240D engine as CHP generator
 

Has anyone used a 240D engine as a combined heat and power generator? I'd like to run it on veg and produce electricity and take the coolant and run it to an A coil in the house for heating. Has anyone in the forum done that with a 240D engine?

I've read about someone powering appliances in their house with an inverter during a power outage, but nothing to the extreme you are talking about.

I'm not sure how much electricity you would get out of it. Perhaps others will know. Probably not enough to run an entire average house.

With enough work, I'm sure it could work. I guess the question is, how much work do you want to put into it? ;)

Some ideas
 

I thought about it myself and here are my thoughts.

1) Engine in car - if you use an inverter hook to the battery then you will only get about 1KW max from the inverter. Assuming you get a heavy alternator which put out 100A. It is still quite good and just leave the car in idle or rev it up a bit.

2) Engine out of car - You can hook a generator head to it. Rev the engine to 3600rpm, I think most head take 3600rpm. Head is around $300 from Harbor Freight. This will give you may be 5KW or more, enough to run a whole house.

3) Run the coolant to a heat exchanger to heat your hot water or radiator in the house. It is possible but may be messy and need some inventiveness. Never thought of this.

4) Sync the power from the generator head back to the grid to feed surplus electricity to the operator. It is doable and you can sync it manually but it is dangerous and a try and error process. The electricity company may not let you do it. An automatic phase synchronizer is out of the questions. It is very expensive and not within the realm of a DIY.

I think in general it is doable for off grid use. An inverter is the best, and heat your hot water. Any members have other ideas?

A 616 can produce way more than the needed power to run a house. With the right setup attached to it you could probably get 50,000 watts or more. Fuel consumption at that output would be pretty high though. Even at normal levels, I'm betting that you'd need one heck of a supply of veg oil. :eek: Running at 3600rpm with a moderate to low load would probably use at least 1.5 gallons an hour

I don't see why this wouldn't work. A solar thermal hot water system works basically the same. A panel or tubes on the roof are heated from the sun as the coolant is pumped to either an in-tank or an external heat exchanger.

Hot water tanks designed for a solar application should work.

And, depending on your climate, hot water is one of the biggest energy users in the house. So not having to heat your water would lessen the amount of elecricity that would be required in your home thus lessening the output from the engine.

I found this in a few minutes of searching: http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_8795_8795

10 kW generator head, spin it at 3600 rpm and get 9600 W continuous. Takes 18 hp, says the website.

Peak mechanical output on a 616 (62 or 67 x 746) comes to either 46 or just under 50 kW, but you'd want to stay lower for a continuous duty situation.

What are you wanting to power?

It would work. But you need to be inventive to hook up the plumbing. This is free energy. It all depends on how much effort one wants to put into this kind of project. Need to do a cost benefits analysis as the payback period can be long. This includes solar power, Prius, hybrid cars as the payback period is long, very long.

You would also have to rig up a governor for the engine to keep it at 3600RPM under any load...

Ok, here are my thoughts:

• 68 HP ~= 50.7 kW
• If you're going to use the engine for heat you have two sources:
  1. Engine coolant - used for regulating the engine temperature
  2. Exhaust - plenty of heat, may consider an air-water heat exchanger
• For the engine coolant you need three things to consider:
  1. The engine is not yet at operating temperature, coolant is circulated until it reaches an operating temperature
  2. The engine is at operating temperature, cooling capacity is sustained by heating house water - water / water heat exchanger.
  3. The engine is at operating temperature and the house heating needs are not capable of cooling the engine - use something like a bypass through an external radiator / fan

On the generation side - you need to decide between using 12VDC or 120VAC. Obviously one is easier for charging a battery array (think of it as a crude power smoothing), and then if you're not running things off of DC, use an inverter - there are various sizes for renewable applications, however, the larger inverter you want, the more it can cost.

For AC, you can run a synchronous generator at...well...its synchronous speed (with a 1:1 transmission ratio): here.

For a 2 pole generator - this is 3600RPM for the 60Hz power in the US (4 would be a reasonable 1800RPM). With that said, if you wish to tie into the grid, you need to make sure that your sinusoidal voltage fluctation is consistent (synched) with the grid - not fun. Synchronous wind turbines have interesting starting procedures because of this.

What kind of duty cycle would you operate the engine at? Would you size the generator for peak load, or for continuous operation?

