问答题
It is officially known as the Swiss Re Tower, or 30 St. Mary Axe. Londoners universally refer to the new 41-story building as "the Gherkin (小黄瓜) ", though it actually looks more like a pine cone. As a typical example of green architecture, what is most remarkable about the building is its energy-efficiency. Thanks to its artful design and some fancy technology, it is expected to consume up to 50% less energy than a comparable conventional office building. Green architecture is changing the way buildings are designed, built and run.
Proponents (支持者) of green architecture argue that the approach has many benefits. In the case of a large office, for example, the combination of green design techniques and clever technology can not only reduce energy consumption and environmental impact, but also reduce running costs, create a more pleasant working environment, improve employees’ health and productivity, reduce legal liability, and boost property values and rental returns.
Green architecture, a term which only came into use in the 1990s, has its origins in the energy crisis of the 1970s, when architects began to question the wisdom of building enclosed glass-and-steel boxes that required massive heating and cooling systems. Early proponents of more energy-efficient architecture included William McDonough, Bruce Fowle and Robert Fox in America, Thomas Herzog in Germany, and Norman Foster and Richard Rogers in Britain.
These forward-looking architects began to explore designs that focused on the long-term environmental impact of maintaining and operating a building. This approach has since been formalized in a number of assessment and rating systems, such as the BREEAM standard introduced in Britain in 1990, and the LEED (Leadership in Energy and Environmental Design) standards developed by the United States Green Building Council (USGBC) starting in 2000. The LEED standards are intended to produce "the world’s greenest and best buildings" by giving developers a straightforward checklist of criteria by which the greenness of a building can be judged. Points are awarded in various categories, from energy use (up to 17 points) to water-efficiency (up to five points) to indoor environment quality (up to 15 points); the total then determines the building’s LEED rating. Extra points can be earned by installing particular features, such as renewable-energy generators or carbon-dioxide monitoring systems. A building that achieves a score "of 39 points earns a "gold" rating; 52 points earns a "platinum" rating. A gold-rated building is estimated to have reduced its environmental impact by 50% compared with an equivalent conventional building, and a platinum-rated building by over 70%. Green is good
As green architecture moves into the mainstream, more green buildings came up. The USGBC says nearly 1,700 buildings in 50 states of America are now seeking LEED certification and 137 have been constructed and certified so far. The 48-story Conde Nast Building at 4 Times Square in New York was one of, the first examples in which green-architecture principles were applied to a large urban office building. In Britain, 70 office buildings constructed during 2003, representing 25% of the total by floor area, met the BREEAM standard. Similar standards have been adopted in New Zealand, Australia and Canada. In China, the Beijing Organizing Committee of the Olympic Games aims to host the first zero-net-emissions games, which will include constructing all buildings and sports locations using green-architecture-principles.
There are many ways to reduce a building’s environmental impact. 30 St. Mary Axe, designed by Foster and .Partners, does so by using natural lighting and ventilation (通风) wherever possible. The facade ( 建筑物正面) consists of two layers of glass (the outer one double-glazed) enclosing a ventilated cavity with computer-controlled blinds. A system of weather sensors on the outside of the building monitors the temperature, wind speed and level of sunlight, closing blinds and opening window panels as necessary. The building’s shape maximizes the use of natural daylight, reducing the need for artificial lighting and providing impressive long-distance views even from deep inside the building.
The highest-profile green building currently on the drawing board is the Freedom Tower, which will be built on the side of the World Trade Centre in New York. The main tower, which will rise 1,776 feet, will include solar panels and a wind farm, the turbines of which are expected to deliver around one megawatt of power, enough to provide up to 20% of the building’s expected demand. Like other green buildings, it will rely on natural light and ventilation, and energy-efficient lighting.
High energy costs, environmental concerns and anxiety about the "sick building syndrome" associated with the sealed-box structures of the 1970s all helped to jump-start the green-architecture movement. But now economics is driving the shift towards greener design.
Why it pays to be green
Going green saves money by reducing long-term energy costs: a survey of 99 green buildings in America found that on average, they use 30% less energy than comparable conventional buildings. So any additional building costs can be recovered quickly: according to the UAGBC, the 2% increase in construction costs required to achieve a LEED gold rating typically pays for itself in lower running costs within two years. The traditional approach of trying to minimize construction costs, by contrast, can lead to higher energy bills and wasted materials.
Energy-saving techniques need not all be exotic as installing coated glass, computer-controlled blinds or photovoltaic (光电的)cells. Michael Crosbie, an architect at Steven Winter Associates, a consultancy based in Norwalk, Connecticut, says builders are now insulating buildings more effectively, in some cases using materials such as recycled paper and fabrics, including old, shredded jeans.
Green buildings can also have less obvious economic benefits. The use of natural daylight in office buildings, for example, as well as reducing energy costs, also seems to make workers more productive. Lockheed Martin, an aerospace firm, found that absenteeism fell by 15% after it move 2,500 employees into a new green building in Sunnyvale, California. Similarly, the use of daylight in shopping complexes appears to increase sales. It also found that students in naturally lit classrooms performed up to 20% better. The increase in productivity paid for the building’s higher construction costs within a year. Green buildings can also reduce legal liabilities for their owners, since they are less likely to give rise to "sick building" lawsuits.
Despite its benefits and its growing popularity, green architecture is still the exception, not the rule, however. The main problem is co-ordination, for green buildings require much more planning by architects, engineers, builders and developers than traditional buildings. But new software is now improving planning by simulating how a building will perform before it is built. Greener by design
In the old days, says Mr. Bernstein, vice-president of the building solutions division at Autodesk, a software company, assessing a building’s environmental impact had to be done with spreadsheets, calculators and informed guessing, and three-dimensional modeling was primarily used to prepare presentations. But now the three-dimensional computer models are being used with sophisticated analytical tools. It’s possible to predict how much energy and water a building will consume, how much material will be needed, and other parameters that determine its LEED certification.
Computers also make possible entirely new designs. 30 St. Mary Axe, for example, could not have been built without a computer model to specify the exact shape of every one of its 5,500 glass panels, or to model the airflow in and around it. Similarly, computer modeling made possible the Avax office building completed in Athens, Greens, in 1998. It has sheaves of glass which open and close automatically, depending on the intensity and angle of the sun, to provide sunlight while preventing the building from overheating. The ventilation system in Pittsburgh’s Convention Centre uses the natural "chimney effect" created by its sweeping roof to draw air through vents by the fiver below, cooling the building without using a single fan.’
This is more than a mere fad, or the use of technology for the sake of it, says Mr. Bernstein. Green architecture will, he suggests, help to reshape the construction industry over the next five years, with ever more innovative, energy-efficient and environmentally friendly buildings. "No one is doing this for fun," he says. "There’s too much at stake.\
chimney effect