The context of thermophotovoltalics is very interesting - conventional heat-to-electricity engines are limited by Carnot efficiency, which relies on a "cold side" and generally has low theoretical maximum efficiencies. This approach takes any hot emitter heated by any process - fuel burning, solar concentration, nuclear - and extracts electricity directly from the mostly IR photons it emits.
> Here, we present experimental results on a thermophotovoltaic cell with 29.1 ± 0.4% power conversion efficiency at an emitter temperature of 1,207 °C. This is a record for thermophotovoltaic efficiency.
Photovoltaic’s are also limited by Carnot efficiency.
The theory is you can increase the hot side more as you are less limited by mechanical stresses and moving parts. However, the sun’s surface is 5,505°C, so these are always going to have lower efficiency than traditional solar panels. Which are still less efficient than the bets thermal engines.
This also relies on a "cold side" - the thermophotovoltaic cell has to be colder than the IR source or it will emit photons faster than it can absorb them.
You still need to keep the thermophotovoltaic cells cool, it doesn't violate thermodynamics (energy can only be extracted from a temperature differential).
While it looks like you still do, the other advantage is that these are far more efficient than Peltier devices, which tend to be single-digit percentage efficiency.
No, the whole trick with thermal PV is that you harvest the entire range from thermal infrared to near. A vapour will only glow so so in lower reaches of thermal IR range.
The context of thermophotovoltalics is very interesting - conventional heat-to-electricity engines are limited by Carnot efficiency, which relies on a "cold side" and generally has low theoretical maximum efficiencies. This approach takes any hot emitter heated by any process - fuel burning, solar concentration, nuclear - and extracts electricity directly from the mostly IR photons it emits.
> Here, we present experimental results on a thermophotovoltaic cell with 29.1 ± 0.4% power conversion efficiency at an emitter temperature of 1,207 °C. This is a record for thermophotovoltaic efficiency.