I know a guy who has a solar thermal panel on his house here in MN. He installed it about 20 years ago. He ran his costs and it was about 7 years pay back in energy savings. Obviously many variables go into the equation...just stating what it was for him.

$0.02
 

Graplr - what I meant is that some projects are difficult to justify except the feel good factor. I think Solar Hot Water ( convection type ) has the best return and short payback period ( your friend's system ). Very little mainenance and abundant amount of hot water. I had one on my roof until the tank leaked. The water was so hot and abundant that I can 'sell' it to my neighbors. As for Solar cells to generate electricity, the capital investment is huge and the payback period is long. You may get a tax credit for solar cells. Same goes for hybrid cars as you only save, may be $40, of gas per month but the premium is $5000+. Even project like this post is not really worth it except for the inverter. After you added the head, a governer, wiring, switch panel, plumbing, bypass radiator etc it would come to a considerable amount of money plus your sweat equity.

What I'm seeing here is that the engine will produce an abundance of power, and the generator head needs to turn at aprox 3600 rpm. You could utilize the transmission to take advantage of that excess power and gear up to your desired RPM output.

Well it's just a thought

Agreed. Most people do it because they like alternative energy, not for the financial savings. And I also agree that solar thermal has the best return on investment.

There used to be Mercedes Engine Powered Thermo King Generator sets for the Refridgerated Trucks. They already have a Generator on them and a proper Governor and put out 220-240 Volts. In 1990 when I did that sort of work there were still some in daily use.
Might be easier just to find one.

The most of the Gen sets I have experience with ran at 1800 rpm when at full load.

There also may be a Marine liquid cooled.Exhaust Manifold for boating use. That would give you way more heat than the Radiator could put out and at cold temps that Engine may need to keeps the heat to itself.

I don't know anything about running generators at a certain RPM, but 3600 is going to be pretty loud and pretty obnoxious after a while. Any method you could come up with (gears... transmission... somebody said something about poles on the generator???) to run 1800 instead of 3600 RPM would go a LONG way toward making this a more practical machine after you build it.

Also, is the engine's water pump strong enough to circulate coolant the distance from the generator to the house heating equipment and back with enough leftover capacity to ensure the engine is being cooled enough. Something to think about is that water pumps do fail, leak, whatever from time to time, and perhaps it would be worth looking into building some sort of safety for that, sort of like a low oil pressure shutoff, so that when the circulation system finally fails, the engine won't toast itself during the interval between when it dies and when you finally notice the house isn't getting warm anymore.

Since the speed of the engine is mechanically governed by the accelerator pedal and associated linkages and things and most 240s don't have tachs, I'm not sure how convenient or easy it's going to be to rig up a governor to keep the RPM constant to run the generator. When you do figure that out, would it be possible to tie some sort of low oil/low coolant engine shutoff safety feature into that mechanism? If it's already connected to the IP linkages somehow then it might be easy enough to have the thing shove the stop lever instead of throttling up when it detected those conditions.

If I was going to the expense of building this thing, (I agree with those that are saying the return on the investment is going to be a while showing up; you'd have to REALLY like alternative energy to go to this much trouble) -- I'd want a few of these safeties I'm talking about to keep it from exploding itself -- and I'd definitely not be able to stand hearing a 3600 RPM diesel roaring away constantly any time my house needed electricity. 1800 wouldn't be so bad.


Just my if-it-was-mine two cents. It's not my project.

Also, in response to the particular Northern Hydraulics (I keep forgetting they're Northern Tool and Equipment now, you'd think i'd remember it eventually) generator head posted earlier in the thread -- that particular one is only rated at 80 amps @ 120V which i'm assuming most of your house is. That's not a whole lot to run a house on. It would be fine for an emergency like a winter snowstorm if you managed the place some. But if you look at your breaker box, you've got way more than an 80 amp capacity in your house IF you ran everything to capacity. Of course everything doesn't run at the maximum its breaker will allow, far from it. But if you add up the wattages/amperages of your coffeepot, two or three stove burners, the fridge/freezer and deep freeze, possibly a microwave or a toaster, and a few of your electronics (TV, computer, etc) -- and the lights in the house -- you're very quickly approaching something almost like a wattage limit on that particular one. You *might* be able to get away with it IF you aren't running heat pumps and a hot water heater. In fact, since the hot water heater is usually the biggest load in the house, by eliminating it you might well be under the capacity of the machinery. But... it's something to think about. I'm not saying that one isn't perfectly adequate. But i'm saying your whole entire house, if it's all turned on at once, probably WILL exceed the capacity so you need to make a pretty decent analysis of your anticipated use of the thing, anticipate a few emergencies you weren't expecting here and there, and be sure your generator head really is sturdy enough to carry it all constantly.

