Joining a wood gasifying boiler and an oil heating system

copper12

Hi lads
I had an open’ oil fired heating system.
I am in the process of changing this system to a heating system where by the oil will be the backup system; and the a wood gasifying boiler will be the primary heating system
I have changed the oil heating to a sealed system
The wood gasifying boiler will be combined with a 2000lt buffer tank this will be an open system.
This is a totally DIY job while I am not a plumber I know enough to get by and I am familiar with heating systems .

heinbloed

As far as I understand your post you're working on a domestic heating system(2000l buffer tank). Have you calculated the energy demand of your building?It's usually cheaper to install a good insulation incl. tested airtightness then having and maintaining two heating systems.Most wood gasification boilers have a higher output then needed in an insulated home. Maintenance costs for two boilers (just the anual check-up!) are easily €200.-/a for the two, without fuel storage and other costs......

copper12

The house I built myself and is well insulated
I have not had a calculation done on the heat loss. I don’t believe they are that accurate .
The maintenance of the two systems, will be minimal the wood boiler, will mind itself;
There is not a lot that can go wrong with these boilers
Any problems will be with the stats and the fan; they should last a few years’ before they need any attention.
The oil I have to pay for; the wood is free

copper12

Here’s the storey so far
I have changed the heating system to three zones
Zone for HW
Zone for up stairs
Zone for down stairs
Flash programmer with LED heating and hot water
System zone 5
Minilex wiring centre
The oil side of things seems to be working ok
I should have the wood gasifying boiler up and running soon

copper12

I have the system up and running.
Wood boiler gasifying, laddomat working ,returning water to the boiler; at around 65C.
Boiler set at 80C, draft regulator set at 80C, working in tandem with the boiler thermostat, almost closed when the boiler reaches 80C; laddomat doing exactly as it says on the tin; recirculating water; until it reaches 72C; and then allowing water, to flow to the buffer tank.
The copper cylinder, that I have used for the heat exchanger, and to help to maintain stratification, seems to be working a lot better than expected; and maintaining stratification; when the heating zones are calling for heat .
There is some smoke from the flu, when starting from cold; lasts about fifteen minuets, it then clears’ when the boiler reaches its operating temperature’ their’s no sign of smoke when the boiler is gasifying.
I am waiting for a control thermostat, from America that has a long enough probe, to fit between the EDPM lining and the insulation ; however when I checked the buffer tank; the flow and return from the heat exchanger; was hot’ and there was only a degree or two difference’ between the top of the tank and the temperature of the pipes; so I used flow and clipped on a cylinder stat; this enabled me to get the system operating .
So here is how the system works’
The real boss thinks she’s cold’ and turns on the heating’ if the timer has not got there first
A signal goes to the minilex’ which sends it to the room stat or hot water cylinder stat ; if there’s a call for heat, it sends it back to the minilex; the minilex starts the pump for the zone; and a signal is then sent to the boiler control, in the minilex, which intern sends a live 220 volt; to the [cylinder pipe stat] if the temperature in the buffer tank; is higher than the temperature set on the pipe stat; then the pump for the hea exchanger starts, and the zones are fed from the buffer tank; if the temperature is lower’ than temperature set on the pipe stat then the oil boiler and pump starts. simple as that
I am pleasantly surprised that it is working so well; I will have to tweak, a few things over the next few weeks to get it working just right.
The only concern that I have is if the pond liner; will stand up to the changing temperature; it was the thickest liner I could get at 1.10ml

copper12

hope this works
The Johnson Control Digital Thermostat 80$; has arrived
something similar here would have cost a lot more; I have installed it’ and it has enabled me, to be much more accurate, in how I control the buffer tank and the oil boiler .
I will post some pictures along with some explanation, as to how I ended up with a wood gasifying boiler,

