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Application Considerations |
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Application Considerations
Certain application constraints should be considered when sizing, selecting and installing Trane air-cooled Series R®
chillers. Unit and system reliability is often dependent upon properly and completely
complying with these considerations. Where the
application varies from the guidelines presented, it
should be reviewed with your local Trane sales engineer.
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 as listed in Table W-1.
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
ELASTOMERIC vibration eliminators. Spring isolators have proven to be of little
benefit on air-cooled Series R chiller installations
are not recommended. An acoustical engineer should always be consulted in critical sound 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 power levels for Trane air-cooled Series R 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 swing and routine 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
assuring a sufficient flow of air across the condenser heat transfer surface. Two detrimental conditions are possible and
must be avoided if optimum performance is to be
achieved: 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. Both warm air recirculation
and coil starvation cause reductions in unit efficiency and capacity because of the higher head pressures associated with them.
The air-cooled Series R chiller offers an advantage
over competitive equipment in these situations. Performance is minimally affected in many restricted air flow situations due to its
unique condensing coil geometry. Also, through its
advanced Adaptive Control™ microprocessor logic, the chiller will stay on-line where competitive
chillers would shut down.
Trane’s unique Adaptive Control microprocessor has the ability to understand
the operating environment of the chiller and adapt to
it by first optimizing its performance and second,
staying on line through abnormal conditions. For example, high ambient temperatures
combined with a restricted air flow situation will
generally not cause the air-cooled Series R chiller to shut down. Competitive
chillers would typically shut down on a high pressure
nuisance cut-out in these conditions.
Debris trash, supplies, etc. should not be allowed to accumulate in the vicinity of the air-cooled Series R chiller. Supply air
movement may draw debris into the condenser coil,
blocking spaces between coil fins and causing coil
starvation.
Special consideration should be given to low ambient units. Condenser coils and fan discharge must be kept free of snow or
other obstructions to permit adequate airflow for
satisfactory unit operation. |
