Comment by cryptonector
12 hours ago
1. It's hard to capture all the waste heat. If you could run this indoors (but vent outdoors if the fuel is anything other than H2, naturally) then you could use some of the waste heat to heat a building.
2. There are thermovoltaic generators, but they're limited by the need to cool one side of the material. These are typically used in deep space probes that use Pu 240 to power them. To my knowledge thermovoltaic generation is not scalable or practical on Earth at this time.
People use the thermoelectric effect for various "energy harvesting" applications, see
https://www.tegmart.com/wood-stove-thermoelectric-generators...
It's an area where you hear about progress from time to time because the technology could improve if people find materials that have a better ratio of electrical conductivity/thermal conductivity.