Specifications

5
The type of facility being designed dictates the
space temperature. Table 1 helps target some
typical conditions. It is critical to understand who
will be using the facility in order to deliver the
conditions most likely to satisfy them.
Pool Type
Air
Temperature, °F
Water
Temperature, °F
Competition 78 to 85 76 to 82
Diving 80 to 85 84 to 88
Elderly Swimmers 84 to 85 85 to 90
Hotel 82 to 85 82 to 86
Physical Therapy 80 to 85 90 to 95
Recreational 82 to 85 80 to 85
Whirlpool/spa 80 to 85 102 to 104
Table 1 – Typical Natatorium Operating
Conditions
Indoor pools are normally maintained between 50
and 60% RH for two reasons:
 Swimmers leaving the water feel chilly at lower
relative humidity levels due to evaporation off the
body and:
 It is considerably more expensive (and
unnecessary) to maintain 40% RH instead of
50% RH.
General Notes:
 Facilities with warmer water temperatures tend to
have warmer space temperatures.
 Physical Therapy facilities will cater to therapist
comfort rather than the patient because they are
generally not in the space for more than an hour,
whereas the therapist is there all day. The
designer should consult local codes. Some
States require a full purge of the room air with
100% outdoor air for every hour of occupancy.
 Elderly swimmers tend to prefer much warmer air
and water temperatures.
Humidity Control: High relative humidity
levels inside a building are well known for their
destructive effects on building structure and can
pose serious health concerns. Buildings with high
humidity levels are prone to condensation problems
that can destroy the building structure. They also
facilitate the growth of mold and mildew, which in
addition to being unsightly, can adversely impact
the air quality. Controlling humidity requires that a
total moisture load be accurately calculated. This
amount of moisture must be removed from the
space at the same rate it is generated to maintain
stable space conditions.
1.1 Packaged mechanical refrigeration
system. By far the most common and popular
method of removing moisture from the space, these
are packaged refrigeration units like those built by
Seresco. The units are designed and developed
specifically for dehumidifying indoor pools.
A major benefit of this approach is that both the
sensible and latent heat is combined with the heat
generated by the compressor’s power consumption
and can be directed to wherever heat may be
required in the natatorium. This process is unique in
the HVAC industry as is uses both the cooling and
heat rejection sides of the refrigeration cycle. The
system can be simultaneously dehumidifying
(cooling) the air and then reheating it (and/or the
pool water) to deliver dehumidified and reheated air
to the space, and warm water to the pool.
How it works. Figure 2 illustrates schematically
how warm humid air passes through the
dehumidifying coil and is cooled to below its dew
point. As a result moisture condenses out of the air.
Depending on the space temperature requirements
the hot gas from the compressor can be used to
reheat the air or reject its heat to an outdoor
condenser. Compressor hot gas can also be used
to heat the pool water
.
Figure 2 Mechanical Refrigeration System.
Typical Operating Conditions:
Air On Evaporator: 84°F, 50% RH
Air Off Evaporator: 50°F
Suction Pressure: 65 PSIG
High Pressure: 220 PSIG
Superheat: 12-15 °F
Pool Water Heat: in 84°F- out 92°F