Information below is currently being reviewed for content and accuracy, please be advised.

Swimming Pools

Modeling equipment in Building energy Simulation programs

Notes on Swimming Pools (some information below is in conflict)

Evaporation of an indoor swimming pool makes up 70% of heating requirements
ASHRAE 90.1 2004 does have pool heater efficiency requirements at around 78% COP with industry best practices at close to 89%- 94% COP.
ASHRAE 90.1 2004 requires pool covers for pools above 90 degrees F. (with an exception to solar heated pools)
Outdoor pools are seldom to never heated throughout winter, instead a pool heater is often used to extend operating hours of the pool to include part of the swing months.
US Navy in its "Manual of Preventative Medicine" has a series of important things to note about pool temperature and air temperatures in natatoriums (rooms containing a pool).

"Water Temperature. The water temperature in swimming pools should be maintained between 65°F-82°F (18.3°C-27.8°C). (1) Outdoor pools feel warmer than indoor pools of the same temperature. Bathers accept water temperatures of 65°F-78°F (18.3°C- 25.6°C) in outdoor pools more readily than in indoor pools. See NAVFAC DM-37.1 for guidance on outdoor pool heating."
"Water temperatures of indoor pools should vary according to the use or purpose of the pool. Pools used exclusively for competition should be held between 76°F to 78°F (24.4°C-25.6°C). Pools used exclusively for recreational purposes should be held between 78°-82°F (25.6 °C–27.8ºC). A compromise in water temperature may be necessary between competitive and recreational needs for multi-use pools."
"Air Temperature. In winter, the air temperature in indoor pool facilities should be kept approximately 3°F higher than the pool water temperature, while in summer, 8°F above is satisfactory. Bather comfort is affected by air temperature, air movement, and humidity. Bathers feel chilled when there is rapid air movement and low humidity, and if the air temperature is quite high, e.g., 90°F (32°C). Under these conditions, the rapid evaporation of water from the skin will make a bather feel cold. Humidity in the 75 to 85 percent range is effective for bather comfort and for reducing serious problems with equipment due to condensation."

Indoor pools cost more in energy use than outdoor pools due to ventilation requirements of occupied spaces. (this is assuming the normal short operation season of outdoor swimming pools)
Some swimming pool heaters can be sized not from the load, but from the minimum number of days required for start up. This start up from utility service temperature can be tremendous.

2 to 7 days can be a common start up time.
Very large pools sometimes have one "start up" heater used 1-2 times a year, and one "maintenance" heater used commonly.

Pools are cleaned and water changed 1-2 times a year depending on policies, seasons, use, etc.
A typical pool (indoor and outdoor) looses 1- 1/2 inches of water a week to evaporation
Wind plays a very significant impact on outdoor pool energy, a 7 mph wind increases pool energy use by 300%

Simulation programs that contain a working feature of modeling this aspect of a building:

eQuest -eQuest does not have a specific tool for modeling indoor swimming pools. The easiest way to model a swimming pool in eQuest is to:

Place a direct load on the fuel meter corresponding to the estimated yearly energy use of heating the water of the indoor/outdoor pool. (for an estimated value of fuel energy use see below)
For indoor pools, in the natatorium (pool room) space place a process load (expressed to no fuel meter) with a high latent heat gain to the room. (for the amount of this process load, calculate the "heat loss from evaporation" = latent heat gain. To account for the amount of heat conveyed to the room through radiation, estimated it using tools listed below and apply it to the space as a simplified sensible gain.
Wall, floor, and ceiling constructions of indoor pool rooms adjacent to conditioned spaces may have special vapor and insulating constructions.

Non-interactive Simulation tools

Hand Calculation

Common methods of estimating energy use of a pool is to assume a degree temperature loss of the pool per day if the heater was not on.

1-2 Degree F loss of the entire volume of the pool is one commonly estimated amount

Industry Links

Swimming pools