Rocket Stove Space Heater, you tube search them.
just found out about these and they seem like they would work great in a ice house or camp hut. there are a few designs and the ones with chimneys would be fine in doors. they hardly use any wood at all and would be free heat. they only uses sticks for wood.
endless hot water, you tube search it.
i watched a guy make endless hot water too using an open version of these and thought if you add the copper coil to the inside of one of these rocket heaters, you could have hot water on demand too. making 180 degree hot water for free.
free heat and free hot water sounds great to me! maybe good for a garage. you wouldn't have to use the hot water hook ups, but i would install them to have the option.
i have no need for one in my folding/flip shanties, but thought i would share with those who might want to try them.