New world records will surely be set when Beijing hosts the next Winter Olympics in 2022, but these games are already making history for a different reason. It will be the first time that carbon dioxide (CO2) is used as a climate-friendly refrigerant to create the cooling in several ice rink venues for the Olympic Games. This includes a potentially world record-setting installation of a massive 12,000 square meter speed skating oval. A recent video rightly calls it a signal of China’s commitment to protecting our planet.
Perhaps you’re thinking, “But I thought CO2 was a greenhouse gas that contributes to global warming! How can it be climate-friendly?” It’s a reasonable question. The answer lies in the synthetic chemicals often used for cooling, called hydrofluorocarbons (HFCs), which have a warming impact thousands of times more potent than CO2. By comparison, cooling systems that use CO2 or other natural substances like ammonia are the greenest alternative refrigerants available. CO2 use in ice rinks is growing quickly and is already used in about half the new ice rinks installed in North America.
Sustainability, ice quality, energy efficiency, and refrigerant costs are all factors in the choice of CO2 refrigerant for the Beijing games, according to refrigeration experts consulting with the International Olympics Committee (IOC). The huge new speed skating oval under construction for the games requires high quality ice to minimize friction and maximize speed. “CO2 allows for very precise temperature control and a uniform temperature across the ice, which is imperative for ice quality,” said Wayne Dilk from CIMCO Refrigeration who has been advising the IOC. “Conventional systems using HFCs and glycol have a higher temperature range underneath the ice and even a one or two degrees Farenheit change can make a big difference for high performance athletes.”
The speed skating oval’s system also recovers the waste heat created by the cooling system and recycles it to heat the occupied spaces and provide hot water, which makes the system extremely energy efficient. This heat recovery feature is expected to save over 2 million kilowatt hours of electricity each year, which is equivalent to annual electricity consumption of 240 homes. CO2 systems can often provide all the heating and hot water requirements of an entire ice rink venue, cutting its total energy use in half, thus lowering emissions and costs. Discussing the efficiency benefits of CO2, Art Sutherland from Accent Refrigeration, who also consulted with the IOC said, “CO2 offers efficiency benefits by creating more and higher temperature waste heat than other refrigerants, making it particularly well-suited for this sustainable building design feature. It also takes about 1/8th the horsepower to pump CO2 under the ice when compared to glycol, another major energy saver.”
CO2 refrigerant also costs less than HFC refrigerants. Due to being synthetically produced and patented, HFC-based refrigerants can often cost around fifteen times more per pound than CO2 or ammonia. For a large system like an ice rink that uses several thousands of pounds of refrigerant, these costs add up. The massive speed skating oval for the Beijing games uses about ten times as much cooling as an average ice hockey rink. The choice of CO2 for this one venue signifies an emission reduction equivalent to yearly emissions of 3,900 cars. Summing it up, David Fauser, also from CIMCO, said, “When you put HFC blends up against CO2, I can’t think of even one advantage. CO2 is less expensive, more efficient, non-toxic, and provides better performance.”
It is still an unfortunate reality that many ice rinks are being designed with climate destroying HFCs. In a disappointing contrast with the Beijing Olympics, the National Hockey League recently partnered with a producer of HFCs to promote refrigerants with 600 to 1,400 times the climate impact of CO2. The NHL’s website incorrectly refers to these alternatives as “low-global warming potential” and also claims CO2 cooling is ‘cost prohibitive’. At the same time, it acknowledges that a third of the NHL’s existing rinks use ammonia refrigerant with zero climate impacts.
China’s choice of CO2 for the Beijing games is symbolic of the rapid progress this technology has made over the past several decades, not just in ice rinks but in other cooling sectors like supermarkets as well. CO2 systems have experienced rapid uptake in recent years. In Europe and the US, the number of CO2 systems has increased by more than 60% annually in recent years. With many configurations of both ammonia and CO2 systems available for both new and replacement equipment, it is becoming increasingly clear that using any HFCs in ice rinks going forward can no longer be justified.
Photo Credit: Arne Müseler / arne-mueseler.com / CC-BY-SA-3.0