[BLDG-SIM] Screw chiller performance curves

Steve,

Thanks for this update.

Two additional questions:

1) will the new version of DOE2.2 that models the screw chillers and the VFD chillers be incorporated into PowerDOE? (maybe a question for Jeff Hirsch)

2) are there / will there be any default curves for air-cooled screw chillers? I have been trying to model this without much success so far. I created my own curves, but the results don't appear to make sense. When I created an output report, the modified values of EIR based on my curves made good sense, but the chiller kW that is being shown makes no sense at all. I haven't finished debugging this yet, but wonder if anyone has any suggestions.

Sincerely,

Alec Stevens
DMI
p: 617-527-1525x105
f: 617-527-6606
e: astevens@xxxxxxxxxx

----- Original Message -----

From: Steve Gates

To: BLDG-SIM@xxxxxxxx

Sent: Wednesday, January 16, 2002 3:31 PM

Subject: [BLDG-SIM] Screw chiller performance curves

James Hirsch & Associates is currently implementing new chiller algorithms in DOE-2, and defaults performance curves for screw chillers will be included.

For both reciprocating and screw chillers, the program will use different performance curves depending on the number of compressors in the machine. The program will also model centrifugal chillers with variable-speed drives. Since some of these curves utilize new types of CURVE-FITS, they require a new version of DOE-2.2 which won't be released for another month or two.

In the meantime, for current versions of DOE-2.2, the following models a water-cooled screw:

"ScrewH2O-Cap-fCHWT&LCT" = CURVE-FIT

   TYPE = BI-QUADRATIC-T

   INPUT-TYPE = DATA

   IN-TEMP1 = ( 44.0, 44.0, 44.0, 44.0, 44.0, $ CHW T

                48.0, 48.0, 48.0, 48.0, 48.0,

                52.0, 52.0, 52.0, 52.0, 51.0,

                40.0, 40.0, 40.0, 40.0, 40.0)

   IN-TEMP2 = ( 85.0, 75.0, 70.0, 95.0, 100., $ ECT

                85.0, 75.0, 70.0, 95.0, 100.,

                85.0, 75.0, 70.0, 95.0, 100.,

                85.0, 75.0, 70.0, 95.0, 100.)

   OUTPUT = ( 1.00, 1.07, 1.10, 0.92, 0.89, $ Capacity ratio

                1.09, 1.16, 1.18, 1.00, 0.96,

                1.18, 1.24, 1.26, 1.09, 1.05,

                0.92, 0.99, 1.02, 0.85, 0.83) ..

"ScrewH2O-EIR-fCHWT&LCT" = CURVE-FIT

   TYPE = BI-QUADRATIC-T

   INPUT-TYPE = DATA

   IN-TEMP1 = ( 44.0, 44.0, 44.0, 44.0, 44.0, $ CHW T

                48.0, 48.0, 48.0, 48.0, 48.0,

                52.0, 52.0, 52.0, 52.0, 51.0,

                40.0, 40.0, 40.0, 40.0, 40.0)

   IN-TEMP2 = ( 85.0, 75.0, 70.0, 95.0, 100., $ ECT

                85.0, 75.0, 70.0, 95.0, 100.,

                85.0, 75.0, 70.0, 95.0, 100.,

                85.0, 75.0, 70.0, 95.0, 100.)

   OUTPUT = ( 1.00, 0.85, 0.78, 1.20, 1.31, $ EIR ratio

                0.94, 0.81, 0.74, 1.13, 1.24,

                0.90, 0.77, 0.71, 1.07, 1.17,

                1.06, 0.89, 0.82, 1.27, 1.39) ..

$ Two circuits, one compressor/circuit

"ScrewH2O-EIR-fPLR&dT-1Comp/Ckt" = CURVE-FIT

   TYPE = QUADRATIC

   INPUT-TYPE = DATA

   INPUT = ( 1.00, 0.75, 0.50, 0.25, 0.10)

   OUTPUT = ( 1.00, .906, .538, .332, .141) ..

$ Two circuits, two compressors/circuit

"ScrewH2O-EIR-fPLR&dT-2Comp/Ckt" = CURVE-FIT

   TYPE = QUADRATIC

   INPUT-TYPE = DATA

   INPUT    = ( 1.00, 0.75, 0.50, 0.25, 0.10)

   OUTPUT = ( 1.00, .842, .664, .289, .151) ..

"A Generic Screw Chiller" = CHILLER

   TYPE             = ELEC-HERM-REC

   ELEC-INPUT-RATIO = .202

   CAPACITY-FT      = "ScrewH2O-Cap-fCHWT&LCT"

   EIR-FT           = "ScrewH2O-EIR-fCHWT&LCT"

   EIR-FPLR         = "ScrewH2O-EIR-fPLR&dT-1Comp/Ckt"

   etc.

   ..



Hope this helps!


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