Winter is supposed to be the best season for wind power. Winds are stronger, and since air density increases as the temperature drops, more force is pushing on the blades. But winter also comes with a problem: freezing weather.

甚至光冰也会在风力涡轮机叶片上产生足够的表面粗糙度，以降低它们的空气动力学效率，这减少了他们可以生产的动力量，因为德州2月份的德克萨斯州。

Frequent severe icing can cut a wind farm’s annual energy production by超过20％, costing the industry hundreds of millions of dollars. Power loss isn’t the only problem from icing, either. The uneven way ice forms on blades can create imbalances, causing a turbine’s parts to磨损更快。它还可以诱导导致涡轮机关闭的振动。在极端结冰的情况下，重新启动涡轮机几个小时可能是不可能的。

The solution is obvious: de-ice the blades, or find a way to keep ice from forming in the first place. So far, however, most of thestrategies为了保持冰风力涡轮机刀片来自航空。和飞机翼和风力涡轮机在不同的条件下进行不同地建造并运行。

我是一个aerospace and mechanical engineer, and my colleagues and I have been studyingwind turbine icing physics在过去的10年里，探索better solutions for turbine icing protection。

Not all ice is the same

冰在无处不在。它可能来自降水，云或霜冻。它还以不同的气候以不同的方式冻结。

For example,rime icing当微小的过冷水滴形成时形成，通常发生在具有相对干燥空气和较冷的温度的区域中，在20°F下。这就是我们通常在冬季的Iowa和其他中西部州看到的东西。

Glaze icing与潮湿的空气和温暖的温度有关，并且在东北沿岸常见。这是风力涡轮机叶片最糟糕的冰。它由于其湿润性质而形成复杂的冰形状，这导致更大的功率损失。当北方的冷空气与来自海湾海岸的潮湿的空气相撞时，它也可能在德克萨斯州在德克萨斯州成立。虽然风暴的大多数电力关闭了天然气，煤炭或核, wind turbines also struggled.

Tempests in a wind tunnel

Building a wind power operation that can thrive in icy conditions requires a keen understanding of the underlying physics, both of how ice forms and the performance degradation that results from ice building up on turbine blades.

To explore those forces, we use a special wind tunnel that can demonstrate how ice forms on samples of turbine blades, and fly camera-equipped drones.

Using the结冰研究隧道at Iowa State University, my team has been replicating the complex 3D shapes of ice forming on turbine blade models in different environments to study how they affect the wind and the blades. Ice can create massive气流分离。In airplanes, that’s a dangerous situation that can cause them to stall. In wind turbines, it reduces theirrotation speed and the amount of powerthey can produce.

我们也study wind turbines in operation around the country当他们面临他们最艰难的条件时。

使用配备高分辨率数码相机的无人机，我们可以在80米高的风力涡轮机上悬停在刀片上形成冰后拍摄的照片。与涡轮机的生产数据配对向我们展示了冰是如何影响电力生产的。

虽然冰可以在整个刀片上形成，但在尖端附近找到了更多的冰。经过一个30小时的结冰事件，我们发现冰厚厚。尽管风高，但冰重型涡轮机旋转得多，甚至关闭。涡轮机生产only 20% of their normal power在那个时期。

Keeping ice off blades

There are a few reasons the strategies that effectively keep ice off aircraft wings aren’t as effective for wind turbine blades.

一个是它们由它们制成的材料。虽然飞机翼通常由金属如铝合金制成，但公用尺度的风力涡轮机由聚合物基复合材料制成。金属更有效地传导热量，因此在飞机翼中循环热的基于热的系统更有效。基于聚合物的涡轮叶片也更有可能被覆盖dust and insect collisions，这可以改变刀片表面的平滑度和慢散水从刀片上运行，促进冰形成。

风力涡轮机也更容易遇到冰冻雨和其他低水平，高水分环境，例如海洋喷雾，用于海上风力涡轮机。

Most current wind turbine anti-icing and de-icing methods remove ice buildup through电热or blowing hot air inside. Heating these massive areas, which are many times larger than airplane wings, adds to the cost of the turbine and is inefficient and energy-consuming. Composite-based turbine blades can also be easily damaged by overheating. And there’s another problem: Water from melting ice may simply run back and refreeze elsewhere.

寒冷天气地区的另一种策略是使用surface coatingsthat repel water or prevent ice from sticking. However, none of the coatings has been able to eliminate ice completely, especially in critical regions near the blades’ leading edges.

A better solution

我的团队已经开发出一种新颖的方法es elements of both technologies. By heating just the critical regions—particularly the blades’ leading edges—and using water- and ice-repelling coatings, we were able to reduce the amount of heat needed and the risk of running back water to refreeze over the blade surfaces. The result effectively prevents ice from forming on整个表面涡轮叶片。

In comparison to the conventional brute-force surface-heating methods, our hybrid strategy also used much less power, resulting in up to 80% energy savings. Without ice to slow it down, the turbines can produce more power through the winter.

全世界，nearly 800 gigawatts到目前为止已经安装了风力发电，包括在美国超过110千兆瓦。As the market quickly grows and wind power supplants higher-polluting energy sources, de-icing and ice-proofing strategies are becoming essential.

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惠胡是爱荷华州立大学航空航天工程教授。这篇文章最初出现在The Conversation并在创建公共许可下进行重新售。