Shipping Container Swimming Pool

[Scotty_014]

I'm currently investigating the viability of making a swimming pool for my home, from a shipping container. I can get this made very cheaply as i work in the industry.
Given that the pool will basically be a steel tub, i'd like to keep it heated by solar power, so as to raise the temperature of the water by approx 10 Deg C from ambient.
The whole container will be buried in the ground, so as flush with ground at the top surface.
I live in Sydney Australia, so the temperatures in winter don't get down too low, most days about 13-18 Deg C in the middle of the day.
The question i'm debating is whether to heat the water by cycling it out and through a heater then back in. Or to heat the steel tub by running an electric current through it, from solar power source??
The size of my steel tub is (L)6.9m x (W)2.2m x (Ht)2.2m, using 3mm thick mild steel.
I'd welcome all comments on whether this is possible? The power that would be required? And the appropriate solar system setup that would be required?
If it is possible to heat this way with solar, would a 24V system be suitable?

Cheers,
Scotty...

 

[nosys70]

container are made of metal. Metal is very conductive (eletricity and thermal).
to get the container not to explode when filled of water you probably will have to reinforce with concrete on the outside.
And water for swimming pool is usually pretty corrosive...
so in my opinion, it will be the hell to keep water warm in a such setup.
the best is to heat water directly with some solar heat panel or tubes.

 

[iceledoar]

It will hold the water just fine after being coated with some water proofing and buried in the ground. I assume you have a ton of sun so a solar water heater is in order. I love the idea, keep us posted.

 

[45North]

I'm currently investigating the viability of making a swimming pool for my home, from a shipping container. I can get this made very cheaply as i work in the industry.
Given that the pool will basically be a steel tub, i'd like to keep it heated by solar power, so as to raise the temperature of the water by approx 10 Deg C from ambient.
The whole container will be buried in the ground, so as flush with ground at the top surface.
I live in Sydney Australia, so the temperatures in winter don't get down too low, most days about 13-18 Deg C in the middle of the day.
The question i'm debating is whether to heat the water by cycling it out and through a heater then back in. Or to heat the steel tub by running an electric current through it, from solar power source??
The size of my steel tub is (L)6.9m x (W)2.2m x (Ht)2.2m, using 3mm thick mild steel.
I'd welcome all comments on whether this is possible? The power that would be required? And the appropriate solar system setup that would be required?
If it is possible to heat this way with solar, would a 24V system be suitable?

Cheers,
Scotty...

Don't like the idea of running current through tub. Wouldn't that electrocute your swimmers?

 

[snoobler]

Heating the steel tub by passing an electric current is a complete and total waste of time and energy. First, you only get heat from current when you have a resistance. such a massive and relatively thick chunk of steel, it should pass current very easily.

Even if you had enough resistance to produce heat, you have 33,400L of water assuming it's filled to the brim. To raise that volume by 10°C, you need 1,398,391,200 J of energy or 388.4kWh - about 4 Tesla Model S batteries. In order to gain that much energy from PV in a typical day, you'd need 77,680W of power, assuming 100% conversion Even 1/10th of that is very expensive, and you'd likely fall behind due to cooling at night.

You're also going to be fighting the 10°C temperature of the earth, so you need to thermally insulate the container from the earth.

Circulating the water through something like this is probably much more effective for solar heating:

Solar power the pump and scale this as needed. Based on the visual size of the pool in that video, it's probably about 2/3 the size of yours. It would also work as a pool cooler at night by providing more radiant surface area, though you couldn't run the pump on solar at that time.

For optimization, I'd paint the interior black and put a clear plastic cover on it for some greenhouse effect too.

 

[Scotty_014]

Hi All,
Thanks for your comments, i'll try and answer them all here.
- The container will be strengthened with extra vertical members to withstand the hydostatic water pressure.
- The container will be painted with a 3 coat marine spec painting system, similar to that used on ships.
- I will spray foam insulating material to the outside of the steel tub.
- Attached is my 1st draft design of the pool.

snoobler: Many thanks for your calcs and comments on the practicality of heating the steel tub by electricity. This is the part i had no clue about. I have seen the heating elements in water tanks and thought i could make the whole steel tub to be a similar element. Could you let me know the formula's you used to calculate the energy requirement figure.
I've also seen these circular tubing DIY heating projects. I was planning on building 2 of these and mounting on the roof of my house.

 

[snoobler]

Takes 4218J of energy to heat 1 kg of water 1°C. 1 kg of water per L. I calculated liters based on cubic meters. The number of liters * 4218J = the total energy needed to heat the volume. A Watt is 1 J/sec.

