A city near where I lived had an underground house that looked like this. It was the “house of the future” because of reasons I don’t remember. I passed by it a few years ago, and it looked empty, overgrown and run down.
Get a rice cooker with a steam tray. Make a cup of rice, with frozen veggies in the tray. Spice the rice if you want (a little cumin with pepper slices makes excellent fajitas).
When I was in college I put rice in everything because it disgusted my flatmates. I could cook a meal and repel mooches at the same time.
There’s no such thing as a 100% efficient “engine”. But in this case, since the waste heat is put to use (heating the house), OP thinks there’s a loophole.
But, house would also need to be soundproof. Any noise leaking to the outside is lost energy.