WorldWide Drilling Resource

23 AUGUST 2021 WorldWide Drilling Resource® Digging Deep for Education Compiled the Editorial Staff of WorldWide Drilling Resource® Geothermal systems, a rapidly-emerging technology, are being used more frequently in new construction and renovations to heat and cool schools. They heat on cold days with liquid-filled pipes warmed by the earth’s heat, and cool on hot days with a heat pump which extracts heat from the air in the building, transfers it into the liquid in the pipes, and allows it to disperse into the ground. Clean, efficient, and cost-effective, geothermal systems use very little fossil fuels, only those used to generate the electricity running the heat pump itself. Schools usually have available space for geothermal systems, such as adjacent athletic fields or parking lots. Heat pumps, which are easy to maintain and repair, can be located in easily accessible closets or mezzanines with little classroom disruption. Pumping systems are also quiet and do not interfere with instruction. In some instances, previously constructed campuses are being examined to determine if sustainable geothermal systems will be feasible. For example, Cornell University in New York is moving forward with plans to drill a 10,000-foot-deep observatory borehole to explore the viability of using geothermal energy to heat the Ithaca campus. Based on preliminary estimates, the Ithaca campus could be heated by three or four pairs of wells. This borehole will be located on a small facilities parking lot owned by the university and currently used as a contractor staging area. The Cornell University Borehole Observatory (CUBO) will enable researchers to study how much heat can be produced by geothermal energy and to examine its sustainability and any effects. Steve Beyers, the lead earth source heat engineer with Facilities and Campus Services said, “Knowing the precise depths and corresponding temperature, sustainable fluid flow rate, fluid character, and rock type of each target helps us to quantify the benefits, costs, and risks of any future project.” The borehole will be 36 inches in diameter at the surface and will contain progressively smaller casing in progressively thinner holes, all narrowing around a central eight-inch casing extending the full length of the borehole, along with fiber-optic cables to collect and transmit data. Surrounded by five layers of casing and cement to isolate it, no sections will be open below ground. CUBO’s planning and design will take about six months, with construction expected to begin in late summer. Drilling and logging with special tools to collect data and test the subsurface will last about eight months. Many new educational facilities have already been designed with geothermal systems as the heating and cooling source. Frederick Douglass High School in Lexington, Kentucky, is a two-story, 287,125-square-foot facility. A geothermal field under the parking lot consists of 452,300-foot-deep bores and serves as the building’s heat source/sink for the heat pump system. Most of the system’s heat pumps are two-speed so the units can cycle to low speed at part-load condition. A single centralized geothermal pump with a 100% backup pump circulates the geothermal water through the field and building. Three pressure sensors located in remote parts of the piping circuit measure the differential pressure between the heat pump supply and the heat pump return to regulate the variable frequency drive on the main centralized pump. In North Carolina, one school district is planning a new 125,000-square-foot Jones County PK-12 school designed with a geothermal heating and cooling system as an integral element. A Hartford-based architectural firm in Connecticut is designing two elementary schools in Manchester and Mansfield, both of which will use geothermal energy. In Falls Church, Virginia, a geothermal energy system was constructed as part of the new 300,000-square-foot George Mason High School. The 200-well system, with each well more than 500 feet deep, enables the new school to generate energy efficiently for heating and cooling. The school is scheduled to open this year. Twenhofel Middle School in Independence, Kentucky, has geothermal heating and cooling, and uses only half the energy of a typical climate control system. Each classroom can adjust its own temperature independently to maximize comfort. Across the United States, communities are seeing the benefits of geothermal energy resources for educational facilities. Despite the initial investment, geothermal brings with it long-term payoff and lower ongoing operating costs. Schools are uniquely well-positioned to consider this long-term payoff since demand is predictable and relatively consistent. In education settings, the outcomes of initial design decisions are felt for decades to come, and decision-makers are increasingly prepared to consider the long life cycle returns of geothermal systems. Illustration courtesy of Cornell University. GEO Subscriber Snapshot

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