Wood Burner Oil Boiler FrankenHybrid

[jackpreacher]

I'm not sure this will interest too many in this forum, but, since you lot are stuck with me and this is the only forum I have ever joined then this is where it's going

SYNOPSIS

1. GOAL: Converting a cheap Wood burning stove to a high efficiency boiler stove for next to nothing.
2. In January 2012 we ripped out our two oil boilers as they were costing far too much to feed
3. Last week we converted a cheap Wood stove into a high efficiency boiler by doing the following:

(I) lining the firebox with refractory insulation and firebricks
(II) Sealing the stove (they leak air terribly) with fire clay
(iii) Running the flue pipe into the bottom of the old oil boiler, having stripped the boiler of everything but the, er, boiler. The boiler is worth £75 on EBay.
(iv) burning really hot fires and getting around 400 litres of 95C water every 2.5 hours that is supplied to the main central heating return pipe which.......
(v) ...reduces the load on the beefy Wood Pellet boiler that replaced the oil boilers earlier this year.

If there is interest I'll post a run down of the project here with pictures. None of it is with Building Regs approval but then I know it's safe........


.........was that noise?....

[Wee Jim]

I would like to see more!

[Wazza]

Ya Jack show us da fanken heater ......Please ..........

[ianoz]

Up Here ,{Down Here } The Heat problem is getting rid of it .So if ya reserch comes up with a wood fired Air Con ,let me know .

[Wazza]

Up Here ,{Down Here } The Heat problem is getting rid of it .So if ya reserch comes up with a wood fired Air Con ,let me know .

Well what about Gas powered ,replace the gas with wood and there you have it ... http://www.originenergy.com.au/2965/...r-conditioning

[jackpreacher]

Ya Jack show us da fanken heater ......Please ..........

OK, you asked for it!!!

Firstly, the layout. The living room is adjacent to the boiler room with a 400mm stone/rubble/block wall in between. A large hole
was made.
Drilling Hole through to Living Room.jpg

..and from the living room...
Through to Boiler Room.jpg

Then the stove is in place..
Empty Stove.jpg

...and connected..
Stove Connection.jpg

[jackpreacher]

All the photos went on in one big blob. Sorry about that. There is text on the photos explaining a bit about how it all went together. For anyone reading my thread on fixing my Volvo EC15B this is the reason for the delay in boxing that job off. Isn't it always the way.

[jackpreacher]

How it works

1. The flue gasses pass through the boiler and out up the flue, heating the 40 odd litres of water in the boiler in the process.
2. The water reaches 65C at the top where a pipe thermostat is triggered and the Grundfos pump is energised.
3. The heated water passes through a 45kW flat plate heat exchanger and transfers its heat into the return water from the main central heating boiler.
4. The water returns to the boiler about 30C cooler and gets reheated by the flue gasses.

SAFETY FEATURES


If the pump fails the water will reach 103C in 15 minutes, depending on the size of the fire in the stove. When that happens the water boils into the Feed&Expansion cistern and overflows to the drain. Cool water from the F&E then refills the boiler.
Proper wood stove boiler installations have a heat dump radiator installed in the expansion pipework but I decided to test my system to boiling point as the installation is in a holiday rental property and I needed to see the system boil over. It behaved like a gentleman and cooled itself automatically, so, no heat dump required, but I wouldn't recommend that to anyone else!!

[jackpreacher]

Performance Update

Last weekends visitors stayed for 3 nights and burnt a barrow full of dry logs in Frankenboiler.
Whilst they were enjoying a 'real' fire they were basically heating the whole of the 8 bedroomed property. In the past we would have supplied the firewood as a matter of course.

The property is centrally heated by a 15kW wood pellet boiler which normally gets through 60kg of wood pellets a day in cold weather and the internal temperature set to 18C. With Frankenboiler in the loop the wood pellet consumption dropped to 25kg per day over the 3 days.

It works

Thats it then.

....and sorry to our Southern Hemispherical Friends......I have no idea how to cool with burning wood, but with solar panels and a heat pump, now that's a different story

[jackpreacher]

Frankenboiler's new coat

Today we placed a dozen thermal bricks on top of Frankie () to see if he could retain heat overnight, a la Masonry heater.
The thermal bricks were recovered from a bunch of night storage heaters this guy was 'freecycling'. They cost a fortune normally so the half pallet (700kg) of bricks was worth the effort of dismantling from the storage heaters and carting back home.
Masonry heaters work on the principle of storing heat in stone/bricks/tiles, or anything solid and dense, as opposed to water based thermal storage.

I turned the radiators off in the lounge this morning so the only heat source overnight will be whatever heat is stored in the bricks. The fire went out around 21:00 and it's -7C outside. The lounge is HUGE..probably 15mx8mx7m ....a converted barn.

TBC

[jackpreacher]

WOW!

Amazing improvement in performance!

After a couple of really cold nights and no radiators on in the lounge, Frankie kept the temperature at approximately 18C without any more fuel in the firebox than would normally be used. The heat storage bricks were still too hot to touch by 09:00 the following morning and continued giving out heat most of the morning before I filled the firebox around midday and kept a small, hot fire going until around 21:00.

Photos to follow in the morning.

TBC

[jackpreacher]

Here are the two rows of storage heater bricks just stacked on top of the Wood stove:

Frankie's Storage Heater Coat.jpg

..and here is the firebox lined with 6 inches of insulated firebricks on the sides and 2 inches against the back:

FrankieB's Firebox.jpg

We will build a Masonry heater out of the stove and tile it make it fit in. Ok, it won't be a proper masonry heater but we'll still extract a higher proportion of the energy than previously.

Cost so far: £25.00: All the storage heater bricks/firebricks were free. The boiler was already here, the copper plumbing came from off-cuts. The pipe thermostat is the only thing purchased.


TBC

[jackpreacher]

Soot, soot and more soot..

FrankenBoiler started smoking back 2 days ago. Terrible smoke in the lounge. It turns out that the baffles in the old oil boiler have gradually sooted up as they are designed for a 5" flue whereas FrankieB has an 8" flue. So, after removing the baffles and lighting a fire the draught is loads more powerful and the water gets up to temperature even faster. I think the firebox temperature is around 500C but that is using an infrared temp sensor - no idea how accurate it is but the front of the stove is frighteningly hot when open to reload wood.
I'll do some empirical data testing from Monday, but my gut feeling is that overall wood consumption has reduced at least 30%, both in pellets for the main boiler and firewood or FrankieB.
Another advantage over a regular wood stove is that the temperature of the lounge is ambivalent as opposed to boiling hot when he stove is alight. This eliminates 'heat conditioning' whereby a hot room makes all the other normal temperature rooms appear cold - does that make sense?

The masonry thermal mass has been built and tiled so the whole stove plus masonry weighs in at an estimated 500kgs. I'll add photos tomorrow - on my iPad at the moment and can't see a way to use the uploaded.

[Wazza]

So how do you move your heat from Franken heater Jack ,is it Hydronic panels system or do you have a pipe network laid under the floor ?.
I would love a heated slab in my house, but cutting up the floor and laying the pipes isn't really an option .

[mogman]

Now this is a very interesting piece of equipment thanks for sharing it with the rest of us

Mog.