Catalogue

RLC-PRC042D-EN 7
Application Considerations
Certain application constraints should be considered when sizing, selecting and installing Trane
RTAE chillers. Unit and system reliability is often dependent upon proper and complete compliance
with these considerations. Where the application varies from the guidelines presented, it should
be reviewed with your local Trane account manager.
Note: The terms water and solution are used interchangeably in the following paragraphs.
Water Treatment
The use of untreated or improperly treated water in chillers may result in scaling, erosion,
corrosion, and algae or slime buildup. This will adversely affect heat transfer between the water
and system components. Proper water treatment must be determined locally and depends on the
type of system and local water characteristics.
Neither salt nor brackish water is recommend for use in Trane air-cooled RTAE chillers. Use of either
will lead to a shortened life. Trane encourages the employment of a qualified water treatment
specialist, familiar with local water conditions, to assist in the establishment of a proper water
treatment program.
Foreign matter in the chilled water system can also increase pressure drop and, consequently,
reduce water flow.
For this reason it is important to thoroughly flush all water piping to the unit before making the final
piping connections to the unit.
The capacities given in the Performance Data section of this catalog are based on water with a
fouling factor of 0.0001°F·ft²·h/Btu (in accordance with AHRI 550/590). For capacities at other fouling
factors, see Performance Selection Software.
Effect of Altitude on Capacity
At elevations substantially above sea level, the decreased air density will decrease condenser
capacity and, therefore, unit capacity and efficiency.
Ambient Limitations
Trane chillers are designed for year-round operation over a range of ambient temperatures. The air-
cooled model RTAE chiller will operate in ambient temperatures of:
• Standard Ambient Range = 32 to 105°F (0 to 40.6°C)
• Low Ambient Range = 0 to 105°F (-17.7 to 40.6°C)
• Extreme Low Ambient Range = -20 to 105°F (-28.9 to 40.6°C)
• High Ambient Range = 32 to 125°F (0 to 52°C)
• Wide Ambient Range = 0 to 125°F (-17.7 to 52°C)
The minimum ambient temperatures are based on still conditions (winds not exceeding five mph).
Greater wind speeds will result in a drop in head pressure, therefore increasing the minimum
starting and operating ambient temperature. The Adaptive Frequency™ microprocessor will
attempt to keep the chiller on-line when high or low ambient conditions exist, making every effort
to avoid nuisance trip-outs and provide the maximum allowable tonnage.
Water Flow Limits
The minimum water flow rates are given in the chapter “General Data,” p. 16 of this catalog.
Evaporator flow rates below the tabulated values will result in laminar flow causing freeze-up
problems, scaling, stratification and poor control. The maximum evaporator water flow rate is also
given. Flow rates exceeding those listed may result in very high pressure drop across the
evaporator and/or evaporator tube erosion.