Suggestions on a perfect setup

[mousebndr]

Hi Guys

We are renovating our hydronics system, getting rid of the old boiler and getting a Seton

Our house is pretty large with 22 steel panel radiators rated at 50kw total. The house is old and cold, dont have any real figures on heat loss. We are at 900m and in winter it hovers between -2 at nights and 5 deg C in the day.

The goal is to be be able to start the fire morning and night and have storage to be able to cater for when the boiler has completed the burn. Maybe only once a day in the shoulder seasons. This seems to be very common over there in the US but here in Australia people don't seem to be doing it with local wood boilers. Our current wood boiler is a dog, needs to be fed every few hours or the house goes cold.

Alternatively the boiler will just burn for 8-10 hours while still providing adequate heat.... But I wonder if this is actually possible.

So the plan was to get a seton w180 and 3700 L (1000 gal) of open storage with a copper coil hx.

I got a million questions but I guess most pressing is...
- Will it work Would love to hear some opinions.
- What's a good plumbing setup for this, something simple with minimal hx in the storage.
- Assuming copper pipe in the storage, what's a good diameter and how to you determine the length

I am sure there is more but les see how that goes

Thanks!

David

 

[woodsmaster]

First of all do some searches on here about the seton. Some like it, many do not. As for storage I'd go pressurized if possible.
Try to find some kind of pressure vessel. Propane tank or tanks would work. This will save you from buying the copper coils that are very expensive, at least in the states they are. You will also get more usable heat from pressurized storage. You also should
do a heat loss calc. to see how much storage you need to last 12 hr. on design day. All I can think of for now. I'm sure others will give some ideas soon. Welcome to the Hearth !

 

[Gasifier]

Hi Guys

We are renovating our hydronics system, getting rid of the old boiler and getting a Seton

Our house is pretty large with 22 steel panel radiators rated at 50kw total. The house is old and cold, dont have any real figures on heat loss. We are at 900m and in winter it hovers between -2 at nights and 5 deg C in the day.

The goal is to be be able to start the fire morning and night and have storage to be able to cater for when the boiler has completed the burn. Maybe only once a day in the shoulder seasons. This seems to be very common over there in the US but here in Australia people don't seem to be doing it with local wood boilers. Our current wood boiler is a dog, needs to be fed every few hours or the house goes cold.

Alternatively the boiler will just burn for 8-10 hours while still providing adequate heat.... But I wonder if this is actually possible.

So the plan was to get a seton w180 and 3700 L (1000 gal) of open storage with a copper coil hx.

I got a million questions but I guess most pressing is...
- Will it work Would love to hear some opinions.
- What's a good plumbing setup for this, something simple with minimal hx in the storage.
- Assuming copper pipe in the storage, what's a good diameter and how to you determine the length

I am sure there is more but les see how that goes

Thanks!

David

I would second Woodsmaster and also recommend pressurized storage.

The guys on here need some stats David. How large is pretty large? How many square feet are you talking? When you say the house is old and cold? If you rated the insulation in the house. Would it be poor, fair, good? Are you going to heat your domestic hot water, which I would suggest, as well?

 

[willworkforwood]

... The house is old and cold, dont have any real figures on heat loss. We are at 900m and in winter it hovers between -2 at nights and 5 deg C in the day. ....Our current wood boiler is a dog, needs to be fed every few hours or the house goes cold. .....

How about insulation and infiltration elimination, before investing in a new boiler? Unless your losing tons of heat to faulty underground lines, it sounds like your house is leaking like a sieve. Are you able to DIY? If so, you can make huge progress on this front for a modest amount of $$. Even if you can't get to the insulation part right now, reducing infiltration can be ultra-inexpensive and highly effective. And even if you can't do any DIY, pro work would be paid back many times over, assuming you're going to be in that house for a number of years.

 

[stee6043]

Welcome to the board And here I thought your whole country was sunny and warm year round. ha.

Do you have any local building codes that pertain to boilers? Around here what type of boiler we buy and even what kind of tanks we use can be dictated by local laws/codes. Pressurized storage is usually more efficient and easier to plumb but it some places you need to have ASME tanks which are much more expensive than most home-built open tanks.

