Bypass mechanism for energy recovery during mild condition

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Hi,

One of my LEED project received a standard comment as:

*Energy recovery is modeled for credit in the Proposed Case. Provide
further information regarding the energy recovery efficiency, verify that
outside air is modeled with zero flow in both the Baseline and Proposed
Case during unoccupied periods when fans are cycled on to meet unoccupied
setback temperatures unless health or safety regulations mandate an
alternate minimum flow during unoccupied periods (in which case, the
unoccupied outside air rates should be modeled identically in the Baseline
and Proposed Case), and indicate the bypass mechanism used to bypass the
energy recovery during mild conditions.*
I need to know,what exactly i need to do in E-quest model.as per my
understanding,i need to Keep Fan operation on by putting the fixed set
point temp. control with bypass mechanism.
But how exactly it will consider schedule for unoccupied hours.And how
bypass mechanism will serve the purpose during mild condition?
Please guide to resolve this query.
[image: Inline image 1]

vishal jagdale's picture
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Joined: 2015-05-30
Reputation: 0

For unoccupied hours, you can simply use a min-outside air schedule forcing your outdoor air ratio to 0 on unoccupied hours.
See the Outside air tab.

[cid:image001.jpg at 01D15FF4.388FEB70]

Patrick Lapierre_ing.
plapierre at bpa.ca

De : Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] De la part de Vishal Jagdale
Envoy? : 5 f?vrier 2016 09:02
? : equest-users at lists.onebuilding.org
Objet : [Equest-users] Bypass mechanism for energy recovery during mild condition

Hi,

One of my LEED project received a standard comment as:

Energy recovery is modeled for credit in the Proposed Case. Provide further information regarding the energy recovery efficiency, verify that outside air is modeled with zero flow in both the Baseline and Proposed Case during unoccupied periods when fans are cycled on to meet unoccupied setback temperatures unless health or safety regulations mandate an alternate minimum flow during unoccupied periods (in which case, the unoccupied outside air rates should be modeled identically in the Baseline and Proposed Case), and indicate the bypass mechanism used to bypass the energy recovery during mild conditions.
I need to know,what exactly i need to do in E-quest model.as per my understanding,i need to Keep Fan operation on by putting the fixed set point temp. control with bypass mechanism.
But how exactly it will consider schedule for unoccupied hours.And how bypass mechanism will serve the purpose during mild condition?
Please guide to resolve this query.
[Inline image 1]

Patrick Lapierre's picture
Joined: 2015-01-28
Reputation: 0

Vishal,

If you want the fan to come on during the night when heating or cooling is needed, then select ?Cycle On Any? for Night Cycle Control. You can find it for the airside system of interest in the ?Night Cycle Control? tab under ?Fans.? Keeping the fan off all night may cause unmet load hours.

[cid:image004.png at 01D16016.D1903150]

And if you want to enable the economizer overnight, then enter 0.001 for the overnight hours in the schedule. See the Help screen for MIN-AIR-SCH.
[cid:image006.png at 01D16016.5D497FE0]

Keith Swartz, PE | Senior Energy Engineer
Seventhwave
608.210.7123 seventhwave.org

Keith Swartz2's picture
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Joined: 2015-04-29
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