Domestic Heating with a Biomass Boiler
Discussion
From one of Harry Flashman's threads ( https://www.pistonheads.com/gassing/topic.asp?h=0&... ) where the topic of chopping wood was being discussed, I was asked by ATG to give some more info on my own biomass setup, hence I thought I'd start a new thread so as to not derail Harry's thread.
I'll try to go through it logically (in time), though I'm sure it'll make sense (hopefully) if I get things out of place etc.
We bought our current home in summer 2015 and it was originally heated via an old (1980's) oil boiler and a 1974 oil fed Aga in the kitchen. Part of our home renovation plans was to build a garage and this necessitated moving the oil tank, so we had to look at our heating and water requirements. The lady we bought from estimated that she got through about 4000 litres of heating oil per year, and that was a cost we didn't want to have running for the time we intend to live here (30-40 years), so I started looking at alternatives inc ASHP and GSHP. As our home was built in 1931, it is quite leaky and draughty so ASHP was out of the question and we have too many trees to be able to install GSHP slinkys etc (vertical bore holes would be vastly too expensive). As we have about 4 acres of woodland (sadly all TPOd) it made sense to use a biomass heating system.
From Redleicester and FlipFlopGrif's threads ( https://www.pistonheads.com/gassing/topic.asp?h=0&... and https://www.pistonheads.com/gassing/topic.asp?h=0&... ) - or threads where they contributed, I started looking at a combined pellet log system made by SHT. They do 4 different sized TDA (Thermo Dual Action) boilers and I was recommended to have the 2nd one up in size (25Kw). Whilst I've not been looking at biomass boilers recently (why would I?) the only one that was a fully combined, automatic, web accessible boiler was the SHT TDA, so it means I can load the main burn chamber with logs, make sure there are some wood pellets in the hopper on the side and then just walk away. As and when I run out of heat (in the buffer tank) the boiler starts itself automatically with a hot air system (like a heat gun for stripping paint etc) that blows onto the pellets which ignite and then this in turn ignites the logs in the main chamber. As these logs burn, the boiler controls the water flow around the boiler and then starts heating up 2000 litres in my thermal store. It's a full log gassification boiler that monitors the oxygen in the exhaust fumes, the temperature of the burn, the temperature of the boiler and the temperature of the water circuit - all with automatic overload protection should it get too hot, have a loss of water or any other action that might happen. It also has a holiday mode, so I can load it up before I go away for 1/2/3/4 etc days/weeks and it will turn itself on, start the burn and we come home to a warm house and lots of hot water. Or, I can control it via my laptop/phone from anywhere int eh world I can get the internet.
It's not a small install though! It takes up about 1/5 of my (enlarged) double garage - just under 1 car width in a 7.5m long garage. You need space for the buffer tank (mine is 2000 litres - that 2 tons of water!), expansion vessel (mine is 300 litres - the same as a lot of domestic hot water tanks for a good sized family home), the boiler itself and chimney system, space to store the spare pellets not in the boiler (min are in 25kg bags on a 1m2 pallet) space to store the logs for each burn, and of course, space to be able to get around it to clean it and remove the waste ash (of which there is very little - it gets cleaned about once every fortnight in the winter, far less in the summer).
Our install: it was installed while I was still finishing the garage roof etc and it certainly isn't this clean and shiny any more! -
Cost was ... a lot. By my rough calcs, I expect to break even somewhere between 7 and 10 years - we've had it for 3 years so far. The govt give us a 7 year Renewable Heat Incentive (about £450 every 3 months) for 7 years which is part of my 'break even calculations'. After the break even period, all of our heating and hot water is 'free' subject to 2 stroke and replacement parts/chains for the chainsaw, electricity for the log splitter and my time to process, split, stack, move etc etc the wood in preparation for use about 1 yr later. Oh, and the 1 ton of pellets I bought back in 2017 will probably last me for about 10 years as it only uses on a small handful to start each burn. As and when I'm too old to want to process the wood, I'll build a bulk pellet store where my logs and pellets are currently stacked in the garage, have an auger system fitted and then let it run predominantly on pellets. In the winter, it burns once per day, so that's loading logs once per day and moving bulk logs from the wood store to the garage once per week or if I move enough, once per fortnight. In the summer, it burns about once per 7-8 days as it's just for domestic hot water.