To answer your questions:

1.) Yes, it certainly can work.
2.) Check out the "simplest setup" sticky in the boiler room for a good high level overview of plumbing.
3.) Do a search here for HX coils. Lots of people build them themselves...

 

[dogwood]

David, I'm not sure what gassification boilers may be available to you in Australia. You may have access to some of the better European models we don't have available stateside. If I were you, I'd find out what is available and research the models for how they best meet your needs. You could look at manufacturer reputation, cost, parts availability, BTU's produced etc. There are a lot of comments on this site and elsewhere where useful input can be found on various models including the Seton. Look at the Tarm Biomass site for plumbing schematics. Here's a link, (broken link removed to http://www.woodboilers.com/admin/uploads/public/WoodBoilerPlumbingSchematic0111Web.pdf) Here's another link to some more schematics from the Atmos site (broken link removed).

I went with pressurized storage, a used propane-type tank, so I wouldn't have to worry about oxygen in the water, having to add chemical additives periodically, plus no need for a heat exchanger. In your situation if you went presssurized, you'd just pump your stored heated water directly into your panel rads. I definitely wish I had your panel rads so I could do just that, instead of in my situation using a water to air hx. Panel rads are just coming into the market here stateside. However, others successfully use unpressurized storage for various reasons. Plenty of info on this site on that subject. It would be interesting to know what brand boilers you do have access to in Australia, if you wouldn't mind posting that. Good luck. There's a lot to learn on the whole subject of wood boilers and their installation. People on this site are great for helping you out in that regard.

Mike

 

[mousebndr]

David, I'm not sure what gassification boilers may be available to you in Australia. You may have access to some of the better European models we don't have available stateside. If I were you, I'd find out what is available and research the models for how they best meet your needs. You could look at manufacturer reputation, cost, parts availability, BTU's produced etc. There are a lot of comments on this site and elsewhere where useful input can be found on various models including the Seton. Look at the Tarm Biomass site for plumbing schematics. Here's a link, (broken link removed to http://www.woodboilers.com/admin/uploads/public/WoodBoilerPlumbingSchematic0111Web.pdf) Here's another link to some more schematics from the Atmos site (broken link removed).

I went with pressurized storage, a used propane-type tank, so I wouldn't have to worry about oxygen in the water, having to add chemical additives periodically, plus no need for a heat exchanger. In your situation if you went presssurized, you'd just pump your stored heated water directly into your panel rads. I definitely wish I had your panel rads so I could do just that, instead of in my situation using a water to air hx. Panel rads are just coming into the market here stateside. However, others successfully use unpressurized storage for various reasons. Plenty of info on this site on that subject. It would be interesting to know what brand boilers you do have access to in Australia, if you wouldn't mind posting that. Good luck. There's a lot to learn on the whole subject of wood boilers and their installation. People on this site are great for helping you out in that regard.

Mike

Cheers mate, there is no one who sells gassification boilers here in oz that I can find. Have been looking for years now.

The only boilers on sale are what you would call OWB I think where there is a wet bladder around a firebox, terrible really since the water always puts the fire out towards the end of the burn cycle. Plus fireboxes are small so you need to sit by the thing and feed it constantly.

I liked the Seton because a) I understand how it works so I can fix it if it breaks, and b) it's got few moving parts so there are no issues with 240v, c) Fred is willing to ship to us Not one other boiler manufacturer in the states even answer our emails.

Seems to me the trouble with the Seton comes from idling, where with the storage I am assuming this wont happen? (well much)

David

 

[mousebndr]

The guys on here need some stats David. How large is pretty large? How many square feet are you talking? When you say the house is old and cold? If you rated the insulation in the house. Would it be poor, fair, good? Are you going to heat your domestic hot water, which I would suggest, as well?

You got it.. See attached (apologies its mostly metric). House is 4050 square feet everything that can be insulated is. There are places though that we cant reach.

Its an interesting "house". Its actually 3 old buildings joined together to make one house, with a covered courtyard in the centre.

 

[mousebndr]

First of all do some searches on here about the seton. Some like it, many do not. As for storage I'd go pressurized if possible.
Try to find some kind of pressure vessel. Propane tank or tanks would work. This will save you from buying the copper coils that are very expensive, at least in the states they are. You will also get more usable heat from pressurized storage. You also should
do a heat loss calc. to see how much storage you need to last 12 hr. on design day. All I can think of for now. I'm sure others will give some ideas soon. Welcome to the Hearth !

