Room air disinfection

In the past, the main purpose of installing ventilation systems was to guarantee a certain minimum level of comfort within rooms. Currently, the issue of hygiene is increasingly coming to the fore. As a result, in addition to the requirements for conditioned air, the demands on the cleanliness of ventilation ducts and fittings are also increasing. Hospitals, doctors’ surgeries and swimming pools in particular require regular inspections and cleaning to ensure that they are permanently free of germs, bacteria and moss. There is therefore an increased demand for ventilation systems with the highest possible germ inactivation rate and low cleaning and maintenance requirements.
Another focus is on the feel-good factor within public spaces and places of assembly. A pleasant indoor climate is crucial to the success of salesrooms, restaurants and swimming pools in particular, as fresh, conditioned indoor air increases the well-being and therefore the purchasing behavior of customers. A healthy indoor climate is also essential for hotels, schools and other places of care. However, the comfort of a room also depends on its color scheme. Beyond its decorative contribution, color has a direct influence on people’s behavior and well-being. It has long been known that colors have a calming, relaxing but also stimulating and concentration-enhancing effect. It is therefore not enough for ventilation and air-conditioning systems to simply adapt to the respective design concept. The system, all the shaped elements and their appearance should serve as a design element and support and even improve the desired atmosphere.
In collaboration with Prechtl Lufttechnik GmbH, an irradiation module for inactivating germs for use in ventilation and air conditioning systems was designed and tested in the research project “Development of a design-optimized and germ-reduced ventilation duct system” [Fig. 1].

This was realized as a duct element that can be easily integrated into a system with two filter units for the retention of particles and two UVC emitters (254 nm main emission, no ozone formation). The low-pressure mercury emitters used have a high radiation intensity with doses of approx. 65 J/m², which inactivates 90% or more of common airborne germs. The installed filter units serve as a boundary for the irradiated space and thus provide an obstacle for particles and droplets in the air, so that the microorganisms adsorbed on them are exposed to UVC radiation for longer and thus experience higher irradiation doses.
In duct elements made of galvanized sheet steel, the germ content of the air was reduced by 80% – 90%. In aluminum ducts, 75% – 85% of the microorganisms were inactivated. Tests with irradiation intervals of 1 and 2 hours showed that continuous operation of the UV lamps leads to greater disinfection and also protects the lamps so that their service life is not impaired by too many switch-on and switch-off processes.
Based on the results obtained, a stand-alone device for room air disinfection was developed and tested in addition to the disinfection module for ventilation systems. A new product was thus added to Prechtl’s portfolio. GMBU e.V. is supporting its market launch with various service measures for consulting and training in the field of room air analysis, as well as application-dependent selection and monitoring of UV lamps.

Prechtl-Flyer-UV-AIR-PROTECTOR

Project partners: Prechtl Lufttechnik GmbH ; Innovent e.V. – Technology Development Jena
Duration: 01.08.2018 – 31.07.2020
Funding body: AiF Projekt GmbH on behalf of the BMWK