[Bldg-sim] Variable Speed Screw Chiller Curves

[Dan Russell]

Well, I’m going over a year back into the archives, but hopefully someone can help.  I’m modeling a project with 500 Ton Carrier Evergreen Water-Cooled Screw Chillers and would like to take advantage of the part-load efficiency benefits.  It appears that Dan Nall posted custom efficiency curves for this specific equipment a while back, but when I use them in eQUEST my cooling energy gets tripled (from 800 MWh to 2450 MWh) as compared to the default eQUEST curves for Water-cooled Screw chillers.  Does anyone have experience using these curves effectively?  Am I misinterpreting the curve data?  Are they intended for something other than eQUEST inputs?  Or are the default eQUEST curves unrealistically efficient?

Thanks for any input,

Dan Russell
Engineering Incorporated

From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Dan Nall
Sent: Tuesday, August 26, 2008 1:17 PM
To: Kingsley,Michael L.; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Variable Speed Screw Chiller Curves


Try these on for size;

"VFDSCrew EIR fPLR" = CURVE-FIT

TYPE = CUBIC

INPUT-TYPE = DATA

INDEPENDENT = ( 1, 0.75, 0.5, 0.25 )

DEPENDENT = ( 1, 0.97307, 1.01436, 1.3616 )

..

"Carrier-EIR-fCHWT&CWT" = CURVE-FIT

TYPE = BI-QUADRATIC-T

INPUT-TYPE = COEFFICIENTS

COEFFICIENTS = ( 0.767051, -0.0236208, 0.0004375, 0.0024939, 0.0002337,

-0.000418 )

..

"Carrier-EIR-fPLR&dT" = CURVE-FIT

TYPE = BI-QUADRATIC-RATIO&DT

INPUT-TYPE = COEFFICIENTS

COEFFICIENTS = ( -0.0230025, 0.902964, 0.0935993, 0.00347819,

-2.45759e-005, -0.00196462 )

..

"Carrier-CAP-fCHWT&CWT" = CURVE-FIT

TYPE = BI-QUADRATIC-T

INPUT-TYPE = COEFFICIENTS

COEFFICIENTS = ( 0.448509, 0.0185587, -0.00028125, 0.00306901,

-5.0201e-005, 0.000108475 )




-----Original Message-----
From: "Kingsley, Michael L."
Sent: Aug 26, 2008 2:15 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Variable Speed Screw Chiller Curves


Does anyone have DOE-2 performance curves for a variable speed screw chiller (I believe the Carrier Evergreen 23XRV is the only one now) that they would be willing to share?

Thanks in advance.

Michael Kingsley

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