Specifications

26
Natatorium DesigN maNual
The vertical configuration
in Figure 14 is very
popular in hotel and
residential applications
because of their
compact footprint and
2-side service access.
These PV and NV
models are available
with or without pool
water heating. The
maximum size is limited
to 100 lb/h capacity.
There are a multitude
of other configurations
available should a
horizontal unit or outdoor
packaged system suit
the project better. The
heat rejection can also
be to a geothermal
loop, dry cooler or
cooling tower.
Purge Economizer Layout
This configuration has enhanced air quality control
capabilities and also offers economizer operation.
These systems are designed with multiple dedicated
duty exhaust fans. The first exhaust fan (EF1) is sized
to maintain the room’s negative pressure by exhausting
10% more room air than is introduced to the space
as code mandated ventilation outdoor air. The second
exhaust fan (EF2) sized to allow for full purge/evacuation
of the space with a 100% outdoor air mode.
Figure 16 shows a unit in “Normal Operation” where
EFI maintains the room’s negative pressure. EFI can
be unit mounted or remotely installed with its intake
located above the whirlpool whenever appropriate.
EF2 is normally off and operates only when a purge or
economizer demand exists.
The outdoor air intake is set to introduce the code
required ventilation outdoor air (aka Minimum OA) until
the system goes into Purge or Economizer when it
opens to 100%.
These minimum outdoor air and EF1 airstreams at
vastly different conditions present a perfect opportunity
for heat recovery. Seresco provides unit mounted heat
recovery between these two air streams using a glycol
run-around loop. The coils just slip into the airstreams of
this unit configuration. This approach to heat recovery
offers the best performance and design flexibility while
staying in the smallest possible cabinet. Figure 17
shows a unit in “Normal Operation” with the glycol heat
recovery coils in place.
Adding the glycol run around loop heat
recovery option to your Seresco unit in a
northern installation will typically realize a one
year payback on your investment!
If the system design has remote exhaust fans, the glycol
run around loop can still be used for heat recovery.
A significant added benefit to heat recovery is the
tempering of the outdoor air before it can mix with
the system air. Tempered outdoor air will not create
condensation problems during the cold weather. In
northern climates it is very common to add a separate
heating coil for the outdoor air if heat recovery is not
being used.
NOTE: Traditional supply & return fan configurations with
a mixing box are not a good choice for a Natatorium
application. There are three significant shortcomings
compared to the Seresco method:
• A traditional mixing box modulates air from 0-100%
and cannot offer heat recovery on the minimum
outdoor air and exhaust air streams.
• The fan motor consumption can be double of the
Seresco method.
Figure 15 – Typical Hotel and Therapy Pool Layout