The first image’ is of my existing 90000 btu oil boiler’ I installed in 1998, the last fill of kerosene cost 78 cents a litre; that was back in April. I recon the cost of heating my home 2500sq feet; for the winter, would be anywhere between’ 2000 Euro 3000 thousand Euro’ depending on the type of weather we would have .
I initially was looking at a wood burning stove; that I could install into; an existing fire place’ and after looking at a large number of stoves .I almost settled on a Hercules wood burning stove’ with a back boiler’ that I could combine, with the existing oil central heating system, the average price in this country’ was around 3000 Euro; that was just for the stove’ removing the existing fireplace’ and installing the wood stove. combining it to the heating system; would have cost another 1500 to 2000 thousand Euro, I recon; and that’s with me doing the installation .
Searching the web; I came across sites and forums; that got me interested in wood gasifying boilers.
Trying to source a wood gasifying boiler; in this country, the cheapest wood gasifying boiler; I could come across; was costing in the region of, 4000 and 5000 thousand Euro; with the addition of a buffer tank; the cost had risen to about 8000 or 9000 thousand Euro
http://www.woodenergy.ie/iopen24/pub/ccn08_gasifier.pdf wood energy gives an estimated cost of 16000 thousand Euro
These cost’ were I felt was way to expensive, and would be well beyond my reach; plus the fact that it would take long time’ before I would have recouped the cost; decades even
So I set about trying to reduce the cost to a minimum; using recycled material; and some hard work.
So that is how I ended up here; with a wood gasifying boiler, and the prospect of using no oil, or very little for heating and hot water .

This is the wood boiler 85300 BTU; about twice the size’ of the existing oil boiler’ in size, not heat output
This boiler I got in Poland; along with a laddomat; and some other fittings; for 3330 Euro delivered here;
to Ireland

system zone and minilex; I used to simplify the wiring and zone heating . I could have got it cheaper; if I were living, in an other country, but we live in the rip off republic; so I had to purchase them here.
While I am not happy with the cost; I am happy with there performance; it did make it easier to combine all the zones

Buffer tank; is made with 4x2 timber and 8x4 sheets of ply; insulation industrial type; again all salvaged .
The only thing I had to pay for was the EDPM lining
Here’s a picture of the 2000l tank; with the lining, and the pipe work, from the wood boiler, and the flow and return for the heating system; the automatic air vent, I removed as it was allowing air into the wood boiler .

The boiler’ and the laddomat connected; the laddomat’ I feel is an essential addition; to the system, and makes the boiler’ more efficient; I am very pleased with this item’ 200 Euro cheaper to get in Poland than here

Dual coil copper cylinder; reclaimed from scrap yard; used to stratify the buffer tank; and as a heat exchanger, for the heating system.
The 1” connection, normally the hot water outlet; I connected to the boiler; hot water from the boiler enters the tank’ and comes out; the thru the holes drilled into the tank on top; also true the connection where the emersion heater would have been. This keeps the hot water on top of the tank’ while it is charging, I have two censers, bought of EBay; one about six inches below the water line; and another, six inches above the bottom; of the tank, while charging’ there seems to be about a 15 degree difference; maintained’ when charged’ there seems to be a difference of 20 degrees . So stratification’ seems to be taking place; and maintained, while heat is being drawn off for the heating system . I recon there’s about thirty or forty feet; of 1” copper coil inside the tank; this I have used as the heat exchanger; I combined the two coils; and have the flow and return; connected to for the heating system; this seems to be working’ and I don’t think I will be changing anything here.
The tank’ is held in place by two galvanised bars; the serve two purposes; one to keep the cylinder’ just below the surface of the water; and two; to hold the tank together strengthening the top of the tank .
The bull wire; is slipped inside garden hose; to help prevent galvanic corrosion

6” insulated flu don’t know the price for this yet; my son and son-in-law; fitted this’ could cost a few hundred Euro, or a few pints. I will have to pay for the material.
But the labour:cool:

jonny-b-

Hi, your project is very good, well done.

Do you mind me asking was it an atmos boiler you went for?

