Brad Ideas - Stirling Engine based hybrid car - Comments

Please keep your ignorance

Anonymous — Mon, 29 Dec 2008 22:24:16 -0800

Please keep your ignorance to yourself. Your invasion for cheap oil costs this country billions. In no way can it be justified morally, ethically, or financially. Your a moron and your parents were morons. Hug a tree, so your children have an Earth to grow up on, or better yet self sterilization would be best for society.

I agree with most of

Rudy — Sat, 06 Dec 2008 17:00:51 -0800

I agree with most of this

I'd just like to note that these horrible cities are actually the most efficient way for humans to inhabit the world. It is the rural folks (like me) that have the biggest footprint.

There is no technological

Rudy — Sat, 06 Dec 2008 16:56:56 -0800

There is no technological challenge with producing AC from a DC current. DC/AC inverters are widely available, and getting cheaper all the time as magnetics and switching technologies improve and we move to higher switching frequencies. Cheap small inverters are 80% efficient and everywhere. Big ones are 90 or 95% easily.

Once evidence of the improvement of the inverters is the switch to electronically commutated motors (ECM), which run on DC supply, and convert to AC for the motor. With the increased materials costs of copper and steel (for transformers) these high-tech motors are often cheaper than traditional AC induction motors -- the little cooling fan in your computer likely uses this technology (I hope!) ECM cooling fans are often half the price of comperable AC induction fans, and much more efficient.

Diesel vs Hybrid is a non arguent

Russell — Tue, 25 Nov 2008 18:13:36 -0800

See here for two diesel hybrids.
Hybrids fundamentally make sense, and diesel hybrids make even more sense.
So reiterating what others have already stated.

Petrol vs diesel is a valid comparison.
Hybrid vs non hybrid also.
But Hybrid vs diesel doesn't make sense when you can have diesel hybrids.

http://www.treehugger.com/files/2008/02/volkswagen_to_i.php
http://www.treehugger.com/files/2008/02/dieselhybrid_pi.php

Now a reality

James — Mon, 10 Nov 2008 04:04:01 -0800

Apparently this is not all that far fetched. I caught this article posted on Slashdot. It describes a prototype Stirling hybrid electric car.

It should, the jetta is

Anonymous — Sat, 08 Nov 2008 13:49:01 -0800

It should, the jetta is twice its size with 3x as many luxuries and will bomb down the freeway at 100+ mph without breaking a sweat. If the prius didn't beat a gasoline powered jetta in MPG, something would be seriously wrong.

FWIW, even disregarding differences in fuel, the diesel cycle has inherently higher thermal efficiency then otto / gasoline cycle. Combine that with higher energy fuel and of course the MPG is better. Plus, the VW tdi is actually quite a good diesel.

We don't have any of the smaller VW / Audi cars available to us here in america though, the Jetta / Gti is as small as it gets. I agree though, if city driving is not a priority, the jetta / gti will kill the prius in every category except for what comes out of the tailpipe.

On the other hand, one could easily make the same arguement, because the jetta doesn't have (lots) of li-ion or lead acid batteries to deal with when it's junk. Lithium mining is not exactly "green"....

Good luck getting a sterling

Anonymous — Sat, 08 Nov 2008 13:34:18 -0800

Good luck getting a sterling to run happily at 6000+ rpm and still produce any useful torque.

Fuel economy is far worse

Anonymous — Sat, 08 Nov 2008 13:30:33 -0800

Fuel economy is far worse then regular internal combustion engines. Even from a theoretical point of view, the brayton (turbine) cycle cannot come close to even the OTTO cycle, let alone the diesel cycle. The M1 abrams gets approximately 3x worse fuel economy then any comparable tank. It was designed to fight the soviets within 100 miles of bases in western europe- fuel economy and range were not an issue at the time. The main priority at the time was a huge amount of power for very fast speeds in a 70 ton tank, in a small package. These same constraints are why turbine engines are so prevelant in aircraft.

All that heat coming out the exhaust (~1000degF) in large quantities (big mass flow rate) should tell you something about the efficiency right off the bat. You know this by just intuition- even in your post you say "Now harness the heat of their exhaust and you could power a small town!". Also, the tanks are NOT direct drive off the turbine, so the slow throttle response of the turbine itself does not matter in that application. It does matter in an automotive application.

