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Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/10/2010 7:10 PM

Why don't internal combustion engine manufacturers recycle some of the waste heat from the engine? Typically, about 70% of the energy liberated on burning gasoline is lost through the exhaust and the cooling systems, in approximately equal measures. Trying to capture this energy is not usually practical, except in the case of the turbocharger, which is comparatively small and light for the returns it gives. I realize that feeding an engine with a hot air/fuel mixture would play hell with the volumetric efficiency, but so what? Feeding preheated air into an engine must surely raise the overall efficiency. Instead of having a 2-liter engine producing 120 bhp, we might land up with, say, a 4-liter engine producing the same power, but using less fuel. The bigger engine need not weigh that much more since it is less stressed. It is common practice in electricity power stations to use waste heat to preheat the air for combustion (and the feedwater), so why not for IC engines?

Older engines I remember frequently had a shroud around the exhaust pipe with a ducting to the carburetor, but I think this was to avoid carburetor icing in a cold engine, not an energy conserving measure.

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#1

Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/10/2010 7:53 PM

Increasing the temperature of the fuel/air charge reduces the density, and thus reduces the amount of energy that can be extracted. For efficiency, it is better to reduce the temperature of the charge and increase the density, hence intercoolers, etc. It would be great to be able to make use of the waste heat, but I don't know how, and I wait with bated breath.

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#2
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/10/2010 9:14 PM

The old VW Bugs used the heat from the exhaust to heat the cabin via heat exchangers. That's the best example of making good use of exhaust heat.

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#43
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/12/2010 7:33 AM

In South Africa the cars interior needs cooling most of the year. Caravan fridges has no compressor motor and works on the heat of a flame or electric heater element. Exhaust gas heat could also be used to make such an air conditioner work.

When not needed to cool the inside of the car, it could help to cool the diesel engines intercooler!

This could add up to a feul saving of at least 10% for a car with a small engine. Car manufacturers must have had a look at this before.......if not, they can send me the tjek for my "invention"!!!!!!!!!

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#44
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/12/2010 8:21 AM

I'm sure they will immediately send you the full value of your 'invention'!

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#47
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/12/2010 9:21 AM

There are a number of articles available on the internet regarding the use of engine waste heat to drive an air conditioning system, using the absorption cycle. One I read was a thesis by a PhD student at the Uni of Mississippi. Can't find it know. As far as I remember, as long as a heat source of 120F, or more was available, it was viable. Seems to be an excellent use of waste heat, but at the expense of extra weight and cost over the existing compression cycle system.

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#88
In reply to #47

Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/13/2010 8:08 AM

Hello energyconversion:

Fully agree, however vangard technology now employing Co2- R744. Cryogenic cooling using a heat pump creates a lower than needed temperature. Then absorbs heat first stage of heat pump with secondary heat input the exhaust.

Cheers Peter

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#65
In reply to #43

Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/12/2010 4:22 PM

I do not understan how can this be possible to generate Cool air from heat of a flame or exhaust gas heat could also be use to make an air conditioner??

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#68
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/12/2010 4:56 PM

It is possible - but- you need about 10 times capacity of a household absorption refrigerator and the absorption process pull down time is far longer - so for trips less that an hour, it might get cool after you arrived.

Nothing wrong 'technically' - just totally inappropriate technology for the application.

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#77
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/13/2010 3:14 AM

Hello 34point5

Cant agree gas fridge workings are quite small, the rest is quite big.

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#79
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/13/2010 4:35 AM

Hello Das,

I don't mind if you can't agree on the size facet.

Now all that's to be also wrong, are the mass flow ~ Watts x time, and where/how it all fits.

I await

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#80
In reply to #79

Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/13/2010 4:46 AM

Hello 34point5

I know my limits.

Cheers Peter

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#69
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/12/2010 5:27 PM
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#71
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/12/2010 6:25 PM

I already provided a link to an explanation http://cr4.globalspec.com/comment/625537/Re-Why-Don-t-Internal-Combustion-Manufacturers-Recycle-Some-of-the-Waste-Heat

predating jurie's post by some 5 hours, entitling me to the potential royalties :)

seriously not an original concept

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#78
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/13/2010 3:40 AM

Look it up on Wikipedia......there is a good explanation under Electrolux.

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#62
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/12/2010 2:14 PM

The Citroen 2CV did exactly the same.

In fact I am sure that any aircooled car has only this option for heating, not that there are many air cooled cars nowadays......

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#89
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/13/2010 9:09 AM

<...not that there are many air cooled cars nowadays...>

Er, aren't all cars air cooled? After all, most have a heat exchanger to cool the heat transfer fluid circulating through the engine block.

