Schwandorf District Offices

IMI Hydronic Engineering AFC technology solves decades-long problem

The Project

The Schwandorf district offices in Germany had been having problems with the hydronic balancing of its heating system since 1990. Radiators had been fitted with manual radiator valves that could only be fully opened or fully closed resulting in extremes of temperatures. A switch to district heating and the installation of a building management system had also impacted energy efficiency. Officials made the decision to engage consulting engineers, Süss, to resolve the issues.

The Challenge

Constructed in 1977, the Schwandorf district office administration building is home to more than 300 employees and is responsible for the administration of one of the largest districts in Bavaria. Built in a cross configuration with four wings, the technical infrastructure distributes heat through separate heating circuits.

The building’s large complex pipe network was only partially documented and initial calculations showed the high differential pressures in the system meant even modern, pre-settable thermostatic valves could lead to noise. Süss approached IMI Hydronic Engineering about its range of TRVs with integrated automatic flow control (AFC) technology as a solution to their challenges.

The Solution

By installing an AFC valve on every radiator and setting the maximum flow, hydronic balancing could take place automatically throughout the heating system and the valve setting could be determined without knowing the exact system structure. Unlike pre-settable thermostatic valves, which can be noisy with a differential pressure of just 20 kPa, the innovative new valves were designed for differential pressures of up to 60 kPa, meeting the requirement for quiet operation. The installation of the AFC thermostatic valves also meant the need for differential pressure controllers was unnecessary, saving the cost and inconvenience of major drilling and welding works.

To test the solution, officials installed the AFC technology in just the eastern wing of the administration building. During the 2013/2014 heating season, the wing managed to achieve an optimum temperature differential for district heating in comparison to the other wings which showed high levels of inefficiencies – this led to the remaining heating circuits being equipped with AFC technology in 2014. Standard sizes and easier handling allowed the installation to be carried out quickly and without disruption to the office workers.

More than 650 thermostatic valves equipped with AFC technology were installed in the Schwandorf district offices in addition to IMI Hydronic Engineering lockshields and thermostatic heads: 50 tamper-proof B–heads and around 600 K-heads. Test measurements were carried out on the supply pipes, confirming that the flow was exactly as calculated.​

"It was hard for us to believe that we could solve our decades-long hydronic problems and achieve an optimum differential temperature by simply installing these new valves without the need to calculate and adjust the entire system." Joachim Ziegltrum, Schwandorf district offices​.


Office & Commercial buildings
Schwandorf District Offices

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