Solar Thermal Water Heater For Less Than Five Dollars

This project has been removed, if you wish to see it, or any of my other projects it is still available at my homepage www.thesietch.org 
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Kiteman3 years ago


What is the logic in removing the project from a site with several million new viewers every month, and putting it on a site with only 16 members?

Wouldn't you have more global influence if you got those 16 people to join here and form a group which others could join?
LastKnight4 years ago
I would reccomend NOT drinking the water, or even priming the coil with your mouth. Many refrigerants and the oils used in cooling systems are highly toxic and very hazardous. The least toxic commonly used is ammonia. There is no failproof way of being sure these chemicals are totally removed from the coils.
I would suggest buying new copper pipe and bending it into a coil.
1) would you suggest solid silver pipe? or solid gold even. it might be much better! some people can't afford all that but those that can, new copper pipe would be best suggestion. it'll pay for itself in time.

2)a) if a clear piping is attached to the end of the piping being sucked on then one could see when the dirty water has been sucked through far enough. could stop then.
2)b) would it be wise to pump fresh air through first to clean the air going to be sucked to encourage the atmospheric air pressurized water to climb through the coils?

3) it is unfortunate this instructible got removed. it would be nice if comments which had significant value could be entered into a concise log of the instructor's pick. then those who don't read all or any of the comments wouldn't miss out. why should everyone have to read everything? idea is to make something not talk about it.
If the refrigerant was 12 , 501 or 22 I wouldn't worry about it they are nonpoisonus, have no odor or taste. The oil would be the worse thing but if you ran a lot of soapy warm water through it you would be ok. I used to breath bit all the time and had no ill affect.
Zelgreb4 years ago
I think it depends on some of the particulars of a given background surface. A silvered surface (alum. foil, a space blanket, etc.) will reflect the majority of the sun's energy away from itself and (partially) into your coils. This property can be exploited for higher efficiency with parabolic reflectors (e.g. professional grade set-ups or solar ovens) but are more time consuming to set up than a flat reflector as we have here.

A black surface will absorb nearly all energy for some time, until it is quite energised and begins behaving very much the same way as a silvered surface. The main con of a black background is that, having absorbed a good deal of heat energy, it can stay warm for a while even if the sun is obscured. We've all seen this on parking lots before and it's a reason why the insides of many grills are black.

So, there are pro's to both, but given that there's another reflector on top (the glass) we're basically building a green house and I'd stick with silver.
solar mania4 years ago
i think you can use a pump from tank, it doesn't need priming for solar heater.
Hammerham4 years ago
Yes but using a used Refrigerator coil would that really be safe?
Wasn't freon flowing through the coils?
web224 years ago
This is a great idea. I live in an area where this would be ideal in the event of civil strife or interruption of electricity. It's simple appears to be portable and can be put together with minimal work. Good job... we might need this one soon...  relativity theory  e=mc2
RoboticKop4 years ago
better if you use mylar. aluminum foil doesn't reflect so much as it absorbs the heat and traps light. Mylar better reflector of light
ewornor4 years ago
I'm not sure about this particular system but I do have infloor heating in my house and a pump is absolutely necessary.

If my rig (which was installed when the house was built) is an example, I have a Grundfoss type UP 15-42 SP circulation pump that pulls water from two gas fired hot water tanks (our normal household supply) at 116 degrees (F). The system is controlled by a thermostat.

While I also have a natural gas furnace ( I live in central Alberta, Canada), the furnace seldom comes on unless the outside temperature dips below -25 to -30C. So, the key to only using the basement in-floor hot water system is a continuous, recirculating supply of hot water.

