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[BLDG-SIM] Simulation of Demand Controlled Ventilation



Mostly correct; item #3 below calculates minimum outside air at design conditions, and then uses this value all hours; it does not adjust hourly for the actual number of people.
----- Original Message -----
Sent: Thursday, March 20, 2003 1:28 PM
Subject: [BLDG-SIM] Simulation of Demand Controlled Ventilation

Hello,
 
There are three options for values in the min-air-sch. 
 
1.  A fraction value (ex:  0.36) in any given hour sets the MINIMUM air as a fraction of total system air flow for that hour.  The economizer is enabled in this case  so the actual outside air could be greater than the minimum if cooling is needed and outside conditions favor the use of the economizer.  NOTE:  Be careful, even if you set the minimum OA ratio in the system screen, you should still use that same ratio in the schedule.  Using a value of 1 will give 100% of the total system OA, not 100% of the minimum OA.
 
2.  A zero (0) value closes the outside air damper AND disables the economizer.  This is usually used for optimum start periods.
 
3.  A Flag value (-999) asks DOE to calculate the minimum amount of outside air needed based on the number of people in the occupancy schedule and the OA cfm/person specified in the thermal zone.  The economizer is enabled in this case so again the actual outside air could be greater than the minimum if cooling is needed and outside conditions favor the use of the economizer. 
 
For demand controlled ventilation, I've used an OA schedule flagged 24/7 (except during optimum start periods = 0).  For constant OA during occupied periods and closed OA dampers when unoccupied, I use the minimum OA fraction during occupied periods, "0" during optimum start, and Flag all unoccupied hours to ensure economizer availability.
 
Hope this helps.
 
Sheila Sagerer
Energy Opportunities, Inc
 
 
-----Original Message-----
From: postman@xxxxxxxx [mailto:postman@xxxxxxxx]On Behalf Of Aulbach, John
Sent: Thursday, March 20, 2003 1:16 PM
To: BLDG-SIM@xxxxxxxx
Subject: [BLDG-SIM] Simulation of Demand Controlled Ventilation

What does -999 do in the Min-Air-Sch? Doesn't that "vote" on what OSA is needed, and also yield to the economizer as well?
-----Original Message-----
From: Varkie Thomas [mailto:Varkie.Thomas@xxxxxxx]
Sent: Thursday, March 20, 2003 9:59 AM
To: BLDG-SIM@xxxxxxxx
Subject: [BLDG-SIM] Simulation of Demand Controlled Ventilation

We tried scheduling the outdoor air fraction in the Systems component of the DOE2.1E program by using the occupancy schedule in the Loads component.  This would vary the outdoor air based on occupancy using CO2 sensors in the Return Air.  However the schedule overrode the air-side economizer.  Can this problem be fixed in DOE2.1E?
 
Varkie Thomas
-----Original Message-----
From: Bob Ramirez [mailto:bob@xxxxxxx]
Sent: Wednesday, March 19, 2003 4:53 PM
To: BLDG-SIM@xxxxxxxx
Subject: [BLDG-SIM] Simulation of Demand Controlled Ventilation

Hello group

 

Does anyone out there have experience with simulating demand controlled ventilation in DOE2?  I am especially interested in any work that validates the use of such a model for estimating energy savings from this control scheme.  Any advice or information would be greatly appreciated.  Thanks!

 

Bob

 

 

Bob Ramírez, P.E.
Senior Engineer
Bob@xxxxxxx  , Bob.Ramirez@xxxxxxxxx

 

RER is now Itron!
http://www.RER.com/Consulting
11236 El Camino Real  San Diego, CA 92130    USA

VOICE:858.481.0081X427  FAX:858.481.7550

 

 

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