When the young foot­ballers of the DFB head to the changing rooms with red faces after two hours of inten­sive training, very few of them will be thinking about the subse­quent tactics session in the video room. First they have to accli­ma­tize and take deep breaths before being able to analyze their next oppo­nent.

Accel­er­ating this “cool down” requires a good team envi­ron­ment, of course. But the right indoor climate is also impor­tant. After all, a cool head and plenty of oxygen are best for discussing tactics. It is a good thing that the DFB has installed venti­lation systems made by NOVA Appa­rate GmbH in its new foot­ball academy. They supply the entire building complex with suffi­cient fresh air and regu­late the temper­a­ture and humidity. The academy boasts a total of 22 AHUs, located every­where from the seminar rooms, fitness rooms, offices and changing rooms through to the press confer­ence hall and athlete house with its 33 rooms.

Natural cooling with water

Ka2O tech­nology – a cooling method based on indi­rect evap­o­ra­tion cooling – is what makes the AHUs used so special. The used air is taken in from the inte­rior and moist­ened with small spray nozzles. The water evap­o­rates and extracts heat from the exhaust air. This occurs in the Ka2O counter-current heat exchangers, where the warm external air drawn in is cooled down by the cold exhaust air without mixing with it. Finally, the outside air is filtered and fed into the inte­rior.

The academy boasts a total of 22 AHUs. (Photo | DFB/Thomas Böcker)

They are located every­where from the press confer­ence hall … (Photo | DFB/Thomas Böcker)

… to the changing rooms … (Photo | DFB/Thomas Böcker)

… and fitness rooms … (Photo | DFB/Thomas Böcker)

… to the lobby. (Photo | DFB/Thomas Böcker)

Compared to classic refrig­er­a­tion machines, the AHUs completely dispense with chem­ical refrig­er­ants or mechan­ical cooling. This makes evap­o­ra­tive cooling partic­u­larly envi­ron­men­tally friendly. After all, it can make do with nothing other than water and a bit of elec­trical power for the water pumps and fans. As a result, the AHUs in the DFB academy are extremely energy-effi­cient and almost completely CO2-neutral. The DFB places great value on this, which shows that more and more compa­nies are using Ka2O tech­nology in order to reduce their carbon foot­print.

“We were so impressed by the envi­ron­mental creden­tials of the evap­o­ra­tion cooling concept, that we decided to use the AHUs from NOVA Appa­rate GmbH for the new foot­ball academy.”

Winfried Naß, Tech­nical Project Manager – Deutscher Fußball-Bund e.V

The only disad­van­tage of evap­o­ra­tion cooling so far has been the limited cooling level – a maximum of 12 Kelvin. However, this problem has been solved with the inno­v­a­tive Ka2O tech­nology from NOVA. The trick is: instead of using a single large heat exchanger, many small heat exchangers are combined in modular form. In addi­tion, the module surfaces through which the old room air is drawn in are sprayed directly with water. This produces a contin­uous water film across a number of small surfaces and an overall cooling effect of the outside air of up to 20 Kelvin. TÜV Süd, a German tech­nical service orga­ni­za­tion, has confirmed this.

But how does the cooled air then get into the inte­rior? This is where RadiPac centrifugal fans from ebm-papst come into play. They have a very robust, low-vibra­tion high-perfor­mance impeller that can with­stand high back pres­sures. The Radi­Pacs are also equipped with Green­Tech EC motors. This means that they have a partic­u­larly high level of effi­ciency with low power require­ments. This makes RadiPac fans perfect for use in AHUs from NOVA. Firstly, due to the back pres­sures gener­ated by the heat exchange. Secondly, because of the envi­ron­men­tally friendly cooling concept behind Ka2O tech­nology.

Farewell aerosols

In addi­tion to energy effi­ciency and low CO2 emis­sions, the quality of the distrib­uted air has also been an impor­tant topic. After all, poor or incor­rect venti­lation increases the risk of infec­tion, for example with COVID-19. But the AHUs from NOVA also excel in this regard, as they only use fresh air from outside. This means that the air indoors is contin­u­ously diluted and aerosols consid­er­ably reduced. This was an essen­tial factor for the DFB, and already state of the art for NOVA even before the pandemic.

Since its at the end of 2021, the foot­ball academy provides an ideal, safe working climate for its 428 employees. And the young German foot­ballers are now able to cool down more quickly after their hot and tire­some training sessions – without having to reach for the ice bucket.