LEARNING SUCCESS THROUGH VENTILATION – A MATTER OF COURSE IN MODERN SCHOOLS

But to what extent is learning success influenced at all, and which factors play a role?

How important good indoor air quality is has been known for a long time. In this context, schools in particular moved into the focus of researchers. The Bavarian chemist Max Pettenkofer is considered a pioneer of Indoor Air Quality (IAQ). Already in the 19th century, he measured the carbon dioxide content of the air in schools in several experiments and compared it with the olfactory impression of the room users. The Pettenkofer value of 1,000 ppm carbon dioxide content is named after him.

It is also astonishing that already in 1884, under Pettenkofer’s influence, Paragraph 9 of a school authority decree of the royal government of the Upper Palatinate stipulated that “for the purpose of achieving the necessary air renewal, ventilation chimneys are to be constructed. These must have two openings: one near the floor, the other near the ceiling.” If you will, that was the birth of ventilation systems in schools.

Today’s scientists, such as the Danish professor Pavel Wargocki, have confirmed Pettenkofer’s statements. Wargocki has found that indoor air quality significantly influences school performance. Measurements in two comparable classrooms showed that when the outdoor air rate was doubled, the speed at which arithmetic problems were solved increased by up to 14 percent on average. Numerous further studies prove that as little as 21 m³/h of fresh outdoor air per person must be available in order for concentration to remain at 100 percent. Raising it to 30 m³/h per person increases concentration by a few more percentage points.

According to current knowledge, there is therefore no longer any doubt that better indoor air quality can improve performance and well-being. On the basis of all these findings, Danish building regulations now prescribe a statutory minimum ventilation rate. For practice, this means that in the case of new construction or renovation of a school, mechanical ventilation systems are generally installed.

Renovation of the Paul-Spiegel-Vocational College in Warendorf

This argument alone convinces the district of Warendorf to equip the Paul-Spiegel-Vocational College with ventilation systems. The Paul-Spiegel-Vocational College goes back to the craftsmen’s continuing education school from the year 1856 and has steadily developed further over many decades. Today it offers a diverse range of part-time or full-time courses. Pupils at the Paul-Spiegel-Vocational College can obtain many different school and vocational qualifications; numerous projects and a high share of practical experience provide orientation and increase the chances of young people to gain a foothold in their desired profession.

The construction project is a renovation of the existing building in several construction phases. During the planning phase, decentralized ventilation units of the series X-CUBE SCHOOLAIR-V (vertical parapet ventilation unit) from TROX emerged, which could easily be integrated into the existing building due to their small space requirement.

Technology for optimal indoor air quality

For this purpose, a narrow window element was replaced with an opaque element for air conduction, the existing parapet was adapted to the unit height, and finally a covering matching the room concept was chosen. All units were each placed half on the parapet and half on a substructure and connected to electricity and the water-side supply. Master and slave units are connected with a patch cable for internal communication. In addition, the room control unit is connected to the master units.

With a nominal air volume flow of 320 m³/h, the units provide sufficient fresh air for maximum learning success. Equipped with an outdoor air filter of filter class ePM1 65%, the units ensure that fresh air free of pollutants enters the classroom. Each room was equipped with two units connected in a master-slave configuration. Optimal indoor air quality is ensured by integrated VOC sensors that continuously monitor the indoor air. Depending on the threshold values specially adapted for this project, the outdoor air volume is adjusted. If the indoor air quality is in the optimal range, the units switch to secondary air operation.

Energy-efficient temperature control

But not only good air, also the temperature plays a decisive role. Therefore, controlling the room temperature is another main task of the ventilation units. For this purpose, air/water heat exchangers are located in the units, which heat or cool the supply air according to the requirement for room temperature. The room temperature is measured in the room control unit, which is connected to the master units. The user can also make their own settings here.

To increase energy efficiency, the units are equipped with a heat recovery system that reduces the water-side output to a minimum. Of course, the heat recovery unit can be bypassed, for example to allow night cooling in summer.

Convinced by the concept and the positive experiences of the first phases, all further construction phases were carried out in the same way. Since years sometimes lay between the phases and the technologies used by TROX were constantly further developed, devices of the type X-CUBE SCHOOLAIR-V-HV could now be used. With this new device type, decentralized ventilation units are now available which, with the same acoustics, deliver about 50 percent more fresh air and further improve indoor air quality. In addition, the units have a rotary heat exchanger, which combines many advantages: on the one hand, the heat recovery rate is particularly high, which improves energy efficiency; on the other hand, a rotor can be used all year round. Thus, maintaining the heating load for bypass operation in the event of icing is no longer necessary. As a result, the heating system can be dimensioned smaller.

A very special advantage arises from the functional principle: the water contained in the exhaust air condenses in winter and is absorbed by the supply air. This positively influences indoor air humidity and contributes to well-being. The integrated control adjusts the heat recovery rate variably, so that the supply air temperature is already reached after the rotary heat exchanger and the use of the heating/cooling coils is further minimized.

Individually designed control

As diverse as the offerings of this school are, so are the control options of the units. Via individual time programs, the units adapt effortlessly to user behavior. Individual settings can be made via room control units. Before delivery, project-specific features are discussed and stored as parameters in the software. In this way, the school receives exactly the solution that the district of Warendorf and, in particular, the teachers and learners had in mind. At modern schools, learning success thus also arises through ventilation – and that quite naturally.

TROX is a global leader in the development, manufacture, and distribution of components, devices, and systems for ventilation and air conditioning in rooms. With 34 subsidiaries in 29 countries on five continents, 20 production facilities, and additional importers and representatives, the company is present in more than 70 countries. The TROX GROUP currently generates a turnover of approximately 600 million euros worldwide with around 4,600 employees.