A Model for Solar Access
The model for the solar envelope is found in the ancient settlements of North America. Here, a thousand years ago, settlements were laid out for solar access. Acoma Pueblo, located on a plateau about 50 miles (80 km) west of modern Albuquerque, New Mex-
Acoma Pueblo:Terraced houses are well designed to absorb the low winter sun and protect from the higher summer sun. (Perspective drawing by Gary S. Shigemura in Energy and Form by Knowles 1974,27.)
Acoma Pueblo:Terraced houses are well designed to absorb the low winter sun and protect from the higher summer sun. (Perspective drawing by Gary S. Shigemura in Energy and Form by Knowles 1974,27.)
- Acoma Pueblo: Low winter sun strikes the south-facing masonry walls most directly; High summer sun strikes the timber-and-reed roof terraces that transmit heat less efficiently.
ico, exemplifies such early planning. Rows of houses are stepped down to the south. Walls are of thick masonry. Roofs and terraces are of timber and reeds, overlaid with a mixture of clay and grass.2
Individual houses at Acoma are well suited to a high-desert climate. The sun's low winter rays strike most directly their south-facing masonry walls where energy is stored during the day, then released to warm inside spaces throughout the cold nights. In contrast, the summer sun passes high overhead, striking most directly the roof-terraces where the sun's energy is less effectively stored. What's more, east and west walls are covered by adjacent houses thus further reducing harmful summertime effects.
A small roadway separates each row of houses. The resulting space between the rows is wide enough so that winter shadows cast by any one row of houses covers only the adjoining roadway. Terraces and heat-storing walls remain exposed to the warming rays of the winter sun. It is this critical relationship of building height to shadow area that presents a model for the solar envelope.
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