Low-tech solar hot water

[scgargoyle]

Anybody got a simple home made solar hot water unit? I'm going to play around with it a bit, since sunshine is something we have a lot of here in FL. I saw a collector somewhere that was simply copper tubing zig-zagged and stapled to a sheet of plywood. The whole thing was then plastered w/mortar, and painted black. It had sides and glazing on top. I'll have to figure out a small circulating pump, maybe even run it off solar cells. A thermostat would cut the pump off when the water coming out of the collector gets too cold. I'll either use a large hot water heater, or construct a heavily insulated tank to store the hot water. Here in FL, I can run it direct, since we very rarely get below freezing, but when I move to SC, I'll have to run anti-freeze in a closed loop. Once in SC, I'll have to store a lot more water, since I want to use it for supplemental heat. I figured I could mount a car radiator in the A/C blower, and run the hot water through it for heat. I'd have some kind of back-up heat in case the reserve tank got too cold. I also might build one for the barn, and run tubing through the slab to warm the workshop. Sound like a plan? I could use some details about a system like this, if you have any experience. In SC, I'll put the storage tank in the basement, but I have no idea how big it should be. I also don't know how many collectors I would need. I'll build a single 4X8 one here in FL for hot water.

[Fla._Deadheader]

 IN Fl. Swimming pools are heated with Propane as back-up, and the black multitube stuff you see running across South facing roofs.

  I built and sold Solar Bread Boxes in Arkansas. Used a Teel Brand Hot Water Pump, and bought the temp control unit all from Grainger. Nowadays, Internet could find good deals on this stuff. Check Ebay.

  Bread Box is as simple as you can get. Find a used GAS type water Heater. It will have the tube running through the center. It will also have a leak. 99% of the time, the leak is from the slag that popped off, after welding the tank, and is a VERY easy fix. A NEW Water Heater would be a better investment. Get a GAS unit, and you already HAVE the dual heat source unit. Just plumb in the solar before the Propane heated water Lines. 2" X 4" framed box, with Plywood back, and Poly isocyanurate (yellow w/ aluminum facing) ½" board insulation is best. Find a used Sliding Glass Door (tempered) and hinge that to a lid that has foam tape seal running completely around the top of the frame.  Install the pump OUTSIDE the box, and put the sensor to the water output.  In SC, make Methane and supply the heater with THAT.

  You can also make a Copper manifold using USED tubing and buy fittings. SOFT Copper is good, but, hard to find used, and now, expensive as New. Many options.  ;D

[Ron Wenrich]

I built a very low tech solar heater for my hot tub.  I bought a 100' roll of 1/2" black tubing at one of the box stores.  For the frame, I just used some old 1x6s that I had laying around.  I used old storm windows for top.  I use a pump to run the water from the hot tub to the heater. 

It works pretty good from April to November.  I rarely need to run the tub to get the water temperature up unless we hit a cloudy spell.  But, I'm only heating 200 gallons to 98° and not taking any water out.  Collector temperatures can get up to about 130-140° on most days.  When you pump water through, that drops the temperature.

The other year I was trying for some better efficiencies, so I went over to copper tubing to see if there was any difference.  The black tubing worked just as well.  There is less maintenance with the black tubing.  I had problems with freezing temperatures and the copper tubing.  Apparently it doesn't drain entirely, even when I manually drain the system.  So, I went back to the tubing and have no problems.

Another low tech way is to take that black tubing and put it under black plastic.  You can use that for a pool heater.

[scgargoyle]

I've seen a collector made out of black flexible pipe. It was laid in a flat coil, and mounted to a platform that could rotate. When winter comes, you disconnect the fittings, and simply spin the thing to work the water out of it. It'll be interesting to see what temperatures a collector can hit. I figured I'd rig up a 5 gallon bucket with a valve, and find the optimum water flow. Once I know the best gallons/minute, I'll know how to size my circulating pump. Another, less useful collector I saw was a clear box, filled with aluminum shavings from a machine shop, painted flat black. It was amazing how much hot air that put out. That wouldn't make a bad heater to take the chill off a barn, but it only works when the sun is out. Come to think about it, couldn't we just put all the polly-tishuns in a box for hot air....?
Deadheader- I'm not sure why I'd want a gas hot water heater over electric? I already have an electric unit.

[Fla._Deadheader]

In your original post, you talked about using Solar Panels. I figured that when you go to SC, you could make methane gas. It's real easy, and use the gas to heat the water, using a GAS Water Heater. ???

  Maybe I read more into the post than what you had written  : :

  A homemade wood Furnace would heat a house real well, using that same GAS water Heater design. Like this  : :

 

[StorminN]

scgargoyle,

In Florida, you could build a simple batch solar hot water heater... simply a black tank in an insulated box, with glass on one side. Homepower Magazine has had a few good articles about building these, here's a link to an article from a few years ago, the guy was actually in Florida...

Florida Batch Water Heater

-Norm.

[TexasTimbers]

scargoyle,

I missed your post here whenever I posted my ISPWH one. You might check out this site if you haven't already. I am convinced the ipswh is my best solar option for my  location.