18 Product Manual WHR-2
40 -5 -21 0.946 0.971 1.078 1.366
NOTE: Glycol applications are not included in the ARI certification program.
Evaporator and Condenser Delta-T Factors
Performance tables are based on a 10°F (5°C) temperature difference through the evaporator and
condenser. A temperature difference other than 10°F (5°C) will result in unit performance being
different from what is shown. Adjustment factors for applications having temperature drops
between 6°F and 16°F (3.3°C to 8.9°C) can be found in Table 3 and Table 4.
Fouling Factor
Performance tables are based on water with a fouling factor of 0.0001 ft
2
x hr x °F/BTU (0.0176 m
2
x
°C/kW) in the evaporator and 0.00025 ft
2
x hr x °F/BTU (0.044 m
2
x °C/kW) in water-cooled
condensers according to ARI 550/590-98. As fouling is increased, performance decreases. See
Table 3 and Table 4 for performance with other fouling factors.
To ensure optimum unit operation, proper water treatment must be maintained. Scaling and dirt in a
system will vary significantly depending on local water conditions. Water treatment should be
based on characteristics of the area’s water. Improper or untreated water may lead to scale build up,
erosion and corrosion in both the condenser and evaporator. McQuay will not accept
responsibility for poorly or improperly treated water.
Table 3, Evaporator Adjustment Factors
Fouling Factor
Chilled Water
Delta-T
0.0001 (0.0176) 0.00025 (0.044) 0.00075 (0.132)
°F °C Cap. Power Cap. Power Cap. Power
6 3.3 0.992 0.995 0.985 0.993 0.962 0.986
8 4.4 0.995 0.997 0.988 0.995 0.965 0.988
10 5.6 1.000 1.000 0.993 0.998 0.970 0.991
12 6.7 1.005 1.002 0.998 1.000 0.975 0.993
14 6.8 1.010 1.005 1.003 1.003 0.980 0.996
16 8.9 1.014 1.007 1.007 1.005 0.984 0.998
Table 4, Condenser Adjustment Factors
Fouling Factor
Condenser
Water Delta-T
0.00025 (0.044 0.00075 (0.132)
°° F °° C Cap. Power Cap. Power
6 3.3 1.003 0.999 0.984 1.035
8 4.4 1.002 1.000 0.982 1.037
10 5.5 1.000 1.000 0.980 1.038
12 6.6 0.984 0.973 0.977 1.042
14 7.7 0.976 0.960 0.963 1.067
16 8.8 0.968 0.946 0.948 1.092
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