gas engine/evolution?

[mobile_bob]

i have diy books from the 70's, 80's, 90's and some newer

thinking back to the early 70s when going offgrid was the cool thing to do, there was lots of books written
on how to produce power for your offgrid cabin/tent/home.  much was done with an old lawnmower engine, a 10si delco
some old car batteries from the junkyard, and 1156 bulbs from the junkyard (with their requisite sockets).  you had some independence, some power storage, some light.  you could track down and rebuild an old wincharger, or maybe an old delco light plant, and if you had the money you could find a used kohler generator out of a motor home (tall cotton then), there were motor/generators but they were very inefficient.

by the 80's there were some solar panels coming out, bloody expensive, some inverters also expensive, prone to failures, and of course square wave or modified square wave.  folks learned about golf cart batteries and things were better

by the 90's there were better/larger and less expensive inverters, and the market had  pure sine wave if you could afford it, modified sine wave came down in price as well.  solar panels were coming down in price as well.  the listeroids and changfa's started to come onto the scene as did the ST heads, There were several controller, charge controllers, all sorts of other cool things used in the marine industry that found a place in offgrid,

in my opinion the 90's to about 2006 was the golden age of offgrid power production in many ways,  prices came down, and the average guy/gal could actually put together a system that could provide power enough to live a relative modern lifestyle within limits of course.

then about 2006 the EPA banned the import of the listeroid, changfa and their variants for import, and it would seem that put a stop or a slowdown on offgrid development, particularly among those that frequent this sort of forum.

thinking back it seems this game is cyclic,  the 70's with oil embargo, recession and a lot of younger folks wanting to drop out and move out into the sticks, really was the renaissance of the diy offgrid power production. then it kind of died down till somewhere in the 90's, then died down again after about 2006 or so, and has been somewhat down since then.

i am thinking that it is probably about time for the pendulum to swing back as evidenced by the civil strife we seem to be witnessing, the global economy being somewhat questionable by most any reasonable standard, and the fact that the younger folks and older folks are driving this tiny house movement pretty much all over the civilized world (the uncivilized world has been living tiny for eons).

taking stock of what techologies exist, or has changed, or basically what is there to work with?

1. solar panel prices have fallen dramatically, although i am not sure if they are still around a buck a watt or not, they certainly are relatively speaking pretty low in cost, and reliability is probably as good or better than ever.

2. with the lithium ion battery technology being so darned efficient, and coming down in price, it seems that this is a quantum leap from the car batteries used in the 70's and a significant improvement over golf cart and other deep cycle lead batteries

3. i suspect that the inverters are as good as ever, probably more reliable, lower in cost per watt than they have ever been.

4. lot of surplus odds and ends available and useful?

5. all manner of microcontroller stuff and lots of folks able to work out all kinds of control system, only dreamed of not more than a generation ago, and cheap too/

so whats left?  no prime mover?  no diesels?

what i am now kicking around is this, (spitballing so to speak)

if we accept that there "is" a need for a prime mover, especially for cogeneration
then do we really need a diesel engine?

is it possible that a gasoline engine (water cooled) might be nearly as efficient?  maybe if used in a very tightly controlled and specific manner?

i am of the thinking that maybe, just maybe something like for instance a salvage 1.1 or 1.3 liter honda hybrid car engine
direct coupled to perhaps a 15kwatt st head (or equivalent 4 pole head) and used to do both 120/240 volt power generation and also bulk charging of a bank of lithium ion batteries and an inverter system.

perhaps in an offgrid system, where heavy loads could be scheduled to be supplied for short period of time, periodically through the day, or perhaps and hour in the morning and an hour in the evening might be enough to do the heavy lifting, provide enough domestic hot water, and heat when needed, and also run for short runs during the day (cyclic) driving an A/C compressor (or 2 or more for zone cooling) with purpose built tstats and control systems.

not sure, but i would not be surprised to find that the overall efficient in cogen mode could be quite high.

the little 1.1 or 1.3liter engine's run relatively quite, with extended oil capacity and a bypass filter, synthetic lube oil, well filtered air and fuel, the longevity of the little motor might be quite surprising.  the little engines seem to be readily available at relatively cheap prices,  less than 500 bucks with freight, however i don't know how complete they come, but suspect they can be had as complete as one would want to pay for.

the reason i am kicking this around, is i just drove back a 3.6liter VVT DI buick enclave (about 5k lb car/suv) and at 70mph it sits right at 1800rpm and seems to have ample power to run stable, run the A/C and get along just fine... they are known to make 200k+ miles with decent service, (probably a lot longer with the sort of service added oil capacity, and maintenance it would get if it were skid mounted to where you could get to it, and not under the hood of a car that is driven over a wide range of conditions and rpms)

from what i have read the lithium ion battery technology can accept a high rate of charge which would enable the use of more of the available power of a 1.1 or 1.3 liter engine.

then there is the possibility of conversion to propane or natural gas?  lower output of course, but better fuel storage and better control over fuel price, and infinitely longer storage life over gasoline.

i know i have been complaining about local politics and having little to no time these days, however having spent about 4 hours with the wife going after the buick we had time to chat in depth and came to the conclusion that i have done all i can for this community, and it is high time i got back to things that i get enjoyment from.

so maybe i start thinking about this hypothesis and see if i can move it from idea to something with teeth in it?

one thing for sure is this, living in town, running a diesel (changfa) is problematic (noise and vibration), and being able to work with a little 4 cylinder gas engine would alleviate those concerns, and i have ready access to natural gas as well.

interesting to think about anyway?

thoughts?

bob g

[playdiesel]

If I were to head down that path with a gasoline engine I would search around for one of the 3 cylinder Kubotas, no computer needed to run it. Neighbor had one in a G1800 lawn tractor that is identical to my G1900 other than mine being a diesel, about 19 HP as I remember.

