Dear Camilo,
Users will never do what an energy modeler expects J.
My standard approach to this sort of question is to:
1. determine a reasonable approach
2. imagine myself explaining the approach to a group of peers
3. If I can make the explanation with a straight face (with confidence), then I move forward.
4. There is almost always more than one approach to a problem, and almost never a ?perfect? solution. Give careful thought, consider all of the factors, and make a decision!
So much for the general approach!
For your specific question, I think it is reasonable to assume that the users will adjust fan speeds in proportion to their need for cooling or heating. If that is true, then it makes sense (to me) to define a variable speed fan with a roughly linear part load curve. I would use a ?roughly linear? curve because the multi-speed fan does not have a typical cubic flow / power response. You could plot flow vs. power for each speed of a typical fan coil and then approximate that curve.
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 Camilo Velez :::Green Factory:::
Sent: Wednesday, September 19, 2012 8:40 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Fan coil two velocity
Hello Jim
Regarding this topic I have a question: right now I'm modeling some terminal units that have 3 fan speeds (H/M/L), but because in the real building the users can change the speed when they want, I'm not sure how to model the fans; what would be the best practice for energy modeling: Should I do what you say in the previous message and use a variable speed fan with a linear variation between the low and the high speed? Or go for the a constant fan with the High speed only?
Thank you.2012/9/18 Jim Dirkes <jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
You might consider using a Fan:VariableVolume and also define the fan such that the minimum flow is the same as low speed and the power coefficients are linear between low speed power and high speed power?. something like what I show below.
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 andresdagm
Sent: Tuesday, September 18, 2012 9:22 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Fan coil two velocity
good morning,
i am wondering who may I model a fan coil two velocity (off/low/high)
this fan coil only work for cooling
Also how can i do to set up the setpoint temperature.
I generally work in DB and I hav e export this equpment (including chillers,fan for ventilation..) but I am in troubles with this.
thank you
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