Wow, Nick interesting idea. You are not showing your water connections or your pumping arrangement.
Thanks! The outlets of the water connections would be to compression fittings and high temp rubber/silicone hoses that can be dropped into the pool. A bit annoying to model but I have that covered. They'd exit at the top and bottom of the external pipe
If I understand correctly you want to drain a pothole of stagnant water and then use your heater to pump fresh clean (hopefully hot) water in for a homemade hot tub?
I see some possible issues.
1) That metal skin is going to be very hot.
yep! I have plans to add silicone grips to the top lid and have fire gloves to move in case of an emergency. It'd stay put in a drained pothole. There is an idea to have it suspended with wire cable to a rock so there is air flow to the fan and it's out of the way.
2) your pump will need to be just the right flow so your water is at the perfect temp.
Great point. That'll be something to test. A simple 12v submersible pump on the inlet would help prevent any vapor lock/steam.
3) Not sure you will have a sufficient wood quantity to heat and fill a rock hot tub.
Do you mean from just one filling? I imagine I'd need to refill many times depending on the temp of the pool to start.
4) The rock will steal the heat from the water very quickly unless the sun has heated it up.
Fair point, would be something to test with smaller/larger pools since there are so many unknowns.
5) you're running an extension cord to the river for the fan. Water-electricity...
Haha no problem there, right!?
This would be a 12v fan that is rated for ip67. Small waterproof battery pack to run it, so no extension cords down by the river.
Ultimately I could code up a little Arduino to optimize the fan speed, water pump speed and a temp sensor on the water outlet/inlet to get the optimum setup going, but that's for later!