I would love to do pressurised storage, but cant seem to locate a suitable tank. A question I have always wondered is can you just use 8 x 400 L old DHW units. These are pretty easy to grab on ebay now since everyone is selling them off here to upgrade to solar/gas due to govt. grants. But I wondered how much heat you would loose having all these separate tanks.

 

[Pat53]

David, I have a Seton that I built. Altho I like the boiler for the most part, it is not a true gasification boiler. If I had to do it all over again I would get something else. There are many great gasification boilers on the market. Take your time and do the research before buying anything. jmho

Pat

 

[dogwood]

David, sorry to hear no one is selling wood gasification boilers in Australia. I remember from some older posts people were able to order through Kotly in Poland. Try this link, http://kotly.com/index.php?cPath=169&topSsid=2e06d66e47d6ab481994f289997f2901, and click on shipping. They sell Orlan and Atmos wood gasifiers. They indicate on their site they will make arrangements to ship overseas.

Mike

 

[bpirger]

Have you checked on a Garn? Sounds like it would fit your need. It is extremely simple, no moving parts (a motor for a fan). I'm not sure if Dectra has shipped overseas, and it is a big monster. We couldn't be happier with ours.

Are you heating with just wood now? Or gas or oil? How much are you using? From your table, sounds like you have limited insulation...understand access is limited.

Any pictures of your home you'd care to post? It sounds interesting indeed! What is the history of the buildings?

 

[mousebndr]

David, sorry to hear no one is selling wood gasification boilers in Australia. I remember from some older posts people were able to order through Kotly in Poland. Try this link, http://kotly.com/index.php?cPath=169&topSsid=2e06d66e47d6ab481994f289997f2901, and click on shipping. They sell Orlan and Atmos wood gasifiers. They indicate on their site they will make arrangements to ship overseas.

Mike

Thanks - thats a great site. Prices are great!

Question to all - with a true gassifier. Whats the story with moisture in wood? If your burning well seasoned dead firewood (perhaps 10yrs old) will that burn at all?

THey seem to suggest moisture content of 10-25% but whats that mean when your looking at the wood - freshly cut or aged?

 

[mousebndr]

Have you checked on a Garn? Sounds like it would fit your need. It is extremely simple, no moving parts (a motor for a fan). I'm not sure if Dectra has shipped overseas, and it is a big monster. We couldn't be happier with ours.

Are you heating with just wood now? Or gas or oil? How much are you using? From your table, sounds like you have limited insulation...understand access is limited.

Any pictures of your home you'd care to post? It sounds interesting indeed! What is the history of the buildings?

Yes wood is all we got, except for a few electric portable heaters. Gas is big $$ here, never looked at oil. We have 600acres here with plenty of trees so not worried about a supply of fuel.

Have attached some photos, one is when we laid the PEX in the roof to get to one of the radiator locations. It an old farm house built by some of the original settlers in our region.

 

[willworkforwood]

... with a true gassifier. Whats the story with moisture in wood? If your burning well seasoned dead firewood (perhaps 10yrs old) will that burn at all? THey seem to suggest moisture content of 10-25% but whats that mean when your looking at the wood - freshly cut or aged?

Moisture content of a piece of wood is determined by resplitting down the middle, and measuring (with the grain) at the center of the re-split with a moisture meter - 15-20% is optimal for firewood. Splitting and stacking for a year results in 20% for most species, with oak and some others taking longer. Unsplit Dead wood is typically higher than 20%, often much higher. So, if you've been using mainly unsplit deadwood in your boiler, that may be one of the factors why it's such a "dog". You said that everything was insulated as well as possible, but what about infiltration? It can be truly unbelievable how much cold air can come in from a tiny gap (windows, doors, fixtures ...). Do you know what the output of your current boiler is? Is that pex line in the roof well-insulated? If you have underground or any other exposed lines outside of the heated space, are those well-insulated? Although we rail against traditional OWB smoke dragons on this site, they nevertheless do usually heat homes successfully, and have fairly long burn times. So, if you're filling your boiler "every few hours", unless it's way undersized, I don't think that just replacing it with a gasser is likely to solve you current heating issues. JMHO, and good luck whichever way you go. Nice place BTW - looks like something from a movie - I just can't remember which one :lol:

