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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Well the reason I am trying to create unmet load hours is per
ASHRAE 90.1. My proposed model has slightly more than 50 unmet heating
hours and to get the difference to less than 50 ASHRAE says you should decrease
the equipment capacities on the baseline building. The space in my
building that has load problems was designed as a kitchen with a significant
amount of commercial kitchen equipment, however, the kitchen installation is
being delayed and will not be completed at this time. The equipment had
been creating quite a significant heating load, but without that the proposed
equipment cannot quite meet the load. As far as the building is concerned
I don’t see this as a problem because until the kitchen is installed the
room will most likely be used as storage, if for anything at all. ASHRAE
requires that the difference be less than 50 though, and I don’t see
anything else I could do, other than placing the equipment back into the
kitchen as though it were being installed at the time of the building
submittal. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Perhaps I am not spending enough time trying to minimize unmet
hours in the proposed model, but I am not in charge of the design, I am just
putting everything into the model. As far as I can tell I have put in all
of the variables as accurately as I can. Not to say it’s perfect,
but it’s pretty good.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Michael<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Pasha
Korber-Gonzalez [mailto:pasha.pkconsulting@gmail.com] <br>
<b>Sent:</b> Friday, July 30, 2010 3:47 PM<br>
<b>To:</b> M. Shields<br>
<b>Cc:</b> equest-users@lists.onebuilding.org<br>
<b>Subject:</b> Re: [Equest-users] Oversizing/Undersizing Equipment<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal>Michael,<o:p></o:p></p>
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<p class=MsoNormal> <o:p></o:p></p>
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<p class=MsoNormal>It depends. which is always the answer with
whole building simulation questions. From my experiences very rarely; (i
repeat) very rarely do I experience unmet loads due to under-sizing of
equipment. It has only happened to me if I am the one trying to size
equipment (where I am not a designer-I am the energy modeler.) My
point being; typically my unmet loads issues are stirred up by some input or
control toggle that I did, or didn't do within my model inputs. Sometimes
if I encounter under-heating hours it is due to my zoning pattern and the skin
losses (in heating dominated climates) are significant that my perimeter depth
zoning isn't as accurate as it could be.<o:p></o:p></p>
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<p class=MsoNormal> <o:p></o:p></p>
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<p class=MsoNormal>Where the daily goal of us simulators is to create models
that don't have unmet load hours, or as very little as possible it is
entertaining that you are trying to work backwords abit. lol.
But I recognize the analytical trait and good-job for seeking an
answer. I can only give you what my experiences have been, and
there is so much to learn and understand about the unmet-hours phenomena keep
looking for more answers and explanations.<o:p></o:p></p>
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<p class=MsoNormal> <o:p></o:p></p>
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<p class=MsoNormal>In terms of your project, you might not be experiencing
unmet load hours because of how you have specified your inputs in your model
(regardless if they are linked to sizing-ratios). What is the
climate of your project? What is the building occupancy type? What type
of extreme loads are you seein<span style='color:#1F497D'>his </span>g on your
building directly or indirectly? Did you input your equipment capacities
or are you auto-sizing?, Etc., etc. It depends. tell us more
about your project.<o:p></o:p></p>
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<p class=MsoNormal> <o:p></o:p></p>
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<p class=MsoNormal style='margin-bottom:12.0pt'>Pasha<o:p></o:p></p>
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<p class=MsoNormal>On Thu, Jul 29, 2010 at 3:23 PM, M. Shields <<a
href="mailto:mshields@fstrategies.com" target="_blank">mshields@fstrategies.com</a>>
wrote:<o:p></o:p></p>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Hi
Everyone,<o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>I
have been messing with the equipment sizing ratio in equest and came across an
interesting litte dilemma. I was playing with the “Heat sizing
Ratio” on the System Heating->Coil Cap/Control tab to see how it
affects my unmet hours. As I decrease the ratio here I see in the reports
that the system size does in fact decrease, yet no matter how low I make the
ratio, I never have unmet hours. This appears to be because the
supplemental heat increases as the equipment size decreases. Is there a
way to limit supplemental heating as well, or how would I be able to make my
system have unmet hours? I am using a heat pump system.<o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Thanks,<o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Michael
Shields <o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p>
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<p class=MsoNormal style='margin-bottom:12.0pt'><br>
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<p class=MsoNormal><o:p> </o:p></p>
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