The Holy Spirit won’t be the only thing moving through the halls of St. Patrick’s Cathedral on Fifth Avenue starting this month. Now in the final phase of its $177 million restoration, the 19th century Gothic Revival church will be soon be throwing the switch on a state-of-the-art geothermal plant that will regulate the temperature of the cathedral and adjoining structures with “increased efficiency and a considerable reduction in CO2 emissions,” the Archdiocese of New York announced last week. The system comprises a network of 10 underground wells, drilled to a depth of up to 2,200 feet, along the north and south sides of the cathedral: four on 51st Street and six on 50th.

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Construction management firm Structure Tone worked in tandem with Murphy, Burnham, & Buttrick Architects, Landmark Facilities Group, Silman, and Langan Engineering, as well as Lane Associates to install a heat pump that extracts thermal energy from the wells, along with a complex of heat exchangers, air handlers, and fan coils to distribute the heat through 76,000 square feet of space.

While most geothermal plants toggle between warming and chilling, the cathedral’s plant splits
the two functions so it can heat or cool different areas simultaneously, the Archdiocese said.

When fully active, the central plant will be capable of producing 2.9 million British thermal units per hour of air conditioning and 3.2 million BTUs of heating.

All of this had to be accomplished with an eye toward historic preservation of the church, whose construction began just before the Civil War.

“At the outset, we evaluated a conventional HVAC system, but determined it would pose too many challenges for this historic building,” Richard A. Sileo, senior engineer with Landmark Facilities Group, said in a statement. “We conducted a feasibility study and found that a geothermal system let us meet our goals with the smallest impact.”

For St. Patrick’s Cathedral, the geothermal plant isn’t just the cleanest, most-cost-effective way of powering the building in the long term; it’s also the most environmentally responsible.

“A consistent ethic of life does not compartmentalize these issues. It prioritizes life and the preservation of life at every level,” said cathedral rector Monsignor Robert T. Ritchie. “One of the most basic ways in which we are called to do so is through responsible stewardship of our natural resources.”

+ Archdiocese of New York

Photos by Marianne Oleary and r351574nc3