All things environmental

Musings about the environment and all it touches, from education to city planning

The Doppel X building

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WEB JH656-134-1

Doppel X at night, a photo from the rental agency

Architecture geek that I am, I went to take a look at the Doppel X building, a twelve-story office tower completed in 2000. Designed by Hamburg starchitect Hadi Teherani, the building won several prizes and incorporates low-cost construction material with energy saving features, as well as indoor gardens. It owes its name (double x) to its floor plan, which looks from the air like a double cross.

When I went to visit the building was eerily empty. I later found out that its tenant, a large insurance company, pulled out in 1999 as the economic crisis worsened. One of the design flaws of the building, all 17,000 m2 of its floor space, may be that it is meant for occupancy by a single tenant.

The empty building when I visited

The empty building when I visited

But it won’t remain empty much longer. Faced with a critical shortage of of housing, the city has decided to rent the building and convert it into housing for 1100 refugees. In Hamburg, there is a vacancy of nearly one million square meters of office space, and half of this will be conscripted for temporary housing, the city paying market rates for renting the space. How the refugees will adapt to these unusual living quarters remains to be seen, but it has to be better than tents.

I knew none of that when I went to see the building, which intrigued me for several reasons. One is the envelope: this tower looks from a distance as if covered in cling-wrap. This is an external, transparent wall that serves to further insulate the building and act as a sound barrier, while allowing natural light to shine in as well as allowing for natural ventilation. Double X has taken this approach to an extreme, where the outside cladding encloses a rectangular space that includes much of what would normally be considered “outdoors”. Several other buildings also use this approach, notably the nearby Berliner Tor Centre and the Unilever Tower in Hafen City.

Another thing that I noticed is the fact that the energy performance – how much heat and electricity is needed to run the building – is clearly advertised on real estate sites that advertise office space for sale or lease. I later found out that this is a legal requirement.

Indoor gardens are an integral part of the design

Indoor gardens are an integral part of the design

According to its Energieausweis für Nichtwohngebaüde (energy certificate – for non-residential buildings, ironically), heat comes from district energy at a rate of 209.7 kwh/m².a, while the electricity needed is 58.6 kwh/m².a. The audit certificate, valid until 2020 (all buildings must have one), states that the building is operating better than the average building of this type (320 kwh/m².a, if you must know). The certificate looks like the “Enersave” designation we use in Canada for appliances, but with many more details. For instance, specific amounts of energy for ventilation, heating, lighting, and air-conditioning, are all listed. It also states that the CO2 emissions are 83 kg/m².a.

And of course, the degree to which the indoor plants are an integral component of the building is pretty cool. There used to be a indoor pond, as well, but this water feature has been replaced by a glass shard sculpture. The water was causing some humidity issues for the tenant. A design flaw, to be sure, but I love the fact that here, builders are willing to try new approaches.

The other two buildings I mentioned that use this double envelope approach, the Berliner Tor Centre and the Unilever Tower, are both highly performing buildings themselves. But this double envelope is not a must for energy savings; while looking up the Unilever Tower, I stumbled upon an article about the old Unilever Tower, a bland 23 story tower built in the 60s, now known as the Emporio building.

The facade of the Berliner Tor Centre, showing the envelope element

The facade of the Berliner Tor Centre, showing the envelope element

This building was completely renovated –rejuvenated, really – in 2012. The original glass of the transparent façade was removed and replaced by modern, high-efficiency glazing. The building is now as performant as a new design; its CO2 emissions and energy requirements per square meter of floor area are actually better than that of the Doppel X. The Emporio is now rated silver for the German Sustainable Building Council and LEED platinum.

Hmm…LEED platinum, German silver, something tells me that the German criteria are somewhat more demanding. But the key lesson is this: the energy hogs built in the sixties can and should be upgraded to high energy efficiency. But we can also build new, spectacular architecture, and make them supermely efficient. The technology is there to do it all.

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Written by enviropaul

November 2, 2015 at 12:43 am

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