Last fall, Louisville Muhammad Ali International Airport (SDF) went live with a geothermal heating, ventilation and air-conditioning system. This innovative technology replaced all traditional HVAC systems that serve the Kentucky airport’s 417,000-square-foot terminal while ongoing replacement of supporting systems continues.
Louisville Regional Airport Authority implemented the geothermal system as part of its commitment to sustainability, and Executive Director Dan Mann and other leaders expect the use of geothermal technology to reduce SDF’s carbon emissions by 80%, improve air quality for passengers and airport employees, reduce ongoing HVAC maintenance and save $400,000 annually in utility costs.
The $21.7 million terminal HVAC enhancement is a key piece in Phase 2 of SDF NEXT, a three-phase capital improvement program that commits about $500 million in airfield and terminal upgrades to improve energy efficiency, increase the use of alternative fuel sources and enhance the overall customer experience. In addition to the new geothermal system, Phase 2 includes complete refurbishment of the mechanical and electrical systems throughout the terminal building as well as upgrades to lighting, fire safety and security technology, baggage handling system improvements and restroom renovations.
| FACTS&FIGURES
Project: Terminal Infrastructure Improvements Location: Louisville Muhammad Ali International Airport, in KY Key Components: Geothermal system; mechanical, electrical, plumbing infrastructure Groundbreaking: Sept. 2021 System Activated: Oct. 2023 Status: Geothermal is 100% operational; updates to duct work & other supporting systems continue Cost: $21.7 million Funding: $10.6 million FAA Voluntary Airport Low Emissions (VALE) grant Serves: 400,000 sq. ft. terminal Wells: 648 Depth: 500 ft. Geothermal Piping: 122.7 miles Baseline Energy Use: 212 EUI Performed Energy Use: 150 EUI Savings: $400,000/year in heating & cooling costs; less maintenance over time Estimated Carbon Footprint Reduction: 80% Mechanical/Electrical/Plumbing Engineering; Construction Manager at Risk: CMTA Airfield Ramp Design: HNTB Key Benefits: Reduced energy consumption & costs; increased flow of outside air for healthier, more comfortable indoor environment Ancillary Benefit: Geothermal well field is sized for future expansion of terminal |
Phase 1 of SDF NEXT delivered seven projects, including an Airport Operations Command Center, security upgrades and a
new rental car facility. Phase 3 will focus on exterior terminal upgrades, an expanded security checkpoint and a new Federal Inspection Station.
Taking a Beat
In 2018, when the airport was updating its Master Plan, CMTA conducted a full assessment of the Jerry E. Abramson Terminal, including a detailed examination and analysis of the existing building systems. “All of our mechanical systems were fully depreciated,” reports Mann.
Initially, the airport’s plan was for a traditional HVAC system replacement, one-for-one. However, the COVID-19 pandemic slowed the planning process and provided the team time to reflect. “We started thinking about what we could do better in the terminal building,” recalls Brian Sinnwell, chief operating officer at SDF. In this case, “better” meant improving sustainability, saving energy, decreasing energy costs and enhancing air quality.
Looking for a more creative and sustainable HVAC strategy made perfect sense with the airport’s existing system reaching the end of its useful life just as the pandemic prompted more discussion about indoor quality, Sinnwell explains.
To find a better way, the airport partnered with mechanical/electrical/plumbing engineering firm CMTA, a company with extensive experience in sustainable energy that has installed more than 6,500 miles of geothermal infrastructure. Bryan Burke, CMTA’s design team project manager and an electrical engineer based at the firm’s Louisville headquarters, explains that geothermal is a renewable and more sustainable technology to replace SDF’s conventional HVAC systems. The clean, reliable and renewable geothermal energy will reduce the airport’s reliance on fossil fuels and decrease its carbon footprint by 80%, Burke adds. The new HVAC system also increases the amount of outside air that is circulated through the terminal—increasing indoor air quality and improving passenger comfort.
Geothermal technology works by using the earth’s natural temperature control capabilities to heat water in the winter and cool it in the summer, and then distribute it throughout the terminal’s mechanical rooms. For air conditioning, water circulates through pipes and absorbs heat from inside the terminal. That water then moves through pipes, and heat is transferred to the ground. Water in the pipes is cooled and moves back into the terminal, pushing cold air.