Those that don't rely on air passing cooling fins on the cylinder block.

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#97
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/13/2010 1:21 PM

Details. Details.

An air cooled engine is generally accepted to be one that does not use water to transfer the heat to a heat exchanger or radiator. Typically the transfer is direct through fins on the block and cylinders.

Generally an engine the does use water and a radiator is considered water cooled.

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#103
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/13/2010 3:46 PM

Funny.....

I was meaning without water as a primary cooling agent......

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#106
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/13/2010 5:47 PM

VW would heat your toes, and the lower corner of the windshield !

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#132
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/14/2010 11:21 PM

The cabin heaters on the air cooled VWs never seemed to work any harder than my lazy, unemployed son in law.

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#135
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/15/2010 5:42 AM

Then the "flaps" were not correctly adjusted....or better said, the wire cables/mechanism for the flaps....

A correctly set up system (rarely seen though!) will supply really hot air when needed, so hot that you cannot keep your feet near the ouitlets for long!!

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#146
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/15/2010 10:32 PM

I don't doubt that they did get warm when they were correct. It just seemed that there were not too many that had not been left un-connected, miss-adjusted, or just plain butchered when I was working in the automotive service field in N.Y.

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#147
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/16/2010 3:37 AM

Your statement is sadly exactly true for probably at least 80% of the cars......most people seem to not have a clue what to do to get the flaps adjusted correctly........

It was EXACTLY the same with 2 CVs.....even the Citroen mechanics made a dog's ear of the adjustment.

I once read the works manual and it was right but not well written.....you had to know what to do, just to understand the F*****G manual.....

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#148
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/16/2010 9:51 AM

I once read the works manual and it was right but not well written.....you had to know what to do, just to understand the F*****G manual.....

We are to be reading the manual it is so good, yes? Are your trouble being, it is to say, the Francais are not your language so good for you to understand? Pleased I am to make gooder translation:

"It is so good to making the knob to hot is making the car to hot, no? Then is to check making knob to cold is to make car being cold, yes? Apres adjudication, be true that all screws have good security. (Bien notez: for the lubrication de le cables, parque le 2CV near any DS21 overnight. Oil hydraulique leakage from DS21 will find way to 2CV, in jusque le right amount.)"

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#149
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/16/2010 10:00 AM

Loved it!

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#150
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/16/2010 2:51 PM

I almost understood all of that (being french and all...)

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#136
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/15/2010 5:52 AM

With Beatles there was an inherent danger in this system of getting carbon monoxide into the cabin if even a very tiny leak from the exhaust manifold developed. For short journeys one might survive the exposure but longer ones??? It was only used because the engine had no cooling jacket to extract the heat from. The oil cooler might have been a safer source of heat! However, the cooling system couldn't freeze up and was much quicker to warm up than a water cooled engine heater so was not without merit - as I found in a relative's Beatle in the winter of '84 when the Baltic Sea was hard frozen all around the islands of Denmark!

The basic point is that conventional internal combustion engines produce far more heat than most cabins need to keep warm so will always be venting it somewhere. It would be really nice to harness it without shooting up inefficiency by carrying extra weight or using engine power to drive pumps etcetera.

The best way of doing that might turn out to be by using electric vehicles that run, indirectly, off electricity generated by windmills or in power stations where the efficiency is maximised already.

And surely the range/battery re-charging problem could be improved by fitting power pick up strips in the roads, particularly on hills or at queing points like traffic lights and in parking lots? A sort of Scalextric system in reverse? Vehicles could carry meters that communicated with roadside equipment to charge the user (like aviation transponders).

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#137
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/15/2010 7:26 AM

Right! Be sure to tell the power company to only send you electrons generated by one of those sources you mentioned.

But you would buy green power so you can tell your buddies about how good you are?

Buying green power from the utility today is one step past silly as far as I can see.

Non-contact charging for anything more that a very small battery is not yet close. The payment system you mentioned? What have you been smoking?

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#139
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/15/2010 9:31 AM

Bit harsh Russ.

I think I've seen the idea - ah yes here it is;

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#141
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/15/2010 10:36 AM

Can't see a 3rd rail or overhead wires servicing passenger cars - not at all.

The non-contact thingies they are working on now and actually have for low power devices are a long way from supplying something like a car on a highway.

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#142
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/15/2010 12:22 PM

Yep - was tongue in cheek - am aware of 'air cored transformers' too. Bloody inefficient but handy for rechargeable electric tooth brushes, dildo's and stuff that is better sealed against wetness, or hard wiring is inconvenient, like implants.

