Frozen valves are a major, major bummer in my world and on most (all?) homesteads. The winter of 2014-2015 was cold in New York. There are still patches of snow on the ground around here, but I feel confident about sharing my technique for preventing a really critical valve from freezing.
I raised 21 pigs through the winter on an untypical ration of hay and whey from greek yogurt manufacturing. I gave them a few other minor things, but the two staples were fermented hay and yogurt. Yogurt whey is mostly water, but it has enough salts dissolved in it to prevent freezing right at 32 degrees. In my experience it begins to freeze in the low 20s and gets pretty solid when the temps drop into the teens. Both January and February days this year only occasionally climbed up into the teens, which meant I needed to keep the valves on my whey storage tanks from freezing. The site I picked to locate the pigs’ winter house and the whey storage worked well from a delivery standpoint, but there was no electric power within 3000 ft unless I was willing to install a meter and a drop for an outlet. So lots of whey sitting in a tank for up to 5 weeks at a time in the bitter cold… how to keep it flowing?
Insulation and heat from mother earth. The tanks were set on a leveled and smoothed pad so the bottom was in direct contact with dirt. I didn’t haul in gravel or any sort of special base, but I did pick over the pad site fastidiously in search for rocks that could puncture the bottom. A few feet down the average temperature of my soil is about 48 degrees F. My hypothesis was that if I insulated the tanks out four or more feet latent heat in the ground would wick up to the fluid and hopefully over to the valve. I began by staging large round bales around the perimeter of the whey tank. The tanks are 9 feet tall though, so I then piled loose hay and wood shavings on top of the big bales in a slope up to the shoulder of the tanks. Loose hay settles a lot, so I refreshed the piled part twice as winter progressed, though by the time of these photos it had sagged again.
I left the tops uninsulated. Around the valve I built a wooden box with a removable lid lined with blue foam. Either side of the box got a big bale and then a bridge of scrap wood between the bales. This "bridge" is still intact on the left-most tank in the above photo.
I could then carry the pile of insulation to the shoulder of the tank even directly above the valve. The cavity under the scrap wood bridge allowed me to pack more loose hay in ,which I could remove and return each time I needed to access the valve, a twice-a-day chore.
In January, after several very cold days and nights I arrived one morning to a mostly stuck valve. I could still open it just enough to let some whey flow, but it took a long time to fill the trough. After fretting for an hour or two about how to solve this issue I hit upon a solution. When the forecast called for night-time temperatures below 10 degrees F I would heat a small bucket of water and place it inside the box right next to the valve. I was probably a little conservative about how often I refreshed the bucket (every chore time for a few weeks in February when it was brutally cold), but considering how catastrophic it would be for my pig chores if I couldn’t get the whey to flow I thought the extra caution was warranted. I only used this bucket trick on the valve of the tank I had tapped for feeding. The other(s) just drifted in under the snow, and I never had a problem with the valves freezing so long as the tanks were full of whey when they sat for an extended period of time.
The lid on the box was critical for top performance. I forgot to put it back on a few times, and on those days the box was dramatically cooler by the next chore time. With a lid, residual heat could often be felt when I reached for the valve.
The whey never froze very deeply inside the tanks. For one thing it arrives at about 100 degrees and 6,000 gallons of liquid has a huge residual store of heat in it. Even with nights well below zero the whey took four or more days to fully cool. The ice on my streams only got about 4 inches thick, so even if the whey froze to that depth I was not worried about losing much of it to ice. The incoming fresh whey could then thaw any residual chunks.
I think the principles of thick insulation and passive ground source heat could be applied to other situations. I don’t know the size of the smallest tank this technique would work for. I suppose it would depend on how often the liquid was refreshed. Other tweaks that help - cutting into a bank, southern exposure, wind blocks. My valves are sited on the southeast side of my tanks because the prevailing wind on my farm comes from the northwest, especially the really cold Alberta Clippers we had the pleasure of experiencing so many times this winter.
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