Solar Thermal Water Heater For Less Than Five Dollars

This is for my Team NRG kids.  GET BUSY!!!!!!


The Team NRG is going to try and build this for a project at the Middle school. 

Thanks for the Instructable.

To heat water on a larger scale, get a tank from an electric water heater and put it in a defunct refrigerator. Lay the fridge on its back on the south side of your house and hook up the pipes. Open the door in the morning and close it in the evening. Oh, and paint the tank black!

This is a great idea, I'll try it.

Nice project, thinking about making one of these to heat a spa pool, using a solar powered pump to move the water through it.

Hi all

sorry for my limited knowledge. I guess the core of this project is that when water travels from this black coil it gets heat up right ? and the glass and foil helps to trap the heat inside the box. Please correct me if I am missing something.

Owww..., I Like it...
useful and friendly... Thanks all

you can check out the solar water heating guide here http://www.solarhotusa.com/support/literature.html to see how to make this a little more efficient. I don't think boiling the water is practical since the extra BTUs required to phase change the water.

on this form you can also find a lots informaton about project like yours http://en.electroda.com/topic338507.html (site can be translated to different languages). all temp. on this form is in C not F.

you don't want reflection, you want absorption. get a sheet of aluminum and paint it black and clamp your pipe to it. if you can't find or afford a sheet, you can use a few layers of aluminum black screen, its cheap.

I think the concept is t reflect the sunlight back onto the PIPES.

wow this is easy green and efficient

Great idea!

Great instructable!
If anyone has seen the wood fired jacuzzi systems- theres the concept of pumping cold water through heated copper pipes and back to the pool, at a nice warm temp. So rather then having this solar rig linked directly to the pool, (thus frying the people in it), I'm going to take the coiled pipes out of my wood fired system and submerge them in the boiling water collected from this one!

I love this idea for a homemade solar heater. My question is related to convection in water, it's been mentioned but I don't believe confirmed in the comments. If I were to attach a solar water heater such as this to an above ground pool in the fashion shown in my excellent diagram (art is not something I excell at!) would convection naturally force the water to flow through the piping as it heated up?

If convection would do it then I could heat my small pool up (extremely slowly!) with no pumping required at all! Otherwise i'm thinking off some sort of excerice bike water pump contraption :D

this is a very cool design but i too feel su thing is missing because we dont know how to attach the collecter to the water tank or the water inlet or for storage. it would b appreciated if that too was provided

Solar dude & Amendra

you need a reservoir for a system like this. The res is not pressure sealed. Float valve takes care of this. Injecting the hot water to your system is where the fun happens. You may need an entirely separate gravity driven plumbing set to get it to you point of use (think of the hot water side of the mixer valve in your shower or kitchen sink, or you may take a trick from "point of use tankless water heater systems, that is you return the hot water to the cold line and run the desired temp from that line rather than mixing H&C at the faucet for desired temp, but in that case you will need to pressue seal the Hot storage reservoir..... we don't need to do that in my country as most houses here have a separate waterstore to compensate for low or no water from our utility supplier, as well as functioning as an emergency reserve for natural disaters, ie hurricanes, earthquakes etc. you simply retern the output from the solar heater to the waterstore. Problem with this though is that the col;d water now comes from the fridge...
strength & peace..

How or where can you get the freon or other coolant removed from the back? Is it costly to get this removed?

