Utah Teens Invent Better Air Conditioner

Carl Youngblood writes "Two recent Utah high school graduates won the first-ever Ricoh Sustainable Development Award for inventing a better car air conditioner based on the Peltier effect. The peltier chips used in the device are more energy-efficient, last between 20 and 30 years, are solid-state, and don't harm the environment with ozone-depleting freon like today's car air conditioners."

Comments

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[GoogolPlexPlex]

I wish they had built a better server.

Re:/.ed

[pcmanjon]

Ahh, I "read the fucking article" and now I understand. The main article makes you think a couple of chips save the day, and makes A/C's last longer. They do, in a way, but the article on ./ here should have quoted the real article, instead of trying to paraphrase.

"Today, the young inventors say, U.S. drivers use about 7.9 billion gallons of fuel each year to run their air-conditioners, which draw power from the engine. By adopting their contraption - which taps into the electrical system, using fans to blow hot air through five Peltier chips and then releasing cold air - they say the country stands to save 3.9 billion gallons of fuel annually, or about $10 billion based on current gas prices."

Re:/.ed

[HeroreV]

It doesn't say 20 to 30 years longer, it just says that the peltier chips "last between 20 and 30 years". I have no idea why you just randomly inserted a word, but that's exactly what you've done.

Re:/.ed

[Jumperalex]

Wel I can't sak you if you even RTFM'ed since I haven't either (damn /.) but I can ask if you even RTFS (read the f%ck1ng submission)?

They are mention the use of peltiers. Those are SOLID STATE heat pumps (for simplicity sake). that means no regrigerant (since Freon is a brand name) and no moving parts other than the fans on the hot and cold sides and the extra large alternator to power it.

Re:/.ed

[modecx]

Yeah, of course this contraption ain't gonna be anywhere close to the efficiency of a decent/good refrigeration system.. I'm no AC guru, but I understand that refrigeration systems can be very very efficient. 80% on the low end and 90+% on the high end. That's pretty astonishing in the mechanical world, where typical engines are less than half that efficient.

"Invent" is a pretty strong word when you can go and find those mini in-car /desktop "silent refrigerators" using peltier chips at Cost-Co for $100.. They're not at all efficient, but if the need scratches... Itch it.

If one determines that it takes 5kw to cool a space then that's what it takes. At that point, it dosen't matter except for efficiency and other factors (i.e. environmental concerns) what you use to move the heat, but that's the power you'll need to provide... Unless you're using magic or mutant powers or something.

In this car, we obey the laws of thermodynamics!

Re:/.ed

[vijayiyer]

And the electrical system gets its energy from the alternator, which gets its energy from the engine. Conservation of energy is alive and well...

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[Charcharodon]

Don't see how it is going to "save" fuel since taping into the electrical system puts a load all the same on the engine. Instead of the AC/pump getting the load the Alternator does.

Of course it is possible that the Peltier chips are more efficient, but considering the ones found on most electric coolers are around 60watts each I doubt it, considering you'd need 10-20 of them to keep up with the heat (the summers in CA are tough).

The real advantage would be that they are simple and wouldn't need to be connected directly to the engine. So if 1-5 broke you might not even notice.

Re:/.ed

[AaronLawrence]

Except for one tiny details: they are not. They are an order of magnitude LESS efficient at moving heat.

Let's not let facts get in the way of a good story though.

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[Rei]

Yeah, this article sounds like "really, really bad misunderstanding of science".

The reason why the Peltier effect isn't used everywhere a heat pump is needed - and it's a really neat effect, mind you, as it has no moving parts, little to get corroded, is small and lightweight, etc - is that it's inefficient. We're talking god-awful inefficient until recently (~5%), and even now we're trying to stretch it to ~20% in the lab (no easy task).

As another poster mentioned, conventional refrigeration systems are quite efficient - at least, by themselves. Now, for a home refrigerator, it doesn't work out so nicely, because your power is being generated at 50% efficiency, transformed multiple times at a loss, suffers transmission losses on the way to your house, etc (that's why propane and even solar refrigeration systems are more efficient). But for a system like in a car, where the motor is directly running the compressor, it's going to be very efficient.

The Peltier chips - inefficient on their own - suffer from the inverse problem that the refrigerator suffers from! They need DC electrical power, but what the car engine produces is mechanical power! The car's alternator produces AC at a loss, which is rectified to DC, which then goes to the lossy Peltier chips. Assuming "ebay chips" are, say, 5% efficiency, we're looking at an overall system efficiency of 1-2%. Yeah, great way to save gas.