Things I would be most concerned about:


The engine is designed to run at a variable RPM

Fuel costs, and if your running WVO you service life is going to drop considerably

The governor

Do you already use heating oil? If so, how much an hour?

Gearing it down would be wise. I would use a manual trans to avoid TC loss.

You can also change the gearing every other day to get the engine into a different rpm range for a while

AS for the coolant, Id imagine the engines thermostat would regulate the engine temp just fine. When you start it, minimal coolant will leave the motor until its hot. I would consider a water jacket on the exhaust.

The governor is simple. Get one of those audiovox cruise control things and rig the magnet pickup onto something spinning. You fire up your toaster, 1500 watts puts drag on the gen head, the cruise control dumps more fuel just like your climbing a hill.


Put the whole thing in a sound insulated box next to your house with a good muffler and you should be fine, maybe as far away from your house as possible

Why do you want to do this? :confused: And where do you live? This sounds like something you'd see in a 3rd world country. Just go out and buy a small diesel generator if you need that capability.

Yeah, but what's the fun in that? ;)

It is not that easy to run WVO with new injection type of generator. You need a start it with diesel and switch to WVO and vice versa to turn it off. 240D engine is bullet proof and can take all kind of abuses. In any event, I contemplate it also as the engine is there for the taking. A diesel generator would cause $500+.

As I have said, the simpliest way to do it is to hook up an inverter as the end does not justify the means using a generator head.

I think you are thinking the 616 is a little more tough than it is....if you run it 24/7 on veg oil, I'd give it maaaybe 4 months before it starts having major issues. Think of how many hours of run time that is per month. 616's are not industrial grade generator engines. You'd be running it over 740 hours a month at a heavy load (probably close to 2 years worth of run time if in a car), and it would need an oil change almost monthly with a good oil. That would get expensive pretty quick. Plus, where on earth are you obtaining and transporting 1000+ gallons of veg oil a month to run this setup? :eek:

Generators
 

Running at 1800 rpm would be vastly perferable to 3600. Regardless of efficiencies the engine would last much longer and be a whole lot quieter. The average house could run quite nicely on 10KW or for that matter 5KW if you have natural gas heat and hot water. A 240D engine would be more than sufficient to run a house however the engine would have to be governed tightly to maintain frequency control. A large inverter system would cost quite a bit since you would need big batteries as well. The batteries need to be charged by a big alternator which would also cost quite a bit. The stock alternator is capable of putting out maybe 80 amps at 12V (80 x 12= 960W)

A 200-250A 12 or 24V alternator charging a bank of batteries with a 5-10,000 watt power inverter would probably work as well.....but it would still be expensive and inefficient, and probably a lot less reliable than grid power. And then there's still that issue of governing the engine around 1800rpm and the massive fuel use.

That would be quite a task to obtain and filter enough oil to keep it going all the time.

While it seems like a cool project, I think if you consider just the monthly fuel cost you will find it is much more economical to just buy power from the power company.

If the engine burns 1.5 gallons per hour you will need just over 1000 gallons of fuel per month. Unless you have a free source of that much fuel, we are talking a minimum of $2500 in fuel costs monthly. That's more than twice what I pay the power company for a year!

My monthly electric bill averages only about $38. :D Even if the fuel was free it wouldn't justify such a system!

Members here are getting excited on generating electric power and seems to think money is no object. A 5-10K watt inverter at 12V or 24V input?, if it does exist then it will be so expensive that you can forget the whole idea. it is drawing 200-400Amp.:rolleyes:

There is no cost benefits unless you can keep the project costs under $500. If you run the car at idle and just go out and buy a 1.5kw inverter for $150 then you have a prayer to recoup your money and have some fun. The other issue is that if you manage to produce 1KW from the car then you may be able to keep your electricity bill at the lowest tier of tariff.

