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<TITLE>RE: [Bldg-sim] Residential or Nonresidental? And sizing for PTAC units.</TITLE>
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<P><FONT SIZE=2>Loren---<BR>
<BR>
You are correct in treating the hotel rooms as residential spaces. With condo projects, I have served the Appendix G model corridors or first floor offices with a HVAC system that makes more sense, such as packaged rooftop units. There is wording in Appendix G about parts of the building that fall into other uses:<BR>
<BR>
Exceptions to G3.1.1:<BR>
(a) Use additional system type(s) for non-predominant conditions<BR>
(i.e., residential/nonresidential or heating source)<BR>
if those conditions apply to more than 20,000 ft2 of conditioned<BR>
floor area.<BR>
<BR>
This might not apply to your project because of the area threshold, but suggests using different HVAC systems when you have spaces of different end use.<BR>
<BR>
As far as AppG PTAC efficiencies go, I would use the highest capacity in the equation and use that in the model (Resulting EER = 8.805) since you have larger loads. In an actual project, they would just have to install multiple 1.25 ton PTACs in the room to meet the load.<BR>
<BR>
Good luck,<BR>
Andrew<BR>
<BR>
<BR>
-----Original Message-----<BR>
From: bldg-sim-bounces@lists.onebuilding.org on behalf of Loren Appin<BR>
Sent: Sun 3/9/2008 12:30 AM<BR>
To: bldg-sim@lists.onebuilding.org<BR>
Subject: [Bldg-sim] Residential or Nonresidental? And sizing for PTAC units.<BR>
<BR>
Hi All,<BR>
<BR>
I'm modeling a 6 story hotel, and am confused with how I should classify the<BR>
building. The hotel is all guest rooms, and is not really mixed use. So<BR>
according to ASHRAE this seems that it would fall under the residential<BR>
category, and I would be using PTAC or PTHP systems. Under table G3.1.1A it<BR>
specifically says hotels are considered residential building types, not just<BR>
space types... so I assume I'm correct? However, would I use a VAV or PSZ<BR>
system for areas that are not technically guest rooms, or does this not<BR>
matter as a hotel is considered a residential "building type"?<BR>
<BR>
<BR>
Also, when modeling a PTAC system it appears to me that you would get the<BR>
EER information from 6.8.1D using the equation, however, sometimes it my<BR>
system summary gives me a peak/capacity of a unit as 30KBtu or even 40 for<BR>
one room and I know that PTAC units usually don't go much about 20. So<BR>
would the equation in this table still hold? Finally, if I am getting<BR>
varying capacities for each unit as would be expected, would you suggest<BR>
taking an average of all the systems, and then use this capacity as the one<BR>
to enter into the equation to get the EER and then apply this EER to all<BR>
systems across the board?<BR>
<BR>
Thanks so much for the help!<BR>
<BR>
*Loren Appin*<BR>
<BR>
Energy Engineer<BR>
<BR>
*Silpa Inc.*<BR>
s i m p l e . s c i e n t i f i c . s u s t a i n a b l e<BR>
<BR>
AMERICAS | MIDDLE EAST | INDIA<BR>
<BR>
www.silpa.com | Mob: +971.50.9250895<BR>
<BR>
</FONT>
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