Product Manual PM WSC/WDC 27
ARI Standard 550/590-98 for Centrifugal or Screw Water -Chilling Packages and associated manuals define
certification and testing procedures and tolerances of all units that fall within the application rating conditions.
Leaving chilled water temperature............................................40°F to 48°F
Entering condenser water temperature ....................................60°F to 95°F
Rating outside the range of the certification program may be listed or published but must include a statement
describing such. The standard rating conditions are:
Leaving chilled water temperature............................................44°F
Evaporator waterside field fouling allowance.........................0.0001
Chilled water flow rate................................................................2.4 gpm/ton
Entering condenser water temperature ....................................85°F
Condenser waterside field fouling allowance.........................0.00025
Condenser water flow rate ........................................................3.0 gpm/ton
IPLV/NPLV Defined
Part load performance can be presented in terms of Integrated Part Load Value (IPLV), which is based on ARI
standard rating conditions (listed above), or Non-Standard Part Load Values (NPLV), which is based on
specified or job site conditions. IPLV and NPLV are based on the following equation from ARI 550/590.
DCBA
NPLV
or
IPLV
12.045.042.001.0
1
+++
= or DCBA 12.045.042.001.0
Where: A = kW/ton at 100% Where: A = COP at 100%
B = kW/ton at 75% B = COP at 75%
C = kW/ton at 50% C = COP at 50%
D = kW/ton at 25% D = COP at 25%
Tolerances
The ARI test tolerance, per ARI Standard 550/590-98, for capacity (tons), power input per ton (kW/ton), and heat
balance is:
% . ( . % )
%
Tolerance x FL
DTFLx FL
= − +
105 007
1500
Where: FL = Full Load
DTFL = Chilled Water Delta-T at Full Load