[BLDG-SIM] DOE2.1E oversized heating and cooling equipment?

[Liu, Bing]

The autosized heating capacity in DOE-2 is calculated based on following equation:
Heating Capacity (Btu/h) = 1.08 x Supply CFM x {(MAX-SUPPLY-T)-(DESIGN-HEAT-T)}

Supply cfm is determined from load runs to satisfy both the zone peaking heating and cooling load and is set equal to heating and cooling mode for CAV system.  So the heating capacity in Report SV-A is calculated before the system starts the hourly run.  If you input a high value for MAX-SUPPLY-T, you will get the oversized heating coil/furnace. The best way to avoid DOE-2 oversize equipment is to define the heating equipment capacity after running the Design Day. 

Bing Liu, P.E.
Research Engineer
Energy Science & Technology Directorate
Pacific Northwest National Laboratory
Voice: (509) 375-3710
Fax:    (509) 375-3614
Email:  Bing.Liu at pnl.gov
 

-----Original Message-----
From: Marceau, Medgar [mailto:mmarceau at ctlgroup.com]
Sent: Wednesday, March 12, 2003 3:26 PM
To: BLDG-SIM at GARD.COM
Subject: [BLDG-SIM] DOE2.1E oversized heating and cooling equipment?


Hello,
>  
> We are using DOE2.1E to model a house. When we use the "autosize" feature
> for sizing heating and cooling equipment, it gives us a furnace 50%
> oversized (i.e., the auto sized capacity is 50% larger than the hourly
> peak load). Does anyone know why this is so?
> 
Sincerely,
> Medgar Marceau, M.A.Sc., LEED Accredited Professional
> Building Scientist
> Construction Technology Laboratories, Inc.
> 5400 Old Orchard Road
> Skokie, IL  60077
> phone: 847-972-3154
> fax: 847-965-5416
> e-mail: mmarceau at CTLGroup.com
> 
> To learn more about CTL's services in building science and sustainability
> visit: www.ChicagoEnergyCode.com
> 
> Please visit our website: www.CTLGroup.com
> 

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