jacobarnott4 years ago
Also do you have an estimate of how many of each thing you used? Doing this for a school project and he needs a rough estimate of how many materials we need.
JacDubois5 years ago
Not a good idea and here's why. Glass is more stable than acrylic, but much more important is the way it passes radiation. Solar energy is short-wave radiation from a very hot sun. When it passes through the glass/plastic glazing and strikes the black fridge radiator, it is converted from electromagnetic energy into heat energy. Now, the hot radiator will begin radiating this energy back out into space, but in the much longer, infrared wavelength. Glass does not allow infrared waves to pass through, but plastics do. Therefore, glass does much more to keep the heat on the inside of the collector, where you want it.
You took the words right out of my mouth...
Glass does let IR pass that is the reason why you feel the warmth of the sun behind a window, Glass does not let UV pass, acrylic does, I have glasses that color from the UV in the sun light, when I'm driving the glasses turn colorless for the lac of UV because it can not pass glass
In colder climates, you might want double or triple layers of glass to reduce conductive heat loss.  You only need one layer of glass to reflect the infrared light back inside.  The remaining (outer) layers may be cheap plastic if you are willing to replace the film/sheet as needed.  (Of course, the insulation is actually provided by the air gap between the glazing/panes.)

The inefficiency due to thermal emission depends on the surface temperature of the solar collector.  If you are pumping the fluid rapidly, the collector does not get as warm, so it emits less infrared.  This implies that solar collectors used for swimming pools or room-air-heating are good candidates for plastic film or sheets.  

Hot water collectors emit more infrared though plastic, but they also absorb infrared from the sun that would otherwise be rejected by glass.  So the advantage of glass is more a gradual continuum than a sharp edge.  

If you look at the edge of a sheet of glass you may notice that it is a shade of green.  That is the iron content.  Special  "invisible" glass is made without iron content, is much more transparent and will pass infrared well.
mmbosworth5 years ago
Hey, can you drink this water? I've just finished making a similar on to this with a freon-removed fridge condenser, and it heats water like a charm (really impressive!), but at first the water came out oily. Now it's coming out cleaner but a bit brownish, like maybe the pipes are corroding. I'd like to use this to make coffee but I don't want to kill anyone. Anyone have ideas on cleaning/testing for chemical content? Thanks!
I'm guessing that no you shouldn't use it. Since the heat exchanger was never created with the intention of being used for consumable products, it's probably not made with food grade materials. I.e. it may have lead based solder or other nasties in it. So i don't think the only problem is cleaning the freon/oily residue/corrosion out of it. as far as testing, many big box home improvements places have home water test kits that you can send in for analysis as do some cities/counties.
justmefjs25 years ago
If you plan on using this for production you may want to consider putting the built unit, filled with air, and sealed air tight, into a plastic container with a second glass lid that you then seal air tight and pump the air out of. That will allow you to accumulate more heat in the air of the main frame and loose less due to radiation by using the vacume in the plastic container to insulate the heater from the environment. Use every scrap of heat you can! :)
macrumpton6 years ago
Wonderfully simple and effective project! I wonder if adding another coil in the box (slightly offsetting it) and making the water flow through both coils would increase the efficiency. The problem I see with your current arrangement is that the tubing and connecting wires let a lot of the sunlight go through without adding to the heating. Even with the foil bouncing the light back, I think you may be losing 25-35% of the potential heating. Another approach would be to paint the foil black and bring it in close contact with the tubes/wires so the heat it absorbs is transmitted to the water. You would need to insulate underneath the foil to prevent heat loss out the back using fiberglass insulation or foam or even scrunched up paper.
I totally agree with your second approach.  Put the foil against the wires, bond them with the black solar paint.  The heated foil, although thin, will directly conduct solar heat to the wires which in turn conducts heat to the serpentine pipe.  By using the thickest Heavy Duty foil available, you get the best conduction.  This should Reduce the air temperature close to the exit temperature of the water, in turn reducing thermal losses through the glass.  

I am sure that the best use of a second coil (refrigerator back) is to build another solar panel.  

I also agree that insulation is very important; I would put it on all sides, emphasizing the back.  I love the idea of cheap crumpled paper, but the chance of a high stagnation temperature makes combustible insulation a hazard.  The paper should be treated with a borax solution to provide flame suppression.  This is cheap insurance.  The inside surface of the insulation should be an excellent IR reflector, such as white paint.  This will return some of the IR emissions to the black painted foil, wire and tubing.

