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Nicholas Goldsmith and Todd Dalland have been leading the development of tensile structures. Now, working with Kiss + Cathcart, Architects, they have fashioned two structures that provide shelter and harness energy. One of these employs glass panels incorporating thin-film photovoltaic (PV) technologies. (courtesy FTL/Happold) |
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| Lightweight and light-sensitive materials bring buildings into
closer and more fruitful relationships with their environments. Most buildings are stoics, employing sturdy materials to bravely hold out against the ravages of nature and time. But there is also a more Heraclitean architecture that's light, sensitive to wind and weight, and built to work within the flux of natural forces, not merely shut them out. Think of circus tents, which blossom like mushrooms overnight, elephantine hulks with loose sides flapping in the wind; or small Bedouin tents whose forms echo the dunes--airy, collapsible architecture meant to keep pace with, and not be subsumed by, the drifting sands. For 20 years, architects Todd Dalland and Nicholas Goldsmith, partners in New York's FTL/Happold, have asked how the lightness and flexibility embodied in structures like tents might inform the way buildings are designed and made. In projects ranging from labyrinthine white pavilions housing the "7th on Sixth" fashion shows, which seasonally occupy Bryant Park behind the New York Public Library, to enormous cocoon-like buildings that the U.S. Army can transport and deploy wherever needed, FTL has developed the tent vernacular into a versatile and articulate architectural language that complements and may in some cases replace that of conventional building. For example, working with fabric and lightweight materials, FTL designed the Olympic Village for the 1996 Atlanta games, essentially an entire city neighborhood that could not only accommodate hundreds of thousands of people, but could also be disassembled and relocated from city to city along with the games. But portability is far from the only benefit of working with lightweight materials. Even in projects as large as the Olympic Village, FTL's fabric structures retain the quality that gives the rudest tent its great romantic appeal: that of affording comfortable shelter separated from the elements by only a thin, tremulous membrane. FTL draws a distinction between early tents, where fabric was draped loosely or with minimum tension over interior supports, and its own structures, which rely on the tension distributed through tightly stretched fabric to maximize their strength. Nylon, polyester, and other synthetic fabrics can be stretched much tighter than canvas, creating a stronger and more resilient skin. Tension also leads to a wide range of distinctive shapes. Stresses from cables and other supports pull the fabric into thorn-like or web-like points from which their surfaces curve in soft, delicate, and often unusual forms, yielding an architecture that seems to float, hover, breathe. Tensile structures are expressive not only of the nature of the fabric, but also of the forces at work on it. If they sometimes resemble bats' wings, leaves, soap bubbles, spiders' webs, branches, and hills, it's not because they are imitating these things but because they have been shaped in response to their environment, and to relentless wind, rain, and snow. So even though they are made of synthetic fabrics, the membranes seem natural and alive. Their shapes form a language that mediates between the rectilinear geometries of most architecture and the wild, hidden geometries of natural form. This ultrathin barrier separating inside from out is itself expressive of the relationship between culture and nature. At the Finnish Chancery in Washington, D. C., FTL worked with architects Mikko Heikkinen and Markku Komonen to construct an awning for a walkway leading from the back of the building into a patch of woods--expressing a typically Finnish attitude toward nature. The relatively small, gently undulating form has the effect of mediating between the building and the woods around it, somehow linking the verticals in the trees to the steel structure and the green-tinted glass to the leaves--and capturing the cinematic play of light and shadow passing through the limbs of the trees. The small tensile membrane creates a connective tissue drawing the building into its environment, a screen on which all the senses of lightness--ethereality, illumination, and energy--merge. Reconfiguring these elements another way, FTL is breaking ground in a new area of technological development. At the request of Lucy Fellowes, a curator at the Cooper-Hewitt National Design Museum in New York City, Goldsmith has been at work designing two small pavilions for "Under the Sun: An Outdoor Exhibition of Light," which will be held in the museum's garden this summer (the show is scheduled to open on June 21, the summer solstice). Goldsmith liked the idea of creating structures wherein the same surface would both provide shelter and harness energy. To accomplish this, he wanted the pavilions to integrate photovoltaic (PV) panels into their design. PVs are the standard technology for producing active solar energy, that is, converting sunlight into electricity. Since FTL hadn't done very much work with PVs, Goldsmith asked Gregory Kiss to collaborate on the project. Kiss's New York firm, Kiss + Cathcart, Architects, has been exploring ways to combine PV technology with architecture for almost 15 years, and, according to Goldsmith, Kiss is one of very few architects who really understands solar and PV technologies. PVs first came into use in the mid-Sixties, when they were developed as a power source for satellites. The technology takes advantage of the fact that silicon sheds electrons when exposed to sunlight, creating an electrical charge that can be harvested as usable energy. The original equipment for gathering this energy employed either single-crystal silicon cells (sliced from cylindrical silicon crystals) or composite polycrystal cells positioned on electrical conductors in large, flat PV panels, or "arrays." Since the silicon cells are rigid, relatively heavy, and while not exactly brittle, can be damaged fairly easily, the array stabilizes them on a flat surface that can be positioned at an angle to reap maximum benefit from the sun's strongest rays. The PV array became the basic building block for experiments with active solar energy, including attempts to integrate them into buildings as a local energy source. While PV panels looked pretty cool on orbiting satellites--their rigidity and fragility somehow adding to the romance of the satellites' seemingly drifting lightness--when the technology was applied to architecture, the results were almost always awkward, wedge-shaped, self-consciously "solar" buildings dominated by strategically angled PV arrays. The earnest clunkiness of solar architecture did little to endear the technology to most architects, and by the mid-Eighties it had fallen almost completely out of favor. Although many explanations have been given for this fizzling of interest in active solar energy among