每日英語跟讀 Ep.K604: Cellulose Film: A Potential Electricity-Free Air Conditioning Alternative
With the increasing impact of climate change, summers are becoming hotter, leading to the widespread use of air conditioning in many Taiwanese households. However, not all homes worldwide have access to such cooling systems. So, what can be done when the heat becomes unbearable? A promising solution may lie in a new type of cellulose material. Researchers from the University of Cambridge have developed an innovative thin film that actually becomes cooler when exposed to direct sunlight. This cellulose-based material shows great potential as an electricity-free alternative to traditional air conditioning systems.
隨著氣候變遷的不斷加劇，夏季變得越來越炎熱，許多台灣家庭廣泛使用冷氣。然而，世界各地並非所有家庭都有冷氣系統。那麼，當天氣變得無法忍受時該怎麼辦？一種具有潛力的解決方案可能就在一種新型的纖維素材料中。劍橋大學的研究人員開發出一種創新的薄膜，當暴露在陽光下時實際上會變得更冷。這種基於纖維素的材料有望成為一種無需電力的傳統冷氣系統的替代品。
The film operates through passive daytime radiative cooling (PDRC), effectively dissipating heat without raising the temperature of the surrounding air. Cellulose is one of the few plant-based compounds capable of achieving PDRC. By extracting "cellulose nanocrystals" (CNC) from sources like wood and other plants, the researchers created a suspension by dispersing CNC in water. Through the process of evaporation, a flexible arrangement of crystals is formed, which can then be coated onto white ethyl cellulose sheets, resulting in a captivating double-layered, rainbow-colored thin film.
該薄膜通過被動日間輻射冷卻（PDRC）運作，有效地散熱而不使周圍空氣的溫度升高。纖維素是少數能夠實現PDRC的植物基化合物之一。研究人員從木材和其他植物來源中提取出"纖維素奈米結晶"（CNC），並將CNC分散在水中，形成一種懸浮液。通過蒸發過程，形成了一種靈活的晶體排列，可以塗在白色乙基纖維素片上，形成一種迷人的雙層彩虹色薄膜。
In 2023, the University of Cambridge researchers showcased this experimental film at the American Chemical Society conference. When subjected to direct sunlight, the film displayed a temperature reduction of approximately 7 ℉ compared to the surrounding air. A square meter of this thin film generates cooling power exceeding 120 watts, which is comparable to the cooling effect provided by an air conditioner in a home without access to external power sources. The widespread application of this material on buildings and vehicles could significantly reduce the reliance on traditional air conditioning units.
2023年，劍橋大學的研究人員在美國化學學會會議上展示了這種實驗性薄膜。在直射陽光下，與周圍空氣相比，薄膜的溫度降低了約7華氏度。每平方米的薄膜產生的冷卻功率超過120瓦，這相當於家中沒有外部電源的冷氣的冷卻效果。如果將這種材料廣泛應用於建築物和車輛上，可以顯著減少對傳統冷氣的依賴。
An interesting characteristic of the cellulose film is its ability to reflect visible light, creating a colorful appearance similar to that of soap bubbles. Unlike other materials, the cellulose film achieves this without the need for additional pigments, as they would hinder the film's PDRC capabilities. This unique feature makes it highly suitable for applications that prioritize aesthetics, such as residential and automotive designs. Furthermore, there is potential for the film to mimic the appearance of wood finishes, expanding its range of applications. This avenue of research represents the team's next focus.
纖維素薄膜的一個有趣特點是它能夠反射可見光，創造出類似於肥皂泡沫的多彩外觀。與其他材料不同，這種纖維素薄膜無需添加額外的顏料即可實現這一效果，因為顏料會影響薄膜的PDRC能力。這種獨特的性質非常適合用在住宅和汽車設計等注重審美的地方。此外，該薄膜還具有模仿木質飾面的潛力，擴大了應用範圍。這是團隊下一個研究方向的重點。
Reference article: https://ccc.technews.tw/2023/06/09/cellulose-electricity-free-air-conditioning/