Micro CoGen.

Must be a pretty rare beast to get hold of. Will you be keeping it or onselling it?

Been thinking a bit more about this in practical terms to my own situation.

I made 102 Kwh yesterday with my solar. Very respectable figure and OK wile I can grid back feed but with the legislation that we all have to go to smartarse meters here, that will end my party.
If I went off grid, a practical battery pack would not cover my needs.

My problem will really be heating. I need that mainly at night. Running an engine may be difficult to get it quiet enough as even though I am on acreage, neighbours are only about 20M away on one side.  Cooling wont be so bad, I could run the AC during the day with the solar and cool the place down and I'd ask mate to help me with a solution  for a chiller for cold storage for night use.

The solution would be thermal storage.
A cheap , easy and practical way of achieving that would be with water heater tanks. They seem very plentiful at my local scrap yard and I have picked up a few for nothing in exchange for what I leave.  I sometimes pick up scrap now just so I have something to take there just to keep them on side and give something back.

400L tanks are common here. They usually have 3.6 and 4.8 KW elements in them, on occasion you see the pick of the bunch, the ones with an upper and lower element . But not often. 
In any case, these could be used for thermal storage.  Plumb the engine into the tank and let it heat it up from the heat energy and if one were charging a battery pack, once that was full, then the heating elements could be kicked in.

2x 400L tanks heated up to 90oC  and taken down to 30oC would store 55kwh of heat.  That would be sufficient for my needs. If it were not, a 3rd tank could be added.
I would think that the solar alone would cover the 2 tranks on sunny days, May take a decent run time on an engine for the crappy ones though.
As for fuel consumption, 7L would cover the requirement with reasonable efficiency.  With a 12 HP motor, about 9 Kw could be produced so call that again 6 Hours run time.

I have a 12 Kw Induction motor up the back  which would be a good match for this setup.  Having a fixed load like a resistive heater is the perfect application for one of these IMAGs which can be VERY finicky with varying loads.  For battery charging, alternators could be used ( I'd go 24V for simplicity ) and the load on the Imag dialled in with a PWM controller on the element and some tweaking of the caps.

This would be a fairly simple heating system with the benefit of being a battery charger or power supply as well.  Would be nice to have a larger engine.  I have a 30 HP twin Diesel but that is aircooled and the other is my om 617 5 cyl merc motor which is probably a bit over kill.  A 20 -30 Hp watercooled would be ideal. Plenty of heat and power with much shorter run times.

Quote from: mobile_bob on August 10, 2020, 06:11:49 PM

under the scheme example given, i don't see long runs times being needed or desirable in the summer months.

The difference in our Conditions.
Here AC is essential .  It literally gets hot enough to be a health risk not to mention the problem of not sleeping. Luckily the night temps do Drop a Lot but it's also not unusual to have one that stays well above 30oC.  By the same token, a lot of nights can drop below 20oC after a 40+ Day.  There were 3 days here last year where the temp did not fall below 40oc ( 100f) till after 9 pm.
Even when the outside temps drop, the house is heat soaked and that's when insulation works against you. Open windows aren't enough.  I have put fans in windows and it helps but still a lot of nights where the temps are still too warm.

Quoterunning long enough to make the needed domestic hot water and not much else, do the rest with solar.

I keep getting confused as to what the goal is here with regards to the heat/ cooling source. :0)
I have an aircooled  165 and it is without a doubt my favourite and smallest diesel engine. The thing is rated at 3 Kw I think it is and will out pull my 6 Hp engines, all of them, all day everyday with out smoking, overloading or anything else. It's the little train that could.

If we are talking about an over all practical system, I would suggest that if one had enough solar to run an AC, one also has enough solar to heat the domestic water.  In the example, a 165 is going to supply 3 Kw of combined energy at best, twice a day in an hour run.
6 Kwh of solar where I am would be a walk in the park with anything that was capable of driving a small AC, say 2-3 Kwh of panels.  You could easily have the hot water taken care of before there was any need for running the AC unless one lived in virtual Dessert conditions.

