Wood chip burners

kravist

Im in the process of planting a couple of hundred trees which i hope will supply carbon neutral fuel for my home in a number of years. Apart from being useful for stove/open fire burning, is it realistic/viable to chip ones own wood for a wood chip burner and can anyone recommed a particular model?
It would be even better if in the meantime the wood chip could double as a wood pellet burner. All advice appreciated!!

CJhaughey

A big chipper is a big investment, what size trees are you talking about chipping?
Do you have a chainsaw, are you competent with a saw?
What species of tree are you planting? Softwood/hardwood?
Open fires are not very efficient in making the most of wood energy, stoves and log burners are a lot better.
Have you got a covered seasoning area to dry your split wood? Have you got enough area to dry chips?
Lots of questions and more info required.

zippy 99

kravist wrote: »

Im in the process of planting a couple of hundred trees which i hope will supply carbon neutral fuel for my home in a number of years. Apart from being useful for stove/open fire burning, is it realistic/viable to chip ones own wood for a wood chip burner and can anyone recommed a particular model?
It would be even better if in the meantime the wood chip could double as a wood pellet burner. All advice appreciated!!

Woods chips burners are useless.

You will see a big return to open fires in the near future, the revolution is already starting.

blackbox

zippy 99 wrote: »

Woods chips burners are useless.

You will see a big return to open fires in the near future, the revolution is already starting.

I hear a lot of complaints about wood-chip burners, but I don't have any personal experience.

However I can tell you that open fires are not the alternative.

To burn wood efficiently you need a purpose built wood-burning (or multi-fuel) stove, and you will need to operate it properly. Open fires are hopelessly inefficient - you will need about four times as much fuel to achieve the same comfort level.

Also, if you are thinking of making your own wood chips, you will need some facility to air dry them. Logs you can simply stack under cover for 1-2 years.

kravist

CJhaughey wrote: »

A big chipper is a big investment, what size trees are you talking about chipping?
Do you have a chainsaw, are you competent with a saw?
What species of tree are you planting? Softwood/hardwood?
Open fires are not very efficient in making the most of wood energy, stoves and log burners are a lot better.
Have you got a covered seasoning area to dry your split wood? Have you got enough area to dry chips?
Lots of questions and more info required.

Hmmm, i obviously haven't thought this through as much as i should!

Small chipper i'm sure would do, but totally incompetend with a chainsaw.
Planting all native species, but i honestly dont know if they produce hard or soft woods. Will happily take advice!!!
Unfortunatly ground isn't good enough for ash, will have to stick with alder birch and the likes mostly.
I dont as yet have a covered seasoning area, but have plenty of space to develop one.
Drying the chips: I had planned on getting a wood pellet burner, storing the silo/pellets in a building with a dump radiator to dry and keep dry the pellets. would this serve a similar purpose for chips?
thanks in advance for all advice!

Cuauhtemoc

Was thinking of getting this woodchip boiler. ETA Hack

Is over 90% efficient and though i don't see it now on their website i'm pretty sure it can run on wood pellets as well. Will double check that.

The plan is to use src (short rotation coppice) willow (good link here on wiki )
Coppiced willow will be easy enough to chip as well.
While waiting for that i'll buy the pellet or chip.

Only hold back now is how much the Eta will be. Dear i'm thinking.

Hope this is some help.

C.

blackbox

kravist wrote: »

storing the silo/pellets in a building with a dump radiator to dry and keep dry the pellets. would this serve a similar purpose for chips?

I don't know what you mean by a dump radiator - what heats it?

kravist

blackbox wrote: »

I don't know what you mean by a dump radiator - what heats it?

A dump radiator is basically a radiator put into the room, buliding where you are storing your wood pellets. Rather than waste excess heat, people often put an extra (dump) radiator to keep the pellets from getting damp. It's centrally heated!

CJhaughey

My thinking is that if you are serious about chipping and drying, you will need a large area with racks made of wire mesh or something similar that can be stacked to allow air to circulate around the chips.
For chips you don't really need heat, firewood will dry if stacked out of the rain and where air can circulate around it.
I would imagine that a racking system that consisted of wooden frames and wire mesh in 1x1m squares or something similar would be the way to go, allow say 75mm between racks to allow good air circulation and chips should dry quite fast.
Chippers get expensive when you start talking large diameter wood, anything over 70mm is going to need quite a lot of HP to drive.
Firewood is still the easiest way to heat a house, especially when you look at the amount of work needed to prepare it.
Cut, split, stack, burn.

blackbox

kravist wrote: »

A dump radiator is basically a radiator put into the room, buliding where you are storing your wood pellets. Rather than waste excess heat, people often put an extra (dump) radiator to keep the pellets from getting damp. It's centrally heated!

You still haven't explained where the energy comes from to heat the radiator, but I suspect you are going to use a significant amount of your energy from burning the chips. This would not be efficient.

To burn wood efficiently, you need to air dry unless you have some source of heat that is going to waste - and if you have that, you should consider how that can be used to heat your house directly.

