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Ecohouse: A Design Guide
1.6. A Yurt of the Turkoman tribe of Iran (Andrews, 1997, drawn by Susan Parker).
You would probably not survive a severe Mongolian winter in a 300 m2 gher with one small brazier fire and ten people. Insulated envelope buildings need constant heating, from a heat source or from other internal gains such as machines and body heat. The yurt works well because its occupants go to bed very early to conserve heat and light, and sleep at night under thick quilts, often with more than one to a bed, saving considerably on heating. Considerations of the thermal performance of building envelopes are covered in Chapter 2.
THE GREENHOUSE Imagine living in a greenhouse. There are no climates in which it would be comfortable. Glass lets in light and, with it, heat. Incoming solar radiation heats us to help keep our internal body temperature at 37°C. It can also overheat us. Once solar radiation has passed through glass it hits a surface in the building and is reflected or re-radiated at a changed wavelength that can no longer pass, in the same way, back out through the glass, so causing the inside of the greenhouse to heat up. This is exactly what is happening with the world’s atmosphere. The short-wave radiation can pass through the clear atmosphere relatively unimpeded. But the long-wave terrestrial radiation emitted by the warm surface of the Earth is partially absorbed by