[Equest-users] Chiller curve ball

[Sami, Vikram]

Ok - so I'm probably doing this all wrong.

I am trying to model a York scroll chiller in EQUEST. The table below illustrates the Part Load rating Data

Load %

 Capacity (Tons)

 Cond. EWT (°F)

 Cond. LWT (°F)

 Compressor kW

EER

COP

EIR

100

135.8

85

95

104.1

15.6

4.6

0.217391

83.3

116.8

79.4

87.9

81

17.3

5.1

0.196078

66.7

96.9

73.5

80.4

60.1

19.3

5.7

0.175439

50

73.5

66.7

71.8

41.7

21.2

6.2

0.16129

33.3

48.2

65

68.4

26.6

21.7

6.4

0.15625

16.7

23.6

65

66.6

13.1

21.7

6.4

0.15625


eQUEST doesn't seem to have a scroll chiller option - I assume screw is the closest thing to it.

As far as I can tell - you need to define 3 performance curves:

1.       A curve that defines the EIR based on the condenser water temp
"York - Temp vs EIR" = CURVE-FIT
   TYPE             = BI-QUADRATIC-T
   INPUT-TYPE       = DATA
   INDEPENDENT-1    = ( 85, 79.4, 73.5, 66.7, 65, 65 )
   INDEPENDENT-2    = ( 95, 87.9, 80.4, 71.8, 68.4, 66 )
   DEPENDENT        = ( 0.217391, 0.196, 0.175, 0.161, 0.156, 0.156 )
   ..

2.       A curve that defines the part load based on the condenser water temp
"York Temp vs Part Load" = CURVE-FIT
   TYPE             = BI-QUADRATIC-T
   INPUT-TYPE       = DATA
   INDEPENDENT-1    = ( 85, 79.4, 73.5, 66.7, 65, 65 )
   INDEPENDENT-2    = ( 95, 87.9, 80.4, 71.8, 68.4, 66 )
   DEPENDENT        = ( 1, 0.833, 0.667, 0.5, 0.333, 0.167 )
   ..

3.       A curve that  defines the EIR based on the part load.
"York Part Load vs EIR" = CURVE-FIT
   TYPE             = QUADRATIC
   INPUT-TYPE       = DATA
   INDEPENDENT      = ( 1, 0.833, 0.667, 0.5, 0.333, 0.167 )
   DEPENDENT        = ( 0.217, 0.196, 0.175, 0.161, 0.156, 0.156 )
   ..


When I apply these curves to my chiller, my cooling energy goes up by 30%. Seems like a lot.      Is this reasonable or am I doing something wrong with my curve selection?

Muchas Gracias in advance
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