[Hugh Conway]

@ Bob
I'm one of those off-griders,  Cut the wires in 2112, just about the end of the Listeroid phase. I do run a 6/1 with a 3Kw Utterpower PMG, and big lead acid batteries with a modest array of solar panels.
No need for anything more, and we run a fridge, 2 freezers, 3/4 HP deep well pump, washing machine, and a shop with table, band saws, planer, and the usual power tools.
Fuel cost is about $300 per annum. We don't feel like we are missing out on anything, even with this seemingly small  generating capacity. I never let the batteries get below 85% and run the genny just about daily for 2 hours in the late autumn/winter/early spring, maybe 250 hours a year........Pacific coast Canada......it's pretty cloudy here then.
We are fortunate up here in that there's no prohibition on the Listeroids or Changfa types. There are still a few dealers who can supply complete engines and parts. It's a pretty simple system, a couple of crescent wrenches and an assortment of hammers will keep it all going nicely.
One thing about the gas engines is that the fuel degrades so quickly. We have a couple of 400 litre diesel tanks, one for the genny, and one for our Japanese import truck  (another thing that is legal here). That much fuel lasts me a long time without having to leave the island to get more.

My thinking is:
Get outta town, sooner = better

Cheers
Hugh

[glort]

is it possible that a gasoline engine (water cooled) might be nearly as efficient?  maybe if used in a very tightly controlled and specific manner?

I have been helping  my fathers neighbour with a solar setup on his house and have been looking at this.
You mention a $1 a watt for solar. I am buying used 250W panels Regularly  for $15-20 ea.  I know they are not that cheap everywhere ( and I do wheel and deal them cheap) but the thing is with adequate panels, you do not need a lot of hours on a generator. I also think the trend has gone away from large battery storage to more panels.

That said, I made a new generation record yesterday of 87.1 Kwh. Today was terrible weather, I reckon I would probably not have made 10. Balanced with ones battery bank and electrical demand,
Even accounting for bad weather ( depending where one lives) The hours on a generator may be very low anyway.  A mate that is a car salesman is always telling me about how people constantly want Diesels because they are cheaper to run. They are also nearly $12K more in what he sells.  He said so often he looks at the KM on the car they want to trade in and the age, shows the potential buyer than in fact with the price / range different they are going to be thousands behind the 8 ball, shows the maintence cost and the probably trade in value and the diesels make no sense at all.  He sells a shipload more of the petrols than anything else and does it easy because people end up spending less than they expected.

I thing the same could apply here.
I have a LOT of small China 8 Hp engines and a good few 18 Hps as well.  These things are cheap as Chips and give very good service. For battery charging they are all one might need.  If they run all day on occasion, who cares? They are cheap to replace, use little enough fuel not to be a concern and are now coming out in Fuel injected models that are even more economical.
Not sure what the fuel price in the US is but it's really just the margin you have to look at as one would spend money on diesel anyway.  While probably a bit more economical, Diesel also averages about .10C a litre more exy here.

Also, I don't know the price of used car engines in the states but I would also suggest capacity isn't that big of a deal. If the small engines are harder or more exy, I don't think there would be much difference in a 1.5 1.8L engine fuel consumption. This ISN"T a car the thing will be dragging round. The load will be the deciding factor and I'd suggest a 1.3 and a 1.8 engine are going to have close as dammit consumption on the same load anyway. You will need a Computer, harness and a complete engine with accessories. You will also need the fuel pump and even the ignition switch if it is new enough to be all tied in together on the computer. You will also need the exhaust to back behind the cat as there are likley to be fore and Aft O2 sensors the engine will want to see as well. Probably also want the airbox and the map sensor that may be built in.

The better way to go might be to just buy a running wreck.


The Co generation aspect of a water cooled engine is an important one. I was going to do an AC setup myself. The average car AC does roughly the same output as a mid size home split so they are viable.  Not much to them, just have to connect the evaporator sensor so the Compressor shuts off before the core freezes up or you hit the temp you want. Getting these components would be another reason to buy a complete Vehicle even if pulling the dash out to get to all this stuff is a pain.


My own battery choice for stand alone would still be lead acid. Here it's still much cheaper and forklift packs are very economical and companies are warranting them long term for solar use. They also have decent inherent value at end of life which also reduces their cost.  The charge currents may be an issue but then you can hammer pretty decent currents back into those forklift batteries as well.

[playdiesel]

As said the Ideal system depends on where a person lives. Where I am it would take a lot of panels and storage capacity to depend on solar for the bulk of energy needs, its been tried. We can go for a week and never see the sun. Also the mechanically illiterate ought to stay with the grid,, seen that fail too. With internal combustion as the backup alternate fuels can really tip the scales toward diesel. I have a supply of used motor oil that is virtually endless. My favored route would be grid tie but holding me back is the cost of it not on my end but what the power company requires,,, its a LOT of money and if doesn't pay back when a person is all in why do it? 

[BruceM]

I'm off grid in central eastern AZ at 5600ft.  Sun is not an issue here, PV is king, but there are plenty of old wind generators out there too, from back when PV was spendy and wind power during winter storms was mighty handy.

I"ve recently looked at converting my 120VDC to lithium NCR20700B cells as my battery bank will need replacing within the next year.  My current (Group 29) wet marine battery bank is 110ah each at 120VDC (10 in series) and costs $900, lasts 4.5-5 years. My DOD is typically 25% in winter, 15% in summer.  A comparable system should have 35AH (minimum usable) at 120VDC nominal.

