March 19th, 2018 by Steve Hanley on Clean Technica
St. Patrick’s Cathedral on New York’s Fifth Avenue is undergoing a $200 million renovation. Part of that upgrade is a new $35 million geothermal heating and cooling system that replaces the steam boiler and air conditioning system installed nearly 60 years ago. The new system is expected to reduce the cost of heating and cooling the 76,000 square foot cathedral and surrounding campus by about a third, which will also keep about 94,000 kilograms of carbon dioxide out of the skies over New York City every year.
Sustainable And Cost Effective
“It was not only the most sustainable, cost-effective, long-term energy option for the cathedral, but the option that best aligns with the greater good of New York, and not just today, but for generations to come,” Monsignor Robert T. Ritchie, the rector of St. Patrick’s Cathedral, tells the New York Times. Jeffrey Murphy, leader of the team from Murphy Burnham & Buttrick Architects that is overseeing the entire renovation, adds this insight: “If you are an institution that isn’t going to be here for hundreds of years, you may do something less expensive. But if you are interested in sustainability, and you are interested in the long haul, it is a great system.”
The heart of the geothermal system is a collection of 10 wells 8″ in diameter drilled into the bedrock beneath the cathedral. The deepest of the wells goes down 2,200 feet. They feed groundwater at a constant 55º F into a complex jumble of pipes, condensers, and compressors that fit inside the cathedral’s former boiler room. The designers weren’t entirely sure the system would be capable of handling all the heating and cooling needs of the campus, so they included a conventional cooling tower and gas fired furnace as a backup, just in case. But during the year the system has been in place, it has kept up with the hottest summer weather and coldest winter temperatures without assistance.
One of the requirements for the geothermal system was that the outer and inner appearance of the cathedral not be altered in any discernible way. The diocese of New York hopes the switch to geothermal will inspire curators of other historic buildings in the city to follow suit, something they would not be inclined to do if it meant changing the look of their buildings.
Geothermal Is Not For Everyone
Geothermal is not a magic cure for all older buildings, however. The General Theological Seminary, the Episcopal seminary in Chelsea on Manhattan’s west side, began experimenting with a geothermal system in 2005 but ended up using it for only about a quarter of its needs. “If you don’t take into consideration the cost of machinery and the maintenance over an 80-year period, sure, it’s a great deal,” says the Very Rev. Kurt H. Dunkle, the seminary’s dean and president. “But when you take into consideration that the submerged pumps have to be pulled out and maintained and sometimes changed out, for us it made less economic sense than any projection ever described.” Reverend Dunkle’s reservations may sound familiar to those considering the purchase of an electric car. The technology is changing fast and what is state of the art today may be hopelessly out of date in a few years’ time.
An Audacious Plan
New York City is a strong proponent of geothermal systems and uses them in several facilities managed by the city, including the Queens Botanical Garden, the Brooklyn Children’s Museum, and the lion house at the Bronx Zoo. Cornell University has a new technology campus on Roosevelt Island which relies on a geothermal system.
Jeffrey Murphy lauds the diocese for choosing to convert to a geothermal system as part of its renovation program. “I think it really showed a profound sense of optimism and in some ways audaciousness,” he says, “that this venerable institution would consider geothermal technology for their building.” Celebrating traditions that reach back in time more than two thousand years is no reason not to leverage the most modern technology available to protect an historic landmark and serve the needs of the parishioners and visitors to the cathedral while making the surrounding community more sustainable.
Geothermal For Residential Applications
Geothermal technology is not limited to large buildings like St. Patrick’s Cathedral and commercial structures. All the benefits it provides for large energy users apply equally well to residential use as well. Researchers at Oak Ridge National Laboratory say they have invented a new pump for geothermal systems that is 50% more efficient. In fact, new techniques don’t require drilling holes in the earth at all. Instead, trenches as little as 4 feet deep can provide many of the same benefits as groundwater systems. Before installing a new boiler or air conditioning system, you may want to explore the benefits that a residential geothermal system could provide for your own home.
Hat Tip to Steve MacAusland of Rhode Island Interfaith Power & Light.
