solar water heater supply line routing

[Fran365]

The pic is 2 ex-propane tanks I am using for the water reservoir in a solar hot water system. If the pic can be enlarged you'll see left tank has one 3/4" port and the right tank has 2. The cold water supply comes into the left tank, that line has a T where when L/tank is full it goes on to fill the r/tank.The right port on the R/tank is the hot water out.. Now when hot water is used (outside summer shower) the line pressure (25-40 pounds) will bring water into L/tank . I see an issue in pulling cold water into the hot area, which could be remedied if the cold supply coming into R/tank (or L/tank?)would deposit at the bottom of the tank. How can this be done? Hope this is clear, Fran

[Fran365]

Unless the Moderator advises otherwise I intend to document this passive solar water heater experiment. Fran

[Fran365]

These 2 tanks where filled with water to remove any propane, the handles where ground off, the surface was power wire brushed, and spray painted flat black. Note on tanks:some report an strong propane odor when working with these tanks, I did not notice that in these. I got them from a local Propane gas company that strips the valves from these old tanks and recycles the metals, they might have a quick way of deodorizing them. The issue of having supply water enter the tank at the bottom was addressed by soldering a length of 1/2" copper pipe to the bottom of the 3/4" male adapter. The sloppy fit was corrected by making a ring of 14 gauge electrical copper, tapping it into the gap between the pipe and the fitting, fluxing and soldering.

[Fran365]

The project is moving along, some of the adventure is limiting myself to in stock materials. The copper and fittings would have been DSCN4519.JPG way over $100, but where old stock from years ago.

[Fran365]

Sping/summer is a very busy time around here, but actual testing has started. Having trouble posting pics, there are some design issues with this system: I have seen 140F after 3 hours in the sun. The supply tank, on right, does not make up tank on left, incoming water simply flows over it to the left tank. Fran

[Fran365]

System with glazing off. I'll need flexible in and out water lines to allow orientation to the sun. The potential for off smells and debris in these old propane tanks has not surfaced. Exit water is clear with no smell. Fran DSCN4543.JPG
DSCN4544.JPG

[Fran365]

Final evaluation: This system provides plenty of hot water for showers, dishes Etc. The sun must be out and the glazing properly directed toward the sun for good results. The family is very happy with it and outside showers are our favorite. I have not yet had the water tested for possible problems, but the clarity and smell are fine. Fran

[bcroe]

It looks good; how long for the water to get up to temp? Up here we don't get strong sun on a very regular basis. Bruce Roe

[Fran365]

Hi bcroe: A coupe of hours work well for showers. If you are interested in something like this review my comments, A summary of improvements would include: if you layed a carpenters square on the front glazing it should point toward the sun, this type of little box heater should have flexible in/out lines that allow positioning of box toward the sun, the heater is on a table and should rotate easily, if supply water is cold well water an other larger reserve tank would help, and if using non/potable water tanks (like propane tanks) you should have the water tested after 4 or 5 rinsings. Fran