As part of the install, the company gave me a calculation as to how much wood or how many pellets I'd need and I think I'm ahead of the game (seasoning) for the next yr, but it's a constant thought process - what I cut, split and stack now, I can't burn until 1 yr (pref longer) has passed else they could be too wet and I'm wasting energy in the boiler driving off the water.
Old picture of my Log store (I'll try to remember to get a more current one) -
Since moving in, we've had various bits of tree work to trees in the garden and down the drive, so haven't had to 'formally' manage the woodland, it just unwanted wood that I've been processing - happily mainly oak with some lime, cherry, ash and spruce/fir.
4 or 5 oaks recently felled - still to be cleared:
Of the 4 acres of woodland, all of it is covered by TPO (any tree outside of the garden) and about half is also covered by SSSI. We have drawn up a woodland management plan in consultation with Natural England and have made an agreement with a local forestry chap to help us manage it (in combination with another 2 landowners and about 30-40 acres in total). he will fell and maintain the woodland and we will get some of the wood (sufficient for our needs) from the wood he drops. If we didn't have that in place, I'd need to get some formal chainsaw felling training and to get a felling licence - not sure I want to go down that route!
One thing our installation company failed to mention was the fact that we'd need to increase the size of our radiators as the biomass thermal store tends to run the rads at 50-55 deg C, vs a 'normal' heating system that runs around 70 Deg C, thus we need to apply a factor to get more heat out due to the lower flow temps (ASHP uses the whole floor slab but at a much lower temp by way of analogy / comparison). Fortunately we are working our way through the house renovating, so as we do each room, we sort out the plumbing, re-new the rads, install additional insulation (walls and ceilings), sort out the draughts etc, so we are always increasing the efficiency of out heating. The water in the thermal store runs directly into the rads but through a heat exchanger (in the tank - an indirect system) for our hot water. I've hooked it up to a Drayton Wiser 'smart' heating system, so again, from anywhere in the world, I can control the heating requirements which in turn controls the boiler demand.
While we were without central heating one year (winter 2016-2017) while I was building the garage, we only had 2 log burners, one in the lounge (9Kw), a double sided one in the hall/dining room (8Kw) and an electric immersion heater for hot water - that was a challenge! Get up first thing, load/relight the 2 stoves in the house, keep them fed all day (whilst being outside building the garage etc), then load them up at night when we went to bed. It was OK, but not great - but if our boiler ever fails, we know we can heat the house (especially as we've added a lot of insulation since then) until I can get the biomass boiler repaired etc and back up and running - something to think about if biomass is your heat source!
The biomass works for us, with our lifestyle / time availability, but it might not work for you in 'this' form, but there are many tweaks and variations to reduce the workload in keeping it going - mine is very labour intensive - and I'm happy with that. Happy to answer any questions etc on the whole system and set up etc but I can't always promise a prompt reply!
I'll try to go through it logically (in time), though I'm sure it'll make sense (hopefully) if I get things out of place etc.
We bought our current home in summer 2015 and it was originally heated via an old (1980's) oil boiler and a 1974 oil fed Aga in the kitchen. Part of our home renovation plans was to build a garage and this necessitated moving the oil tank, so we had to look at our heating and water requirements. The lady we bought from estimated that she got through about 4000 litres of heating oil per year, and that was a cost we didn't want to have running for the time we intend to live here (30-40 years), so I started looking at alternatives inc ASHP and GSHP. As our home was built in 1931, it is quite leaky and draughty so ASHP was out of the question and we have too many trees to be able to install GSHP slinkys etc (vertical bore holes would be vastly too expensive). As we have about 4 acres of woodland (sadly all TPOd) it made sense to use a biomass heating system.