Re:/.ed

[dbIII]

Of course it is possible that the Peltier chips are more efficient

Obviously the laws of physics are different in Utah - elsewhere the peltier effect was understood and applied decades ago. Heat pumps do it the easy way with a lot less energy than the peltier effect, which has to do it the hard way. It doesn't take a lot of energy to move a gas and expand it, which is why you get an order of magnitude more heat moved that way than with the peltier effect. It's interesting stuff (look up thermocouples too - they work on the same principle) but not what these people think it is.

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[modecx]

The other sad facet of this is that if they intend to run this off the typical 12v system in a car it's going to need 83 amps of 12v per 3400BTU/hour (1000 watts) they intend to move even at 100% efficiency, ignoring losses in the cable.

Gonna need some real Monster Cable(tm) to handle much of that! You know.. You should be worried when they start looking for cable in the kcmil range.

Re:/.ed

[Hadlock]

I don't know if you've ever worked on a car, but if you know what you're doing, you can change an alternator in about 20 minutes, or get it replaced at the dealership for $150. It costs that much to have someone look at your A/C system, let alone work on it. The A/C system truly has no user serviceable parts.

Re:/.ed

[rogerzilla]

Except that car alternators are surprisingly efficient - up to 90%. In fact, if it wasn't for the power supply difficulties (a typical 4kW unit would draw 333A at 12V), electrically-powered car a/c would have a huge advantage - it doesn't need expensive servicing every 2 years because there are no shaft seals open to the outside, hence no refrigerant leakage.

Domestic fridges are the most reliable applicances in the home because they are built as a completely sealed unit.

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[Lumpy]

Those numbers are skewed. Today's cars use more gas at highway speeds if only one window is down compared to the air conditioning. Hell the econobox I bought to beat gas prices loses only 1mpg when the AC is on (based on using a tankfull of gas. Comparing a month of commuting in cooler weather with only fan and vents open compared to the tankfull used when the AC was on full blast non stop.)

Older cars had horribly inefficent AC systems, and larger vehicles that have the equilivant of a house sized AC system also have horribly inefficent AC systems.

One of the most efficent AC setups in current production vehicles is in the Honda Insight and Toyota Prius. using less than 72 watts of electricity to run the electric compressor and a synthetic compressor oil + newer coolant technology.

you can not get near the efficency of a phase change cooling system with peltiers.

Re:/.ed

[crath]

But Google's cache does have a copy.

Re:/.ed

[budgenator]

1,1,2,2-tetrafluoroethane R134 is still ozone depleting but not as bad as the old R12 stuff is. What I can't figure out is given the
1. equilibrium of the Halides in the upper atmosphere in destroying ozone, about 1:35 a BadThing(tm),
2. the tendency of the halides to concentrate over the poles, a GoodThing(tm),
3. the large number of balloons send up to study the "problem"
wouldn't it make more sense to just say, we don't know if it will help or not, but if your package doesn't have a chemical pack to sequester atmospheric halides in the upper atmosphere, we're not going to give you any grant money for your study period.

Re:/.ed

[BillyZ]

Those numbers are skewed. Today's cars use more gas at highway speeds if only one window is down compared to the air conditioning.

Completely false. This statement is a common urban legend, and nothing more.

Using your AC taps mechanical power from the engine. This requires you to use more gas to maintain the same speed. Opening your windows adds some wind resistance, but doesn't add the same amount of loss as engaging the AC compressor. (you should watch mythbusters sometime, its a great show!)

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[Digital Vomit]

Today's cars use more gas at highway speeds if only one window is down compared to the air conditioning.

Didn't the Mythbusters prove this one false (albeit in a somewaht flawed test)? The car with the open window ran significantly longer on the same amount of fuel.

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[TheScorpion420]

However unlikely it sounds this would save gas. It takes a lot of engine power to run the compressor for the A/C. Don't you notice how your engine bogs down when you turn the A/C on? You have to apply more throttle when the A/C is on to produce the same amount of acceleration or hold a speed than when it isn't on, thus you burn more gas. However the alternator on a car takes significantly less of the engines power, most people when driving don't even notice when the alternator kicks on, so the system can be massively inefficient but still save on fuel simply because it is taking electrical power instead of mechanical power directly from the engine.

