The National Speed Skating Oval (NSSO, aka the “Ice Ribbon”) is known for being the only newly built venue at the just-completed Beijing Winter Olympics, and for being one of four arenas to use a transcritical CO2 refrigeration system to make ice, a first for the Olympic Games.

Now it has another distinction: the site of a new world record in speed skating and 10 new Olympic speed-skating records.

The world record was set by Nils van der Poel of Sweden in the men’s speed-skating 10,000m race; he also set an Olympic record in the 5,000m race. Irene Schouten of the Netherlands set two speed- skating Olympic records, in the women’s 3,000m and 5,000m. Her countryman Kjeld Nuis set an Olympic mark in the speed skating men’s 1,500m race.

There may well be a connection between the ice made by the transcritical CO2 system and the multitude of new speed-skating records.

“It’s a much different system than in the past. It reacts very differently, and we’re finding a lot of great things with the CO2,” said Mark Messer, speed skating ice maker for this and four previous Winter Olympic Games, as well as Plant Manager, Ice and Facility Specialist for University of Calgary, Canada, in an interview with Reuters. “It’s great for the environment for a start, so that’s great, but it’s very responsive.”

“Everyone was talking about the Ice Ribbon and the quality and the speed of the ice,” said Guy Evon Cloutier, CEO of the CTC Group, an ice-rink consultancy based in China that is part of a consortium with CIMCO Refrigeration, which provided consulting services for the NSSO project.

Notably, the new records were set at a much lower elevation than that experienced at Winter Olympics held in Calgary, and Salt Lake City, Utah (U.S.), where the thinner air provides less resistance for skaters. In fact, Schouten and Nuis broke Olympic records that had been set in Salt Lake City two decades ago.

Because of the COVID-19 pandemic, Messer had less time than at previous Olympics to get the ice at the Ice Ribbon ready for the Games. He was still fine-tuning it as the skaters arrived, and some found it initially too soft, though it improved as the Games got underway. And it turned out to be solid enough to support the slew of record-setting races.

The transcritical CO2 system was a DX (direct expansion) model that circulated CO2 under the ice to create –9°C (5.8°F) temperature. “The ice is very uniform and steady; it doesn’t move – that’s the beauty of DX,” said Cloutier.

The NSSO’s transcritical CO2 system generated 4MW (1.137TR) of cooling capacity at -18°C (0.4°F) SST and 38°C (100°F) SCT, as well as 3MW of heat. The system used six Carrier PowerCO2OL compressor racks, each with six compressors and one adiabatic gas cooler; and it included four CO2 recirculation vessel packages, each with two CO2 pumps, and vessels connected to common suction and common liquid drains. The floor network employed stainless steel (20mm/0.75in) pipe and stainless steel headers sized to the flow rate.

The system was designed by Swedish OEM Green & Cool, and manufactured by Profroid in France; both companies are wholly owned subsidiaries of U.S.-based Carrier. Italian manufacturer Dorin supplied its CD600 and CD400 CO2 compressors for the project.

In China, Qingdao Haier Carrier Refrigeration Equipment Company Ltd., a joint venture established in 2001 by Qingdao, China-based Haier Group and Carrier, implemented  the transcritical CO2  system at the NSSO.

New CO2 showcases needed

While the success of the Ice Ribbon is a “good story,” it would not be practical to try to replicate its technology and design elsewhere, Cloutier noted. “It’s important over the next six months to have new showcases to show the advantages of CO2 and that it can be cost-effective.”

Cloutier expects enthusiasm for CO2 ice-making from the Olympics to carry over to the construction of new ice arenas. He will be working to make that happen with two Chinese companies, including the Beijing Urban Construction Company,  a government-run entity that built many sites at the Olympic Games. “If the price is right, the government will support it big-time,” he said. This would be helped by the development a new national CO2 design and safety standard, which is underway.

There are currently about 200 indoor ice rinks in China, virtually all using f-gas refrigerants. However, the Chinese government is using the Olympics as a platform for expanding winter sports in China, what it calls the “winter dream.” Chinese President Xi Jinping is said to be committed to getting some 300 million people involved in winter sports. Over the next decade, that could result in at least 2,000 new ice rinks, and maybe as many as 5,000, said Cloutier.

“It reacts very differently, and we’re finding a lot of great things with the CO2.”

Mark Messer, , speed skating ice maker at Beijing Olympics

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