From Redleicester and FlipFlopGrif's threads ( https://www.pistonheads.com/gassing/topic.asp?h=0&... and https://www.pistonheads.com/gassing/topic.asp?h=0&... ) - or threads where they contributed, I started looking at a combined pellet log system made by SHT. They do 4 different sized TDA (Thermo Dual Action) boilers and I was recommended to have the 2nd one up in size (25Kw). Whilst I've not been looking at biomass boilers recently (why would I?) the only one that was a fully combined, automatic, web accessible boiler was the SHT TDA, so it means I can load the main burn chamber with logs, make sure there are some wood pellets in the hopper on the side and then just walk away. As and when I run out of heat (in the buffer tank) the boiler starts itself automatically with a hot air system (like a heat gun for stripping paint etc) that blows onto the pellets which ignite and then this in turn ignites the logs in the main chamber. As these logs burn, the boiler controls the water flow around the boiler and then starts heating up 2000 litres in my thermal store. It's a full log gassification boiler that monitors the oxygen in the exhaust fumes, the temperature of the burn, the temperature of the boiler and the temperature of the water circuit - all with automatic overload protection should it get too hot, have a loss of water or any other action that might happen. It also has a holiday mode, so I can load it up before I go away for 1/2/3/4 etc days/weeks and it will turn itself on, start the burn and we come home to a warm house and lots of hot water. Or, I can control it via my laptop/phone from anywhere int eh world I can get the internet.
It's not a small install though! It takes up about 1/5 of my (enlarged) double garage - just under 1 car width in a 7.5m long garage. You need space for the buffer tank (mine is 2000 litres - that 2 tons of water!), expansion vessel (mine is 300 litres - the same as a lot of domestic hot water tanks for a good sized family home), the boiler itself and chimney system, space to store the spare pellets not in the boiler (min are in 25kg bags on a 1m2 pallet) space to store the logs for each burn, and of course, space to be able to get around it to clean it and remove the waste ash (of which there is very little - it gets cleaned about once every fortnight in the winter, far less in the summer).
Our install: it was installed while I was still finishing the garage roof etc and it certainly isn't this clean and shiny any more! -
Cost was ... a lot. By my rough calcs, I expect to break even somewhere between 7 and 10 years - we've had it for 3 years so far. The govt give us a 7 year Renewable Heat Incentive (about £450 every 3 months) for 7 years which is part of my 'break even calculations'. After the break even period, all of our heating and hot water is 'free' subject to 2 stroke and replacement parts/chains for the chainsaw, electricity for the log splitter and my time to process, split, stack, move etc etc the wood in preparation for use about 1 yr later. Oh, and the 1 ton of pellets I bought back in 2017 will probably last me for about 10 years as it only uses on a small handful to start each burn. As and when I'm too old to want to process the wood, I'll build a bulk pellet store where my logs and pellets are currently stacked in the garage, have an auger system fitted and then let it run predominantly on pellets. In the winter, it burns once per day, so that's loading logs once per day and moving bulk logs from the wood store to the garage once per week or if I move enough, once per fortnight. In the summer, it burns about once per 7-8 days as it's just for domestic hot water.
As part of the install, the company gave me a calculation as to how much wood or how many pellets I'd need and I think I'm ahead of the game (seasoning) for the next yr, but it's a constant thought process - what I cut, split and stack now, I can't burn until 1 yr (pref longer) has passed else they could be too wet and I'm wasting energy in the boiler driving off the water.
Old picture of my Log store (I'll try to remember to get a more current one) -
Since moving in, we've had various bits of tree work to trees in the garden and down the drive, so haven't had to 'formally' manage the woodland, it just unwanted wood that I've been processing - happily mainly oak with some lime, cherry, ash and spruce/fir.
4 or 5 oaks recently felled - still to be cleared:
Of the 4 acres of woodland, all of it is covered by TPO (any tree outside of the garden) and about half is also covered by SSSI. We have drawn up a woodland management plan in consultation with Natural England and have made an agreement with a local forestry chap to help us manage it (in combination with another 2 landowners and about 30-40 acres in total). he will fell and maintain the woodland and we will get some of the wood (sufficient for our needs) from the wood he drops. If we didn't have that in place, I'd need to get some formal chainsaw felling training and to get a felling licence - not sure I want to go down that route!
One thing our installation company failed to mention was the fact that we'd need to increase the size of our radiators as the biomass thermal store tends to run the rads at 50-55 deg C, vs a 'normal' heating system that runs around 70 Deg C, thus we need to apply a factor to get more heat out due to the lower flow temps (ASHP uses the whole floor slab but at a much lower temp by way of analogy / comparison). Fortunately we are working our way through the house renovating, so as we do each room, we sort out the plumbing, re-new the rads, install additional insulation (walls and ceilings), sort out the draughts etc, so we are always increasing the efficiency of out heating. The water in the thermal store runs directly into the rads but through a heat exchanger (in the tank - an indirect system) for our hot water. I've hooked it up to a Drayton Wiser 'smart' heating system, so again, from anywhere in the world, I can control the heating requirements which in turn controls the boiler demand.