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[nuxx]

Did you note that the also ran the vehicles at 45MPH?

Change the speed to typical highway speeds (70MPH here in Michigan) and I bet the story would change quite a bit. I know that my car (a standard smallish sedan) drags quite a bit when you open the windows at highway speeds. Windows up and AC on, the throttle doesn't have to be depressed nearly as far in order to maintain higher speeds.

I'd agree that at 45MPH and below the AC is less efficient, but start getting up to faster speeds where the turbulance caused by open windows creates a *lot* of drag and I think the difference will be pretty obvious.

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[rogerzilla]

But drawing more power from an alternator increases the back e.m.f. and the engine has to work harder - you don't get nowt for owt and if you were drawing power for a large a/c unit from an alternator you would feel it kick in, I promise.

Thinking about it more, the reason car a/c is belt-driven is probably because no-one makes an alternator that can handle the current to an electrically-driven compressor. Ideally you'd have TWO alternators, one running at 12V (or 14.4V, which is typical) and the other running at 400V to drive the a/c without using huge fat cables.

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[ebh]

That's not too bad of a mechanical problem, but the real danger of higher voltages in the engine compartment is sparks.

Because of the huge demand for current in modern cars (when's the last time you saw a window crank?), the automakers are trying to move to a 42V electrical system, but they're having a hard time bringing down the costs of all those gas-tight connectors, not to mention devising safe procedures for jump-starts etc.

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[jazzkat]

Completely false. This statement is a common urban legend, and nothing more.

Completely true. While the A/C taps power from the engine, rolling down windows taps more power from the engine to overcome drag.

I have a 2001 Chrysler Sebring sedan with the 2.7 V6 and one of those nifty trip computers. I use synthetic oil. At 75mph, I get around 31MPG. With the A/C on, that drops to 29 MPG. With the A/C off and one window down, that drops to 26 MPG. (This is with the cruise control on - so no lead foot to take into account.)

Care to back up your assertion with some facts?

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[ginbot462]

Most manufacturers wouldn't won't to present milage in a bad light. So, gas milage is probably always calculated with the least drag (windows up) and a/c off. So while I doubt they have to report milage with the top down, that would be interesting to know.

Second, convertibles on average will get worse gas milage. They are not as smooth and are heavier (to add support for since the frame doesn't wrap fully around).

but, no one buys a convertiable to save on gas. And if you bought a Geo convertiable, 'the hell's wrong with you?

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[silicon not in the v]

Using your AC taps mechanical power from the engine. This requires you to use more gas to maintain the same speed. Opening your windows adds some wind resistance, but doesn't add the same amount of loss as engaging the AC compressor. (you should watch mythbusters sometime, its a great show!)

I watched that episode of Mythbusters about the A/C vs. open windows debate, and their conclusion was that it was pretty close to even. Their test results could barely find a difference, but their testing methods were so horrible(as in not real life) that I found any conclusion they would come to worthless. The biggest aspect that screwed up their results was that the identical vehicles they were using were both huge SUVs with V-8 engines. Of course an A/C compressor isn't going to be much of a load(proportionally) on that powerful of an engine.

I have always had small 4-cylinder cars, and in them, when you turn on the A/C, it feels like the car just hit a construction barrel. It's pulling a much larger percentage of power from the engine than on those big SUVs. That large percentage of power would translate significantly to lost fuel efficiency.

The other aspect about the Mythbusters test that was messed up was that they were running them around a closed-in, banked racetrack. The handling limitations of the SUVs on that track forced them to keep their speed down to about 45mph. Those two factors--the low speed and the sheltered from the wind environment pretty much take the wind resistance factor out of the equation.

So, myth: The Mythbusters show proved something about the A/C vs. windows debate? BUSTED!

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[sirket]

That was one of the less intelligent bits of testing they have done on that show and some of their test rigs have been doozies. Let's list some of the problems:

1- When they tested the car at 55MPH using the computer it showed that using the AC was more efficient. Jamie wrote this off as "Yeah but the computer was measuring airflow and not fuel consumption." Modern engines use O2 sensors and closed feedback to maintain stoichiometry. As a result if you use less air the engine will inject less fuel to maintain stoichiometry or the appropriate air-fuel balance.