 

[dogwood]

David, you need to get yourself a moisture meter, they're inexpensive. Split a piece of wood you have in half, and look at the moisture content. I'm no expert but from what I've read it takes a year or so for freshly cut wood to age to 20% moisture. Oak takes longer, maybe two years or so. I have some twenty old cut and split locust that I am concerned might be too dry, and burn too hot, so I am going to try mixing it in judiciously with other less dry wood so no disasters happen. I don't know what might happen if the fire gets too hot. On the opposite end of the spectrum with freshly cut wood, you won't get good results because the energy in the wood is spent on boiling off its own moisture content. I think this leads to creosote problems as well. Maybe some others can chime in and give you a more definitive answer on using too dry wood.

What kind of wood would you be burning? No idea of what trees grow in Australia.

Mike

 

[sparke]

I have a Seton style boiler. For the most part I like it. The biggest downfall is when you have to clean the heat exchanger. If you see my most recent thread, I have figured out a decent way around it, but it is still a messy job. The nice thing about a Seton is the fact you can burn un-splt wood. My boiler seems to actually burn "greener" wood more efficiently than it does seasoned wood. It defies the laws of physics, I think it is the fact that dry wood burns faster than the Hex can remove the heat. Green wood doesn't burn as fast , but since the refractory and the inside burn chamber reach 2000* F , green wood doesn't stay green long. I totally agree most of the issues with Seton come from idling. If I am burning green wood, I don't let the unit idle. Green wood = batch burning to my 1200 gallon tank. Dry wood = around the clock burning with only the overheat going to the tank. The tank really shines in the shoulder seasons. We go from 1 fire a day, to 1 fire every 2 days, by late May we burn 1 fire every 4 or 5 days... My feeling is that with a house your size, the Seton will never idle, I almost feel like it may not be big enough to handle your needs at temps of -2C like you mentioned. Talk to Fred about your BTU needs. Either way, as long as you don't let the Seton idle much, and you don't mind cleaning it, I think you will like it. One other thing, keep the plumbing simple, I have seen Greenwood's fail miserably because they were not plumbed properly. Basically all you need is an expansion tank, feed, return w/cold water shock protection, 30# pop off valve, circ. pump, etc... (not counting your existing circ. pumps on the heat zones). If you use a non-pressurized tank, you do not need copper coils, in that case you can separate the boiler side from the tank and use a flat plate heat exchanger. Don't worry Fred sends out decent plumbing manuals w/ pictures : )

All that said, I still would try to convince you to take your time and look for a good gasification boiler. I have to think shipping from EU is way cheaper than shipping from central United States. Although I think Seton's are now manufactured in the mid west. Maybe Fred has a friend that runs a ship out of the Great Lakes : ) Either way good luck!! Oh by the way, very interesting house you have there

 

[mousebndr]

... with a true gassifier. Whats the story with moisture in wood? If your burning well seasoned dead firewood (perhaps 10yrs old) will that burn at all? THey seem to suggest moisture content of 10-25% but whats that mean when your looking at the wood - freshly cut or aged?

Moisture content of a piece of wood is determined by resplitting down the middle, and measuring (with the grain) at the center of the re-split with a moisture meter - 15-20% is optimal for firewood. Splitting and stacking for a year results in 20% for most species, with oak and some others taking longer. Unsplit Dead wood is typically higher than 20%, often much higher. So, if you've been using mainly unsplit deadwood in your boiler, that may be one of the factors why it's such a "dog". You said that everything was insulated as well as possible, but what about infiltration? It can be truly unbelievable how much cold air can come in from a tiny gap (windows, doors, fixtures ...). Do you know what the output of your current boiler is? Is that pex line in the roof well-insulated? If you have underground or any other exposed lines outside of the heated space, are those well-insulated? Although we rail against traditional OWB smoke dragons on this site, they nevertheless do usually heat homes successfully, and have fairly long burn times. So, if you're filling your boiler "every few hours", unless it's way undersized, I don't think that just replacing it with a gasser is likely to solve you current heating issues. JMHO, and good luck whichever way you go. Nice place BTW - looks like something from a movie - I just can't remember which one :lol:

Cheers, thats about what we are burning then. In Oz we burn Eucalyptus. The best is box, best of the best if red box. Burns extremely hot and lasts for a long time.

