Climate protection housing development in Cologne-Porz: VIVAWEST builds Europe's largest ice storage tank

Since 1990, the housing provider VIVAWEST has almost halved the CO2 emissions of its residential properties per square metre of living space. With the construction of a multi-generation climate protection housing development in Cologne-Porz, the company is saving a further 146 tonnes of CO2 per year – and is pursuing new technological routes: with the hitherto largest ice storage tank in Europe.

VIVAWEST not only pursued environmental objectives with the construction of the multi-generation climate protection housing development in Cologne-Porz: The residential properties were to be almost barrier free and to provide attractive features for all generations. Proximity to the hospital also provides access to supplementary emergency facilities and services, if so required.

Engine for progress:

  • climate protection housing development for all generations
  • ice storage tank makes the use of the solar energy more flexible
  • the residents enjoy a high quality of living
  • 146-tonne reduction in CO2 emissions

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Photo: Dirk Bannert

The water in the 1,200 cubic metre storage tank usually has a temperature in the region of the ground temperature. The heat pump increases the temperature to the required level of 32 °C. In particular, the solar absorbers help to replace the heat taken from the storage tank. In spring, the storage tank freezes when no heat is applied. The cold can then be released directly to the underfloor heating via the heat exchangers and used to cool the living areas.

Heating in winter and cooling in summer – with one of the largest ice storage tanks in residential building

The result was a climate protection housing development in the superlative: The multi-generation housing development gets its energy from light and heat, which is then stored in one of the largest ice storage tanks in Europe. The 1,200 cubic metre storage tank is installed in the ground without insulation, thus also using the existing geothermal heat from its surroundings, because, as a rule, the water in the ice storage tank is colder than the ambient temperature of the ground. In the winter, a heat pump increases the temperature to the level required to provide heat and hot water for the homes in the development.

The solar absorbers installed on the roof surfaces replenish the heat extracted from the tank. They absorb heat from sunlight and from the atmosphere and send it to the storage tank. In addition to this, heat from the waste air from the apartments is released to the energy storage tank.

The ice storage tank lives up to its name only in spring, at the end of the heating season. When the feeding-in of solar energy is low because of the season, it uses the latent heat that is additionally released through the controlled freezing of water.

As a result of the low water temperatures, in summer, the storage tank can also cool the underfloor heating system via the heat exchangers, which can alternatively be used to cool the living area if so required.

One of "100 Climate Protection Housing Developments" by EnergieAgentur.NRW

The climate protection housing development in Cologne-Porz is part of the "100 Climate Protection Housing Developments" project by EnergieAgentur.NRW. Its innovative method of supplying energy not only benefits the climate, but also the inhabitants: Roswita Pütz from House No. 7 praises it by saying: "The latest heating technology is installed here and the utilities costs are very low. Here one has a real quality of living."

Photo: Michael Wolff Fotografie/Junkers

"Thanks to the renewable energy collected during the warm period of the year, during the winter that follows the seasonal energy storage tank is the central source of energy for heating the buildings and providing hot water. Through this combination of storage technology and the use of ambient heat, the costs for the users can be kept at a favourable level in the long term."

Dipl.-Ing. Ulrich Farwick, Portfolio Management / Site Development, VIVAWEST

Partners and sponsors

  • Ministerium für Klimaschutz, Umwelt, Landwirtschaft, Natur- und Verbraucherschutz (MKULNV)
  • KfW-Bank
Counselling centers:
  • EnergieAgentur.NRW