Econar GeoSource DualTEK GV Series Installation And Operating Instructions Manual page 15

The
condensate line
as
it
leaves the U
bend
ofthe
condensate trap must
be at least 3" below
the base
ofthe
heat
pump.
This requires
the
U
bend to
be
6,'below
the
unit
to give
the upward
portion of
the
U bend
a
3"
lift.
The
condensate trap
should be vented after
the
U
bend.
The
condensate line
should be
pitched away
from
the
unit
a
minimum of
1/8" per
foot. ff
the
unit produces
an
odor
in
the
cooling
mode,
the condensate ftap or line
may
be
plugged, or
the
unit
may not
be
pitched correctly.
Bleach
may
be
poured down
the condensate drain in
the heat
pump to
kill
any
bacterial
gowth
in
the condensate
line.
V[I.
UNIT SIZING
Selecting
the
unit
capacity
of
a
GeoSource
DualTEK
geothermal
heat
pump requires
four
things:
A)
Earth Loop Configuration
and Design Water
Temperatures.
B)
Hydronic
Side
Heat Exchanger Operating
Temperatures.
C) Building
Heat Loss/Heat Gain.
D)
Temperature Limitations.
A. Earth Loop Configuration
and
Design Water Temperatures
Loop
configurations include
the open and
closed loop
varieties.
Heat
pump flow
rate requirements vary
depending on loop
conhguration
(see Table
6).
Consult
ECONAR'
s
Engineering Specifications Manual for
capacities
at
different loop entering water
temperatures
and
hydronic leaving
water temperatures. Remember to
use
the correction factors for
GeoSource
DualTEK
units
found in
the Engineering Specifications manual.
2.
Open Loop Systems
On
an open loop
system the
design water temperature
will
be the
well
water temperature in your
geographic region.
Many
cold climates
are
in
the
50oF range
for
well
water
temperature.
If
your
well
water
temperatures are lower
than 50oF,
for
instance Canadian well
water
can be as
low
as
43T,
the
flow
rate must
be increased to avoid leaving
water
temperatures
below
the freezing
point. If
well
water
temperafures are above 50nF,
as
in
some southern
states
where well
water
temperatures are above 70oF, the
flow
rates may
need to
be increased to dump
heat more
efficiently in
the cooling mode.
Varying well
water temperatures will
have
little
effect on
unit capacity in
the cooling
mode (since the well
is
connected to
the heat
pump
condenser),
but can have
large effects on
the capacity in
the heating mode (since
the
well
is
connected
to
the evaporator).
If
well
water
temperatures are
to exceed 70oF,
special considerations,
such
as closed
loop
systems,
should
be addressed.
B.
Hydronic
Side
Heat Exchanger
Operating Temperatures
The
hydronic
side heat exchangers discussed in
section
IV
are designed to operate at
a
speciflc
fluid
supply
temperature. This operating temperature will
have to
be
supplied to
the selected
space
conditioning
heat
exchanger by the heat
pump.
The manufacturers
or
distributors of
the hydronic
side heat exchangers publish
the capacity
of
their equipment
at
different operating
temperatures and
fluid flow
rates.
These capacities
and
operating
temperatures
are
required to
select the heat
pump to
be used
in
the
system.
When sizing
the
hydronic
side of
the
GeoSource
DualTEK
heat
pump, remember to
use the
minimum
hydronic
loop temperature that
will
supply
the necessary
heating capacity to
the conditioned
space.
If
an
intermediate
heat exchanger is used
between
the
closed
hydronic loop
and the open
hydronic loop
as
pictured in
Figure
3,
expect a
10oF
operating temperature
difference between
the
two
circuits.
For example,
if
the
direct coupled
storage tank is at
120oF, expect
the
maximum
operating temperature of
the open
circuit
connected through
an intermediate
heat
exchanger
to be
110T.
This occurs when connecting
open
loop
applications to
the closed
loop
systems
with plate
heat
exchangers
or
with indirect
water
heaters.
C.
Building Heat Loss/fleat Gain
The
space
load
must be estimated accurately
for
any
successful
HVAC installation.
There
are
many guides or
computer programs available
for load estimation
including
the
ECONAR
GeoSource Heat Pump
Handbook, Manual
J, and
others. After
the heat
loss/heat
gain is completed, loop EWT's
are established,
and
hydronic
side heat
exchanger conditions
are determined,
the heat pump
can
now
be selected using
the
hydronic
and
forced air
heat
pump
data found in
the Engineering
Specifications.
Remember to
use the correction factors
for
the GeoSource
DuaITEK
models that
are
listed
in
the
Engineering Specifications manual.
Choose the capacity
of
the heat pump
based on both
the
forced air heating
and
cooling loads,
and the hydronic heating load.
13
L. Closed Loop Systems
Closed loop
systems
use
a
heat exchanger of high
density
polyethylene pipe buried underground to supply
a
tempered water solution back to
the heat
pump.
Closed
loops
operate at
higher
flow
rates than open loops
since
the
entering water temperature (EWT)
is
lower.
The
loop
EWT
supplied to
the heat
pump
has
a
great
effect
on
the
capacity of
the
unit in
the
heating
mode.
Earth loops in
cold climates
are
normally
sized
to supply
a
wintertime
EWT
to the heat
pump from
32oF down to 25oF,
which
minimizes
the
installation
cost
of
the earth
loop
and
still
maintains proper
system
operation.
The GPM
requirements and pressure
drops
for
loop pump sizing
are
shown in
Table
6.