Wednesday, December 22, 2010

Davies Alpine House at Kew Gardens

The arched shape of this greenhouse is both a new landmark and a welcoming gesture towards visitors to the Royal Botanic Gardens at Kew (a UNESCO heritage site). In the tradition of the innovative, high-tech glasshouses of Kew, this design provides a balanced, energy-efficient growing climate for Kew's collection of Alpine plants. The height of the two back-to-back arched structures ensures efficient thermal updraught to expel warm air at the top of the structure. A fan-shaped cloth provides protection from sunlight. Underground, air is conducted through a concrete labyrinth where it cools down before being reintroduced at the bottom of the greenhouse.
In the wild, alpines spend the winter dormant. They remain dry and protected from extreme temperatures and the desiccating effect of cold winds by a blanket of snow. Spring arrives rapidly, with melting snow providing moisture for growth and exposing the plants to intense light. The short growing season means plants have to flower and set seed quickly. The Davies Alpine House was designed to create the cool, dry and windy conditions that alpine plants favour, without using energy-intensive air-conditioning and wind pumps. Its architects employed traditional practices and the latest technology to achieve this.

Although the glasshouse is only 16 metres (50 feet) long, its roof reaches ten metres (33 feet) high. This creates a stack effect that draws in cool air through permanent openings on either side and releases warm air through vents in the roof. Meanwhile, a fan blows air through a concrete labyrinth beneath the ground. The air cools on its convoluted journey and is released into the glasshouse through steel pipes. The panes of glass are 12mm thick and have a low iron content which allows over 90 per cent of light through. Meanwhile, fan-like shades on the east and west sides of the glasshouse protect plants from the most intense heat of the summer sun.

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