美的创新技术登上Nature，助力空调可持续发展

为助力“双碳“目标，美的大力推进绿色低碳技术布局、研发绿色产品。近年来，空调已成为影响全球气候变化的重要因素，每年产生约20亿吨碳排放，占全球温室气体排放量近4%。美的研发团队一直在不懈努力，不断推出更加高效节能、环境友好、健康舒适的产品解决方案，满足全球消费者对绿色产品的期待。

空调主要通过传递热量来控制温度，换热器是空调系统高效稳定运行的关键所在，通过增大散热面积来实现热量的快速传递。然而，换热器翅片的耐候性不足所导致的空调性能衰减一直是行业无法突破的难题。例如工业排放中的二氧化碳、硫化物、氮氧化物，机动车尾气等酸性物质，以及高温、高湿、盐雾等极端气候环境，特别是在海岛或沿海等紫外线辐射强烈或湿度较大的特殊地区，都会对换热器翅片耐腐蚀性发起巨大的挑战，减少腐蚀的其中一种行业解决方案是使用环氧涂层并增加翅片上涂层的厚度，但会增加空调运行能耗。

美的研发团队基于独创的寿命评估模型与全新的涂层铝箔评价方法，开发了一种含有石墨烯的超薄涂层。相较传统空调翅片，石墨烯翅片具有高导热性特征，热扩散系数提升31%；同时，石墨烯超薄涂层可以实现长效耐腐蚀，能有效解决翅片腐蚀导致的性能衰减问题，实现长效节能。据了解，该研究成果通过Intertek天祥集团加速测试认证，相当于含盐工业环境中20年以上的使用寿命，显著延长了空调服役周期。美的集团空调事业部创新研究院主任李金波介绍道：“这一关键技术的产业化应用，不仅延长了空调的使用寿命，提升了产品的运行节能效率，更有效减少了因金属腐蚀造成的资源浪费与环境污染，对节能减碳具有深远意义。”

目前，这种新型涂层已在多款领先产品中得到广泛应用。例如美的Breezeless系列、Xtreme系列、美的「厨清凉」厨房空调、高端品牌COLMO睿极空调都搭载了此项技术，从材料创新的立足点出发，致力为全球消费者带来健康、可靠、节能的产品体验。

近年来，随着蒙特利尔协议基加利修订案在全球生效，采用更环保、高效的制冷剂成为空调行业的共识。美的家用空调事业部海外产品开发中心主任邢志钢说：“从传统制冷剂R410A转换到R290，可实现每公斤制冷剂的二氧化碳排放量从2000千克降低至0.3千克。”为进一步减少环境影响，美的空调采用了一种采用无氟、无氯、低碳环保的天然制冷剂 R290，相较于其它制冷剂，从空调的生产、使用到报废处置的整个周期，R290在节能环保上的表现都要优于传统制冷剂。在生产上，R290用量更少，更经济；使用过程中，R290具有更高的循环效率，高能效、低能耗；在产品回收后，R290有效避免了产生无法降解的有害物质。这一技术突破使美的空调获得了2020年联合国工业发展组织颁发的“节能环保突出贡献奖”，2023年，美的更成为全球R290销量第一的企业。

目前，全球超过10%的碳排放来自于燃烧化石燃料供暖，在欧洲，近80%的家庭能源消耗来自于供暖。基于这一情况，美的致力于开发可持续的HVAC产品阵容及解决方案，同时，美的聚焦更加丰富、开放的全屋能源管理系统，一站式完成清洁能源储备及控制、电力能耗感知、柔性能源调度与家电智慧响应，推动家庭用能向高效、智能、可靠迈进。

此外，美的通过人工智能和云计算技术开发，完善了对空调变频的更精确控制，实现快速制冷和保持稳定的温度，在有效提高用户舒适度的同时，减少用电量。

美的始终坚定科技研发与科技人才的高投入，在全球十余个国家拥有33个研发中心与40个主要生产基地，专利持有量跻身全球十强，中国Top3，中国民企首位。过去5年，美的集团研发投入接近600亿元。未来，美的将持续科技投入与机制创新，以引领性研究项目与共性技术为抓手，以创新创造驱动，不断提升全球绿色影响力。

以下内容为原文， 链接： https://www. nature.com/articles/d42473-024-00110-6

Air conditioning is becoming crucial for our comfort and survival, but it’s a significant contributor to climate change, with the technology being responsible for an estimated two billion tonnes of carbon dioxide annually, or nearly 4% of global greenhouse emissions. Researchers at one company in China have been tirelessly working to reduce the climate impact of air conditioning, while improving its performance, through award-winning new designs.

Midea researchers have developed an ultra-thin coating containing graphene which enhances the heat exchange efficiency and extends the lifespan of air conditioners.

