Forward-looking project in Moers: VIVAWEST replaces gas boilers with dwelling stations

The energy efficiency of buildings plays a key role in achieving climate targets. In Germany, buildings are responsible for around 35% of final energy consumption and cause around one third of CO₂ emissions.This is partly due to the heating technology used. Threre are still around 4 million gas boilers in use across the country. These need to be replaced by sustainable energy sources, preferably in conjunction with modern dwelling stations. The housing company VIVAWEST relies on the Oventrop Regudis W-HTE GT dwelling station for this - for example in a housing estate with six multiple dwellings in Moers.

In order to achieve the German government's ambitious climate targets, the ecological footprint of the German building stock urgently needs to be improved. One of the levers for this is the decarbonisation of heating systems in existing buildings. Carbon-based heating systems must be replaced by new, more envionmentally friendly engery sources - this is the aim of the German Building Energy Act (GEG). The housing company VIVAWEST, one of the largest portfolio holders in North-Rhine-Westphalia with 120,000 dwellings, set itself extensive sustainability targets back in 2016, which have been repeatedly adjusted over the years. "In addition to creating a climate-neutral building stock by 2045, one of these goals is to test innovative products, processes and technologies for more environmentally friendly portfolio management," says Mathias Ruß, Project Manager at VIVAWEST.

Optimally coordinated – Heat pumps and dwelling stations

The most recent example is a housing estate with 46 residential units in six multiple dwellings in Moers. While the buildings were occupied, the old gas boilers were replaced by a central heating system with heat pumps until the end of 2023. The new Oventrop Regudis W-HTE GT dwelling stations are used for decentralised dwelling-by-dwelling heat distribution for room heating and hot potable water preparation. "Everywhere in Germany, as in the housing estate in Moers, there are inefficient gas boilers that need to be replaced by climate-friendly solutions. The dwelling station was developed precisely for this application", explains Michael Ricke, Key Account Manger for the North/West region at Oventrop. The dwelling stations are an efficient solution for existing buildings to supply dwellings with heat and hot water. Compared to centralised hot water preparation, which has to be operated at high temperatures all year round in multiple dwellings, the dwelling stations can be operated at a lower temperature level thanks to decentralised hot potable water preparation. This supports the efficient operation of heat pumps. "The efficiency is fantastic. With heating water at 56 degrees, you can heat potable water up to 55 degrees", praises Ruß.

Maximum hygiene standards

In addition, dwelling stations ensure hygienically safe hot potable water preparation. They provide hot potable water in a decentralised manner via a highly efficient heat exchanger consisting of thin, finely structured stainless steel plates. Cold potable water and hot heating water are channeled past each other in the heat exchanger according to the continuous flow principle and the potable water is heated only when it is needed. This makes hygiene standards possible that cannot be achieved with a centralised solution - and they pay off: As the dwelling stations only heat the potable water when it is needed, there is no need to store hot potable water. This eliminates the cost-intensive obligation for regular legionella testing in the entire building.

Simple hydronic balancing

Hydronic balancing is also considerably simplified by the dwelling stations - for example, thanks to an integrated multi-functional valve. "Every dwelling in Moers has a differential pressure control valve, which makes it possible to carry out hydronic balancing quickly and effectively at the radiator without the need for balancing regulating and pipeline valves in the distribution system", says Ricke. A not insignificant advantage, as hydronic balancing will be a legal requirement for every newly installed heating system in Germany from 1 October 2024, regardless of the energy source, in accordance with §60c of the German Building Energy Act GEG.

Existing connections can be used

The Regudis W-HTE GT reveals its full potential in the field of modernisation not least during installation which was carried out in Moers by Gerhard Mölleken GmbH & Co. KG. As the connections of the dwelling stations are arranged in such a way that the existing connections can be reused, the experienced installers were able to carry out the installation quickly. The new supply pipes were routed through the old chimney shafts and connected to the dwelling stations from the top. The outgoing pipework for the dwelling is located at the bottom. Furthermore, with a width of 440 millimetres, the dwelling stations fit exactly in the place of the old gas boiler - and the precisely fitting surface-mounted bonnet provides optimum coverage of the dwelling stations and the pipework. "This is of course ideal for refurbishment. A super product for the housing industry", reports Gerrit Mölleken, Managing Director of Gerhard Mölleken GmbH & Co. KG.

Every gas boiler is replaceable

The project in Moers shows: Every gas boiler is replaceable - preferably with a dwelling station. In the case of the Regudis W-HTE GT, it was even possible to replace it while the building was occupied and during the heating period. It is these practicable, efficient and quickly realisable solutions that can lead the German building stock into a climate neutral future.