Selection Procedure
Selection
The CenTraVac™ centrifugal chiller product line provides more than 200,000 individual unit selections over a capacity range of 170 through 3500 tons. Chiller selections and performance data can be obtained through the use of the CenTraVac chiller selection program available in local Trane sales offices. This program can provide a list of chiller selections optimized to closely match specific project requirements. Nominal data and physical data for typical
Trane Model Number
The Trane model number defines a Trane CenTraVac with its particular component combination. These components along with the project design conditions are required to determine chiller performance from the CenTraVac computer selection program:
•Compressor size and voltage
•Evaporator bundle size, bundle length, and number of water passes
•Condenser bundle size, bundle length, and number of water passes
•Leaving chilled water temperature, evaporator water flow rate, temperature drop through the chiller
•Entering condenser water temperature, condenser water flow rate, and temperature rise through the condenser
•Water side fouling factors for the evaporator and condenser
•Refrigerant type for operating on
Performance
The CenTraVac computer selection program provides performance data for each chiller selection at the full load design point and part load operating points as required.
The Trane computer selection program is certified by ARI in accordance with ARI Standard 550/590. To assure that the specific chiller built for your project will meet the required performance, and to ensure a more troublefree
The CenTraVac computer selection program has the flexibility to select chillers for excessive field fouling allowances.
Fouling Factors
ARI Standard 550/590 includes a definition of clean tube fouling. Recommended field fouling allowances have not changed on a relative basis; the standard fouling adjustment is a 0.0001 increment from 0.0000 “clean” on the evaporator and 0.00025 increment from 0.0000 “clean” on the condenser.
Chiller specifications should be developed using the most current standard fouling factors.
It should be noted that changing the number of water passes or water flow rates may significantly alter the performance of a particular chiller.
To obtain the maximum benefit from the wide range of selections available, designers are encouraged to develop performance specifications and use the computer selection program to optimize their selections. This will allow the selection of the particular compressor-
Unit Performance With Fluid Media Other Than Water
CenTraVac chillers can be selected with a wide variety of media other than water. Typically used media include ethylene glycol or propylene glycol either in the evaporator, condenser or both. Chillers using media other than water are excluded from the ARI 550/590 Certification Program, but are rated in accordance with ARI 550/590. Trane factory performance tests are only performed with water as the cooling and heat rejection media. For media other than water, contact the local Trane sales office for chiller selections and information regarding factory performance testing.
Flow Rate Limits
Flow rate limits for all pass combinations for evaporators and condensers are tabulated in the data section for the appropriate chiller family. For applications outside of these limits, contact your local Trane office.
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