Environmental Engineering Reference
In-Depth Information
energy), the absorbed radiation does not disappear, but is converted into heat through the
vibration of the atoms in the material.
Notwithstanding certain innovations and improvements, these three techniques -
orientation, glass, and dark surfaces - remain the cornerstones of passive solar heating
to this day. One of the most interesting of recent innovations is the Trombe wall, which
combines all three techniques: a dark, glass-covered wall facing the sun. The solar
radiation, passing through the glass panel, heats the air in the space between the glass and
the black wall. Vents at the top and bottom of the wall allow a natural exchange of air
through convection. By opening additional vents in the outer walls and glass panel, the
Trombe wall can also be used to cool the building in summer (see
Figure 4.15
).
Figure 4.15.
How a Trombe wall works.
Active Solar Heating
In the early years of the twentieth century, an American entrepreneur named William J.
Bailey used the evangelizing slogan “Sunshine, like salvation, is free” to sell his patented
solarheating systemsinCalifornia. Whereas earlier modelsofsolarwaterheaters consisted
of little more than a black rooftop water tank, Bailey's device separated the heating and
storage elements, so that water heated during the day remained warm enough for hot
showers the next morning. Bailey grew rich in a solar heating boom that ended abruptly in
