Skip links

Using IoT to combat thick air in inner cities.

In many cities, the air poses a high health risk because it contains too much particulate matter and nitrogen oxides. The smart Filter Cubes from MANN+HUMMEL succeeds in reducing the pollutant load of the outside air. An IoT device from optiMEAS controls the demand-oriented, energy-saving operation and provides the connection to the cloud securely.

M+H Filter Cubes with smartMINI

The challenge: The air must improve in inner-city hotspots

Where there is a lot of traffic, along multi-lane Streets, intersections and traffic light areas endanger nitrogen dioxide (NO2) and particulate matterdust particles can damage the health of local residents, passers-by and other road users. Cities all over the world have been working with this problem and are looking for ways, to improve the air and driving bans to prevent it. The focus of Stuttgart was for years, the Neckartor has been a particularly polluted area. The Ludwigsburg Filtration specialist MANN+HUMMEL took took up the issue, and at the beginning of 2018, the the starting signal for a pilot project to dedevelopment of a stationary filter solution for Outside air, sponsored by the Ministry of Transport Baden-Württemberg and supported by the State capital Stuttgart. The new technoThe energy consumption of the newmay reduce the concentration of pollutants. What was wanted was a system that could be remotely controlled and monitored.

The solution: Networked filter cubes with intelligent system architecture

Within two years, the MANN+HUMMEL the "Filter Cube" air filtration system, which effectively removes both fine dust and nitrogen dioxide from the air. As an IoT partner MANN+HUMMEL the optiMEAS company on board again. A year earlier, they had already jointly developed the "Fine dust eater"a mobile filtration solution for use in vehicles. The Filter Cube is a cube with a side length of just under one metre, inside which there is an innovative filter system: a powerful but energy-efficient industrial fan draws in the polluted outside air and forces it through a combi-filter. This specially developed filter medium, which consists of a particle filter and an activated carbon layer with an extra large surface area, absorbs more than 80 percent of the nitrogen dioxide and fine dust from the air.
Up to three of these cubes can be stacked to form a filter column. Several columns are needed to serve an entire street. External sensors record the air quality and important weather data.

The IoT Edge Device smartMINI from optiMEAS, which is installed in the base of the filter column together with the power electronics, serves as a gateway and control unit. The integrated software offers project-specific IoT functions for data acquisition and transmission, GPS, bus interfaces, remote access and other intelligent functions. This enables smartMINI the bidirectional communication between the filter cubes and the cloud server of MANN+HUMMELwhere all plant data is collected, analysed and processed. smartMINI records the operating parameters of up to three Cubes, including the speed, power consumption and temperature of the fans, error messages and operating hours, each enriched with a precise GPS signal. In addition, there is data from a rain sensor integrated into the column. Via MQTT, the IoT device sends the live data to the cloud and, for security, a file with the raw data at longer intervals. In this way, reliable diagnostic data is available, even if the connection to the server was interrupted in the meantime and no live data was transmitted.

In the opposite direction smartMINI the control commands of the cloud dashboard and passes them on to the fans via a Modbus interface. The dashboard analyses all data in summary form and takes into account stored configurations with limit values and specifications as to how the system should behave under certain conditions. For example, the fan switches off automatically when it rains, because air purification is not necessary then. And in the vicinity of residential areas, an automatic timer switches to night operation with reduced speed to reduce noise emissions. Preconfigured performance settings, such as day and night mode, can also be set manually via switches on the dashboard. For service visits to change filters, the columns can be conveniently switched on and off remotely.

The stationary air purifiers are designed for 24/7/365 operation. smartMINI monitors the speed and temperature of the fans and is fail-safe thanks to integrated watchdogs. Software updates are carried out as over-the-air updates during operation and can be easily triggered from the dashboard.

The result:
Demand-driven air purification, reliable and efficient

The Filter Cubes from MANN+HUMMEL offer an effective way to improve the air in hotspots with modern fan and filter technology, intelligent sensor technology and internet-based control technology. Per hour, a filter column consisting of three cubes cleans 14,500 m³ of air. It has been shown that the column is effective within a radius of 15 to 20 metres and significantly reduces pollutant levels there. This is also the case in Stuttgart at the Neckartor street section, where 23 filter columns are installed. The demand-based remote control via smartMINI ensures efficient operation with low energy consumption and ensures that noise protection requirements are reliably met around the clock. Should the connection to the server ever be disrupted, the unit automatically goes into emergency mode with reduced power. Recorded diagnostic data not only create the data basis for further analyses, but also provide detailed information about the current "state of health" of the unit. Problems can thus be detected at an early stage and service calls can be planned well. In the meantime, more than 100 columns not only in Stuttgart and Heilbronn, but also in South Korea, China, India and Brazil ensure better air - everywhere controlled by a smartMINI. The 4G IoT mobile modem used allows worldwide use without hardware adaptations - a national SIM card is sufficient.