Chickenslap
Chickenslap
They haven’t considered rate of slap. Significant heat transfer to environment even at 10 slaps per second.
They’re also assuming sea level standard atmospheric conditions. You may need to reduce rate of slap at altitude.
This assumes both have the same amount of heat capacity * mass. A hand with heat insulating gloves would also significantly reduce heat loss.
Better do it in a vacuum though, you’ll lose energy to air resistance