While we were without central heating one year (winter 2016-2017) while I was building the garage, we only had 2 log burners, one in the lounge (9Kw), a double sided one in the hall/dining room (8Kw) and an electric immersion heater for hot water - that was a challenge! Get up first thing, load/relight the 2 stoves in the house, keep them fed all day (whilst being outside building the garage etc), then load them up at night when we went to bed. It was OK, but not great - but if our boiler ever fails, we know we can heat the house (especially as we've added a lot of insulation since then) until I can get the biomass boiler repaired etc and back up and running - something to think about if biomass is your heat source!
The biomass works for us, with our lifestyle / time availability, but it might not work for you in 'this' form, but there are many tweaks and variations to reduce the workload in keeping it going - mine is very labour intensive - and I'm happy with that. Happy to answer any questions etc on the whole system and set up etc but I can't always promise a prompt reply!
Are you in the UK?
No access to mains gas I guess?
We have resorted to a pellet stove for heating too, we had an lpg system that provided hw and radiator heating, astronomical to run on 45kg propane cylinders, cost 98e here in Portugal.
We installed a 24kw stove to the lounge which kicks out 19kw to the rads and 5kw to the lounge, also have a log burner in the lounge if really chilly or for focal point.
Just bought 3 tonnes of pellets and hopefully they will be enough to get us through the winter season. One thing I did do to get the heat into the house a bit quicker was to change out the boiler anti condensation protection valve for one 10 degrees lower and that has seen an improvement.
Pellets cost me 700e for 3 tonnes and I will use about a tonne of firewood too at 100e, plus about 300e of propane, so all in all hw and heat at 1100e a year.
Who is the manufacturer of the boiler?
No access to mains gas I guess?
We have resorted to a pellet stove for heating too, we had an lpg system that provided hw and radiator heating, astronomical to run on 45kg propane cylinders, cost 98e here in Portugal.
We installed a 24kw stove to the lounge which kicks out 19kw to the rads and 5kw to the lounge, also have a log burner in the lounge if really chilly or for focal point.
Just bought 3 tonnes of pellets and hopefully they will be enough to get us through the winter season. One thing I did do to get the heat into the house a bit quicker was to change out the boiler anti condensation protection valve for one 10 degrees lower and that has seen an improvement.
Pellets cost me 700e for 3 tonnes and I will use about a tonne of firewood too at 100e, plus about 300e of propane, so all in all hw and heat at 1100e a year.
Who is the manufacturer of the boiler?
Edited by dingg on Monday 24th August 12:58
Yup, UK based (Gloucestershire) and no mains gas in the village (60 or so houses) so everyone is on oil, bulk bottled gas or other non mainstream systems.
Boiler manufacturer is SHT - an Austrian company but owned by Lohberger - https://www.lohberger.com/heiztechnik/ Search for SHT and you'll get 2 or 3 UK installers
Boiler manufacturer is SHT - an Austrian company but owned by Lohberger - https://www.lohberger.com/heiztechnik/ Search for SHT and you'll get 2 or 3 UK installers
Edited by S6PNJ on Monday 24th August 13:15
Wow. That's quite something!
I can't help but think GSHP boreholes would have been a better option (same impact to radiators, doesn't have to be WUFH), but I'm in awe of what you've achieved and the devotion to it (processing logs).
It does seem incredibly space intensive, but I assume the garage/wood store were exiting structures.
I can't help but think GSHP boreholes would have been a better option (same impact to radiators, doesn't have to be WUFH), but I'm in awe of what you've achieved and the devotion to it (processing logs).
It does seem incredibly space intensive, but I assume the garage/wood store were exiting structures.
What an interesting read and hat doffed for your efforts.
I looked at the same system ten years ago when embarking on our last project. 6000sq ft house but Grade II and Georgian, so single glazed windows throughout. The cost quoted was £60k to get the hot water pipe to the back door so excluding all internal works, (rads and internal controls).
No surprise we opted to put in a new, efficient, oil boiler and a number of log burning stoves instead. Never used more than 3,000litres of oil a year plus our own logs for the stoves.
We had an existing barn that would have housed the kit which as you say can be extensive.
Congrats on getting Biomass to work economically, I couldn't see how it would ever make sense in an old property.