Same old deal

"appropriate technology".

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#138
In reply to #136

Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/15/2010 7:44 AM

Much has been said on not improving something which is over 100 years old. The only thing to do is chuck it. However waste heat is waste heat no matter what the engine. The answers so far appear to centre on leaving the relic of long ago as it is and work out how not to waste heat. Modern times usualy generate modern thinking. Perhaps more of that shall appear here. Lets rethink the engine and not waste heat. Engine manufacturers dont develop engines they just fiddle with old ones.

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#140
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/15/2010 9:41 AM

And yet that 'fiddling' has resulted in near quadrupled mpg over that 100 years, because it's not just about "combustion efficiency" but the total package efficiency.

So let's think total package? - not just the engine? - and not just it's waste heat?

Do that, and you can grasp "Why don't internal combustion manufacturers recycle some of the waste heat?"

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#145
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/15/2010 4:36 PM

May I correct/help your spelling a bit:-

Beatles = a popgbroup from Liverpool, UK. Popular (still!) mainly in the 60's and 70's....

Beetles = A name given to a particular type of car produced by Volkswagon for many, many years.....and some insects!!

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#4
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/10/2010 10:16 PM

Well that's why I said "play hell with the volumetric efficiency." I am talking about the thermal efficiency. High volumetric efficiency and intercoolers are appropriate if you want to extract the most amount of power from a given engine size, as for instance in racing engines, limited to a certain swept volume. I am suggesting that larger engines, running at higher thermal efficiency due to the use of waste heat, might give us more m.p.g. for road going vehicles.

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#29
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/11/2010 10:56 PM

"Increasing the temperature of the fuel/air charge reduces the density, and thus reduces the amount of energy that can be extracted."

Reducing charge density lowers volumetric efficiency, which lowers the power output. Thermal efficiency, however, is increased due to regeneration. Even that comes at a price, though - preheated charges are more prone to detonation in gasoline engines. In diesels, combustion is improved, but their already low volumetric efficiency (due to the need for excess air) is further penalized.

Back in the old days, there were plans to use evaporative cooling of the engine core and then superheat the resulting steam using the exhaust manifold. As cars got smaller and their engine compartments began to resemble shoeboxes, that scheme was abandoned. It might still work for heavy road-haulers, but the sales volume might not justify the development costs.

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#157
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

12/21/2010 4:00 PM

So many other things have been miniaturized, so why can't a system like this be shoehorned into a modern car? I would imagine because for a long time there was plenty of cheap fuel and this was deemed an unnecessary complication. Not so unnecessary today.

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#158
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

12/21/2010 5:56 PM

Laws of physics. So much heat transfer area is required. Increasing heat transfer area while keeping volume low causes an increase in exhaust back-pressure, which reduces engine efficiency. You gain at one end, and lose at the other. No win.

Quite aside from that, bottoming cycles and other heat-recovery methods are expensive, and the first cost of a family car is a major influence on the buyer's decision. Fleet operators tend to consider lifecycle costs, which are heavily influenced by fuel use, so there's hope of compound cycles winning in that area. There too, however, increased maintenance costs have to be taken into account.

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#3

Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/10/2010 9:14 PM

This may sound familiar, and is a pretty good explanation.

"It's the engineers dream to use the waste from an engine and do something useful with it. The internal combustion engine grabs the "easy bit" at high temperature, converts it to rotary motion and throws the rest away. Doing something useful with the waste heat can be done, but at the expense of a heavy and expensive appartus such as a Stirling engine or Rankine cycle engine. I was recently looking at the results achieved by Sataima University, Japan. They fed the exhaust gases from a 3.5 kW gasoline engine into a custom designed Stirling engine but only managed to get 3% of the exhaust gas energy out of it. Pretty discouraging!

"Seems to me that a turbocharger is about the only reasonably small, light and cheap way to extract some of the exhaust energy."

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#6
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/10/2010 10:40 PM

Yes, I wrote that earlier (well remembered). Using a separate system to reclaim the waste heat is just not worthwhile. But what I am wondering is whether there is anything to be gained by using an oversize, "lazy" engine, recycling some of its' own waste heat to the induction side. Forget high power/weight ratio, forget power/volume ratio - go for best fuel consumption.

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#102
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Re: Why don’t internal combustion manufacturers recycle some of the waste heat ?

