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How can Solar Energy be used in a passive way? An important question, since it is the main source of any energy on this planet.The sun shines more or less depending on your geographical location. And there is more than one way to collect and use the solar energy.
On the one hand, Solar Energy can be used passively.
For example, a building can be built in a way that more sunlight than with normal building is let in, and so less electricity or heating is needed.
Passive Solar energy is used since humankind began erecting buildings. The Greek and the Chinese are known to have oriented their buildings to the south to catch the light and warmth.The Romans actually had a “right to light”.
In the Middle Ages there was competition in Europe between the Bishops about who was building the Cathedral with the most light inside. The building took generations, so the bishop who started the project never lived to see the final result.
The famous Cathedral of Chartes in France is a result of the competition with Notre-Dame in Paris.
The “battle” between Bishops and masons was so intense that cathedrals were rebuilt several times to keep up with the newer – read lighter – cathedrals
So from ancient times on buildings were erected according to the sun’s position and built in a way that the sunlight is used optimally for using and storing the energy passively and being light.
Also there are system for passively heating up water by sunlight to save heating energy. In ancient times with warm climate it was enough to let the water heat up in the sun
Today modern technology helps to passively heat up water even in colder climates using a collector.
The technology for building solar optimized buildings improved dramatically in the last decades, from the first MIT solar house from 1940 to modern low energy houses.
These buildings use computers to optimize solar lighting, heating and ventilation systems in an sophisticated package.
The most modern, ultra-low energy buildings are called “Passive House” and need no or nearly no additional energy. Ideally no extra heating system is installed.
Around the world there are about 20.000 passive houses, mostly in Europe.