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Application Considerations |
Certain application constraints should be considered when sizing, selecting and installing Trane TM air-cooled 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 sales engineer.
Note: The terms water and solution are used interchangeably in the following paragraphs.
UNIT SIZING
Unit capacities are listed in the "Performance Data" section. Intentionally oversizing a unit to assure adequate capacity is not recommended.
Erratic system operation and excessive compressor
cycling are often a direct result of an oversized chiller. In addition, an oversized unit is usually more expensive to
purchase, install, and operate. If oversizing is
desired, consider using two units.
UNIT PLACEMENT
1
Setting The Unit
A base or foundation is not required if the selected unit location is level and strong enough to support the unit’s operating
weight (see "Weights" section of this catalog).
For a detailed discussion of base and foundation construction, refer to the Trane Reciprocating Refrigeration Manual.
Manuals are available through the local Trane office.
2
Isolation and Sound Emission
The most effective form of isolation is to locate the unit away from any sound
sensitive area. Structurally transmitted sound can be
reduced by using spring isolators. Spring isolators
are generally effective in reducing vibratory noise generated by compressors, and
therefore, are recommended for sound sensitive installations. An acoustical engineer should always be consulted on critical applications.
For maximum isolation effect, water lines and electrical conduit should also be isolated. Wall sleeves and rubber
isolated piping hangers can be used to reduce the sound
transmitted through water piping. To reduce the sound transmitted through electrical conduit, use flexible electrical conduit.
State and local codes on sound emissions should always be considered. Since
the environment in which a sound source is located
affects sound pressure, unit placement must be carefully evaluated. Sound
pressure and sound power levels for chillers are
available on request.
3
Servicing
Adequate clearance for evaporator and compressor servicing should be provided.
Recommended minimum space envelopes for servicing are
located in the dimensional data section and can serve as a guideline for
providing adequate clearance. The minimum space
envelopes also allow for control panel door swing and
routing maintenance requirements. Local code requirements may take precedence.
4
Unit Location
a General
Unobstructed flow of condenser air is essential to maintain chiller capacity and operating efficiency. When determining
unit placement, careful consideration must be given to
assure a sufficient flow of air across the condenser heat transfer surface. Two detrimental conditions are possible® and must be avoided: warm air recirculation
and coil starvation. Warm air recirculation occurs when
discharge air from the condenser fans is recycled back to the condenser coil inlet. Coil starvation occurs when free airflow
to the condenser is restricted.
Condenser coils and fan discharge must be kept free of snow or other obstructions
to permit adequate airflow for satisfactory unit
operation.
Debris, trash, supplies, etc., should not be allowed to accumulate in the vicinity of the air-cooled chiller. Supply air
movement may draw debris into the condenser coil,
blocking spaces between coil fins and causing coil
starvation.
Both warm air recirculation and coil starvation cause reductions in unit efficiency and capacity because of the higher
head pressures associated with them. In addition, in
more severe cases, nuisance unit shutdowns will result from excessive head pressures. Estimates of the degree of efficiency and
capacity reduction in such situations can be
determined. Consult your local Trane sales engineer.
Cross winds, those perpendicular to the condenser, tend to aid efficient operation in warmer ambient conditions,
however, they tend to be detrimental to operation in
lower ambients or when hot gas bypass is used due to the accompanying loss of adequate head pressure. As a result, it is
advisable to protect air-cooled chillers from
continuous direct winds exceeding 10 miles per hour in
low ambient conditions.
Low Ambient Operation — 20-60 Ton models — Human Interface Recommendations
When the temperature outside is sub-zero, who wants to be out there monitoring
or troubleshooting diagnostics? Because we understand
a service technician’s reluctance to do this, we recommend using a Remote Human
Interface (RHI) panel. The service technician can
troubleshoot and diagnose in the comfort of a mechanical room. |