09/13/2010 3:33 PM

I seem to remember a couple of heat recovery schemes applied to heavy commercial vehicles. I believe one application used a turbocharger like device to recover energy and another used a thermal electric film to generate electricity. As you said though the recovered energy was very minimal. I did find a link that had some interesting information in it.

http://www.sae.org/mags/tbe/7472

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#5

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/10/2010 10:20 PM

From what I understand, part of the problem is the wide range of power and RPMs over which the engine must operate. One of the advantages of a gasoline-electric hybrid is that the gas engine can be optimized to run very efficiently at a set RPM and at a set power level. I imagine there are websites that discuss the efficiency of this arrangement and they may mention the energy savings in terms of a reduction in waste heat.

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#7

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/10/2010 11:05 PM

To some extent, in the winter waste heat from the jacket water is run to keep the passengers warm. This may seem trivial, but when it is -40 outside it is nice to have some warmth from the engine.

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#8

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/10/2010 11:55 PM

And yes there is a lot of waste energy. Cycling it back into the engine starts a vicious circle of temperature build ups, ending with melting crankshaft bearings, aluminum parts, burning oil and plastics, hotter cars.

Tests are done with ceramic motors but still pose a lot of problems with all kinds of cracks.

If this works out well, combination sources - combustion and steam cycles combinations could be something towards your ideology.

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#25
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 3:04 PM

dvmdc says: "Cycling it back into the engine starts a vicious circle of temperature build ups, ending with melting crankshaft bearings, aluminum parts, burning oil and plastics, hotter cars."

I don't know why you take such a negative view of this. During the great "Turbocharged Era" in Formula 1 from 1977-1988, 1.5 liter engines were achieving 1,300 bhp in practice and routinely ran at 1,000 bhp during a 2 hour race. Ferrari even claimed 1,500 bhp for brief periods on the dynamometer (1,000 bhp/liter!). Later the FIA limited the boost pressure, but pressures up to 5.5 atmospheres had been used briefly. If you assume an efficiency of 30% (a bit higher than normal because of the turbocharging), at 1,300 bhp, the total heat released by the engine, according to my calculation, is about 2.3 megawatts - enough to heat Westminster Cathedral on a cold day, yet most cars finished their races without their engines melting. Of course, a 150-200 mph breeze helps the cooling enormously.

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#26
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 10:22 PM

I'm having a realistic view in it. With turbo you supply the engine with "cooler" air than what your exhaust is generating. The turbo has to be cooled to have it last too.

------

Here is my positive view if it may help: Instead of driving, a process that can take a lot of your life time: You can use to heat to heat water while driving. You can sell it on the way or have a bath or shower installed in your car.

What I am saying is, that beside making lots of GSM phone calls, you can shave, take a bath, sauna or turkish bath. I don't know if it is allowed where you live. In the US a poor women got arrested while mast***ating in a car with too dark tinted windows.

Freedom, restriction?

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#27
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 10:26 PM
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#49
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 9:31 AM

Oh well, at least she tried to remain invisible.

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#50
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 9:39 AM

While driving or parked???? I hope they let the poor woman finish what she started before arresting her

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#53
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 10:12 AM

"If you assume an efficiency of 30% (a bit higher than normal because of the turbocharging), at 1,300 bhp, the total heat released by the engine, according to my calculation, is about 2.3 megawatts - enough to heat Westminster Cathedral on a cold day, yet most cars finished their races without their engines melting. Of course, a 150-200 mph breeze helps the cooling enormously."

So does the extremely rich mixture that a race car typically burns. I thought the objective was increased efficiency.

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#91
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/13/2010 10:05 AM

Also keep in mind that the engines revved to 19,000+ RPM to achieve that level of power output. You can make any size engine put out almost any amount of power if you could increase the RPM enough. We know that there are technical and physical challenges that limit practical RPM values. You could also look at two stroke engines and variations of them. A power stroke every revolution versus 2 revolutions will make more power but usually at the cost of fuel efficiency. ( Each 180 degree of crank rotation is a stroke).

The goal is to recover not only thermal energy but exhaust gas pressure. A turbo makes use of the residual exhaust gas pressure while the temperature of the exhaust gas remains fairly constant. A turbo can not really be considered a thermal energy recovery device. Desalination plants now use a very similar technology to recover pressure from the high salinity waste stream to help drive the pumps.

Steam engines have used a stepped expansion chamber approach to recover as much pressure from the steam as possible rather than send wasted steam pressure out of the exhaust. Each drop in pressure makes it harder and harder to recover energy. This is also easier at lower RPMs of a steam engine.

