# The Solar Heated Stock Tank Prototype



## SolarGary

Hi,

It took a while longer than expected, but here a first cut at a solar heated and insulated stock tank:
http://www.builditsolar.com/Experimental/StockTank/SolarStockTankProto.htm

Any thoughts or ideas for improvements appreciated.

Gary


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## Liese

Gary, is there a benefit to have that much water in the tank, does that capacity relate to how long folks generally want to go between adding water? Also if you went to a round shape wouldn't you reduce the surface area in relation to the water volume? I have sheep & goats, not horses or cattle but in the winter we find that at night they don't seem to drink much, if any, water based on the levels from the previous evening. So would it be do-able to have an insulated cover that is put on at night?


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## fishhead

Thank you!

Could you have gained by insulating the south wall and making an air space around the tank and then put self closing air vents on the top and bottom of the south wall to allow air from the collector to circulate between the wall and the tank during the daylight hours?

Some days my goat waterer is completely dry twice a day. There's no way they are drinking it based on how little they drink in the summer. I'm wondering if maybe our cold dry air speeds up evaporation.


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## SolarGary

Liese said:


> Gary, is there a benefit to have that much water in the tank, does that capacity relate to how long folks generally want to go between adding water? Also if you went to a round shape wouldn't you reduce the surface area in relation to the water volume? I have sheep & goats, not horses or cattle but in the winter we find that at night they don't seem to drink much, if any, water based on the levels from the previous evening. So would it be do-able to have an insulated cover that is put on at night?


Hi 
I choose that size because its about the size of the small tank that my neighbor uses for his horses (4 or them) -- his big tank is about twice as large. I gather this just so they don't have to be filling them a lot.

I think it gets harder to make the insulation and solar heating work as the tank size goes down, because with small tank you end up with a larger ratio of surface are to volume, but I think that it would still probably work unless you are in a really extreme climate.

Gary


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## Blu3duk

back in the day when i was akid and we had water troughs exposed, I took a can of black spray paint and painted half the tank which faced south, the heat absorbed enough that it c=kept the water ffrom freezing more than the cattle could break them selves mostly no more than a 1/8 inch think. whereas befoer i painted them the ice on the walls would get several inches thik and i would end up chopping it out, and yes i did poke one hole in a tank, but then so to my dad who gave me the axe to use..... a drill and extensions cord [this was pre-battery operated tools] flat bar and a chunk of inner tube for gasket fixed the holes.

We had enough animals that we required two troughs for the most part though they were the small oval and not the bigger round tanks.

If we had it to all again I think the self watering units that have the frost free shut offs and drain below ground would be what we put in, even if it required a dry well and gravel to be sunk in, the head ahce saved would be worth it, though at that time of the year i did not have as much to do anway.... now the time would be spent or mis-spent online......

but the design looks good cause it really does not take much to keep the ice thin just encasing the trough would help, our problem with having added an encasement, would have been we would have needed another trough or three for the number of animals at one time to drink without fighting for water... cause it seems when they got thirsty it was all at once and not one at a time..... cattel are notional, kind of like a few women ive been around..... [hope my wife dont get wind f that statement]

William
ohadI <------maybe she wont know it was me eh?


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## SolarGary

fishhead said:


> Thank you!
> 
> Could you have gained by insulating the south wall and making an air space around the tank and then put self closing air vents on the top and bottom of the south wall to allow air from the collector to circulate between the wall and the tank during the daylight hours?
> 
> Some days my goat waterer is completely dry twice a day. There's no way they are drinking it based on how little they drink in the summer. I'm wondering if maybe our cold dry air speeds up evaporation.


Hi,
Yes, I think you could have an absorber with space between it an the south tank wall, and use those light poly flapper valves to prevent cooling backflow at night. I left enough room behind the glazing to try that, but thought it would be nice to see what the simplest approach does first. But, adding a separate absorber sheet would not add much to the cost or build.

I think it would also be interesting to see how it does with the south wall just insulated with no solar gain. It may be that with water being added regularly, that nothing more is needed than good insulation?

Still waiting for some really sun and cold weather.

Gary


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## deaconjim

Keep an insulated tank of water next to your stock tank connected with a float valve that will refill the tank as the animals drink. The tank can be painted black to absorb heat just like the stock tank, and the warmer water will help keep the temp up in the stock tank. (Be sure to insulate the connecting line to keep it from freezing.)