Solar has a ramp up and ramp down before making full power but the power it does make could easily be channelled to a water heater. I would Imagine that a 3 Kw system at the latitude I am at least would have no trouble generating 3 Kwh or more before 9am when the total output was probably never above 2 Kw or less. Even though the solar hasn't come on a whole lot, in the case of water you can still " bank" and accumulate that energy.

Friend and I are working on a small, cheap and very easy built controller for this exact purpose.  It stores the available power from the panels in a capacitor or bank thereof and acts like a voltage switch. Instead of the panels being dragged off their curve by being over loaded by an element, (even a low voltage one will still pull them down at less than optimum output) it gives the panels a low loading which keeps them on their  optimum power curve and then when the cap is charged to the full voltage, that power is dumped into the element l It can Cycle at 100Hz or more with ease  and the thing is it lets the panels develop the full power they can at the current lighting condition ( even if only a few watts) and transfer that into the element.

It will work with any element at all.  One could plug an unmodified electric kettle or frypan into an array and run that off DC because the controller creates an AC like Zero crossing wave form that would stop any arcing, maybe even better than a regular AC output.  We have proper Circuit Boards printed and are just running tests now. We have over engineered everything after seeing how electronically weak some of the far more expensive ( Ridiculous for what they are) boards are built and to give this thing virtually unlimited within practicality ( and not so) power handling capabilities.  5 Kw wouldn't faze it and if you wanted to go 10, change a couple of mosfets, make sure you have adequate heat sinking for what you want and off you go. Built it yourself in an hour or less and cost will be $50-100 depending where you get components.

You could run this with other loads at the same time as well. Just set the voltage limiting resistors according to the " Left over"  power and to leave adequate for the AC or whatever and  it will run when there is sufficient generation and turn off when there is not.

Quoteyears ago, i read about an african village that used a trough reflector/concentrater using rock salt as the absorbent in a batch fired ammonia system, it made 20lbs of ice per day, and required frequent cover to cycle the thing in the summer sun... they had lots of help and even 20lbs of ice to folks that had never seen ice was most welcome.

I read of something similar. It was a bigger system in the middle of no where. They had water and from memory they lit a camp fire for energy.  The difference it made to that village and surrounding was incredible. The village with the setup earned money from selling the ice and the people that bought it took it back to their village and could preserve their food supply so they had far less feast and famine. Something so simple was quite an advantage to them.

Quotemy problem is, as much as i would like to work with an ammonia system, you have to have a license to get the stuff, and finding a licensed refrigeration guy that is ammonia certified is about as rare as hens teeth around here.... much easier to find that sort of guy around fisheries and big ice house/cold storage buildings/units.

Reading more on absorption systems, I think I get the picture a bit better.  They are basically Cyclic for the most part.

I'm wondering if something like LPG couldn't be used or some thing with similar properties.  Use the heat to Boil/ superheat it and raise the pressure then allow it to depressurise if not condense through another line that does the chilling. LPG may be the wrong Medium, maybe something like Alcohol would be better where it could be phase changed and re condensed.

One thing with LPG, I have used it in a number of AC units and it works well. Real well.  Given the cost of refrigerants here and the over the top rules for environmental concerns for venting it, LPG is a great alternative.  It runs about half the weight of R134a so I just charge the pressures watching the high and low sides with Gauges.  When the pressures are correct, the system is properly charged.

QuoteThe day comes i find that guy around here, is the day i really get excited and go to work.... as to me it would be the holy grail of co generation, making use of the waste heat in summer to cool with.

I wonder how physically large an absorption system would have to be to use say 3 Kw of heat in terms of Physical size and amount of ammonia and water etc?

Do and why would they still use absorption systems in commercial applications over Compressed systems?  What would be the heat source?

I don't think it would be such a trick to get or excede the efficency of commercial units. They have a lot of paramarters they have to work to we don't. Emissions for one, weight and packaging for another, autonomy- set and forget operation that a DIYer is not going to be as concerned about as somone that just wants heat/ power and doese not want to know about it.

