Wood fired hot tub - GIF

[ToolTalkBot]

Wood fired hot tub.




Previously:

How Jacuzzi tubs are made - GIF

[IntheGroove]

Warmish tub...

[BuffaloJohn]

Where is the pump?

[mklotz]

Where is the pump?

Same principle as a put-put boat...

https://en.wikipedia.org/wiki/Pop_pop_boat

[ductape]

Where is the pump?

It doesn't need a mechanical pump. The coil is below the water level, so it is always full. The cooler water at the bottom of the tub flows into the coil, heats up, and flows out of the top of the coil. Also known as thermosiphon.

[nova_robotics]

Thermosiphons are so effective that the Model T Ford used a thermosiphon for the radiator, as in no mechanical pump on the engine to circulate coolant. A number of pre-WW2 aircraft used/attempted it as well.

I accidentally made a thermosiphon in my house when I installed a circulator pump to get the hot water to my upstairs bathroom faster. When you use the upstairs bathroom in my house there's an extra light switch which turns on a tiny pump in my basement. It circulates hot water in a loop so when you turn on the tap you'll have hot water almost immediately instead of waiting a few minutes for the tap to warm up, but you could also turn off the pump to save energy. Turns out the pump was completely unnecessary. That system would circulate like crazy all day long with or without the pump due to the thermosiphoning effect. I installed a spring check in the system to snap shut when the pump was off to prevent that and save power.

[carl blum]

I'm surprised there isn't a surround that stops the heat from just passing through the coils, and a stove pipe with damper to control the heat of the fire. I have a snorkel stove in my hot tub with a stove pipe and damper. It still gets too hot, but is easy to cool down by adding fresh cold water.

This is a cross section from when I replace a rotten end. Stove is 40 years old, the tub is about 15 year old and has had both ends replaced.
Carl.