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## mplatt4

you can also use geothermal power by digging a hole down below the frost line and putting in a big tube either metal or the carboard type they sell as concrete forms or big plastic pipe try to use at least 12 inch pipe and set the metal tank on top of the pipe the ground temp at the bottom of your hole should be 50 degrees all year around and as heat rises it will rise and keep the water from freezing try to get a tight fit from tube to tank and may need 2 or 3 tubes for big tanks in south dakota we went 8 feet deep but would be less the further south you got


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## rambler

I've mentioned before, the earth tube like mplatt4 describes works great (I got the http://www.cobett.com/ which they explain well on their web site) and it uses zero electricity. It was frozen over this morning, but we had minus 15 degrees with a 40 mph wind last nite, and windchill _does_ affect open water. As they say on the web site, simple to chip loose the inch of ice and it won't freeze itself full, the ice insulates it from doing any more than that. And you need to check water levels once a day anyhow.

Really like it.

Another way is to get a lot of water, several 100 gallons, inside an old mining tire on it's side. Concrete the bottom, put a cover over most of it. The water comes up in the center, surrounded by all the gallons of water so it doesn't freeze. The sun heats the cover & tire, the cattle drink enough water to keep it curculation, & the huge volume of water takes a long time to cool down so it surrvives the cold snap now & then. This does require a fair amount of livestock to turn the water over tho.

The solar is interesting, but you'd need to keep the critters away from the glazed side which must face south so you really hamper it's location, you need to supply a water line which is prone to freezing up, and here in MN we get 4-5 day periods of no sun with a very shallow sun angle even if it is shining an hour or 2. So, when needed most, you get almost zero help.

Nice project tho, I like the way you are going about it & the data. Keep us informed!

--->Paul


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## sammyd

Looks like a good idea.
More portable than a hole in the ground or an old mining tire full of water and concrete.
Since I move my winter lot around from year to year to fertilize the garden areas it seems like it would work for me.
If you try the seperate absorber sheet let us know the results please.


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## Micahn

How about a battery powered stock tank heater with a small solar panel to keep the battery charged up ?
Here is a example what I am talking about, http://www.hydrogenappliances.com/stocktankheater.html

Put a setup like that in your insulated tank and I would say it would work great.

I would say you could get it going for under $100 and would last for many years.


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## SolarGary

mplatt4 said:


> you can also use geothermal power by digging a hole down below the frost line and putting in a big tube either metal or the carboard type they sell as concrete forms or big plastic pipe try to use at least 12 inch pipe and set the metal tank on top of the pipe the ground temp at the bottom of your hole should be 50 degrees all year around and as heat rises it will rise and keep the water from freezing try to get a tight fit from tube to tank and may need 2 or 3 tubes for big tanks in south dakota we went 8 feet deep but would be less the further south you got


Hi,
I've seen this mentioned before -- I have to say I'm a little bit skeptical -- at least in our climate.
I have a temperature sensor buried 4 ft down, and during the winter it usually reads around 38F -- does not seem like this is going to provide much warming?
I suppose one could go deeper, but this gets to be something of a project.

Does anyone have this setup working in a cold climate?

Gary


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## wy_white_wolf

Micahn said:


> How about a battery powered stock tank heater with a small solar panel to keep the battery charged up ?
> Here is a example what I am talking about, http://www.hydrogenappliances.com/stocktankheater.html
> 
> Put a setup like that in your insulated tank and I would say it would work great.
> 
> I would say you could get it going for under $100 and would last for many years.


I'd say you figured way off.

That little heater takes 300 watts. It would take a 75 watt panel all day to produce what it uses in 1 hour. 

300 watts/12volts=25amps. Thats a pretty big draw. It would take a 600ah battery to power it for 1 day. Hope you don't have a second cloudy and cold day as batteries freeze when left uncharged in the cold. Then it's time to buy a new one. So much for lasting many years.

My guess is it would be closer to $5000 to run that little heater in your stock tank with a battery/solar setup.

If one really wanted to go this way, I feel your best option would be to run it solar direct. 300 watts of panels and no battery. Let the watter heat up during the day and carry it thruogh the night. It would still cost about $1500 to $2000.


Gary,

I like your tank. Just wondering how you are planning on keeping the critters from chewing on the plywood? I think you could take two metal tanks (one lightly smaller than the other) and place one inside the other and pray foam the gap between them on 3 sides. Seal the opening between the 2 on the top and paint the outside black. Would be alot more durable and still portable. 

