Device that converts heat into electricity

Using metamaterials, scientists are developing a device that can radiate infrared rays at controlled frequencies. They hope that in the future, this device can take advantage of excess heat from manufacturing activities to recycle into electricity.

Similar to visible light rays, infrared rays are also a form of electromagnetic radiation and they carry energy with them. For example, furnaces for smelting iron, steel, metal... are sources of high-power heat radiation and they often use electricity to heat the furnace.

However, due to the low efficiency of the furnace, most of this electricity is converted into heat energy in the form of radiation and is wasted into the environment. Therefore, scientists have come up with a way to recover this wasted heat to convert it into electricity and reuse it for other purposes.

The technique of exploiting thermal radiation to convert it into electricity is called thermophotovoltaics (TPV), which is similar in nature to solar power.

Structure of a TPV device to convert heat energy into electrical energy.

Willie J. Padilla, the study's lead author, describes the nature of the thermal radiation layer: "Because the amount of infrared radiation, or intensity, can be controlled, this new infrared radiation layer could open up a new way to capture and reuse lost heat. There is a lot of interest in reusing waste heat, and our technology could improve this process."

The core element of the technology that Padilla and his students are hoping for is metamaterials. These are man-made materials that do not exist in nature but have some extremely special properties, the essence of which comes from a physical structure that is different from the inherent structure of the original natural material.

Specifically, Padilla's team combined a metamaterial designed specifically for high-performance infrared absorption and emission with microelectromechanical systems (MEMS). This combination resulted in a device whose infrared properties can be rapidly changed on a pixel-by-pixel scale.

Metamaterials with properties "opposite" to conventional materials in nature.

But the most notable point compared to traditional TPV devices of Optica is that it can still change the emitted infrared radiation without any heating or cooling method. Optica can still operate at normal temperature without the supporting radiation range being narrowed like old TPV devices.

This detail allows Optica-based TPV devices to convert more forms of infrared into electricity, from both human body heat and car engine heat, which are quite low compared to the temperatures emitted from furnaces or metal smelters.

The ability to radiate heat at will allows for the creation of thermal "stealth" camouflage layers.

In the future, the team plans to scale up the MEMS layer to 128 x 128 pixels, allowing the device to have many more applications. From converting infrared heat into electricity to hiding infrared radiation and the body or vehicle that creates it, helping soldiers better camouflage themselves from enemy thermal scopes.

According to Khoahoc.tv