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Equipment not designed for operation at AHRI Standard 550/590 test conditions of 44.00°F leaving and 54.00°F entering chilled-fluid temperatures, and with 85.00°F entering and 94.30°F leaving condenser-fluid temperatures, shall have maximum full-load kW/ton (FL) and part-load rating requirements adjusted using the following equations:
FLadj = FL/Kadj
PLVadj = IPLV.IP/Kadj
Kadj = A × B
where
FL = full-load kW/ton kW/ton value from Table 6.8.1-3
FLadj = maximum full-load kW/ton rating, adjusted for nonstandard conditions
IPLV.IP = IPLV.IP value from Table 6.8.1-3
PLVadj = maximum NPLV rating, adjusted for nonstandard conditions
A = 0.00000014592 × (LIFT)4 — 0.0000346496 × (LIFT)3 + 0.00314196 × (LIFT)2 — 0.147199 × (LIFT) + 3.93073
B = 0.0015 × LvgEvap + 0.934
LIFT = LvgCond — LvgEvap
LvgCond = full-load condenser leaving fluid temperature (°F)
LvgEvap = full-load evaporator leaving temperature (°F)
The FLadj and PLVadj values are only applicable for centrifugal chillers meeting all of the following full-load design ranges:
• 36.00°F ≤ LvgEvap ≤ 60.00°F
• LvgCond ≤ 115.00°F
• 20.00°F ≤ LIFT ≤ 80.00°F
Manufacturers shall calculate the FLadj and PLVadj before determining whether to label the chiller per Section 6.4.1.5. Compliance with 90.1-2007, 2010, 2013, 2016 or combinations thereof, shall be labeled on chillers within the scope of the standard.
Centrifugal chillers designed to operate outside of these ranges are not covered by this standard.
Example (Section 6.4.1.2.1)
Path A 600-ton centrifugal chiller Table 6.8.1-3:
FL = 0.5600 kW/ton
IPLV.IP = 0.5000 kW/ton
LvgCond = 91.16°F
LvgEvap = 42.00°F
LIFT = 91.16 — 42 = 49.16°F
A = 0.00000014592 × (49.16)4 — 0.0000346496 × (49.16)3 + 0.00314196 × (49.16)2 — 0.147199 × (49.16) + 3.93073 = 1.02331
B = 0.0015 × 42.00 + 0.934 = 0.99700
Kadj = 1.02331 × 0.99700 = 1.02024
FLadj = 0.5600/1.02024 = 0.5489 kW/ton
PLVadj = 0.5000/1.02024 = 0.4901 kW/ton

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