The Green Wave of the Future is on Top

Greg Callaghan is as enthusiastic as all-get-out about green skins, and it’s easy to see why. “Living” buildings accomplish the feat of being greener than green. The many benefits include better air in the immediate area, plus an overall reduction of harmful gases released into the atmosphere in general; insulation against cold, heat and noise; and a way to utilize water which would otherwise pour down the drain or possibly even cause flooding. Callaghan says,

Green is the right word to describe the flora-embracing features now being incorporated into new and old buildings across the US, Europe and parts of Asia. We’re talking garden rooftops, multi-levelled terraced gardens, lush foliage draping exterior walls and vast, internal, Babylonian hanging gardens.

Of course every instance is different, depending on location, budget, whether the building is new or already existing, whether the installation is hydroponics-based or soil-based, and many other factors. But in general, the green roof consists of a multi-level sandwich, starting with the structural support. Then come the vapor control layer, thermal insulation layer, support panel, waterproof layer, drainage layer, filter membrane growing medium, and the glorious crown of vegetation. And that’s not even getting into the subject of green walls. When the surface treatment is right, masonry is provided extra protection by the plants it hosts.

The green roof concept started out cautiously, with small, short-rooted plants and grasses. Currently, over a hundred species of plants have been found viable for the purpose, and improvements in filtering, coating and barrier technology have made possible the use of shrubs and even trees. When dirt is the growing medium, many favor deciduous plants, because the yearly shedding of their leaves exposes the dark soil which can then absorb the sun’s heat for the building’s use. A properly designed green roof, garnished with some solar cells, can take care of itself by collecting and pumping its own water supply.

In the average city, at least forty percent of the energy consumed goes into the maintenance of its buildings — and a lot of that is spent either heating or cooling the interior so human habitation is possible. Green skins save energy for both those purposes — one report says air conditioning costs can drop 25% and overall electricity demand by 50%, and that’s just considering the inside. Outside, studies indicate that a sufficient number of green roofs can cool down the whole urban area by two or three degrees. When there’s a sweltering heat wave, even a seemingly small increment counts, and it’s been estimated that in Manhattan, for instance, greening just one-fifth of the roofs could accomplish that difference. In fact, if we slide on over to GreenRoofs.org, there’s a page of potential benefits that might astonish even the most ardent environmentalist.

The hard-headed, no-nonsense city of Chicago, which used to be known chiefly as the hog butchery capital, now wears the uncontested laurel wreath for its amazing number of buildings with vegetated roofs. In the last year alone, Chicago planted over 500,000 square feet of greenery over its residents’ heads. The City Hall set the pace, and there’s a lovely page about it here.

Australia was leery of innovation, but in the five years since Michael and Robyn Thomas produced their comprehensive and still very relevant paper for the government’s Standing Committee on Environment and Heritage, an ongoing drought has made believers out of quite a few skeptics. One of the showpieces planned for the green-skin revolution in Oz is the two billion dollar renewal of an entire precinct of Sydney, including two towers designed by Jean Nouvel and Norman Foster.

Callaghan’s article emphazises the ARCOS building in Japan’s Fukuoka City (pictured) which takes the green roof idea a step forward with not one many green roofs, 15 stories of them, like the icing on a tiered wedding cake. More great photos of this startlingly radical office building are here.

The only thing better than a green roof is an accessible green roof. When it’s created not just for energy-efficiency, but for people, it can provide the desired refreshment and even the company of birds and little animals. Sometimes you don’t need to consume the fuel and the time for a day-trip to the country. Half an hour under a tree can renew the spirit wonderfully. Remember the old Carole King/Gerry Goffin song, “Up on the Roof”?

On the roof, it’s peaceful as can be
And there the world below can’t bother me.

SOURCE: “Green skins ” 06/21/08
photo courtesy of tanaka_juuyoh, used under this Creative Commons license

A High-Performance Building in Texas

The School of Nursing and Student Community Center at the University of Texas in Houston (pictured) was chosen as an AGS case study for several reasons, according to a very explicit piece by Rives Taylor in Architectural Graphic Standards, 11th Edition. Ambitious high-performance goals were set and met. It began with a holistic approach to design and planning:

These building strategies were developed through a highly defined and premeditated process in a one-year period before design started. A collective team of experts undertook this year of intensive research, seeking the best existing research methods, design, and operational practices to direct the realization of this facility.

One of the greenest things about the School of Nursing is what happened even before the first step toward its creation. The site had previously been occupied by a research building, which was deconstructed so conscientiously that 80% of its materials were reclaimed for recycling and eventual further use.

Building Information Modeling techniques were used to formulate an initial plan, which was then, with the aid of the software, changed and adjusted along the way. BIM helped with the validation of recycled content, the balancing of CO2, and assessment of the buildings life cycle, and in other areas as well. For instance, in the matter of lighting:

The team refined their intuitive ideas using energy and daylight modeling tools with the Lawrence Berkeley National Labs… Actual lighting levels for the alternative design schemes were simulated through a yearly cycle. The measurements were then compared and decisions were made to follow specific strategies based on light quality, quantity, energy performance, costs, and other criteria.

