How do hotels dehumidify their pool rooms

Indoor swimming pool dehumidification systems

Most people feel comfortable in the swimming pool when the room temperature is around 30 degrees Celsius, two to three degrees more than the water temperature.

In addition to warmth, air humidity is an important parameter for well-being. If the air is too humid, it is perceived as muggy.

But that's not the only reason why dehumidifying swimming pools makes sense: Excessive humidity can also affect the building fabric, because spores and mold would find a good breeding ground in a warm, humid climate.

Seen in this way, dehumidification is a level of comfort that benefits people and masonry at the same time.

When planning the swimming pool, you should therefore think about the type and installation of dehumidification. There are different ways of dealing with high humidity.

Ventilation is a simple but cost-intensive option in the long run: fans transport moist air outside and fresh air into the hall.

High energy losses occur, particularly in the transition and winter periods, because heat is carried away with the air in the hall. Even with heat recovery, ventilation requires significantly more energy than dehumidification in recirculation mode, which is common today.

This is achieved by chest units that take up little space and are equipped with energy recovery systems or heat pumps.

This type of dehumidification saves up to 60 percent of energy compared to simple air exchange.

Dehumidifiers for circulating air operation are dimensioned for private use in such a way that they ensure the desired humidity on a daily average. Swimming pool covers help to keep evaporation to a minimum during rest periods.

Floor standing units like the GEA-Fricostar F800 are compact and easy to install.

An example of dehumidifying devices is the GEA Fricostar F800 from GEA Happel Klimatechnik GmbH, Herne. It is particularly suitable for private swimming pools with a pool area of ​​up to 50 square meters and extracts the moisture from the indoor air with a scroll compressor.

It sucks in the air and cools it to below the dew point, at which the air no longer absorbs moisture. As a result, the moisture condenses on the cold surfaces of the evaporator and is then discharged.

Heat recovery avoids energy losses and temperature controls the air before it flows back into the hall. This device works in the application range of 22 degrees Celsius / 40 percent rel. F. up to 36 degrees Celsius / 60 percent rel. F.

For the design according to the VDI guideline, the typical values ​​are 28 degrees Celsius water at 30 degrees Celsius air and 54 percent rel. F. In the standard version, the dehumidifying device described as an example can provide up to 3.4 kg / h of dehumidification performance.

The optionally available pool water condenser increases the output - due to the larger condensation surface - by 0.5 kg / h. This leads to a higher degree of efficiency.

The recovered heat can be fed into the pool water, which relieves the static heating.

Owners of smaller pools (up to 20 or 25 square meters) do not even need additional energy to keep the water temperature constant; additional heat is only required after the water has been changed.

In larger pools, the pool water condenser ensures that the power to be supplied by a heating system to stabilize the water temperature is up to 2.9 kW lower.

Another advantage of a pool water condenser is that the swimming pool does not overheat quickly when the air is circulated. In summer in particular, many find it pleasant when the warmth benefits the water instead of heating the indoor air.

On the one hand, additional expenses amounting to approx. 400 euros are noticeable as a plus in comfort, on the other hand, the investment in the accessories pays for itself through the cost savings in the static heating.

Depending on the operating conditions and heating system, the additional costs for the pool water condenser are offset by the lower operating costs after just two years.

Services at a glance

A heat exchanger, available on request, allows the dehumidifier to be operated with outside air. A few kilowatts of heating power is sufficient even in winter to heat the fresh air to the required level.

In summer, fresh air can help improve the air in the swimming pool. This is particularly interesting for those who only have limited or no ventilation alternatives, for example because the swimming pool is in the basement and has no window facade.

Both components - the pool water condenser and the additional heating - can be ordered individually or together as accessories from GEA Happel Klimatechnik, for example.

If you prefer to set up your dehumidification system outside the swimming pool in a frost-free neighboring room, you can order the F800 without a housing, but with accessories for rear wall mounting.

On the swimming pool side, only one air inlet and one outlet reveal where the device is located. Architects and builders have additional alternatives when designing the swimming pool.

It is also possible to connect two dehumidifiers in parallel. This allows them to be used in larger, private pools, for example, or increases the dehumidification performance in order to take account of evaporation through whirlpools or countercurrent systems.

The dehumidification performance required for the respective swimming pool can be determined using design diagrams (see graphic); Whirlpools or countercurrent systems are included in the calculation with the help of VDI guideline 2089.

This article appeared in issue 35 of pool magazine.