Get the evaporator coil from a scrapyard; the will already have scavenged or depotentiated the gases from the evaporator coil. It's because of this that the author of this article found himself sucking dirty water, it was used to displace the refrigerant gases. In the very near future I'll be doing a thermodynamic analysis of the flow throughs for something like this. I did a basic, with some really guessed assumptions, which are , that the contained volume of the coil would be 250 ml, that the collector was 1m2, and the thermal mass was perfectly efficient at transferring heat to the evap. coil, and the recoverable energy for the collector was 85% and that insolation was worth 1kW/m2. Start temp was 25 deg C target temp was 70 deg C. Total energy required to achieve deltaC was 3560 J. 1 watt = 1 J/s. therefore at 850 watts recoverable it would take about 4_1/2 seconds to achieve delta C. at that rate the unit could energise (3600/4.5)*0.25 litres, id est 200 liters of water at peak insolation. I need to find the thermally driven flow factor for the circuit though, as i am trying to avoid using a pump. If anybody wants to collaborate though, The project is to use this heat engine to drive a Carbon Dioxide working fluid refirgerator system for community based refrigeration and solar driven climate control. I have an advantage over most of you guys however, I live in the Caribbean and I'm 10 deg North of the equator.... so my problem ain't energy input , its heat rejection.... any how... My sincere thanks to the author of this Instructable. If I do this right a lot of poor people in the caribbean are going to benefit from your hardware hacking skills...
strength & peace all...

You just let it vent into the air.

Venting Freon into the atmosphere is illegal and Irresponsible!!

Reputable Junk dealers will have freon free units and the earth will thank you!!

Cheers

which is kind of ironic..

"By using the sun instead of fossil fuels to heat your water you will be preventing dangerous greenhouse gasses from being released into the atmosphere, helping to prevent global warming."

or not.

When I was a Boy Scout, my scout master took a metal trash can and welded both ends of a metal pipe (in the shape of a figure 8) to the trash can. He set the figure 8 into the fire pit and we built the fire on top of it (read solar panel). Then he filled the trash can with the water. The pipes were connected to the trash can with one pipe above the other pipe. The lower pipe drawing water from the bottom of the can, the upper pipe putting the water back in the top of the can, (upper pipe still entering below the top of the water). We didn't have to pump or suck anything. I am not much of a scientist yet, but as hot air rises I am going to conclude that hot water rises (when interacting with cold water), because that water was scalding hot for the whole week we were camping. Also there was a spout near the bottom of the trash can as well. Hot chocolate all week!

I can't wait to try this with the solar panel.

To avoid having to go outside all the time, you would just have to bring the two pipes inside to the tank. The shorter the distance the better. As long as the coil solar panel is lower than the tank you should not have to have any pumps or do any sucking.

Troop 40 Troopmaster Mr. Durland made this for scout camping trips. I would like to build a similiar water heater trash can for my above ground pool. But don't want to build a fire every time I want to heat my pool. I like the idea of the solar panel and want to mount this to my pole barn to empty hot water into my pool. Let me know how it goes for you.

I was just thinking about other heat exchangers that might be more easily/safely available - how about using one (or more) car radiators? Or even a house radiator. Neither of them have issues with freon.

Normally you would use it with a closed loop, with antifreeze inside, you would not actually have your drinking water going through it. there would be a loop inside your water tank, and when the water in the solar heater is warmer than the water in the tank it would start pumping.

i always thought they should do this with the waste heat from air conditioners as well.

since when do you drink hot water?

I may not drink hot water…a good amount of absorption happens through your skin.... so be kind to yourself…be wise....y'all take care.

i always thought they should do this with the waste heat from air conditioners as well.

They do ;) But the more efficient your a/c is, the less effective it becomes :/ My power company recently got ri of the rebates for waste heat recovery :/

Not really sure how you would connect that to the water lines in a house. You need it to be pressure sealed to handle city water pressure. There's a basic schematic of a profesionally installed solar water heater here: drainback solar water heater

Does "drill" mean a drill machine? And what if I don't have the screw bits? I don't think we get it where I live.

Can the rubber mats used in cars be used for the backing material?

What is "A box of wood screws" ?

It would be a "box" containing screws that are used for penetrating wood.

It you don't have a screw bit for your drill machine you can use a hand tool called a screw driver. A screwdriver is a tool used to insert the screws into "wood" in this case. Most countries throughout the world have this tool and is a must have for anyone attempting this or many other projects.

