Specifications

27
POPULAR CONFIGURATIONS AND SYSTEM DESIGNS
• On a pool application the mixing box is placed after
the evaporator coil. This means conditioned air is
exhausted! The gross evaporator coil output is not
what gets delivered to the space.
Figure 18 shows a unit in “Purge-
Economizer mode”. There are
three significant benefits to this
configuration:
1. 100% air purge capability
available at any time. The
operator can super-chlorinate
(shock) the pool, and ventilate
the space with 100% outdoor air to quickly clear out
any airborne chemicals.
2. It also allows for a means to deliver a complete air
change of the space should it require a quick purge.
3. Built-in economizer operation. All controls and
mechanical equipment are already in place to operate
in economizer cooling and dehumidification modes
whenever the outdoor air conditions are suitable. This
offers the operator the most economical year round
system operation.
4. This configuration consumes significantly less
energy than traditional supply/return fan economizer
systems with a mixing box because of the specific
duty exhaust fans. They only operate when needed
compared to the supply and return fan configuration
that has both full sized fans operating year round.
EF1 is a very small horsepower fan. EF2 operates
only when called upon or when the outdoor
conditions are suitable for economizer operation
whereas the traditional approach has 2 full sized fans
operating year round.
These system features can be designed into
the ductwork or incorporated into the unit as
a complete package.
Figure 16 – Normal Mode
Figure 17 – Normal Mode with Glycol Heat recovery
Figure 18 – Purge or Economizer Mode
Table 8 – Exhaust Fan Operation