openspaceman

You drive twice as fast as I

You are right, unless you want the logs

OK I'll see if my brother will pick some up for me.

I was thinking a bit cheaper, 6", unknown hours (new ignition panel) but runs well, no stress control.

Understood Barrie. What are the price breaks on Aspen 2 collected from you? I don't think I'll use it regularly but intend to store machines with it.

I don't know but I think a firm in Rye does timber lanterns. I'll find a sketch to send

Also can you tow more than 750kg?

Them numbers are both the same?? I thought RON was resistance to detonation (Knock). Insignificant in a 2t engine as they have low CR ratios. I'm sure those JAP grass track engines were over 10:1 and needed methanol.

We used methanol because it was high octane, so I don't see why ethanol would lower the octane rating. What is the octane for aspen 4?

Right, I was sort of hoping that you were using smaller material, more oversized coppice. A long time ago Andy and I planed up some cleft chestnut to see how it dried and it seemed fine. The reason being of course that larger chestnut is prone to shake but worse spiral grain. The lantern light is a bit more complicated as it needs to sit on a box gutter between two existing porches, I don't think you ever came to my house? Another complication is I wish to extend the existing glazed area by 2.1 metres but for building regs this needs to be kept thermally separate. I was thinking of something more simple than a traditional timber frame, more on the lines of greenhouse glazing bars if the could stand the weight of double glazing.

Thanks Ian Using Lancer's figures there's a gross energy of 66500 kWh going in from the wood which I make 87% conversion but he's losing 5.4 tonne of water from the wood's moisture up the flue with woodchip as received at 30% so deducting this to give a net energy in the wood it could be 93% if his flue gas is similarly low. I'll have to do some calcs on your 105C exhaust and 100% excess air figure.

Great, my bosses may be economists but I doubt it

Looks a good use of chestnut, what size timber were they cut from? The copper nails look the business to me. What's your feeling about the idea of a conservatory with lantern light made from chestnut and double glazed panels?

It's another of those things in limbo, like network rail and the forestry commission isn't it? They don't know which master they serve and too many people dictating different policies.

Not quite so, Ed got the job but as a previous Labour appointee the home secretary would not approve the position and a Cameron man was given the job instead. The gardening leave is just to keep him out of the office till his notice expires.

I would doubt it, Have you split any? It may be that conditions in the fire are wrong or the draw is poor. You may simply need to have more surface area by splitting stuff much smaller.

Let's split some hairs: I'd like to know what the 90% figure refers to? Is it combustion efficiency, which would indicate incomplete combustion or is it conversion efficiency of the chemical energy in the wood to heat in the water leaving less that returning to the boiler? In which case I'd like to see flue gas temperature after the boiler fire tubes as well as O2 content of flue gas and rate of burning in kg as well as moisture content. I think anything over 80% would be remarkable in a wood boiler in the absence of a flue gas condenser. Even gas boilers at best will only achieve an extra 6% over LHV in condensing mode.

Is that measured over the weighbridge and through the heat meter? Have you checked the average moisture content? I could do with some empirical results as we never got good figures back once the boilers were commissioned. When I did any sampling during snagging visits the moisture content was always in excess of 30% wwb. I considered the chip suppliers to be overcharging and they would never agree to be paid on the heat meter apart from one golf club in Scotland where the local estate funded the installation. They effectively had a contract to supply heat but I only worked down south so was not involved.

Adiabatic flame temperatures are virtyually the same, around 2100C, wood is a bit behind at less than 1900C , of course these temperatures are never reached because of excess air, and wood needs more excess air. KG for KG 28 sec kerosene is the same energy as 35 sec gas oil, the difference in energy arises because oil is sold by litre and gas oil is more dense. So yes a litre of kerosene has to be worth less than a litre of gasoil

The Rolls Royce salesman school of thinking.

NB my graphs are on a wet basis, i.e. the moisture content is expressed as the percent of water in the whole green weight. I don't have a moisture meter but believe they are mostly designed for measuring joinery, which is generally expressed as the percentage of water compared with the oven dry weight. In my earlier post where I said 30C I meant 30% mc as measured by the meter So if such a meter indicates 30% mc Dry Weight Basis then it will be equivalent to 23% in my graphs. From what Cornish Wood Burner has said previously I would not expect such a meter to give good results above the fibre saturation point. See below, in round terms fibre saturation point is in the light blue region, pink is the sort area to aim for and black is dry enough to reabsorb moisture in ambient air. Burning wood in the dark blue region is likely to sizzle. A simple test is to try and suck through the end grain. wet basis dry basis 60.00% 150.00% 55.00% 122.22% 50.00% 100.00% 45.00% 81.82% 40.00% 66.67% 35.00% 53.85% 30.00% 42.86% 25.00% 33.33% 23.08% 30.00% 20.00% 25.00% 15.00% 17.65% 10.00% 11.11% 5.00% 5.26% 0.00% 0.00%

This depends on the size of the log, as the outside dries it becomes a poorer conductor, so the heat doesn't get to the inside to provide the energy needed to vaporise the moisture, what tends to happen is the cell water loses its viscosity as the log initially heats up, this then migrates rapidly through the grain and evaporates. The remaining "bound" water is associated with the actual cell structure by weak bonding forces and it is as this is vaporised that the log shrinks. This water is that at and below the fibre saturation point, about 25%mc. This is the water that takes time, and a bit more energy than the latent heat of vaporisation (AKA enthalpy of vaporisation about 0.75kwWh/kg) as the bonds have some energy requirement to break and this is reflected in the temperature being above the local boiling point. So if you look at my graphs on the other thread you will see the initial drying can be very rapid, then it tails off to an equilibrium of around 15% in ambient air if not rewetted. So the main answer is yes but I check weigh for the last hour or so to see if the log is still losing mass. Energetically there is not much loss with burning wood at 30C, the thing is it is a bit more difficult to burn it smokelessly (which represents an energy loss as well as polluting with particulates).

OK I understand, in your case the rayburn is on anyway so there is no extra cost in drying. It's interesting that once the log is dry it can be handled at 120C as the thermal conductivity is low as well as its specific heat, so the initial heat at the surface is conducted away from the skin faster than it is replenished from the log. Apparently the same is true if you dip your hand in liquid nitrogen but there's no way I'm trying that.

I have kept a new gomboy blade in stock for over 2 years since first finding about these files in a post on here, because I have kept the old one resharpened. I also bring all the discarded zubat blades home and sharpen them (I use the chain holder of the lidl grinder to hold them). I rehandle them with tape and hand them out for odd jobs . I am not able to get them as sharp as new but each side only takes about 10 minutes, as the worn ones come back with significant dullness I find I have to sharpen the front edge as well as the top ramp.

It's an experiment, not everyone needs to it just gives a more accurate result then measuring the changing resistance of the electrolyte as it becomes more concentrated. With an electric oven the cost is not too high as the losses are only water leaving, losses through the sides and the air bleed used to cool the fan bearing. Back in the late nineties I had a plot of electricity in against moisture loss and there was a very good correlation of electricity input being a standing loss+0,75kWh per kg of water loss for a given temperature.. I guess it costs me about the same as a pint of beer to satisfy my curiosity. I've run similar tests on the delonghi dehumidifier to see what it costs to condense a kg of water. My 80 mile commute to work and back is my most significant use of energy which I regret more.