Wasted heat from combustion engines...

[JimW1949]

The Volvo C30 Electric has an ethanol-fueled heater.
http://www.engadget.com/2011/03/25/volvo-c30-electric-test-drive-video/

For what it's worth, many cars already have auxiliary heaters (i.e. not from engine heat)... just not so much in North America. I think a lot of older air-cooled Volkswagens burned gas as a heat source.

I watched the video, it was very interesting. It would be nice to have a car like that, but the video said that initially they don't plan to sell the cars, just lease them. Leasing the car wouldn't be so bad but for $2,100 per month it is WAY out of my price range. Hopefully all will go well with the leased cars and then they will start selling the cars instead of leasing them. I imagine once they do that the cost will come down and make it more affordable for "regular people".

 

[Merad]

Modern cars are very efficient at burning gas.

IIRC, the maximum possible efficiency of a standard 4 stroke engine is something like 35%. Not what I'd call "very efficient" by any means.

There have been some ideas for improvement - google "six stroke engine" or "M4+2 engine", but for whatever reason (take your pick of legitmate reasons and/or conspiracy theories :awe🙂 they aren't much beyond the basic prototype stage.

 

[pandemonium]

Also, I stumbled across this that's a little more on-topic than all of our tangenting we've been doing lately. Very cool. 😀

You guys didn't like that link? Unless this is an April fool's joke, that'll be the next biggest thing I think. 😛

 

[evilspoons]

You guys didn't like that link? Unless this is an April fool's joke, that'll be the next biggest thing I think. 😛

That sounds very complicated, mechanically. Electric cars are likely to catch on, at least as commuter vehicles in nice climates, since they're so easy to build (minus the battery). I can make an electric motor on my desk with like $2 in parts.

 

[exdeath]

I wouldn't trust a nuclear fission engine. I remember one of the Bikini island test blasts was only supposed to be 4 or 5 megatons and ended up being 13.

Edit: I looked it up. Castle Bravo March 1, 1954 at Bikini Atoll, Marshall Islands, as the first test of Operation Castle. Castle Bravo was the most powerful nuclear device ever detonated by the United States, with a yield of 15 megatons. That yield, far exceeding the expected yield of 4 to 6 megatons, combined with other factors, led to the most significant accidental radiological contamination ever caused by the United States.

That was because they used a tamper (casing) made of fissile material (or one that became fissile under intense fast neutron exposure, eg U-238) that created a third bomb stage. Fission fusion fission aka boosted bomb.

At the time, it was not known that U-238 in the casing would become fuel for a much bigger bomb, because ordinarily it's incapable of fission and considered "inert"

Power reactors for energy don't have these unpredictable characteristics.

 

[Gibsons]

If you want to make a nuclear jet engine, you can, and it has been done, and it does work. You simply use a nuclear fuel to heat the air, instead of fuel.

Yep. Project Pluto. Very neat, if scary, stuff. Potentially a real doomsday weapon, just by flying around.

 

[pandemonium]

That sounds very complicated, mechanically. Electric cars are likely to catch on, at least as commuter vehicles in nice climates, since they're so easy to build (minus the battery). I can make an electric motor on my desk with like $2 in parts.

Actually, not really. Compared to 2 or 4 stroke combustion cycles it's incredibly simple. The design almost allows for self-perpetuated stages of combustion since there are so few mechanical parts. Being as simple as it is, it certainly does make sense (to me at least). The shockwave function is right there for the taking. The only thing difficult, per se, would be the timings. Since we have computer systems available to the common consumer that can compute gigaflops, I don't think that'll be a problem.

I especially liked the fact that this is the entire engine: that cylindrical, rotary engine.

Also, the wave disk engine would basically be a generator (at this point in development anyways), and not a driveshaft directly. Though, I'm sure the design could be tweaked to have more torque, the speeds that this engine would run at would be incredible. Think F1 rotary engines and well beyond. 40k RPM engines, here we come!

Ya, your V12 with twin turbochargers has 950whp @5500RPM? That's nice. My C2 (2 WDE) is pumping out 2500whp @34600 RPM. How ya like me now? Weee---eee-----ee----------e.

I can't wait to have this one and plop it in me Integra. 😀

 

[Ninjahedge]

Strange thing I was thinking of... and I have no clue how they would be able to convert the mechanical energy in some of this.

The simple example would be steel. You get a large hunk of this stuff and heat it, it will expand. You confine this expansion and it will exert a LOT of force. The thing is, because the modulus of elasticity is so high (29,000 KSI) a little expansion gets rid of a lot of force....


But what would happen if you heated this sucker up and had some very precise, but rigid constraining material that would be available to take that small motion and convert it into something that could be used? FxD = work. You get 200,000lbs of force going one inch o deflection, you are getting a HELL of a lot of work compared to some other pressures and expansions....

Go one further. You now have this hot mass of metal... what happens when it cools and you hold the neds trying to prevent it? You get the reverse happening as it transfres the energy back out...


Could you heat the steel up (use it as the collector), let it push something, then cool it with water (going to steam) and use both the energy in the steam along with the contraction of the steel to power more devices?


