openspaceman

Apart from the obvious mistakes in using the wrong units, pointed out in the comments, I think I see other bad logic , I'm off to be a log goblin now but if you want I can revert to it later. I thought I showed that it was modest and I believe coal comes from equally long distances. While the energy density of coal is over 1.5 times better the actual weights will be similar, which is why the the wood is densified into pellets first, plus once at the power station they can be crushed and blown in much as coal was.

Not to hand, I see it cited in a number of anti wood burning web pages but not the original evidence, I was told it in an online discussion with a combustion chemist from Colorado, Tom Reed. Their equilibrium moisture content year round is under 10%, he called it "Denver dry". I can explain the phenomenon: Take a cup of petrol and light it, as the petrol boils off the surface it burns with a smoky flame, this is a diffusion flame and the reason it has black smoke is that the carbon particles stripped from the hydrocarbon molecules don't immediately burn like the hydrogen does, they then have insufficient time to burn to CO2 before they exit the flame and are quenched in air. Take the same pool of petrol and entrain it through a jet like a carburettor and allow it to premix with the right amount of air before it is burned and you have a clean blue premixed flame as the petrol and air are intimately mixed. A wood natural draught wood flame tends to be diffuse rather than premixed What happens once the fire is lit is that the primary air reaching the bottom of the burning wood first causes the freshly formed char to burn. This generates a lot of heat and the heat in turn causes the remaining wood to pyrolyse. The offgas of CO2, CO from burnt char plus the pyrolysis products (and inevitable nitrogen) rise where they meet the flame and sufficient air to diffuse into the flame and consume all the fuel gases. Most of the time the stove is designed that the mixture of gases rising entrains the right amount of air to complete combustion plus enough excess air to ensure a fuel molecule meets an oxygen molecule. Pyrolysis above 330C is reckoned to be mildly exothermic, so once it starts in a log it can continue in a chain reaction. If the wood has some moisture then the chain reaction is slowed because the moisture absorbs heat as it is vaporised. If there is little moisture the pyrolysis chain reaction results in more heat in the log and increased rate of evolution of pyrolysis offgas. Thus the gases rising from the primary combustion increase and are more fuel rich. Hence the secondary air entrained is insufficient to burn the carbon out within the flame. Now this doesn’t happen in a pellet stove where the pellets are around 10% mc wwb because the pellets are trickled into the burn pot at the same rate as sufficient air is supplied by a fan, so the pellets char, pyrolyse and burn at a consistent rate.

If you go to https://www.check-mot.service.gov.uk/ you can register for a reminder, I over ran my first fiesta mot by 8 months and about 10000 miles and never got pulled.

Thanks for the correction Graham I'll rework it below and take your point about being well stacked, the other point is the bulk density goes down as the logs are split down smaller. 1.7m^3 solid will weigh about 1.8 tonnes green beech, seasoned to 25% it will weigh just short of 1.25 tonnes

I would guess about 50% of that is air space so 1.2m^3 of solid wood. Weight would depend on basic density of the species, gum over here is eucalyptus and heavy. Beech 1.2m^3 solid green wood weighs slightly more that 1.2tonnes and contains 45% water. seasoned to 25% (the easy bit) and it will weigh about 900kg

I have two, one is a pellet stove which is one of the first batch we imported from US in around 2000, seldom used and an old 1980s jotul 602 which is getting past it's use by date, It is a basic metal box and doesn't compare with a modern offering for cleanliness, soon I'll have to bite the bullet and get a modern one that meets the new standards. I have recently constructed a glazed log store which I hope will increase seasoning rate and keep logs dry in the winter, having previously relied on an outdoor stack for 39 years.

For various values for dry. There is some evidence that bone dry/oven dry wood burned in a natural draught burner has increased particulate emissions. Not likely in UK or most other places where the equilibrium moisture content settles out above about 10% mc wwb (~17% in a dry shed in winter by me)

Yes, the yellow may be because of bright sunlight but what makes you prefer that over dawn redwood, I would need to see whether the fronds were opposite or alternate.

I had a stab at that and that we're discussing burning pellets, the fact that they are pellets pretty much guarantees they are around 10% mc wwb I wasn't defending the trade just wondering where those articles got their idea that the carbon footprint was worse than coal. Of course the atmosphere doesn't distinguish whether the increased CO2 comes from gas, oil, coal or biomass. The hope is that if the biomass is harvested sustainably any CO2 produced in one year will be mopped up by the next, which is not the case for fossil fuels.