The NCR20700B cells are rated 4AH but have only 500 cycles of that.  For longer life, you must reduce both high and low ends, so the effective capacity might be 2.5AH.  So being cheap at 14 cells in parallel to barely make 35AH, by 36 cells in series  is $2646. plus shipping at a discounted $5.25 per cell.  This might last 10-12 years, but even at that is still not cost competitive, yet.  (Not counting the new BMS development and construction.) Maybe by my next battery set in another 5 years...  (I've been saying that for 15 years so far.)

I have no use for a big, high current battery charger, in fact, since adding 1500W of PV to my 875W array, I have no need for a charger at all; even on dark winter days I get enough charging, since I avoid all my big loads unless it's sunny or only partially cloudy, in which case the batteries are just a short term buffer.

I do now think that perhaps a well designed, economical, open source PV rack/tracker design would be nice to extend my early morning and late in the day big loads in summer.  The vertical tilt could be manually adjusted monthly.  My ground racks have seasonal tilt only, so mornings and late day are lost in summer  We have very high winds here in spring, thus I have been reluctant to do it.  My ground racks were homebrew from steel square tube and angle and only cost a couple hundred each.  Given the cost and problems here with tracker racks, they mostly have been abandoned by all the PV/off grid contractors and suppliers.  Motors, bushings, bearings etc., all get eaten by the endless AZ dust, and the electronics don't fair that well either.  I may just install another 1500W array mounted on a vertical rack with a pivot pole mount in the middle and a drop bar into concrete on each end to hold it securely.  That could be manually pointed to sunrise or sunset to augment my existing arrays.

[playdiesel]

Bruce, I was just watching a show on HGTV where an off grid home added tracking to thier array. I can't quote the figure but I was astonished at how much capacity it added to the same amount of panels. It was however it bit spendy to purchase and install.

[glort]

Bruce, I was just watching a show on HGTV where an off grid home added tracking to thier array. I can't quote the figure but I was astonished at how much capacity it added to the same amount of panels. It was however it bit spendy to purchase and install.

When I set up my solar, I was of the belief that it had to be set up on racking to  be able to ajust the tilt if not actual Track. For a couple of months I debated the best/ cheapest way to do it but was VERY cautious due to the high winds we get here which will start next month.  My shed roof is pretty much flat so after a bit I came across a solar calculator and thought what If I just put them up on the roof till I figure this out and  make something in the mean time?
As it turned out the Roof was pretty much at the ideal angle  for 3 months and a real good angle a couple of months aside that.

I then found a tracking calculator and was surprised at how LITTLE difference it would make in the grand scheme of things here.
The other thing is the cost of a tracker and how much you can put on them. Helped develop my solar rule of efficiency,:  INEFFICIENT  is better and cheaper.
Time you spend money on a tracker, one is far better off spending the equivalent sum on panels.  You'll get more power in good light and you will sure as heck get more power in the not so great weather.  Tracker is useless in cloud, does nothing. Having more square inches of cell will however make a big difference when you need it most.
Most trackers are Limited to 4 panels, maybe 6 But when you get up to something that size you are talking substantial $$ which would buy a LOT more panels and Just give so much better output operating less efficiently than they would trying to squeeze every watt out the things.

Panels are so cheap now I cannot myself see the sense in trying to improve the efficiency unless it is with some sort of Simple tilt adjustment on a ground mount that adds no cost to the setup.  Maybe one could add a wheel to the end of the array and orientate it morning and afternoon or some thing but really, who wants to be stuffing round with that all the time?  Throw a couple of extra panels onto the setup and be happy and again, get more power when you really need it in the crappy weather. Moving decently large arrays around of say 4 Kw+  would start to be a challenge as well unless very well set up.

Tilt may be worthwhile. Certainly 2 stage, winter and summer but one could do 4 spots as well  including flat for summer and crappy days if you were that enthusiastic. I am fortunate in that my North roof arrays are pretty much summer and winter tilted by Default. I just put another 6.2 KW on the house that are winter tilted and they really gave things a shot in the arm. I can on sunny days now generate an excess in winter which is great. The shed array which is about 9 Kw is more summer tilted and also good in bad weather.  The Back couple of arrays on the house of around 7 and 8 Kw atm are west ( afternoon) orientated and and at a winter tilt which give great generation  pretty much till almost sunset.  Take a bit to get going in winter till the sun gets high enough but now the north array is up I still make decent power till they kick in. 

Here in Oz the off gridders are getting away from north facing arrays and going to split east west.  Obviously it's not the peak power they are chasing for battery charging but rather the most steady and longest hours. Some are finding really good results from having the panels at a 60o tilt facing east/ west split.  Again not the maximum power but the most even over the course of the day.


The thing with using Diesel engines has always been fuel and a lot over the years have been using alternative fuels to have a lower or Nil Fuel Bill.
That said, I have already come to the conclusion that using a petrol Motor may not be a worse proposition economically.
Small petrol engines are FAR easier to come across, FAR cheaper to buy, miles cheaper on parts ( WTF are diesel Parts so dear when they are really no different to SI engines? ) and if you amortize  those costs over the increased running costs ( if any) over the minimal hours a lot of these things might need to run, one maybe no worse off. Of course if one is going to log big hours, then rebuild replacement costs have to be factored in as well.

There are plentiful available Gas carbs now even for small aircooled SI engines.  People have also converted Diesels to SI for petrol and gas and with the various controllers available now, is not that hard at all.  Bottled gas here now is in most cases more exy for the same energy content as Petrol. Used to be Cheap, Not any more.

