Erfurter Ring Ludwigshafen – Energy-saving model with geothermal energy

Erfurter Ring – focus on geothermal energy

The residential units on Erfurter Ring are 2-5 room rental apartments ranging in size from 61 to 106 square metres. Spacious green areas and playgrounds create a pleasant environment for families with children, while the proximity to public transport and shopping facilities offers residents convenient access to the city’s infrastructure. The houses are designed in three types of different sizes and were built using solid construction in accordance with the KfW 55 EE standard. What makes the entire complex special is that it completely dispenses with fossil fuels for heating and instead relies on geothermal energy in combination with brine-water heat pumps. Hot water is supplied by apartment stations that heat cold drinking water only when needed, saving energy. The pent roofs are already pre-equipped for photovoltaic systems and will be extensively greened.

All residential units also have terraces or balconies and are connected to the living rooms on the common side. A geothermal heat pump is an efficient energy source that is particularly suitable where groundwater is not available or not available in sufficient quantities. A geothermal heat pump makes sense, especially if you are considering a silent heat pump.

A total of around 80 boreholes for geothermal energy were drilled on the site, seven metres away from the neighbouring probes and two and a half metres away from the buildings. This created a comprehensive network that ultimately buffers the entire heating energy for all residential units. The eight boiler rooms within the complex were equipped with products from ratiotherm that support the overall concept. For example, Oskar° stratified storage tanks in sizes ranging from 2,000 to 3,500 litres are installed as the centrepiece of each boiler room. A major advantage is that stratified storage tanks of this size can be assembled and welded directly on site in the boiler room, with delivery taking place in individual parts. These storage tanks are in turn loaded by cascaded heat pumps, which draw their energy from the probe field at temperatures of 12–8 °C. For buildings with a higher heating load, a cascade heat pump was used, which was brought into the basement in individual parts and reassembled there. This is usually very interesting in renovation projects with limited access, but can also be very helpful in new buildings, as in this case.

PV Max-Heater devices are installed in the boiler rooms as an emergency backup system to compensate for peak loads and technical malfunctions. The PV Max-Heaters were specially developed for the use of surplus electricity from natural power plants. The associated measuring device records surplus electricity and determines the available energy in real time. This is forwarded to the continuously adjustable device (up to 12 kW), which heats the hydraulically integrated heat storage tank for later use for heating and domestic hot water. The Max-Heater varies the speed of the integrated pump depending on the amount of electricity available in order to always produce water at the flow temperature set by the user – comparable to a conventional heating system. This is also the biggest advantage over conventional heating elements, as only heat at the required temperature level is produced. In this way, the surplus power from the PV system is converted into heat energy and stored as renewable energy.

The connected systems are controlled centrally using specially programmed control technology and are easy to operate. ratiotherm installed a so-called EWS apartment station in each of the 146 flats. This ensures, for example, that drinking water is heated on site when it is needed and thus helps to determine the correct demand calculation for each residential unit. In addition, the EWS has a leakage function and sounds an alarm in an emergency before it is too late and water damage spreads unnoticed.