Smart City: Continuous air quality monitoring powered by innovative UPS Solutions

Our success story with VAISALA GmbH

The digitalisation of urban infrastructure is key to enhancing the quality of life in modern Smart Cities. A central pillar of this transformation is the high-resolution monitoring of air quality. To generate comprehensive data, sensors must be precise, durable, and, above all, self-sufficient. A joint project between Vaisala and Bicker Elektronik—using the city of Darmstadt as a prime example—demonstrates how a significant technical hurdle was overcome: the discontinuous power supply provided by street lighting.

The Challenge: Power Only at Night
To achieve the most comprehensive monitoring possible, approximately 40 measurement locations were defined. To avoid the prohibitive costs of laying new underground power cables, the Vaisala AQT530 air quality transmitters were to be installed directly onto existing lamp posts. The problem? These posts only carry a 230 VAC current while the street lights are switched on at night.

However, for valid 24/7 datasets, the system must operate without interruption throughout the day. This necessitated an Uninterruptible Power Supply (UPS) solution that could:

• Withstand extreme temperature fluctuations (-20 to +50 °C).

• Recharge quickly during short summer nights to bridge long daylight hours.

• Operate maintenance-free for a service life of at least 10 years.

The Solution: Intelligent Buffering with LiFePO4 Technology
Bicker Elektronik’s engineers met these requirements with the UPSI-2406IP-38AC, a bespoke outdoor solution housed in a robust IP65-rated aluminium enclosure. The core of the system is built around Lithium Iron Phosphate (LiFePO4) technology.

Technical Highlights:

• AC/DC Conversion & Charging: During the night, the system converts 230 VAC to 24 VDC, powering the sensor while simultaneously charging the high-capacity energy storage.

• Seamless Transition: As soon as the street lights turn off in the morning, a MOSFET switch disconnects the input within microseconds. The energy storage then powers the sensor and gateway uninterrupted throughout the day.

• Longevity & TCO: With up to 6,000 charge cycles and a lifespan exceeding 10 years, the system offers a significant Total Cost of Ownership (TCO) advantage over traditional lead-gel batteries.

• Safety: The LiFePO4 chemistry is exceptionally stable, making thermal runaway virtually impossible even under harsh outdoor conditions.

Conclusion and Benefits
This collaboration resulted in a cost-effective and sustainable solution that bypasses the need for expensive infrastructure upgrades by leveraging existing lighting architecture.

"Thanks to the cooperation with Bicker Elektronik, completely new possibilities have opened up for using our measuring systems autonomously in 24/7 continuous operation." > — Jens Dickau, Sales Manager Road Weather Systems, Vaisala GmbH

This project highlights that the success of Smart City concepts depends not only on advanced sensing technology but also on intelligent, ruggedised power solutions that ensure data remains fluid and reliable.