Product data

47
Vertical ground loop — This system is used in vertical
borehole applications. This design is well suited for retrofit
applications when space is limited or where landscaping is
already complete and minimum disruption of the site is de-
sired. The vertical ground loop system contains a single
loop of pipe inserted into a hole. The hole is back-filled and
grouted after the pipe is inserted. The completed loop is
concealed below ground. The number of loops required de-
pends on ground conditions, heating and cooling require-
ments, and the depth of each hole.
Hybrid systems — In some applications, it may be bene-
ficial to incorporate a cooling tower into the ground loop
system to reduce the overall cost. A hybrid system discards
excess heat into the air and increases the cooling perfor-
mance of the ground loop.
Condensate drainage
Venting — Condensate lines should be properly vented to
prevent fan pressure from causing water to hang up in the
piping. Condensate lines should be pitched to assure full
drainage of condensate under all load conditions. Chemical
treatment should be provided to remove algae in the con-
densate pans and drains in geographical areas that are
conducive to algae growth.
Trapping — Condensate trapping is an essential necessity
on every water source heat pump unit. A trap is provided
to prevent the backflow of moisture from the condensate
pan and into the fan intake or downstream into the
mechanical system. The water seal or the length of the trap
depends on the positive or negative pressure on the drain
pan. As a rule of thumb, the water seal should be sized for
1 in. for every 1 in. of negative pressure on the unit. The
water seal is the distance from the bottom of the unit con-
densate piping connection to the bottom of the condensate
drain line run-out piping. Therefore, the trap size should be
double the water seal dimension.
Horizontal units — Horizontal units should be sloped to-
ward the drain at a
1
/
4
in. per foot pitch. If it is not possible
to meet the pitch requirement, a condensate pump should
be designed and installed at the unit to pump condensate
to a building drain. Horizontal units are not internally
trapped; therefore an external trap is necessary. Each unit
must be installed with its own individual trap and means to
flush or blow out the condensate drain. The design of a
common trap or vent for multiple units is not acceptable.
The condensate piping system should not be designed with
a pipe size smaller than the drain connection pipe size.
Vertical units — Vertical units utilize a condensate hose
inside the cabinet that acts as a trapping loop, therefore an
external trap is not necessary. Each unit must be installed
with its own vent and means to flush or blow out the
condensate drain lines. Do not install a common trap or
vent on vertical units.
Water conditioning
In some applications, maintaining proper water quality
may require the use of higher corrosion protection for
the water-to-refrigerant heat exchanger. Water quality var-
ies from location to location and is unique for each job.
Water characteristics such as pH value, alkalinity, hard-
ness, and specific conductance are of importance when
considering any WSHP application. Water typically
includes impurities and hardness that must be removed.
The required treatment will depend on the water quality as
well as type of system. Water problems fall into three main
categories:
1. Scale formation caused by hard water reduces the
heat transfer rate and increases the water pressure
drop through the heat exchanger. As water is heated,
minerals and salts are precipitated from a solution
and deposited on the inside surface of the pipe or
tube.
2. Corrosion is caused by absorption of gases from the
air coupled with water on exposed metal. Corrosion
is also common in salt-water areas.
3. Organic growths such as algae can reduce the heat
transfer rate by forming an insulating coating on the
inside tube surface. Algae can also promote corrosion
by pitting.
NOTE: In most commercial water loop applications,
Aquazone™ WSHP units use a copper water-to-refrigerant
heat exchanger. Units can also be equipped with a
cupronickel heat exchanger for applications where water is
outside the standard contaminant limits for a copper heat
exchanger.