The Atrium Water Garden at the Sefton Hotel, Douglas Isle of Man has a distinctive and most unusual design which uses nature itself to both ventilate and moderate the internal environment creating comfortable conditions for both hotel guests and garden plants alike.
The glass Atrium does not actually sit on the adjacent roofs as would appear to be the case – rather it sits above them with a ventilation gap down its length on both sides. The high glass roof then acts as a sail and by using often slight changes in the external air pressure due to the differing action of the wind on each side of the atrium (depending on the wind direction at any given moment) forces air in one side and out the other. In the process however, as the external air coming in is cooler than the internal air, it drops into the atrium missing the balconies on the way down. As it warms it rises and is drawn out through the vents on the opposite side. The degree to which this happens is controlled by thermostats linked to the vents.
In addition (and as with the Eden Project) there are also vents at the top and bottom of the Atrium with the amount of air movement here again controlled by thermostats linked to the vents.
The possibility of excessive solar gain at the height of the summer is controlled by both the in-built overhang of the roof, which reduces the total exposed glass, and the intervention of blinds. (An idea first seen in the coliseum of ancient Rome, but which here are connected to motors, solar gain and thermostatic detectors)
On particularly cold nights in the depth of winter, heating vents cut in to avoid damage to the plants, which must not be kept at a temperature below 12 degrees centigrade.
All the rooms facing into the Atrium water garden have their access corridors on the outside, thus adding double skin insulation, whilst the inside is subject to the moderated internal temperatures. As a result, although the hotel was doubled in size in 1999, the increase in costs attributable to heating has been negligible. Nature acts on our behalf to help both the heating and cooling of the building. During the warmer dryer periods of the year the floor of the Atrium garden is also watered more often which helps to adjust the humidity a little, making it more pleasant for both guests and plants.