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RE: [EnergyPlus_Support] RE: Adding more chillers doesn't reduce the autosized value





..or 1.25 in Sizing:Parameters which applies to all zone sizing (plus 0.5 in the object Sizing Factor

 

James V Dirkes II, PE, BEMP, LEED AP
www.buildingperformanceteam.com
Energy Analysis, Commissioning & Training Services
1631 Acacia Drive, Grand Rapids, MI 49504 USA
616 450 8653

 

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of fpasserini.tn@xxxxxxxxx
Sent: Friday, October 11, 2013 6:32 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] RE: Adding more chillers doesn't reduce the autosized value

 

 

If I model a baseline model according to ASHRAE 90.1-2007 and two boilers are connected in parallel (e.g. in System 5) shall I use 1.25 as "zone heating sizing factor" in the object Sizing:Zone and 0.5 in "Sizing Factor" in the object Boiler:HotWater? 

Best Regards



---In energyplus_support@xxxxxxxxxxxxxxx, <jim@...> wrote:

Dear Hisham,

An autosizing value always represent the entire load serve by the autosized component.  When there is more than one component (e.g., chillers) on a single loop, EACH component is assigned 100% of the autosize value.  Not very intuitive, but that’s how it works in E+.

If you want each chiller to have 50% of the autosized value, assign 0.50 to the “Sizing Factor”.

 

James V Dirkes II, PE, BEMP, LEED AP
www.buildingperformanceteam.com
Energy Analysis, Commissioning & Training Services
1631 Acacia Drive, Grand Rapids, MI 49504 USA
616 450 8653

 

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of hisham.rashrash
Sent: Thursday, October 10, 2013 6:50 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Adding more chillers doesn't reduce the autosized value

 

 

Dear all,
I am modeling baseline for some project, and I am trying to follow ASHRAE's 90.1-2007 section G3.1.3.7 "Type and Number of Chillers (Systems 7 & 8)" by adding more chillers until no chiller's size is above 2813[kW] (refer to table G3.1.37). The problem is no matter how many chillers I add, this doesn't reduce the autosized value! it is always the same=4258257.73[W] for all chillers, while I expected to have this value divided on chiller's number I add, for example, for one chiller it was autosized to 4258257.73[W], for two chillers I expected it to be 4258257.73[W]/2=2129128.865[W], while it was autosized to 4258257.73[W] for each chiller!
Please advise.

Thank you very much,
Hisham.



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