Growing our stock tanks (in the field for cattle) always had earth piled up around them. Then we floated tires in them to absorb the heat and melt any ice that formed.

WWW


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## SolarGary

rambler said:


> I've mentioned before, the earth tube like mplatt4 describes works great (I got the http://www.cobett.com/ which they explain well on their web site) and it uses zero electricity. It was frozen over this morning, but we had minus 15 degrees with a 40 mph wind last nite, and windchill _does_ affect open water. As they say on the web site, simple to chip loose the inch of ice and it won't freeze itself full, the ice insulates it from doing any more than that. And you need to check water levels once a day anyhow.
> 
> Really like it.
> 
> Another way is to get a lot of water, several 100 gallons, inside an old mining tire on it's side. Concrete the bottom, put a cover over most of it. The water comes up in the center, surrounded by all the gallons of water so it doesn't freeze. The sun heats the cover & tire, the cattle drink enough water to keep it curculation, & the huge volume of water takes a long time to cool down so it surrvives the cold snap now & then. This does require a fair amount of livestock to turn the water over tho.
> 
> The solar is interesting, but you'd need to keep the critters away from the glazed side which must face south so you really hamper it's location, you need to supply a water line which is prone to freezing up, and here in MN we get 4-5 day periods of no sun with a very shallow sun angle even if it is shining an hour or 2. So, when needed most, you get almost zero help.
> 
> Nice project tho, I like the way you are going about it & the data. Keep us informed!
> 
> --->Paul


Hi,
The Cobett does seem like a good way to go, but kind of pricey and requires a water line to it?

On using solar, the low sun angle is actually good for vertical collectors, and the reflection of snow makes it even better. Around here the coldest weather (the -20F stuff) almost always comes with lots of sun. 
I think that if the insulation can be made good, and the size of the open water can be kept as small as practical, the tank may be able to carry through a number of days of cloudy and subfreezing weather. I've still got the logger on the tank, and will see how it does when we get really cold weather. In more than a week with no water changes there is still no ice, but the last couple days the high has been above freezing.

Around here, people commonly use electric stock tank heaters to keep tanks from freezing. This is expensive with metal tanks that have no insulation and lots of exposed water surface. One approach that seem sensible to me would be to use the this cheap insulated and solar assisted tank and still keep the stock tank heater that would come on in extreme conditions only?

The glazing is polycarbonate and pretty tough (its the football helmet stuff), but I've seen solar pumping/watering arrangements where they just used a small local fence to keep stock away from breakable stuff.

Gary


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## Windy in Kansas

Your system looks workable.

When I ran between 50 and 100 head of cattle I used a Johnson brand stock tank heater. I finally dug an old coal or wood fired one out of the iron pile and put it to use after some repairs. I was using two ten foot diameter sock tanks so had to pump water into them daily. That alone helped a lot.

When I would bank the fire well in the evening I would still have some open area of tank the next morning, or at least only a thin layer of ice to break for the stock.

A few years ago there were posts on these forums that told of using a road culvert buried vertically in the ground to convey warmth to a tank to keep it from freezing. The tank was simply placed over the top of the upright culvert. I seem to recall that it had to be 8 to 10 feet long for success.

There are old road culverts that are too rusted out to use again so it might be worth a try to find one to use in an experiment.


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## rambler

SolarGary said:


> Hi,
> I've seen this mentioned before -- I have to say I'm a little bit skeptical -- at least in our climate.
> I have a temperature sensor buried 4 ft down, and during the winter it usually reads around 38F -- does not seem like this is going to provide much warming?
> I suppose one could go deeper, but this gets to be something of a project.
> 
> Does anyone have this setup working in a cold climate?
> 
> Gary


I put mine in 8 feet deep. I think 6 feet would have been enough, but, why do it 1/2 way & be sorry.

Insulation is the key for our really cold climates.

I thought for a while on what system to go with, was thinking of the electric ones. But, I'm a cheapskate.

I have been very happy spending my money up front on the Cobett, and not spending a dime on electricity these following 6-7 years. I'm sure I am banking money now - if I only spend $10 a month on the well insulated but still electric units that are common around here, that would be $60 a year. The Cobett would be about free now. And those insulated but electric setups cost about as much as the Cobett did. Mine has worked with 10-30 head of cattle using it every day, have not replaced any parts at all. I think the valve seal is finally getting old, will need another stopper this spring.

