[Equest-users] Fwd: Exhaust Fans

[Shaun Martin]

Hi Simge,

 

You have two options where the exhaust air flow rate is higher than supply
air flow rate:

 

1. if the exhaust fan schedule is equal to or longer than the supply fan
schedule, then re-balance the supply air in your model to account for
transfer air from other zones, or

 

2. if the exhaust fan schedule is shorter than the supply fan schedule, you
can de-rate the exhaust fan flow and fan power (eg 1000 cfm for 1 hour = 250
cfm for 4 hours). 

 

Shaun

 

Shaun Martin LEED AP

Principal

Shaun Martin Consulting

2060 Pine Street

Vancouver, BC V6J 4P8

P: 604-789-1095

E: smartin at shaunmartinconsulting.com

 

 

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Simge
Andolsun
Sent: Tuesday, November 12, 2013 8:16 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Fwd: Exhaust Fans

 


Another option can be balancing the high amount of air extracted from the
zone with infiltration instead of from the air handler, but I believe this
would increase the number of unmet hours in the system. As per Appendix G,
the total unmet hours of the baseline and as-built models need to be 300 or
less. Thus, this option did not seem like a good approach to me as well.

 

Thank you very much,

Best Regards,

S.Andolsun, PhD 


 

---------- Forwarded message ----------
From: Simge Andolsun <simgeandolsun at gmail.com>
Date: Tue, Nov 12, 2013 at 9:52 AM
Subject: Exhaust Fans
To: "equest-users at lists.onebuilding.org"
<equest-users at lists.onebuilding.org>



Dear eQuest users,

 

I am trying to model a lab building in compliance with ASHRAE 90.1 to
compare it with an as built model that represents the real case as described
in Appendix G. The actual building (the as built model) has a few zones
which have exhaust air flow rate higher than supply air flow rate as per the
building schedules. I unfortunately do not have any information regarding
the operation schedule of the exhaust fans. When I model the exhaust air
flow rates of these zones to be always lower than the zone supply air flow
rate, then the actual building is not represented closely enough. When I
increase the zone supply air flow rate such that it is always equal to the
actual exhaust air flow rate, then the zone air flow rate is assumed to be
higher than it actually is increasing the overall energy consumption of the
building. eQuest does not allow for the exhaust air flow rate of a zone to
be higher than the supply air flow rate which would result in high unmet
hours in the zone. In order to make a reasonable comparison between the
baseline and the as built models as per Appendix G, how do you think I
should represent the exhaust fans in these two models? and why? Would you
also explain the settings I should use in eQuest to model the case you are
suggesting? I would appreciate it very much.

 

Thank you very much,

Best Regards,

S.Andolsun, PhD 

 

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