Wind-power, says Daedalus, is a mixed ecological blessing. Even a very windy site crowded with noisy turbines delivers only a modest amount of electrical power, rather unreliably. Much power these days goes to cool and air-condition buildings. Daedalus reckons the wind could do the job directly.

He points out that a guided air-stream can develop a temperature gradient, a fact exploited in the vortex-tube refrigerator. Air blown helically into a cunningly shaped tube divides into a hot stream and a cold one. The power for this thermodynamic feat comes from the motion of the air itself. So, says Daedalus, it should be possible to give a building a subtle aerofoil shape, such that the wind blowing past it cools it by the vortex effect, while discharging the waste heat into a separate stream downwind. Buildings with strange shapes are highly fashionable these day, and not only in Sydney and Bilbao. But could the design be practical? Commercial vortex-tube refrigerators use air at several atmospheres. Even a strong gale efficiently harnessed would produce less than a degree of cooling.

Daedalus is undaunted. He will give his building regenerative cooling. Banks of internal heat-pipes, with their almost infinite effective conductivity, will return the initial cooling to the incoming wind. The next cycle of cooling will be that much greater. This cooling too will be returned to the incoming wind, and so on. When the required degree of cooling has been reached, the heat pipes will be throttled back.

The shape to do all this will be subtle indeed. Daedalus's starting design echoes those chimneys whose helical vanes direct the wind upwards no matter from which direction it blows. The rising vortex will have its greatest cooling effect on the roof, from which heat-pipes will recycle the cold to incoming ground-level air again. By reversing the vanes, the building can intercept the heated airstream instead, thus allowing the wind actively to warm the building. With its large cross-section, the structure will capture far more energy than any turbine; and as a distributed heat pump, it will be able to deliver many joules of heat or cold for every joule of intercepted energy. The instantaneous heating or cooling effect will vary wildly with the gusting of the wind, but the thermal mass of the structure will smooth it out well. Daedalus's wind-conditioned buildings will be a major contribution to ecological engineering.