We only use split wood in the boiler. Usually split the year before and stacked over summer, or we cut into round 500mm sections in the paddock and come back later to split and collect.

Most pipework sits in the roof crawl space (quite big that area) on top of the insulation, there are two runs like the one I showed you that have to get to a radiator that is on a wall with no crawl space. The pex is insulated, generally you cant feel the heat on the outside of the pipe when the water is running though.

The boiler is rated at 50kW, but my question has always been - for how long. I am sure it gets that high in the first hour but then it really drops back. Once that happens the pump starts cycling when the water temp out of the boiler drops below 50 degC. Then the return water from the house gets too cold and puts the fire out.

This is the case even when only running two of the three zones (basically halving the heating needs).

If we fill the firebox with red box before bed, we will wake up in the morning with just coals in the firebox. It would seem that after around 4 hours the boiler stop producing any useful heat. The pump will cycle after 4 hours but the radiators dont get to the needed temp.

 

[mousebndr]

David, you need to get yourself a moisture meter, they're inexpensive. Split a piece of wood you have in half, and look at the moisture content. I'm no expert but from what I've read it takes a year or so for freshly cut wood to age to 20% moisture. Oak takes longer, maybe two years or so. I have some twenty old cut and split locust that I am concerned might be too dry, and burn too hot, so I am going to try mixing it in judiciously with other less dry wood so no disasters happen. I don't know what might happen if the fire gets too hot. On the opposite end of the spectrum with freshly cut wood, you won't get good results because the energy in the wood is spent on boiling off its own moisture content. I think this leads to creosote problems as well. Maybe some others can chime in and give you a more definitive answer on using too dry wood.

What kind of wood would you be burning? No idea of what trees grow in Australia.

Mike

Sorry answered your post trees above. Eucalyptus is the tree of the day in Oz. Creosote is not really a problem, we only burn dry split wood but I would have thought its moisture content was much lower - learn something new every day

 

[jimbom]

....The goal is to be be able to start the fire morning and night and have storage to be able to cater for when the boiler has completed the burn. Maybe only once a day in the shoulder seasons....

I am sure you are aware of this, but it strikes me reading your post that the need for storage would depend on the size of the boiler with regard to your load. This following diagram was posted in comment #9 on the linked forum for evaluation of storage requirements.

https://www.hearth.com/talk/threads/76064/

This graph has nominal boiler size in kW times burning period in hours for an abscissa scale of kWH.
The ordinate is storage volume in liters.
Heat load of the building divided by minimum boiler output for various sizes are depicted by the sloped straight lines.

An example might be a 30 kW boiler that is fired for 5 hours = 150 kWH;
Building heat load of 25kW and boiler minimum power output of 10 kW = 2.5;
Graph reads 560 liters of storage. If in this example, the building heat load was 10kW, 1600 liters of storage would be required.

In other words, if your building can’t use the boiler output, storage has to be available to absorb the boiler output. Or if your boiler is undersized for the load storage may not be useful. Food for thought. I am sure you are way ahead of me on this, but I thought I would offer in any case. I have fond memories of Oz and the people.

EDIT Added linked

 

[willworkforwood]

....The boiler is rated at 50kW, but my question has always been - for how long. I am sure it gets that high in the first hour but then it really drops back. .....

Can you post what you mean here in actual boiler water temps? It seems odd for a boiler with such a high output to heat well for 1 hour (assuming filled up), and then begin to drop off. What size is the firebox? How about flue temps? If you have a flue therm, can you post the flue temps that correspond to the boiler water temps? I'm not trying to steer you away from a gasification boiler with these questions - just trying to find out what your current situation is, and see if perhaps there is some significant issue with your system that could be corrected.

 

[EffectaBoilerUser (USA)]

David,

What species of wood do you have?

The only accurate way to determine the MC of wood is to use a moisture meter.

I'm not sure what ten year old would have for a moisture content but I would expect it to be pretty low. Remember to split the wood before checking with a moisture meter however.

For most wood, a period of 12 months will get it to 15-20% if it is properly split, stacked and covered (just the top only).

