UNStudio finishes retrofitting Hanwha Headquarters tower in Seoul, South Korea

Dutch architectural firm UNStudio has completed the remodelling of the Hanwha headquarters building located in Cheonggyecheon, Seoul, South Korea. Heeding to environmental considerations, the building was decided to be remodelled, instead of being demolished and built anew. The façade of the headquarters for the world’s market leader in solar panels has rightfully, and literally been fitted with a myriad of shiny solar panels, which hold countless photovoltaic cells. UNStudio won the competition to retrofit the headquarters for the Hanwha Group in 2014, teaming up with Arup (sustainability and facade consultant) and Loos van Vliet (landscape designer), along with agLicht as lighting consultants. The Hanwha Group was founded in 1952, and is the world's third largest photovoltaic producer presently.

The renovation of their 57,696 sqm HQ tower is directed by its surroundings, influenced by nature and driven by the environment. The design programme includes the remodelling of the façade, its interiors, lobbies, meeting and common spaces, executive areas, auditorium, and redesigning of the landscape. The original façade of opaque and dark glass has now paved way for aluminium frames that hold transparent, insulated glass.

More importantly, UNStudio and the Hanwha group carried out the retrofit of the building, both inside and out, while the building remained fully functional and occupied – employees continued to work inside as the construction took place around them - by refurbishing three floors at a time. “As such, the building now also effectively expresses the identity and ambitions of the Hanwha Group,” states an official statement.

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. – UNStudio

Façade Factors

UNStudio developed an integrated ‘responsive façade concept’, which improves the climate inside the existing tower and aptly responds to the design programme and the building’s location. Ben van Berkel, founder and principal architect of UNStudio, shares, “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. 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.”

It is rightfully observed that a building’s façade sets the tone for the rest of the structure. The HQ’s façade expression seeks to achieve variety, irregularity and an intricate character throughout. This is informed by varying the façade panels and openings that are directed by the design programme of the building and the sun’s orientation. Openings on the façade are influenced by the views they provide – they open up where handsome views are possible, and become compact on the sides that face nearby buildings. The north façade opens up to allow natural light to penetrate the buildings’ insides, and becomes reserved and opaque on its south frontage, to block the intensity of the sun’s heat.

The design of the façade moderates direct and indirect solar impact by selective shading – photovoltaic cells are angled in some areas to reflect off direct sunlight where it is too intense, while in some portions to receive and harvest it.

Inside the Hanwha Headquarters Tower

The landscaping around the tower’s plaza has been done such that it creates various fluid pathways that reach the entrance. It is further enriched by multifunctional planters that guide people (‘wayfinding’) and also act as customised outdoor seating. The landscaping also hosts spaces for large gatherings and relaxation.

The landscape continues inside the interiors, greeting visitors with a relaxed ambience through natural materials and plantings. A calming colour scheme along with subtle wood furnishing with rounded, soft edges, is employed in the north and south entrance lobbies, and can be seen throughout the interiors of the tower. Higher ceilings enhance the visual connection between the two lobbies and the plaza outside, by increasing the amount of daylight entering the spaces.

Lift lobbies host interior design elements and integrated lighting that guides a visitor further, while connecting the common areas and hallways at all office levels. The wayfinding continues well through to the meeting rooms and other interior spaces as well. Here, UNStudio uses glass of varying transparencies that enclose spaces to guide people, while balancing translucency with privacy in these well-lit areas. The multipurpose auditorium can be configured in various ways, according to the type of meeting and event. The wall cladding here is designed for good acoustics, while the atmosphere is attuned through adjustable animated lighting.

All employees of Hanwha are brought together in collective spaces designed within the tower, especially the 28th floor, which hosts spaces for nourishment and relaxation. It houses a restaurant that has multiple zones for different types of dining and cuisines. The floor is clad in warm wood tones, natural materials and lush plantings, augmenting it as a space for rejuvenation. The accents of colour in the furniture and fabric also differentiate the areas. A darker wood colour palette with intricate lighting separates the private dining from the rest. Level 27 hosts various boardrooms that have also been fully renovated, with a subtle mix of formal and informal meeting areas that are informed by the interior design.

UNStudio is known to design projects with great emphasis on sustainability roped in by technological prowess. Read here to explore more works and concepts by the international firm.

Project Details

Name: Hanwha Headquarters Remodelling
Location: Seoul, South Korea
Building surface: 57,696 sqm (above ground)
Building volume: 250,174 m³
Building site: 15,333 sqm shared plot
Year of completion: 2020
Architect: UNStudio
UNStudio 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
Landscape consultant and designer: Loos van Vliet, Haarlem
Facade and sustainability consultant: ARUP Hong Kong
Lighting consultant interior and facade: AG Licht, Cologne