strausburgerplatz_001_edited

The stunning exterior of Alexanderplatz, designed by Christoph Ingenhoven, showcasing its integration with the natural landscape and sustainable design elements

strausburgerplatz_001_edited

The stunning exterior of Alexanderplatz, designed by Christoph Ingenhoven, showcasing its integration with the natural landscape and sustainable design elements

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PROJECTS / ALEXANDERPLATZ BERLIN

Residential Passive High-Rise

The new high-rise at Alexanderplatz is a defining element of the Berlin skyline. The unique facade design, featuring protruding and recessed balconies and loggias tailored for hotel and residential use, along with the materiality of the facade surfaces, makes the 150-meter-tall building a recognizable landmark in Berlin-Mitte.

Due to the urban placement of the building site, the orientation of the building's sides is largely predetermined. However, through the careful arrangement of transparent and opaque facade elements, as well as balconies, terraces, and loggias, it is possible to optimize the orientation, which is especially important for residential use, and to organize equally valuable apartments.

The design meets the social qualities and the desire for privacy for the owners of the high-end residential units through the arrangement of the lobby and access areas, as well as through the staggered placement of the balconies. This largely prevents direct visibility into private areas of adjacent apartments and minimizes overshadowing caused by overhangs. Architecturally, this is resolved by creating green terrace areas that act as small gardens in front of the apartments. These gardens also shape the building’s appearance from a distance, as visible balustrade elements and floor edges are replaced by greenery in these areas. For added comfort (to reduce fear of heights, provide wind protection, and enhance views), the balconies feature closed balustrade elements with a glazed top section.

The resource-efficient green building concept is developed according to the criteria of the DGNB (German Sustainable Building Council) and optimizes all material and energy flows within the building. The new development at Alexanderplatz will be the world's first residential passive high-rise – a key factor in this is the energy-optimized building envelope.
Creation of comfortable indoor temperatures and prevention of summer overheating through innovative facade and climate control concepts.
Sustainable management of energy resources. Minimization of primary energy demand for heating, cooling, ventilation, and lighting >> intelligent facade and climate control concept with environmentally friendly energy generation, reducing the EnEV 2009 standards by at least 15%.

The building envelope, cubic form, and technical equipment guarantee the highest energy efficiency while meeting the high usage demands for indoor climate and comfort. Thus, all relevant energy-saving criteria are exceeded, and the requirements for a passive house are met.

In terms of construction, the facade’s protective and supply functions are coordinated to optimize both active and passive solar gains, providing users with maximum comfort. The proportion of window area is adjusted based on the orientation, and highly insulated triple-glazed thermal windows are used. The glass portion of the facade is limited to a maximum of 60%. The air-tightness and high thermal quality of the facade minimize heat transmission losses. Operable windows also support natural night-time cooling when needed.

The apartments are equipped with controlled ventilation systems, using decentralized units with integrated heat recovery. Excess heat from exhaust air is effectively recovered and reintroduced into the rooms. The climate control concept combines energy optimization with individual user needs. Heat is provided using local resources to meet passive house standards.

Beyond conserving energy resources, water consumption is also minimized. Optional rainwater and greywater reuse systems are key components of the sustainability concept. The greywater from showers and sinks can nearly meet the non-potable water demand for toilet flushing. The necessary treatment facilities are located in the basement as modular systems, reducing distribution system lengths. Rainwater collected from rooftop surfaces may also be used for exterior irrigation.

Additionally, with the optional integration of photovoltaic (PV) elements in the vertical facade sections on the southeast and southwest (non-shaded, opaque areas), a significant portion of electricity consumption can be covered. By combining PV with a combined heat and power (CHP) system, the building can approach a net-zero energy standard, as over the course of the year, the building's energy production can nearly cover its consumption.

The orientation of window areas in the apartments optimizes natural daylight, minimizing the need for artificial lighting. Exterior sunshades efficiently prevent summer overheating and allow for the utilization of solar gains in the winter.