UNStudio has remodelled the Hanwha Headquarters in Seoul with a new, energy-generating facade featuring integrated solar panels, as well as providing an extremely flexible programme in the building. 

Named Hanwha Headquarter Office Tower, UNStudio has modernised the facade of the headquarters of the world's market leader with solar panels to meet the most up to date sustainability requirements. Based on environmental considerations, a conscious decision was made to remodel the existing building, rather than for demolition and new build.

By way of an efficient construction method, UNStudio and Hanwha were also able to ensure that the employees could continue to work in the building throughout the renovation. 

The result of this "remodelling in place" is a building with a healthy indoor climate, an extremely flexible programme and a completely new, energy-generating facade with integrated solar panels. As such, the building now also effectively expresses the identity and ambitions of the Hanwha Group.

The existing facade consisted of horizontal bands of opaque panelling and single layers of dark glass. In the remodelling, this is replaced by clear insulated glass and aluminium framing.

The retrofit of the office tower incorporates the remodelling of the facade, the interior of the common spaces, lobbies, meeting levels, auditorium and executive areas, along with the redesign of the landscaping.

Located on the Cheonggyecheon in Seoul, the 57,696-square-metre headquarter building was seen to no longer reflect Hanwha as one of the leading environmental technology providers in the world. 

For the competition to remodel the tower, UNStudio teamed with Arup as sustainability and facade consultant and landscape designer Loos van Vliet. Following the selection of the competition design, agLicht joined as lighting consultant.

The retrofit of the facade and the interiors was carried out while the building remained fully occupied and functional, thus enabling the company to remain working in the building throughout the construction period. In order to enable this, three floors were refurbished at a time, in both the interior and on the facade.

Electing to choose a construction method that would have minimal impact on both the operation of the company and on the environment, serves as a good example for all stakeholders in the construction process to consider alternative parameters and sustainable measures that can be introduced when retrofitting existing buildings.

The basis for the facade expression is to achieve an effect of variety, irregularity and intricacy throughout. This expression is informed by the sun and orientation factors, as well as the programme: by varying the placement of the facade panels a variety of programme-related openings are created.

Responsive facade concept

Addressing the request that the design be guided by the surroundings, influenced by nature and driven by the environment, UNStudio developed an integrated responsive facade concept which improves the indoor climate of the existing building and reacts to both the programme distribution and the location.

"By means of a reductive, integrated gesture, the facade design for the Hanwha HQ implements fully inclusive systems which significantly impact the interior climate of the building, improve user comfort and ensure high levels of sustainability and affordability," said Ben van Berkel, founding partner of UNStudio. 

"Through fully integrated design strategies today’s facades can provide responsive and performative envelopes that both contextually and conceptually react to their local surroundings, whilst simultaneously determining interior conditions."

In the design for the Hanwha headquarter building the north facade opens to enable day lighting within the building, but becomes more opaque on the south facade, where the sun would otherwise have too much impact on the heat load of the building. 

Openings within the facade are further related to the views: opening up where views are possible, but becoming more compact on the side adjacent to the nearby buildings.

Solar impact and PV integration

Direct solar impact on the building is reduced by shading which is provided by angling the glazing away from direct sunlight, while the upper portion of the south facade is angled to receive direct sunlight.

PV cells are placed on the opaque panels on the south / southeast facade at the open zones where there is an optimal amount of direct sunlight. Furthermore, PV panels are angled in the areas of the facade where energy from the sun can best be harvested.

Landscape design: the fluid design of the plaza landscape encourages people to enter from all sides, while the multifunctional planters not only serve as a wayfinding element, but also provide customised seating areas.

Interior concept - main lobbies, lift lobbies, office levels and meeting levels

In UNStudio’s concept for the lobby of the Hanwha headquarter building the landscape continues into the interior and acts as a guiding aid, while natural materials and planting provide a relaxing environment for visitors.

A subtle colour scheme is combined with wooden furnishing and, in both the north and the south entrance lobbies, a coffee corner creates the possibility for social interaction and exchange.

The increased floor to ceiling height of the lobbies is emphasised through the new facade design by increasing the daylight entering the lobby areas and creating visual connections between the outside plazas and both lobbies.

At the lift lobbies, intuitive guidance through interior design elements and integrated lighting seamlessly connects the common areas and hallways at all office levels.

This linkage between lift lobbies and the common reception areas and hallways creates a common identity at the different levels, yet enables flexibility in the workspaces and the allocation of different type/sizes of offices, both now and for the future.

Image courtesy of UNStudio

The wayfinding strategy continues through to the meeting rooms, creating spaces enclosed by glass, with different degrees of transparency to create enough privacy but also create enough translucency to guarantee well-lit meeting spaces.

Among the different types of meeting spaces is the multi-purpose auditorium, which can be set up in different arrangements in accordance to the event type or meeting.

The wall cladding in the auditorium is designed to ensure good acoustics, while animated lighting and different settings enable the atmosphere to be adjusted as required for different events.

Interior concept - restaurant and executive levels

The collective spaces serve all the employees of Hanwha, bringing together the different departments and providing informal spaces for social gathering with high spatial and material qualities.

The 28th floor restaurant is a space of rest, relaxation and nourishment. Warm wood tones, natural materials and green planting create spaces where the employees of the headquarter building can come to recharge and rejuvenate. The restaurant is divided into multiple zones each catering to different types of cuisines and dining.

Image courtesy of UNStudio

Colour accents found in the textiles and furniture differentiate the multiple zones and give it an individual character. The private dining has a more intimate feel with a darker wood colour palate and intricate lighting details.

The different boardrooms at the executive level (level 27) have also undergone a full renovation. The interior design mixes zones for meeting activities that are more formal, with more social and informal meeting areas.

Image courtesy of UNStudio

On the executive level, the interior concept combines the guiding principles of wayfinding through lighting and creates within a large corporate office floor, several private and custom designed zones that offer various possibilities for working and meeting in different constellations, from small meetings to focused work, to large boardroom gatherings.

Image courtesy of UNStudio

Project facts

Architects: UNStudio

Client: Hanwha Group
Location: Seoul, Korea

Building surface: 57,696 m2 above ground
Building volume: 250,174 m3

Building site: 15,333 m2 Shared Plot

Program: Renovation of facade, interior of common spaces and lobbies, meeting levels including auditorium and executive areas, redesigning of the landscape.

Status: Completed December 2019

Team: Ben van Berkel, Astrid Piber with Ger Gijzen, Marc Salemink, Sontaya Bluangtook and Martin Zangerl, Hyoseon Park, Gabriele Decandia, Andrea Wong, Daniele de Benedictis, Luke Tan, Jooyoun Yoon, Nina Soltani, Albert Gnodde, Shuang Zhang, Yi-Ju Tseng, Alberto Martinez, Philip Knauf

Local consultant and executive architect: Gansam Partners

Consultants

Landscape consultant and designer: Loos van Vliet, Haarlem
Facade and sustainability consultant: ARUP Hong Kong

Lighting consultant interior and facade: AG Licht, Cologne 

All images © Rohspace unless otherwise stated.

All drawings © UNStudio 

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