avid0g avid0g5 years ago
 Or is it 7 oz Borax and 3 oz Boric acid in 2 quarts water solution?
cararta5 years ago
re google translate,
on page 1 of the  text click select all  then
then paste this into the goole box and it will translate about 20 pages, guess you could go to pg 21 and repeat

bnmelech5 years ago
Here in lower deepweeds of northeastern Arizona, at about 6,000 ft. MSL, we use old electric hot water heater tanks with the jacket stripped off, leaks fixed, and painted black. We then put them in a box behind glass (double pane) and point them south-ish. Usually a minimum of two tanks work best. As we are well beyond any electric power, and propane costing $3.00/gallon, every little bit helps. We still have our propane water heater, but this system preheats the wet stuff even in the winter. Uh, almost forgot, the better the insulation in the box, the better the system. We've seen water temps to 160, but that's quite rare. About 140 is nominal on a sunny day.
Hebinho5 years ago
 Aside from the fact, that running water through metal tubings - especially copper - will not have any negative effect when being used for showering or washing purposes only, one of the best solutions I found, is the manual at www.sociedadedosol.org.br/arquivos/Manual%20Manufatura%20ASBC%20ingles%20out04.doc
They are using extruded PVC ducted wall-boards for collectors and common PVC piping, so the water quality practically is not changed at all.
There is another solution from an inventor, using soft drink bottles (PET) and common PVC piping, which can be found at
This one is NOT in English, but gives a good overview of how the system is working and how cold AND hot water are "layered" in one single reservoir!

Free and easy translation at http://translate.google.com/#

Note: original is in Portuguese.
 Says it's too large to translate.
I dunno what happened. I worked when I did it on 22 April but you're right, now it reports "too large".

If you pm me your email, I'll send you the translated copy.
jaketeater5 years ago

This is a video I made about my solar water heater.  Its more expensive than yours (about $300 total) but it heats up 80 gal (310 liters) to 135 F (55C). 

Thats sweet! Looks nice around there, you have cows. Oh and a lot of foam. That stuff is like ductape, it can be use for anything.
Yeah - gotta love the foam.  Here its used to put doors in place.  Just hold the door frame in the hole in the wall, put spray foam around it and your done!  Holds well and makes a good seal too.
Impressive work brother.  I'm a former CA Police Officer, now a Dept of State consultant and I've seen a lot of great ideas coming from my fellow americans abroad.  I think we North Americans are very resourceful and have common sense.  Not saying all humans are not intelligent but we seem to do it faster thereby getting it done instead of sitting around thinking about it.  Good job brother.

Hey I'm thinking about going to Brazil.  Would you have more info on the Missionary work you are doing there?  I may be interested in taking a break from what I do for a few months and helping out.

You can check out more about the orphanage by going to http://www.clmhome.com or go to my website http://www.teaters.com

I will send you an email so that you have my contact info. 

static5 years ago
I had always planned on using the Auto AC condensers I have around here the same way after painting them flat black. That or spend the money on a coil of black poly tubing
butchie505 years ago
 Someone asked about using car radiators instead of the refrigerator pipes.  They may not have issues with freon, but they do have issues with antifreeze, which will kill you if you drink it.  I prefer to live.
 You can always wash out the antifreeze (refrigerant), but the real killer is the metals (lead, etc.) that leach into the water.  That is why you need to use pipes and fittings that would be used in potable water systems, or a heat exchanger good for potable water.
Or a plastic car radiator as some now are.
Just the tanks are plastic, right? No doubt the metal tubes are soldered to the metal headers tha plastic tanks are clamped to.
Why does the drinking water have to run through the radiator.  Make the heating a closed loop where the collecting coil is in the sun and  another coil in a sealed vessel to transfer the heat but no chance of poisoning anyone.
MaXoR5 years ago
Just wanted to put something out there so people know....

Aluminum foil is a horrible option for reflection of sunlight, or light in general. If you're after reflection on a budget, go raid your local first aid rep, and get a "Thermal Blanket". It's made of reflective Mylar, and is VERY LIGHT, tough, and best of all reflective, however it reflects best if put as a covering over some cardboard or something flat.

I personally use it for my indoor garden, and used to use tin foil/aluminum foil. Best decision I ever made since it's noticeably better at reflecting light.

(I realize this however doesn't pertain to this ible as it's already been discussed that it's better to have a black aluminum plate to mount this too... just thought my info was note worthy)
animes255 years ago
I am agree, with everyone, you should use black background, so the water will heat even more, the black thin foil will get hotter and will irradiate more heat to the tubes.

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