Passive solar

From ArticleWorld

Passive solar is a category of techniques used with solar power and strategies that are applied with the purpose of regulating indoor air and domestic water temperatures. This is done through the usage of site features, climate, landscape materials and architectural elements. The main advantage of passive solar systems relies on the smaller costs and the gain observed in living conditions after using it.


The first use of passive solar was observed at the ancient Greek and Romans building techniques. Solar design was being used by them but it took until World War I for the first passive solar houses to be built in Germany. 1940 was the year in which the first such house was built in the United States of America by George F. Keck. It was constructed for Howard Sloan, a real estate developer that operated in the area of Chicago. He built several houses but one day, during the 1933 Century of Progress Exposition in Chicago, he realized that during a sunny winter day the interior provides warm temperatures without any external aid. The next step was the incorporation of South facing windows and special materials with the result being the house that was delivered to Sloan. Keck was not aware of other research being done on the subject. Several builders took in the idea but because of the fact that their houses did not face south and that oil became cheaper, in 1950 the interest in passive solar houses dropped. It was revived in 1973, after the oil crisis.

Solar collection

Based on manufacturer, land and other factors that can be involved, three solar gain techniques have been developed:

  1. Direct Gain – The rays of the sun are allowed directly in the living areas of the house without any attempt to block them. Usually the new home will be built with the windows facing the sun and a high-mass floor is incorporated.
  2. Indirect Gain – Sunlight comes trough the windows, then it hits an intervening material and only after that it gets to the living areas. The rays will thus be held and then redirected.
  3. Isolated Gain – Solar rays are captured and only released when wanted in a passive way. This method is sometimes preferred because it eliminates the risk of over heating and can provide warmth even when the installation can not acquire it from the sun.