To really get a stirling engine cooking, you need high pressure of a small gas molecule (lots of moles). That is why hydrogen or helium are common choices. It's also why they are a real pain in the ass to manufacture. Then you need a lot of heat transfer through into the hot chamber- no big deal- but on the cold side, you also need a lot of heat transfer to get rid of the waste heat. In the end, you are talking about moving a lot of air and heat back and forth, and some high pressure vessels and dynamic seals that must be SPOT ON to have any sort of useful lifespan. Keep in mind that the throttle responce of a sterling engine is only as fast as you can heat up or cool down and cause heat transfer across the chamber of the hot side- so it would only be practical if used in a sterling / electric configuration.

Someday it might work, put enough pressure in it and get enough temperature differential across it and you might just get the power output you need for a car. Currently however, commercial sterling setups aren't even close to the energy density we need.

Look at those units on the dishes from sterling energy systems. Each dish is 25kw peak. They are concentrating heat on the collector up into the thousands of degrees, and the low temperature resourviour is ambient temperature. Now, consider the size of that engine package- and 25kw = 33 horsepower.

Here is a picture right on their homepage: http://www.stirlingenergy.com/

A lackluster automobile these days is ~120-140 hp, and the latest heavy hitting iron is 550+..... The energy density is not even in the ballpark yet.

The traction thing isn't

Anonymous — Sat, 08 Nov 2008 13:01:42 -0800

The traction thing isn't really too much of an issue- a lighter car doesn't need to generate as much force to accelerate and so therefore the lower traction is acceptable. If you work out the physics, the mass actually cancels out of that equation.

You are correct in that wind resistance is a major factor in fuel economy. One thing to note is that on the highway running at steady speed, a hybrid car may as well be a regular car with a lot of extra baggage. The hybrid components have absolutely no gains whatsoever in fuel economy on the freeway. Their principle advantage is allowing you to recoup some of the energy which would normally go to heating the brake rotors, and use it for propelling the vehicle. The battery reserve / electric motor system also allows you to get acceptable acceleration out of a smaller electric motor by supplementing its power output (from the batteries) in a pinch. Anyways, as I said, none of that helps you at all in steady state, freeway operation- so you see freeway economy numbers similar to non hybrid models.

If you want to further improve, you can switch the gasoline motor in the hybrid to a diesel- the reason this isn't being done commercially is cost. Go look at the cost premium of a volkswagen "tdi" diesel model, then the premium for any automakers hybrid. Add them together, and you get a cost that would be unacceptable for most consumers.

The small weight of a vehicle does not hurt it much in collisions with a fixed object, a bridge / telephone pole / etc. While it has less support, there is less energy to be absorbed, and the acceleration tends to be about the same. Go check out the crash test video for the smart car...

Now, when it runs into a fully loaded ford excursion powerstroke, towing a trailer- that is when things will be bad. Due to the laws of momentum the huge car will have very little acceleration and the light compact car many times what it would have even if it hit something that was fixed (bridge, pole, etc). You can chase your tail trying to add more crumple zones etc, without increasing the weight- some gains are possible that way but it really isn't that practical. In reality, it just isn't possible to make it a fair fight, and there is little you can do about the large accelerations which will be present, other then to try to minimize the peak values (crumple zones).

Crumple zones can't really solve this problem as a zone that would work well against a pole wouldn't be optimum against a vehicle 3-10x its weight. Seat belts IMO are at the limit of what people will actually wear- odviously past it to some morons... Same goes with interior padding- that's basically what an airbag does and we've sort reached the limit for that especially in higher end cars, with front bags, side impact curtains.

"Turbines, well they've been

Anonymous — Sat, 08 Nov 2008 12:32:59 -0800

"Turbines, well they've been about for over 60 years now. The first 'production' car was a Rover in the 1950's. The fact they're not in common use should tell you something!"

Ya, it tells you that Brayton cycle engines in a small / lightweight configuration have even LOWER thermal efficiency then otto cycle gasoline engines. Combine that with sluggish throttle response unsuitable for typical automotive use and you will realize that big oil has nothing to do with why turbines are not utilized in automobiles.