Do you find yourself using a lot of logs and how often a week do you fire it up?

copper12

Thanks for the complement
Yes the boiler is a ATMOS Generator DC 25GS
After looking at a lot of boilers; this for me was the one’ most suited’ and it was at a cost’ that was very reasonable
I wasn’t looking for a boiler’ that had to relie on to much on electronics ; one that could operate without electronics’ would be even better
I feel the atmos’ has enough controls to operate safely’ is easily maintained’ an repaired if required .
Although being familiar with other types of boilers’ there’s very little that can go wrong with this type of boiler’
The amount of wood it will burn’ depends on how the boiler is operated’ its early days yet
In my situation; I think I overestimated the amount f wood; I would need by at least 25%
I built a 2000l tank; thinking it would be more than adequate; 3000l would have been even better

copper12

Hi lads just an update
Doing some work around the garage yesterday; so I planed to let the buffer tank; temperature drop just to see how things would work.
I have the Johnson Control A419ABC set at 45c; I want to get as mush usable heat as possible, out of the tank. They domestic heating’ had been on for two hours’ the house was comfortable about 18c; all zones calling for heat.
The radiators’ were fairly warm to the touch’ enough to heat the house;
if left on long enough, and providing the temperature outside, was not to low
Oil boiler kicked in at 44c; as soon as it kicked in; I lit the wood boiler’ it took about 35 minuets’ for the boiler, to reach operating temperature; by this I mean the laddomat opened; allowing water to flow from the buffer tank’ to the boiler.
The boiler was gasifying’ about ten minuets’ before the laddomat opened .
As soon as the tank temperature reached 45c; the oil boiler turned off’ and the heat for the rads’ was being taken from the heat exchanger
The wood boiler; was more than capable of supplying the heat for domestic heating; while also charging the buffer tank
,The heating ran for seven hours last night. and three hours this morning; at the moment 16.16 pm the tank temperature is 75c at the top; and 61c at the bottom.
One full burn accomplished this
I will not need to light the boiler today.

copper12

19 October 2008 10:32
Tank temperature top 53c bottom of tank 41c
So I lit the boiler Friday at around 16.00 from just one burn I had heating Friday night Saturday morning and evening and this morning
I will recharge the buffer today I am well pleased with the way things are working

samoht

Hi Copper12,
I am looking at gasification boilers at the moment and I like your setup, particularly your DIY accumulator tank. I am extending my house and hope to install the boiler in a utility room but the size of accumulator tank would pose a problem, then I thought I could build an insulated tank like yours underground. The wooden structure of the would be well supported by the surrounding earth and an 8' X 4' X 4' tank would have a capacity of 3,400 litres. Apart from the task of excavating the hole in the ground, can you see any issues in designing the tank underground, e.g. pump size to circulate water?

If you're going for an underground tank, it may be easiest to cast a concrete shell in situ and then place some rigid board insulation around the sides followed by the liner.

I used one of those 1000litre bulk liquid containers, I covered it with 100mm rigid insulation around the sides, 50mm cut to fit between bars of the steel cage. 50mm around the sides then a plywood outer cover.

The cover is held firmly in place by some strong lengths of timber to ensure that the tank doesn't "balloon" the polypropalene liner starts to lose it's strength @ 80C.

On top I've put 400mm of rockwool, I use this for solar with future plans to add a small wood burner to the system.

copper12

I cannot see any problems with building the tank under ground as you say
The way I would g about it would be to excavate the hole keeping the soil at least a meter away from the sides we don’t want the hole collapsing on you
Once the hole is dug fill the bottom of the hole with pea gravel to a depth of six inches
Build your frame 8x4x4 lower this on top of the pea gravel it doesn’t need to be reinforced at this stage fill the sides again with pea gravel up to half way this will stop the form moving place your insulation inside the form and your liner inside this
Two weighed check valve will stop the boiler draining into your tank
The wooden form is really sacrificial but it should last a few years probably longer than the liner

rsheehan

Hi cooper12

How is the Log Boiler running for you now? from your earlier posts you said that you had 3 days hot water from one burn! are you still getting this level of efficiency or are you using more wood now. Id be very interested to here an up data on how its been running as I am looking to install one my self in a new build.