Maximum lighting effectiveness was achieved through a combination of several different solutions including windows, four skylighted atria, sun shading devices, and artificial lighting. Daylighting is characterized here as one of the most simple and powerful strategies, because it doesn’t require a trained operations staff in order to work effectively.

Some recycled materials were used, for instance the multi-layered insulation. All materials were closely scrutinized with an eye to their low volatile organic compound (VOC) content. Once set in place, these of course also continue to perform without further human intervention. For greater energy efficiency, HVAC (heating, ventilation and air conditioning) equipment was installed with a combination of some undersized elements (pumps and fans) and some over-sized ones (ducts and pipes). Ventilation is treated separately from cooling, and a localized instantaneous hot water delivery system is the solution preferred over the traditional central hot water source. The double-paned window glass is spectrally selective.

Five tanks collect rainwater which, combined with condensation from the cooling system, provide greywater for the low-flow toilets and other uses, while potable water is to be found only in drinking fountains, sinks and showers.

The first two floors contain facilities used by the whole student body: bookstore, auditorium, café, and student services offices. The third and fourth floors are dedicated to the academic needs of the nursing school: classrooms and other learning environments. Then there is a research lab floor, topped by three stories containing offices for faculty and administration, and conference rooms. The service building is a separate structure.

The School of Nursing’s four elevations and its roof were conceived as five unique facades, each a distinct entity, and the detail with which Taylor describes the individual design approaches to the conditions and requirements on the various sides, is the highlight of this chapter.

SOURCE: “University of Texas School of Nursing and Student Community Center” AGS page 495 2007
photo courtesy of JoeBehrPalmSprings , used under this Creative Commons license

Termite Tower Ultimately Sustainable

What’s two miles high, a mile wide, and holds a million inhabitants? A termite tower reconceptualized for people. In gizmag, Loz Blain explores the implications of Eugene Tsui’s visionary approach to life on earth as it would be lived by upright bipeds in a group home designed by insects. Of course, termites don’t pay 150 billion dollars for their towers. Or maybe, in termite terms, they do? But here’s Blain, on why it’s so exciting anyway:

Designed to be virtually impervious to wind, water and earthquakes, the massive tower is conceived less as an architecture project but as a series of mini-ecosystems within which other architectural projects can be developed. And it offers some ingenious ideas on energy production, water use and intra-colony transport.

Of course, for now, the Ultima Tower remains in the realm of imagination. Lately, it no longer means anything to say a building looks science-fictional, because many now do. But this one really does. It belongs to a class of phenomena known as massive vertical solutions: huge megabuildings that actually contain whole towns, cities, or even countries. Eugene Tsui presents the tower as a framework in which many other smaller architectures can exist – including twelve large bodies of water. Plus, it sits in a lake, and the pedestrian bridges across the lake are curved, not straight. 120 levels are called for, each one of them as much as 50 meters high.

Tsui is famous for drawing inspiration from nature, though in a big-picture kind of way, it’s astonishing that looking to nature for workable, proven solutions should be considered unusual in any way. The idea for the tower came to him when engaged in a study of San Francisco, which clearly is in need of help if it is to remain livable. The architect says the whole area now has an “offensive countenance” – the best description of urban sprawl that’s been heard in a while.

The tower’s structural, water, energy, transport and safety issues are seen by the architect as the main challenges. That’s putting it mildly! Those categories cover just about everything.

So… how about those structural challenges? To distribute stress, you’ve got your double-helix cable network all around. Elsewhere, the tower described as a suspension cable bridge, only vertical. The aerodynamically valid shape resists earthquakes, and the whole thing is made from steel, concrete, stainless steel cable, anodized aluminum, ceramic, and glass.

Water? Tsui took a clue from how trees manage their hydraulics, and envisions a system of capillary action based on transpiration and cohesion to move water up. The cooling system imitates that of a termite mound, depending on water, though vegetation and windows also come into play. Also in the plans are natural water-cleansing systems and composting toilets.

Energy? The whole structure is covered with wind turbines and photovoltaic cells on walls of structural glass, and there will be a process called Atmospheric Energy Conversion. Energy comes from electricity, water or hydrogen gas, with nary a combustion engine to be found anywhere in the tower. One light source is the hollow, mirrored core and allowance is made for the need of plants to maintain tropism.

On the Ultima’s own site, we learn such interesting statistics as the amount of time an elevator takes to get to the top: about ten minutes. Of course, termites don’t have elevators. But, leaving that aside, should humanity emulate termites? Is this project feasible in the real world?

SOURCE: “Two-mile high termite nest proposed to counter the population challenge”05/05/08
photo courtesy of jonrawlinson , used under this Creative Commons license