As for storing Fuel, I think the main trick is keep it airtight.  Oxygen is what degrades most fuels and if you keep that out there is chemical reaction hat takes place.  Having run Veg oil for 20 years, that's pretty much 2nd nature anyway as veg does not store well with air exposure either. I have a Drum up the back I am using atm which I put away 10 years ago. Still good as when I put it in there far as I can tell.

I think with any engine, the packaging is important.  Some are just a lot easier to set up in an enclosure for sound. Others like Listers pretty much require a Room or a shed.
If one looks at the space they have and how they want to package it, that can be a factor. If you can build a soundproof shed, then diesels are not a problem.  Rubber mouth them, Put on a  couple of car/ truck Mufflers, another on the intake, baffled air inlet and  outlet for the shed and that's it. If one has to just enclose the engine itself, things are different.

Fuel injected engines do need to be set up carefully in order to run. There are a lot of things they look for so one needs a whole lot more than just the engine  to make them work.   

[mobile_bob]

it has been a number of years so don't dunn me if i get it wrong
and based on this topic being one of exploration of a thought.

i will expand a bit on the thinking

1. solar has become very attractive with its more reasonable cost, much lower than even a few years ago.

2. battery technologies have shown some interesting and applicable usage over the last decade or so, and who knows
if the solid state battery technology such as tesla's million mile battery will become a reality sooner than later.

3. the use an internal combustion engine, beit gasoline or diesel, used in cogen applications makes sense "if" one has a ready use for the excess heat harvested.

4. any internal combustion engine is really a much better furnace than it is as a producer of rotary torque, a larger percentage of the btu's from burning the fuel of choice is converted to heat than is ever converted into rotary force used to turn a generator.

so given these examples

in the summer time, at least in my part of the world, there is little need for heat save for domestic hot water in the summer, so the run time of a power generation unit would be very low on an average day, "if" one were to be using sufficient PV solar panels.

in the winter, again in my area, there is still fairly good solar potential, however the need for space heating is certainly higher and as such the run time of a cogenerator is high enough to make good use of the heat generated.

as for batteries in any time of year, it makes sense to me to size the bank such that the cycling of the bank is minimized in as much as is affordable.

the last consideration is one of either using a SI (gas engine) or CI (diesel engine) or a hybrid (diesel converted to using vaporized gas, such as propane of nat gas).
given any of these engines are much better viewed as furnaces, does it really matter whether the efficiency is 32% (typical of a diesel engine) or 25% (typical of a gas engine)?  i think not.

reason being and assuming that either example is setup to run cleanly (low emissions) then whatever we don't get out of the crankshaft in torque we get out of the waste heat streams (water and exhaust) that we setup to harvest the heat from.

technically the gas engine has more heat per unit available to harvest than does the diesel engine, and conversely the diesel has more torque (mechanical force) available to harvest than does the gas engine.

therefore i am not sure that there is a huge advantage to either engine type when it comes to a fully implemented cogeneration scheme.  design and sizing properly is likely far more important than whatever the difference in brake fuel consumption numbers are, the better the design, sizing, and implementation, the higher the overall efficiency.

now i have not considered in this discussion the possible longevity edge going to the diesel engine, typically they last longer than gas engines, however there are example of gas engines that have excellent long life history's such as the dodge slant 6 (no i am not suggesting a slant 6 for cogen, however it might work well for some applications).

my example of the honda 1.1 or 1.3 was only because it was the first one to pop up on ebay as widely available, cheap as a used engine from salvage yards, and made by a company known for well engineered, designed and built engine's that on a whole seem to last forever (not to say that the 1.1 and 1.3 fit these categories, i don't know anything about this engine example).

whatever example used, beit honda, ford, volvo or whatever the recommendation that it might well be best to buy the whole car so that one would have all the requisite stuff to make it run, such as the computer, all sensors, wiring harnesses etc.

finally a digression ( i used to be known for that)

bank around 2001 or so, i bought an 86 nissan sentra at a tow auction for iirc 15bucks or so, it had a little 1. something liter engine, iirc a simple computer, i think a puter controlled carb, and the engine looked to have been very well maintained.  i pulled the engine, radiator and every stitch of wire etc out of the car, had a hulk hauler pick up the rest.

my plan at that time, given i was in the process of exiting a 22 year most difficult marriage, was to build myself a small (ok tiny house) outside of my home town in kansas.  i had recently bought a 54acre parcel that looked to suit my needs and some.  the parcel had access to power, but being a diy sort of guy and given my study of offgrid power production going back to the early 70's i thought this would be the perfect time to actually be part of the system as a whole.  by system i don't mean it in the classic sense, but rather part of the system that i lived in (house, power generation, storage, food production etc, and not part of the system where i continue to work my ass off just to make more money, where i get taxed more, thinking i have to make more, the whole "stop the world i want off" thinking seemed most interesting)

what i planned was to mount the little nissan engine in an enclosure, that was cube shaped, about 4 ft on each side and about bench top high.  within this cube would be the engine, the radiator (to dump heat into the shop in winter) a bypass to take water heat to the tiny house in winter or to another radiator outside in summer (for those limited run times in summer where i had little need for space heat) an exchanger to heat domestic hot water.  i had planned on a generator to make 120/240 but thinking back i think it was to be an induction generator as i had a 20hp 3phase 1740rpm motor.

the power cube would also have an A/C compressor (at the time a York as i had one on hand and used them for years) using r22 which add's about 50% more cooling capacity over using r12 (which r12 was getting to be very hard to get anyway) and a couple of 110-555jho alternators.  there was also to be a pto which would allow for driving various thing on the cube/benchtop, things like a bench grinder, a drill press, etc.  (things that run for short periods of time as needed)

my plan was to set it up in my little shop, where i could get around all sides, put panels on it to deaden the sounds, put the exhaust up through the center and out the roof, all other connections under the floor.

