existing building currently has three options for a building envelope upgrade.  One of these options is to build a curtain wall aprox. 2-3ft out from the existing exterior wall.  The wall to window ratio for the existing exterior wall and new curtain wall is approx. 0.2 and 0.8, respectively.  So far I've changed the existing exterior wall into an interior wall and added the curtain wall (exterior wall) about 2 ft out.  Basically there a three combos of facades that heat will transfer through.  New glazing, air gap, existing glazing.  New glazing, air gap, existing wall.  New wall, air gap, existing wall.  Do you know if eQuest will model the heat transfer through these two facades accurately?  

-----Original Message-----
From: Chetan [mailto:kce3 at kamalcogentenergy.com] 
Sent: May-14-11 7:28 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Double Exterior Facade Modeling

Hi All,

We are working on an office building project in which there are two façade
i.e. exterior and interior façade. Between these two there is an air gap
with intelligent buffer on top which can be opened and closed. As to get the
effective U value of the wall we have to consider the air gap and exterior
façade also. During summer the intelligent buffer remain open which cause
air flow in the gap hence at that time the heat transfer rate will be more
and during winter the intelligent buffer will be closed which causes no air
flow in the gap hence at that time the heat transfer will be less. As in
both conditions the effective U value will vary.
This is a LEED model where currently our thought is to make one model (with
buffer open) for summer season and another model with buffer closed for
winter season. But only one ASHRAE baseline model. Is this the best approach
or is there a better one?

Regards
Chetan Bhoj