Micro CoGen.

Quote from: Tom on April 15, 2011, 10:42:34 AM
Plausible scenario: Batteries under heavy charge 90% full and gassing. Engine shutdown due to false trip on engine safety controls. Batteries still gassing. Engine restart and a BACKFIRE into explosive mixture (I've seen my diesel fire and run backwards!). 911 call for unrecognizable body covered with acid and burned in a house fire. I'm a software engineer and design has to take into account what can go wrong, because eventually it does. A failing battery can also out gas prodigiously. 

Tom those scenario and the fact that valves can leak back from clearance or seating issues or sticking open. Restricted exhaust will also cause flashback into the intake.  Sure the odds do not lead to it being a common occurrance but when you are dealing with highly explosive gas mixtures you should have double redundancy at least for any easily forseeable events. I think it is irresponsible to promote and attemtp to justify such hare brained ideas. All the more irresponsible if you have qualifications that suggest you should know better. Even using the most strenuous application of all safety codes bad things happen. Once you start down the road of shortcutting safety factor and removing layers of reduncancy trouble is a certainty.  Enough of beating a dead horse though!

Wayne, you are a marvel with that calculator but in the meanwhile an awesome amount of the obvious seems to escape you. I wont bother checking to see if you are off an order of magnitude again in your windy calculations, but I will point out that there is a very big and easily explainable difference between the handling of explosive gases and the handling of them in a mixture with oxygen well within their explosive range. You entirely missed the part about static electricity. It can be caused by gas flow amongst other things. You may have noticed the phenomenon of lightning? Hmmm?

You seem intent on justifying as a potentially good practice, the idea of taking oxy/hydrogen gasses from battery charging and piping them into an internal combustion engine. You say there is nothing hot on the way. What, physically, stands between the combustion event and the intake runner?

Maybe you should do an in depth workup on the process and see if you can get it into the white papers section here on the forum; it certainly is a ground breaking approach to an age old problem. You should be able to arrive quite closely at the potential Btu reclaim but you may have to access the expertise of Lloyds of London  to calculate the risk / benefit analysis; engineers don't seem to be especially good at that and most especially so on their own creations.

Lest someone think you might be giving an engineers endorsement to this: Collecting the mixture of oxygen and hydrogen produced by battery charging is not a good idea! It might be if you could separately collect the components, then selectively combine small amounts at the point of combustion. Ignition by static electricity alone is enough of a certainty to make that a no brainer. 

Ventilation of charging batteries requires immediate dilution with large volumes of air to reduce the hydrogen / to oxygen ratio below the lower explosive limits.

Veggie, at this point you should make sure that cylinder protrusion is equal all around. This relates to cylinder deck being true with the bore for the liner. I had the same general amount of protrusion you had but it ranged from around .015 to something around.023 diagonally across the cylinder. I had to correct that first and then had even greater protrusion.

The option then would have been to either drop the recess in the cylinder casting, cut the lower surface of the top lip on the liner as Bob mentions, or remove metal from the top surface of the sleeve.

If you had faith that top lip thickness was standardized in view of future sleeve replacements, then it would be best to make the correction on the recess in the cylinder casting; that is a fairly cumbersome piece to chuck in a lathe though, so I  opted to machine the top of the sleeve and settled for .010" protrusion but that is at the high range of desirable. Probably more in the range Bob suggests, like .003 - .005" More protrusion gives more bite on the fire ring but less to the water sealing area.

"I don't mean to be argumentative, but some things just don't stand engineering scrutiny(sp?). <grin>"

Wayne, throw that calculator away; it is making you blind and deaf!

Raw data calculations are not a whole lot more worthy than astrological predictions if they ignore (or are ignorant of) field conditions that can often greatly modify the outcome. It is amazing how easy it is to get blindsided by some of them.

I see you have fallen in love with the notion of making joints in the ply sheeting; I think Jens gave you good advice there.

The figures are quite likely correct for the strengths of Resorcinol glue on wood under ideal conditions; theoretical values that do not take into account field condition effects of dimensional changes from moisture, heat, uneven and out of line forces that lead to spot loading and thus incremental failure. Bonding to one face layer does not engage nearly the potential tensile strength of the whole thickness. Progressive failure; divide and conquor!

A scarfe joint or a double sided scabbed joint would have mechanical advantages but  is way more complicated than the nature of the job warrants. Going to a larger tank has some apparent advantage in volume to perimeter ratio, but the strength in the whalers gives very quickly diminishing returns re. lateral deflection.

Also you cannot consider liquid in a tank to be a static load based on calculated pounds per sq. in. Vibration from traffic etc. is a very real and magnifying effect. I have been party to several shit outs of formed concrete. Someone apparently forgot about vibrating.

I dont feel the construction you have in mind would fail but it does have some potential negatives labor wise and there is some benefit in having your eggs divided between two baskets.

The ratio is not good, I know that. A monstrous amount of material has to be stripped aside to use for reclamation. The first areas developed only had 50 or so feet of cover over the tar soaked oil layer but that low hanging fruit is not the main course. The majority of the field will have to be steam extracted from underground. The tar is exactly like the roofing cement for patching and lap sealing rolled roofing but each barrel of it is soaked into a ton of sand and looks more like pot hole patching. Very abrasive on all the pumps and piping and high in sulphur and heavy metals. Light sweet crude it is not. There had been some preliminary work to do underground nuclear to liquify it and create a big drain cavity to collect it. That was cancelled due to agreements on underground nuclear testing.  I have flown locally over the workings a number of times and it sure is a scar on the landscape.