We've since moved to a converted forge which has loads of insulation, U/F heating, rainwater harvesting, private drainage so the bills have dramatically dropped but an extreme way of achieving that result!
I looked at the same system ten years ago when embarking on our last project. 6000sq ft house but Grade II and Georgian, so single glazed windows throughout. The cost quoted was £60k to get the hot water pipe to the back door so excluding all internal works, (rads and internal controls).
No surprise we opted to put in a new, efficient, oil boiler and a number of log burning stoves instead. Never used more than 3,000litres of oil a year plus our own logs for the stoves.
We had an existing barn that would have housed the kit which as you say can be extensive.
Congrats on getting Biomass to work economically, I couldn't see how it would ever make sense in an old property.
We've since moved to a converted forge which has loads of insulation, U/F heating, rainwater harvesting, private drainage so the bills have dramatically dropped but an extreme way of achieving that result!
Evanivitch said:
I can't help but think GSHP boreholes would have been a better option (same impact to radiators, doesn't have to be WUFH), but I'm in awe of what you've achieved and the devotion to it (processing logs).
It does seem incredibly space intensive, but I assume the garage/wood store were exiting structures.
The bore holes would have been about £8k each and I'd probably have needed about 4 (I think - can't really remember).. If I could have bored a pipe line to the nearby (old and probably decommissioned) covered reservoir, then one would probably have done it! I think (at the time) the costs didn't work out for GSHP which is why it was discounted.It does seem incredibly space intensive, but I assume the garage/wood store were exiting structures.
The wood shed already existed but I took time off work to build the new garage with space for the biomass, 2 cars and a small workshop area for me.
eliot said:
I wonder if it’s worth having a system boiler setup for LPG bottles as an emergency backup as I don’t suppose service and parts are going to be rapid in the depths of winter.
I wouldn't want the hassle of having a separate gas boiler somewhere, plumbed into the system, running off 47Kg bottles on standby - we can cope with our 2 internal log burners - plus my wife has a 4Kw gas heater (for her greenhouse) that is hooked up to a 47Kg bottle, so we can always use that!! ha ha! Our installers are in the next county (not country) so support is just a phone call or short drive away, no problems with parts/service/maintenance etc.gred said:
some other stuff, then:
Congrats on getting Biomass to work economically, I couldn't see how it would ever make sense in an old property.
We've since moved to a converted forge which has loads of insulation, U/F heating, rainwater harvesting, private drainage so the bills have dramatically dropped but an extreme way of achieving that result!
Our house has 50mm cavity and in order to get the RHI we HAD to have cavity insulation fitted (that I didn't particularly want). Since buying, we have also insulated the roof with 75mm PIR (we have an attic rather than a loft), installed new double glazing, and 50mm PIR insulation on all external walls (but internally) as we renovate rooms and fibreglass insulation in between ground and first floor (as we do ceilings), so it is much more thermally efficient than even just a few years ago. We also have a septic tank, so no waste water charge and I'm considering (in the future) trying to get our working well hooked up to supply our water, but that might be a dream too far! We are not quite Barbara and Tom (the Good Life) but probably not far off it sometimes!Congrats on getting Biomass to work economically, I couldn't see how it would ever make sense in an old property.
We've since moved to a converted forge which has loads of insulation, U/F heating, rainwater harvesting, private drainage so the bills have dramatically dropped but an extreme way of achieving that result!
Interesting read.
I used to work in Building Services design around 2008 and we were speccing biomass boilers in everything due to RHI.
I believe it's turned into a bit of a scandal since then with empty warehouses being heated just to get the government rebates.
Certainly not a solution for everyone due to the amount of active involvement you need. It's a shame boreholes worked out so expensive and excluded GSHP.
It was also a glaring oversight from whoever sold it to you if they failed to mention the rad requirement, very cheeky as they would have known full what was needed.
I used to work in Building Services design around 2008 and we were speccing biomass boilers in everything due to RHI.
I believe it's turned into a bit of a scandal since then with empty warehouses being heated just to get the government rebates.
Certainly not a solution for everyone due to the amount of active involvement you need. It's a shame boreholes worked out so expensive and excluded GSHP.
It was also a glaring oversight from whoever sold it to you if they failed to mention the rad requirement, very cheeky as they would have known full what was needed.
