CHAPTER 21 I PASSIVE DESIGN


atmosphere long distance sun’s rays


large area


earth short distance


small area


sun’s rays Equator


21.04 Latitude: at higher latitudes the sun’s energy is spread over a larger area, and is therefore weaker than if the sun is higher overhead and the energy is concentrated on a smaller area.


Sun position


The position of the sun relative to the earth doesn’t change. It is because of the earth’s orbit around the sun that the sun appears to move in the sky. The ecliptic is the apparent path of the sun in the sky. The position of the sun in the sky is described by two angles: azimuth and altitude.


ecliptic


altitude West South winter solstice


house built facing south


observer’s horizon


equinox East summer solstice 21.05 Sun position: azimuth and altitude angles.  12 azimuth North


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