# Insulated stock tank with solar heat collector



## commonsense (Jun 1, 2008)

New thread--no more hijacking 

For the last three or four years, we've insulated our stock tanks with composting manure with some success, but the boxes were at the point of needing to be rebuilt this year. Since we had to build boxes anyway, we decided to go with a different design altogether. 

After reading about Solar Gary's solar-heated stock tank, I wanted to use that idea and adapt it to incorporate a steel stock tank. We painted 118 gallon steel tanks black on one side, built a super-insulated box, including an insulated floor, with a partial cover--about two thirds of the tank is covered, with one third remaining open for the horses to access the water at all times.

The tank is oriented with the long, black-painted side facing south, and that side of the tank box has a clear panel to allow the sun to hit the side of the tank and transfer that heat to the water in the tank. There is a 5-6 inch space between the side of the tank and the clear panel. 

We put another piece of insulation (pink, 2" foamboard) on top of the tank, creating an airspace all around the tank that heats up when the sun shines. 

We have had pretty cold temps for this time of year--0-2 degrees overnight, teens to low 20's during the day, so we've had a chance to see the tanks perform already. 

We do get a thin layer of ice on the top of the water overnight, but it is only 1/4-1/2" thick, and very flimsy ice that breaks with the push of a finger. Last year, we needed to use heavy metal objects to break through the ice that formed each night. 

We don't use any supplemental heating elements at all. We do fill the tanks every other day--we have 6 horses on each tank full time. Overnight, the horses poke a hole through the ice to drink. 

Horses like to "play" with things, so we added a couple of features to safeguard the tanks...hog panels attached to the south side of the box to keep hooves from smashing the clear panel and metal edging to keep busy teeth from destroying the box. We used recycled plywood siding for the outside of the box and bought new 2x4's and foam insulation. We used spray foam to seal off the clear panel and any other potential air leaks. 


Wouldn't pictures be helpful? I can't find my camera.  As soon as I do, I'll add pics that I took during the building phase,and I'll get some pics of the tanks now that they're working.

I'm happy, I consider these to be quite a success!


----------



## SolarGary (Sep 8, 2005)

Thanks CS!

Couple questions:
Is the drinking opening for the horses in the center of top? Or, is one end of the tank open?
Apparently the horses are OK with taking turns at drinking from the limited size opening?

I'm having trouble picturing this part:
"We put another piece of insulation (pink, 2" foamboard) on top of the tank, creating an airspace all around the tank that heats up when the sun shines."

Can you explain that a bit more. I'd wait for the pictures, but I need to get the one I'm doing going today.

Thanks,

Gary


----------



## Trisha in WA (Sep 28, 2005)

SolarGary said:


> Thanks CS!
> I'm having trouble picturing this part:
> "We put another piece of insulation (pink, 2" foamboard) on top of the tank, creating an airspace all around the tank that heats up when the sun shines."


Me too. If the top is covered, how do the horses get to it?
We get only about 2 weeks of steady freezing temps, but it would sure be nice to not have frozen troughs or have to have the tank heater on.
Thanks,
Trisha in WA


----------



## commonsense (Jun 1, 2008)

commonsense said:


> New thread--no more hijacking
> 
> partial cover--about two thirds of the tank is covered, with one third remaining open for the horses to access the water at all times.
> 
> We put another piece of insulation (pink, 2" foamboard) on top of the tank, creating an airspace all around the tank that heats up when the sun shines.


Sorry if this was confusing...the box has a cover with a 22", pretty much square opening. This remains open at all times for the horses to access the water. 

Below the plywood is a piece of 2" foamboard insulation that has a matching opening cut into that. This piece of foam is sandwiched between the top of the tank and the underside of the plywood cover. (let's all hope i can find my camera soon...) 

Since the box is larger than the tank, placing this foamboard over the tank on the inside of the box, creates an airspace around the sides of the tank that is warmed when the sun hits the black-painted side of the tank through the clear panels. The air is trapped by the sides of the box, the sides of the tank, and the foamboard on top of the tank.

does that explanation make things clearer?


----------



## Trisha in WA (Sep 28, 2005)

Much clearer! Thank you!
Trisha


----------



## SolarGary (Sep 8, 2005)

commonsense said:


> Sorry if this was confusing...the box has a cover with a 22", pretty much square opening. This remains open at all times for the horses to access the water.
> 
> Below the plywood is a piece of 2" foamboard insulation that has a matching opening cut into that. This piece of foam is sandwiched between the top of the tank and the underside of the plywood cover. (let's all hope i can find my camera soon...)
> 
> ...


Thanks -- I think I get it now.

Did you also use 2 inch insulation did you use in the north, east, and west walls? (outside the airspace)

Gary


----------



## commonsense (Jun 1, 2008)

We did use the 2" on the three walls, with an additional 1 1/2" white foamboard between the 2" and the plywood--just because it's relatively inexpensive and filled the space created by the 2x4" frame. We used the cheaper insulation on the bottom, 2" again.


----------



## commonsense (Jun 1, 2008)

Ok, so clearly I forgot to continue taking pictures during the construction process (it WAS cold!) but here are a few shots of the framing and initial insulation. I'll get a picture of the tank tomorrow and post that too.


----------



## commonsense (Jun 1, 2008)

Here is one of the tanks currently in use. Overnight, we had single digit temps with wind. The first picture shows the amount of ice that formed overnight. I took these pics at 8:30 a.m. (central) and the sun is just about to start warming the tank. The tank gets good exposure until mid afternoon, around 2:30 or so right now, with sunset starting around 4pm


----------



## SolarGary (Sep 8, 2005)

Very nice! -- Thanks

Gary


----------



## fishhead (Jul 19, 2006)

Could you add a barrier between the center hole left open and the 2 ends that are under the insulation? That should effectively decrease the amount of exposed water surface and maybe gain a few degrees.

Just a thought.


----------



## commonsense (Jun 1, 2008)

fishhead, we thought a little bit about that idea, but I haven't come up with a horseproof solution, and the need to do so isn't that great. We've jumped straight into winter with some really cold temps already (well below normal for this time of year), and I'm happy with the minimal, easily broken ice that the tanks build up overnight. I anticipate even less ice will accumulate when the days begin lengthening, allowing a longer heating time with the increased sun exposure.


----------



## fishhead (Jul 19, 2006)

Yes it does seem the transition from fall to winter was really short.  The last 2 Decembers we've had -20 and I won't be surprised if we don't get it again this winter. It seems like our falls have been extended (60 F in November) and the bitter cold of January has moved forward a month.

The first thing that came to my mind was heavy duty rubber pond liner but that's what I have on hand. It would present a flat surface and be hard for the horse to grab.


----------



## genebo (Sep 12, 2004)

Nice work.

Genebo


----------

