Linking solid fuel (wood burning) and gas boilers

I thought it was no obstructions between cold feed into boiler and hot outlet with vent to F&E tank. This can accommodate a pumped supply to boiler but if the boiler has a high flow resistance then pump over to F&E tank becomes a problem.

AJH

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AJH
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This condition is met by having a closed stove burning dry wood with a well controlled air supply.

This makes things more complicated as while you can modulate the woodstove within limits not many have a means of varying the output between water and space heating, most of the simple ones solve the problem of firebox quenching by having a small heat exchange surface for the DHW. Gas condensing boilers favour a low return temperature, wood boilers don't so to get good efficiency on the wet side more sophisticated wood burners sense exhaust temperature and blend return and output to prevent condensing conditions in the fire side.

AJH

Reply to
AJH

I quite like these with the removable ceramic panels, I've only worked on Divina dry ones (IIRC wet is not compliant in uk). Beware spilled pellets remaining lodged on the flue. I would retrofit an aluminium screen between hopper and workings, thick baco foil should work.

AJH

Reply to
AJH

I do have a free supply of wood logs from the local golf club, they usually make bonfires of these as it costs to tip them.

Started this thread after reading a previous thread discussing a report on comparative fuel costs and carbon emissions from the The Solid Fuel Technology Institute link below

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has wood logs at the lowest cost and carbon emissions, it just go me thinking.

Reply to
penvale

Talking of which, is there any way of using chipper output for heating? A tree surgeon uses a nearby field to store the results of his surgery and there must be 50 tonnes of the stuff. he gives it away, and occasionally gets the farmer to spread it on the fields. Surely there's a better use than that (we take a small amount for use as mulch)?

Reply to
Huge

Thanks for the link. Pellets cost nearly twice what they suggest for almost everybody. Unless you are particularly remote, logs will cost you twice what they suggest too. Anthracite at 300quid/tonne - I wish!!!

Definitely get a log burning stove. Without question it will reduce your carbon footprint (if you care), heat your house, and provide a beautiful focal point. Attaching a boiler will reduce its efficiency, and cost an arm-and-a-leg.

T
Reply to
tom.harrigan

Dunno about pellets & logs (I only think it's worth using wood if you don't have to pay for it!), but our coal merchant has just sent a flyer with anthracite large nuts at 249GBP/tonne with 15% off if you buy before the end of August.

Reply to
Bill Taylor

There are fan blown boilers that can utilise sawdust..Ive seen themn at 'country shows'

Really more suitable for heating larger areas though.

Reply to
The Natural Philosopher

Well there is always

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payback time though.... Rick... (The other Rick)

Reply to
Rick

Would have to agree with you on the Dunsley Baxter Neutalizer, to me (engineering backgound although not heating and plumbing) it just does not look like a good solution, requires a lot of plumbing at least one extra pump and moterized valve and suspect probably more to make it work with any efficiency.

Have received and information pack this morning from Heating Innovations Ltd about the H2 control panel. First impressions are that it looks a like a proper engineer designed it.

First you have to understand that solid fuel boilers are most efficient between 55 and 70 deg. C, automatic boilers are made to run at higher temperatures, around 82 deg. C.

Basically, when only the solid fuel boiler is on it works in just the same way a normal pumped solid fuel central heating system. The same when just the gas boiler is on, it works in the same way as it does on a normal system, as if there was no secondary boiler.

Two feeds to the H2 panel, one from the solid and one from gas boiler and a valve which allows one or the other to pass it never mixes the two feeds.

When the gas boiler is on and the solid fuel boiler is lit, the flow from the solid fuel boiler is simply diverted into the return of the automatic boiler which then lifts the temperature to it's own level, this way none of the output of the solid fuel boiler is wasted. When the system reaches an adjustable preset temperature, the automatic boiler is automatically shuts down or when the temperature drops switched on again.

Did that make sense ?

The person I spoke to a Heating Innovation said they were in the process of having a website build but they would have to get back to me with the URL. Tried a google but did not find it.

Reply to
penvale

There are several stoker heads available but they tend to be large, I'm only familiar with a "Veto" head, these are basically an auger feeding into a firebrick trough, the heat output of which is fed into a conventional (large) boiler. The trouble is these prefer dry woodchip and arboricultural chips are high moisture content and contain buds, leaves and other fines. The ash from these fouls heat exchange surfaces worse than stem woodchip.

I "service 3 such devices and their commissioned costs varied from~GBP300k for a 500kW(t) boiler to undisclosed megabucks for a

200kW(t) woodwaste boiler in tandem with a 1MW(t) woodchip boiler as part of a green planning gain for a commercial establishment.

IME if you want to burn this stuff cheaply it's easier to burn it in a batch loaded device that heats a large thermal store rather than have the expense of a proper woodchip boiler.

AJH

Reply to
AJH

Have been on the phone to Heating Innovations this morning, managed to get hold of Mike Smith the designer of the H2 control system, anyway here is the link I promised.

Link to H2 control system website

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Reply to
penvale

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