It looks like a class system and your description of how you sourced it and installed it was very interesting.

copper12

I am very happy with the boilers performance
It is very easy to clean
Depending on what I burn’ determines how often I have to clean the ash’ from the boiler
The cold spell over the week or so; meant I had to burn once a day’ usually in the evening’ this would mean that the boiler; ran at its most efficient’ charging the buffer tank’ while also heating the house
So you could say, for one burn, I get a full days heating with enough left over for the morning’ when the heating’ is timed to come on for two hours’ this ‘depends on how cold it is outside .
Overall, I am very pleased with the boilers performance, as for the DIY buffer tank’ and heat exchanger’ this has performed much better than expected, I believed it would work’ just didn’t expect it to work as well as it dose,
The boiler will burn any type of wood , while soft wood and hard wood are preferred it will burn laminates, Argus, and Telephone books, as well’ basically if its wood it will burn.
the oil boiler has kicked only once’ or twice’ and this was only for an hour or so
So no problems to date; while the burner is supposed to hold 130 litres’ of fuel you would never get this amount into it’ the most you would get in. would be about 100 litres of fuel.
I am not really concerned about the amount of wood; I burn, as I get it for free, I am only concerned about burning it; at it’s most efficient’ and getting the maximum out of each burn.

samoht

Copper12 & Dolanbaker - Thank you both for your constructional ideas for the underground tank. Some further concerns that come to mind are:

The wooden structure may not ba a practical option for U/G tank because of ground water, dampness etc rotting wood. Also not sure if performance of insulation would be impacted by external ground dampness. Perhaps the concrete idea is worth considering.

What lifetime do you expect to get from the plastic sheeting?

Copper12 - You thought that the 25KW boiler could handle a 3,000 litre tank instead of the 2,000l. Would this require more than a single log fill to heat?

Final question - I am wondering what the noise level is from these boilers with fans etc operating as I plan to install in a utility room.

copper12

samoht wrote: »

The wooden structure may not ba a practical option for U/G tank because of ground water, dampness etc rotting wood. Also not sure if performance of insulation would be impacted by external ground dampness. Perhaps the concrete idea is worth considering.


Copper12 - You thought that the 25KW boiler could handle a 3,000 litre tank instead of the 2,000l. Would this require more than a single log fill to heat?

Final question - I am wondering what the noise level is from these boilers with fans etc operating as I plan to install in a utility room.

The wooden form’ is like I said sacrificial
If you are going to build one in concrete then you will need one
As for the insulation’ wooden form’ damp proof liner’ insulation’ then pond liner in that order
Boiler in the utility room? there will be some smoke’ escape when refuelling’ no mater what make of boiler’ and there will be a smell’ in the room, from the boiler’ of wood smoke
As for noise they are surprisingly quite
For 3,000lt tank this would need at least three to four burns to reach a temperature of 80 degrees’ once this is done then it is unlikely you will lower it below 50 degrees’ before you will need to light the boiler again
Going on my own experience I would think it could handle 3000lt

samoht

copper12 wrote: »

Boiler in the utility room? there will be some smoke’ escape when refuelling’ no mater what make of boiler’ and there will be a smell’ in the room, from the boiler’ of wood smoke
As for noise they are surprisingly quite

Would the level of smoke and smell from these boilers be on par with say a stanley range?
I am considering locating in utility room because I live in a semi-D and garage is converted. I have ruled out building a small external boiler house because of the flue length requirement of 3-4M.
Does anybody know of instances of boilers installed in habitable areas?

copper12

Wood gasifying boilers are efficient; only if installed’ and operated efficiently’
By this I mean, combining the boiler with a sufficiently large buffer tank
If you cannot operate it like; this then you would be throwing your money away

samoht

I dont fancy the idea of paying around €2,000 for a commercial accumulator tank. Further to the thoughts expressed on this thread on DIY accumulator tanks here is another idea for critical appraisal.

To maintain good stratification in a tank, one of a number of factors that promote this is a tank with good vertical height relative to its width and depth, therefore I propose to build a 2,400 litre tank measuring 3.5ft X 3.5ft X 7ft height. EDPM pond liners have been used in other DIY examples on this forum but there is a question about the longterm realibility of the EDPM with the hot water.
I plan to construct the basic form of the tank with marine ply. The inside on the ply box will be sealed with layers of fibreglass matting and resin. The box will then be cased in 100mm of phenolic insulation and finally an outer box of marine ply to complete the structure.
The tank will be secured to a wall with steel brackets.
For the inlets and outlets from the tank I am hoping that I will get a sufficient seal around the fittings given the limited scope for tightening with the plywood wall.
All critical replys welcome.

