It is not like a heat pump at all, it is a thermoelectric material. This has been around for ages. Basically, the thermal gradient across a thermoelectric material causes the flow of charged particles. See some of the links below.
They basically built an efficient heat sink (a material good at cooling itself and anything that it is attached to) that radiates heat from one side of their thermoelectric crystal while keeping the other side at room (or other) temperature. This temperature gradient creates the current that they say can run an LED.
They basically built an efficient heat sink (a material good at cooling itself and anything that it is attached to) that radiates heat from one side of their thermoelectric crystal while keeping the other side at room (or other) temperature. This temperature gradient creates the current that they say can run an LED.
https://en.wikipedia.org/wiki/Thermoelectric_effect
https://www.youtube.com/watch?v=6JH-GgLe1xs