[Equest-users] Adding Insulation to existing building(UNCLASSIFIED)

[Eurek, John S NWO]

Classification: UNCLASSIFIED
Caveats: NONE

On this topic, I believe the increase in cooling energy will not happen if
you have an economizer. Theory:  The insulation keeps the outside temperature
outside.  When the economizer run, it will bring the outside temperature
inside, in effect negating the insulation.  (Artificially lowering the R
value)  So the cooling load should not increase with an economizer.

Am I missing something in my logic?

I have ran some models and the cooling load still went up even though I had
an economizer.

I use Trace so I don't know if e-quest does a better job on this, but in
theory super-insulating shouldn't be a problem if an economizer is present.

One thing that might be happening is that the economizer runs if the certain
conditions allow, but the program does not look at the tradeoff between fan
energy and compressor energy.  If the outside air is 58 degrees the
economizer will run and the fan will have to run a lot, but it might take
less energy to run the compressor and the fan would run less.



This leads into a common discussion in my office.  If it is more efficient to
produce colder chilled water and reduce the chilled water pump speed, or vary
chilled water temp and keep the chilled water pump speed steady?  It is a
multi-variable complex problem.  At the level of determining if it is more
efficient to reduce fans, compressors or pumps I think the modeling software
does not have the resolution.  If the piping was installed with too many
bends, it may be better to reduce the pump speed. If the compressor was
manufactured just a little out of tolerance it may be better to reduce the
fluid temperature.  I don't want to say it is splitting hairs, but it is
getting close.

What is really needed is a smart system that can every try different things
(lowering water temp vs lowering fan speed) and determine which uses less
energy for that building.  (but then I fear the buildings would learn too
much and when I adjust the thermostat; H.A.L would say "I'm sorry Dave, I can
not allow you to do that."


-----Original Message-----
From: Nick Caton [mailto:ncaton at smithboucher.com] 
Sent: Wednesday, September 07, 2011 3:00 PM
To: Eurek, John S NWO; mikef at facilitymgt.com;
equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] Adding Insulation to existing
building(UNCLASSIFIED)

Agreeing with John per usual... 

Any building with internal loads will have some break-point where adding
more insulation to the envelope will be detrimental to annual energy
consumption.  It's a bigger deal whenever your internals are relatively
high.  The behavior you're describing is fundamentally sound.

A good thermos keeps my coffee hot longer (great in the wintertime), but
it's not the ideal container when my coffee is scalding-hot and I want
the contents to cool down.  

I've yet to settle on a favorite analogy myself... this just comes to
mind because I need to make a new pot here at work...

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 


-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Eurek,
John S NWO
Sent: Wednesday, September 07, 2011 2:53 PM
To: mikef at facilitymgt.com; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Adding Insulation to existing
building(UNCLASSIFIED)

Classification: UNCLASSIFIED
Caveats: NONE

The results may be accurate, I have found that over insulating can cause
the
cooling load to increase if there are internal loads.

Same way you can get over heated in the winter if you are scooping snow.
Losing energy thru the wall isn't always bad.

-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of
mikef at facilitymgt.com
Sent: Wednesday, September 07, 2011 2:48 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Adding Insulation to existing building

I have an existing 360' X 140' metal building with offices at one end.
They
have the standard 4" thick insulation trapped between girts and panels.
In my
building simulation eQuest got within 5% of actual utility bills, but
when I
started adding insulation the model gas heating bill went down and the
electric cooling bill went up. Any ideas what I am doing wrong?
Thanks 
 
Mike Freeman PE.
Facility Management & Engineering, Inc.

Classification: UNCLASSIFIED
Caveats: NONE


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