| Selection Procedure Nominal Data And Dimensions
Roughing-in Dimensions
The dimensional drawings illustrate overall measurements of the chiller. The recommended space envelope indicates
clearances required to easily service the CenTraVac
chiller. A view of the unit is superimposed on this
drawing with unit support feet shown.
All catalog dimensional drawings are subject to change. Current submittal drawings should be referred to for detailed
dimensional information. Contact the local Trane sales
office for submittal and template information.
Evaporator and Condenser Data Tables
Evaporator and condenser data is shown in the Performance Data section. Data
includes minimum and maximum water flow limits and
water connection sizes for all standard pass configurations and tube type. Pressure drops are calculated by the CenTraVac computer
selection program.
Part Load Performance
The CenTraVac chiller possesses excellent performance characteristics over its
full range of operation. The multi-stage direct drive
compressor enables stable and efficient operation
over a wide range of capacities, virtually eliminating the need for energy
wasting hot gas bypass typically found on single stage
chillers.
An in-depth examination of project- specific conditions and energy rate structures should be performed to appropriately
evaluate total energy costs over a period of time.
TRACE® ,
Trane’s unique energy analysis program, is particularly well suited for this
type of analysis, as well as for economic evaluation of
equipment and system alternatives.
Local utilities may offer substantial monetary rebates for centrifugal chillers
with specific operating kW ratings. Contact your local
utility representative or Trane sales office for
further information.
The electrical rate structure is a key component of an economic evaluation. Most power bills are now constituted of
anywhere from one-half to two- thirds of the bill being
a demand charge, often "ratcheted" over a
period of 12 months. The full load power consumption of the chiller plant is likely to set the kW peak and demand charge for the
billing period. This places an increased emphasis on
the need to keep the full load consumption of the
chiller plant low.
There are a number of variables that should be considered in developing an accurate chiller load profile to use for measuring
how one machine compares with another machine at part
load. The use of outdoor air economizers, variations in chiller sequencing
and chiller plant load optimization strategies should
be considered. The use of a decoupled or primary/secondary water loop is generally
acknowledged as the simplest, most efficient way to
control multiple chiller water plants. This control strategy results in one chiller operating at a more fully loaded condition
rather than multiple chillers operating at part load,
which would require more pumping energy.
ARI Standard 550 provides chiller performance certification for the full load
condition and the "APLV" (application part
load value). The APLV uses a generic weighted chiller
load profile to simplify certification of part load performance data. Although these values are not necessarily a precise indicator
of actual energy use, they do provide a valuable basis
for comparison. |
