Camping hot tub. Engineering problem?

[Intrigued again]

TC
Get steel tube from local hydraulic mob ¾” or 20mm and buy el cheapo tube bender from plumbing store, it will work fine. Use a header arrangement it’s about getting the surface area up as much as possible

Or simply add flat bar to your current pipe and fully weld. (not easy with galv)
If you want faster say half the time measure what you have now and add twice as much area (pipe).

And if you want faster add more area

Stainless is an option but you need a lot more tube for the same result it is a terrible U value compared to steel.

Thermo will work the opposite to your setup (hi temp = lower).

Hope I make sense

Good luck

 

[Blacky]

Handy. In effect this is what tc is doing, however rather than using hot water he is using the fire direct. Unless my understanding is incorrect (I'm no engineer). His system is far more efficient. The Wood burn in trying to keep the water barrel boiling would be too high.

We did a similar thing previously. Basically had a bucket of water on the fire, and pumped water directly out of it into the bath. A circular cyphon pumped water from the bath back to the fire water. It was a fine balancing act to get the water temp right.
Mind you this was very "agricultural" developed as "a good idea" after several too many beers. It worked... But so did our jousting stick idea we developed in the hot tub.

They call me an ideas man. Not always a good ideas man, but an ideas man all the same.

Blacky

 

[handyandy]

Handy. In effect this is what tc is doing, however rather than using hot water he is using the fire direct. Unless my understanding is incorrect (I'm no engineer). His system is far more efficient. The Wood burn in trying to keep the water barrel boiling would be too high.

Agree as the steel is getting up to very high temp or at least trying. Water running through would obviously cool it down.

The point of the boiling water is to limit the heat of the water coming into the tub. I assume there are people in the tub when it's running. You could make the immersion more efficient by using more coils of smaller pipe. Copper could be used as not going to melt the copper and keep the spa water sealed away from the boiling water and fire.


We did a similar thing previously. Basically had a bucket of water on the fire, and pumped water directly out of it into the bath. A circular cyphon pumped water from the bath back to the fire water. It was a fine balancing act to get the water temp right.
Mind you this was very "agricultural" developed as "a good idea" after several too many beers. It worked... But so did our jousting stick idea we developed in the hot tub.

They call me an ideas man. Not always a good ideas man, but an ideas man all the same.

Blacky

Most probably having a massive container of boiling water is just as dangerous as you mate stoking the fire.

Cheers

 

[topcropper]

Most probably having a massive container of boiling water is just as dangerous as you mate stoking the fire.

Cheers

Like this?....,




And no, that's not me and my friends. I just found it on the net somewhere.


See ya's.

 

[handyandy]

lol

Biggest danger there is the whole lot falling down.

Mind you how do you get in or out. hahaha

Cheers

 

[The Y-man]

Our old "furo" tub (japanese tub) was basically a similar set up when I was gowing up (yep, predated gas and electrical hot water ) - and yes the thermo siphon was enough to turn the water over BUT ran quite a thick pipe thru a pot belly stove (kind of remember couple of inches diameter?). One thing we were always taught was to NEVER let the water fall below the upper outlet - as it could send scalding steam straight at you.

The Y-man

 

[AlmostBob]

braze pipe joints
brass brazing rod will flux in with zinc in gal coating, flow along pipe threads
leave watertight joints to about 1200 degrees (when brass will melt out of joint)

 

[toony]

Like this?....,




And no, that's not me and my friends. I just found it on the net somewhere.


See ya's.

Look whats for dinner tonight!!!!

 

[redwing]

There's always other options

 

[tobe]

I tried a thermo syphon with black plastic pipe on the shed roof, with either ends in the pool. Did work. was airtight, and the water on the roof was definately much hotter than the pool water. Any ideas? (apart from buying a pool heater and pump....)

By the way, I love the look of those dutch tubs, almost worth the money I reckon.

 

[topcropper]

Any ideas? (apart from buying a pool heater and pump....)

.

The thing I've built is for camping.

Another aim I've got, and if I can get it to work good, would be to heat an outdoor hot tub/spa at home. I don't really like the idea of paying 10K for a new one, and I am a little bit environmentally conscious. It would take a heap of power to heat and it would cost a lot of money to heat, and I realise that like a lot of stuff, boats, etc, you don't use it as much as you think you will.

So I'd build a bigger, non portable water heater. Then buy an old outdoor spa on E-bay or gumtree or some where. They are for sale for bugger all, $1000 for a good one and a few hundred for a rough one. I've even seen em for giveaway if the heater or something else is buggered and if you come and take it away. I've got unlimited and free firewood. Unlimited water. I'd heat the tub with the water heater I build, get it going say on a Friday arvo, we'd use it all weekend, and then just let the water out on Monday. Repeat next month, or when ever you wanted it. So there's be no expensive heater going, no chemicals or chlorine to keep the water clean.

I've even thought about heating the pool? I like burning wood?


See ya's.

 

[topcropper]

There's always other options

Wow! There is a lot of metal in that bucket to heat up before any water would get warm.


See ya's.

 

[HiEquity]

The outlaws on the farm installed a water jacket heater in the top and flue of their JOTUL slow combustion wood heater in the house. Then piped it via thermo siphon into the hot water heater. Except it gets too hot - even with 100s of litres of storage! If you keep a wood fire going in winter in the house, this would be and ideal solution so you don't have to run another fire all or some of the time. As long as you have a thermal blanket on the pool / spa they should stay warm all the time in winter at least. And solar heating in summer with the blanket does the trick if they're in the sun...

Pool / spa needs to be near the house though and you will need to insulate the pipes...

 

[The Fence]

I am a little bit environmentally conscious.


I like burning wood?

Dont think those two comments go together too well....

Must be fallow time eh TC, went past today you must have been in the shed welding this thing?

Might drop in Thursday if you are about. Im down the road doing a bit at levondale.

 

[topcropper]

Dont think those two comments go together too well....

.

Ha ha. Yeah your probably right.

I'll be at Ag-quip tomorrow, should be there Thursday?


See ya's.

 

[topcropper]

The outlaws on the farm installed a water jacket heater in the top and flue of their JOTUL slow combustion wood heater in the house. ...

Not sure about the cities, but around here at least most people 50 years ago or more had a water heater, heated from their slow combustion stoves and using thermo-siphon. They were called 'donkey' heaters for some reason. I vaguely remember them.


See ya's.

 

[redwing]

Don't try this one

 

[The Fence]

Not sure about the cities, but around here at least most people 50 years ago or more had a water heater, heated from their slow combustion stoves and using thermo-siphon. They were called 'donkey' heaters for some reason. I vaguely remember them.

Yep, we had one when lived up the road from you TC. Back in the early 80's.

Bit of a pain in Summer, having to have the stove fired up to get hot water.

Consequently, we bathed in the creek or under the hose alot.

Sometimes we had the stove that hot you could hear the water boiling madly.

Was good because you had to burn wood...!

 

[topcropper]

By the way, I love the look of those dutch tubs, almost worth the money I reckon.

Looks like if you pay a bit extra you can get a chimney and enclosed fire?



That's the way I'd go. Reckon it would heat more efficiently too?
They even have the hot pipe going though the flue for that last little bit extra?


See ya's.

 

[mr-ed]

Water heating Donkey

Hi Topcropper,

if you google 'water heating donkey'

you will find a large number of pictures and diagrams of wood fuelled, water heaters.