“Our goal is to provide the best sustainable heating, ventilation and cooling solutions, creating a comfortable and healthy environment, while supporting carbon neutrality and sustainable development goals,” says Jinbo Li, dean of Midea’s Residential Air Conditioning Innovation Research Institute, in Foshan, Guangdong.

Air conditioning controls temperature by moving heat around. A key component is the exchanger, which transfers heat between mediums. This usually involves refrigerant pipelines and fins that exchange heat between the refrigerant fluid and air.

Metal fins increase the surface area of the heat exchanger, which enhances the heat transfer process. However, the thin liquid film on the surface of the fins causes corrosion during use, especially on islands or in coastal areas. The greater the sunlight and humidity, the shorter lifespan, the lower heat exchange efficiency, and higher scrap rates of fins.

Although these fins are coated with a layer of anti-corrosive substance to extend their service life, the coating will reduce thermal conductivity efficiency. Research to solve this has generally looked at limiting corrosion on existing materials, but Xiuling Shang, a material scientist at the institute, thought there was a better way.

Her team has been searching for novel materials, and studying key factors that impact the performance of fins. They collected a large number of used heat exchangers from countries including Australia, Malaysia, and China, and then analysed the failure mechanism of fins and their coatings, identifying key influencing factors such as salt spray, light, temperature and humidity. Then they established models in the laboratory as the foundation for improving fin materials.

From this starting point, Shang wondered: “How can we balance many performances, such as machinability, corrosion resistance and thermal conductivity, to achieve an optimal effect?”

One solution to reduce corrosion is to increase the thickness of the coating on fins, but as this reduces the thermal conductivity of the fins, it also causes a reduction in the efficiency in terms of heat transfer. Shang’s team instead have developed an ultra-thin coating containing graphene. This two-dimensional carbon material has a high specific surface area and high thermal conductivity, making it a good candidate for novel anti-corrosive coatings.

Midea’s tests suggest this coating performs well. Shang says the product has resulted in the thickness of anti-corrosive coatings being reduced by up to one third and she hopes that it could reduce corrosion by up to 90%. It also enhances the heat exchange efficiency and significantly extends the lifespan of the air conditioner. The novel coating is already being used in air conditioning systems in China and globally.

To further reduce environmental impact, Midea has adopted a new more environmentally friendly propane refrigerant. “The switch from the traditional refrigerant, R410A, to R290 significantly reduces equivalent carbon dioxide emissions from 2,000 kilograms to just 0.3 kilograms per kilogram of refrigerant released,” says Zhigang Xing, head of Midea’s overseas air conditioning research and development.

This achievement earned Midea Air Conditioning the ‘Outstanding Contribution to Energy Conservation and Environmental Protection Award’ from the United Nations Industrial Development Organization (UNIDO) in 2020.

UNIDO said it “would like to express its highest appreciation to Midea, for their ongoing efforts to develop, manufacture and introduce to the market residential air conditioners that meet the highest environmental standards.”

Now more than 155 countries and regions around the world have reached a consensus to adopt the Kigali Amendment, accepting that R290 is a valid alternative refrigerant technology route. In 2023, Euromonitor International, a strategic market research group, recognized Midea as the global leader in R290 air conditioner sales.

In search of further opportunities for energy conservation and emission reduction, Midea is exploring new refrigeration technologies, such as radiative cooling materials, that can lower temperature by radiating energy, achieving passive cooling without a refrigerant, says Shang.

The energy efficiency of air conditioning is not only reflected in product design, but also in its use. By leveraging AI and cloud computing, Midea achieves more precise control of air conditioning frequency conversion, realizing rapid cooling and maintaining a stable temperature. “This not only enhances user comfort, but also halves electricity consumption,” says Xing.

Currently, more than 10% of global carbon emissions come from burning fossil fuels for heating. For example, in Europe, nearly 80% of household energy consumption comes from heating. “We hope to change this situation,” Xing said. Researchers are exploring the possibility of replacing fossil fuel heating with new air conditioning solutions, such as air heating technology, which has high energy efficiency and can provide better heating output at the same energy consumption unit.

In addition, Midea is conducting in-depth research on whole house energy management. Xing said, “If we transition to solar photovoltaic power generation and combine it with existing air conditioning technology, we can provide an improved solution for households.”

All of these innovations have been driven by a company culture that encourages bold ideas and collaboration with researchers outside the company, says Li. Midea Group has established 33 R&D centres in 11 countries, forming close technical partnerships with local businesses and institutions.

Founded in 1968, Midea has a workforce of more than 190,000, including 20,000 in the research and development division. Midea Air Conditioning boasts more than 20,000 authorized patents and has been honoured with other awards, including the China Patent Gold Award, one of the most prestigious awards co-organized by the China Intellectual Property Administration and the World Intellectual Property Organization (WIPO).

“We actively engage in discussions with the academic community, hoping to transfer their expertise to industry, innovatively solve problems, and create more energy-efficient and environmentally friendly air conditioning,” Li says.