Last question... Ice is a weird one that does thnigs that a lot of other chemicals do not... How effective would it be to have that mechanical reaction power devices? What about simply applying pressure to ice to let it melt, then remove some of the weight to allow re-freexing and have the remainig weight lifted? Would this work? How could it be gotten to work (harness the cold of high altitudes? radiant dispersiion of heat energy?)

I don't know how practical the ice thing would be, but it seems like thinking differently about what we have may be the only way we get somewhere we can eventually use.....

 

[A5]

Strange thing I was thinking of... and I have no clue how they would be able to convert the mechanical energy in some of this.

The simple example would be steel. You get a large hunk of this stuff and heat it, it will expand. You confine this expansion and it will exert a LOT of force. The thing is, because the modulus of elasticity is so high (29,000 KSI) a little expansion gets rid of a lot of force....


But what would happen if you heated this sucker up and had some very precise, but rigid constraining material that would be available to take that small motion and convert it into something that could be used? FxD = work. You get 200,000lbs of force going one inch o deflection, you are getting a HELL of a lot of work compared to some other pressures and expansions....

Go one further. You now have this hot mass of metal... what happens when it cools and you hold the neds trying to prevent it? You get the reverse happening as it transfres the energy back out...


Could you heat the steel up (use it as the collector), let it push something, then cool it with water (going to steam) and use both the energy in the steam along with the contraction of the steel to power more devices?


Last question... Ice is a weird one that does thnigs that a lot of other chemicals do not... How effective would it be to have that mechanical reaction power devices? What about simply applying pressure to ice to let it melt, then remove some of the weight to allow re-freexing and have the remainig weight lifted? Would this work? How could it be gotten to work (harness the cold of high altitudes? radiant dispersiion of heat energy?)

I don't know how practical the ice thing would be, but it seems like thinking differently about what we have may be the only way we get somewhere we can eventually use.....

Where do you get the heat to heat up the steel? Your rigid material would have be something that has an even higher MoE and then you'd have to find some way for that material to turn the energy into something useful more efficiently than your initial heat source.

As for the shock-wave engine, I'll be more interested if/when they get the 25kW (33.5 HP) version up and running.

 

[pandemonium]

You get 200,000lbs of force going one inch o deflection, you are getting a HELL of a lot of work compared to some other pressures and expansions....

I like the idea, but like A5 said, where's all the energy coming from to heat the steel in the first place? The amount of energy put in to heat it will never equal or exceed the amount that you can get out of it.

It's a good thought to use this principle in more extreme climates though. Adapting to your surroundings instead of modifying your surroundings to adapt to you is always an acceptable course of action.

 

[Fallen Kell]

basically, what you are referring to is "open loop" mode. aka, dummy mode. when the engine is cold, the o2 sensors cannot get accurate readings so the ecu just feeds a rich mixture to the engine to keep it running. degrading engine efficiency wont help it heat up faster though... the only reason they run a rich mixture in open loop mode is because its more reliable to have a mixture too rich over one too lean.

Exactly. A rich mixture will not damage the engine, while a too lean one will. It is also the reason why most cars are set with a slightly rich mixture out of the factory door. As high precision as most modern engines are, they still tweak the fuel mix a little rich just to make certain that there isn't some variance on the O2 sensor reading vs true value.

 

[Abwx]

You miss the point. Heat *is* kinetic energy - it is just the aggregate of a large number of particles with random kinetic energy. It can be converted to ordered kinetic energy (e.g. thrust from a jet, or movement of a piston) but at the cost of only being able to capture a fraction of the energy.

.

I was about to give my view, but this is well expressed in this post.
I will add that since the global movement goes in all direction, a
sizable part of the total kinetic energy is used to....make the bad
directed atoms take the right course, this in the exemple of the
thermic engine.

Indeed, when a car is fully braked, the brake discs get hot,
but if we were to take an immobile car and then heat its
brake discs, it wouldn t move a millimeter.

This has to do with the principle of thermodynamics that
say that entropy can only rise, otherwise, we could
use the sea s water temperature to move sheeps, which is
unfortunately not the case...

 

[DaS Energy]

The injected combustion engine is less costly and has much more power when the process of electric refrigeration is included in its workings.

Modern refrigeration uses recycling Carbon Co2 R744 as its cooling liquid. It has an expansion force of 10,000 bars at 100* Celsius, declining at lesser temperature.
(Diesel force 32 bar at 1,200* Celsius)

Both the electric fridge and the combustion engine rely upon a compression force.

Both the electric fridge and the combustion engine rely upon an expansion force.

Diesel burns at 1,200* Celsius and half that heat may be absorbed by heat cylinders.

To replicate the force of Diesel expansion the heat cylinders need be 50* Celsius and the R744 be 30* Celsius at injector pump.

At commencement of C/E piston power stroke cool liquid R744 is injected into a hot cylinder where the expansion forces of the coolant replaces the forces of combustion.

During the C/E piston compression stroke hot R744 gas is forced into a cooling chamber such like as found in an electric fridge.

