Vl Hydronic-Side System Design; Storage Tanks; Hydronic Side Circulators - Econar GeoSource Ultra GW Series Installation And Operating Instructions Manual

8.
Stop the pump, and let
the solution
stand
for
about
15
minutes.
9.
Flush the solution by
adding a fresh water supply
to
the pail. Flush until
the leaving
water
is
clear. Note
-
observe
local
codes
for
disposal.
VI.
HYDRONIC.SIDE SYSTEM
DESIGN
This
section deals
with
some cofilmon practices
used
when coupling
the
ECONAR
GeoSource
Ultra
hydronic
heat pumps
to
the
space
conditioning
heat
exchanger.
There are so many
possible applications
for
hydronic
systems
that they cannot
all
be
covered
in
this
text.
Hopefully
these ideas can
help in
many
of your
system
designs.
qNote
-
Actual
systems must be constructed to
all
appropriate
codes and according to
accepted
plumbing
practices.
eCaution
- Alwa),s
use
copper pipe
on the
hydronic
side
of
the system.
elmportant
-
Pressure/Temperature
port fittings
must
be installed
in
the entering
and
leaving hydronic lines
of
the heat
pump.
A.
Storage Tanks
elmportant
-
The heat pump must be
coupled
to
the
space
conditioning
system
through
a
water
storage tank.
e-Important
-
The guideline
for the total
fluid
storage
in
the
system
is
10
gallons of fluid for
each ton of hydronic
heat
pump capacity
(examp1e, 50 gallons minimum
for
a
5-ton unit). Size the
storage
tank
for
the
difference
between the amount of
fluid in
the smallest hydronic loop
and what the
system requires.
If
in doubt,
size the storage
tark for
the total capacity
of
the
heat
pump. A
properly
sized
storage
tank
eliminates
many problems
with
multiple
zone
hydronic
systems. These problems include
excessive
leaving water
temperature
if
a
single
zone
cannot dissipate heat
quickly
enough, and hydronic
flow
reduction through the
heat
pump when only
one zone is
calling.
This
may
occur because the hydronic circulating
pump
is
normally sized
to
provide
the
heat pump's
required
flow with all
zones calling.
In
applications that
use multiple smaller
zones, storage tanks
absorb
the
relatively large amount
of
energy supplied
by
the
heat
pump
in
order
to
provide longer run
times and
less
compressor cycling for
the heat
pump.
Storage tanks
also
serve
to
dispense energy
in
small amounts
so that
the
conditioned zones
have
time
to
absorb
heat
without
requiring high
discharge
water
temperatures.
(The
only
instance where a
storage
tanks is
not required is when
the
heat
pump is coupled to
a
large
heat exchanger containing
the
recommended
amount
of fluid
capable
of
absorbing
the entire capacity of
the heat pump.)
Insulated water
heaters are commonly used
for
storage
hnks.
eNote
-
Always
check
local
codes
to
ensure
water
heaters can be used as storage tanks. Using
the
electric
elements
in
the
tank
as
a secondary heat source
to the heat
8
pump
is
appealing
in
some
applications,
but
special
Listing
Agency Certifications may be required
by
many
local
codes. Specially listed
water
heaters are
available.
While all hot
water tanks are insulated on
the top
and
sides, many
do not
have insulation on the bottom. An
insulated
pad
beneath uninsulated tanks
will
reduce
energy loss to
the
floor.
elmportant
-
The hydronic flow into the
storage tank
(particularly
a water heater) must
not be restricted.
If
the
water
heater has an internal diffirser
"dip
tube,,,
cut
it off
at
approximately
12 inches
into
the tank.
The tank temperatue can be controlled
with a
simple
Aquastat
or
a
setpoint controller. The
setpoint controller
senses
tank water temperature
and outside air
temperature
to
increase
the tank
temperature
as the
outside
air
becomes colder. This control
scheme
provides
the
highest
heating efficiencies by
requiring
the
lowest possible water
temperature to
heat the
space. Setting the optimal
design
temperatures
in tlle
conffoller is difficult,
and the
simple
Aquastat
does have
its
advantages.
To
help
in
setpoint
control,
the
following
equation
can be used:
Reset
Ratio
=
Desiqn Water Temp
-
Indoor
Design Temp
Indoor
Design Temp -
Outdoor Design Temp
B.
Hydronic
Side
Circulators
Hydronic circulator pumps transfer
the
energy
supplied
by ECONAR's
hydronic
heat pumps to
the water
srorage
tank.
Select
a quiet
operating
pump
with the ability
to
)
supply
the required
flow
rate at the
system pressure drop.
The
circulator supplying
the heat pump
musr be
placed in
the water
supply
line into the unit to provide
the
best
pump performance.
Individual
zone
circulators must also
be placed
in
the supply lines of
the heat exchangers they
serve. These
pumps
are
often
used as the on/off
control
mechanism for
the zone they supply
as
shown in
Figure 4.
Zone
valves are also commonly
used
for
this
purpose
using
a
cofilmon pump
as
shown in Figure
5.
eNote
-
Select a cofilmon pump at
the
total flow of
all
the
zones
and the
highest pressure drop
of
any
one
parallel
zone. Small Grundfos pumps (230
Vac)
should
be
used as circulator pumps.
These pumps are
impedance
protected and do
not require additional fusing if
powered
directly from
the heat
pump.
VCAUTION
-
Never
operate
with
hydronic flow
rates
less than specified.
Low flow
rates,
or no
flow,
may
cause
the
unit to
shut down
on a pressure lockout or
may
cause
afreeze rupture
of
the heat exchanger.
Circulator pumps must
be
sized
to provide
the
required
flow to
a heat
pump
heat exchanger
at its
corresponding
system pressure
drop.
This
system pressure drop
can
be
calculated from
the pressure
drop through
the
piping,
plus
the pressure drop of
the water
storage tank,
and
plus
the
pressure drop through the heat pump heat
exchanger.
Table
4
shows the hydronic water-flow
requirements
and
pressure drop (dP),
and Table 3
shows the dp multiplier