ChocolateFrog said:
It was also a glaring oversight from whoever sold it to you if they failed to mention the rad requirement, very cheeky as they would have known full what was needed.
Yes, that was (just) one of the things that the installer (owner) pissed me off with! There were a few, but fortunately not too many. The guys actually doing the work were great though.Edited to say: The boiler system as installed had room thermostats that did automatically change the circulation temperature of the water from around 50 to (up to about) 70 - but at 70, there is very little that can be drawn from the thermal store that only starts at 80 deg C or so. Having fitted the Danfos Wiser system, I could manually (set once and forget) change the water circulation temperature but again, I'd lose the 'capacity' of the buffer and it is much more efficient to use lower flow temps and make more use of the full temp range of the buffer, hence the larger rads being better (for me).
Edited by S6PNJ on Monday 24th August 22:30
Really interesting to read, OP.
If it's the same burner doing log and pellet, can it also do wood chip? It's much less "active effort" to make a big stack of long trunks, and then get them chipped up once a year.
"quite leaky and draughty so ASHP was out of the question" - I often hear this, but surely what it means is "quite leaky and draughty so I needed a very large heating capacity". ASHP may still be an option to add in, as it gives you some backup heating capacity, and will also probably cover your heating from during spring to autumn. And hot water in the summer.
If it's the same burner doing log and pellet, can it also do wood chip? It's much less "active effort" to make a big stack of long trunks, and then get them chipped up once a year.
"quite leaky and draughty so ASHP was out of the question" - I often hear this, but surely what it means is "quite leaky and draughty so I needed a very large heating capacity". ASHP may still be an option to add in, as it gives you some backup heating capacity, and will also probably cover your heating from during spring to autumn. And hot water in the summer.
biggiles said:
Really interesting to read, OP.
If it's the same burner doing log and pellet, can it also do wood chip? It's much less "active effort" to make a big stack of long trunks, and then get them chipped up once a year.
"quite leaky and draughty so ASHP was out of the question" - I often hear this, but surely what it means is "quite leaky and draughty so I needed a very large heating capacity". ASHP may still be an option to add in, as it gives you some backup heating capacity, and will also probably cover your heating from during spring to autumn. And hot water in the summer.
It can't do wood chip as such, in that the hopper can only feed pellets due to their ability to be crushed if they get trapped (it's a screw feed system), but as I get a lot of waste bits of wood / bark / small branches etc, I just chip them up (through a Jo Beau M300!), allow them to season / dry out for a while, then just chuck them in the main boiler when I fill it. They don't burn as well, or as completely, so more ash is produced, but at the end of the day, they burn and make heat!If it's the same burner doing log and pellet, can it also do wood chip? It's much less "active effort" to make a big stack of long trunks, and then get them chipped up once a year.
"quite leaky and draughty so ASHP was out of the question" - I often hear this, but surely what it means is "quite leaky and draughty so I needed a very large heating capacity". ASHP may still be an option to add in, as it gives you some backup heating capacity, and will also probably cover your heating from during spring to autumn. And hot water in the summer.
My comments on ASHP is more to do with the fact that I'd lose too much heat too quickly and ASHP wouldn't be able to keep up - plus we wouldn't want the unit(s) outside our home and ASHP is best suited to UFH which we don't have, wouldn't want to retrofit in rooms that were already sorted (floor wise), and also wouldn't work with carpeted rooms, so too many downsides for us to use. When our lounge floor was redone last year (completely dug out), the aim was to fit UFH fed from my thermal store, but when I asked the Company for the heat calcs, it wasn't sufficient (as we wanted a carpeted finish). Their answer - install rads to cope with the additional requirement! Erm, the point of UFH was not to have rads - you couldn't make it up!
Very interesting - I didn't realise you could mix pellets and logs in the same machine. That makes the whole proposition more attractive as I assumed once you were "on pellets" you needed to get them delivered forever. But as you say, the pellet option is a good one if you are away, or too infirm to cut wood. That said, I am working on the assumption that heavy duty wood cutting will stop me becoming infirm for as long as possible.
Our house is currently heated by a solid fuel Rayburn which handles most of the winter quite happily. If it gets really cold, then we have an 11 kW Clearview stove at the other end of the house that makes everything very tropical in short order. When we renovated and extended the place we put wet underfloor heating in which runs on an electric boiler which gives us the ability to keep the house warm if we are not there to load wood.
