I picked up a 550 gallon unpressurized tank from American SolarTechnics (Tom in Maine) this spring and am slowly getting it online. The piping is done and now its down to getting the controls done. For some motivation and to check out my installation, I manually opened up a three way diverter valve and started heating it up. It did take its time, but it got up to 155 degrees before I switched it off. I had mounted three thermocouples prior to the installation of the liner (near the top of the sidewall, mid tank level at side wall and tank base) and they definitely show stratification. I will keep and eye on it for a few days and see what sort of heat loss occurs. I have some 1-1/4 piping on the coil sticking up with no insulation so I definitely expect some extra heat loss.
As for the controls, I have a start on them but ran out of DIN terminal blocks for my new control panel. Its somewhat complex as I use a oil boiler as a backup source of heat and the oil boiler runs the zones. The wood boiler when running, heats the oil boiler and locks out the oil burner as long as the water temp is above 140. I realize I have some loss due to keeping the oil boiler hot, but given the capacity of the wood boiler, this has never been a issue, generally my main problem was running out of places to put the heat from the wood boiler. Now that I have the storage tank, I can run the wood boiler at full tilt to heat the house with the excess to storage. The tricky part is that when I am heating the house from storage, I dont want to heat the oil boiler, so the controls are somewhat more complex (and still evolving) and having only one heat transfer coil adds a bit more fun . I have used relay logic versus a PLC and to make it more interesting I have the logic system set up that if the wood boiler master power is turned off, the oil boiler runs as though all the other equipment isnt there. Except for the future servicability, A PLC is the way to go, but at some point if a burner tech needs to deal with it, they understand relays a lot better than PLC's.
One thing real noticable is the need to insulate all the interconnecting piping. The tank is 20 feet away from boiler and there was a lot of heat loss until I got the majority covered.
Once I get my batch of terminal blocks, I will be back at it.
As for the controls, I have a start on them but ran out of DIN terminal blocks for my new control panel. Its somewhat complex as I use a oil boiler as a backup source of heat and the oil boiler runs the zones. The wood boiler when running, heats the oil boiler and locks out the oil burner as long as the water temp is above 140. I realize I have some loss due to keeping the oil boiler hot, but given the capacity of the wood boiler, this has never been a issue, generally my main problem was running out of places to put the heat from the wood boiler. Now that I have the storage tank, I can run the wood boiler at full tilt to heat the house with the excess to storage. The tricky part is that when I am heating the house from storage, I dont want to heat the oil boiler, so the controls are somewhat more complex (and still evolving) and having only one heat transfer coil adds a bit more fun . I have used relay logic versus a PLC and to make it more interesting I have the logic system set up that if the wood boiler master power is turned off, the oil boiler runs as though all the other equipment isnt there. Except for the future servicability, A PLC is the way to go, but at some point if a burner tech needs to deal with it, they understand relays a lot better than PLC's.
One thing real noticable is the need to insulate all the interconnecting piping. The tank is 20 feet away from boiler and there was a lot of heat loss until I got the majority covered.
Once I get my batch of terminal blocks, I will be back at it.
