Energy conversion mechanical to thermal

Motivation: Let's try to create a human powered heat unit which can be used on cold winter days when the sun's heat can't be used and nothing is available to burn. Low temperature (35-40 C) is sufficient for floor heating.
Idea: Let's try to combine the pendulum of Veljko Milković with the heat generated by compressed gas
Let's try to maintain the pendulum's motion with a swinging robot or with some pulling