The Breuskesbach housing estate in Recklinghausen was built in the late 1970s to provide housing for the employees of the Zeche General Blumenthal coalmine and their families. However, over time and with the decline in mining, the four-to eight-storey block complex began to look dated.
Landowner, Gelsenkirchener VIVAWEST Wohnen GmbH, the biggest housing association in Germany, decided to undertake the renovation of the buildings’ façades and with building technology consultants, Wasser + Licht GmbH, an upgrade of the energy infrastructure. To mark the start of a new era the project was renamed the New Recklinghausen City Gardens.
The Hydronic Challenge
The €22 million renovation project of 369 flats across ten building blocks, required a full upgrade of all heating pumps to deliver a high-efficiency heating system. Building managers also decided that to safeguard the pumps from debris in the hot water circuit and to help prolong the lifespan of the system, an automatic dirt separator should be installed in each building.
Hydronic balancing was paramount to ensure the system was adapted to meet the strict efficiency specifications. Traditionally, this is performed by equipping radiators with modern, pre-settable thermostatic valves and fitting differential pressure controllers on the risers. However, the problem with large pipe networks is there is a risk of the network not being fully documented and therefore design parameters are based on assumptions. Wasser + Licht went to IMI Hydronic Engineering to discuss the thermostatic valve body with automatic flow control (AFC) technology as a way of overcoming this challenge.
The new AFC technology automatically controls the maximum flow directly at the radiator, completely independently of the differential pressure at the valve. This means there was no need for the consultant to install differential pressure controllers.
In addition, this innovative technology meant the detailed knowledge of the pipework was unnecessary as the water needed for the radiators was determined by the heat load; overcoming one of the building’s key challenges. The only constraint was that the pump head could not exceed 60 kPa and the New Recklinghausen City Gardens met this requirement.
The new valve bodies automatically balanced the entire system, even with partial load, a common occurrence at the complex. All radiators were supplied with the right amount of hot water depending on the room temperature, even during morning start-up or if the valves nearby were closed. Lastly, thanks to the fact the products are designed for differential pressures of up to 60 kPa, the valves were quiet in function.
Integrating AFC technology in a standard valve body means that valve inserts can be replaced quickly, if necessary, without the need to remove the entire valve and drain the system – the perfect solution that also reduces any future inconvenience for tenants.
To protect the new system from dirt, and to ensure the high performance of the valve bodies, IMI Hydronic Engineering installed its highly-efficient Zeparo Cyclone dirt separators. The new cyclonic technology removes dirt up to 9 times more efficiently than similar products in the market, extending the lifespan of the system and lowering maintenance costs.
in material costs was saved per supply pipe compared to the conventional solution using standard pre-settable automatic thermostatic valves and differential pressure controllers. Hydronic balancing meant that the entire system worked much more efficiently in terms of energy usage, resulting in a noticeable reduction in the total energy consumption of the estate and lower energy bills for individual households.
The replacement of the thermostatic valve bodies was mostly carried out in strands, so that only certain apartments were affected by the measure for a maximum of one day.
Since the installation of the AFC technology does not differ from the installation of conventional thermostatic valves, the replacement measure could be carried out in the entire settlement within only around three months with minimal disruption for the tenants.
Those involved in the project agree that the use of AFC technology will make the planning and implementation of hydraulic balancing in the “New Recklinghausen City Gardens” much easier.