Mike Jay wrote:Hi Todd, sorry to start with questions, but they could affect the answer...
1. Would the tank be in intimate contact with the ground (to get a bit of heat transfer)?
2. Would you be adding/removing water during the winter?
3. Can part of the tank freeze and it still be ok?
4. What's your average temperature (not high or low) in January?
My initial guess is that there isn't a size that will keep from freezing up on you. All lakes around here are buried fairly deep and still freeze the top couple of feet I know a guy who runs the water department for a decent sized city in central WI. I asked him how they keep water towers from freezing. They do it by periodically changing the height of the water to break the ice that forms and in the process introduce new "warm" 45 degree water to the tower.
Insulating the tank would resist the flow of heat out of the tank but not prevent it. So day after day the temperature will drop to meet some ratio of the ground temp under the tank and the air temp around the tank. IE, if the average air temp is 10 and the ground temp is 40 and 75% of the tank is exposed to air and 25% is exposed to ground, the tank should eventually reach around 17.5 degrees. Insulation would help but I don't think the amount of slightly warm heat from the ground would overcome the loss out the sides.
Side Note: Water towers only have one pipe going up them. Water can flow either up or down. So the water plant just pumps extra water into the main and it forces water back up into the tower. When they slow down the pumps, the water starts to leave the tower as the city uses it.
Phil Gardener wrote:Can you also pick up some passive solar gain for the tank? Maybe as simple as a dark surface. Perhaps a windbreak too!
A sonic boom would certainly ruin a giant souffle. But this tiny ad would protect it:
Got a New Homestead? Here is What You Need to Know to Before You Start a Homesteadhttps://permies.com/t/97104/Starting-homestead-strong-foundation