With your Changfa's,  before getting too excited about something new and different, Have you considered gas fumigation?  Run the thing as a diesel but have an amount of gas entering the airstream  which is combusted with the diesel to lower it's consumption. This can be very easy in the setup you are chasing, can just be a fixed amount of gas and the govenor on the engine will add more or less diesel as required. It works on power output/ RPM not mixture.  Probably not that hard to stage the injection high and low if one had the need.

I think my suggestion on using the low value heat from the engine with an AC pump has merit in chasing max efficency. You could be using the exit temp of the exhaust through the HE and pulling a LOT more heat out of that which would bump your Numbers. You could build the condenser at the end of the enclosure of an engine and draw air past the engine so all the heat from the engine block itself and accessories even like the alternator was pulled through the AC condenser and put to use. The colder the weather the more effective this could be.

The exhaust could go through some pipe work after the water heater as there is still a lot of energy in that and have air blowing across the pipes much like a modern gas furnace which pulls the the exhaust down to 40oC or less so much more heat was extracted or maybe put it through another  Condenser on it's own that could be blocked off or disconnected in Summer. With that you would be able to use all the Cooling heat, all the exhaust heat and all the low grade heat emitted from the engine and your alternators as well. That should push the efficiency numbers well up indeed.

The one thing I see that would need to compliment a setup of the type you describe is cooling. I don't it's cold everywhere all year so having a system that could use the heat to make cold Like an absorption system would also bump the numbers the right way.  I Can't get my head exactly around how absorption systems work but obviously they do and that's it.  It seems those that can understand them could build one in a DIY application as well.  That would be able to make use of all the heat which would otherwise be not needed in summer and should make for a potential powerful cooling system in addition to the pump.  Furthermore, which it might be easy to store heat in water, other problems come up with storing cold. They could be over come with large tanks of salt water.  Ice is a VERY efficient cold storage however there are a Lot of difficulties with that especially in getting the cold back.
There are ice based AC systems commercially available which can be studied to se how they do it but again to yours truly show the difficulties more over than DIY solutions.

I looked at this a while back and concluded that 2X 1000L  drums of salt water that would be buried in my yard surrounded by coolroom panel which is available free and fairly readily would be a worthwhile system for my home.  1 Tank would do it by 2 allowed for miscalculations and rather have to much than run short.  I could cool the Brine at night when the temps were low using a spray of water on a condenser for low grade cooling which would be enough at certain times of the year and use excess solar to drop the temp some more during the day even when the house was being cooled. I would have plenty of power to do this.  In winter the plan was to heat the water using an engine which, at the time of planning , would also give me the ability to make power I could use.  Now I have that covered, the power could simply be used in  resistance heating or with an AC pump setup.

The other alternative was to heat the tanks using an oil burner.  One useful side effect I saw to this was the heat that leaked from the setup would warm the soil and give me a great spot for a small greenhouse that I could grow vegetables in winter. I have learned it's not keeping the Plants warm thats the trick but rather keeping the soil warm.  This would be a real Coup in efficiency if the heat leakage could even be utilised.  It was proposed by some that insulation would not even be needed on the top of the tanks for this reason and that the correct depth would be workable for keeping cold in but allowing enough heat for the plant roots.

Perhaps low Grade exhaust heat and the exhaust itself in small amounts could be used in a greenhouse as commercial greenhouses do admit an amount of Co2 in order to double the atmospheric concentrations that make plants grow better. The exhaust after the water heater could be run through some pipes with air being blown across for home heat ( wouldn't be hard to design Vertically with small condensation pipes on the bottom of the runs for draining that off if needed or run the exhaust through soil or into a greenhouse to use what was left.

Using the heat in winter is easy. Making the setup seriously efficient in summer I see as the real trick and where the real numbers could be gained. Without it, you basically do have a Furnace in summer that's going to be of limited use thermally and go back to the mechanical energy being the only real useful component.

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.

Sorry If I am being obtuse  Bob.
It is not intentional, Just unfortunate on my part.  :0(

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.