2- When they did the objective testing they drove at 45MPH and not the 70-80 commonly done on American highways (Don't claim people don't drive this fast- get on any highway in New Jersey, New York, Mass, or Maryland where I drive). Drag increases exponentially so this can make a _huge_ difference.

3- Instead of draining the fuel tank they siphoned it out instead. They could have missed the fuel in the sump on one car and gotten it on the other. As the difference in economy was only about 15 miles (less than a gallon of gas) it could have made the difference on it's own.

4- They used two different vehicles for the test- as the difference was so small then it could simply have been a result of engine differences, tire pressure differences, air cleaner performance differences, transmission slippage, etc.

-sirket

Re:/.ed

[Charcharodon]

I cut my original response in half. I was starting to bring up that fact as well. Having Peltier units installed would and have one go bad would reduce repairing your A/C unit to something akine to changing a light bulb. That and the fact that you would have quite a few of them installed would prevent a total loss of your cooling system should one fail.

After looking online at a few sites I did find some interesting peltier coolers that might do a good job, but you are still talking about 500-1500 watts to do the job.

Well duh not thinking too well this morning, just remembered that the trend of auto is going towards hybride which happen to have 5000-15000watt generators built in. Maybe they're going to be practical after all.

It would be interesting to have them installed in a vehicle with a roof covered in solar cells. They could left on to keep things from heating too much while you were gone. Due to there nature they could also be intergrated into places such as the floor or the roof where they wouldn't take up much in the way of space.

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[Tacky the Penguin]

I'd agree that at 45MPH and below the AC is less efficient, but start getting up to faster speeds where the turbulance caused by open windows creates a *lot* of drag and I think the difference will be pretty obvious.

Without turbulence, aerodynamic drag increases linearly with velocity. With turbulence, it increases with the square of the velocity.

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[dbIII]

I don't know where you get the idea that it doesn't take a lot of energy to compress the gas down in the first place (which you have to do to get it to release the heat)

I suggest you get hold of any first year university thermodynamics textbook - refridgeration is explained well in all of them.

One old and simple example is the kerosine refridgerator. In that case the compressor is a reservior of water, ammonia is the working fluid, and kerosine is used to provide flame to get some heat input to keep it all moving before the expansion nozzle.

compressing the air you want cooled, running it through cooling fins, then expanding the air and releasing it.

It's a lot easier to compress the working fluid/gas, run it through a cooling system (for example the exposed copper piping with a big surface area on the back of old refridgerators), then expand it. Gasses that we can do this to easily are the ones that are used as the working fluid - with air it's a lot of hard work to get the CO2 out so you don't get solids and then compress the nitrogen down to a liquid. It's far easier to cool something else and blow the air past it than to compress and expand nitrogen.

No more freon in cars

[ToadMan8]

Cars sold in the states haven't used Freon since the late 90's. That's why A/C sucks in cars now.

Re:No more freon in cars

[AKAImBatman]

I *still* think that Cryocoolers are the way to go. You can't tell me that a Stirling or Pulse Tube cryocooler would cost that much more to mass produce than a regular AC unit. Not to mention that the engine load would drop to an unnoticable amount in comparison to today's AC units. Even the EPA's own documents mention Stirling coolers as an acceptable solution! :-)

Re:No more freon in cars

[jimi the hippie]

All cars with A/C still use freon. They don't use R-12!! (which is the stuff that supposidely depletes the ozone, and has been illegal since about model year 1995, NOT the late '90s)

Freon != R-12

Re:No more freon in cars

[pongo000]

This should actually have been modded as "misinformed" (don't we wish...)

R134a A/C systems have evolved over the years. Granted, the early systems left a lot to be desired, but the output of the recent systems rival that of old R12 systems. R134a systems are very pressure-dependent, far more than R12, and must be precisely charged for maximum effectiveness.

It's hot here in Texas, at or above 100F in the summer, and both of my Chevy trucks (an '02 and an '03) blow frigid air.

Re:No more freon in cars

[minus_273]

well that and the insane amounts they have to spend on workers salaries and benefits when compared to the rest of the world. There is no way they can compete. It's funny when you realize that becasue of the unions and their short sightedness, many of those jobs will disappear in the next decade or so.

Re:No more freon in cars

[JanneM]

well that and the insane amounts they have to spend on workers salaries and benefits when compared to the rest of the world.