This is a really cool concept, but I feel like we're missing the next step, which would be incorporating this into your current hot water system. Does anyone have suggestions on actually using this in your home, other than going out and collecting water daily from this closed loop system?

An easy application would be to route the hot water from this system to the cold water coming into the heater (or on the far side of it, close to the faucet). The heater itself is insulated, so you would have to heat the pipes themselves. This would reduce the amount of energy spent to heat up the water in the system. Like, extend it to the house, and maybe route it through copper tubing coiled around the hot water pipes. Maybe with a small (solar powered!) pump in the circuit.

yay thanks so much for posting this i need to do something like this for my science fair project

if you dont mind though may i use your idea?

I think this is a good set up accept the black background is prefered for me.

I am thinking that a small box like this (useing a bar fridge rad.) made of more non-flammable material, and placed in a focal point of a parabolic dish (say 6' diameter could get things really rockin'.

Thanks.

maybe instead of using a mat,we can use a junk galvanized sheet paint with black and use the mylar or aluminum foil as reflector...just like the solar oven...

I saw something neat the other day on YouTube. They were using steel wool in water to show how fast they could get the water to boil with a parabolic mirror. Under 3 minutes. It has to be in a vacuum or a liquid or it will burn the wool though.

Greenscience.com - a couple actors who put together a lot of videos. I believe they sell plans and parts too. Pretty good ideas and a lot of 'green science' know-how.

I think that aluminium paper reflects the solar energy outside faster than a simple inside painted in black.

i agree, maybe it is best to use the aluminum foil as a reflector of the sun from outside the frame,just like doing on the solar oven

Yeah, if you paint the back black instead, that thing will get extremely hot (I live in Israel, and most of the houses use solar water heat, they are all built with black backings)

Sucking on the hose for the water everytime it is needed to be heated is difficult. Is there no way to get this done with some device that is cheap? Say some kind of hand pump or something?

you can use a pump from aquarium,it doesn't need priming.

what if you run the hot water to a discarded water heater to store the heated water in? i'm not sure how to keep it in the loop til you need it. some one out there will have to fill in that one. by the way you just need a friend who does remodels or scavenge. i have 9 old sliding glass doors that i got paid to take out and haul off. i was planning on a green house but i like this idea better. i think the refridgerant coils would be better for radiant heating rather than putting the wate ron you or in you.

You can use a fluidyne engine to creat the pumping cycle. This lquid engin turns heat differences in to pumping power.
So when the heatr will be wormr the the out side the engine will circulate the water throw the systam (this my couse some heat lose in the system but im not sure how much).

isnt there usually freon in that tube? and when you release that doesnt it put a hole straight through the ozone lair? and isnt it poisonous?

TOTALLY HOT IDEA!
thanks for the great idea!

correct me if i'm wrong--it looks like the coils are sandwiched between the rubber mat and aluminum foil, with the V-shape frame behind the rubber mat and the rectangular-frame over the aluminum foil side, so the layer would be:

V-frame
rubber mat
coil
foil
rectangular-frame

Be VERY careful not to use PVC where it will heat up-- heated PVC will release dioxin, probably the most carcinogenic compound known. (Another reason not to install vinyl windows in your house).

"Real" solar panels use copper tubing with "fins" on them to create more surface area to absorb the sunlight & therefore heat. Total tubing capacity in a 4' x 8' panel is only about a gallon, so really it's the storage of the heated water that becomes critical. In a pumped, closed-loop recirculating system, the heated water transfers its heat to a tank of water, which heats up gradually as the system continues to pump the water through. Usually after a short period of time, the water in the tank is about125 F, suitable for showering, etc. For swimming pools, you won't need to get the water that hot (unless you have a spa).

Whatever you do, make sure the components will not release toxins. I've seen people trying to use black rubber or vinyl garden hoses, and the results have been really stinky, nasty spa water that had to be drained out.

is there such thing as stainless stell tubing?
i heard copper also has some toxicity when used as piping.
guess we cant get away from it all.

thanks for pointing out the nasties of pvc.