Hotel-Restaurant Lange in Leer, Germany opened in 1972 with just 20 rooms, but as it gained popularity several extensions and structural changes were made to accommodate increased demand. Between 1972 and 2014 the hotel had grown from 20 rooms to 56, the kitchen had been extended, a swimming pool and spa facilities installed, and a new lobby area constructed. However, the years of developments paid little attention to the efficiency of the heating system, affecting the hydronic balancing of the system and resulting in poor supply to some of the radiators.
During the last renovations in 2014, hotel proprietor, Elke Frerichs, tasked HVAC specialists, Bahlmann GmbH, with designing a heating system that could fix those issues and guarantee energy efficiency, comfortable heat distribution, and be cost effective.
The Hydronic Challenge
Following hydronic balancing analysis, it was discovered that the required flows caused significant pressure losses in the radiator valves, which could normally be solved by installing standard pre-settable radiator valves combined with balancing valves. However, this involves noisy drilling and as the hotel wished to remain open to guests during the renovation, the contractor would not be able to locate some of the pipes, so it was decided to retain the existing radiators and look for a different solution.
To meet the design requirements, Bahlmann needed the support of an expert partner skilled in HVAC solutions, so they approached IMI Hydronic Engineering to discuss its latest technological innovation – Automatic Flow Control (AFC) technology.
IMI Hydronic Engineering’s new AFC technology comes packaged in a valve body which, when used together with the highly popular thermostatic K-heads, can control the maximum flow automatically and independently of the differential pressure at the valve. In addition, having been designed for differential pressures of up to 60 kPa, it also meant there would be no disturbing noise from the new radiator valves.
It was an easy decision for Bahlmann who, impressed with this new technology, engaged the technical support from IMI Hydronic Engineering to install and configure the valve bodies for a total of 148 radiators.
An additional benefit of the AFC technology is that it is easy to install, which meant the full installation was done in just 3 days. The valve setting can be determined without needing to know the precise locations of the pipework or to perform complex calculations. The contractor simply needs to install the K-head and valve body combo to the existing radiators and by adjusting the settings directly on them, it will determine the heating requirements and calculate the maximum flows automatically and independently.
As an added measure, the contractor installed IMI Hydronic Engineering’s “Dynacon Eclipse” underfloor heating manifolds, which also use AFC technology. These components now ensure that the excess differential pressure is automatically restricted at every radiator and heating circuit, so the amount of hot water flowing never exceeds the maximum setting.
Through the use of IMI Hydronic Engineering’s AFC technology, the heat distribution problems were successfully resolved and the old pumps could be replaced with smaller, more efficient models as they now have lower capacity requirements. The AFC components created a heating infrastructure that will support the hotel during future extensions without creating further hydronic problems, and the hydronic balancing alone is expected to account for energy savings of around 8%.
“It provided exactly what we needed for our particular situation – fast and reliable hydronic balancing without using manual balancing valves.”