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Coefficient 2 of the Part Load Performance Curve input range

asked 8 years ago

elvin's avatar

updated 7 years ago

I'm wondering if anyone knows the input range for "Coefficient 2 of the Part Load Performance Curve" for variable speed headered pumps.

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answered 8 years ago

updated 8 years ago

The EnergyPlus.idd file does not specify an input range for the pump coefficients:

N7, \field Coefficient 1 of the Part Load Performance Curve
     \default 0.0
N8, \field Coefficient 2 of the Part Load Performance Curve
     \default 1.0
N9, \field Coefficient 3 of the Part Load Performance Curve
     \default 0.0
N10, \field Coefficient 4 of the Part Load Performance Curve
     \default 0.0

However, the simulation will throw an error if pump power is negative, so you should probably stay away from negative coefficient values. You can see where the program is using the coefficients in the pump power calculation; there may be some other implicit limits based on what's physically realistic for pump operation.

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answered 8 years ago

updated 8 years ago

From the docs, the fraction of full load power is defined according to this equation

FractionFullLoadPower=C1+C2×PLR+C3×PLR2+C4×PLR3

c1, c2, c3, c4 = (0, 1, 0, 0) is the EnergyPlus default as highlighted in the EnergyPlus example files.

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Not sure why the Mathjax isn't displaying correctly, when I edit the question it's working right.

Julien Marrec's avatar Julien Marrec  ( 8 years ago )

@Julien Marrec The markdown was confusing the asterisks as italics markers. Escaping them fixed the equation. I don't know why it's handled differently in the preview.

Neal Kruis's avatar Neal Kruis  ( 8 years ago )

Ah ok, I didn't think about that. Next times I'll use \times (seems like markdown is not working in the comment box)

Julien Marrec's avatar Julien Marrec  ( 8 years ago )

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Asked: 8 years ago

Seen: 432 times

Last updated: Apr 13 '16