my thinking at the time was only to run for maybe 30min twice a day, have it set on an autostart timer to 30 min before i got up each morning (so i have hot water for a shower) and the same in the evening so when i got home i could have a hot shower, and enough to wash dishes or do a load of laundry.

other run times would be on a control scheme, set the thermostat and when the place cooled down, then startup and warm things up, and while doing so, put some charge in the battery bank, and drive the purpose built fridge and freezer.
i had even considered building my fridge on top of the cube, and also use absorption process to use the excess heat to drive the cooling needed.

then in early '06 i got my first changfa, and somehow things took another direction. looking back i think being a diesel mechanic for so many years it just seemed like a natural progression, however now i am not totally convinced it was the best road to take, especially given the difficulty associated with the EPA.

lastly i think this path might well be considered given the difficulty procuring small diesel engines, for use in cogeneration, an given the readily available small watercooled engine's taken from wrecked cars. one thing is for sure, cars will be around for a very long time, and where there are cars there will be wrecks.  so maybe these engines should be considered at least until such time that the lawmakers make it illegal to sell a wrecked car or its parts, mandating the things be crushed and fully recycled.

we get to that day, and i give up.

bob g

[glort]

in the summer time, at least in my part of the world, there is little need for heat save for domestic hot water in the summer, so the run time of a power generation unit would be very low on an average day, "if" one were to be using sufficient PV solar panels.

I think one would need to work out a basic design and Budget.
Do you want a generator as back up for solar or solar as a back up for the generator in topping batteries off?

I think that's the first thing to decide.  From there you can have an idea of what the generator needs to be capeable of.

If you can put sufficent solar up to take care of your needs the majority of the time, then the generator can be a small cheap  8 HP aircooled  even which will probably give a good many years of service and you can afford to buy 3-4 at once for backups.

If you do want the heat then a watercooled would be better. That said, would you be better to put a fire place in your tiny house? If don't want to, they you could ( depending where you are) heat it with a Couple of KW from a fan heater.  I have been playing the last couple of days here with running 4 Fan heaters on low power ( about 1 KW)  and they do a pretty good job of keeping the chill off nicely.  As the home you are talking about is smaller than my kitchen, then I would think your heating requirement is very low.

Another potential for heating is now the small Cheap Diesel heaters that are available. They do up to 5 KW and are designed for RV 's and campers so also turn down well and have thermostatic control etc.  People are testing them running 50% Veg oil or Bio and they will work fine on that halving the fuel cost.  Here if you work out the heat output for the price. they are far cheaper than buying grid power even on 100% Bought diesel.  Run them on home made Bio which is about 20% of diesel cost and one is laughing.

Other option is a small Reverse cycle AC. For the house size described a small Unit that may barely run 1.5 Kw would do the job as the new ones are very efficient. I am looking at putting another 18 Kw Multi head in my place and  with 18 KW Cooling and 14 Kw heating, the electrically draw single phase is under 5 Kw for the whole thing.  I had no idea they were that efficient myself.
While that may sound a lot, one has to compare it to the solar I generate.  That is a big arse AC yet it would be easy covered by even a " Normal" 6.6Kw  system here.  Not going to pull 5 Kw continuous, will throttle to keep the temp set so unless in extreme weather the solar would keep up.
A small split would be all you need and give all year round comfort with a modest power draw.

as for batteries in any time of year, it makes sense to me to size the bank such that the cycling of the bank is minimized in as much as is affordable.

Again, would not be hard with solar to achieve that.  I can pretty much run everything in the house on a sunny day even in winter and still be exporting from the solar.
When it is overcast, solar is near useless so your engine would be required. How many days a year that would be is the question.
A lot of the offgridders are going that way now. Have enough solar to do what you want and still be charging the batteries.

technically the gas engine has more heat per unit available to harvest than does the diesel engine, and conversely the diesel has more torque (mechanical force) available to harvest than does the gas engine.

I'd say the question is, which one would you need most of?

A 1.1L engine is going to have all the power you will ever need out of a genny that's for sure.  If it's only 20 HP, that's a 10Kw head you can run.  I'd think of the top of my head it's going to be like 50 HP  and given the alt will probably be geared down, Power is not going to be an issue.
As for heat, in the house I understand you want to build, again I'd say that's not going to be a concern. If you want to heat the shed that may be useful but you'll still have plenty of power to turn on electric heating if it's not enough and further generate more heat from the engine itself.

design and sizing properly is likely far more important than whatever the difference in brake fuel consumption numbers are, the better the design, sizing, and implementation, the higher the overall efficiency.

What I'm thinking in suggesting Reverse cycle AC etc is what is going to be easier and more practical to implement?
With the heating of the home for instance, how far away will the engine be?  Whats the cost and effort in running pipes and setting up an internal heater system in the house? How much effort to make it look decent?  Same with the AC.  What about pipe work, losses in the pipes etc. Then, do you want to be running the engine on a hot day when you are making loads of solar that could run the AC without costing you a cent but you have to run the engine because to Drive the AC pump?
Maybe it will be better just to go with a small split AC and have year round Comfort that can be derived from the solar or by running the engine?