copper12

Samoth
The pressure and forces on a thin tall tank; are completely different to a long and short tank
Other than an issue’ of the middle of my tank bending outward’ from the pressure’ easily solved’ drained the tank’ fitted a bit of angle iron’ refilled the tank’ problem solved’ I have had no other issues’
There are some good video’s on you tube; about fibreglass pools. Others on designing and building big fish tanks; it’s where I got some of my ideas
Give you some idea of how it’s done
Box iron’ as far as I know’ is not all that dear; I would build the outer case of this; and them marine ply; insulation; another of marine ply; then liner’ or in your case fibreglass
Any connections’ can only be made to the marine ply and fibre glass; as there will be movement’ thermal and otherwise’ you will have to allow for this; your right about stratification; tall and thin’ is better than long and short’ but if you are going to build in timber; then you should really do the maths’ as to the stresses that the tank will be under
Hope it works out for you

I have one suggestion, use two bulk liquid containors one stacked on the other with a couple of large diameter pipes connecting them together.

Not a good as a single tank, but it should still stratify (eventually) depending on how the flow % return are connected.

Doctor_L

A friend of mine plans to use a milk bulk tank for his buffer tank. They can be picked up second hand.

Any opinions?

copper12

Bulk milk tanks; stainless steel' don’t come cheap
I spent a lot of time going around scrap yards; looking for a tank' that would hold two thousand litres
Stainless steel; best I could come across was 1500 euros; then you would have to modify it to suite your needs
Cheaper to go for a purpose provided buffer tank

You might be very lucky and find a farmer who wants rid of one

samoht

Deleted User wrote: »

I have one suggestion, use two bulk liquid containors one stacked on the other with a couple of large diameter pipes connecting them together.

Not a good as a single tank, but it should still stratify (eventually) depending on how the flow % return are connected.

Where would I get the tanks you are proposing above and what price are they likely to cost bearing in mind the cost of a commercial accumulator tank is €2K?

They are commonly called bulk liquid carriers, often used for one journey only.
They can be obtained from many farmers co-ops for about €100 or less, if you're lucky there may be a local industrial user who has "some around the back" that you can take away.

Davidm1348

Hi Copper12, I enjoyed reading your thread on installing the gassifying boiler a while back, but I can't seem to find it again now. I'm new to this forum can you point me the right way.

I am just planning the renovation of an old house that is more or less a ruin, so I was thinking of using an internal wall as a heat store. I reckon there is at least 10 cubic metres of granite there and I was thinking of adding a layer of concrete with heat-exchange pipes embedded (like a UFH system only vertical) and then insulating it. What do you think? Is anyone talking about a solid heat store? Regards, D.

Carlow52

Davidm1348 wrote: »

Hi Copper12, I enjoyed reading your thread on installing the gassifying boiler a while back, but I can't seem to find it again now. I'm new to this forum can you point me the right way.

I am just planning the renovation of an old house that is more or less a ruin, so I was thinking of using an internal wall as a heat store. I reckon there is at least 10 cubic metres of granite there and I was thinking of adding a layer of concrete with heat-exchange pipes embedded (like a UFH system only vertical) and then insulating it. What do you think? Is anyone talking about a solid heat store? Regards, D.

The reason water is used as a heat store is at least 2 fold:
1 it is plentiful, non corrosive, 'free' etc

2: the more important reason is that it has, for a commoner gardener product, one of the highest specific heat capacities, of 4.2 joules per gram per degree Celsius

see http://en.wikipedia.org/wiki/Specific_heat_capacity#Table_of_specific_heat_capacities

If u look at the table u will see that granite is pretty crap, and the values shown assume ideal transfer. The density of granite allows it perform well for the Volumetric heat capacity measurement but is still half that of water.
http://en.wikipedia.org/wiki/Volumetric_heat_capacity

Stone/solid walls are usually found in unheated conservatories where they absorb heat from the sun

On a personal note, if I had a internal granite wall I would NOT plaster it:)

teepee

Hi ,Now that you have been using the log boiler for over a year now . can you estimate the quantity of timber you would need per yearsoftwood or hardwood per meter cubied ? some estimate 20 m3 per year of softwood but i cant see how . what do ye think ?