Zenith Ventilation supply and install all indoor pool ventilation solutions for both residential and commercial aquatic centres. In order to calculate the humidity load on an indoor swimming pool project, you first need to determine the operation conditions.
In doing this, there are a number of factors to take into consideration. Contact Zenith Ventilation to assess the requirements needed.
In consideration of both comfort and budget, the air temperature around a swimming pool should be higher than the water temperature. This minimises evaporation and the dehumidification requirement. However, an increased room temperature will of course impact the heating bill.
In general, it is recommended that the room temperature is set to 2°C higher than the water temperature
When setting the water temperature, the following benchmarks will often be a good starting point.
The relative humidity is an expression of the air’s actual water vapour pressure compared to the water vapour pressure when the air is saturated. It is stated as a percentage, and the set point when managing the operating conditions for a dehumidifier should be an RH value of 50-60%.
You can also choose to operate with a differentiated set point, so that it is low during winter (50 %RH) to avoid condensation problems on cold surfaces, and high during summer (60 %RH) to reduce the operating costs. When the temperature is high during the summer, condensation problems do not occur.
Going above 60 %RH will impact the comfort level negatively and increase the risk of condensation problems and fungal attacks. An RH value any lower than 50 %RH is not appropriate either, since this will increase evaporation leading to greater dehumidification requirements and increased operating costs.
The water content in the outdoor air varies a lot over the year, more or less all over the world. From more than 12 g water/kg air during the summer down to 2 g water/kg air during the winter.
We use the guideline VDI 2089 by The Association of German Engineers (VDI) when setting operating conditions for internal condition, outside condition and amount of outdoor air.
VDI has chosen 9 g water/kg air as the value that characterises outdoor air in Northern Europe and we use this figure in our calculation program DanCalcTool.
However, other values can be used for outdoor air in DanCalcTool, if the values deviate significantly from the Northern European standard.
In addition, VDI 2089 recommends that the absolute water content of the indoor air does not exceed 14.3 g water/kg air (54 %RH with an air temperature of 30°C), if the water content of the outdoor air is less than 9 g water/kg air, which will be the situation during winter.
