Earth Loop - Econar GeoSource Invision 3 Q Series Installation And Operating Instructions Manual

V.
EARTH LOOP WATER
PIPING
Since water is
the source
of
energy
in
the
wintertime
and
the
energy sink
in
the
summertime, good water supply is
possibly
the
most important requirement
of
a
geothermal
heat
pump
system
installation. There
are
two common
tlpes of water supplies, closed
loop
systems and
open
loop
systems.
A.
Closed
Loop Applications
A
closed
loop
system
recirculates the same
water/antifreeze solution through
a
closed system
of
underground high-density polyethylene
pipe.
As the
solution passes
through the
pipe,
it
collects heat
(in the
heating mode) that is
being transferred
from
the
relatively
warm surrounding soil through the
pipe
and
into
the
relatively cold solution.
The solution is circulated
to
the
heat
pump, which pulls
heat
out
of
the
solution, and then
back through the
ground to extract more
heat
from
the
earth.
The GeoSource
Invision3 is designed
to
operate
on either
vertical or horizontal closed
loop
applications' Vertical
loops
are
rypically installed
with
a
well
drilling rig up to
200 feet deep or
more. Horizontal
systems are
typically
installed
with excavating
or ffenching equipment
approximately six to eight feet deep,
depending on
geographic
location
and
length
of pipe used. Earth loops
must
be sized
properly for
each
particular geographic
TOIFROM
CLOSED LOOP
area,
soil type, and
individual capacity requirements.
tContact
your
local installer or ECONAR's Customer
Support
for loop
sizing requirements
in your
a"rea.
Since
normal
wintertime operating entering water
temperatures
(EWT) to
the heat
pump
are
from
25oF
to
32'F,the solution
in
the earth
loop must include
antifreeze.
GTF
and
propylene
glycol
are
common
antifreeze
solutions. GTF
is
methanol-based antifreeze,
which should be
mixed
50Vo
with
water to achieve freeze
protection
of
10oF. Propylene
glycol
antifreeze solution
should be
mtxed25Vo
with water to obtain a
15oF
freeze
protection. DO
NOT mix
more than25%o
propylene
glycol with
water
in
an
attempt
to
achieve a
lower
than
15oF
freeze
protection,
since
more concentrated mixtures
ofpropylene glycol become too viscous
at
low
temperatures and cannot be
pumped through
the
earth
loop.
Insufficient amounts
of
antifreeze may result in
a
freeze
rupture of *re unit, and can cause
unit shutdown
problems during
cold
weather operation (when
the
heat
pump
experiences the
longest run time)
due
to
loop
temperatures
falling below the freeze
protection
of the
anifreeze.
Flow
rate requirements
for
closed loops are
higher than
open
loop
systems because
water temperatures supplied to
the heat
pump
are
generally
lower
(see
Table
2).
From
2.5 to 3.0
gallons per minute
(GPM)
per ton
are
required
for proper operation
of
the heat
pump
and the
earth
coupled heat exchanger.
\
f
--ll
--J
Figure
L
- Closed
Loop
Water Plumbing
6
IN
OUT
PmPPAK
hsree/
Taperahre
(P/T) Ports
lt
il
il