As others mention, you can use any tube into the ground. However I think it is very important to insulate that tube to below your frost line - in my case 4 feet or more. Otherwise that small tube will leak a lot of heat out the sides on the way up, and you are right - might only get 38 degree air to hit the bottom of the little tank. Mine will sweat the bottom of the tank - must be delivering 48-50 degrees of the available 55 degrees from the earth.

If one wants portable, or does not have a water line, etc. - there is a lot of room for other designs such as your solar. I enjoy seeing what you are doing. Perhaps you can learn a few ideas from something like I have, perhaps not.  Setting what you have on top of an insulated hole in the ground can supply heat around the clock, cloudy weather or nightime..... More options. 

--->Paul


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## fishhead

I put out a 2 gallon bucket of slightly warm water most mornings for my birds in addition to their heated water pan and even in -10 F there is liquid water left in the bucket each evening. The bucket is frozen over but there is usually a hole in the ice. I think the ice helps insulate the water and keeps it from freezing.

We've had some great weather for testing your solar waterer. It was -20 F last weekend.


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## SolarGary

wy_white_wolf said:


> Gary,
> 
> I like your tank. Just wondering how you are planning on keeping the critters from chewing on the plywood? I think you could take two metal tanks (one lightly smaller than the other) and place one inside the other and pray foam the gap between them on 3 sides. Seal the opening between the 2 on the top and paint the outside black. Would be alot more durable and still portable.
> 
> Growing our stock tanks (in the field for cattle) always had earth piled up around them. Then we floated tires in them to absorb the heat and melt any ice that formed.
> 
> WWW


Hi WWW,
The one tank inside the other sounds like a good way to go -- durable.

It does loose the solar gain part, but if the tanks are well insulated that might be enough -- especially if new water is added each day. 
I suppose one could experiment with leaving the insulation out of the south gap between the tanks, and then paint the south side of the inside tank black and put a window in the outside tank on the south side to pick up solar heat.

So, the floated tires picked up some heat from the sun, and actually kept the water around them open? 

Gary


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## wy_white_wolf

They stayed open around the tires. It might freeze though the night but as soon as the sun came out it would melt around them faster than around the sides of the tank. These were about 12' diameter stock tanks. Grandpa always said it was for the heat from the sun and they kept the wind of the surface of the water.

After I posted I was thinking about the window in the ouside tank too.


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## SolarGary

Hi,

The tank is still chugging along with no ice -- updated performance plot here:

http://www.builditsolar.com/Experimental/StockTank/SolarStockTankProto.htm#StockTankUpdate

Gary


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## Silver Bullet

Gary,

Thank you for your leadership on the solar stock tank.

We need to keep cattle tanks free in remote fields.....no electricity. We do have underground hydrants. Our mean annual heating degree days is 5200....we get down to 20 degrees with an average 9 MPH winds for a month in the winter and only 40% sunshine. Funds are very limited.

Do you think this will work? Put a Rubbermaid 100 gallon oblong tank inside a Rubbermaid 150 gallon tank and use Great Stuff spray foam to insulate between them and press in 4" corrigated pipe to protect the insulation. Float three tires in the filled 100 gallon tank and install Plexiglas in the center of the tires to further reduce the surface area. My thoughts were that due to the low amount of sunshine we should focus on insulation versus solar gain.

Any recommendations?

Again, I appreciate your contributions.

Thanks


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## SolarGary

Silver Bullet said:


> Gary,
> 
> Thank you for your leadership on the solar stock tank.
> 
> We need to keep cattle tanks free in remote fields.....no electricity. We do have underground hydrants. Our mean annual heating degree days is 5200....we get down to 20 degrees with an average 9 MPH winds for a month in the winter and only 40% sunshine. Funds are very limited.
> 
> Do you think this will work? Put a Rubbermaid 100 gallon oblong tank inside a Rubbermaid 150 gallon tank and use Great Stuff spray foam to insulate between them and press in 4" corrigated pipe to protect the insulation. Float three tires in the filled 100 gallon tank and install Plexiglas in the center of the tires to further reduce the surface area. My thoughts were that due to the low amount of sunshine we should focus on insulation versus solar gain.
> 
> Any recommendations?
> 
> Again, I appreciate your contributions.
> 
> Thanks


Hi,
This is the latest version -- I did this for the next door neighbor just as winter was starting last year. She used it all winter and thought it was great -- we just set it up for this winter last week. 
http://www.builditsolar.com/Projects/WaterHeating/SolarHorseTank/SolarHorseTank.htm


Some others have tried similar (and not so similar designs), including a very nice one by CS from this forum. The are all listed here:
http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm#Animals

The one titled "Bob's Insulated Stock Tank" basically relies on insulation only, and used the Great Stuff for insulation. The inside is a Rubbermaid tank. You might have a look at it. I've not heard from Bob on how well it did over the winter.