I'd go with CJs suggestion of burning logs rather than chips - it will take a couple more years to get your trunk diameters large enough to commence coppicing, but should be more efficient in the long run (and less capital outlay).

NB. better to let them get big enough to split rather than burning as round logs. They dry much quicker when split.

kravist

blackbox wrote: »

You still haven't explained where the energy comes from to heat the radiator, but I suspect you are going to use a significant amount of your energy from burning the chips. This would not be efficient.

Yes, you're 100% correct there. It was just someting an "Installler" advised me to do.

Thanks for the advice guys.

Basically, i already have a wood burning stove for heating my sitting room and as much of downstairs as possible.
Im looking for the best solution for central heating to accompany that. I wouldn't like to have a stove in every room, bedrooms etc, for obvious fire hazard reasons etc.
So, can i take it that the best solution is to burn the timber i produce myself in my sitting room, and thereafter heat the rest of the house with a wood pellet burner, burning commercially produced pellets?

Forgot to say, my stove does not have a back boiler.

jawlie

kravist wrote: »

Yes, you're 100% correct there. It was just someting an "Installler" advised me to do.

Thanks for the advice guys.

Basically, i already have a wood burning stove for heating my sitting room and as much of downstairs as possible.
Im looking for the best solution for central heating to accompany that. I wouldn't like to have a stove in every room, bedrooms etc, for obvious fire hazard reasons etc.
So, can i take it that the best solution is to burn the timber i produce myself in my sitting room, and thereafter heat the rest of the house with a wood pellet burner, burning commercially produced pellets?

How many years will it be years before your timber is ready to burn?

Although Wood Pellet burners were all the vogue in 2006, there are considerable problems with them. Have you considered an air to water heat pump? http://www.systemlink.ie/air-heat-pumps.asp

CJhaughey

How about if you get slash from forestry operations and chip that?
That burns well and can be got for free or very little, some of the bigger stuff can be split and dried for burning.

blackbox

One other word of caution, depending on where you live.

I planted a good few ash trees several years ago, but they were devoured by deer. If there are deer in the locality, you will need to fence them out. Rabbits can also be a problem for the first year or two.

boomshackala

zippy 99 wrote: »

Woods chips burners are useless.

You will see a big return to open fires in the near future, the revolution is already starting.

Rubbish
A good brand will perform year after year hassle free with only twice annual cleaning.

Regarding wire mesh drying chip etc...don't do it. The chip dries itself by exothermic reaction thereby losing some of its integral energy (you will see steam rising). Dry in log form for a year or more and get a contract chipper in to chip 10 tons per year. This is the amount you will need

A chipper will never pay for itself unless you get into contracting

It will take forever to establish a forest. A willow plantation will end up costing you more money than buying in chip. But if you buy it in, you need a mechanism for loading the silo.

Conclusion
Wood chip boilers are a great investment for you if you have a forest already which will yield you 10 tons p/a, or if you are a contract chipper, or if you have access to cheap or free logs..or recycled wood etc. Otherwise you don't have an econimical investment.

Just my 00.2c

If you build a drying shed with a clear plastic roof, you could dry the wood using sunlight.

Especially in the summer.

Cleck for shiny objects acting as lenses though.

Mothman

blackbox wrote: »

One other word of caution, depending on where you live.

I planted a good few ash trees several years ago, but they were devoured by deer. If there are deer in the locality, you will need to fence them out. Rabbits can also be a problem for the first year or two.

And grey squirrels. they're starting to decimate my 9yo sycamore, the ash will be next...

dhaslam

Instead of using wood chip it is probably better to use an ordinary wood stove with back boiler. In place of automation you can store heat overnight using a large cylinder as a heat store. It is also important to have a well insulated house because otherwise the volume of timber used can be very high. The heat store should preferably be heated by gravity. Timber should be cut in one winter to be used the following year because timber will wase a lot of energy producing steam if not dry.

blackbox

dhaslam wrote: »

Instead of using wood chip it is probably better to use an ordinary wood stove with back boiler. In place of automation you can store heat overnight using a large cylinder as a heat store. It is also important to have a well insulated house because otherwise the volume of timber used can be very high. The heat store should preferably be heated by gravity. Timber should be cut in one winter to be used the following year because timber will wase a lot of energy producing steam if not dry.

I have experience of woodburners both with and without back boilers, and would be reluctant to recommend a back boiler.

My stove without the back boiler works much better and consumes less wood for more apparent heat output (no - I didn't do a scientific measurement). It is much easier to keep the stove WITHOUT the boiler at the higher temperature needed to burn the wood cleanly (no smoke & clean glass).

Your comments on getting the wood dry are spot on, and two years is even better with hardwoods. Not only does damp wood consume enegry creating steam, it also produces creosote that blackens your glass and coats your chimney (and is toxic).

Regarding the heat store, both of my stoves will stay hot overnight without any additional fuel so that the room is still warm in the morning. There is an option for slow overnight burning, but I find that this isn't really necessary.