Union Arena Becomes First Net-Zero Ice Arena
in United States

By Michael J. Caduto, Harold Mayhew, EJay Bishop

Union Arena’s Rooftop Solar Array. Photo by Robert Wagner.

During a 2020 tour of the energy systems in Woodstock’s Union Arena Community Center, architect Harold (Hal) Mayhew and Executive Director EJay Bishop explained how transforming the facility into North America’s first Net-Zero ice arena required meticulous planning and innovative engineering. During the summer of 2021, Union Arena completed its journey toward becoming the first Net-Zero ice arena in the U.S.—reducing energy consumption by 68% and incorporating 32% renewable energy via an expansive solar array on the arena’s roof to produce the remaining energy needed to operate the facility.

The Net-Zero project has been ongoing for the last six years. In that period of time, all the building mechanical systems have been updated and improved. The list is extensive and includes a new dehumidifier, cooling tower, boiler, digital controls, refrigeration components, a heat recovery system, solar panels, and more.

“You’re always wanting to either heat or cool something,” says Mayhew. “We now move the relative hot and cold energy as needed throughout the facility, integrating all systems together. This saves on total energy consumed when compared to the industry standard that traditional systems utilized when the arena was originally constructed twenty years ago. The mechanical systems now have some new features which make it possible such as modulating furnaces, digital demand-based controls, heat recovery loops and variable speed equipment motors.”

“The ultimate goal is cost reductions by reducing the building’s energy consumption,” Mayhew explains. “Net-Zero cuts operating costs, which in turn decreases costs for people to use the ice, thus making ice time available to more people.” The arena serves over 20,000 users each year and generates some $2.5 million in economic activity in the Woodstock area.

How did a local Woodstock organization lead the way in transforming a building with such high energy demand into the first Net-Zero facility of its kind in the US? The genius of this accomplishment is in not tearing down the structure and rebuilding from scratch; it lies in a long list of solutions that demanded creative engineering and innovation. Here, for the first time, is how Union Arena became Net-Zero: 

  • Added a Heat Recovery System
    • Reuses waste heat generated by the compressors during the ice-making process for domestic hot water, to fill the resurfacer and to melt the ice in the ice melt pit.
    • Reduces energy consumption load on the cooling tower, which saves energy and also directly reduces the amount of heat being ejected into the atmosphere.
  • Replaced the Rooftop Air Handler/Dehumidifier/Space Heater
    • New modulating burners match heat with need more accurately.
    • New demand controller for ventilation to match fresh air with needed fresh air more accurately.
    • New enlarged regeneration wheel recycles heat 70% more effectively.
  • Replaced Digital Controls and Adjusted Setpoints Throughout
    • Allowing for a higher level of control and dependability.
    • Adjusted settings for maximum operational efficiency.
  • Refurbished Backup Manual Controls Throughout
    • Allowing for a higher level of control and dependability.
    • Installed a New Rooftop Cooling Tower with Variable Frequency Drive Motor
      • Matches need with motor speed more accurately for improved efficiency.
    • Installed a New Water Treatment System for Cooling Tower
      • Allowing cooling tower to operate at optimum efficiency.
    • Refurbished the Refrigeration System
      • Refurbished compressors.
      • Replaced and recalibrated sensors, circuits and relays.
      • Added ultra-high-volume filters for more efficient flows.
      • Cleaned out clogged lines.
      • Replaced brine pumps with variable speed driven pumps which significantly reduce the overall building power factor (reduces electrical power spiking).
      • Engineered a New Ductwork Layout
        • Improving efficiency in air disbursement in main area.
        • Improving ice quality by reducing hot and cold spots on ice.
        • Installed New High Efficiency Boiler 
          • Producing the domestic hot water and resurfacer fill water more efficiently.
          • Added Solar PV to the Roof of the Building
            • Generating enough energy to bring the facility to Net-Zero after energy consumption measures were taken.
            • Reducing solar gain on the roof surface due to the shading effect from covering the roof above the main ice rink space with solar panels, and therefore reducing the load on the refrigeration system during summer months and shoulder seasons.
            • Re-Engineered the Electrical Phasing
              • Once all of the major changes had been completed, electrical capacitor(s) were added and tuned to align the electrical phasing again (volts/amps). This makes all the equipment and electrical devices operate better and much more efficiently.

              The world has discovered Union Arena’s innovative and forward-looking Net-Zero project. The Net-Zero team has conducted classes for Efficiency Vermont, hosting other ice arena operators. They served as panel members in a webinar shared nationwide in Canada to create a road map to help Canadian municipalities get to Net-Zero. New York City also contacted Union Arena to study the project, which has been featured in articles published by the Associated Press and the Globe & Mail, and in broadcasts over Radio Canada and VPR.

              To the Union Arena leadership, however, it’s all about serving the local community. “We are one of the only ice rinks that heats the air in the entire rink area,” says Bishop. “Union Arena has always been proud to provide a high-quality experience for our users and guests. In my opinion, Hal’s Net-Zero proposal was probably the best way to obtain financial sustainability and continue that experience. It was a way to control our destiny. As a small town with limited resources and a somewhat finite population, I saw this as an opportunity to enable Union Arena to keep its doors open and continue to be the tremendous community asset it has become.”

              What you can do: 

              • Celebrate Union Arena’s Net-Zero accomplishment by attending the celebration at Union Arena from 4:30-6:00pm on Saturday, October 23, 2021: https://unionarena.org/
              • Let the Town of Woodstock know that you support Net-Zero designs in all new construction and building renovations, including the new Woodstock Union High School & Middle School building that is being planned.


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