The only good part is there is lots of it and they sure don't have to worry about having blow outs like in the Gulf last summer. They do haul a lot of ethanol in to keep the inmates occupied.

It is very hard to drill holes that precisely and really the bolt should not be expected to maintain the lateral position as it has very small bearing area in itself. You are then dependent on shear forces only between the contact plates and the wood so the torque has to be maintained.  Unless you can be assured they are bang on you might as well slot the holes and perhaps use some kind of auxiliary adjustable dogs on each side or a slide plate with set screws. Epoxy bonding of the plate to the wood? Plates recessed?

In setting pumps on concrete it is common to have space around the top 10" or so on each anchor bolt so they can be moved a fair bit for fine tuning then grouted after the millwrights did their final shim shining. You might conceivably do the same with epoxy between bolts and wood. Yes it is a pain to have to lift the units entirely off to add / remove shims; common to have them slotted but you give up some bearing area.

I used to shoe horses; now that is the ultimate in alignment dynamics and keeping a chunk of metal firmly attached to a flexing and yielding medium! It is a challenge. I dont subscribe to it but some people used to heat the shoe and hold it on for a few seconds to burn down any high spots to get better bedding. That stinks of sloppy fitting, pun intended, 

It is a good idea to seal the wood well. Somewhat of a V shape to the motor mount is generally valuable as not all the forces are straight up and down but if you can keep things from starting to move you should be OK. The generator will be a little tamer.  I would expect your proposed setup to need a bit of fine tuning to the alignment as everything settles in. If that happens to be the case it makes things a bit easier if you put twenty thou. or so of shims under each of the mounting points as part of the initial alignment.

Don't pull too many negative G's 

It is not a question that the wood can take the load but it expands and contracts with temperature and humidity fluctuations. Where it is constrained against these forces (like being torqued down with steel bolts) permanent deformation gradually occurs after a number of cycles.

There is a reason for using steel shims to set motor and pump alignment instead of the much cheaper wooden wedges! You said it yourself; you are cheap.    I am quite frugal myself but I dont care to make fixes that dont stay fixed. Like I said, and I am sticking to that; I dont think wood makes good mounting medium for separate machines that require accurate and stable alignment.

Really the arguments about the relative pros and cons re. ethanol and other bio fuels is a bit like arguing the taking of vitamins while continuing to use tobacco. Energy is costly and the form we are most addicted to is a one time windfall that is about to quickly dwindle. North American energy consumption per capita is many times higher than what could reasonably be considered sustainable. Too much effort is going into desperate attempts to maintain consumerism and feed the wasteful system totally dependent on automotive travel. More local production of our needs close to the point of consumption may be a very necessary rethink. Labor intensive has been a dirty word but I think that will change as the real (unsubsidized) price of energy comes to bear.

Many equations are skewed by using arbitrary cost figures on components. Much of our food production under the current system actually uses 10 or more times fossil fuel input energy  than actual measured energy out; is that bad?

Bio fuels, ethanol and other concentrated energy forms will certainly be used in the future but we wont be burning them up to produce amusement or other non essential consumables. Certainly their production will have to be weighed against our food needs. Many things can only be enjoyed on a full stomach!

Quote from: mike90045 on March 29, 2011, 05:25:48 PM
XW6048 is fine with AC 1 (grid ) un connected, and AC 2 (generator) connected to  ....  a generator.


2" of snow, and my panels were at about 60% of normal !!  Then they warmed up, and the snow slid off - just gravel under them.

If you are in a heavy snowfall area and cold temperatures the snow doesn't slide off of a roof unless it is quite steeply pitched. We quite commonly have to shovel several times a winter even without panels on the roof. The south shore of Lake Ontario is famous for their winter snows.

Output drop from a given percentage snow cover will vary depending on panel type and connection layout. Partial shading can be a source of disappointment. 

Lots of newly minted installers the last few years with the all the incentive programs and they are sometimes not the best people to take advice from. As always, caveat emptor

A few folks who cannot shovel the snow entirely off their solar arrays are not too happy with their return on investment. A big rack of panels is necessary to support even a modest electricity dependance at 46 Deg. N.

Roof mount is cheaper and appears like a quick and easy place to park solar panels. Not so good if you are in a heavy snowfall area. Panels are much more efficient if you can tip them up to vertical to dump the snow off; otherwise near zero output. 

The calculations on total load bearing ability of the proposed 1/4" steel plates seems to make the assumption that they will not bend but rather distribute load evenly. Divide and conquer! 3/4" thick would be more likely. Also dynamic loading calculation is a different long term stability issue compared to static load bearing. Go have a look at how the rail shims obviously work into railroad ties. A diesel engine is a rather dynamic load to accurately affix to a wooden structure.

  In my opinion wood is not stable enough to maintain alignment for best coupling life. Any torsional flexing of the assembly also will effectively change relative height of shafts at the joint. Laminated is not as rigid as solid timber unless glued and pressed. Seasonal changes from moisture, different grain structure, temperature fluctuations, vibration etc., will continue to "work" on the load bearing areas of the wood.

  The life of the spider is greatly reduced by misalignment. Couplings should not be forced into doing the work of a pair of universal joints. Decking the whole base with a piece of 1/2 steel plate would help a lot.