[Equest-users] Roof gardens

[Nick Caton]

Additional food-for-thought...

 

Something to model which may improve the modeled performance of this
roof:  You might want to create a series of building shades
immediately/shortly above and parallel to your roof surface(s) to
roughly match the coverage of the actual garden plants and assign them a
shade schedule (transmittance through the year) to match their foliage
patterns.

 

If this garden provides shading in the summer and allow direct sun loads
in the winter, it may help your heating/cooling loads in a good way both
seasons.

 

That said, coming up with a way to account for the variable thermal
properties of moist/dry soil as Dakota brought up is something I'd be
more concerned about.  I'd like to hear what others may have done to
address that issue.  A good place to start might be to create your
custom construction layers/materials based on "damp" (not dry or
saturated - a happy medium) soil conditions.

 

~Nick

 

 

 

NICK CATON, E.I.T.

PROJECT ENGINEER

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

Check out our new web-site @ www.smithboucher.com 

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Dakota
Kelley
Sent: Tuesday, April 27, 2010 2:28 PM
To: Stephen Sorensen; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Roof gardens

 

There are a wide variety of construction types for green roofs, so
you'll have to create a custom construction (probably using custom
materials) for the roof as-designed.  The problem is that the roof's
thermal properties are not constant; e.g. the soil/growing medium's
conductivity depends on moisture content, among other things.  eQUEST
does not handle variable material properties, so you'll have to be
comfortable with the inaccuracy.  Also, if the resulting construction is
too thick, roughly three feet or more, eQUEST will give you an error
message.  

 

Dakota Kelley

Telios MEP Engineers

 

________________________________

From: Stephen Sorensen [mailto:ssorensen80 at gmail.com]
Sent: Tue 4/27/2010 1:44 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Roof gardens

Hi everyone,

 

Is anyone familiar with R-value calculations for a roof top garden or
how one would model this in e-quest.

 

Stephen Sorensen

Hansen Engineering

Friendsville, PA

P: 570-553-4284

F: 570-553-0234

 

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