Thermoelectric heat transfer

热电传热

A novel way to heat and cool things

一种新颖的供暖和制冷方式

A new approach to carrying heat around as an electric current

一种通过电流传递热量的新方法


Refrigerators and air-conditioners are old and clunky technology, and represent a field ripe for disruption. They consume a lot of electricity. And they generally rely on chemicals called hydrofluorocarbons which, if they leak into the atmosphere, have a potent greenhouse-warming effect. Buildings’ central-heating systems, meanwhile, are often powered by methane in the form of natural gas, which releases carbon dioxide, another greenhouse gas, when it is burned, and also has a tendency to leak from the pipes that deliver it—which is unfortunate, because methane, too, is a greenhouse gas, and one much more potent than CO2.

电冰箱和空调都是老掉牙的技术，颠覆该领域的时机已成熟。它们消耗大量的电能，通常依靠氢氟碳化物，泄露到大气中会造成巨大的温室效应。建筑物的中央供暖系统一般以天然气形式的甲烷为动力源，燃烧时释放出另一种温室气体二氧化碳，而且输送管道容易发生泄漏，不幸的是甲烷也是一种温室气体，造成的温室效应远比二氧化碳更强。

One potential way of getting around all this might be to exploit what is known as the thermoelectric effect, a means of carrying heat from place to place as an electric current. Thermoelectric circuits can be used either to cool things down, or to heat them up. And a firm called Phononic, based in Durham, North Carolina, has developed a chip which does just that.

解决这类难题的一种潜在方法是利用热电效应，通过电流传递热量，热电回路可被用于冷却或加热物体。位于美国北卡莱罗纳州达勒姆市的Phononic公司为此开发出一种芯片。

The thermoelectric effect was discovered in 1834 by Jean Charles Peltier, a French physicist. It happens in an electrical circuit that includes two materials of different conductivity. A flow of electrons from the more conductive to the less conductive causes cooling. A flow in the other direction causes heating.

1834年，法国物理学家简·查理斯·帕尔贴发现了热电效应。它产生于导电性不同的两种导体组成的回路中，电子从高导电材料流向低导电材料出现降温，反向流动出现升温。

The reason for this is that electrons are able to vibrate more freely when pushed into a conductive material. They thereby transfer energy to their surroundings, warming them. When shunted into a less conductive one, electrons’ vibrations are constrained, and they absorb energy from their surroundings, cooling those surroundings down. An array of thermoelectric circuits built with all the high-conductivity materials facing in one direction and all the low conductivity ones in the other can thus move heat in either direction, by switching the polarity of the current. For reasons buried in the mathematics of quantum physics, the heat thus flowing does so in discrete packages, called phonons. Hence the name of the firm.

原因是电子进入导电材料能够更加自由的振动，将能量传递给周围出现升温。电子流向低导电材料后振动受到限制，吸收周围的能量出现降温。在制造的热电回路阵列中，所有的高导电材料朝一个方向，所有的低导电材料朝另一个方向，通过转换电流的极性可以向任意方向传递热量。由于原因隐藏在量子物理学的运算中，所以热量是以“声子”这种离散包的形式传递的，Phononic公司由此得名。

The thermoelectric effect works best when the conductors involved are actually semiconductors, with bismuth and tin being common choices. Fancy cameras contain simple cooling chips which use these, as do some scientific instruments. But Phononic’s boss, Tony Atti, thinks that is small beer. Using the good offices of Fabrinet, a chipmaker in Thailand, he has started making more sophisticated versions at high volume, using the set of tools and techniques normally employed to etch information-processing circuits onto wafers made of silicon. In this case, though, the wafers are made of bismuth.

热电效应最显著的是半导体，常用铋和锡来制造。高档相机配备的简单制冷芯片就是采用这些材料，某些科学仪器也是如此。但Phononic公司总裁托尼·阿提认为这不算什么，在泰国芯片制造商Fabrinet公司的帮助下，他采用在硅晶圆上蚀刻信息处理电路的工具和技术，开始批量制造更尖端的芯片，但使用的是铋晶圆。

The results are, admittedly, still a long way from something that could heat or cool a building. But they are already finding lucrative employment in applications where space is at a premium. At the moment, the fastest-growing market is cooling the infrared lasers used to fire information-encoding photons through fibre-optic cables, for the long-distance transmission of data. They are also being used, though, in the 5g mobile-phone base stations now starting to blanket street corners, to keep the batteries of electric vehicles at optimal operating temperatures, and as components of the optical-frequency radar-like systems known as lidar, that help guide autonomous vehicles.

不可否认，现有成果距离为建筑物供暖或制冷还有很长的路要走，但他们正在寻找利润丰厚而空间有限的用途。目前增长最快的市场是为红外激光器进行冷却，它被用于通过光纤电缆发送信息加密光子，实现远程数据传输。这些芯片也被用于开始覆盖大街小巷的5g手机基站，以及使电动汽车的蓄电池维持最佳工作温度，还可作为激光雷达的零件，它类似于光频雷达装置，帮助导航无人驾驶汽车。

The crucial question from Mr Atti’s point of view is whether semiconductor-based thermoelectronics can break out of these niches and become more mainstream, in the way that semiconductor-based electronics and lighting have done. In particular, he would like to incorporate heat-pumping chips into buildings, to provide them with integral thermoregulation.

在阿提先生看来，关键问题是基于半导体的热电产品能否突破小众市场，就像基于半导体的电子和照明产品一样成为主流。值得一提的是，他希望在建筑物中安装热泵芯片，提供整体式温度调节。

In their current form, thermoelectric chips are unlikely to replace conventional air conditioning and central heating because they cannot move heat over the distances required to pump it in and out of a building in bulk. But they could nonetheless be used as regulators. Instead of turning a big air-conditioning system on or off, to lower or raise the temperature by the small amounts required to maintain comfort, with all the cost that entails, thermoelectric chips might tweak matters by moving heat around locally.

现阶段的热电芯片不太可能替代常规空调和中央供暖系统，因为建筑物大规模的热量输入和输出需要一定距离，热电芯片无法远距离传递热量，但可以把它作为调温器。为了小幅度升高和降低温度来保持舒适性，而不是开启或关闭大型空调系统，考虑到所有的成本，热电芯片可以通过局部传递热量来微调温度。
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Phononic has already run trials of such local-temperature-tweaking chips in Singapore, in partnership with Temasek, that country’s state-run investment fund. In 2019 sp Group, Singapore’s utility company, installed eight of the firm’s heat pumps, which comprise an array of chips pointed down at people, pumping heat out of the air above them, on the boardwalk on Clarke Quay in the city. Phononic claims the devices lowered the temperature in their vicinity by up to 10°C and, as a bonus, consequently reduced humidity by 15%. If that can be scaled up, it would certainly be a cool result.

Phononic公司已与新加坡的国有投资基金“淡马锡”展开合作，在该国试验了这种局部温度微调芯片。2019年，新加坡公共事业公司SP集团在克拉码头的木板人行道上安装了八台该公司的热泵，它们由大量的芯片构成，居高临下朝向行人，从他们头顶吸走空气中的热量。Phononic公司声称，这些设备能使周围的温度下降10°C，由此带来的好处是湿度减少15%。如果可以扩大规模，必然带来可喜的结果。

原创翻译：龙腾网 http://www.ltaaa.cn 转载请注明出处