There are also easy solutions available for indoor air quality problems at schools
Classroom-specific ventilation can be a cost-effective solution for indoor air quality problems at schools.
Classroom and space-specific ventilation is a cost-effective and quick way to improve the indoor air quality at schools and daycare centres. Humidity, carbon dioxide, and smells caused by people can be easily removed by boosting the ventilation. Structural impurities can also be removed by controlled supply and extract air ventilation that does not create underpressure in the rooms.
In a decentralised system, each classroom or space has an independent ventilation unit. This enables the efficiency of ventilation in individual classrooms to be adjusted regardless of the ventilation needs of other classrooms. When the classroom is in use, the efficiency of the ventilation is adjusted according to the need. The ventilation can be turned down when the classroom is unoccupied, such as during free periods, weekends and holidays. However, the ventilation must never be stopped completely, in order to ensure that structural impurities and moisture generated by people are removed from the premises.
Carbon dioxide-based control is an excellent means for the automatic need-based control of ventilation at premises where the number of occupants varies. The carbon dioxide-based control identifies when people enter the premises and enhances the efficiency of the ventilation almost steplessly. This way, the ventilation is not too efficient when there are only a few people present in the classroom, but the efficiency can be increased to make the same room suitable for large groups.
Humidity-based control is the best method for controlling the efficiency of the ventilation in sports facilities of schools and in the bathrooms of daycare centres. The humidity-based control enhances the ventilation automatically during showering or the drying of clothes, until the premises and structures have dried. The self-learning humidity-based control by Vallox adjusts automatically to changes such as the varying humidity levels caused by seasonal changes, and there is no need to change the default values of the ventilation.
At premises where the use of the rooms generates impurities (e.g. arts and hairdressing classrooms), the control should be based on a VOC sensor that reacts to volatile organic compounds, such as solvent vapours, detergents and emissions from materials.
The Vallox humidity, carbon dioxide and VOC sensors are maintenance-free and do not require calibration.
The automatic ventilation control also works outside the regular hours (in the evenings, etc.) or when the use of the premises changes. There is no need to change the settings manually, as the automation recognises the size and activity level of the group and gradually increases the efficiency of the ventilation according to the need, ensuring that the indoor air remains fresh until the end of class. The efficiency of the ventilation is reduced automatically when the premises are unoccupied, which saves energy.
Cost-effective to implement
The ventilation unit can be installed in a sound-attenuated space inside the classroom or in the corridor. The ventilation ducts inside the classroom are relatively short and only the ducts or their enclosures and the terminal devices of ventilation will be visible. No ventilation unit spaces or related ducts and conduits need to be installed on the roof of the school. A decentralised ventilation system is fire safe, as the fire cannot spread from one classroom or floor to another through the duct system.
Decentralised ventilation can also be installed one classroom or floor at a time, allowing renovations without having to close the entire school. A decentralised ventilation system is also an excellent solution when the use of the premises change or when ventilation is installed in extensions or temporary school premises. Installation of an individual ventilation unit does not affect other ventilation units within the building or their use.
A decentralised ventilation system is a reliable and cost-effective solution. As specific rooms for ventilation units and extensive duct networks are not needed, the need for building work remains low, as well as the associated costs. If extract air can be blown out of the classroom through the wall, duct conduits that require a lot of space are not needed between the floors.
The equipment with low power consumption does not usually require changes to the existing wiring either. No water-circulating radiators are needed for heating the supply air in the highly efficient ventilation units, meaning that no connections are needed to the heating system. Sewage is needed for condensing water because the highly efficient heat recovery condenses plenty of water, even from the dry extract air of the classroom.
The decentralised ventilation system is easy to design, as the same blueprint can often be used in each classroom. Ventilation units are also available in various sizes for different-sized premises. The setup and the adjustment of airflows is quick and easy as the system is so simple.
Cost-effective and easy to use
Space-specific ventilation creates savings in electricity consumption. Not all premises are usually fully occupied at the same time, so it would be a waste of money and energy to always have the ventilation at full speed in the entire building. Some of the classrooms might be in use late in the evening, early in the morning, or even during weekends and holidays, when centralised time-controlled ventilation does not serve the users. Automatically controlled decentralised ventilation only boosts the ventilation when and where it is needed.
The electricity consumption of the energy-efficient DC fans of the Vallox ventilation units is low and the short ducts reduce the need for fan power. When the classroom is empty, the electricity consumption of the fans also decreases as the efficiency of the ventilation is reduced.
Efficient heat recovery heats the supply air, using the heat recovered from the extract air. The modern and highly efficient Vallox ventilation units heat the supply air almost throughout the year to over +17°C with the free energy recovered from the extract air. Very little additional heating of the supply air is needed, and no modifications are needed to the heating system.
Result: a good indoor climate
One sign of good ventilation is that you do not notice it. The lack of a draught is an essential part of a good indoor climate. A ventilation unit equipped with heat recovery heats the supply air in winter, making it pleasantly warm. Heated supply air and correctly implemented air distribution helps to avoid unpleasant draught. In warm weather, the bypass automation of the heat recovery cell carries cooler outdoor air into the building. Ventilation equipped with automation is always running at adequate efficiency, and the ventilation is not too strong or the premises draughty, even when the room is occupied only by a small group.
All Vallox ventilation units have original filters that are certified according to EN 779 (F7)/ISO 16890 (ISO ePM1 50%). They efficiently filter impurities, such as pollen and soot, from the outdoor air. Impurities, dust and humidity from people or structures are removed from the premises by means of ventilation. Vallox ventilation units always have a plate heat exchanger that does not allow humidity or smells to migrate back into the building in the supply air. Also, impurities cannot spread from one space to another through the ventilation system, as each space has its own ventilation system.
Quiet ventilation requires that the ventilation unit and the duct network are correctly dimensioned, the sound attenuation of the system is adequate and, where necessary, the penetrations of the ventilation unit and the ducts are soundproofed in the classroom. When the number of pupils in the classroom is small, the ventilation operates at a low speed and is almost silent. When the classroom is full, the absorbent surface formed by the people reduces the noise and the noise generated by a correctly implemented ventilation system is not disturbing.
Advanced automation
All Vallox MV models can be controlled automatically with humidity, carbon dioxide and VOC sensors. The almost stepless adjustment ensures that a suitable and unnoticeable ventilation level is available for every situation.
The Vallox MV models can be connected to the Modbus bus without a separate adapter. The MV models can also be controlled on a computer, a mobile device or the Internet by using a LAN network. The unit can also be registered with the free MyVallox Cloud service. The fan speed can be controlled through an analogue (0-10 VDC) or digital input (0/24 V), and notifications can be submitted to building automation from the error relay where required. Week clock control, summer/winter automation, automatic night-time cooling, boost switch and maintenance reminder are standard functions in the MV models.