Quote from: mobile_bob on August 08, 2020, 08:48:46 PM
money enough to put it in a crate? just money to ship both ways!
remember you can't take it with you!

Problem is, would it even be let into the US?

There is so much you can have and do in the US you can't do here but it never ceases to amuse me how they are so tight on something as harmless as a small engine!
Can't have a slingshot or a Cross bow here but the only concern with any engine is you aren't importing one with the bores or sump Full of Crack or heroin. 
Barring that, they have a lot more to worry themselves about so Hurry up and get that thing out of here.

Have a look at the local fleabay Listings:

https://www.ebay.com.au/sch/i.html?_nkw=stationary+diesel+engine&_sop=7

Few random thoughts.....


Don't know what your experience with solar is bob but with 500W of panels I'd be flat out powering a tent.
You never get near the panels rating so if you want 500W of panels, Put up a Kw worth... at least! If you put up 4-6 Kw worth then you can be assured you will have your minimum requirement in pretty much any weather.  While overkill, it's far from uneconomical or non viable.
If you want 20 Kwh a day, different story.  
I recent'y read an article that added up all the losses from a 250W panel. the conclusion was one would get about 188W of power from it IF it were generating 250W in the first place which would be at very limited times.... if ever.  This takes into account wiring and inverter conversion in grid tie but I would assume an off grid charger would not be any better.

How much would you pay Per Kw for panels in your area new or used?

Here panels are regularly advertised for stupid prices. I have no idea where the people dream up these Ludacrous numbers, Often it seems on what they paid 10 years ago even though they have just had a new system installed and got their money back on the old one anyway. I like that. I put in a realistic offer which they dismiss as lowball.  I use other accounts to put in similar offers about once a week. I get back to them after a month and I get them sometimes less than I first offered.  What makes me really laugh is when they will advertise them cheaper than the first offer I made they told me to shove up my arse.
Don't go by what they are advertised for. You never know what they sold for but here it's rarely near the same thing.

With running the 2 X AC  Compressors, how many hours a day would you need the heating or cooling?
Granted, where I am I see some rather extreme temps but even on the average summer days, one  would still want to have the thing running a good 6 Hours a day minimum.
Much of that COULD be taken up by solar and save the engine wear and tear and fuel.
The benefit of running 10 Kw of panels would you would have your 500W for batteries and a couple of Kw for heating.

Even if you paid $100 Kw, that thousand dollars is going to last 10 years, probably 20 even on used panels and be basically maintence and hassle free with near no running costs once set up.
You will need an inverter and charger but they are getting cheap now too and should have a 5-10 Yr life time as well. With that sort of solar you could get away with the most basic engine as it's only going to be needed for extended bad weather so an unmodified engine using a straight alternator for topping up.  Might use 5L of petrol a year.

I have taken to " Heat sinking " the house.  Crank the heating through the day when there is solar so the walls and furniture are brought up to temp and are not acting like Ice bricks at night.  Same in summer. I found it much more economical to get onto the AC early so it's just keeping the temp rather than trying to pull it down once the heat has penetrated the walls and heated the furniture etc.
The other thing is the AC is Pulling from the day temp of around 20oC in the day as against  <5oC at night. makes a big Difference.


Idea for a small watercooled petrol engine..... 4 stroke outboard.
Don't know how much they go for in  your area, but they are getting cheaper here.  You can get them in whatever HP you want and may be able to pick up just a power head or one with a damaged gearbox etc.  
Other one might be a watercooled Motorcycle engine. Would have the advantage of the built in gearbox to make gearing the gen head even easier.

I wonder how well an aircooled engine could be made with oil cooling only? Take the fins off the flywheel and put a squirter in the engine casing firing up under the piston.  Maybe another port pouring oil up into the rocker area to keep the head cool.  Small external Oil pump and one could easily then put the oil though a HE like one would do with water.  Power steering pump could be easily modified to make flow rather than pressure but pressure only happens in restriction anyway. The casings are also ally so maybe put a squirter firing lots of oil to take away heat there too.  instead of putting the water externally, use the oil internally.  The exhaust could be jacketed and use the oil through there too before it goes to the HE.
An larger engine  like an 18 HP under driven say 50% would give more surface area internally for the oil to take the heat away.  Maybe a Piece of aluminium Tube could be brazed around the head where the cooling fins go if internal oil cooling wasn't enough.

