Sustainability Report

Embodied carbon overview

• The respectful treatment of the existing structure formed part of a comprehensive sustainability approach, with the aim of renovating the building using as little grey energy as possible. As a result, very little new building fabric was added, apart from the extension of the large aquarium, which was required for routing. All new building envelopes not connected to water or soil were constructed from wood.
• Dismantled materials were reused wherever possible. The flooring in Westhof consists of historic granite stones that had been stored by the museum for many years. Masonry work was carried out using existing bricks and fire protection glazing was removed, secured, and reused elsewhere.
• Existing elements were retained and adapted where possible. Cloakroom lockers were refurbished and reused and all existing windows were preserved. Railings were only replaced where required to meet building regulations. Removed timber was refurbished and reused, for example as stair treads or benches.
• The paving in Katharinenhalle was retained in full. The north courtyard, including its paving, trees, and museum ship, remained largely unchanged. The existing steps in front of the forum were widened to provide barrier-free access to the new main entrance. By retaining the existing ground levels, the former entrance to Katharinenhalle with its archway remains visible.
• The approach to the technical equipment followed the same principle of reusing existing materials. Functioning components from the existing building were retained, including reservoirs, skimmers, and pipework associated with the aquarium systems.
• More broadly, sustainability considerations were closely tied to the continued use and adaptation of the existing historic structure. The retention and reuse of significant parts of the building fabric formed part of the overall approach.
• No formal sustainability certification, such as DGNB or comparable frameworks, was pursued for the project.

Operational emissions overview

• The technical systems were reduced to essential elements, with active ventilation largely avoided. Existing radiators and pipework were retained where possible. At the same time, the heating systems were replaced. Air-to-water heat pumps with heat recovery and rotary heat exchangers were introduced, enabling up to 80 percent energy recovery. New building elements were equipped with underfloor heating and ventilation systems.
• The operation of the aquarium required particular attention due to its high energy demand. Direct current and three-phase pumps were introduced, reducing energy use compared to previous systems. Existing reservoirs, skimmers, and pipework were retained.
• Lighting across the building, including exhibition and aquarium lighting, was converted to LED technology to reduce overall energy demand.