Specifications

19
ENERGY CONSUMPTION CONSIDERATIONS
Energy consumption and performance implications
based on the owner’s choice of operating conditions
and building envelope should be discussed in order to
ensure there are no surprises. An all glass structure, for
example, is going to be expensive to heat and difficult to
keep condensation free in a northern climate.
A natatorium has 5 major areas of energy consumption:
• Pool water heating
• Dehumidification
• Space heating in winter
• Space Cooling in summer
• Outdoor air heating and cooling
Operating Conditions
Pool water heating and evaporation rates are always
interrelated. Every pound of moisture evaporated to the
space is a load to be dehumidified and it also represents
heat lost by the pool water. 90% of a pool’s annual
water heating cost is due to pool water evaporation
losses. Every pound of moisture evaporated represents
~1000 Btu of heat lost from the pool water body and
unless a pool is covered, they lose that heat (evaporate
moisture) 24/7.
• The warmer the pool water, the higher the
evaporation rate.
• The lower the space relative humidity level, the higher
the evaporation rate.
• The lower the room temperature (dew point), the
higher the evaporation rate.
At the same water temperature a pool in a room at 78°F
50% RH will evaporate almost 35% more than that same
pool in an 85°F 50% RH room.
While the space temperature should be dictated by
the owner based on what satisfies their patrons, is it
useful to be aware of a few guidelines that can help with
energy consumption:
• Maintaining the room air temperature 2°F-4°F above
the pool water temperature (86 degree maximum,
per ASHRAE) will help reduce evaporation. This
reduced evaporation in turn reduces the pool water
heating requirement.
• Do not introduce more outdoor ventilation air than
required by code. In winter the space relative humidity
levels will drop below 50% which increases the
evaporation and pool water heating.
Pool Water Heating Energy Recovery
When using a refrigeration based approach to control
humidity, the dehumidification process captures energy
in the refrigerant at the evaporator coil. The latent
heat component is essentially the pool’s evaporation.
Evaporation represents a significant portion of the
pool’s annual water heating requirements. If this energy
is captured in the refrigerant, why not return it back to
the pool water where it came from? This is free heat
as a byproduct of dehumidifying the air. A Seresco
dehumidifier with the pool water heating option has an
enormous potential for energy savings.
A Seresco dehumidifier with the pool water heating
option will capture and return the energy the pool
water lost through evaporation. This process has an
impressive COP of close to 8!
The use of the pool water heating option
satisfies ASHRAE Energy Standard 90.1,
otherwise a pool cover is required to meet
the standard.
The Seresco refrigeration based unit uses 100% of
the compressor hot gas to heat the pool water and/
or reheat the air. Returning this free energy back
to the pool water or room air greatly reduces the
annual heating costs. During the cooling season the
dehumidifier is capable of providing 100% of the pool’s
water-heating requirement.
Energy Consumption Considerations