I think there is more to efficiency than just using all the energy in the fuel.
Something you can do with a split  Type AC in winter is use the engine heat.  If you ducted the heat from the radiator into the condenser of the AC, You will be able to make use of that energy.
I have been experimenting with that exact thing. Here it gets cold and humid enough for my AC to freeze up.  I put a draft Oil burner next to the outdoor unit and sealed one side and the top to the wall with cardboard so the airflow has to come from the side of the burner. It was as inefficient as all hell being a test BUT, I could run the AC flat out hot as it would go and the thing Poured the heat into the house and of course never looked like freezing up. In normal use it would drasticly cut down the time the AC ran because there is so much more heat available for it to use and put into the house.

now i have not considered in this discussion the possible longevity edge going to the diesel engine, typically they last longer than gas engines, however there are example of gas engines that have excellent long life history's

I don't see it as an issue. Look up the Hours per mile equation for car engines. It's a lot to start with.  In your application the engine will be leading an infinitely easier life than in automotive use.
We have pulled Subaru Engines Down in the yard with 500K KM on them and they still have the cross hatch in the bore and the bearings are fine. Modern engines unless they are a lemon last forever.  If I was doing one, I'd be adding in an extra large oil filter and either increasing the sump capacity or putting in an external resiviour.  You could also if needed put on an oil cooler.


Commercial engines all have huge filtration and huge oil capacity.  Probably don't on vehicles for packaging reasons and they are only designed for a 10 year life before the rest falls apart anyway.
My Nissan TD42 which has legendary life has 2 Full size oil filters and holds nearly 13L of oil.  500K Km on one of those for a rebuild is a bit short life. The other thing these Vehicles have is Very good air filtration. There are various ones depending on the exact model of the vehicle but most were a twin system with a Cyclone or double filters or just a hulking huge one.  Again, very easy to add to a stationary motor and often what you see on  large  stationary engines meant to put put big power.

my example of the honda 1.1 or 1.3 was only because it was the first one to pop up on ebay as widely available, cheap as a used engine from salvage yards,

My own proclivity with things like this is to buy 2, or 3 if affordable enough.  Then you have one for spares and a replacement that slots right in with everything else if you do have to replace it.
I'd also buy spares before you need them as stuff has a nasty habit of becoming unavailable in time.

whatever example used, beit honda, ford, volvo or whatever the recommendation that it might well be best to buy the whole car so that one would have all the requisite stuff to make it run, such as the computer, all sensors, wiring harnesses etc.

Yep. With what one needs to make a Fuel injected, computer control engine run now, I think you'd be Nuts to do anything else and,  By the time you bought everything as components, would be cheaper anyway.  We get asked for wiring looms for vehicles now and then. People shit a kidney when you tell them $1000.  It's a minimum of 2-3 days work to get one out and you have to destroy the vehicle in the process.  It's a huge job no one wants to do so  we sure as heck aren't doing it for nothing.  The other thing with so many cars having CANBUS where all the parts need to be coded to one another ( even headlights on some vehicles, I'm not kidding!!) it's not possible just to mix and match without having the computer from the stealer to code them.
Even pulling everything out of the car and putting it back together can require a computer reset.

I'd be trying to leave the vehicle pretty much intact as a front cut and use it as a mounting for the gen head if possible.  The wiring under the dash alone is a night mare and unless you are a really switched on expert, it's almost impossible to know what you will and won't need.  Just because you won't need the blinkers or the airbags, don't assume you can just cut that wire off.

I would be looking up what others have done before in this regard and if there are any vehicle engines that better lend themselves to conversion. I know the Prius is a popular candidate for obvious reasons but the process of modification is not easy although I believe there are Modules and things being made to make the job more plug and play.

These days, I think with solar, particularly if one utilises used panels, one could get away with the lawn mower motor and a car alternator pretty much.
Also looking to the future,  -IF- batteries drop in price as touted ( which I think is BS myself) and IF solar gets cheaper ( almost guaranteed)  then having set up as electrical power for the home  rather than relying on  take off from mechanical  inefficiency will become more viable.

While the first thought we have all had is use that waste heat and set up an AC from it, I think that needs to be looked at a lot closer these days.
It may satisfy the efficiency and utilisation mindset we all have ingrained but how well does it satisfy the ease of use, flexibility, cost and maintence Criteria?  I discovered long ago, while one can do all these alternative things, they rarely add on well or neatly to a normal home. I could do a lot here BUT the end result would devalue the home 100K more than what I could ever save.
An engine in the shed that I use power only on and forget the rest and solar on the roof does let me do a lot to save money and does not destroy the look and appeal of the place and also takes a lot less of my time and effort than a lot of other things I could do...... Hard as it is to break out of that mindset and want to experiment and play around anyhow.

[mobile_bob]

just to be clear on a few points

1. this is more of a mental exercise than practical application (at least up to this point)

2. also concur that PV panels, both new and certainly new have fallen in price to the point that it is hard
to justify the expense of either a gas of diesel power generation system, however

it really comes down to what it is one is trying to accomplish, sometimes it truly is the journey and not the destination
that is important.

in many ways, simply buying enough solar, enough charge controller, or grid tie, inverters, and batteries is a one time expense, as simple as signing the check and flipping a switch... nothing much to learn from that endeavor.

on the other hand, putting together and engine driven cogeneration system, as a diy'er is going to be a learning experience in a variety of ways.  understanding that even cogen can be a simple sign the check/flip the switch proposition as well.

everyone has their individual needs/wants, experience/education level, and what trips their trigger so to speak.

where one guy cannot imagine living in anything less than 3500 sq/ft (no idea how many sq/meters that is) many others seem to do quite well living in a small fraction of that space and be happy doing it.  where another guy would rather pay to play, than get his fingers dirty. then there is the whole lister vs changfa discussion of old.. there really is all sorts of folks, and it takes all of us to make the world go round, or so it seems.  throw in cultural differences and you have an interesting discussion.

i proposed the basis for this discussion based on the near unavailability of the changfa/listeroid engines being able to be imported into this country, with the thought that maybe there is another generation now looking or entertaining the idea of going  offgrid and not having those prime movers readily available, then as an exploration of what other possibilities exist?

to some this whole discussion makes no sense i am sure, to others maybe it makes a bit of sense and still others it might well make a lot of sense.

not exploring all options makes absolutely no sense, at least to me.

fwiw

[glort]

As the price of power has gone nuts in this country thanks to all the green Bullshit of unreliable power being cheaper which it has demonstrated beyond any possible doubt it's NOT as well as the unreliability and corruption of the power co's, a LOT of people have the going off grid idea here even in surburbia.

