DESIGN ALERT ON CHILLER EFFICIENCY
ISSUE:
Improvements in chiller efficiencies offered by various manufacturers.
BACKGROUND:
Present VA criteria calls for 0.67 kW/ton maximum power consumption for electric,
water cooled, centrifugal and rotary screw chillers. Various major manufacturers can
now supply chillers with a maximum power consumption of 0.62 kW/ton i.e. an
improvement of efficiency of over 7 percent.
DISCUSSION:
Four major manufacturers were contacted and they provided the following information
for a nominal 1000 ton centrifugal chiller
NAME OF COMPANY
REFRIGERANT
FULL LOAD
PART LOAD
EFFICIENCY
EFFICIENCY
TRANE
R-123
0.52
0.52 OR LESS
YORK
R-134a
0.58
0.59
R-22
0.58
0.55
McQUAY
R-134a
0.62
0.62 OR LESS
CARRIER
R-134a
0.62
0.62 OR LESS
Above chiller efficiencies are based on kW/ton, and Part load efficiencies are based on
ARI standard 550-92, IPLV (Integrated Part Load Value) standard ARI conditions.
The chiller efficiency may vary according to the size of the chiller and its actual
operating conditions. The actual operating condition is defined as APLV (Application
Part Load Value) in the ARI Standard 550. Based on above data, it's recommended by
the FM's HVAC Professional Group that consultants meet a goal of not to exceed a
maximum power consumption of 0.62 kW/ton for full load and 0.62 kW/ton for part load
conditions.:
RECOMMENDATIONS/CONCLUSION:
1. Specify chillers for maximum efficiency which can be met by at least three
manufacturers for full load and part load.
2. VA criteria is being changed requiring consultants to meet a goal of 0.62 kW/ton for
full load and 0.62 kW/ton for part load efficiencies.
FOR ADDITIONAL INFOR MATION:
Contact Satish Sehgal at 202.565.5032 in the Standards Service (187C).
21 June 1995
FM -187C-DA38
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