I have often thought of various ways to recover heat and pressure from an IC engines exhaust. I do have a few ideas that I have incorporated into some concept engines I designed. I have not been lucky enough to build any of them and they most likely work better on paper than in actuality. It is fun to work on though. The idea is to step the expansion into existing areas of the current engine setup. I wanted to use a four stroke engine like a 2 stroke but use the space under the piston as a secondary expansion recovery cylinder for the exhaust gas. This would require a two cylinder approach because you can not have the pistons compressing the gas that you are trying to recover energy from. One cylinder during the end of the exhaust stroke would open a valve so exhaust pressure could travel under its piston so the cylinder is static, no compression or expansion. Now it also opens a port to allow the gas to travel under the second piston that will than work to recover the pressure that is normally expelled out of the exhaust. You could make use of the under side of the piston for either increased displacement and power or for increased efficiency. there are many ways that this could be configured and also in combination with a turbo at higher RPMs.

The other idea is to use water injection into a secondary turbo only during high temperature conditions. This may actually lower the pressure unless you have so much residual heat that you can convert it into steam pressure. I have not actually run any calculations on this idea so it could be completely useless. Water injection into the turbo is used to keep them cool but I don't think it has been use to increase output by producing steam pressure.

the harrier jet uses water injection to keep the jet engines from overheating during full power vertical takeoffs and hovering. They were limited to about 60 seconds because the water runs out very quickly. I don know if the newer generation Harriers still use this system for keeping the turbine blades cool.

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#114
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/13/2010 11:03 PM

This is slightly off topic.. Boeing fitted methanol/water injected turbo-jet engines to early model B707's / KC135's & B52's {Pratt & Whitney JT3P.& J57} Movies of the day show very dirty efflux / exhaust from these engines. And yes, there is a limit to this sort of power boost, due to the short supply of water.

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#115
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/13/2010 11:38 PM

Further to my 'Boeing" post..got the engine models wrong. C135's & KC135's initially used P&W J57 turbo-jets. When I checked my reference, I thought they were Westinghouse build numbers, but was on the wrong page..{aren't some of us?} J57's were changed out for less maintenance intensive, quieter and more fuel efficient CFM56 (F108-CF-100).

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#116
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/14/2010 12:15 AM

OT, but I found it interesting that turbo-jets showed a boost in power after being sand blasted by Icelandic volcanic ash. Sorry can't put my finger on the link, but seems all is not yet 'fully developed' in the art.

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#133
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/15/2010 12:43 AM

Ah but don't forget the 'Gulungung glider' [1970's??]. A British Airways B747 w RR524 engines on way from Kuala Lumpur Malaysia (?) to Perth Australia. Flew through an ash cloud which stalled ALL four engines by coating the blades in volcanic particulate. Eventually got all engines re-started, plane landed at Jakarta airport looking rather sand blasted. Engines sent to England for boroscopic and strip down investigation - summarised as 'not a good idea'

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#134
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/15/2010 1:02 AM

I get the feeling if I said "there is something to be learned from how they work in rain" you would answer "but don't forget they don't work under water".

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#75
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/13/2010 1:08 AM

the engines you describe would have been stripped and rebuilt after every race, Hardly cost effective.

in real life you need a good reliable energy source that will do the job it was designed for, not somthing that needs a bank of engineers monitoring its every move via telemetry with a highly qualified driver at the helm.

and what dvmdc is i think refeering to is the fact that you need to get rid of the heat produced in an ic engine so feeding it back into the inlet would mean the engine had hot air inside it to start with.

may i suggest looking at this to start you off

http://www.google.co.uk/search?q=how+does+the+internal+combustion+engine+work&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&amp;ie=&oe=&rlz=1I7GGLT_en&redir_esc=&ei=ibGNTOzgBNO7jAeg96COBg

CR4 Admin: Personal attack removed.

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#76
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/13/2010 1:42 AM

As Peter pointed out - with autos equipment and systems are expected to operate forever with little or no maintenance.

In industry you normally have back up equipment and a maintenance staff to take care of problems - big and small.

Two very different worlds!

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#92
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/13/2010 11:11 AM

CR4 Admin: Removed reference to content edited out of parent post.

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#112
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/13/2010 10:44 PM

I'm under the impression that many / most / all F1 engines are built / re-built for EACH race. So whilst it may be great to get 1300BHP from a 2 litre IC engine, it's hardly practical to consider for 'everday use' - but wouldn't the police like it..money on a stick!

To change part of the thread..what SHOULD be considered is greater efficiency of the IC engine. Waste heat is generated in every conversion of energy, including us !

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#121
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/14/2010 8:22 AM

From my head, modern F1 motors are only around 900 BHP depending upon the manufacturer/constructror, they probably range from 800 to almost 1000 BHP.