Other companies around the world do pay for pensions and health care as well. Not by setting up their own insurance funds, but by paying higher salaries (to compensate for the higher income taxes on those salaries) and by paying sometimes quite high employer fees. The difference is really that in state-run system everybody shares the cost, while for the US carmakers they are stuck with the bill for a lot of workers all by themselves.

Re:No more freon in cars

[CurlyG]

You're delusional. You really thing the average German worker in the automotive industry gets lower salaries and fewer benefits than his equivalent in the US?

Try again.

Re:No more freon in cars

[drsmithy]

well that and the insane amounts they have to spend on workers salaries and benefits when compared to the rest of the world.

You mean compared to countries like Germany and France ? (Well known everywhere as bastions of conservative capitalism and mercifully free of the unionised workplace).

Re:No more freon in cars

[majikenny]

nah, people here are just geeks in general. Thus mechanical engineers arent entirely out of the allowed crowd, just not the main group. now if he was in marketing or something, that'd be a little wierd. but engineers are just as geeky/nerdy as you crazy computer foklks.

Re:No more freon in cars

[AKAImBatman]

Errr... no. There are no cryo liquids in these coolers. They're used to make cryo liquids, although in much bigger form than you'd use in a car. A Stirling Engine is a reasonably simple device. You have two pistons, a regenerator, a hot surface, and a cold surface. Heat the hot surface, and you get energy as the heat is pumped to the cold side. Apply energy to drive the engine, and the cold side will pump all its heat to the hot side, making it that much colder. Damn efficient devices, they are.

I briefly discussed this topic recently when we were talking about keeping computers cool. The heat problem is becoming so critical that Intel is actually designing a Pulse Tube cooler for their microprocessors!

Re:No more freon in cars

[Anonymous Luddite]

>> but a typical healthplan for my professional friends costs $10,000-12,000

According to my company, the non-cash benefits I receive cost them (and our customers ultimately) more than half my cash salary in addition (I do have an excellent benefit package though)

>> And Japan has alot of socialized services, such as National Health Care. As a result, the Japanese corporations are able to remain much, much more competitive

having company-run unions help the japanese corps *just* a little bit there too.

Re:No more freon in cars

[dreadknought]

The EPA also approves about twelve refrigerants for use in automobiles. You know how many the automotive industry approves? two. R-12 and R-134a. You will never find a shop anywhere in the world that will charge your A/C with anything but R-12 or R-134a. Just because the EPA approves something for automotive use doesn't mean the industry will. Afterall, the EPA most likely aren't experts in the field of automotive airconditioning.

Re:No more freon in cars

[mrchaotica]

They proved that false on Mythbusters a while back. Of course, wind resistance increases with the square of the speed, so the faster you go the closer you come to breaking even. Seeing as how they tested at 55 MPH (I think), if you're doing 70 or 80 the AC might be more efficient.

You're right that the AC keeps you cooler, though...

Re:No more freon in cars

[forty7]

Since you're picking nits anyway... :o)

98.6 is a fairly bogus number with respect to significant digits. It is just 40C converted to Fahrenheit, but even that number is plus or minus a degree or two for normal population distribution.

It's just 37C converted to Fahrenheit. 40C is 104F.

Re:No more freon in cars

[DigiShaman]

No, A/C sucks because the major car manufacturers are too lame to figure out how to build good A/C without Freon. It's possible, they just won't do it.

American auto manufacturers especially. They fail to innovate, and are going down the tubes. Nobody to blame but themselves, really.

As long as it's American bashing going on, this WILL get moderated up.

Fact is, EnronHaliburtons post is a troll! And he knows jack shit about the auto industry or how A/C systems work in general. Had he done his homework, you would realize that the FACT is R134 is LESS efficient then R12. That's correct EnronHaliburton2004... you troll. Do your god damn homework. And no, I won't do it for you. Google it.

While were at it, AC systems have always blown less cool regardless of the auto manufacture. This isn't an American sucks issue. This is an R134 sucks "issue". I bet my Honda on that!

Re:No more freon in cars

[mboverload]

They did a special episode behind the scenes that shows they really DO do experiments over and over again. Lots of times. It would just be boring to put that in the episode.

Re:No more freon in cars

[donscarletti]

I never thought I would ever see a single comment that both mentions a Texan's two Chevy trucks and contains useful technical information about refrigirative gasses.

I have been proven wrong by slashdot once again.

