Research to Business

Aerobuster – Rendering viruses harmless in classrooms with air sterilization

Prof. Horst Hahn and an interdisciplinary team of researchers want to stem the spread of corona and other viral diseases with a cost-effective and versatile air sterilizer. The developed air purification system makes virus and bacteria-loaded aerosols in indoor spaces, such as classrooms, medical practices and restaurants, inactive.

Student wears a mouth and nose protector in the classroom. Aerobusters could significantly reduce the risk of infection in classrooms. The continuous disinfection of the ambient air reduces the risk of infection and thus contributes significantly to breaking possible infection chains. (Picture: Alexandra_Koch / pixabay.com)
Aerobuster could significantly reduce the risk of infection in classrooms and other places. The continuous disinfection of the ambient air reduces the risk of infection and thus contributes significantly to the interruption of possible infection chains. (Picture: Alexandra_Koch / pixabay.com)
Dr. Thomas Blank, Prof. Horst Hahn, Dr. Jochen Kriegseis and Martin Limbach with the Aerobuster. The compact air sterilizer is the size of a standard lamp and effectively frees interiors from corona viruses and other pathogens. (Picture: Markus Breig / KIT)

Over 20,000 new infections per day in Germany - The latest corona infection figures are causing great uncertainty and fear of infection with SARS-Cov2 viruses in the entire population. The second wave of the pandemic is in full swing, aided by the autumn slump. Effective and safe containment measures are still lacking, so that prevention strategies and contact restrictions have been the primary means of containment. The school system as well as cultural, recreational and gastronomic facilities suffer most from the restrictions in force. In order to effectively reduce the transmission of infections indoors, Professor Horst Hahn from the Institute of Nanotechnology (INT) and other resourceful scientists from KIT have invented a novel air sterilizer. "Technical solutions for infection protection make an important contribution so that drastic restrictions of public life could be avoided," Hahn is convinced. Together with Dr. Thomas Blank from the Institute for Process Data Processing and Electronics (IPE) and Dr.-Ing. Jochen Kriegseis from the Institute for Fluid Mechanics (ISTM), he developed the aerobuster.

 

Infectious aerosols

In the meantime, it has been proven that infection with the corona virus does not only occur via the so-called droplet and smear infection, but that contaminated, virus-laden aerosols play an equally decisive role in the transmission of the COVID-19 pathogen. The tiny aerosol particles are exhaled unnoticed by humans or expelled when they speak, sneeze or cough. Due to their small size and mass, they are airborne and can remain suspended in rooms for up to several hours, depending on environmental conditions. "The project simulated the dispersion of human aerosols in a classroom as an example. The calculations impressively show how high the aerosol concentration and dispersion in the room is after only 15 minutes," emphasizes Dr. Kriegseis. The simulations were implemented with the help of the Institute of Thermal Energy Engineering and Safety (ITES) and the Gasflow software. They also show what effect the air purifier would have: Aerobuster significantly reduces the risk of infection through continuous disinfection/sterilization of the room air.

Aerobuster hunts health endangering aerosols

In contrast to existing air filters, the Aerobuster does not collect pathogens in mechanical filters and thus prevents them from floating. Rather, the Aerobuster was developed to eliminate them. "Common filter solutions pose a residual risk for maintenance personnel at the latest when the filter components are replaced. We treat the air flowing through, which carries the potentially harmful aerosols, with proven disinfection agents and render viruses and bacteria harmless, so that there is no longer any infectiousness," Prof. Hahn makes clear.

Inside the Aerobuster, the aerosol containing air is sterilized in two steps: The sucked-in air is dried by means of a heating element (orange) and irradiated with ultraviolet UV-C light (pink). (Picture: Institute of Nanotechnology / KIT)

Visually, the protoype of the Aerobuster is reminiscent of a heating mushroom. But there is more than hot air inside: In a tubular housing, the fan, special heating element and UV-C source are connected in series to form a mobile virus inactivator. The ambient air is sucked in by the fan and passes through the two disinfection steps with low flow resistance. First, the aerosols are dried under the influence of heat and then the aerosol-bearing viruses and bacteria are inactivated with ultraviolet radiation. The uniform and complete heating of the air that is sucked through is decisive for the effectiveness of the thermal inactivation of the virus-laden aerosols. The optimal design of temperature and UV light was experimentally investigated during the product development. The sterilized air, in which up to 99.8% of the viruses are demonstrably inactive, escapes back into the room air and thus no longer poses a danger to the people in the room.

 

Making interiors virus-safe

It is advantageous if several devices are strategically distributed in the room to capture potentially contaminated aerosols at the shortest distance. Whether as a wall element, on a stand or as a tabletop unit - the technology can be implemented in a wide variety of ways. Hahn adds: "With simulation calculations, the distribution of aerosols can be calculated for all room geometries with different furniture, in order to determine the optimal placement and number of aerobusters, so that the most effective protection against infection for people can be guaranteed. In combination with confining plexiglass walls, the concentration of active viruses in the room air can be drastically reduced. "When using the space-saving aerobuster, there is no high noise pollution and the waste heat can be used to support the heating. Therefore, the air purifier can be used in any interior rooms during normal operation where large groups of people are present," says Dr. Blank.

Compared to commercially available air purifiers, the Aerobuster would be much cheaper to produce and is also highly variable. In the size of a standard lamp, the compact Aerobuster could contribute to infection protection in countless areas: from classrooms, lecture halls, seminar and office rooms, doctors' practices, hospitals, nursing and old people's homes to cultural meeting places and leisure facilities such as fitness studios. Restaurants and hotels would also benefit from the air purifier, which could create a safe environment for their guests.

 

From the idea to the product

This range of applications shows how much potential a cost-effective, space-saving and flexibly mountable solution for infection protection has. The developers of the Aerobuster are particularly concerned about the thousands of school children and caterers whose existence is threatened. "Our motivation is not the possible turnover from the sale of the device, but we want to contribute something to the social task", emphasizes the initiator Hahn. For the inventors, the time of the lockdown meant not only "slowing down", but the situation sparked creativity, voluntary commitment and joint creative energy.

From the first idea in spring 2020, several prototypes of the virus inactivator were built and validated within a very short time with the expertise of all KIT participants. The Institute of Meteorology and Climate Research (IMK) and the Institute of Functional Interfaces (IFG) of KIT were also involved in the scientific investigation and technical development. To validate his idea, Prof. Hahn also sought contact with well-known/leading virologists and was confirmed in his project.

 

Development partner wanted

"There is an urgency to do something to protect people. With the right industrial partner and the support of important multipliers at the political level, Aerobuster can make an important contribution to the management of the pandemic. I would hope that the new air sterilizer will soon be used in many rooms so that people can come together again". Even after the end of the corona pandemic, the device from KIT would still be a solution with a future: for cold and flu viruses and other infectious viral pathogens.

Contact

comments about this article

No comments

Write a comment

* These fields are required

Bilder v.o.n.u: Alexandra_Koch / pixabay.com Markus Breig / KIT Institute of Nanotechnology / KIT

Remember offer

No offers listed yet

This site uses third-party website tracking technologies to provide its services. I agree to this and can revoke or change my consent at any time with effect for the future.

Settings Refuse AcceptLegal NoticePrivacy Policy