Buildings are becoming increasingly tightly sealed for energy-saving purposes. This saves on heating costs but requires intelligent ventilation to efficiently ventilate and aerate buildings. Natural ventilation provided by automated windows is a smart solution that significantly improves the indoor climate but uses little energy and requires low investment costs.
People are generally not great at creating sufficient ventilation in buildings
A good indoor climate depends on a number of factors. Temperature and humidity both play key roles, but acoustic and visual aspects also contribute to wellbeing.
But why is typical ventilation often insufficient? Because we take our cues from thermal, acoustic and visual stimuli, but lack sensitivity to air quality. People primarily judge air quality based on bad smells,, yet they get used to these smells the longer they spend in the same rooms and so don’t notice a reduction in air quality.
We only notice poor quality air when it is too late. Efficiency drops and people become sleepy or get headaches – because humans breathing produces excessive concentrations of CO2. The situation is exacerbated by pollutants which can evaporate from furniture or carpets.
Mandatory controlled ventilation
Due to modern, energy-saving construction methods, we work, live and learn in increasingly tightly sealed buildings. The downside: not enough fresh air flows in and humidity, heat and smells are insufficiently extracted.
However, the German Energy Saving Ordinance (EnEV) prescribes that buildings must be constructed in a way which guarantees the minimum exchange of air necessary for the purposes of health and heating. Controlled ventilation is therefore needed in a building which has been constructed in accordance with EnEV.
A mechanical ventilation system is one solution. But who enjoys working or living in a building where you can’t open the windows because of the ventilation system? Many people feel uncomfortable in rooms where the windows are always closed. The alternative to this is controlled, natural ventilation via windows, which automatically draws fresh air directly from outside.
Natural window ventilation based on temperature fluctuations and wind
Natural ventilation – also known as “free” ventilation – exchanges air via, without any mechanical ventilation system. The required airflows are produced by the temperature and pressure differences between the internal and external air alone, and by naturally occurring wind flows.
The intelligent façades themselves create the ventilation. This means that motor-operated windows are controlled by sensor signals, such as for example by weather stations or air quality sensors. Intelligent indoor climate regulation identifies wind strength and direction, external temperatures, precipitation, room temperatures, humidity and CO2 values of the indoor air, and controls the opening and closing of the automated windows accordingly. The window control is completely independent of the user, even when the building is empty.
Natural and energy-efficient
In addition to CO2, classrooms or offices with a large number of people also generate a lot of heat. In the summer, in particular, solar rays often heat the room even more. Natural ventilation can direct unwanted warm air out of the room and let fresh, cool external airflow in. In the cool night-time period, free ventilation provides natural climate control. This naturally produces good air quality, without using any energy to supply and cool the air.
The benefits of natural ventilation with electric window drives
- the healthy and comfortable air quality and temperature guarantee the wellbeing of the room users
- protection of the building substance (mould prevention)
- controlled opening and closing of the window saves energy compared to continuous mechanical (fan-based) ventilation
- simple integration into existing buildings /modernisation properties
Convenient and flexible systems
Intelligently controlled windows ensure natural ventilation, and in contrast to mechanical ventilation systems, the user also has the option of intervening (for example using window buttons located nearby). Acceptance of these types of automated systems is therefore very high.
They are truly convenient: if someone forgets to close a window, windows are closed in a controlled way via the control unit so that no valuable heat is lost, and the security of the building remains guaranteed.
Potential settings and combinations
- convenient ventilation
- night-time back cooling
- gap ventilation
- intermittent ventilation
- fresh air in the morning
- the individual user control function
- weather-dependent safety functions
- combination with smoke and heat installations
Natural ventilation and smoke and heat extraction
Natural smoke and heat extraction installations open windows in the roof or façade in the event of a fire, to direct smoke and hot gases out of a structure. In Germany, they are mandatory when natural smoke extraction is required by the building authorities. This official building regulations requirement applies to special constructions in particular, for example for schools, retail outlets and hospitals.
Automated windows in smoke and heat extraction installations offer daily, natural ventilation as an additional benefit.
Window opening systems with intelligent GEZE drives
GEZE drive systems are available for a diverse range of window shapes, designs and sizes, whether in the ceiling or façade. The range includes electrically-operated chain drives, electric spindle drives and locking drives.
GEZE window drives and locking systems can be directly integrated into the KNX building bus with the GEZE IQ box KNX. This enables versatile and flexible solutions for natural ventilation.
- integration of automated windows into the KNX building bus system
- opening of the windows to any position desired (in %)
- reporting contact of window statuses (open/closed/% ) and drive statuses (cycle number, failures)
- timed ventilation, gap ventilation
- automatic closing and blocking in the event of rain or wind alarm or when the air-conditioning is switched on
- integrated button interface (local/KNX) enables connection to the lower cost vent switch