Re:No more freon in cars

[curious.corn]

Speaking of Germany: the country has done extremely well for decades. It has one of the most advanced mechanical engineering industries of the world and it's economy has always been the driving point of the whole contintent. Things started to wobble whith the reunification but let's be real, it's like suddenly running with a dead horse on your back. Yet they're still doing fairly well and shurely much better than other countries like Italy. You see, unions or high salaries are not a problem (what's wrong with high school teachers affording Mercedes Benz cars?) as long as they contribute to the sustainment of a market loop. The real point isn't about crushing labour, it's about taking responsibility and creating value add rather than going for a hit and run.

Italy for example is the worst example of antieconomic administration ever: entrenced 'corporative' unions that blindly protect privileges granted by unscrupulous policians for clientele sustainment; credit martket held hostage by individuals (yes, individuals... not even interest groups or boards) playing power games amongst themselves rather than just selling capital to investors.

Unions just represent part of the stakeholders, they're not bad per se. Of course in China, India or S America one can completely ignore them and eat the workers' cake but that doesn't mean being profitable, it's theft.

Eventually you have to admit that there's nothing bad in paying for labour as it produces the value add you sell and probably consumes it too! The point is going for the value add, there's nothing worse than stagnation with high salaries. Like sharks, economies have little if no buoyancy, if they stop swimming they sink.

Re:No more freon in cars

[Ignignokt]

Post taxes, probably. Post the 10%+ of them that are unemployed, certainly. Maybe their US counterparts in the automotive field will catch up to them in the latter category in the next decade, but they're not there yet.

Re:No more freon in cars

[Anonymous Coward]

IAAME (mechanical engineer)and work in the cryo field, I'll contribute my $.02. Actually, Stirling cryocoolers do cost more to mass produce than regular A/C units. The tight tolerances and high grade materials required drive up the cost. Cryogenic applications require oil-free compressors and expanders because the oil would work its way to the cold head and freeze, destroying the cooler. Oil-free compressors don't have the reliability for an automotive application.

IAASAEM (Society of Automotive Engineers Member), I don't work in the automotive field, but I'm a geek interested in cars. From their magazine: The automotive industry calculates cost to the penny, and if there was some technology that was cheaper, improved mileage, or help cut emmisions (by not working the engine as hard), they would probably use it. There are numerous technologies in the works, but changing the A/C involves changing a massive infrastructure from manufacturing to maintanence.

Re:No more freon in cars

[instarx]

Your statistics are misleading and mis-applied. The German unemployment rate for June 2005 was a whopping 20.5% in the former East German sections of Germany, while the country's overall unemployment rate was 12.5%. Therefore the western, industrialized, parts of Germany have a rate roughly comparable to the US.

The overall 12.5% jobless rate is clearly not a result of unionization or social programs as you imply, but from re-unification problems. I dare say that if Mexico were added to the US overnight our unemployment rate would skyrocket too.

freon?

[schematix]

The peltier chips used in the device are more energy-efficient, last between 20 and 30 years, are solid-state, and don't harm the environment with ozone-depleting freon like today's car air conditioners."

Ahem. "Today's" cars use R134a refrigerant, not ozone-depleting freon. This has been the standard for a little less than ten years now.

Re:freon?

[Technician]

In the new Prius, the AC is no longer belt driven. This eliminates the shaft seal, a common wear and slow leak source. The new AC is electric using a sealed compressor much like a home AC unit.

The peltier chips used in the device are more energy-efficient, last between 20 and 30 years,

I have a solid state ice chest. I don't believe the expected life rating when applied to a solution where condensation is present. It does not apply when they are used in high humidity. Corrosion from condensation kills these in a very short time. The module in my fridge died long ago from condensation caused corrosion. I would not want these in any application that runs below the dew point. Since my AC in my car is designed to run below the dew point to defog windows, there is no way I want a cooling solution that dies when it gets wet. Speaking of more energy-effecient; More effecient than what? Older modules, compressor driven? I have not seen any peltier chips ready to replace the compressor driven freezers and window AC compressors. They simply don't remove enough heat.

An advantage a working fluid AC has over a solid state solution is the hot side can be far removed from the cold side. The radiator for most car AC units is in front of the engine in cool air. A solid state AC would have the hot side behind the engine next to the passanger compartment. Just where were they planning on putting their waste heat? A typical car AC unit is over 20,000 BTU's. How many BTU is their system?

