[Equest-users] FW: [Bldg-sim] Discomfort hrs

Bishop, Bill wbishop at pathfinder-ea.com
Wed Apr 7 06:39:09 PDT 2010


Sambhav,
 
Are you modeling the baseline according to Appendix G? If so, and you
are using PSZ, you should have one system per zone. If you are already
modeling one system per zone you should not be getting high unmet hours
if you let eQUEST do the autosizing.
 
If you are trying to model a PSZ with multiple zones assigned to it, you
can do a few things to reduce the unmet hours. As Carol and Rob suggest,
you can remove the heating and cooling schedules to unconditioned zones.
You should not do this for conditioned zones (zones that you want to
keep within a certain temperature range) because you will be letting the
temperatures float. Your unmet hours will go away but the virtual people
in those zones will be calling their virtual landlords complaining about
being too hot or too cold.
 
To reduce unmet hours when multiple zones are assigned to a PSZ, try the
following:
1.)     change the control zone (try assigning to the zone with most
unmet hours first)
2.)     increase/decrease people/lighting/misc loads in the trouble
zones (and copy the values to the proposed model to keep them identical)
3.)     change some interior walls to "air walls" (and copy into the
proposed model)
4.)     increase the supply air flow rate to individual zones,
especially if they are undercooled
 
Regards,
Bill
 
William Bishop, EIT, BEMP, LEED(r) AP | Pathfinder Engineers &
Architects LLP
Mechanical Engineer
 
134 South Fitzhugh Street
Rochester, NY 14608
T: (585) 325-6004 Ext. 114
F: (585) 325-6005
wbishop at pathfinder-ea.com
www.pathfinder-ea.com
P Please strive to live sustainably.
________________________________

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Carol
Gardner
Sent: Wednesday, April 07, 2010 2:32 AM
To: Rob Hudson
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Discomfort hrs
 
Yes. Only put the heating temp schedules and cooling temp schedules in
the zone you have selected as the Control Zone. If you use the
Spreadsheet option you will be able to do this easily. Use the drop down
menu and select Undefined for all other zones. 

Carol
On Tue, Apr 6, 2010 at 9:18 AM, Rob Hudson <rdh4176 at gmail.com> wrote:
If there are more than one zone assigned to the PZS, then remove the
thermostats to the extra zones.  This happened to me when i attached an
unconditioned plenum space to a PZS space.
 
On Tue, Apr 6, 2010 at 10:52 AM, Vikram Sami <vssami at yahoo.com> wrote:
Have you tried cycling your fans? If you'r doing this for ASHRAE
compliance you need to do this anyway. 

--- On Tue, 4/6/10, sambhav tiwari <tiwari.sambhav at gmail.com> wrote:

From: sambhav tiwari <tiwari.sambhav at gmail.com>
Subject: [Bldg-sim] Discomfort hrs
To: bldg-sim at lists.onebuilding.org
Date: Tuesday, April 6, 2010, 2:33 AM
 
Hi All,
          In one of project my basline building was having packaged
syngle zone system but after running i am getting lot of unmet hours for
PSZ system for each zone almost 450 hrs for basline.

Can any suggest some solution.

Thanks
Sambhav.
 
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-- 
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