Cool: Historic Newport Mansion Goes Geothermal

 The Breakers traditionally consumed 20,000 gallons of oil annually for heating. (istock)

The Breakers traditionally consumed 20,000 gallons of oil annually for heating. (istock)

By ecoRI News staff

NEWPORT, R.I. — The Preservation Society of Newport County has stabilized humidity in a large-scale historic structure and reduced the building’s carbon footprint with the installation of a ground-source geothermal system at The Breakers.

The system combines 19th-century engineering and 21st-century technology to create an interior climate conducive to protecting and preserving the mansion’s collections.

The new system, which uses historic heating shafts built into the masonry of the building in the 1890s to circulate modified air to targeted areas, has proven a significant success, according to Trudy Coxe, executive director of The Preservation Society of Newport County.

Despite record-breaking heat and humidity in Rhode Island this summer, interior humidity and temperatures in The Breakers have remained stable and comfortable, Coxe said. In winter the same geothermal system maintains stable temperatures and humidity with minimum additional heating.

Designed by Richard Morris Hunt for Cornelius Vanderbilt II in 1893 and completed in 1895, The Breakers is a 138,000-square-foot National Historic Landmark. Securing the interior climate of the main house was imperative to the long-term protection of this historic site.

Extreme fluctuations of relative humidity threatened the historic building’s architectural finishes and its decorative arts objects. After extensive research and planning, The Preservation Society of Newport County made the decision three years ago to invest in a ground-source geothermal system using 75 in-ground wells with closed-loop piping.

A refrigerant is circulated through the ground, which has a year-round temperature of about 55 degrees Fahrenheit, is warmed, or cooled, to that temperature, and is then used to drive the heating/cooling process in heat pumps.

Historically, The Breakers was heated through the convection of hot air through ducts built into the masonry. The innovation of the geothermal system is its use of the existing infrastructure to supply targeted areas with modified air. Heat pumps supply 15 fan coil units at selected shafts, which condense water out of the supplied air. The dehumidified, chilled, and filtered air travels through ductwork to the shafts above the existing heating coils to supply the rooms.

Return air is delivered back to the fan coils for re-treatment. Since the system design uses the existing infrastructure, there was no need to interfere with the fabric of the building in any significant way, consistent with the secretary of the interior’s “Standards for the Treatment of Historic Properties.”

Since its completion this spring, the geothermal system has already yielded impressive results, according to Coxe. Relative humidity has been recorded in the correct target zones of 40 percent to 60 percent, with temperatures in the low to mid-70s.

Prior to the geothermal installation, The Breakers traditionally consumed 20,000 gallons of oil annually for heating.