Inexpensive way to warm 150 gallons of water outside during the ten to five sunny hours? Featured

Check swimming pool suppliers. There are solar covers to add some heat. They float on top.

The underlying problem is the amount of energy required to heat that amount of water. To heat it by ten degrees, for example, is going to require about 6 kilowatt hours. The most you'll get from the sun in ideal conditions is about 1 kilowatt per square metre, and that only around solar midday. Then you have losses by radiation, conduction and evaporation.

So even to get this working at all, you need something with a large surface area to capture the sun, and you'll need some way to circulate the water, so that the cold water is being heated, rather than already hot water.

This is essentially what commercial solar hot water systems do.

Sylvia.

Alternative is a solar bag for a shower sold for camping.

Water bed heaters?

That might be enough, it keeps a lot of heat from escaping. Or for sure a solar heating panel like they sell for pools connected to a small pump would quickly get it to whatever temp he wants. Probably don't even need the pump, the tank has a fitting on the bottom, setting up a solar panel in a vertical convection loop would probably do it.

If a short garden hose is getting hot, then the op might be able to buy enough black rubbery garden hose to fill 150 gallons but I don't know how to make the calculation as to the length needed.

He's empty the tub every night and fill it up from the 150 gallon garden hose reservoir, where the length is the only unknown I can think of.

That way, the water would be free of contamination such as algae & bugs. But how long would 150 gallons of typical garden hose need to be?

$ printf '%f\n' $(( (150.0 * 231.0) / (3.1415926 * (5.0/8.0) * 12.0) ))

just under 1500 feet of hose with 5/8" inner diameter.

Correction, just under 3000 feet (using radius instead of diameter to calculate volume of a cylinder).

$ printf '%f\n' $(( (150.0 * 231.0) / (3.1415926 * (5.0/8.0/2.0) * 12.0) ))

That comes to about a dollar a foot using this retail pricing.

mike wrote on 19.05.2023 01:05

This 3/4-inch ID vinyl tubing is a dollar foot but maybe cheaper wholesale?

rubber? vinyl? pvc?

Those panels are designed for continuous flows and lots of pumps and pipes.

This pipe volume calculator can help the op with obtaining 150 gallons of static water that just sits in the tubing to be used as a one-shot fill.

What's the least expensive suitable tubing material? Galvanized? PVC? At what inner diameter does sun heating of static water become infeasible?

Looks like he needs 1500 feet of hose.

Calculation Results Using these mathematical conversions, you can calculate the volume of water inside a 3/4-inch hose to be 1.01 gallons. The volume inside a

Which will survive constant exposure to sunlight? PVC is a non-starter in that respect, unless protected from UV with a UV absorbing/reflecting coating.

This is a popular thread so I want to join in. Geo-thermal! Not sure if's cost-effective, but it will be hot enough and always available. You can use the left-over to heat your house.

This is pretty amazing, made of steel and all.

Not for your use, but just so people know: They promote the one above as non-kink but there are other non-kink as well. This one really doesn't seem to want to kink:

I don't know about sunlight but I had my pool hoses in the sunlight plenty of times.

I think this whole plan is suspect, but this is the hose you would want to use:

The walls are very thin, it should heat well. Much better than garden hose. Go to any pool supply store they'll have the stuff to join hoses. That's 100 ft at $45. I saw another lesser known site at $32.

I've seen panels with water channels inside meant to heat pools with sunlight. Yes, they will be expensive. They will also work.

Nice selection.

Those are all over 100 psi so what does a normal garden hose need to be safe? Probably 100 psi is about the bare minimum considering the heat.

I thought there was only rubber, pvc & vinyl but those are polyethylene. How does polyethylene hold up to the sun compared to the other materials?

Also, some of the more expensive tubes in that list are called "Advanced Drainage Systems" - what's that mean (and what does IPS mean in that page)?

What's the best size assuming it's attached to a garden hose spigot?

The 5/16 inch is 23 cents a foot (37,648 feet x $0.23/foot = $8,659). The 1/2 inch is 51 cents a foot (14,706 feet x $0.51/foot = $7,500). The 3/4 inch is 36 cents a foot (6,536 feet x $0.36/foot = $2,353). The 1 inch is 57 cents a foot (3,676 feet x $0.57/foot = $2,095). The 1-1/4 inch is 83 cents a foot (2,353 feet x $0.83/foot = $1,953). The 2 inch is $2.07 a foot (919 feet x $2.07/foot = $1,902).

The volume length calculations came from here.