◎ Science and Technology Daily reporter Liu Yuanyuan
"Short track speed skating ended with a total of 9 events, 7 events breaking olympic records, 1 event breaking world records..."
At 10:30 p.m. on February 16, Liu Kai, chief engineer of the ice machine of the National Key R&D Program Science and Technology Winter Olympics Special Project "Ice Machine R&D and Application Demonstration" project, sent WeChat to the reporter of Science and Technology Daily.
During the Beijing Winter Olympics, the Capital Gymnasium hosted two events: figure skating and short track speed skating. Liu Kai, who is on duty in the ice machine room, always pays attention to the news of "breaking records" on the ice rink.
In his view, the record that is constantly being broken on the ice rink is also an affirmation of China's "icemaking" technology. "Breaking records requires time, location, people and people!" Liu Kai spoke with a thick Chongqing accent and said proudly.
Some members of the special "Ice Machine R&D and Application Demonstration" project of the Science and Technology Winter Olympics took photos on the ice scene of the Capital Gymnasium.
Ice machine: the "artifact" behind the construction of artificial ice rinks
"The ice rink of the Winter Olympics, the ice-making process is not like ordinary people imagine, just pour the water on it and it's over." Liu Kai said with a smile.
He explained that there are many steps to making ice: first pour the bottom ice, then spray the ice paint, then cover the ice paint, then draw the lines, and spray the LOGO and so on. Generally spraying a layer of water, only 0.5 mm thick ice can be poured. In this way, layer after layer, a piece of ice rink is poured.
Project team members measure the temperature of the ice surface.
Different competitions also have different requirements for ice rinks. In terms of ice temperature, figure skating generally requires ice surface temperature of -3.5 degrees, so that the ice surface is relatively soft, and the impact of falling ice is not too large after the athlete rotates in the air for three or four weeks. Short-track speed skating generally requires ice surface temperature of -6.7 degrees to -7 degrees, and the ice surface is relatively hard. Too soft, not conducive to the grip of the ice knife; too hard, the ice surface is relatively brittle.
Throughout the ice making process, the ice pourer issues various instructions in the ice rink, and the ice system is the "artifact" behind the scenes, responsible for meeting various stringent requirements.
"High-quality ice surface helps athletes achieve better results, and in addition to the superb skills of the ice makers, the uniformity of the ice surface temperature difference and the uniformity of the soft and hardness determined by the ice making system are the key foundations." Professor Tian Hua, the person in charge of the special "ice machine research and development and application demonstration" project of the Science and Technology Winter Olympics and the school of mechanical engineering of Tianjin University, summed up this.
It can be said that the ice machine is the key to the construction of artificial ice rinks.
"The most environmentally friendly" in the history of the Winter Olympics, the system comprehensive energy saving of more than 50%
The ice-making system of this Winter Olympics has been called "the most environmentally friendly" in the history of the Winter Olympics by the media.
"Judging from the ice machines of the ice rinks of the previous Winter Olympic Games, the main synthetic refrigerant technology such as Freon or ammonia refrigeration technology is used, the former has a serious greenhouse effect problem, and the latter has a safety hazard." Tian Hua said.
The "carbon dioxide transcritical direct cold ice making technology" with carbon dioxide as the refrigerant is considered to be a green, low-carbon, high-efficiency and energy-saving solution, but its technology has always been in the hands of enterprises in Europe and the United States and other countries.
In order to help the Green Winter Olympics and the Winter Olympics of Science and Technology, Ouyue Ice and Snow Investment Management (Beijing) Co., Ltd., Tianjin University and other 8 units have jointly developed, designed and built a carbon dioxide transcritical direct cooling ice unit with independent intellectual property rights through industry-university-research collaboration, and demonstrated and applied it in the ice rink of the Capital Gymnasium.
Carbon dioxide transcritical direct cooling ice making unit with independent intellectual property rights.
Tian Hua told science and technology daily reporter that this program is designed from the four processes of compression, cooling, throttling and evaporation of carbon dioxide ice making system. For example, the use of two-stage compression to achieve "half the effort" of source energy consumption, the use of full apparent heat recovery to recover cooling heat.
"From the key components to the integration of the whole machine, the ice machine has realized domestic design, processing, assembly and operation, especially the water-cooled air cooler is the first application in the world, which effectively solves the engineering problem of the long cooling circuit of the first body, and the comprehensive energy saving of the system of the program exceeds 50%." Tian Hua said.
The ice surface temperature difference is 0.3 degrees, and the ice surface conversion takes only 2 hours
During the Winter Olympics, Japanese figure skater Yusuke Yusuke praised: "I can skate very easily here, jump very high, I like the ice surface of this venue too much." ”
This is inseparable from the blessing of the "Made in China" ice machine.
Project members are in the machine room of the CARBON DIOXIDE transcritical direct cooling system.
"Our ice system better controls the temperature difference on the ice surface." Liu Kai told the Science and Technology Daily reporter that the system can realize that on the 1800 square meter ice rink, the actual ice surface temperature difference is only 0.3 degrees, and the optimal time can reach 0.1 degrees, and the ice surface temperature is very uniform.
Liu Kai said that the ice rink at the previous Winter Olympics did not have such a refined control over ice temperature, and this time at the Beijing Winter Olympics, what kind of ice temperature the waterer needed, the ice making system can accurately provide what kind of ice temperature.
"A French ice pourer experienced our ice machine and thought it was magical." Liu Kai said with a smile.
Carbon dioxide barrel pump unit in ice making system.
It is worth mentioning that due to hosting two events, during the entire Winter Olympic Games, the ice rink of the Capital Stadium needs to be converted 30 times to meet the different needs of figure skating and short track speed skating, sometimes only 3 hours in between.
But that didn't bother the ice-making system behind it.
"The project team made full use of the uniform temperature of carbon dioxide ice, combined with the precision control system and linear cooling strategy, to achieve rapid and efficient ice surface conversion within 2 hours, which is far less than the IOC's 3-hour ice surface conversion requirement." Tian Hua said.
Source: Science and Technology Daily The pictures in the article are provided by the interviewees
Editor: Liu Yiyang
Review: Julie
Final Judge: He Yi