Thermophotovoltaic energy conversion
Thermophotovoltaic (TPV) energy conversion is a direct conversion process from heat to electricity via photons. A basic thermophotovoltaic system consists of a hot object emitting thermal radiation and a photovoltaic cell similar to a solar cell but tuned to the spectrum being emitted from the hot object.
Source: Wikipedia — Thermophotovoltaic energy conversion (CC BY-SA 4.0)