New York Times article on it: https://www.nytimes.com/2018/03/14/nyregion/st-patricks-cathedral-geothermal.html
Above ground, a 7,855-pipe organ is one of the great splendors of St. Patrick’s Cathedral on Fifth Avenue, the luminous church that will be the heart of the action in New York on St. Patrick’s Day. But hidden below the cathedral’s floor, a new system of pipes just as intricate is a source of equal pride.
A year ago, as part of its nearly $200 million renovation, St. Patrick’s Cathedral launched a state-of-the-art geothermal heating and cooling system to replace its system of steam radiators and 1960s-era air conditioning. Around the cathedral’s perimeter are now 10 wells as deep as 2,200 feet into the Manhattan bedrock, collecting groundwater that helps the church efficiently heat and cool. The cathedral now reaches six times deeper than its Gothic spires soar high.
The system’s thousands of feet of pipes and dozens of pumps are invisible to the five million visitors to the cathedral each year, and that was the point. The trustees of the 138-year-old building, the centerpiece of the Roman Catholic Archdiocese of New York, wanted the church to appear as it always has, even as it was going green.
“It was not only the most sustainable, cost-effective, long-term energy option for the cathedral, but the option that best aligns with the greater good of New York, and not just today, but for generations to come,” said Monsignor Robert T. Ritchie, the rector of St. Patrick’s Cathedral.
Tucked amid the church’s side gardens on East 50th and East 51st Streets are 10 manholes, which cover the eight-inch-wide wells that reach into the bedrock. Hidden behind radiator covers are dozens of fan coils that blow geothermal heat. High above the heads of visitors, in a gallery called the triforium, are 14 larger fan coil units that dump cool air down to sweltering summer visitors. And in the space under the church is a maze of pipes transporting heated and chilled water through the system.
St. Patrick’s standing well geothermal project is the largest ever built in Manhattan, according to its designers. And despite its steep installation cost — about $35 million — the archdiocese is hoping it will set a precedent for other buildings, particularly historical ones.
“If you are an institution that isn’t going to be here for hundreds of years, you may do something less expensive,” said Jeffrey Murphy, who led a team from Murphy Burnham & Buttrick Architects in overseeing the cathedral’s restoration. “But if you are interested in sustainability, and you are interested in the long haul, it is a great system.”
It is also in line with Mayor Bill de Blasio’s vision for a more sustainable New York. In a 2015 report, the Mayor’s Office of Sustainability called on more buildings in New York to consider geothermal power, noting that geothermal systems achieve roughly 25 to 30 percent in energy savings when compared to conventional options.
Sometimes, however, the costs of geothermal can be more than they appear. That was the experience at the General Theological Seminary, the Episcopal seminary in Manhattan’s Chelsea neighborhood, which was among the first to undertake geothermal drilling on a major scale in Manhattan, beginning in about 2005. It ended up scaling back, and now uses geothermal in about a quarter of its space.
“If you don’t take into consideration the cost of machinery and the maintenance over an 80-year period, sure, it’s a great deal,” said the Very Rev. Kurt H. Dunkle, the seminary’s dean and president, who shared the lessons he had learned with St. Patrick’s. “But when you take into consideration that the submerged pumps have to be pulled out and maintained and sometimes changed out, for us it made less economic sense than any projection ever described.”
At the heart of St. Patrick’s new system is its geothermal plant, a tightly packed former boiler room under the church’s campus that is loaded with the pumps, compressors and other equipment that makes the system work.
A computer system automatically determines whether to cool or heat based on thermostats set around the 76,000-square-foot cathedral campus. It can switch various wells on and off, and it can heat some areas while cooling others. That is good news for Cardinal Timothy M. Dolan, New York’s archbishop, who likes to keep the sanctuary “on the cooler side,” said Richard A. Sileo, a lead engineer of the system.
Four separate loops of water propel heat and cooling through the system, Mr. Sileo said. The first loop brings the groundwater, measuring about 55 degrees year round, from the wells into the geothermal plant. The second loop leads to a machine that cools the water down to about 45 degrees in summer, or heats it to about 130 degrees in winter. That water is then piped through the campus and into fan coils scattered around the buildings.
