Specifications

20
Natatorium DesigN maNual
The mechanical refrigeration system approach to
controlling the environment in a pool is a unique use of
the refrigeration system. The evaporator controls the
humidity while simultaneously the compressor hot gas
can be used to heat the pool water and/or room air.
Traditional air conditioning systems merely send the
compressor hot gas outdoors to a condenser or cooling
tower and do not tap into this heat source.
Adding the pool water heating option to your
dehumidifier typically has a payback of less than
one year.
Table 5 shows the annual contribution towards water
heating from the dehumidifier while operating in cooling
mode. A pool with a 50 lb/hr evaporation rate and
cooling season of 2000 hours would realize an annual
savings of $2,350 if the primary source of pool water
heating was an electric heater.
Calculations based on: 1000 Btu/lb latent heat of
vaporization. Gas: $0.60 per 100,000 Btu, efficiency =
75%. Electricity: 8¢ per kWh
Most pools require an auxiliary pool water heater. When
the Seresco system is not able to provide full water
heating, it can control the auxilliary heater.
Space Heating
As with every other room being designed, the cooling
and heating load calculations should be done for the
natatorium. That is the only way to ensure the specific
heating and cooling requirements are met. The room
air temperature of an indoor pool facility is generally
10-15 °F warmer than a typical occupied space so the
heating requirement per square foot of a natatorium will
be considerably higher than a traditional room.
• Outdoor air must be included in load calculations as it
often represents up to 50% of the heating load.
Space Cooling
Most patrons prefer buildings with year round
temperature control. Even though the space is generally
10-15 °F warmer than a typical room, most patrons
would find it objectionable to be in a space that has no
cooling at all.
Space cooling is a free byproduct from packaged
dehumidifiers and chilled water systems. Providing year
round temperature and humidity control can be provided
by these systems. These systems dehumidify by cooling
the air below its dew point and condensing moisture at
the cooling coil. If the cooling load exceeds the standard
output of a dehumidification unit, a larger unit with
compressor staging is often specified.
Packaged Refrigeration or Chilled Water dehumidifiers
provide summertime space comfort with no additional
operating cost to the owner.
Outdoor Air, Exhaust Air
and Energy Recovery
Outdoor ventilation air is essential for maintaining good
IAQ in the pool and is a code requirement. The natatorium
needs to be maintained at a slight negative air pressure,
so warm “energy rich” air needs to be exhausted.
Outdoor air must be conditioned. It must be cooled and
dehumidified in the summer and heated in the winter. In
northern regions outdoor air has the biggest impact in
winter where it reduces the space relative humidity levels
and represents a significant portion of the natatorium’s
heating requirement. In southern regions the outdoor air
Table 5 – Annual Water Heating Savings from Pool Heating Option