What is the best way to heat the air in the pool hall and the water in the swimming pool?

Many people do not understand that the air in an indoor swimming pool hall is heated by the heat that comes off the water by evaporation.

As a consequence, the air in an indoor pool hall is full of water vapour (ie. the himidity is very high). If the humidity level is not controlled, condensation will occur and leave every surface in the pool hall running with condensation.

This is a complex process and in the past it was very difficult to control the environmental conditions in a pool hall. But now - thanks to modern Air Handling Units - the air and water temperatures and humidity levels are controlled at the touch of a button.

Modern AHU's are extremely economic to operate because they carry out the following on a continuous basis:

• Remove stale hot humid air from the pool hall and extract the heat energy from it, thus maintaining the humidity at the level set on the control panel (normally about 60%)
• Discharge the stale air into the atmosphere, take in fresh air and heat it using the energy extracted from the stale air and more heat energy as required to the temperature set on the control panel.
• Maintain the pool water temperature at the level set on the control panel by measuring it's temperature and adding the heat energy required.

Outside the winter months, the cheapest way to provide the energy required to heat the pool water to about 29 / 30 degrees C (the temperature that most people will find comfortable) is an air source heat pump (ASHP).

For about 9 months of the year the ASHP will provide about 4 or 5 times the energy required to run it. It is theoretically possible to provide heating throughout the year with high output ASHP's but the capital cost of such equipment is very high.

So in most modern pool installations the heat input in the winter months is provided by a high efficiency gas condensing boiler that provides the heat input directly to the AHU.