I didn't notice any sensible workings From a quick search it looks like large ocean shipping has an energy cost of about 0.11MJ(MegaJoules) per tonne per kilometre, What I don't know is whether this accounts for an empty return leg. A tonne of wood pellets has an energy content of around 18600MJ and I'll neglect the ~2.5% energy cost to make them. Shipping from Florida to England is about 7000km so each tonne will have a fuel energy cost of 770MJ to ship it. This is about 4.14% of the energy in the delivered pellets. It does of course neglect the fact that the fuel oil used in the ships' engines has more energy utility than the heat energy in the pellets. Financially it's attractive because we have subsidies to burn wood, the americans have no particular advantage to burn the wood because there are no renewable incentives plus their gas price is much lower than ours since fracking was brought online.

The fronds look mimosa like

No. Were you always cantankerous or did it come with age?? It's an interesting charity making gizmos for remotely doing things like door opening and his source of servos etc. comes from returns of remote control toys, like battle tanks. The importers decided it wasn't worth arguing or attempting repairs as the portion of failures was small so he gets loads for free. http://www.remap.org.uk/

Firstly we don't know what plastic bit in the pump failed and there do appear to be parts available. I haven't any experience of 3D printing but a friend does and he regularly produces bits for a charity making bits for disabled people. As I understand it you first make a 3D technical drawing of the part in a program like autocad, from this a file is generated and sent to the printer which builds up the part in layers of hot plastic. Ideally a manufacturer would hold the technical drawings and either sell the print file or print the part as a one off if it was no longer stocked.

The gasifying ones we fitted by Kunzel and Kob did but they were serious money. I just heat the space with wood and gas or electricity for hot water.

FC used to publish figures for standard minutes it took to fell and sned a tree which allowed for size and number of whorls. There being 480 minutes to a working day and allowance made for rest breaks, fuelling, sharpening etc. This was then used to set a piece rate for the job.

I wonder if this sort of thing could be 3d printed??

? just like usenet I suppose you mention boiler stoves because of the way they generally cool the firebox rather than take their heat well after the flame? I'm not really interested in a boiler but I intend to replace my Jotul 603 with something reaching the new standard but a bit lost where to start on choosing

So I can connect to my side of the stopcock without asking?

What are the rules for this? I know it needs to be 750mm below ground but if I ask for a new connection at the road they'll want money and a meter. Currently still on 3/4" galvanised iron but it is probably quite furred/rusted up.

My memory isn't that good but it was significant, rails were worth a premium over 8ft tree stakes then 5'6" stakes, these we were paid by the piece. That was first thinnings or respacing regen and there was a blip in the price-size curve then which meant second thinnings were worth less as they were too big for PSR and too small for getting many small bars from them, so much tended to go for newsprint pulp. When subbing I got caught out by the harvesting company because the assortment meant the price overall was bad. I think we got £6/tonne cut and extract for 1 metre pulp and about £8 for bars down to 5" under bark. At the time I both subbed for a harvesting company and bought standing. I seldom produced pulp on my own timber when producing PSR as I'd prefer to waste small bends in order to maximise the various post stake and rails. As I said earlier the harvesting company, who also owned the stake plant at the time,"cooked" the figures so it appeared to the land owner that all produce including pulp showed a return when in fact the harvesting and haulage of pulp probably exceeded the delivered price, so they paid themselves less for the PSR to subsidise losses on pulp. Consider also at that time as well as treating all the stumps with urea we had to remove all produce over 2" and cut tops to less than 6ft so they would dry out before becoming hosts to the various pine beetles. As I said I look back on the period as being enjoyable but financially disastrous. I do pass a plantation by aspen Bob's yard where we did the first thinning and it has just been machine harvested, its a good looking pine plantation now. This would have been the period 1978-83

I doubt we ever got up to that, mind we were in scots pine mostly and the trees were 0.05m3 so if you didn't have a good assortment of PSR material paid by the piece and just cut pulp the pay was poorer. PSR made the forwarding a challenge. Prior to that I pulled tree lengths out as it seemed to result in a better selection and I'd be making 50 trips a day over an average 500 metre distance. Last week I visited the lad who was working for the opposition respacing natural regen from the period when I'd moved on to hardwood, about 83 I'd guess, he was very prolific with a saw. Now he owns and drives a timberjack forwarder with intelligent boom control, self levelling and rotating cab and shifts 150 tonne a day (mind its 5metre douglas sawlogs off a clearfell). We've come a long way but I doubt we'll produce crops like this with the current establishment and thinning regime.

I'd like to see the workings for that

I was wary of suggesting rope in this case because of the need to to and fro the piston, increasing the risk of a bit of rope working its way into a port. I normally use rope and have never owned a piston stop.

Be aware if the clutch is binding on the drum it won't pull apart when you take the four screws out. Try locking the cylinder and then carefully joggling the blade back and fore to free it off prior to dismantling.

Rusty clutch?