I think that an approach that uses just insulation and no solar gain could work well. If you can limit the water surface area that is exposed to the weather to just enough to let the animals drink it will have a lot better chance. One person suggested using a plywood top, then cut a circular hole in the top that one of the small plastic garbage cans just fits, then cut out the bottom of the garbage can and push it into the hole so that the bottom faces down, and the lip on the top sits in the hole in the plywood. This sounded pretty good to me, but we have not tried it.

Your climate is quite a bit milder than ours, so I think you have a good chance.

Gary


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## Angie DDD

I just use a standard in tank heater that one of my husband's friends who is an Indianapolis electrician rigged up to a solar panel for us. The solar panel goes on top of the fence post so it gets good light all day and just powers the water heater. Our horses never really drink at night. It's mostly to keep the water from freezing during the day.


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## SolarGary

Angie DDD said:


> I just use a standard in tank heater that one of my husband's friends who is an Indianapolis electrician rigged up to a solar panel for us. The solar panel goes on top of the fence post so it gets good light all day and just powers the water heater. Our horses never really drink at night. It's mostly to keep the water from freezing during the day.


Hi Angie,
That's interesting.

Can you provide more detail?
- Climate you live in?
- Size of the PV panel?
- Size of the tank?
- Is the tank insulated?

Gary


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## thesmackdown

Gary,

I sent you an email, but this is probably a more appropriate place to ask.

I have a pig waterer made from a 55 gallon food grade barrel. There is a nipple waterer at the bottom that the pigs can bite and get the water.

I will be keeping the pigs until about January so I need some ideas to keep them with some drinking water.

I am in Western Wisconsin so can expect extended below freezing days.

This is what the nipple looks like: http://www.enasco.com/product/C12883N

Any suggestions?


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## SolarGary

thesmackdown said:


> Gary,
> 
> I sent you an email, but this is probably a more appropriate place to ask.
> 
> I have a pig waterer made from a 55 gallon food grade barrel. There is a nipple waterer at the bottom that the pigs can bite and get the water.
> 
> I will be keeping the pigs until about January so I need some ideas to keep them with some drinking water.
> 
> I am in Western Wisconsin so can expect extended below freezing days.
> 
> This is what the nipple looks like: http://www.enasco.com/product/C12883N
> 
> Any suggestions?


Hi, 
I got the email, but with what I know about pigs, you are likely to get more help here than from me  

If you can work out any way to insulate the tank, that is going to be a big plus. If the water in the tank gets used fairly quickly, just insulation may be enough except for all but the coldest weather. I guess the nipples could be put on an extension pipe to go through the insulation? Don't know how hard pigs would be on the insulation?

This is just a first thought, but even a layer of the Reflectex style (basically aluminized bubble wrap) insulation would help. You would want to stand the layer of Reflectex off the barrel a bit so there is an air gap between the Reflectex and the barrel -- this lets the reflective layer do its thing. The Reflectex website shows some ways to stand the Rflectex off a surface. The top and bottom of the tank could be insulated with a couple circular pieces of rigid foam board, which might serve as places to tie the Reflectex to -- Great Stuff foam in a can would make a good glue to hold the Reflectex in place.

If you have a good sun location, you could paint the south side of the tank black, and work out some kind of glazing -- if it just until January, maybe just poly film would be OK? The other sides of the tank should be insulated.
Given that you are only going to use this until Jan, not sure its worth doing the solar part.

Gary


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## ryanthomas

Angie DDD said:


> I just use a standard in tank heater that one of my husband's friends who is an ----------- rigged up to a solar panel for us. The solar panel goes on top of the fence post so it gets good light all day and just powers the water heater. Our horses never really drink at night. It's mostly to keep the water from freezing during the day.


spam post


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