I've seen many people make the mistake of placing a tarp over the entire wood pile, all the way to the ground. Obviously, this will not allow the wind and sun to help in the drying process and will trap mopisture from the earth in the wood).

Hope this helps!

Brian

 

[mousebndr]

....The boiler is rated at 50kW, but my question has always been - for how long. I am sure it gets that high in the first hour but then it really drops back. .....

Can you post what you mean here in actual boiler water temps? It seems odd for a boiler with such a high output to heat well for 1 hour (assuming filled up), and then begin to drop off. What size is the firebox? How about flue temps? If you have a flue therm, can you post the flue temps that correspond to the boiler water temps? I'm not trying to steer you away from a gasification boiler with these questions - just trying to find out what your current situation is, and see if perhaps there is some significant issue with your system that could be corrected.

Unfortunately no flu temps, other than by feel. Normal operation it's not to hot to briefly touch. When the boiler overfires (due to the air flap being set to wide) the flu temps can get very hot. No measurements but you wouldn't put your hand near it, I will also kettle a bit.

Water temps are up around 70-80 deg c exiting the boiler when it's in full swing. After a few hours we drop down to 60 then it will go below 50 and the pump will cut off.

http://www.metaldynamics.com.au/hydronicheating.htm this is the unit, it's a 5000 model

 

[willworkforwood]

Unfortunately no flu temps, other than by feel. Normal operation it's not to hot to briefly touch. When the boiler overfires (due to the air flap being set to wide) the flu temps can get very hot. No measurements but you wouldn't put your hand near it, I will also kettle a bit.
Water temps are up around 70-80 deg c exiting the boiler when it's in full swing. After a few hours we drop down to 60 then it will go below 50 and the pump will cut off.

The temps that you posted are not what we usually see for hydronic boilers, but OTOH, I don't know anything about your boiler, aside from what's on their site. From what you wrote, it sounds like the pump driving your load(s) comes on at a low temp - maybe 50*C ? So, I''m wondering, by circulating fairly cool water through the boiler, if perhaps it's struggling for a long time to get a good fire going (due to poor combustion environment), and actually never really does get to optimal output. Being able to almost touch the flue would tend to support the idea that the fire is weak. If what I said is correct, is it possible to keep the load pump off until the boiler has a good, hot fire going? (initially just to test the theory) Again, I don't really know anything about your system - sounds like it might be unpressurized, and maybe operates differently. But, based on your boiler's firebox size, the quality of wood you're using, and your outdoor temps, it just seems like your existing boiler should be doing better than what you're reporting. Also, how about your chimney - any big amount of soot or creosote? Just some ideas, but I could also be barking up the wrong red box.

 

[benjamin]

First of all do some searches on here about the seton. Some like it, many do not. As for storage I'd go pressurized if possible.
Try to find some kind of pressure vessel. Propane tank or tanks would work. This will save you from buying the copper coils that are very expensive, at least in the states they are. You will also get more usable heat from pressurized storage. You also should
do a heat loss calc. to see how much storage you need to last 12 hr. on design day. All I can think of for now. I'm sure others will give some ideas soon. Welcome to the Hearth !

I would love to do pressurised storage, but cant seem to locate a suitable tank. A question I have always wondered is can you just use 8 x 400 L old DHW units. These are pretty easy to grab on ebay now since everyone is selling them off here to upgrade to solar/gas due to govt. grants. But I wondered how much heat you would loose having all these separate tanks.

The hot water heaters would work fine, especially if you can put them where you want the heat anyway so you don't worry about the heat "loss". Assuming large propane tanks aren't readily available, you might still be able to find ammonia tanks that should be common anywhere corn (maize?) is grown. You could try calling whatever places that big grain farmers buy fertilizer to see if they have any old ones to sell.

It sounds to me like your boiler is just too small for your current demand, that 50kw seems awefully optimistic for that unit. Maybe you could estimate actual output by weighing how much wood it burns over a day or a week and guessing an efficiency (50%?).

The Seton will have the advantage of refractory for a higher efficiency and hopefully a high enough output to send the surplus to storage, but it still doesn't have a blower. Unless you have an exceptional chimney, the electricity to run a blower would be the best investment you could make.