[Equest-users] FW: Solar panels

Mon Nov 8 11:41:49 PST 2010

It has been awhile since my last PV studies (they were for fixed units,
not tracking), but I did manage to account for everything within
eQuest... maybe what I can recall will help:

Specific to the "how" to account for PV arrays' effects on a roof or
other building surface's envelope loads, you really can learn it all by
just exploring the required inputs in detailed mode.  Create a 'dummy'
PV module with made up values under the utility tab, then create an
electric generator of the type photovoltaic array.  When you do this you
can explore all the variables regarding how they're mounted
(coverage/standoff/surface/tilted/etc).  In doing so you can select the
roof surface which is being shaded.  Parametric runs for each variable
can help you find a "sweet spot" specific to your site for each of those
variables.

Alternatively, I just popped in and it looks like you could also define
all the geometries by first making building shades of the appropriate
geometry/orientation/etc. and then assigning those within the electric
generator window tabs.... Seems like extra work but then you could have
them in your 3D view if that matters to you.

Alan's right to think of them first as a shade, but fixed panels can be
a little trickier when it comes to the building envelope loads.  I can't
speak for other programs (and I don't doubt there are simpler options
from a UI perspective), but I know eQuest does go so far as to account
for the degree of convection between your roof surface and panels
(working from weather data wind speed) and the rate of transfer through
the panels, beyond just accounting for direct solar loads.  For any
faults with complexity it does seem to do a sophisticated job of
modeling PV generation.  

On a related note, I'd be somewhat surprised if any alternative programs
don't allow you to define properties of the inverter equipment... those
losses can be a pretty big deal for any ROI study, iirc.  In any case,
Peter's suggestion to use an outside program to work out the power
generation is not something I disagree with, but I just wanted to be
suggest if you go that route to consider what's possible within eQuest
to accurately account for the arrays' envelope effects. 

~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 Peter
Hillermann
Sent: Monday, November 08, 2010 11:33 AM
To: alanc at dwcei.com; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] FW: Solar panels

Alan,

You got me off on a tangent because I do love solar panels. Remember
that your panels are connected in series and that if one gets shaded
your entire row goes out, unless you are using micro inverters. You
really need to do a shading study and if you use REVIT this can be done
easily. When using a PV panel as a canopy or shading device you need to
watch the summer time shading on your wall. Typically a long shadow on
the wall by parapet or cornice might shade the panel, which is created
by the noon day sun. Just push the panel a little further off the wall.

Best of luck to you and I hope it all works out.

PETER HILLERMANN

peterh at westallarchitects.com

westall

architects

3404 pierce drive

chamblee, georgia 30341

o 770.458.4113

f  770.458.5352

c 678.898.2936

westallarchitects.com

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Alan
Crittendon
Sent: Monday, November 08, 2010 11:12 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] FW: Solar panels

Is there a way to put power generation into equest?  I was really just
thinking about the shade portion but this would be great too!

Alan Crittendon, PE, LEED AP
DW Collier Engineering, Inc.

________________________________

From: Peter Hillermann [mailto:peterh at westallarchitects.com] 
Sent: Monday, November 08, 2010 9:59 AM
To: alanc at dwcei.com; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] Solar panels

Alan,

To be honest there really is no good way to model the solar panels. PV
watts is really good because it calculates panels all over the state
using averages. It also depends on what system you are using. If you use
a roof mount system that has a specific tilt you get a certain
efficiency. If you use a system has trackers it becomes more efficient
but the price might go up. Different states have different tilt angles
to make their panels more efficient with the better degree of tilt. The
thing I would do if you wanted to put it in eQuest is use PV watts
calculator and apply it as a direct load that gives electricity to the
building.

PS: check to see what inverter you are using because different inverters
have different efficiencies.

PETER HILLERMANN

peterh at westallarchitects.com

westall

architects

3404 pierce drive

chamblee, georgia 30341

o 770.458.4113

f  770.458.5352

c 678.898.2936

westallarchitects.com

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Alan
Crittendon
Sent: Monday, November 08, 2010 8:43 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Solar panels

I need to have about 5000ft of roof space dedicated to solar panels on a
41000ft roof.  How can I model 5000ft of roof to be 100% reflective?

Alan Crittendon, PE, LEED AP
DW Collier Engineering, Inc.

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