Frigidaire got to them...

[aapold]

Frigidaire got to them. Don't mess with the cooling conglomerates...

Re:Frigidaire got to them...

[MrNonchalant]

...they'll put you on ice.

Ka-ching!

sweet!

[sams2100]

I can now overclock while I drive!

Google Cache

[j00bar]

If you're having trouble seeing the article, try this: Google Cache

Re:Google Cache

[Alsee]

Salt Lake Tribune printer version of article working link.

-

Freon isn't used in new cars!

[DarkHelmet433]

Freon (R-12) hasn't been used in new cars for something like a decade now. R-12 is an ozone depleter. It hasn't been manufactured in the US since the mid 90's or so

Newer car air conditioners use refrigerant R-134a. This is *not* an ozone destroyer, but it is still a greenhouse gas.

Peltier coolers use electricity, which is generated by the horribly inefficient internal combustion engine which produces greenhouse gasses and other toxins by the boatload.

It's all bad. :-(

Re:Freon isn't used in new cars!

[Muerte23]

Peltier coolers use electricity, which is generated by the horribly inefficient internal combustion engine which produces greenhouse gasses and other toxins by the boatload.

Not to nitpick, but the compression cycle of regular car AC is also powered by the motor...

Plus, if your alternator can handle it, the peltier is probably much lighter, and certainly much smaller, further improving your engine efficiency.

m
this is not a sig

Re:Freon isn't used in new cars!

[DarkHelmet433]

To refer to posts above, the peltier coolers have a severe disadvantage.

#13120684: Normal peltiers have an efficiencies of less than 30% Modern air conditioners have an efficiencies approaching 400%.

#13120746: Modern aircon works by using matter phase change and using pump to move the fluids. It transfers more heat than the energy consumed in moving the fluids.

So while I don't have one of these, I'm really really sceptical that the CO2 and other greenhouse emissions per unit of cooling by a peltier can get anywhere near a modern air conditioner.

Re:Freon isn't used in new cars!

[ErichTheWebGuy]

OK, allow me to put some things into perspective. In addition to being a MCSE, A+, etc. certified geek, I also hold EPA certification to handle refrigerants and to service and install refrigeration systems in commercial, residential, and automotive applications.

The parent poster is absolutely correct, R134a is a greenhouse gas. However, that statement should be qualified: it is only a greenhouse gas when it is released into the atmosphere. Modern technicians use recovery equipment to remove refrigerants from cooling systems (everything from your freezer to your central A/C). The refrigerant is either recycled, or disposed of properly.

As long as we are all conscious about our environment (and we all should be, lest anyone turn us in to the EPA, causing us to have to fill out the reams of paperwork!) there is no problem. Oh, and there is always that pesky thing about preserving the planet for generations to come :)

I, for one, am quite sick of people blowing things out of proportion when there is no real problem. Having said that, kudos to the two teens for their inventive spirit. Maybe with some refining, the invention will prove more efficient and ultimately prove commercially useful!

Re:Freon isn't used in new cars!

[ErichTheWebGuy]

Good point, and also absolutely correct. In fact, we don't see people running in droves to burn down the rain forest, in fact, quite the opposite is true. Do plants (including the rain forest) emit greenhouse gasses (CO2)?

Another theory of mine (and it is strictly a theory, absolutely *zero* research has been applied to proving or disproving this theory) is that as we develop more and more enclosed space, we are heating the planet more and more. Here's how it goes:

Air conditioners remove heat from the air. That fact is known and well documented. Consider all of the skyscrapers, office buildings, high-rises, and apartment buildings in modern society. Hot air rises, and cool air sinks. We all know about convection as a method of heat transfer. More energy is used to cool the upper spaces of a structure, since the heat is deposited there (it has nowhere else to go, after all!).

Consider this: as an air conditioner draws air into the system, passing it through the evaporator coil, it removes heat from the air by allowing the refrigerant to absorb its heat. As the refrigerant passes through the condenser coil, it removes this heat through conduction via the fins that are attached to the condenser coil and the fan that moves air over those fins. Where does that heated air go? Why, to the atmosphere.

*GRANTED* most of the heat is lost to radiation into space after dark. but the contribution to rising of average temperatures cannot (IMHO) be denied.

