How Princeton Day School Reduced Hockey Rink Emissions
When you think of CO₂, does your mind jump to heat? Greenhouse gasses? Global warming? A common misconception is that carbon dioxide is a gas only attributed to heat. However, at Princeton Day School (PDS) the gas is used for quite the opposite. We took the time to reach out to Mr. Robert Clemens, the Director of Facility Operations at PDS, and he provided us with information on their CO₂ CIMCO Chiller which keeps the ice rink frozen in a bio-friendly and water conserving manner.
Also, because of the chiller’s activity, the heat it produces is recycled to dehumidify the rink, solidifying its sustainability. The chiller is essentially an industrial refrigeration system created to boost sustainability, environmental benefits and efficiency. They have already begun to make their way into the NHL as well, used by the Cleveland Monsters and the Columbus Blue Jackets.
The CIMCO Eco Chill cooling system runs on electricity and uses heat recovery from the refrigeration system to move heat from the ice to other systems within the building or outdoors, recycling its waste and decreasing natural gas consumption from the previous HCFC (Hydrochlorofluorocarbon) R-22 model which was 15% less efficient on energy savings. PDS’ model swap is much more beneficial to the atmosphere because of its lack of natural gas emissions, which hurt the environment through global warming. Because the Eco Chill achieves its cooling power through the use of natural refrigerants CO₂ or ammonia, it doesn’t waste materials.
The main contrast between the CO₂ chiller and the common HCFC R-22 similar to what Lawrenceville has is that the R-22 has 1800 times more global warming potential than the CO₂ chiller which translates to a warming effect equal to 2 tons of CO₂. This data expresses just how threatening this older technology is to our climate and why it needs to be swapped out.
En-Roads is a virtual simulator of our current global climate by 2100 and what inputs are causing it. The simulator shows prospective actions we can take to both increase and lower the temperature in the future.
Figure 1: Decreasing electrification costs in En-Roads by 20% and increasing electrically powered systems in buildings decreases the demand for oil and natural gas.
Mr. Robert Clemens at PDS informed us that the model shift for PDS’ ice rink was done knowing that by 2030 all HCFC models would be discontinued via demand of the U.S Environmental Protection Agency. Knowing this, we used the MIT-Climate Interactive En-Roads simulator to study an increase in electrification equipment rates throughout America by about 20% after 2030, thinking that more people would switch to electrically-efficient models like CIMCO.
Clemens says the goal was to improve from their original dehumidification system which utilized natural gas to provide dehumidification to the ice rink. Clemens knew he wanted to avoid using a system that emits more CO2 which is saturated by the waste from current refrigerants. In En-Roads, it’s easy to see how increasing electrical power in buildings helps decrease demand for oils and gasses, thus reducing the amount of greenhouse emissions. PDS, by reducing the CO₂ in our atmosphere, is slowing down the Keeling Curve which predicts 1,500 ppm of CO₂ in our atmosphere by the next century at our current emissions projections, up from historic levels of 280 ppm.
It’s clear to see just how damaging and inconvenient the R-22 models are to our planet, but also cost effectiveness at our school and many other schools and professional programs across the nation. While some schools like PDS are ahead of the game and already moving to the CO2 chiller, the benefits of the switch displayed in graphs from En-Roads encourage a switch for all rinks within the near future.
Works Consulted
Clemens, R. (n.d.). PDS Leads the Way in Sustainable Operations. Retrieved February 24, 2025, from https://www.pds.org/post/~board/news/post/pds-leads-the-way-in-sustainable-operations
Eco Chill. (n.d.). CIMCO — Sustainable Thermal Solutions. Retrieved February 24, 2025, from https://www.cimcorefrigeration.com/industries/recreational-ice-rinks/ice-rink-solutions/recreation—products/eco-chill
En-Roads. (n.d.). En-Roads Climate Interactive. Retrieved February 24, 2025, from https://en-roads.climateinteractive.org/scenario.html?v=25.2.0&p47=5&p50=5&p338=0&p339=0&p341=0&p371=10&p251=1&p366=0.1&p367=0.1&p368=0
