Trane RTHD manual Application Considerations, Water Treatment

Application Considerations

Series Chiller Arrangements Another energy-saving strategy is to design the system around chillers arranged in series, on the evaporator, condenser, or both.The actual savings possible with such strategies depends on the application dynamics and should be researched by consulting yourTrane Systems Solutions Representative and applying theTrane System Analyzer program. It is possible to operate a pair of chillers more efficiently in a series chiller arrangement than in a parallel arrangement. It is also possible to achieve higher entering-to-leaving chiller differentials, which may, in turn, provide the opportunity for lower chilled water design temperature, lower design flow, and resulting installation and operational cost savings.TheTrane screw compressor also has excellent capabilities for “lift,” which affords an opportunity for savings on the evaporator and condenser water loops.

Like series arrangements on the evaporator, series arrangements on the condenser may enable savings.This approach may allow reductions in pump and tower installation and operating costs. Maximizing system efficiency requires that the designer balance performance considerations for all system components; the best approach may or may not involve multiple chillers, or series arrangement of the evaporators and/or condensers. This ideal balance of design integrity with installation and operating cost considerations can also be obtained by consulting aTrane representative and applying theTrane System Analyzer program.

Water Treatment

The use of untreated or improperly treated water in chillers may result in scaling, erosion, corrosion, and algae or slime buildup. It is recommended that the services of a qualified water treatment specialist be engaged to determine what treatment, if any, is advisable.Trane assumes no responsibility for the results of using untreated or improperly treated water.

Water Pumps

Where noise limitation and vibration-free operation are important,Trane strongly encourages the use of 1750-rpm (60 Hz), 1450-rpm (50 Hz) pumps. Specifying or using 3600-rpm (60 Hz), 3000-rpm (50 Hz) condenser water and chilled water pumps must be avoided, because such pumps may operate with objectionable levels of noise and vibration. In addition, a low frequency beat may occur due to the slight difference in operating rpm between 3600-rpm (60 Hz), 3000-rpm

(50 Hz) water pumps and Series R chiller motors. Important Note:The chilled water pump must not be used to stop the chiller.

Acoustic Considerations

For chiller sound ratings, installation tips, and considerations on chiller location, pipe isolation, etc., refer to theTrane Water-Cooled Series R Chillers Sound Ratings and Installation Guide. Using the information provided in this bulletin, contact a certified sound consultant to aid in proper mechanical room design and treatment.

Figure 1. Typical series chiller arrangement

RLC-PRC020-EN 11