The solar/ battery industry over the last few years has been promoting the BS idea that one can put panels on the roof and a battery on the wall and never pay a power bill again and save a fortune.
I think that has backfired with too many people thinking they will wait to put on solar till battery's get cheaper and in the present climate, the solar industry is scratching for all the work they can get so trying to reverse the false ideal they have been previously fostering.

Dunno how many damn greenwashed Clueless Yuppies I have seen talking about getting an EV and charging it up from their solar panels at home. These virtue signallers don't have a Freaking clue the difference between a watt and a volt and think that solar is unlimited like the power than comes from the mains.

The ones with a clue these days are looking much more at solar for prime generation with a single bearing generator unit for backup.  As we are well aware of on these sorts of forums, those that are willing to get their hands dirty are getting further and father between. They want the dream but not the work to do it.

The off grid/ no power bills ideal is espoused by a lot of people that have no idea and often cannot be told that as expensive as grid power is here, you still cant even come close to generating it for the same price yourself in a standalone situation. Many of these greenwashed have the Fossil fuel Evil mentality so don't even consider a generator... till they wake up to the shortcomings of solar and wind if they are that enthused.


I was looking earlier on the real estate sites for Land with running water. I'd love to have a crack at Micro Hydro.  Seems so many ways you can do that but here finding suitable locations is tough.
Very few places in my state, North and south the opportunities are much better.  Then I think well with solar the way it is and falling back to generator power, I realise I have the capeability to go pretty much anywhere I want and be self sufficient anyway.  I would love to find a property I could just have a play and learn about MH though.

[mobile_bob]

"I think one would need to work out a basic design and Budget.
Do you want a generator as back up for solar or solar as a back up for the generator in topping batteries off? "


perhaps i have not taken enough time to think things through enough to explain my design philosophy or simply put
design "goals"

i don't see the purpose of a cogen unit as being  battery charger or for that matter a producer of electricity being primary, but rather secondary to that of a producer of heat.

because a combustion engine is far better at making heat than it is a producer of mechanical work (most of the fuel is lost to waste heat and a relative small fraction is converted to mechanical work.

so my focus with cogen is heat generation, or rather heat recovery and putting that heat to work.

i for one see a need for a furnace in the cooler/cold months of the year and a combustion engine is a pretty good furnace in my opinion that just so happens to also be able to drive an generator, an A/C compressor, and other things like pumps which would be useful in moving that heat to where i could put it to best use.

what i am suggesting here (as i have in the past) is a departure away from how we view an combustion engine, from one of a producer of mechanical work to one of simply a producer of heat.

i think once we cross that mental hurdle, the choice of diesel or gas based on typical BSFC numbers become irrelevant, or largely so.  the argument for one or the other then comes down to cost, ease of application, availability, fuel stability (less of an issue if diesel, propane or nat gas, and for that matter even pump gas "if" the system is sized properly, used effectively, follows good design which would mean not having fuel sitting around unused for months at a time.

for me viewing the combustion engine as a furnace or producer of heat is really pretty straight forward, and recovery of the vast majority of the heats available attainable fairly easy and diy friendly.  having crossed that bridge being able to then look at the furnace as having a pto that i can drive generators beit for AC or DC production is then incredibly simple.

[glort]

Well why didn't 'ya say so in the first place there Bob?? 

Here is one, sorta on your wave length I have contemplated......

I play around a bit with waste oil burners. While I prefer things that spit out 600Kwh of energy and regard them as routine, getting a useful amout of stable and reliable heat for a home, say 5 Kw worth, is not so easy to design in a burner for a number of reasons.  If we burn that waste oil in an engine, a Diesel as it has to be, the a reliable, steady 5 KW that is very safe and predictable is a walk in the park.
Using a water-cooled engine we can easily get the constant heat we want or vary it.  We can get more heat from loading the engine up, say by increasing the electrical load if it is a generator which gives I higher fuel burn producing more heat as well as potential using the electrical power say in a resistance  or utilising and AC setup. 

One thing that frankly irritates the guts out of me is the incessant question of how much fuel does a burner consume an hour?  My Immeadiate mental thought is " Who Fking cares?  The more you burn the more heat you get" but I try to answer more helpfully and explain this isn't MPG on a car, the more fuel the more heat.  Some people seem to be impressed by low fuel consumption. I tend to think " How weak is that? Wouldn't heat a  Chook shed.

Despite my initial ignorance, it is quite easy for me to think of an engine as a Burner for heat energy.  They just tend to be way smaller than I am used to playing with but in many ways for the average person, far more practical.

If Memory serves, the Honda Co gen systems were mainly aimed at heat production and power was the by product. I believe they were basicaly a replacement for Gas heaters.  You got the same amount of heat as you would have the gas but got the power generation as an added no cost Bonus for the fuel you burnt. They were a watercooled engine with a very efficent HE on the exhaust and also had a substantial intercooler for the oil in the sump as well.  They did not miss too many watts of power or let them go wasted.

I wonder why they were not more Popular?

Looking them up and getting an idea of the design would be a good place to start.

