Is EKO the right stove

I use a coil in the tank for my setup, and I'll start to get idling as the tank gets above 160 or so.

In my never-so-humble opinion, this issue is one of the strongest arguments for stratification. I think the ideal storage tank would be pressurized and highly stratified - 180 at the top and 100 at the bottom. If you could reduce turbulence and mixing so as to maintain a sharp boundary (thermocline) between the hot water at the top and the colder water below, then you could deliver consistently cool water to the boiler while pumping hot water into the tank. As you do this, the thermocline would move downwards, and you wouldn't see increased boiler inlet temps until the entire tank was full of hot water.

sled_mack said:

If I have a big, notty piece that I can't split any smaller, as long as it goes through the door, it gets burned. But, I do put some small pieces under it, then all around it to try to balance it out. Seems to work OK.

Speaking of chips. I usually get a load of logs delivered. After cutting them, the ground has a nice layer of saw chips. Every year I think "How can I collect them up without stones or dirt, keep them dry, then burn them next year? Seems like a shovel full of those chips, if they were dry, would work very nicely in each load. Anyone else try to capture these chips and use them?

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An easy way to collect the chips while you are sawing firewood is to place a tarp on the ground under and behind you. As you are sawing the chips land on the tarp, at the end of the day you clean off the tarp and you have clean chips!

Craig

VeggieFarmer said:

What sort of heat exchanger are you using - coils inside the tank? Or a flat plate or sidearm? What about the diameter of the feed pipe from boiler to tank?

I am in the processing of spec-ing out a very similar setup (Tarm Solo 40 with roughly 800 gallons of storage) and was assuming the boiler would never idle until the storage reached full temperature. Not so, huh? Or are there ways to increase the heat exchange capacity to overcome this choke point?

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I use a plate hx, 5" x 12" x 30 plate. My boiler is isolated from the storage tank, as the boiler has an antifreeze mix, tank is all water. A larger hx would transfer more heat, but I think there are diminishing returns here. Think of the heat transfer difference when water is raised from 100 to 160 vs 130 to 160 assuming same flow volume - would reduce by 1/2. I don't see this as a big issue due to stratification. Water at the top of the tank may be 160 while 120-130 at the bottom. It is an issue mainly when I drive the tank to 160-150 or so that idling becomes somewhat of an issue, and I only do this when I need the extra heat (when it is -25F outside) or when I'm gone and can't fire the boiler for a day or two.

You'll be able to store fewer usable btus in your tank if your minimum usable water temp is 160, but it might still be worth doing because it still gives you more flexibility in operating your boiler--just not a much as if you had radiant. And you can still use it for your domestic hot water--ideally year-around.

I run water through my baseboards down to 120, but at that temp they're not putting out much. Good enough to maintain temp on a cool day, but that's about it. Fortunately, that's what I need, The tank is hottest in the small hours of the morning when it's coldest outside. During the day as the tank temp drops, I don't need as much anyway. I rarely get my tank up to an average temp of 160.

I thought Baseboards were Radiant Heating? I know you can get them that work down to lower temperatures. But you need a greater surface area, see picture.

Is there much difference in principal between pipes running through the floor versus around the floor?

My interest is from a retroft perspective, in floor is not going to be practical. And it avoids issues with floor coverings and should be a lot cheaper.

Standard fin tube baseboard are actually convector's. Other areas besides floor install would be walls or ceiling, without floor height or covering issues.
Will

TRACTORMAN said:

I've seen what looks like a short loop close to the stove, is this used to keep the inlet temp above a certain level? Sorry if these questions are basic. Is the temp of the water coming out fairly constant?

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Yes - the short loop is for inlet temp protection. Too cold causes condensation and corrosion.

I think most wood boilers essentially give you a temperature rise based on flow rate, so the outlet temp will be a certain amount - perhaps 20 degrees - above the inlet at a given flow rate.