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On one project the reviewer demanded that I increase the plug load cost
from 23.5% to 25%. In my experience, the reviewer always looks for
this one as it is an easy one to point to so the reviewer looks like
he/she is doing their job.<br><br>
At 06:12 PM 4/30/2010, Carol Gardner wrote:<br><br>
<br>
<blockquote type=cite class=cite cite="">---------- Forwarded message
----------<br>
From: <b>Carol Gardner</b>
<<a href="mailto:cmg750@gmail.com">cmg750@gmail.com</a>><br>
Date: Fri, Apr 30, 2010 at 2:40 PM<br>
Subject: Re: [Bldg-rate] LEED+90.1 Process/Plug Loads Conundrum<br>
To: James Hess
<<a href="mailto:JHess@tmecorp.com">JHess@tmecorp.com</a>>, Nick
Caton
<<a href="mailto:ncaton@smithboucher.com">ncaton@smithboucher.com</a>
>, Karen Walkerman
<<a href="mailto:kwalkerman@gmail.com">kwalkerman@gmail.com</a>><br>
Cc:
"<a href="mailto:bldg-rate@lists.onebuilding.org">
bldg-rate@lists.onebuilding.org</a>"
<<a href="mailto:bldg-rate@lists.onebuilding.org">
bldg-rate@lists.onebuilding.org</a>><br><br>
<br>
Hi Nick,<br><br>
I'm glad you raised this issue. <br><br>
First, I agree with James, and have heard from other people, that LEED
accepts documentation saying something as basic as "hey, I don't
have 25% plug loads".<br><br>
Second, when you have to create a baseline to measure up from, you are
forced to say what that baseline is. For instance, in 1985-86, working on
the BPA-funded Energy Edge project, we had to figure out the baseline for
a group of buildings being designed to exceed the current energy codes by
30%. We didn't have a baseline then. To deal with this we assembled a
group of people that we euphemistically called The Greybeards (so sorry
to you all). The tables now known as G3.1.1A & G3.1.1B in Standard 90
came out of what we created in that moment of time. We were trying to
limit what is called "gaming the system"<br><br>
So now it seems it has been deemed important to control the baseline a
little more: by specifying plug loads at 25%. The goal of trying to limit
gaming the system might be the source of the 25%. The danger which Nick
has clearly demonstrated in his email is that what is meant to control
gaming the system, may now actually be creating it.<br><br>
Further thoughts/comments welcome,<br>
<font color="#888888"><br>
Carol<br><br>
</font>On Fri, Apr 30, 2010 at 1:42 PM, James Hess
<<a href="mailto:JHess@tmecorp.com">JHess@tmecorp.com</a>>
wrote:<br>
<dl><br>
<dd>This is a good question. On prior projects we have worked on, I
have found that you can have less than 25% plug loads, so long as you
have some documentation to back it up.<br><br>
<dd> <br><br>
<dd>For example, we are currently working on a prison project. The
plug loads are very low for obvious reasons; they don’t provide stereos,
computers, ipods, TV’s, etc. to the inmates (typically, all they get is
an alarm clock/radio that uses ~ < 10 watts). There is no way on
this project that we could get the plug loads to come in at 25% unless we
artificially jacked them up to levels that would never exist in
reality. We would have a similar problem in that the Proposed
Design equipment would not be able to cool the spaces. So, we just
document the loads we do have and I believe we are good. The
project has been through the 1st</sup> review and this has not come up as
an issue. <br><br>
<dd> <br><br>
<dd>I believe we have had other projects where we documented the loads we
had and passed the review with no problems. We will typically
develop a simple spreadsheet and document the internal loads that each
room has. That is easy enough to do these days I believe, for most
applications. For example, a typical desktop computer uses about 65
watts on average, monitor = ~ 45 watts (depending on size), clock radio ~
10 to 15 watts, etc. you get the point. (get a “Killawatt” power
meter from Amazon and have some fun taking some measurements to see
approximately how much power stuff uses, guaranteed to provide hours of
fun).<br><br>
<dd> <br><br>
<dd>Just provide some documentation on some good reasonable estimates for
the loads and I think you will be fine.<br><br>
<dd> <br><br>
<dd>An alternate method is to use default values from Table G-B from the
ASHRAE 90.1-2007 Users Manual.<br><br>
<dd> <br><br>