One thing with the AC side of things is you can use the left over  " Low Quality" heat very well.  anything under about boiling point of water has a non-viable heat transfer ratio but even 30oC heat is loads for a reverse cycle setup.  The AC can condense a lot of low heat into an amount of good heat and act as the distribution conduit.

[mobile_bob]

seems like we have circled he bull and got him cornered

the honda units never really took off in my opinion because they were a bit too small
they were made to satisfy the needs of a typical small japanese home, which by US and i suspect other standards
was just too small to be be of much use.

iirc (and it has been years since i read up on these and other units) the honda units were good for 1500watts and had no battery storage included of anticipated, although i think they were gridtie and as such i guess the grid is the battery.

while being over 90% efficient the domestic hot water production was quite low, kids here in the states spend hours in the showers and i know i consume copious amounts of water soaking my old hide back into some sort of mobility.

i remember thinking at the time, again about 20 years ago now, that if honda made a unit about 3times larger it might well find broad acceptance here in the states.

the market is also fickle as heck, seems like every time that gasoline approaches 4 bucks a gallon, everyone is all hands on deck to find any solution to lower utility costs, and the minute it drops to under 3 bucks, everyone drops the ball and the interest melt away like frosty in august on the salt flats.

diy cogen or diy power production is just not sexy enough to attract big dollars, so funding these projects is out of the average joe's pocket, and that is a challenge to say the least.

i know for a fact that a good diy guy/gal can compete well with any of the big boys when it come to cogen efficiency
when it comes to competing on just about any other level, the game favors the big boys.

its always a tall order to sell someone something at a significant increase in cost something that he already is getting done without incurring more upfront costs, especially when it is rarely seen let alone understood.

far easier to sell a man a shiny new pickup truck he can show off to the buddies at the golf course, bar or work.  even if the darn thing is 70 grand! and his 10k buck pickup does the same job!  you can show him the flaw in the economics of that pretty easy, but he will still go out and spend it. while he will likely never pull out a functional furnace and replace it with a cogen even if the price difference is as little as 5grand different, not even when the 50 year old furnace decides to die one cold night (they always die at night, coldest night of the year, and especially christmas eve when the family is all home)

moving on a bit...

back in about '07 while developing and testing my s195 based trigen, i came upon a white paper from victron where they did exhaustive testing on three different classes of systems  3-5kwatt, 5-7kwatt and 7-11 iirc. they tested units made by several world leaders at the time in each class, and graphed out BSFC numbers for each for comparison.  this was the first time that we had a relative target to work toward.

i set up a test cell and ran some 100 hours of testing of my units, measuring BSFC generating AC and DC, and a combination of both (running the st head and twin 110-555jho alternators and a couple of other leece neville alternators, one fitted with a water cooled stator)  what i found was my unit which was in the mid class was about dead center of its class, mine did better numbers that 4 of the 6 tested and worse than 2 of the 6.  that was actually quite an enlightening experience that clearly demonstrated that a diy'er can design and build something that can compete with the big boys at least in BSFC efficiency.

the next move was to recover and measure the heat from the exhaust, which is in most ways more difficult than that of the cooling system. 

with what i call a bit of divine intervention or inspiration, i designed a heat exchanger for the exhaust, with which i was able to produce 60gallons of 140 degreeF domestic hot water  from an ambient 70 degree startup in one hour with the engine running under full load of 8kwe. the bsfc worked out to be 9.9kw/hrs per gallon of pump low sulphur diesel fuel (by weight). the exhaust temperature entering the exchanger was 640deg F and exited the exchanger at 240 F (i wanted to stay above the boiling point of water so that there would be no condensation within the exchanger at operating full load temperatures.

because the system was to be "batch fired" that being run times limited to one hour, the internal design of the exchanger takes advantage of this condensation to effectively convert to steam and self clean the unit.  efficiency in testing remained the same, 640f in and 240f out under the same load conditions and the same ambient temperature.

the exhaust heat is high value heat, being much easier to harvest due to the higher temperatures of the exhaust gasses leaving the exhaust port, but more difficult to design for.

the water coolant system is very easy to harvest from, simply tap and move the heat to where it is needed.

i got lucky and found a 50gallon hot water maker, basically a storage tank with heat exchanger coils, typical of those used to make domestic hot water from a boiler system on craigslist in seattle about the same time, it was one year old, and replaced because the new owner had several kids and replaced it with an 80 gallon unit.  another small taco pump a temp switch and i can harvest heat from the cooling system to make domestic hot water.

taking the measurements, doing the calculations and the unit returns right at 88% overall efficiency, in that combining the btu values of both heat sources recovered and the btu value of the electricity generated factored against the btu value of the fuel burned.   that number can be improved by figuring how to harvest and use the low value waste heat from the exhaust heat exchanger, an oil cooler exchanger, and possibly recovering heat of convection of the engine block, generator head etc. (although the latter can be estimated and accounted for as space heat of an engine room/shed in winter as the heat is useful then)

given these numbers i became quite obvious that at least in wintertime the unit can compete with the power company, and best it if one were to use a 50/50 mix of diesel and waste oil, although there is the argument that such mixes accelerate engine wear, to which i would argue that the accelerated wear cost is acceptable and should be seen as a consumable. something like i am ok with spending some time and 200 bucks in repair parts for the chanfa to save 800 dollars in fuel, net savings 600 bucks.

i just want to know "if" one can attain similar results using available prime movers we have today.  while i have enough changfa's to run the rest of my life, where is the fun in that?  while there is more to learn using the changfa, my thinking there is much more to learn using other more commonly available engines, while being more relevant.

at least for me, living where i am now, there is  real need for heat in the winter, and i will be either burning nat/gas in the 50 year old furnace or in a cogen... and i don't think solar panels are likely going  to have an impact on this need.