In cold climates, outdoor air can have a very low moisture content in the winter. In well-ventilated premises, the relative humidity (RH) under these conditions can be as low as 5-10% RH indoors.
Humans and vegetation emit moisture and, in premises such as offices, schools, etc., there is a good potential to recover the humidity generated.
By equipping the air handling unit with a sorption treated rotary heat exchanger, a significant part of the generated humidity can be recovered, resulting in a more comfortable and healthy indoor climate.
Sorption rotors are best-in-class for humidity recoverySorption treated rotors have a humidity recovery efficiency of up to 70-90%. In cold weather, the sorption rotor recovers moisture in the extract air and returns it to the supply air, providing a more comfortable indoor climate and reducing the need for defrosting. Sorption rotors are also excellent at recovering cooling; which has a profound impact on both the cooling power demand and energy consumption. All this means that sorption rotors are by far the best option for humidity recovery. In comparison, normal aluminium plate heat exchangers and run-around coil systems cannot recover humidity at all.
Hygrostatic rotor control
For GOLD air handling units with RECOsorptic heat exchangers, there is a function to recover and maintain indoor humidity in an efficient and controlled way, so that a good indoor climate can be achieved. Controlling the speed of the heat exchanger, taking into account the humidity of the room and the outdoor air, allows the optimisation of humidity recovery.
In the winter, a drying function can be activated to avoid temporarily high humidity indoors.
Sometimes extra humidity needs to be added to the room to maintain a good indoor climate. The GOLD air handling unit also has built-in functionality to control an evaporative humidifier or to control a steam humidifier. Depending on the location of the humidity sensor, the humidity can be controlled in the supply air, extract air or in the room. A weekly timer with four time channels makes it possible to switch between two configurable values (%RH). If a steam humidifier is installed and it’s equipped with an electricity meter, the energy consumption can be reported in the GOLD air handling unit’s hand-held terminal and built-in web page.
The importance of correct humidity levels
A KEY ASPECT OF IAQ
The short video to the left explains in general how humidity affects both buildings and human health.
To learn more about the importance of correct humidity levels for an optimal indoor climate, please explore below resourses: