Sun is the main source of heat, lightand energy. Conventional houses are built in such a way that the components ofthe house shield the internal spaces from sun.
This makes the inhabitants toopt for additional heating and lighting sources. The earthship should has ashape and oriented such that it utilisation of available heat and light energyfrom sun is maximum 7. The Orientation depends mainly depends on Azimuthangle and Solar altitude. Azimuth angle is the angle of the sun from due Northin clockwork direction. Solar altitude refers to the angle ofthe sun relative to the Earth’s horizon. It is measured in degrees 9. Thevalue of the solar altitude varies based on the time of day, the time of yearand the latitude on Earth. Regions close to the equator have a higher solaraltitude than regions near the Earth’s poles.
The sun appears at differentangles at different places on the earth. The sun is at its highest point in thesky on the day called Summer Solstice and lowest point on Winter Solstice.Hence the earthship should be oriented such that it receives maximum light onthe day of Winter Solstice. In Northern Hemisphere the Summer Solstice andWinter Solstice is between 21st and 23rd June and between 20thand 23rd December of every year respectively. At the SouthernHemisphere it is the other way around.
Azimuth angle and solar altitude showsthat in summer the sun is not just higher in the sky but also it moves in awider arc and in winter it moves in smaller arc. Based on the altitude of sunin the noon on the coldest day of the year, the face of the glazing on theearthship is tilted such that it is perpendicular to the sun at its lowestpoint. This is done to decrease the reflection on the glazing and thusincreasing the amount of heat and light entering the ship. The same inclinedangle of the glazing helps to increase the reflection during summerconsiderable and thus keeping it cool inside the ship 7.