Our house is currently heated by a solid fuel Rayburn which handles most of the winter quite happily. If it gets really cold, then we have an 11 kW Clearview stove at the other end of the house that makes everything very tropical in short order. When we renovated and extended the place we put wet underfloor heating in which runs on an electric boiler which gives us the ability to keep the house warm if we are not there to load wood.
rxe said:
Very interesting - I didn't realise you could mix pellets and logs in the same machine. That makes the whole proposition more attractive as I assumed once you were "on pellets" you needed to get them delivered forever. But as you say, the pellet option is a good one if you are away, or too infirm to cut wood. That said, I am working on the assumption that heavy duty wood cutting will stop me becoming infirm for as long as possible.
Not the best picture, but you can just about make out the pellets at number 8 (hopper not shown) being fed then igniting. The pellet flames light the logs (or just provide the heat) and heat produced is extracted through the various bits of heat exchanger. The flames burn downwards (in the main chamber) so the logs at the top don't ignite until they get lower down in the main chamber.
Evanivitch said:
Out of interest, how much ash do you get out of a biomass burner and does it just all go on the garden?
The burn chamber is approx 34cm x 34cm x (probably) 50 or 60cm. The spec claims 130 litres. About a wheelbarrow of logs (depending on how big your barrow is and how full you fill it!). If that lot of logs burns each day, I'd need to empty the ash after about 3 weeks. I keep 'records' of when I've empty the ash, put in pellets, cleaned and serviced it etc and looking back, it seems to be about 2-3 weeks, but closer to 3 most times.I use a 6 ton log splitter (mine is made by Handy - https://www.thehandy.co.uk/machine/6-ton-electric-... and I've removed all the guards so I can get larger rings onto it. It manages to split just about all I throw at it (and I throw a LOT at it!). I used to have a chinese 4 ton splitter which was ok but more recently it started to struggle a bit. The splitters in this range (4-6 or thereabouts) are pretty much all the same - Screwfix, Handy, Titan, Mow Direct etc etc) are all very slight variations on the basic chinese model - mine was a Longli ( http://www.longli-industry.com/log_splitters.html ) but it looks visually similar to pretty much every other 4 ton splitter.
I tend to split quite small as it helps season quicker and also makes it easier to stack with less gaps (which won't help it season quicker...). Wood will typically season by 1" per year, so a 2" square (or diameter) log will take approx 1 year (1" from each side to meet in the middle). Obviously this depends on where you are in the country (and hence the average humidty levels) time of year, time the wood was felled (in Sprig, sap will be rising so it will have a higher % of water) and lots of other variables.
You see log piles where they are just thrown onto a pile, but then you can't get to the oldest logs, so this allows me to fill from the front to the rear of the wood shed, moving to the next gap along to the left and then use from the front to the rear, again moving right to left, so I know I'm always using the oldest logs first (except within a stack where clearly the oldest ones are at the bottom and I'm picking from the top). I tend to stack in a 2x2 grid, and as the pile grows, I stick one or two 'logs' midway between the piles, to join the stacks and make them more stable. I can get through a 'strip' (front to back of the shed, 2 x 2) each month in winter, so a fair bit! Must be about 3.5-4m3 of split wood by a rough calculation per month.
I tend to split quite small as it helps season quicker and also makes it easier to stack with less gaps (which won't help it season quicker...). Wood will typically season by 1" per year, so a 2" square (or diameter) log will take approx 1 year (1" from each side to meet in the middle). Obviously this depends on where you are in the country (and hence the average humidty levels) time of year, time the wood was felled (in Sprig, sap will be rising so it will have a higher % of water) and lots of other variables.
You see log piles where they are just thrown onto a pile, but then you can't get to the oldest logs, so this allows me to fill from the front to the rear of the wood shed, moving to the next gap along to the left and then use from the front to the rear, again moving right to left, so I know I'm always using the oldest logs first (except within a stack where clearly the oldest ones are at the bottom and I'm picking from the top). I tend to stack in a 2x2 grid, and as the pile grows, I stick one or two 'logs' midway between the piles, to join the stacks and make them more stable. I can get through a 'strip' (front to back of the shed, 2 x 2) each month in winter, so a fair bit! Must be about 3.5-4m3 of split wood by a rough calculation per month.
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