Current regs are a V-8 engine, 2.4 liters, normally aspirated, limited to 19,000rpm, weighing no less than 95kg. Cylinders must have 4 valves, single spark plug and single injector, and variable valve timing is not allowed. Cylinder blocks must be aluminum alloy, crankshaft and cams iron alloy, and pistons aluminum alloy. Composites are not allowed in the engine structural elements. The starter system is not part of the engine system- external removable starters are required. Engines may have anti stall devices, but must shut down within ten seconds after an accident. regs change, but these seem to be current, keith ref:

http://www.formula1.com/inside_f1/rules_and_regulations/technical_regulations/

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#126
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/14/2010 11:31 AM

Higher efficiency comes from higher compression ratios which raise the high point temperature in the basic 2nd law calculation of theoretical maximum efficiency. IIRC about 30 years ago compression ratios were reduced as the only available answer to the NOX pollution problem. Since then technology has produced the needed answers to control these pollutants and compression ratios are starting to go up to the point where even everyday drivers with barely a whiff of "high performance" in their specs are running higher compression to improve mileage. (example: the BMW Mini).

The interesting factor here is that the spread between the cost of regular and premium gas is based primarily on refining costs whereas the overall cost of gasoline is based on the cost of the crude oil. Thus the higher the price per gallon the more the incentive to spend the small extra for premium gas which increases mileage and results in net cost savings to the retail customer.

I think the real progress in the engine efficiency direction will come from the "dieselization" of all internal combustion engines via advances in combustion control technology and engine materials. We could talk also about other aspects of efficiency improvements in the automobile transportation system. There's a lot of interesting stuff at the concept and R&D level. But that's getting OT and best left to another topic.

Ed Weldon

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#9

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 6:24 AM

I believe about the only practical thing to do regarding the wasted heat is continued advancements with engine performance in particular the turbo charger. If we could increase its performance, we could then in effect increase the engines performance.

In this way we could possibly go from a 2 liter engine to say possibly a 1.5 liter producing the same output. However still producing high levels of waist heat as this is needed for the turbo.

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#10
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 6:41 AM

Yes, I tend to agree. I can see what energyconversion is driving at, with the 'big, lazy engine' idea, but I think the amount of energy recovered, if any, would be very small, and would probably be lost again through the compromises that would need to be made to recover it in the first place, ie you might be making a less efficient engine in order to recover a little bit of energy from the waste heat.

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#11

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 7:56 AM

I believe someone is trying to capture some of that lost heat via twin turbos.

What are your thoughts on this?

h

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#12
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 8:32 AM

Problem is that currently most twin turbo applications are running parallel, in most cases they just look impressive but you do not really gain any more than if you have installed one properly sized unit.

For instance a V type engine is a normal candidate for this idea, so right exhaust manifold feeds one turbo, and left another. Once you weigh in all the pro's and con's, you would be much better to have one very efficient turbo rather than a show piece of plumbing mounted under the hood.

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#14
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 10:29 AM

Just as well you said most. I thought I had read somewhere recently of a car with a two-stage turbo. The following page from Borg Warner explains it quite well.

http://www.turbos.bwauto.com/products/r2s.aspx

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#15
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 10:59 AM

Hey sitting here pondering with my assistant J.D. and think you could use the waste heat to make coffee or tea while motoring down the road???

Na but seriously, the two stage, single turbo would be the way to go. Couple this with a very well thought out injection system and there you go!

What I was referring to previously was the cars you see in the magazines with so many chrome tubes under the hood that you cant even see the basic engine.

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#117
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/14/2010 1:03 AM

Hey Tim, I agree, sort of. My example-ish would be when I mated a Holset Turbine housing and impeller with the desired A/R ratio and a Schweitzer Compressor housing and impeller with the Trim and A/R ratios I couldn't find with any other manufacture to meet my requirements. Being a machinist has it's advantages.

I also built an adjustable device contained in the base of the turbine housing that is configured on what fuel ratios, expected rpm and exhaust pressures and temperature ranges all to provide a more optimum range of efficiency in the ICE's build profile. Specific to intended use of course.

I hate "turbo lag" and thus these improvements resulted in hardly noticeable lag at lower rpm ranges. With my specific engines operating characteristics it resulted in quicker spool up without loosing mid and top end gains. I feel there are incremental ways to scavenge wasted heat energy for the conversion characteristics through other elements or devices. Not what this turbo is doing specifically but the overall design of it and it's specific application provides a little higher/wider output gain.

