Wood Stove

Without even looking I will say wood gas which is derived from the cellulose in wood which is released when the wood nears burning temperature, at this stage it condenses the cellulose in the wood fibres and releases it; its not a very efficient way of producing gas, but a method which has been around for centuries. They are currently looking at this for producing a form of bio-petrol from the cellulose of waste wood and rotting vegetable matter such as food, as they all contain hydrogen they can make a semi-synthetic petrol from it; or use a gas conversion kit on small petrol engines and run them straight off neat gas as its produced.

Many people in America are preparing to live off the grid and have bought large tracts of heavily wooded land, and this is one method they have of providing fuel, basically all the portable gas cylinders are being snaffled and the sale of hand operated low pressure gas pumps, and gas bladders have risen rapidly as they collect the gas in the bladders and use the hand pump to pump it at pressure into the gas bottles.

Thanks Assassin, for explaining it to me, I was curious to look, but it does look very messy,
dumping the ash out I would not have it in a house, have to be in a shed.

Actually its very clean as only the small inner tube has fire in it, the outer tube has the heat transferred to heat it up to temperature and the wood in the outer chamber is totally sealed from the fire tube, hence any wood in the outer sealed tube produces the gas and is not burned; what you end up with in the outer tube is charcoal as its hot enough to release the gas, but not quite hot enough to burn, and with a lack of oxygen it wouldn't burn anyway.

I looked at the video, and he was pulling leavers and it looked like he was dumping ash out.
I must have mistook what he was doing.

What he's doing is dangerous as he is actually burning the wood through lighting it and letting it smoulder, if a flare up occurs and it has any sort of flame the whole lot will simply blow up. He claims its efficient, its not, direct burning yields more gas but it also consumes around 50% of that gas to actually continue burning and it also needs oxygen to burn which also makes it explode.

This design has been superseded by the indirect method which is a small diameter fire tube which is inside a much larger tube, the larger tube is sealed and contains the wood to be gasified, the smaller combustion tube is open and contains the fire and this has no direct contact with the outer tube, and is therefore much safer because once it heats up it initially gives off steam. They normally fit an air lock similar to that fitted to a demijohn that winemakers use which lets out the steam as the wood dries, and then the gas once temperature is reached. It prevents air entering so an explosion cannot occur as the gasifier is not in contact with the fire and it contains only steam or gas depending at which stages it is along the gas producing process.

Many other designs are available, the pancake design is basically a wide diameter designed cylinder which is divided by a central plate which is usually in the ratio of 90% at the upper and 10% at the lower end and it has one or more chimneys passing from the lower 10% which is the fire pit, through the gasification unit which is the upper 90% and once again this is sealed and air locked. They simply throw embers into the lower 10% and stoke it with wood or other combustible material to raise the temperature of the upper 90% which also uses the heat of the chimney/chimneys passing through it to increase the heat to gasify the wood. This type is more popular with smaller pieces of wood, shavings, or sawdust and with commercial producers of wood gas as they are more efficient in their thermal transfer, particularly the multi-chimney types; they then connect the chimneys so they can use the heat for other purposes.

This is the problem with amateurs trying to work a principle rather than copying a commercial design, they risk life and limb and encourage others to copy what they have done by putting it on sites such as You Tube; others try it and there have already been a number of explosions, many injuries, and recorded deaths.

Thank you again Assassin.
I just happen to see it, it sounded too good to be true, but I can see it is possible done properly, but will not be giving it a go.
We have a gas cooker in the camper, and we will have our ozpig in the trailer, for outside cooking, Dilys was wondering if it is possible to run an electric oven/hob from leisure batteries and inverter helped by a solar panel, would you have any advice on that system PLEASE.

thank you

It is possible, but unrealistic unless you have a massive battery pack and the capabilities to charge it.

If we look at my boat for example, it has two large battery packs which are around 20,000 amps each and run through two massive invertors to provide back up power for many mains powered items and while they run everything fine as they were well designed, and the batteries for the two packs were free (I love free) it still needs a massive power income to keep the batteries charged, hence the reason most larger boats have an inbuilt diesel generator; mine is 28KW. These are in addition to the engine battery packs which are solely for the engines; and the power management system which will take either 24V DC or 240V AC from the engines, 240V from the generator, or shore power which can be 110 or 240V and very unstable.

Electric cookers are notoriously power hungry and inefficient and require high quantities of power for several hours, even the best are inefficient, so you would need to have at least twice this power in your batteries to power the cooker and overcome the inefficiencies in the conversion from battery DC to mains AC power, then the capability to charge them and a solar panel would do nothing unless you have a solar farm. Running a microwave is a better option as it consumes considerable power but only consumes it for a relatively short time in most applications, so is feasible. Running a microwave can be made more efficient through buying a 12 or 24 volt item and you don't suffer the huge losses through running through an invertor as most invertors are inefficient.

You would need a massive battery pack and suffer the weight penalty of such a pack, a system of charging it reasonably quickly which would mean a new high power alternator coupled to an electronic charging system for optimum charging capabilities, the cooker/hob itself, and have 240 volts in your vehicle at some point which can be a danger in itself. I would suggest avoiding this massive expense and buy a decent gas hob which will make the wife happy and still cost much less than such an inefficient electrical installation.

Looked up my battery specs. They are Absolyte GP.

Capacity 2014 A/H
Weight 89Kg each

Ten batteries in each pack = 20,140 A/H per battery pack, and 890 Kg per pack so not light as they both weigh 1780 Kg which may not be a lot of weight on a boat in which I buy fuel in Tonnes instead of litres or gallons, but it is still a significant amount to add.

Thank you again, as we all ready have a gas cooker, will stay with that and my be look for a 12v micro wave.
We have a split charge system to fit in and have bought a 70w solar panel, just need to get a leisure battery or 2.

If you use a 12 volt microwave then watch your batteries carefully and follow the manufacturers recommendations as many are designed for lorries which have masses of spare capacity in their battery bank as they have to run everything from lights to cookers with the engine switched off, go for the maximum capacity the manufacturer recommends, rather than the minimum. This may work out that twin battery set up's are the cost effective option for your leisure system instead of one large leisure battery.

As for the solar panel; basically they are very inefficient and will improve dramatically in the next decade, so don't be surprised if you don't yield a lot of power from it. You can possibly double this output with a few simple steps, park in an open space, don't fasten the panel to the vehicle permanently, move it around every hour so its continually facing the sun, and by taking a few simple steps you can get near its maximum output for much longer, or much more power output in poorer weather.

The plan will be 2 battery's, had not thought about moving the solar panel about in the day, some thing to look
into. thank you.