Daycare in Köln-Finkenberg: Integration for children – Innovation for the climate

The Köln-Finkenberg children's day-care centre has developed a sophisticated energy system: The facility is heated and cooled by a heat pump system supplied by various heat sources. The centre obtains up to about 70 per cent of its power from an in-house photovoltaic system. This also shows in its operating costs: The Köln-Finkenberg children's day-care centre pays about 80 per cent below the average.

During the construction of the Kindertagesstätte (Kita) Köln-Finkenberg children's day-care centre, which opened in 2014, supporting organisations Haus der Offenen Tür Köln Porz e.V. (open house organisation in Porz, Cologne) and DRK Ortsverein Porz e. V. (local German Red Cross association, Porz) emphasised a sustainable energy supply. At the heart of the centre’s innovative energy concept is a heat pump system that primarily uses an ice storage unit and an underground storage unit for its air conditioning.

Engine for progress:

  • Reducing operating costs by 80 per cent
  • Reducing CO2 emissions by 27 tonnes annually
  • Innovative combination of various heat sources

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Photo: Architekturbüro Wittkowski & Partner

The completed building accommodates about 100 children.

Cooling and heating using ice

Air absorbers installed on the roof assimilate energy from direct solar irradiation and atmospheric air and feed these into an ice storage unit. A heat pump raises the temperature in order to heat the centre’s rooms in the winter. If the air absorbers do not provide enough heat during the colder months, the heat pump extracts energy from the water stored in the ice storage unit to heat the rooms.

The heat pump draws heat out of the ice storage unit during the heating period, producing cold. At the end of the heating period, this is saved in the form of ice until the following summer when it is used to cool rooms down.

Seasonal underground storage unit as heat buffer

Due to the soil quality, a lot of earth had to be moved in order to build the children's day-care centre. In this context, the people responsible came up with the idea of installing an extra seasonal underground storage unit underneath the building, where excess heat could be stored. The excess heat assimilated by the ice storage unit’s solar absorbers, together with a “power roof” that uses the waste heat generated underneath the photovoltaic (PV) modules both act as heat sources. Photovoltaic systems reach temperatures of up to 80 degrees Celsius in the summer and up to 30 degrees Celsius in the winter. This compromises their performance. In the “power roof,” air absorbers are attached underneath the PV modules, which assimilate the heat from the modules and the atmospheric air and conduct it to the underground storage unit. As a result, the performance of the PV modules benefits from a cooling effect amounting to roughly 20 per cent. Moreover, the heat stored underground can be used to heat rooms and preheat fresh air.

Self-sufficient and cost-effective

The building does not require any additional heat source. The building also supplies itself with up to 70 per cent of its power requirement from the PV system, thereby covering the water heating demand also. At 0.31 euro per square metre and month, the costs of heating, cooling and ventilation are about 80 per cent below the German average. So it is no surprise that this energy strategy is set to be transferred to a similar construction project in Cologne.

Children and young people all under one roof

The building design is also barrier-free and is thus optimally suited to an integrative children's day-care centre. The centre accommodates about 100 children between the ages of two and six. The centre also facilitates young people – in a separate area supervised by the Offene Tür Arche Nova (Arche Nova open door) youth workshop.

Photo: Wienerberger / Ralf Pieper

“For the client – Haus der Offenen Tür e. V. – this project was less about the yield and more about quality and sustainability. To us planners, both of these parameters concern not only energy-related matters, but also all materials used. After two years of monitoring, the result shows that our expectations and prognoses have even been exceeded.”

Werner Wittkowski (left), owner of architect’s office Wittkowski & Partner, with the client Walter Grau, from the Executive Board of Haus der Offenen Tür e. V.

Partners and sponsors

  • Wittkowski & Partner
  • PBS Energiesysteme GmbH
  • Stadt Köln
  • Haus der offenen Tür Köln Porz e.V.
  • DRK Ortsverein Porz e.V.
  • Ministerium für Klimaschutz, Umwelt, Landwirtschaft, Natur- und Verbraucherschutz (MKULNV)
Counselling centers:
  • EnergieAgentur.NRW