I've also done lots of chassis and engine dyno testing utilizing different means of introducing different temperatures of steam just for kicks to find some pretty interesting results. Timing of and temperatures are everything to get a noticeable gain. Nothing on a BSHP dynometer though.

BTW I've cooked much food in my engine compartment at time, just to see!

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#119
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/14/2010 5:16 AM

Cool project.... I bet it was an exhaust nightmare

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#13
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 10:25 AM

I assume you must mean 2 turbochargers in series - 1 high pressure, 1 low pressure - in order to extract the most exhaust energy. I haven't heard of this, but it makes sense.

"Twin turbos" normally means 1 turbo per cylinder bank (as pointed out by Tim in Mexico) for V-engines.

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#16

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 11:33 AM

I've got a question that hopefully someone smarter than me might be able to explain.

Rather than redirecting the heat back into the engine, is there a way to generate electricity from heat, besides steam generation?

I'm thinking, if that were possible, maybe the alternator could be eliminated, using waste heat to charge battery would increase efficiency.

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#17
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 11:55 AM
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#18
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 11:57 AM

There is - the "Seebeck Effect," - otherwise known as Thermoelectric Generators:

"Scientists at Ohio State University have taken a thermoelectric material that's been used for decades to power deep-space probes, and worked out how to double its efficiency. That's good news: thermoelectrics convert heat directly into electrical energy. By catching exhaust heat, the new material may allow car alternators to be replaced... and that'll push up the efficiency of car engines. The team doped lead telluride with tiny amounts of thallium, which adjusts the crystal structure and increases its heat-electricity conversion efficiency from around 6% to over 10%. Even better, since engineers have years of experience of working with lead telluride, it should be easy to commercialize the product. Environmentalists will have to be pleased, and relax about the high toxicity of thallium, though."

The big snag is the low efficiency. Hard to get excited about 10%, let alone the current 6%.

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#19
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 12:22 PM

That's what I was talking about. The efficiency isn't great, but it's a start.

I had remembered reading about these several years ago, http://edge.rit.edu/content/P10451/public/Thermoelectric%20power%20generation%20from%20biomass%20cook%20stoves%20Champier%20et%20al, but no where near enough power to charge a battery.

This doesn't directly apply to your post, but I thought the concept was really cool.

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#20
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 12:37 PM

Also known as the Peltier Effect. There are Peltier devices kicking about already.

http://www.peltier-info.com/

Alternatively - wrap your salmon in foil (works also for trout, mackerel, etc) and tuck it in next to the exhaust manifold. By the time you get home it should be done

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#21
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 1:12 PM

Thanks for the post, good reading. I'll have to get back to it though, my wife thinks I should be working in the yard on weekends, I have to get out there and act busy.

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#101
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/13/2010 2:48 PM

Put a computer out in you milk house, barn, shed, garage, out building, ect. Worked out good for me.

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#104
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/13/2010 3:55 PM

Good idea, but one of the things I have to do, is clean all of the accumulated crap out of my shop to make it functional again. I can't even fit a computer in there right now.

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#22
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 2:31 PM

Be extra careful with the mackerel - it's very oily and could catch fire, making your energy savings a bit irrelevant.

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#23
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 2:38 PM

How am I expected to cook for a family of six with four piddly little cylinders? Must tell wife I NEED the V6, if not V*.

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#24
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 2:54 PM

I'm on break. I've only used this method with hot dogs and left over burritos. It works well. Thanks for the tip on the mackerel.

Hey, I bet we could make a little hot box, and direct radiator fluid through it to keep lunch hot. It would be great for people that work out in the field.

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#54
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 11:14 AM
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#109
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Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/13/2010 9:50 PM

Replying to Comment by energyconversion:

When its for free, efficiency does not matter that much any more.

Cheers Peter

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#111
In reply to #109

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/13/2010 10:26 PM

"Free"

Nothing is free Das - but is the only thing that is.

If something is said to be 'free' - it means the speaker is blind to the whole system cost.

10% efficiency means the infrastructure is 90% "waste of effort".

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#113
In reply to #111

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/13/2010 10:54 PM

Replying to Comment by 34point5:

Some only pay for infrastructure once! and generaly for another purpose. Any thing extra is free!

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#28

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 10:39 PM

Thermodynamics, it's not just a fancy word, it's the answer.

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#31
In reply to #28

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 11:20 PM

Review the second law of thermodynamics. It explains why diesel cycle engines have inherently better efficiency than otto cycle engines. Further it explains the reasons behind the higher theoretical efficiency of turbocharged engines over naturally aspirated engines and why the efficiency increase does not exist in mechanically supercharged otto cycle engines.

