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Several character-defining features of the building were kept intact, including the two whimsical tower structures at each end of the horseshoe, the sweeping tile roof, and the rhythm of openings in the exterior masonry wall.

The designers were able to keep the appearance of the small coach house building unchanged on the exterior, but in order to make the main poultry building accommodate offices, some fairly radical changes had to take place. The floors had to be lowered on the ground level, which meant the exterior walls needed to be rebuilt or replaced, and a substantial amount of new space was required.

The architects' scheme placed most of the contemporary additions on the interior of the horseshoe so that the outside could remain visually intact. Rather than imitate the historic fabric of the building, the designers used a contemporary vocabulary to make the new elements contrast with the older structure.

A new entry was located in a flat-roofed bar that connects the two arms of the horseshoe at the open end. Incorporating light-frame steel and glass gives transparency, and the solid-white surfaces of the additions complement the original materials well. The overall effect is a harmonious play between the old and new, with clear distinction between the two.

The tops of the interior extensions are capped with turfed green roofs that are occasionally mowed. Another green feature is a kind of "raised hedge" of trees: a curving row of deciduous trees is being rigorously trained into a shading device on the southern exterior wall.

A Panoply of Strategies

Walking around the site, RES project manager Chris Lawson beams like a new father showing off his children.

"Part of our mission is educational," Lawson says, "and actually this area is not ideal for wind generation; the wind speeds are lower than we'd like for the highest efficiency." Yet the 225-kilowatt turbine can generate more than enough power for the electrical needs of the facility; the remainder is fed into the local grid.

Rather than focusing solely on wind energy, the company chose to explore an integrated range of energy strategies.

Since the farm included seven hectares (17 acres) of land, there was room for five hectares (12 acres) of biomass crop. RES selected Miscanthus giganteus, also called "elephant grass" or "E-grass" — a fast-growing, high-energy-yield perennial grass that can reach up to four meters (13 feet) tall. The crop is harvested, bailed, and allowed to dry until the next heating season.

Once dry, the Miscanthus grass is shredded and burned in a high-efficiency boiler. This hydronic heating source supplies 80 percent of the heat needed for the office building. Burning the plant releases carbon dioxide, a greenhouse gas. These emissions are balanced by the absorption of at least an equal amount of CO₂ by the next grass crop growing in the field.

The grass is stored nearby in a structure that is partly submerged to lessen its visual impact on the historic farm buildings. The roof of the bermed storage building is decked with solar panels that generate electricity and capture heat. A portion of the array consists of PVT panels, a combination of photovoltaic and thermal (hot water) technologies.

Lawson comments that the PVT panels are a compelling option for solar installations in constrained spaces. "Since the photovoltaic and thermal elements have optimal efficiencies at slightly different temperatures, there is a small reduction in the efficiency of the two elements," he says. "But this system allows for both in a small space."

The bulk of the array consists of thermal panels that feed hot water to the main building for winter heat. When there is no heating demand, the excess hot water is diverted into a large underground heat sink. Like a deep swimming pool covered with a floating layer of rigid insulation, the heat store is used to preheat fresh air that is circulated through the offices in cold months. The 1,400-cubic-meter (49,400-cubic-foot) pond is lined but not insulated, allowing the earth to store heat (as long as it remains dry) and to insulate the water.

Near the entry and the historic well, the company drilled a 75-meter- (225-foot-) deep bore hole to tap into the local aquifer to cool the buildings. Groundwater at 12 degrees Celsius (54 degrees Fahrenheit) is extracted and piped into the office space. First it is circulated through condensing coils to dehumidify and cool incoming fresh air. Then, still cool at 15 degrees Celsius (59 degrees Fahrenheit), it is circulated through the offices to cool through convection. Once the cooling capacity of the water has been depleted, it is used to water the Miscanthus crop, where much of it returns to groundwater.

Of course, one of the most important sustainable features of the project is the adaptive reuse of the historic structure. Beaufort Court provides an impressive model for tapping into the embodied energy of an existing building while preserving an important cultural resource.

Although substantial changes were made, overall the place retains a special magic. A wonderfully eccentric building has been brought back to life. And the modern windmill spinning above it serves as a reminder of the exceptional environmental sensitivity of that rebirth.

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Michael Cockram is a freelance writer and designer living in Austin, Texas.

SUBSCRIPTION SAMPLE The Beaufort Court coach house and horseshoe-shaped poultry building were originally built for the Ovaltine Egg Farm. The 1930s structures were recently repurposed by Studio E Architects as offices for Renewable Energy Systems (RES). Photo: Courtesy RES Extra Large Image The turf roofs at Beaufort Court provide insulation and slow stormwater runoff. Photo: Courtesy RES Extra Large Image Beaufort Court's curving interior corridor is filled with light from existing openings and from new clerestory windows along the interior side of the building. Photo: Courtesy RES The solar shed is bermed with earth and covered with solar panels, both photovoltaic and thermal (hot water). Inside, the bales of Miscanthus giganteus grass are dried prior to being burned in a high-efficiency boiler. Photo: Courtesy RES Trees are being trained into a continuous vertical "hedge" that will provide shade on the south side of the building. The windows are also shaded with treated-glass awnings that allow views and daylight while blocking UV radiation. Photo: Courtesy RES Extra Large Image The inner courtyard and turf roof of the recently renovated Beaufort Court as seen from above. Photo: Courtesy RES Diagram drawing illustrating the energy production strategies and systems of Beaufort Court. Image: Courtesy RES Extra Large Image Tinted glass shades minimize solar gain and aid in daylighting at Beaufort Court. Photo: Gordon Kinloch / C-SCAIPE   Click on thumbnail images to view full-size pictures.