Harvesting renewable energy from Earth???s mid-infrared emissions

From a Publication by: Steven J. Byrnes, Romain Blanchard, and Federico Capasso1

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Significance
Renewable energy can be generated whenever heat flows from a hotter to a colder body. One such flow is from the warm surface of Earth to cold outer space, via infrared thermal radiation.

An emissive energy harvester (EEH) is a device that can generate energy from emitting thermal radiation into the clear sky.

We calculate how much power is thermodynamically available, using a location in Oklahoma as a case study. We discuss two possible ways to make such a device:

A thermal EEH (analogous to solar thermal power generation) and an optoelectronic EEH (analogous to photovoltaic power generation).

For the latter, we propose using a rectifying antenna, and we discuss its operating principles, efficiency limits, system design considerations, and possible technological implementations.

Abstract

It is possible to harvest energy from Earth’s thermal infrared emission into outer space. We calculate the thermodynamic limit for the amount of power available, and as a case study, we plot how this limit varies daily and seasonally in a location in Oklahoma. We discuss two possible ways to make such an emissive energy harvester (EEH): A thermal EEH (analogous to solar thermal power generation) and an optoelectronic EEH (analogous to photovoltaic power generation). For the latter, we propose using an infrared-frequency rectifying antenna, and we discuss its operating principles, efficiency limits, system design considerations, and possible technological implementations.

PNAS Article link: http://www.pnas.org/content/early/2014/02/26/1402036111

This article first appeared on environmentalresearchweb.org and was republished in IOP’s PhysicsWorld.com