The geothermal system at SDF includes 648 wells, each drilled 500 feet deep, making it the largest geothermal project at any U.S. airport, according to project officials. Existing hot and chilled water air handling units are being replaced with geothermal heat pumps during the multi-phase project. Removing old systems that require large, loud cooling towers and boilers will create space for future facility expansion.
Testing the Terrain and Financial Viability
Test wells at the 1,500-acre airport confirmed the viability of leveraging geothermal technology, and the system’s longevity and low maintenance costs helped drive the project forward. Sinnwell notes that geothermal is not an available option everywhere, so the test wells were imperative. Geology of the land is a deciding factor, and CMTA used heat transfer calculations to determine that the system would, in fact, be enough to support SDF’s terminal building. “As it turns out, it was absolutely a viable project here,” says Sinnwell.
Initial investments and the expected payback were other factors affecting SDF’s decision to move forward, Mann notes. The airport received $10.6 million from an FAA Voluntary Airport Low Emissions (VALE) grant, which covered the cost of the geothermal well field and piping infrastructure that connects to the terminal building. Created in 2004, VALE helps airports meet their state-related responsibilities outlined in the Clean Air Act.
Burke acknowledges that the initial investment for a geothermal system may sound steep, but those costs are offset quickly with savings from reduced energy consumption. “By the time we’re done here [at SDF], we’ve projected they will have a 40% raw energy reduction from where they started in 2019, ultimately taking the energy usage factor from 212 to 150, which is a pretty significant jump and a very low resultant for an airport terminal.”
That is expected to translate into $400,000 less in operating costs per year. Burke further points out that geothermal systems are resilient and reliable because they are not susceptible to wind and lightening damage like traditional rooftop units.
“LRAA [Louisville Regional Airport Authority] found the value in implementing a sustainable HVAC and electrical system, and, not only that, reap the benefits of all of the energy savings that come along with it and the reduction in carbon footprint,” he summarizes.
The new system’s lifespan is expected to be 20 years longer than a traditional HVAC system, and it is much easier to maintain, Mann notes. Combined with the return on investment, “It all made sense,” he explains.
The airport created nine acres of additional ramp space on top of its geothermal well field.
Net Gains
As the project progresses, airport leaders continue to balance the efficiency gains that ongoing system renovations will deliver with a commitment to maintaining the customer experience. Mann says that finding the right balance takes a lot of effort, but a carefully phased construction process helps ensure operational efficiency and passenger comfort.
“Every bit of the design and construction takes intensive and thoughtful planning,” Burke adds. Coordinating with airport operations is constant; overnight electrical shutdowns are occasionally needed, but kept minimal to keep the project advancing on schedule.
The geothermal field was installed on what Mann describes as basically unusable airside land. After the wells and other infrastructure were complete, crews paved over the site to create much-needed ramp space. The airport’s nine new acres of pavement provide additional space for aircraft parking during the Kentucky Derby and other large events that bring an influx of traffic. The new ramp also provides more room for deicing stations during inclement winter weather.
“We had all the sustainability issues and the efficiencies, but then on top of that, we got pavement that is actually usable for us,” Mann remarks.
With the Phase 1 landside work complete, geothermal is already proving itself to be a viable solution at SDF. “The first phase went really smoothly,” reports Mann.
The challenge is in the ongoing airside work for Phase 2 because the project team has to keep old systems running while installing and activating their replacements—and, importantly, keep passengers comfortable during the switchover period.
“We’ve seen some gains, but we’ll experience the full advantage when the whole building, including those supporting elements, is on all new systems,” Sinnwell says.
In addition to the benefits SDF expects to reap, officials hope to inspire other airports to explore similar ways to decarbonize their operations. Mann’s biggest takeaway from the project is that geothermal is worth exploring for any airport looking to update and upgrade its mechanical systems. “If it’s viable where you live, it’s a great opportunity to improve efficiency and sustainability,” he says.
For Burke, the collaboration between CMTA and the airport drives home the importance of planning, teamwork and phasing to minimize operational disruptions. “It is possible to implement a geothermal system at an active airport without significant cost and timeline implications,” he emphasizes. “It can be done with the right planning and with the right teammate approach.”
As SDF NEXT continues, the capital improvement program is positioning the airport well for the future, notes Mann. “It’s a great upgrade for the customers in all aspects—from the sustainability improvements to the complete look and feel of the terminal.”
