Ice storage cools and heats Hamburg office complex

14.05.2025

Source: E & M powernews

MVV Energie is developing an energy and cooling concept for the "Borx" office building in Hamburg for Strabag Real Estate - including ice storage, heat pumps and a photovoltaic system.

The "Borx" office building is currently under construction in the Borgfelde district in the east of Hamburg. This is a new construction project by Strabag Real Estate, a subsidiary of the Strabag construction group, which is active in project development.

Once completed, the office building will have a rental area of around 24,000 square meters. At its heart is a holistic energy concept developed by MVV Energie. MVV Energie subsidiary MVV Enamic has been commissioned to implement the concept.

According to MVV Energie, it is investing a mid seven-figure sum in the construction of the planned heating and cooling center, the photovoltaic system and the district heating connection. In addition, it will take over the operational management and maintenance of the entire energy infrastructure of the office building over a period of 16 years.

The building complex is to meet the KfW 40 standard, which means that it will only consume 40 percent of the maximum energy required by a comparable new building. The building is also to receive the Gold Certificate from the German Sustainable Building Council. According to MVV Energie, the certificate is a benchmark for low life cycle costs, resource conservation, user comfort and ease of dismantling.

Completion is scheduled for spring 2026

The planned ice storage facility is a water tank that stores heating and cooling energy. During heat generation, energy is extracted from the water until it freezes - the so-called crystallization energy released in the process can be used particularly efficiently. In summer, the ice is thawed again using heat from the building and is used for cooling. This significantly reduces energy consumption, as heat pumps work more efficiently in combination with the ice storage unit.

The storage unit is manufactured by the energy technology company Caldoa from Friedrichshafen (Baden-Württemberg). It will have a volume of 672 cubic meters and a storage capacity of 51,670 kWh. In combination with two heat pumps and concrete core activation, this will enable climate-friendly temperature control of the rooms all year round.

According to the partners, the ice storage facility is currently being completed. In addition, a six-metre-long, five-tonne refrigeration system with a thermal output of 450 kW has already been installed on the roof of the building. The building complex is scheduled for completion in spring 2026. Strabag intends to use the majority of the office space itself in future.

Johannes Werhahn, Managing Director of MVV Enamic, explains the Hamburg project: "We are seeing growing demand for holistic energy service models - not only in the real estate sector, but also in industry". Such models enable an efficient supply at predictable costs. What's more, the building owner does not have to tie up their own resources for planning, investment or operation.

Author: Davina Spohn