Physicists look to harvest energy from outer space

Physicists at Harvard’s School of Engineering and Applied Sciences have proposed a method to harvest energy from Earth’s infrared emissions. Because our planet is warm, especially compared to the cold void of space, physicists believe a significant amount of energy is transferred at the border between Earth and space. These particular physicists think that it may be possible to take advantage of this transfer and harvest the energy for our own use.

After the Earth is heated by radiation from the sun, it emits infrared radiation from the surface toward space. If these surface emissions can be captured, they could create a direct current of power. The researchers designed two devices that could capture and convert the emissions. They are similar to the photovoltaic cells of a solar panel but attuned to the infrared spectrum.

The first of these devices is a pair of plates. One plate is held at surface temperature, and the second is placed above it. By cooling the upper plate, and thereby creating a temperature difference, the device can initiate energy emissions. By capturing these emissions, the temperature difference between the plates could be used to generate power.

The second device is a nanoscale device which relies on electronic differences between extremely small diodes and antennas. By taking advantage of electronic differences, the device would convert infrared radiation into usable power. Essentially, the components push current in a direction that excludes some electrons. This causes the excluded electrons to cool, generating a voltage difference. This voltage difference can be harnessed to generate power. This extremely small device can be macroscopically useful by combining a large number of its working units.

The challenge with the second device is the need to develop efficient infrared radiation diodes. Due to nanotechnology research, this efficiency is improving at a very high rate. Additionally, though, researchers are having difficulty starting the diodes, as they perform more effectively with higher volumes of power flowing through the circuit. A lot of additional research into infrared radiation diodes is necessary before these devices can be used.