 

[DaS Energy]

Hoping this is correct to show picture. Peter 🙂 http://i1225.photobucket.com/albums/ee397/DaSEnergy/DaSHeatEngine.jpg

 

[Howard]

Today's cars are so efficient at burning gas that for your average 20 mile commute roughly half the gas ... in the first few minutes due to the engine not being hot enough yet.

lol

 

[TakeNoPrisoners]

Turbochargers use the exhaust heat to spin the turbo. You add a turbo to a small engine and it produces the power needed to run the car while making the engine more efficient at that power level.

People wrap exhaust manifolds with insulation when the manifolds feed into a turbo.

 

[TakeNoPrisoners]

lol

I agree, 20 miles to heat up an engine? That is insane, my car ends up heating up to operating temp within a half of a mile.

 

[Howard]

I agree, 20 miles to heat up an engine? That is insane, my car ends up heating up to operating temp within a half of a mile.

I was actually referring to the fuel usage...

 

[sm625]

Instead of capturing waste heat, which costs money to do, we need to start with a more efficient and simpler design: http://hittingredline.com/content/power-responsibility-potential-myt-engine

 

[greenhawk]

we're simply harvesting the by-product that's produced: heat. Am I wrong? Is heat not the by-product? I have a difficult time understanding how such is the case if in chemical reactions the by-product is more-less the bane of the process rather than the product that we're aiming for.


I may be crazy to picture giant pistons laid out on their side or at a 45 degree angle on slides driven by a nuclear reaction chamber that pumps dynamos at the maximum rate of 3 RPM (as far as I know our conversion rates from kinetic to electrical is fairly adequate) and have the coolant system pumping the heat exchange from the process to power turbines the same as it does today.

I'm sure once the math is in place and tested properly if you get the right size, weight and design of 4 pistons (maybe in a semi criss-cross pattern) we could find that method of kinetic energy conversion for nuclear fission.

By-product is the unwanted product, so not always heat. In a CPU, the by product is heat, but in a kettle or similar, heat is what is wanted.

So saying "we need to make use of the by product" is not the fastest way to a better system.

As to the chemical reaction and heat being a bane of the process, that is generally reserved for when the by products effect the operation of the primary product or if the by product occur in quantities to make controlling it unviable.

As to nuclear engines, it might be possible, but I sure as hell would not want to be near one. Most current engines expell exaust and other unwanted product out into the enviroment, so making way for fresh material to be used. Doing that with nuclear and containing the output exgust will not happen as that compressed gas driving the piston, needs even more pressure again to compress it back into a smaller volume for storage. Even "treating" it and re-feeding it into the system gets impractical I suspect given the size of the system.

Though IIRC one of the most efficient fuel engines are on the single shaft freighters being currently build/deployed. Over 50% going by the report.

http://www.gizmag.com/go/3263/

As to another person's comment about effency for a powerful engine does not matter as you would have a crap load of energy to work with, the same has been said with most technology over the years and at some point, they try to start improving it. the 25% efficency of a motor or the efficency of a power station all have money being spent to find ways to do it better.

 

[greenhawk]

State of the art, super-temperature gas turbines, can achieve about 45% efficiency. Which can be increased to about 55%, if the exhaust is used to heat water for a steam turbine.

The reason current power stations tend to use water/steam is that the cycle is well understood, and materials for operating at those pressures and temperatures are well characterised.


Similarly, there's no reason why you can't take a nuclear heat source, and use it to heat air , ).

just had to add, with the gas turbine, using the exhaust only helps providing it's flow does not effect the original generator otherwise that restriction in exhaust will happer the main producer of energy.

Water is also used for a few other reasons as well. It is plentiful/cheap and releasing it to the enviroment does not cause issues that have people up in arms very quickly. (they still will, but not to the numbers of most other substances)




The nuclear heat source can work, providing a few issues are addressed. One being the williness of the nuclear fuel to burn in the presence of air at high temperatures.

 

[Colt45]

It's not really practical for much else than heat.

The old radar bases around here, and presumably way up north as well, all ran big CAT diesel generators, they used the waste heat from them to heat the buildings. I guess you could use it to run a second steam generator (w/ more fuel added) but I think it would have to be a pretty big rig before that becomes practical. And in that case, you wouldn't be running a piston-engined generator in the first place.

 

[alkemyst]

There is a lot that uses that wasted power.

I work for a company that designs some spy equipment that can live perpetually on the heat of the engine/exhaust.

 

[TurtleCrusher]

There is a lot that uses that wasted power.

I work for a company that designs some spy equipment that can live perpetually on the heat of the engine/exhaust.

I dont really understand that. Is it based off of flip flop circuits and capicitors?

 

[Mark R]

The nuclear heat source can work, providing a few issues are addressed. One being the williness of the nuclear fuel to burn in the presence of air at high temperatures.

Well, you don't have to use air - but other gases will work.

In the UK, with the exception of 1 reactor, all their nuclear reactors are carbon dioxide cooled.

For reasons of familiarity and turbine plant design, these reactors actually used CO2-water heat exchangers to generate steam and run steam turbines. However, were a similar design to be used today, it would almost certainly use a closed-cycle CO2 gas turbine (which is much simpler, more efficient due to higher temperatures and avoids the corrosion problems that water brings).