[Equest-users] Equest, fan coils and Ashrae

[Bishop, Bill]

Nick,
 
This is a good question and not one that I see discussed much in the
forums. Fan power is directly proportional to flow rate, and directly
proportional to static pressure. For combining multiple FCU zones into
one, I'd combine the flow rates (supply, return, OA etc.) and
heating/cooling capacities if the units are already selected. Use the
total static pressure (or kW/cfm) of a single unit, and the coil head of
a single unit.
 
Regards,
Bill
 
William Bishop, PE, 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 Sustainability - less is more.
________________________________

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of
Nicholas Lander
Sent: Thursday, September 02, 2010 11:51 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Equest, fan coils and Ashrae
 
Folks, 
This may be a stupid question but it has me stumped. I'm primarily
concerned with fan coil units, but any HVAC system raises similar
issues:
 
ASHRAE Appendix G lets you group zones together into thermal blocks as
long as they have the same HVAC systems and loads and orientation. So,
for example, hotel rooms can be grouped as each is identical to the
next. The question is, how do you model the HVAC of this thermal block?
 
For example, hotel rooms use fan coil units for cooling. A single FCU
uses X-amount of energy based on fan size and pressure drop. So how do
you accurately model fan energy when grouping several zones, and hence
several FCUs, together?
 
Thanks
Nick
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