Mühlhausen Municipal Library
In addition to books and digital media, the municipal library also hosts regular cultural events. Thanks to the smart ventilation control system, en:air from Kieback&Peter, the air quality is now automatically maintained in the optimum range no matter the number of visitors, which not only increases comfort but also optimizes the storage conditions for the books. © Tino Sieland

The “Stadtbibliothek Mühlhausen” is one of the oldest public libraries in the federal state of Thuringia and since 2004, it has been located in a very special building – the medieval Jakobikirche (St. James' Church), which was deconsecrated around 200 years ago. Visitors to the library can not only borrow books and electronic media, but can also attend readings by authors, lectures and concerts. This means that the church building, which was first mentioned in historical records in 1296, continues to live on as a popular meeting place for people in the region. In addition to top-class culture, the historic building also boasts state-of-the-art, climate-friendly efficiency technology: In 2021, Kieback&Peter made the entire ventilation system fit for a bright, energy-efficient future with the demand-driven automation control en:air, thereby achieving considerable savings with heat and electricity consumption in the double-digit percentage range.

Better air quality, greater comfort – and climate protection

The Mühlhausen municipal library is located in the Gothic nave of St. James' Church, which was first mentioned in 1296. Since 2021, energy-saving automation from Kieback&Peter has ensured optimal air quality in the listed building – reducing consumption in the double-digit percentage range. ǀ © Kieback&Peter

“The old ventilation control system in the church only had two fixed output levels, making it a bit of a dinosaur in terms of efficiency,” explains project manager Christian Oberthür from the Kieback&Peter subsidiary in Erfurt. “The municipal library covers the entire nave over several floors, everything is open. The negative side effects included, for example, unpleasant temperature stratification and poor air quality when there were high numbers of visitors.” The town of Mühlhausen wanted to change this and commissioned Kieback&Peter to help: “Our solution was intended to bring about three specific benefits in particular: firstly, lower electricity consumption and therefore a smaller carbon footprint; secondly, increased comfort for visitors and optimum storage conditions for books thanks to better air quality; and thirdly, optimum hygiene thanks to demand-oriented air exchange,” explains Christian Oberthür. “The historic church is also a listed building, which meant we had to be particularly considerate of the building structure.” 


Significant energy savings with Kieback&Peter – “As much as necessary, as little as possible”

The result from the automation experts is a smart control system based on the en:air system from Kieback&Peter. It ensures consistently good air quality by means of precise switching operations. The modification work was able to be carried out while the library continued to operate, with the team integrating additional CO2, humidity, temperature and pressure sensors. Based on the measured values from these sensors, the digital automation system calculates the optimal volume flow rate for the supply and extract air. Since the speeds of the two ventilation fans are now variably adjustable thanks to the newly integrated frequency converters – and no longer just 2-speed – they can deliver the exact amount of air required at all times. If required, the system can be operated using the Qanteon building and energy management system from Kieback&Peter in the town’s data center – the building automation systems of other properties are also controlled centrally from here. Christian Oberthür summarizes the project by saying: “Our technology now detects automatically how much fresh air is actually needed based on the air parameters measured and controls the fans continuously. This guarantees optimum air quality at all times and significantly minimizes energy consumption – for heating by around 30 percent and electricity by around 15 percent. In keeping with the motto “as much ventilation work as necessary, as little consumption as possible.”


The smart ventilation control system, en:air from Kieback&Peter, continuously measures the air quality and regulates the supply and extract air fans as required. © Tino Sieland

Mühlhausen Municipal Library – The technology at a glance:

  • Digital networking of all building systems for ventilation and heating in a central automation solution 
  • Integration of 70 physical data points into two automation focal points (ASPs)
  • Networking of two controllers of the type DDC4000
  • Digital linking of all connected systems with the central analysis and monitoring software Qanteon in the data center for the town of Mühlhausen