Technical Old wives tales or not

[bugsymike]

A friend of mine had in his home workshop a large wood burning iron boiler similar to some 1950s schools and connected a series of old fashioned cast iron radiator with large iron pipes he had picked up from a farm auction,
Probably not very efficient but he sold logs so fuel wasn't a problem and it certainly made a difference in his very basic workshop/shed.

 

[Cornish Ian]

In previous life I had a PowerMax boiler. This was effectively a hot water cylinder with a fire box across the bottom with heat tubes going through to a cap on the top. A fan fed gas burner fired into the firebox and fumes were taken away from the top. The huge thermal store made it extremely efficient. Radiators were simply tapped from top side via pump with the return fed into the bottom. There was no heat exchange coil on the radiator circuit. Hot water was provided by a high performance copper coil in the top of the cylinder. You got instant mains pressure hot water through that coil without the rattle of a big inefficient burner to flash heat the water. Plumbers hated them because they refused to read the instructions and they were not getting kickbacks to sell Bosh, Glowbum or whatever brand of combi boiler was the latest rave.

It was intended to be fitted upstairs so there would be no thermal syphon effect. Mine was fitted downstairs with an electric valve. The gas burner fired on heat demand, so you "could" fit a second heat source meaning the gas would fire less often. Unfortunately that would be against the gas regulations.

You an get a similar effect with a thermal store cylinder again you need a high performance oil in the top for heating hot water. Some have two coils so you can run a shower and not have it doing annoying stuff when someone opens a tap elsewhere in the house. A pair of side tappings are fed to the gas boiler. A second set can be connected to any other heart source eg solid fuel back burner. The mass of water in the cylinder mess the flows dont affect each other but they do both need a pump and you need another pump for the radiators which also have their own side tappings and pump.

The very top of the cylinder is vented into a feed and expansion tank (bigger is better if you have solid fuel). Cold feed drops into the bottom of the cylinder at the drain tapping.

Does it work? I fitted one at my mothers house (though it was gas only) and halved her gas bills. It stopped the boiler cycling on/off every 20 seconds and dramatically improved its efficiency.

I think the pipework and wiring in my airing cupboard might amuse you.
I’ve a very large tank heated with 3 coils driven by wet solar panels, a wood burner and wood fuelled Rayburn. Also a solar boost feeding excess electricity from our PV šolar panels into the immersion heater and the wet solar pump and control unit on the opposite wall.
On the output side apart from the DHW take off, I’ve made a 4 zone manifold feeding a underfloor system with scrap off cuts of polypropylene pipes from work. This was originally used to dump excess hot water / heat but after insulating under the beams it produces a reasonable background heat and warm floors. It’s grown over the years as we have changed or added things so not laid out as I would have liked if we had planned for all the additions.
Our newer Rayburn has a larger wrap around boiler which produces more hot water so I’m now working on plans to install a plate heat exchanger to feed heat into our central heating circuit which will provide a more instant heat through the radiators.

I used to run the maintenance department of a very large plant nursery and we installed underfloor heating to heat the glasshouses. (That’s where the off cuts of PP pipe came from) As the nursery grew we ended up using a tanker load of gas oil every week in the winter which became a little expensive. We installed 3 MW wood burner and thermal store /buffer tank which saved us a fortune and we had RHI payments as a bonus.
As you say the tank stops the boiler cycling on and off which is even more important with solid fuel of course. Getting the tank through the lanes was quite a task as it was 3 Metres diameter plus the insulation and feet, we had to lift or tie back several trees. It was cut for transport as it was 30 metres long but even with a rear steer low loader some of the corners were tight.

 

[bugsymike]

I think the pipework and wiring in my airing cupboard might amuse you.
I’ve a very large tank heated with 3 coils driven by wet solar panels, a wood burner and wood fuelled Rayburn. Also a solar boost feeding excess electricity from our PV šolar panels into the immersion heater and the wet solar pump and control unit on the opposite wall.
On the output side apart from the DHW take off, I’ve made a 4 zone manifold feeding a underfloor system with scrap off cuts of polypropylene pipes from work. This was originally used to dump excess hot water / heat but after insulating under the beams it produces a reasonable background heat and warm floors. It’s grown over the years as we have changed or added things so not laid out as I would have liked if we had planned for all the additions.
Our newer Rayburn has a larger wrap around boiler which produces more hot water so I’m now working on plans to install a plate heat exchanger to feed heat into our central heating circuit which will provide a more instant heat through the radiators.

I used to run the maintenance department of a very large plant nursery and we installed underfloor heating to heat the glasshouses. (That’s where the off cuts of PP pipe came from) As the nursery grew we ended up using a tanker load of gas oil every week in the winter which became a little expensive. We installed 3 MW wood burner and thermal store /buffer tank which saved us a fortune and we had RHI payments as a bonus.
As you say the tank stops the boiler cycling on and off which is even more important with solid fuel of course. Getting the tank through the lanes was quite a task as it was 3 Metres diameter plus the insulation and feet, we had to lift or tie back several trees. It was cut for transport as it was 30 metres long but even with a rear steer low loader some of the corners were tight.

You don't think all that is "overkill" for a caravan . JOKE.
Seriously, the wood supply I envy. I was buying Welsh Anthracite @ £320 tonne, towards end of last year over £500, now unavailable.

 

[Cornish Ian]

You don't think all that is "overkill" for a caravan . JOKE.
Seriously, the wood supply I envy. I was buying Welsh Anthracite @ £320 tonne, towards end of last year over £500, now unavailable.

Yes just a little I guess. Floor is beginning to sag and the tyres are bulging with the weight of the copper.
Good job our airing cupboard is a reasonable size but of course the newer Rayburn has side exit whereas the older one had a top exit so I needed some creative plumbing to clear some existing pipes.

Our wood supply came as bit of an accident really. I bought a strip of land that I was going to build a workshop on as I was working mobile or out of my double garage at the time. I did some work for the nursery and the owner made me an offer I couldn’t refuse so the workshop never got built. The strip of land and hedges were left to grow wood and 25 years later I’ve some decent trees there.
A former customer of mine recently gifted me with a lot of trees he had cut down so I’ve got about three years worth of oak, ash etc from him stacked in lengths in my field now.