I did them kinda on the fly, so I might have made a miscalculation (just double checked... don't think I did).

Solar energy is about 1000W/m^2. You'll get a lot more of that captured as heat (50%+?) than as PV (20%). Insulation is critical. Painting the bottom of your pool a dark blue will also help a LOT (as will a solar blanket).

It's 40-42°C for us right now, and my pool is so warm, it's like I'm swimming in someone else's saliva. The above ground pool doesn't get its heat sucked away at night like an in-ground. You may find it hard to find a balance between heating and the need to cool off.

 

[Scotty_014]

Hi snoobler, many thanks for the calcs and advice. I think the combination of spray insulation, dark blue colour paint, DIY heating oils, & solar blanket is what i'll progress with. Together with a solar system to run the 24V water pump.
For occasional extra boost of heat for the spa; what do you think about those videos using solar power & battery to energise glow plugs mounted into a 44 gallon plastic drum, and cycling the water through that?

 

[Fred S]

You could construct something (an insulated barrel or tank that has water slowly circulating through it) and add standard water heater elements to heat the water. They are very cheap. In North America they are commonly 3500w or 4500w each, at 240v. Regardless of the method for heating, to snoobler's point you have to get a lot of watts (joules/sec) into the water. You can use his numbers to estimate how many watts, and how long, (in ideal conditions) it would take to heat your volume of water say 1C.

To give you a very rough idea of what to expect, years ago I rigged up two 4500w elements in a portable pipe tree, and would simply set it inside an 18,000 gal above-ground pool. The elements were grid powered, so they generated a full 9,000 watts. It raised the water temp more than 5F over the course of 8 hrs or so, which is actually a lot from a swimming comfort point of view.

 

[Scotty_014]

Many thanks Fred.
Your info gives me a good indication of what i'm up against with this DIY project.

 

[iceledoar]

Don't like the idea of running current through tub. Wouldn't that electrocute your swimmers?

Do you get shocked in the shower?

 

[Xerxes]

I vote that you bury it deeper and make it an Apocalypse Shelter. for end of times, just like the media says is happening right now!.

Buy a second one-bury it deeper than the first- to use as a cistern......and if you want use it as your own personally underground pool.

Buy a third one-bury it even deeper fill it with food for when that runs out.

Buy a fourth one-bury it the deepest-and fill it up with solar panels and ALIBABA LiFePO4 batteries so you have electricity after the pandemic passes.

 

[AussieInSeattle]

I'm currently investigating the viability of making a swimming pool for my home, from a shipping container. I can get this made very cheaply as i work in the industry.
Given that the pool will basically be a steel tub, i'd like to keep it heated by solar power, so as to raise the temperature of the water by approx 10 Deg C from ambient.
The whole container will be buried in the ground, so as flush with ground at the top surface.
I live in Sydney Australia, so the temperatures in winter don't get down too low, most days about 13-18 Deg C in the middle of the day.
The question i'm debating is whether to heat the water by cycling it out and through a heater then back in. Or to heat the steel tub by running an electric current through it, from solar power source??
The size of my steel tub is (L)6.9m x (W)2.2m x (Ht)2.2m, using 3mm thick mild steel.
I'd welcome all comments on whether this is possible? The power that would be required? And the appropriate solar system setup that would be required?
If it is possible to heat this way with solar, would a 24V system be suitable?

Cheers,
Scotty...

Not solar/heating related, but some good info here on the diy approach including what he would do differently:

theepic

Just another WordPress.com weblog

theepic.wordpress.com

And another:

DIY Pool Made from Shipping Containers | SANI-TRED®

Make a DIY pool out of shipping containers in your backyard with SANI-TRED's versatile waterproofing products! You can find more detailed information online.

sanitred.com

 

[Picasso]

Was a company that made these out of Australia think...

 

[Scotty_014]

Thanks Aussie. I've just read through the 2 links you provided. Good background info from a guy that has done it before.

 

[JoeHam]

If you end up barrel heating this may be helpful:

 

[Haugen]

You can buy a prefabricated shipping container pool. Might not be worth the effort to DIY

DIY Tin Can Swimming Pool - CCR Industrial Sales

DIY Tin Can Swimming Pool Link to item on our web store: https://ccrind.com/product/14022/ Please do not comment on posts. If you require more information, contact us directly through messenger, phone, or email. Item Condition: Used If you are interested in a DIY home project, we can help get...

ccrind.com