The Sundwellings Project: Passive Solar Cabins

By James B. Dekorne
Published on July 1, 1977
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GREENHOUSE UNIT: Warm air from the attached greenhouse rises into the room while cold room air sinks into the greenhouse to be heated. Warmth is stored overnight in the walls and floor of the room . . . which can be closed off from the greenhouse at any time to prevent unwanted heat loss or gain. Note that the greenhouse is dug 2 1/2 feet into the ground to protect it from frost. This design extends the northern New Mexico growing season from 4 to 10 months.
GREENHOUSE UNIT: Warm air from the attached greenhouse rises into the room while cold room air sinks into the greenhouse to be heated. Warmth is stored overnight in the walls and floor of the room . . . which can be closed off from the greenhouse at any time to prevent unwanted heat loss or gain. Note that the greenhouse is dug 2 1/2 feet into the ground to protect it from frost. This design extends the northern New Mexico growing season from 4 to 10 months.
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TROMBE WALL UNIT: Air is heated in the space between the double glass panes and the south adobe wall. It then expands, rises, and enters the room through the adobe wall's upper vents. At the same time, cooler air is drawn from the room through the lower vents and into the Trombe wall space, where it?in turn?is heated, rises, etc. The south wall also stores heat which radiates into the room. Other adobe walls and flagstones store additional warmth.
TROMBE WALL UNIT: Air is heated in the space between the double glass panes and the south adobe wall. It then expands, rises, and enters the room through the adobe wall's upper vents. At the same time, cooler air is drawn from the room through the lower vents and into the Trombe wall space, where it?in turn?is heated, rises, etc. The south wall also stores heat which radiates into the room. Other adobe walls and flagstones store additional warmth.
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DIRECT GAIN UNIT: The simplest of all the solar heating systems used in the project. Large south windows in this house allow sunlight to flood the floor and walls of the main room during the day and the resulting warmth is stored in the adobe and flagstone. Heavy curtains are pulled across the windows at night to prevent heat loss. Eaves over the big windows have been designed to block the high, hot summer sun but admit the rays of the low winter sun.
DIRECT GAIN UNIT: The simplest of all the solar heating systems used in the project. Large south windows in this house allow sunlight to flood the floor and walls of the main room during the day and the resulting warmth is stored in the adobe and flagstone. Heavy curtains are pulled across the windows at night to prevent heat loss. Eaves over the big windows have been designed to block the high, hot summer sun but admit the rays of the low winter sun.
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CONTROL UNIT: This house and all the others in the Sundwellings Project is constructed of adobe (which stores heat well but which is not a good insulator) and has a double north wall filled with 10 inches of pumice to retard heat loss. Pumice is also used for perimeter insulation, and the building's ceiling is insulated with 10 inches of sawdust. Although it contains no special solar features, this is a good example of an energy-conserving building.
CONTROL UNIT: This house and all the others in the Sundwellings Project is constructed of adobe (which stores heat well but which is not a good insulator) and has a double north wall filled with 10 inches of pumice to retard heat loss. Pumice is also used for perimeter insulation, and the building's ceiling is insulated with 10 inches of sawdust. Although it contains no special solar features, this is a good example of an energy-conserving building.

The Sundwellings Project introduces passive solar cabins at a low-cost to the owner and the environment.

About 70 miles north of Santa Fe — set amongst the rugged sandstone cliffs of northern New Mexico — is the Ghost Ranch, an adult study center owned and operated by the United Presbyterian Church. But Ghost Ranch is far more than a church retreat . . . it’s also the site of one of the most important passive solar heating experiments in the U.S. today: the Sundwellings Project.

This program was born roughly three years ago, when a representative of the Four Corners Regional Commission (a federally funded agency administered by the governors of New Mexico, Arizona, Colorado, and Utah) asked New Mexico solar energy pioneer Peter van Dresser (see The Plowboy Interview, MOTHER NO. 35) if he would be interested in receiving grant money for the purpose of designing a solar heating unit that could be retrofitted to mobile homes.

Mr. van Dresser came up with a better idea: “Rather than try to solarize house trailers,” he suggested, “why not spend the money to develop inexpensive, owner-built solar homes appropriate to the human ecology of the local area?” Surprisingly, the Regional Commission spokesman encouraged van Dresser to write up a proposal and told him that — once submitted — his paper would be given a “sympathetic reading”.

To make a long story short, the Four Corners Regional Commission liked what van Dresser had to say and came up with a $34,000 grant calling for Peter to head up a team of architects, engineers, and solar experimenters. Their job: design and supervise the construction of a variety of low-technology solar-heated dwellings made entirely of indigenous materials. (Additional funding — to make the construction phase of the project into a manpower training program — came from the state of New Mexico . . . bringing the total amount of “allocated monies” to $102,000.)

Passive Solar Cabin Building: An Unconventional Beginning

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