With a system this complex, its designers weren’t sure if it was going to work all the time. What about in a heat wave? Or in a cold snap? So they also installed a traditional cooling tower and a natural gas boiler system as backup.
But the backup has not yet been necessary. Since the geothermal launched in February 2017, it has provided all of the cathedral’s heating and cooling, to the delight of its engineers. The project, designed by the Landmark Facilities Group and P.W. Grosser Consulting, won a 2018 honor from the New York Chapter of the American Council of Engineering Companies.
The archdiocese did not provide estimates for how much money it believes it saved this year, but the engineers estimate that it will reduce energy use over a traditional system by about 30 percent annually. For St. Patrick’s, that totals roughly 94,000 kilograms in carbon dioxide emissions, or about as much created when burning 218 barrels of oil.
According to the mayor’s office, approximately 20 geothermal systems have been installed in New York City in the past five years, but St. Patrick’s is believed to be the largest. There are a handful of city-managed facilities on geothermal, including the Queens Botanical Garden, the Brooklyn Children’s Museum and the Lion House at the Bronx Zoo. And the geothermal plant at Cornell University’s new technology campus on Roosevelt Island can produce even more heating and cooling than at St. Patrick’s, using a closed loop system that is not open to the bedrock.
No other churches in the city are known to have converted to geothermal heating and cooling, but Trinity Church in Boston’s Copley Square has had a geothermal system in place for about 15 years, a spokeswoman said.
In New York, several options were presented to the archdiocese during the renovation, but it determined that geothermal made the most sense, considering aesthetics, longevity, the high cost of a new traditional system, and the desire to do something green, Mr. Murphy said.
“I think it really showed a profound sense of optimism,” he added, “and in some ways audaciousness, that this venerable institution would consider geothermal technology for their building.”
How To Install A Geothermal Heat Pump System
If you are planning to live “off the grid” or just minimize your carbon footprint, you may be thinking about adding solar panels to your roof. Perhaps you want to install a storage battery in your basement as well, so you can charge up for free on sunny days and use that stored electricity for your own personal use later.
Those are good steps to take, but you still have to provide for heating and cooling your home. For that, the most energy efficient system you can buy is a geothermal heat pump. Yes, such a system will cost more than a traditional system powered by oil, propane, natural gas or electricity. But it will more than pay for itself after a few years and put money in your pocket every year thereafter. Savings of 45% compared to a conventional heating or cooling system are typical. It will also add value to your house when it comes time to sell.
What is a geothermal heat pump? It is a system that takes advantage of the fact that the temperature of the earth around your home only varies a few degrees with the seasons. By contrast, an atmospheric heat pump has to deal with ambient temperatures that may be more than 100 degrees in the summer or below zero in the winter. Normal atmospheric heat pumps aren’t very useful at temperatures below freezing, so they need an auxiliary furnace during cold weather.
There are two kinds of geothermal systems. One, called a horizontal system, involves digging a series of trenches about 6 feet deep around your property. Pipes are laid in the trenches then covered over with dirt. Water is circulated through the pipes where it is heated or cooled to the temperature of the earth. Then it is pumped to the heat pump mounted inside the house. In North America, the temperature of the earth is usually between 45 and 72 degrees Fahrenheit.
A vertical system uses a number of holes bored up to 80 feet deep into the ground. Pipes are then installed in the holes and fed through the foundation to the heat pump located inside. In either system, the temperature of the water coming in from outside remains nearly constant throughout the year, allowing the heat pump to operate as efficiently as possible.
Heating and cooling costs are often 50% less with a geothermal heat pump system. And because you already have that marvelous solar energy system on your roof, you can operate the heat pump almost for free, saving even more money. The more you know about a geothermal heat pump system, the more sense — and cents — it may make to install one for your home.
And speaking of saving money, don’t forget to upgrade the windows and insulation in your home to save even more money and reduce your carbon footprint even further. Using modern caulking can cut air infiltration (and energy loss) by another 4%.
With some careful planning, you can reduce the energy need to heat and cool your home significantly. That’s not only good for your wallet, it’s good for the environment as well.
