CHAPTER 21 I PASSIVE DESIGN Latitude


Geographical latitude is a measure of the position of a point on the earth’s surface above (north 


North Pole normal tangent ellipsoid   Equator


= geocentric latitude  = geographic geodetic latitude


21.02 Latitude: the earth is an ellipsoid (fl attened at the poles).


The radiation from the sun is at its most intense when it falls on the earth’s surface at an angle  as latitude increases and the angle at which the solar radiation strikes the earth’s surface decreases. This angle, called the altitude or sun angle, varies throughout the year. Ireland’s position in the northern hemisphere means that the maximum sun angle ranges from 


bedroom 1


max. summer sun angle (58° to 62°)


kitchen/dining


max. winter sun angle (11° to 15°)


21.03 Maximum sun angle in Ireland varies from winter to summer.  11


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