Could Earth's Infrared Emissions Be a New Renewable Energy Source? 78
Zothecula (1870348) writes "Could it one day be possible to generate electricity from the loss of heat from Earth to outer space? A group of Harvard engineers believe so and have theorized something of a reverse photovoltaic cell to do just this. The key is using the flow of energy away from our planet to generate voltage, rather than using incoming energy as in existing solar technologies."
Power density? (Score:5, Insightful)
Re:Power density? (Score:4, Insightful)
The diurnal mean of the energy emitted is equal to the energy received (otherwise the oceans would quickly boil away).
The difference is that the energy emitted has a much higher entropy than the energy received: solar energy comes from a source with a temperature around 6000 K, i.e. low entropy, Earth emits the same amount of energy at a temperature of around 300 K, i.e. high entropy.
Hence, it is much harder to get any useful work from the emitted than from the received energy.