THE latest supremely elegant glasshouse at Kew Botanic Gardens has a task different from the others. It keeps plants cool and dry, not warm.

The previous Alpine House reached temperatures of 40C (more than 100F) in summer. The new one, opened yesterday by Michael Palin, is kept cool with the help of motorised blinds that fan out like a peacock’s tail. By sail technology from yachts, the white polyester blinds gracefully open and close in no more than a minute.

The house’s hooped silhouette is distinctly reminiscent of the Duke of Wellington’s hat.

The glasshouse was designed by the award-winning architects Wilkinson Eyre, who were also responsible for the Gateshead Millennium Bridge. They were determined to use natural cooling rather than air conditioning. Jim Eyre explained: “Our concept was for a structure which can generate cool air drawn in partly through ventilation grills around the base and escaping through the ten-metre roof.”

Patrick Bellew, of the environmental engineer Atelier 10, said: “Additional cooling is provided by a system akin to termite mounds, where cooler air is drawn in through an underground chamber. Termites use mud to plug or open vents to keep the core of the mound cool. We use automated flaps.

“Beneath the floor is a concrete labyrinth rather like the hypocaust under a Roman villa but used in reverse — to keep the structure cool not warm. Colder air is drawn through at night to cool the concrete, which in turn chills air drawn through during the day.”

As well as cooling the glass, the cool air blows out through foghorn-like nozzles among the plants, simulating a mountain breeze — a big advance on the refrigerating trays sometimes used to keep Alpine plants cool.

Richard Wilford, the Collections Manager at Kew, said: “Part of our brief to the architects was to provide the maximum possible daylight.”

Low-iron glass has been used, increasing light transmission from 80 per cent to 90 per cent. With the structural engineers Dewhurst Macfarlane, the architects have devised a frameless system of glass cladding, creating a virtually all-transparent surface with glass panes supported by stainless steel rods and clamps.

“The glasshouses erected during the Seventies and Eighties were functional and technically innovative but we wanted also to recapture the romance of the original Victorian Palm House,” Mr Wilford said. “With computer-aided technology it is much easier to produce curving structures.”

Alpine plants are defined as those that grow above the treeline, whether in mountain ranges or towards the poles. By contrast to the big beasts in the Palm House the small plants in the Alpine House are displayed as if they were gems in a jewel box. You need to pause and look closely to appreciate the delicacy and intense colour of the flowers. Plants are brought in from nurseries for display as they begin to flower.

Mr Wilford said: “Watering is done by hand. The needs of each plant have to be judged individually. Sprays would create too much humidity.”

The plants now on display include a blue crocus from Chile that was until recently thought to be extinct; the Chinese hellebore, with pale pink flowers that fade to a creamy green; and some of Kew’s national collection of Juno Irises.

The new Davies Alpine House is named after the main sponsor, Edwin Davies, whose fortune was made from automatic switches for kettles.

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