Whether it's air conditioning for cooling or refrigerators and other cooling equipment, we require what is known as refrigerants to achieve the cooling effect. Although refrigerant cooling is currently the only available method, it also contributes to environmental pollution, causing the greenhouse effect and contributing to global warming. With the world's increasing focus on environmental protection, there is an urgent need to update and replace refrigerants, making environmentally friendly refrigerants particularly important.

It's widely known that air conditioning not only costs money but also increases greenhouse gas emissions. Recently, in a paper published in the journal Science, Yonggui Yang and Xiaobo Yin from the University of Colorado have presented a possible alternative. The two researchers have invented a film that can cool buildings without refrigerant or electricity. Its cooling effect is quite strong: laying 20 square meters of this film on the roof of an average American home is enough to keep the indoor temperature at 20°C when the outdoor temperature reaches 37°C. The film is based on the already commercialized TPX plastic and costs only 50 cents per square meter.

This new type of film operates on the principle of "radiative cooling," utilizing the property of specific wavelength thermal infrared radiation to pass through Earth's atmosphere unimpeded and dissipate into space. Therefore, by first converting unwanted heat into infrared radiation of a specific wavelength, it can then be emitted into the universe. The film developed by Yang Ronggui and Yin Xiaobo is made from polymethylpentene, a transparent plastic known as TPX. They incorporate tiny glass microspheres into TPX, draw the product into thin sheets about 50 micrometers thick, and then coat one side with silver. Placed on roofs with the silver-coated side facing down, sunlight is reflected back by the plastic.

The key to this cooling process lies in the glass microspheres. Since temperature change is a dynamic process, all objects are constantly absorbing and emitting heat. The emitted heat usually exists in the form of infrared radiation. By adjusting the diameter of the glass microspheres, we can change the wavelength of the infrared radiation they emit. The building beneath the film, which serves as one of the heat sources for these infrared rays, can then achieve the cooling effect.

This thin film requires only a small amount of electricity to drive the water pipes to transfer heat during practical use. Furthermore, the entire process is automatically completed by the immense temperature difference of 290°C between the Earth's surface and outer space, making it a new form of refrigeration.

This innovative molecular film can cool buildings, eliminating the need for air conditioning, and directly address global warming at its source. Once this film is applied across various industries, solving greenhouse gas emissions will be a matter of course, directly tackling global warming at its root.

Certainly, many have raised doubts that for air conditioners, by adopting new technology and using this film, we can address greenhouse gases at the source. However, is this film unusable for other cooling equipment? As for this concern, there are still researchers exploring new cooling methods.

In the big data era, computer data centers are highly energy-consuming, with cooling being one of the major electrical energy drains. To save on cooling costs, many international internet giants often establish their data centers in cold-weather regions like Ireland. According to IDC's projections, by 2024, data center electricity consumption will account for over 5% of the total societal electricity use, making energy conservation one of the pursuits of data centers.