architects--most prominently President Reagan's slashing of government funding for alternative energy sources at the end of the Arab oil embargo and a shift in the culture toward, as Kiss puts it, "yuppie values"--Kiss cites "ugly buildings" as the deciding factor. "These days, the sort of person experimenting with a PV system is more likely to be a retired submarine captain than an architect," Goldsmith adds. But just at the time architects were abandoning it, the technology began to loosen up. Borrowing a technique developed in the production of silicon chips for the computer industry, manufacturers began producing a new breed of PV panels that employed a thin film of silicon and lightweight conductors fused onto materials such as sheet metal or glass, which can withstand the high temperature necessary to prepare the silicon coating. The first pavilion in the Cooper-Hewitt garden will take advantage of a thin-film PV on a flexible metal substrate, a combination that, so far, is produced by only one manufacturer (Iowa Thin Films). The pavilion is a beautiful, small, sensuously curved tensile structure designed to fulfill Goldsmith's idea of providing both shelter and power. Constructed of a polyester mesh in the shape of two elegant hyperbolic paraboloids (one of the basic building shapes of tensile architecture), the pavilion's membrane both diffuses sunlight into a fine, stippled pattern and allows air to vent. The power is produced by thin-film amorphous-silicon panels on a flexible stainless-steel substrate bonded to a PVC coating on the mesh. The near-seamless integration of the PV panels into the curvilinear form (the regular pattern they create on the meshed surface seems like geometric markings on an unusual animal) evinces the versatility of the advancing technology. A more complete contrast with clumsy solar arrays is hard to imagine. The dispersion of the panels over the pavilion's curved surface also represents a shift in philosophy since the days of the flat PV array. Here, orientation of the panels at various angles allows the structure to harvest energy from all kinds of sunlight, not just the strongest rays. This more democratic approach has become feasible in part because thin-film PVs are far less expensive than crystal PVs. According to Kiss, whereas 30 years ago a single panel cost about $1,000, the price of PVs is now comparable to that of conventional building materials and less than that of a material like granite (they are also approaching standard building-module size). Increased efficiency in the technology has also made it more worthwhile to collect even weaker rays of sunlight. "And they will only continue to become cheaper and more efficient," Kiss says. But more than any technological obstacle, Kiss says, a residual bias harbored by architects stands in the way of progress. "There is still a negative feeling about solar," he explains--that it's "hippie-dippy, not serious." Nevertheless, he sees the spread of solar energy driven by PV technologies as inevitable. Environmental and economic issues (including the cost of electricity in densely populated areas) will increase the demand for this clean and abundant energy source (silicon, by the way, is the second most common element in the Earth's crust). Large corporations like Canon and British Petroleum are researching and pushing the technology, and countless smaller companies are developing it for all kinds of uses: from solar-powered lawn mowers that wander and graze like sheep to automobiles, outdoor lighting, and solar-cooled ice-cream carts. Despite lingering attitudes that it is just too expensive or inefficient, the technology is already quietly becoming part of our environment. It's perhaps most prevalent in calculators and watches, which require so little energy that even a desk lamp can run them. But even the city of New York, not known for heroic feats in the realm of environmental sensitivity, uses remote phones powered by PV panels in Central Park precisely because the technology is so dependable while also being significantly cheaper than digging trenches and laying wires. "It will be everywhere," Kiss says, "and since it will be everywhere, the real question for designers is 'What will it do to the environment visually?' " Designers, he believes, should intervene from the start. He himself has experimented with using the technology as a "sensuous" building material in beautifully curved glass curtain walls incorporating thin-film PVs (notably the SEO Solar Facility in Oppach, Germany, and a renovation to the HEW Building in Hamburg) and by employing it purely as a design element in interiors. One or more such thin-film laminates on glass will be both the material from which the second "Under the Sun" pavilion is built and its means of providing energy. As sunlight enters the translucent, boxy structure, the thin-film PV panels, which range in density from opaque to semitransparent, become design elements themselves, blocking, patterning, and filtering light while simultaneously producing electricity to power an air-conditioning unit keeping things cool within. It's a model for a self-sustainingly cool urban building that still feels open to its environment. Goldsmith and Kiss see great potential for PVs in large cities like New York and Chicago, where electricity is not only expensive, but during summer heat waves, often in short supply. Such cities also have a ready-made infrastructure for gathering solar energy: large buildings with expansive curtain walls. And for office buildings, peak use coincides with peak solar hours. As an alternative, PVs can be used, just as tinted glass is, to filter or deflect sunlight from entering a space, with the obvious advantage of using that same sunlight to create energy for the building's systems rather than "wasting" it and relying on energy generated by outside sources. PVs have come a long way from being a rigid technology that determined the form of buildings to a flexible one that can be integrated with radical new building types, humdrum office buildings, or invisibly into older and even historic buildings. By constructively engaging their environment rather than shutting it out, buildings can not only become more efficient and less polluting, but more open, enjoyable, and somehow more alive. Goldsmith and Kiss are particularly aware both of the role architecture can play in sensitizing people to their environment and of the potential for new materials to enrich the life of buildings by creating a tissue of connectiveness rather than isolation. In place in the Cooper-Hewitt's garden, the pavilions will face true south, taking advantage of the sunlight and allowing the tensile pavilion's main support to serve as the gnomon of a giant sundial. "The streets of New York," Goldsmith explains, "were oriented to run parallel and perpendicular to the city's docks, rather than to true north and south." While the streets edging the garden orient the visitor to the city, the pavilions, Kiss says, "will orient them within the cosmos, creating a larger context of connection to the world." Ted Gachot is a freelance writer based in New York City. |
Keywords:
FTL/Happold, tent, solar energy, PV technology, photovoltaics, solar