<dd>For example, the Receptacle Power Density for the Office Building
Type is 0.75 watts/SF per Table G-5.<br><br>
<dd> <br><br>
<dd>If using that value results in the process loads being less than 25%,
my comment to the reviewers would be that the 0.75 watts/SF is the value
determined by ASHRAE to be appropriate for the building type.<br><br>
<dd> <br><br>
<dd>I think the most important thing is to use something reasonable and
defendable, and make it the same between the Baseline and Proposed Design
energy models. Our experience indicates that it does not have to be
exactly 25%, can be less than 25% or greater than 25%, depending on the
building.<br><br>
<dd> <br><br>
<dd>One thing that is interesting is that on federal projects, per EPACT
requirements, you do not have to factor in the process/recep loads for
the purpose of determining whether the 30% savings requirement has been
met. That makes it easier to show 30% savings. <br><br>
<dd> <br><br>
<dd>Thanks!<br><br>
<dd> <br><br>
<dd>Regards,<br><br>
<dd> <br><br>
<dd>JAH<br><br>
<dd> <br>
</b><br>
<dd>James A. Hess, PE, CEM<br>
</i></b><br>
<dd>Senior Energy Engineer<br><br>
<dd>TME, Inc.<br><br>
<dd>Little Rock, AR<br><br>
<dd>Mobile: 501-351-4667<br><br>
<dd> <br><br>
<dd> <br><br>
<dd> <br><br>
<dd> <br><br>
<dd>From:</b>
<a href="mailto:bldg-rate-bounces@lists.onebuilding.org">
bldg-rate-bounces@lists.onebuilding.org</a>
[<a href="mailto:bldg-rate-bounces@lists.onebuilding.org" eudora="autourl">
mailto:bldg-rate-bounces@lists.onebuilding.org</a>] On Behalf Of </b>Nick
Caton<br>
<dd>Sent:</b> Friday, April 30, 2010 12:55 PM<br><br>
<dd>To:</b>
<a href="mailto:bldg-rate@lists.onebuilding.org">
bldg-rate@lists.onebuilding.org</a><br>
<dd>Subject:</b> [Bldg-rate] LEED+90.1 Process/Plug Loads
Conundrum<br><br>
<dd> <br><br>
<dd>Something new occurred to me this week and I’d love to hear others’
thoughts!<br><br>
<dd> <br><br>
<dd>LEED prescribes baseline/proposed energy models to follow ASHRAE 90.1
with a caveat: the “process energy costs” must total 25% of the
baseline energy costs. By extension, 90.1 requires the same
loads/schedules be applied to the proposed model as they have to
match. As an aside, the LEED EAc1 templates appear to
calculate/check this using process energy consumption (not cost), but
that’s not what I’m getting at…<br><br>
<dd> <br><br>
<dd>I just had a typical case where I had to inflate the baseline
internal miscellaneous equipment loads to get to 25%. These
additional loads were substantial enough that when applied to the
proposed model/design, I ran into many unmet cooling hours for the
equipment capacities entered. <br><br>
<dd> <br><br>
<dd>Then I realized: We can define additional equipment electricity
loads but simultaneously apply a multiplier (in eQuest anyway – I expect
this is feasible other programs also) to reduce/negate the corresponding
heat load contributions. This results in the energy
consumption/costs showing up correctly in the final results/reports, but
does not artificially inflate the internal loads that the
baseline/proposed systems must handle.<br><br>
<dd> <br><br>
<dd>Would this practice (which incidentally can be a time saver) of
accounting for extra process/miscellaneous loads without extra thermal
contributions be in line with the intent of ASHRAE/USGBC? It would
still normalize the otherwise unstandardized process consumption/costs of
the baseline/proposed models between different building types…<br><br>
<dd> <br><br>
<dd>On the other hand, if it really is the intent of USGBC to add
arbitrary additional internal heat loads to our models that our actual
designs were not designed and sized for, does it follow that we should
allow the proposed models to autosize cooling equipment/fan capacities
and not specify them (this would seem incongruous with 90.1 to
me)?<br><br>
<dd> <br><br>
<dd> <br><br>
<dd>~Nick<br><br>
<dd> <br><br>
<dd><br><br>
<dd> <br>
</b><br>
<dd>NICK CATON, E.I.T.<br>
</b><br>
<dd>PROJECT ENGINEER<br><br>
<dd>25501 west valley parkway<br><br>
<dd>olathe ks 66061<br><br>
<dd>direct 913 344.0036<br><br>
<dd>fax 913 345.0617<br><br>
<dd>Check out our new web-site @
</i><a href="http://www.smithboucher.com">www.smithboucher.com</a> <br>
</u><br>
<dd> <br><br>
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