The "secret" lies in the temperature differences between the stages of the heat cycles. And because these differences in temperature relative to absolute zero are so small when we attempt to use "waste" heat from cooling or exhaust systems the efficiency gains are small. Thus the hardware associated with capturing this heat and converting it to usable energy remains too expensive )and heavy in energy wasting parasitic weight)to pay back in the reasonable life cycle time of the typical passenger automobile.

Ed Weldon

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#55
In reply to #31

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 11:18 AM

so what you're saying is that we need a big block of unobtanium and all our dreams may come true?

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#30

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/11/2010 11:07 PM

Last millenia, in the late '70s, I knew a guy in the far north where people have to plug in their cars at night who was working on a way to store some of the heat to keep the engine warm at night, saving electricity, or for use if no electric outlet was available perhaps. I think he was heating up some kind of substance in tanks with the radiator water, then getting the heat out at night.

You could do this and dump the excess heat into your home when you got home. Driving a pickup or vehicle with room to store the hot substance would be helpful. I'd think you could get a fair amount of heat this way. Just have some quick disconnects to connect when you get home and run hot water to a fan-coil in the house.

When you patent it, send me 10% of the profit - I'll do a printscreen of this post as proof it was me.

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#51
In reply to #30

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 9:50 AM

Volvo developped a heat storage system for cold climate use using waste engine heat. It consisted of a "phase change" material, such as sodium acetate or sodium sulphate solution, that stores the latent of fusion and releases it on cooling. As far as I remember it was only for keeping the inlet manifold warm.

I like your "taking the heat home" idea!

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#32

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 12:00 AM

Some manufactures recycle some waste waste,in ships diesel engines they utilize exhaust heat output from turbocharger to boil water for steam production termed as economiser, modern engines have uncooled turbocharger(s) so the exhaust gas temperature leaving the T/C are higher hence steam energy produced from waste heat boiler(economizer) can drive steam turbine to produce power on board,heating,pumping,etc

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#34
In reply to #32

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 12:31 AM

Uncooled turbochargers? "Maybe" not water cooled, but how do the bearings work? If the oil flows through with some pressure, that is also for cooling too.

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#38
In reply to #34

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 3:34 AM

In most turbo charger on ships they used to have water jackets,modern uncooled don't have,lubrication oil is cooled by circulation through the T/C cooler(s) or in some cases engine oil is supplied to T/C circulate back to the system oil and cooled.In short the T/C with out water jacket are categorised as Un cooled T/C

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#33

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 12:30 AM

Jay Leno has a steam powered car. It is fast and you only have to fill it up with water and fuel. Hundreds of pounds of water plus fuel. Not the most convenient.

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#35

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 1:32 AM

What about a adsorption powered intercooler to increase the charge density? http://en.wikipedia.org/wiki/Absorption_refrigerator

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#36

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 2:03 AM

Why don't internal combustion engine manufacturers recycle some of the waste heat from the engine?

They do. Turbochargers do this (albeit very ineffectively from a fuel efficiency standpoint -- petrol turbos offer no better fuel efficiency than the cars with larger engines with which they compete). BMW and others are working on turbo-powered alternators, and there have been direct heat-to-electricity devices, waste heat powered air conditioning, etc. So far, all these have had minor beneficial effect.

I wouldn't expect an increase in thermodynamic efficiency from preheating intake air. If the goal of running the engine is to elevate the coolant temperature, then the situation would be analogous to the power plant boiler situation.

The exhaust heat ducting in engines was used to improve fuel vaporization in cold engines, so that less mixture enrichment could be used.

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#37

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 3:25 AM

As I remember the auto makers did try this with the turbo charger. the trouble with it was that it shortened engine life.

Sir if you can design a more efficient method of converting energy, you would be rich and famous...

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#39

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 3:56 AM

Is the exhaust temperature high enough (around 1200C?) to use Magnetohydrodynamic (MHD) electricity generation? Inject a little Cesium or Potassium into the exhaust stream, which ionises it, pass the gas by two electrodes, with a magnetic field parallel to the electrodes and perpendicular to the exhaust gas flow. This forms a linear DC generator, with ionised gas as the moving conductor, cutting magnetic lines of force.

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#64
In reply to #39

Re: Why Don’t Internal Combustion Manufacturers Recycle Some of the Waste Heat ?

09/12/2010 3:58 PM

An excellent idea.

Peugeot are to launch a diesel/electric hybrid next summer. If the turbo can produce electricity as per your suggestion and charge the batteries - I am sure it would be the most efficient car on the road. They already claim 74mpg (UK).

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