Trane GEH 006 Manual page 14

Figure 22: Model GEH with waterside economizer package
Note: Condensate overflow is not available with
the waterside economizer option.
Figure 23: Waterside economizer system
14
Features and
Benefits
Waterside Economizer (option)
The beauty of the waterside economiz-
er is it's ability to take advantage of
any loop condition that results in cool
water temperatures. A prime example
would be during fall, winter and spring
when cooling towers have more ca-
pacity than required and could be con-
trolled to lower temperatures for
economizer support.
Another more common inexpensive
means of free comfort cooling in-
cludes buildings systems where pe-
rimeter heating and core cooling are
needed. In this system, the perimeter
units extract heat from the building
loop while in the heating mode, forc-
ing the building loop temperature to
drop. Where as, the core are of a build-
ing may require cooling in summer or
in winter based upon lighting, people
and equipment.
If the water-source system design con-
tained an economizing coil option, the
moderate temperature loop water cir-
culated through a core water-source
system can provide an inexpensive
means to satisfy room comfort with-
out operating the water-source heat
pump's compressor.
During economizer mode, fluid enters
the unit, and passes by a water tem-
perature sensing bulb. This tempera-
ture sensing bulb determines whether
the two position, three-way valve will
direct the water through the waterside
economizing coil, and to the heat
pump condenser, or through the con-
denser only. If the water temperature
is 55 F or less, fluid will flow into the
economizing coil, while simultaneous-
ly halting mechanical operation of the
compressor. Mechanical cooling will
continue on a call for second stage
from the thermostat.
The factory built waterside economiz-
er is available on all GEH models, and
all 12 1/2 to 25 GEV models. The 1/2
through 5-ton GEV may be ordered to
accept a field provided waterside
economizing package.
WSHP-PRC001-EN