NATURAL SOLAR SPACE HEATING – PASSIVE
It began with south facing caves that provided warmth to their inhabitants. This is called “Passive” solar heating because there are no moving parts.
Pictured here is Mesa Verde in Colorado. People that were called the Anasazi inhabited Mesa Verde from approximately 600 to 1300 AD. No one seems to know why they left because it was very comfortable living. It contains about 600 individual dwellings. Some are two stories high. The south facing sandstone walls soak up the sun’s heat in the afternoon and give the heat back to keep the space warm all night.
The Anasazi also carved tunnels to enhance natural ventilation. For details about a new solar heating museum at Mesa Verde, see: energy.gov/eere/success-stories/articles/eere-success-story-mesa-verde-s-new-Museum-showcases-sustainable
DOMESTIC SOLAR SPACE HEATING – PASSIVE
We also have modern forms of passive solar space heating. Here is a drawing of a common design. The overhanging roof on the south side permits winter sunshine and blocks summer sunshine. The floor is made of ceramic or concrete because they are good at storing heat. There are other heat storage possibilities including barrels of water and ceramic or concrete walls. Heat from the floor is transmitted to occupants by radiation and to the surrounding air by conduction. Hot air rises naturally.
DOMESTIC SOLAR SPACE HEATING – ACTIVE
In a large house, it may be necessary to add fans to distribute the warm air. These fans may be controlled manually or automatically
DOMESTIC SOLAR WATER HEATING IN WARM CLIMATES
In climates where water doesn’t freeze, solar water heating can be quite simple. At the turn of the 20th century, many people mounted black painted tanks on their roofs to warm their bath and laundry water.
Later, more complicated systems were developed. Tanks were replaced with black painted copper pipes. These were mounted inside an insulated box with a transparent cover. Water might be pumped through the system or allowed to circulate using the thermosyphon effect. This effect is based on the fact that hot water is lighter weight than cold water and hence rises naturally.
DOMESTIC SOLAR WATER HEATING IN COLD CLIMATES
If water freezes in the winter, a second antifreeze liquid must be added.
This liquid is passed through the outdoor pipes to collect heat. When it is hot, it is brought indoors to a heat exchanger where it heats the bath and laundry water.
An alternative is called a “draw down” system. Here, the water is drawn indoors when the weather is too cold.
Domestic hot water systems are no longer popular except for swimming pools – the price of copper has gone up and the cost of natural gas is low again.
By Bill Butler – Founder of Solar Solutions Central
See solarsolutionscentral.com for energy cost saving products.
Panorama Photo Credit: Cliff Palace at Mesa Verde, by Ben FrantzDale via Creative Commons