I used a old car radiator connected just inside the tent and the hoses ran to the outside and eventually going to a larger metal pipe that is laying over a fire pit. The water just went in a closed loop and as it got heated up it would flow through the radiator and back to the fire..
I did have a pop-off value on the the outside leg and every now and then I might get the water hot enough to pop it off...
This used to work like gang busters getting heat inside the tent. Then we would put a battery operated fan behind the radiater to blow air around the tent...
Then in the summer months would do the same idea using a battery operated water pump and pull in water from the creek to go through the radiator and then back to the creek... This would give us cool air to blow around the inside the tent...
A couple of years ago I was in a CABELAs looking at their camping section and saw a similar item for sale using a radiator and a heat exchanger laying across the open fire pit.. I should have applied for a patent way back them haha...
Roy Ken