This would be an easy way to increase sump capacity and just plumb in an external oil filter.

On that thought> I wonder how much the life of a basic air-cooled China " Predator" type engine would be increased buy having it's blood put through a proper Filter? Far as I know, it's only the  22 Hp and larger twin engines that have a proper spin on filter so something that does not have any filter may benefit in extended life quite an amount.

These small aircooled China engines are cheap enough to muck around with and spares are so readily and cheaply available, it would be hard to experiment and have a total loss anyway.

I have often wished there was someone here I could just send my roid to to have it done over and made right.
Been going to do it for years but I just don't have the motivation on the tools any more.  Simple as they are, I have learned there is more than one trick to these engines and a lot of traps to look out for.  I'm not interested in going through the process of learning another skill set. 

If I could just drop the thing off somewhere and pick it up all done I'd be happy.  Wouldn't like to open a branch of your Business in Sydney Australia would you??

Money I have, Motivation I don't.   :0(

Quote from: mobile_bob on August 08, 2020, 01:52:39 PM

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.

Quoteas 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.

Quotetechnically 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.

Quotedesign 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.

Quotenow 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.

Quotemy 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.

Quotewhatever 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.

Quote from: playdiesel on August 07, 2020, 04:25:30 PM
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.   

Quote from: mobile_bob on August 06, 2020, 06:38:24 PM
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.

Quote from: mobile_bob on August 04, 2020, 05:48:24 PM

about 90% of the time, when the loads were not balanced, that "sonofabeeatch" would scream like an air raid siren
and i had to use both in ear and outer ear protection, it was horrible.

I don't know what the differences are and I know the US System is a lot different to the native 240V Systems but I have played a lot with Imbalanced IMAGS and found no problem at all.
I have read a lot about heat build up but in an IMAG it makes no difference other than you can only get a lower output.  I put this down to the fact the machine is working a lot less and has in fact extra heat sinking capacity and cooling.  Never noticed any untoward noise but Imags tend to sing a little through the caps anyway but it would be nothing that would disturb anyone at any distance and certainly  wouldn't register in compared to the engine noise.

I haven't played with any 3 Phase gen heads like this and have often wondered if all the cautions about making sure the loads are balanced are just more over pedantic best practice hype or if it can really make a difference on small output units. I'm sure unbalancing a 100Kw+ unit may cause other problems but for something 5Kw or so. may not be that bad.... Maybe.
Could also depend on wether it was a 110. 220V Unit or a 415 Type where each leg is 220 and the configuration is different.

I notice a lot of 3 phase generators are sold here that have 220V taken off each leg and while they are supposed to be balanced, I would guarantee 99% of the time they are not and only are running off a single leg when used in single phase.  Maybe you can't pull 100% single phase power off that leg all day long but I'd be pretty sure you could pull something decent or these things would be letting the magic smoke out on building sites everywhere.

There are Phase controllers that can create 3 phase from single ( in our power system anyway) and can combine 3 phase to Higher current single. 
The latter would be ideal for load balancing 3 phase heads. 

Quote from: playdiesel on August 02, 2020, 09:00:59 AM
ya there is no way that cast iron is good at 1000 RPM. One thing I have learned from going through a bunch of these is never assume anything with a Listeroid

The RPM would depend on the offset of the counterweights in the crank or flywheel. Iron pistons are not that uncommon and just throwing in an ally one might cause a LOT of imbalance.
Don't rush in with presumptions, make sure what the thing is set up for because it's more than likely it WILL run to 1000 RPM very smoothly and putting in an all piston will turn the thing into a Jackhammer if the flywheel or Crank counterweights are then too heavy.