It reminds me of these https://en.wikipedia.org/wiki/Thermal_wheel https://en.wikipedia.org/wiki/Thermal_wheel they recover heat that would have been lost to ex

It reminds me of these https://en.wikipedia.org/wiki/Thermal_wheel https://en.wikipedia.org/wiki/Thermal_wheel they recover heat that would have been lost to exhaust. They also recover some of the moisture, making them preferable to plate heat exchangers in some situations.