I am an engineer and I contemplated it myself but I came to the conclusion that it is very difficult to be off the grid and be self sufficient on generator for a household. You have to run on WVO to be viable as you may as well pay the electricity company if you use diesel. If you have $30K to spare then you can put in a solar tie-grid system but that only buy you 2-2.5KW system.

Popular Science
 

I remember a really long time ago reading a Popular Science magazine
article about this very thing. They did it with a gasser V8. They called
it Co-Generation. They had the house set up with slab heating and ran
the engine coolant through the pipes. They used a heat exchanger to capture exhaust heat, and IIRC used a heatpump somehow in the mix.
It ran on natural gas and for the day (70's??) it seemed very high tech
and pretty efficient for it's day.

Back in to 60`s when I was in High School, (got out in 62) I was in the FFA. I subscribed to a magizine called Farm journal.

they ran a article on a Hog Farm operation where they washed down the hog pens into a huge septic tank. They used the Methane Gass to run the generators to operate the farm.

So you guys on a septic tank, you are golden. Think I`ll have another plate of Beans :D.

Charlie

On grid or off? Neighbors, yes or no? Federal incentives are 30% of solar projects, state incentives vary by state. In new york, you would pay about 1/4-1/3 up front cost of an on-grid solar project in the over 4kW. Approximate up front cost 5-6$/watt, before incentives. Solar panels also carry a 30 year warranty, I'm told, longer than a furnace or a 616 on a steady diet of anything.

My Bro-n-law has a backup generator powered by a 90HP VW tdi. I've never seen it, only heard about it. It's mounted on a movable construction site generator complete with wheels and license plates. He can take it to his Cabin in the San Juan Islands, park it in his basement, however, my sister forbids him to run it in there anymore. (Their house was originally built with a 1 car garage in the basement, so it's easy to get it in and out.) As I am editing it has also hit me that his original set up, with the generator running in the basement would heat the house, because the radiator exhausts right into the basement. The main problems were, the diesel exhaust odor could never be completely eliminated, nor enough of the noise for sleeping.

I have no idea how many KW it produces, but he can power his house, workshop and the neighbors house with it, when the power goes out. Not set up to scavenge heat though. Usually he runs it in the driveway. It's moderately noisy, but a lot quieter than it was with the original diesel engine.

I mention it because it does sound like a good idea, but the TDI is a much quieter engine in the first place. VW actually makes a version for such applications, but my Bro in law uses one from a 1997 Jetta, because it was available cheap. The TDI works well because it produces so much torque down low in the rpm band, they're also relatively reliable for a relatively hi-tech engine design.

I love the idea of scavenging the heat for heating the house. For an off the grid cabin, it would work great. One of my peeves is that generating your own electricity is relatively expensive. It would heat the cabin a lot faster than the wood stove, and you're using heat you've already paid for.

The more I think if it, the better I like the idea. It would work great with a 240D engine as well, it's just that a smaller displacement engine with more efficient combustion would be more economical to operate. An old 200D might work too, but hard to find in North America. I'm not sure how many Btu's could be scavenged from a 240D, but I know mine sure keeps the car warm!

Using a trailer mounted work-site generator, but with a blown engine, like my Bro in Law did might make sense for others too.

I've contemplated living off the grid, because there are a couple of areas of the country where you can get really nice lots, cheaply, because they have no electric or phone service.

Thanks for the replies guys and gals. This is just an idea at this point and I may never get to do it. I have the engine, just have to come up with the other "parts" and time. It will be an experiment and to gain experience on CHP.

Its easily possible to live off the grid, it all depends how efficient you can make your household and what methods you use to power it. A combination of solar/wind/diesel generator + a big bank of batteries would result in a very efficient system. Probably not cheap to implement, but it would work. If a household is really frugal, you could get by with very little power at all. I consider myself pretty frugal, I only average 260 kw/hours a month.....and that is with leaving my computer on most of the time. If I dropped that, I'd save another 40-50kw/hours. Its relatively easy to produce a few hundred kw/hours a month via solar/wind/diesel.

An outfit by the name of Marathon used to make, and may still make, a total energy unit powered by a water cooled Briggs & Stratton engine designed to run on natural gas. It generates electricity through an inverter and battery bank, and waste heat is used for domestic heating. This is where the economy comes from- it also heats your house. Life expectancy was 40,000 hours with a once per year service interval.