The objective of passive solar heating systems is to maintain a pleasant interior temperature by storing solar heat inside the structure of the building and releasing it when the sun is not there. South-facing glass and thermal mass are the two main components of passive solar heating since they both collect, store, and disperse heat. The methods for putting such aspects into practice vary.

Direct Benefit

A solar collector, heat absorber, and distribution system make up the real living area. Glass with a south orientation lets solar energy into the home, where it strikes brick walls and floors, absorbing and storing the heat until it is reflected back into the space at night. 

For maximum heat absorption, these thermal mass materials are often black in color. By absorbing energy, the thermal mass also reduces the intensity of the heat during the day. Heat may be stored inside the living area using water containers. 

Contrary to masonry, however, water requires precisely crafted structural support, making it more challenging to incorporate into the design of the structure. A direct gain system uses between 60 and 75 percent of the solar energy that reaches the windows. 

Thermal mass must be protected from the ambient temperature in a direct gain system in order to keep the solar heat from evaporating. When the thermal mass is in direct contact with the ground or with outside air that is cooler than the mass’s intended temperature, heat loss is very likely to occur.

Indirect Benefit

Between the sun and the dwelling area lies thermal mass. The thermal mass absorbs the sunlight that it receives and conducts it by conduction into the living area. 30 to 45 percent of the solar energy that hits the glass next to the thermal mass will be used by the indirect gain mechanism.

A Trombe wall is one of the most popular indirect gain methods. One inch or less in front of the wall’s surface is mounted a single or double sheet of south-facing glass, which is directly behind the thermal mass, which is a 6 to 18-inch thick masonry wall. 

The dark outside surface of the wall absorbs solar heat, which is then stored in the bulk of the wall and radiated into the living area. In the late afternoon or early evening, solar heat passes through the wall and reaches its back surface. Heat is emitted into the room when the ambient temperature falls below that of the wall’s surface.

A thermal storage wall’s operable vents at the top and bottom allow heat to convect between the wall and the glass and into the living area. The living area is heated by radiant heat from the wall when the vents are shut at night.

If you are interested in more articles like this, here’s one about going solar for your home.


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