If anything, big oil would love it. I'm sure they smile every time they see an M1 Abhrams tank roll by. Turbine powered and the worst fuel economy of any tank in the world.

power generation

R. Kraft — Tue, 28 Oct 2008 08:47:48 -0700

Most of the contributions to this subject are limited to rather feeble minded reasoning. I, for my part, do not favor nuclear - nor combustible (coal,oil) power generation; there are many other means that are far too less exploited.
For the past six years, I've heated my home with a heat pump and produce electric power(15 kWp)with a photovoltaic system. More than half of the produced power is distributed to the grid; the minor portion I use for myself. There certainly is room for improvement of efficiency of currently available systems but I can't afford to wait for the non-plus-ultra until my life expectancy has expired; for that matter, nor can anyone else. Don't wait until tomorrow, ACT NOW. Pollution isn't waiting, it's steadily progressing from day to day.

Why not Lightning Economy? First proposed by Avito Hong in 2008.

Olivia — Sat, 04 Oct 2008 05:57:53 -0700

This is a new interesting technology, please keep reading.

There are currently three potent ways to store the ultra large amount of lightning energy, just a matter of initiatives and funds to start it about. A lightning storm can power the whole USA for 20 minutes. In every second, there are currently 2000 bolts of lightning flashing in the skies.

1. Use high heat capacity metals to store current-induced heat. Current of the lightning will pass through metals like tungsten(don't think tungsten is rare and expensive, it's cheap in fact) or silicon to produce large amount of heat. The heat is gradually tapped.

2. Store through electrolysis, yielding hydrogen. Electrolysis is definitely cheaper - water is free, metals are not free.

3. Supercapacitors, there is a variety of supercapacitor (must be instantaneous rechargeable) like superconductor magnetic energy storage (SMES), carbon nanotube ultracapacitor, highly porous ceramic supercapacitor. Some of my examples are yet under research and development. These supercapacitors are connected in series and a Bang could replete them with full of current.

Lightning can be induced in three ways:

1. Place lightning bolts in highlands.

2. Fly mini rockets with copper wire attached.

3. Flashes very high power lasers into the clouds, to ionise the air. Ionisation causes the atom to release electrons, and ultimately reduces resistance. Thus, pulsing beams of laser is like pulling the clouds with a copper wire.

You probably heard of hydrogen economy and nitrogen economy, but mine is Lightning Economy. Since lightning produces an ultra large amount of energy, it can replace fossil fuel instead if researches are done exhaustibly. Run trucks and cars with battery, run Industries with ultra low electric bills, produce very cheap products, increase exports, free energy for mining resources, no more home electric bills..... Readers, please further think about this and keep this idea in your memory.

How about a hybrid that

Anonymous — Wed, 24 Sep 2008 20:59:33 -0700

How about a hybrid that incorporates a gas or diesel engine combined with an electric engine and a stirling engine? All three could be used to power the wheels. The gas and electric engines could be used the same way an ordinary hybrid normally uses both of them, but the stirling engine runs off of the waste heat from the internal combustion engine, the electric engine, the batteries, etc., or anything in the car that produces heat. This way, you are recapturing the energy in an engine that 70% of is normally lost through heat. The stirling engine can be used for either charging the atteries or for directly powering the wheels.

Our Dieing Planet

wade polk — Tue, 12 Aug 2008 07:00:53 -0700

It is great to here people discussing this. I am an engineer working in the power industry and thought I'd make some comments.

1) Nuclear power is cheaper over the life cycle of the plant. If the civilian sector had the same regultations as the military sector, it would even be cheaper. There is a false debate in the media concerning the nuclear waste. I ask, why does this debate not cover military nuclear waste which is the majority of nuclear waste produced and is not regulated. Besides, we pull the uranium from the ground, and put it back in when we are done with it; whats the big deal? It's better than pumping our waste to the atmosphere where it can be inhailed by our children and taken directly into the blood stream (no filtration or breakdown as in the stomach). I'm going from memory, but coal emissions are typically as follows:
70% CO2
10% SO2
10% NOX
10% volital organic compounds (cancer causing and other unknown affects)
.004% mercury (this is larger than you think considering the affects of mercury on life. to give an example, if a pregnat women were to eat fish every day of her pregnacy, statistically speaking, both the women and the child would experience mental difficiencies if not death. This is a big problem, as the fish eat fish and mercury cannot be excreted by life, so the process is cumulative. Fish is a staple food of humans as well as anaimals. An interesting fact is that when the tests were completed and determined that mercury levels have been tripled in every fish in the sea, they raised the legal limit for mercury and kept in quite.)
% Others

