[Equest-users] 90.1 Supply Fan Energy

[joe@thespinnakergroupinc.com]

Ok that's a perfect recipe for lower cooling and heating requirements and relatively higher fan power, esp with the low humidity climate with cool sumner nights and the 24 hour fan operation. 
Ashrae fan power allowances almost always increase the fan power consumption over the default, they also increase cooling due to the excessive heat gain, from the fan, into the supply airstream.

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----- Reply message -----
From: "M. Shields" <mshields at fstrategies.com>
To: <equest-users at lists.onebuilding.org>
Subject: [Equest-users] 90.1 Supply Fan Energy
Date: Thu, Apr 7, 2011 11:37 am
The building is a residential high rise for seniors in climate zone 3B using PTHP for heating and cooling.  For all of the residential spaces the fan runs 24/7 as ASHRAE 90.1-2004 requires that the system run continuously during occupied hours.  Cooling set point of 78, heating setpoint of 72.  Also the apartments are continuously ventilated through exhaust risers for the bathrooms and kitchens of each area, so I suppose it should not be surprising to have a high vent fan consumption, however, what surprised me was how much it increased going from the eQUEST default values to my calculated 90.1 values.   From: Joe Fleming [mailto:joe at thespinnakergroupinc.com] 
Sent: Thursday, April 07, 2011 11:25 AM
To: 'M. Shields'; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] 90.1 Supply Fan Energy I have personally never seen fan power equal the total of cooling and heating power, except in certain climate zones where an economizer can run often or when the exhaust/ventilation fan power, not associated with cooling/heating, is high.Not sure if you are stilling looking for help here.  What does your fan schedule look like?  Is your fan set to run 24 hrs?What climate zone are you in?  What are your space cooling and heating temperature set-points? -----Original Message-----
From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of M. Shields
Sent: Wednesday, April 06, 2011 3:22 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] 90.1 Supply Fan Energy Hi all, I am in the process of breaking out the fan energy from my HVAC system per ASHRAE 2004 G3.1.2.1, following G3.1.2.9.  The amount of energy coming from my fans seems massive and I’m not sure if that is typical, or if I’ve messed something up.  I started by setting the temperature difference of 20 degrees between supply and desired temp (55/75 cooling and 90/70 for heating) and specified 62.1-2004 ventilation for outside air.  I then ran equest and used the SV-A reports to get supply CFM for each system.  From that number I then used Table G3.1.2.9 to get BHP for each system, which I then converted to kW using the formula in ASHRAE.  I then took that number and divided by CFM to get kw/CFM and entered this number on the system->fan tab.  When I go to the SV-A report the system kW is exactly what I calculated it to be, but the energy required for my ventilation fans is about the same as my heating and cooling load combined, which seems outrageous.   Is this typical?  Have I entered it In the wrong way? I would think fan consumption would typically be a fraction of the actually heating and cooling energy.  Thanks for any thoughts. ____________________________
Michael Shields
Facility Strategies Group, LLC1012 Market Street, Suite 307Fort Mill, SC 29708Phone: 803-493-4507Fax: 803-548-2511
Email: mshields at fstrategies.com
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