Santa Fe Arc Continues

The plan of the Arc is relatively simple: split level platforms connected by ramps and sneak stairs. The west level contains the guest bedroom, toilet, shower, spa, utilities, storage, and thermal rock bed. the two levels above that are work spaces connecting to an outdoor deck and bridge. To the east is a sitting areas with a loft canopy above. The sitting area leads to the greenhouse, garden and tool shed. The model shows all the interior walls.The only enclosures are for the toilet and bedroom, which makes air distribution very easy.

This model was still somewhat raw, with some fenestration not yet designed. The cross-axis intersection was more subtle, with dominance changing depending on one's vantage point, which creates an asymmetrical equality. At one point one of the ramps protrudes slightly at the intersection to reveal itself. A photovoltaic array serves as a canopy between the greenhouse and the toolshed.

The entrance at grade on the north which becomes a descending ramp is sheathed in Anazasi stone with small culvert windows aligned to the ramp. Ducting for the hot air system will run under the slab from the greenhouse and south facing collectors to the rock bed for storage. Fans will run off the PVs.

The solar domestic hot water heater will be located above the plumbing core and the pumps will run off the PVs. The cold water entering the system will be preheated in the rock bed, to reduce the size of the collector for reasons of visibility relative to the design covenants. Because the public road is considerably lower than the building, surfaces sloping on the south are foreshortened, which helps meet the intent of the covenants. An air-to-air heat exchanger fresh air system will exhaust stale air in winter with little heat loss penalty. The ceiling on the curved portion will be a woven truss system, which will make reference to the trusses of the dome in the main house. The sections show the relation of the interior platforms to the exterior walls, the ramps, and the progression of spaces along the arc, with various ceiling heights. On the interior the rectilinear element dominates the curved element, but the complexity of the curved element ceiling in contrast to the plain ceiling of the rectilinear element helps balance the two, as the curve can be read through the rectangle.

Backup space heating is by a high-efficiency wood stove, the heated air being fan-distributed to the lower level. This distribution system is separate from the solar/rock bed distribution, and solar and back-up should always be isolated so as not to cross-contaminate. For example: if the wood stove air heats the rock bed in the night, the rock bed's capacity to store solar energy the next day is compromised, as capacity depends on temperature differential.

Here are details of a wall extension containing south facing windows with mirrors which reflect the light down through the wall and into the space, mostly to spread diffused light onto the ceiling. This is preferable to skylights, as it is winter focused, and, therefore, does not need covering in the summer. The sides are canted to reduce the channel wall area and lower horizontal glazing to a minimum. The horizontal glazing is the only area of heat loss, so no insulation is needed above the roof line.