2) Wind power is getting better and better and will continue in this manner. Currently there are 5 MW wind turbines and 50MW wind turbines on the horizon. To give you an idea, coal power plants usually produce between 200-1000MW per turbine. Nuclear is between 900-2000 MW per turbine. The nuclear fuel cost is negligable since tens of thousands of tons of coal are not needed (fuel only needed to be changed every 2 years)

3) Wave power is really comming along and, in my opinion, is just another extention of wind power which uses the entire planet as a wind tunnel.

4) Geo thermal is great.

We have more inportant concerns at this point than money. cancer rates have risen from (historically) 25% to 35% of the population dieing of cancer in just 50 years. Imagin what will happen to the human race in 100 years if we "maintain the course". Additional affects of coal exhaut that can be seen in every city around the world include sperm count reduction, increase in asma, smog, dirty residues, posioned oceans, global warming, learning difficiencies, global water acidity and temperature changes (currently responsible for the disappearance of corral refs, which are expected to be completely extinct within 100 years), cancer, ozone reduction, increase in automospheric particulate count (possibly causing global dimming), possible sea level rise and melted ice caps (the full affects of this are unkown, but probably extensive), and the list goes on.

Hydrogen is a fix to our problems. yes, it's not extremely efficient, but it is better than gasoline in terms of efficiencies. hydrogen from coal power plants is just an absolutely rediculus concept do to similar reason. Hydrogen will always be the best fuel source for our vehicles because our planet is covered by 2/3rds water and all our emissions can be condensed or vented to atmosphere as water only. Zero harm will come from our emissions and no loss of performance of our vehicles is required (though the range is less, typically half the range of gas engines, though still 200 or more miles).

At this point, money (or should I say profit) is not an issue. I suspect all people of the planet will realize this in 10 to 50 years. The problem is, it may already be to late, as the evidence is mounting that the process we have started is a positive feedback system that can't be stopped. We have already doubled the amount of CO2 present in our atmosphere in just 50 years and our emissions have been rising exponentially.

Hydrogen as power storage

Anonymous — Fri, 01 Aug 2008 23:19:21 -0700

There is another issue here too, electrolysis and/or fuel cells produces DC current. Most components in the US use AC so you will have to rectify or (worse) burn the hydrogen to get your AC. It just doesn't make sense in most cases. Now you develop a case where you can use DC on site you may have a point. I have thought about this in the past and the most reasonable idea I can think of is Sever Farms (huge demand for DC in localized area).

Nuclear on the other hand is here now, works, and can provide most of the power needs for entire planet safely. Disagree with that comment, look no further then France.

The biggest hurdle to making nuclear work is dealing with the waste. We do have several options available to use now though; such as deep sea burial, glass pucks, and my favorite, launching it at the sun (fusion wins over fission) :-). Truth be told we Americans are just to damn scared of it.

Stirling Engine based hybrid car

brad — Wed, 02 Jun 2004 15:58:35 -0700

I'm not the only one to have thought of this, but as yet no real work has been done. How about a hybrid car powered with a Stirling Engine? (Not spelled Sterling, btw.)

The Stirling is more efficient than the internal combustion or diesel engine, and it's also a lot quieter. Sounds great, but it's not good for cars because it can't rev up quickly and it takes about 5 minutes to get the engine hot enough to run well. We want our cars to start the minute we put the key in.

A hybrid design (with enough batteries for 10-20 miles) solves this. You can get all the acceleration you need from the electric motors, and you can start driving right away, while heating up the Stirling "boiler". Then it kicks in to provide the power to run the car for the long haul. If you know the trip is short, no need to fire up the Stirling until the battery gets low.

The Stirling can burn anything. Gasoline, kerosene, diesel, vegetable oil, hydrogen, even wood! Yes, you could, in theory, be stuck by the side of the road out of gas, then go out with an axe to chop trees and refuel your car.

Well, almost. You want high-temperature burning for the best efficiency, and this would pollute and probably dirty your nice clean boiler. Right now the engines are expensive to machine but I suspect that could change.