Also consider our refrigerators, freezers, beer coolers, water dispensers, etc. etc. These all have to vent heat from their respective cargoes somewhere, which is typically our homes/offices. That heat is then vented outside by our air conditioners.

It seems small I know, but the cumulative effect could be staggering (like every car in the U.S. getting 1/100 M.P.G. lower fuel economy). I theorize that these very systems contribute to global warming, and will continue to do so as we build more urban populous centers and continue to build higher into the sky. I welcome any contrary evidence.

Re:Freon isn't used in new cars!

[turbod]

Are you nuts? You need to take some heat pump theory, or just plain old thermodynamics.

Heat pumps are cheaper to run because they don't _create_ or _take_ any more energy than necessary to compress and move the fluid through the system. The temperature difference between the hot and cold side, combined with phase change properties in the fluid is what makes air conditioners so efficient.

You have to power the pump, but no more.

Compare a 20,000 BTU strip heater's power consumption with a 20,000 BTU heat pump.

Simply put, you need to check your facts before you post cheeky stupid comments.

Furthermore, the people who gave this award to these kids are most definitely graduates of the New Math way of thinking, ie., no point in obeying proven facts when we can make up what we want along the way to make older proven and better technology look bad by putting kids faces on it.

The educated know what New Math was really about --- but it has been corrupted into what we see here in this article, which is just plain stupidity and laziness about checking facts.

A Peltier Junction emits more heat than it moves, and fails the test for good technology at the scales where a compressor is not too much of a burden on the rest of a design. In addition, running a current drain system like a peltier junction off of 12Vs at the size required for a car (20,000 BTU or more), would require a alternator that would be so inefficient at out of rpm conditions, that twice the amount power wasted at the peltier, at least, would need to be wasted just to keep the stupid alternator rotating against the humongo bearings and cooling fan necessary to cool the damned thing.

Geez people, read the physic manuals before you make stupid assessments.

TurboD

Re:Freon isn't used in new cars!

[Hugonz]

In addition to being a MCSE, A+, etc. certified geek

Syntax error.

Re:Freon isn't used in new cars!

[ColaMan]

Let's see here....

Fatter alternator due to the giant amount of power consumed by a 40% efficient peltier. (Move 1 unit of heat with 2.5 units of power in)

VS

A/C compressor with a COP of 3 (move 3 units of heat for 1 unit of power in)

All that energy's got to come from somewhere. A typical car A/C is around 3-4kW. Or about 2kW of power to drive an A/C compressor. So, for a peltier equivalent, that's 10kW of electrical power from the alternator, driven from the engine, for the peltier array to get the same cooling effect.

I'll stick with compressor-driven A/C for now, thanks.

I keep toying with the idea of a twin ammonia-calcium chloride adsorption A/C, driven from the excess heat in the car exhaust. Heat one salt pack, release ammonia to condense in accumulator and tx valve , which then gets drawn to the other previously-heated-and-now cooling salt pack via an evaporator. When one pack is expended, direct hot exhaust gases to heat the other pack and continue. One of these days I'll get arond to it.

Re:Freon isn't used in new cars!

[arodland]

Simcop's joke was based on the grandparent's (I think) misuse of the word "efficiency". What the grandparent meant by 400% efficiency was that it moves 4 times as much heat than it emits itself -- but what "400% efficiency" means in the rest of the world is "takes one unit of energy as input, and outputs four units of energy" -- i.e. free energy.

But your grammar-deficient tirade was fun anyway.

Re:Freon isn't used in new cars!

[dbIII]

Not to nitpick, but the compression cycle of regular car AC is also powered by the motor

Yes, but it is far more energy efficient than a thermocouple driven in reverse. There's good reasons why this sort of thing wasn't done fifty years ago in this situation, but was done fifty years ago where space was tight and energy efficiency was not the issue. We have known about the physics involved and the materials used here for decades - peltier cooling has just come to prominance lately because it's a way to cut down on the number of moving parts and is getting into home computers.

These kids won against others because they did something others with knowlege knew was no big deal, and those that judged only looked at it superficially and thought it was a big deal.

It reminds me of a famous artist that developed an apparent way of dramaticly inproving fuel efficiency in internal combustion engines. By putting a spacer under the carby he optimised the motor to run while idling, dramaticly reducing the amount of fuel it used on a test bed - because the motor had been optimised to run at a specific load. He completely missed the point (that you want the motor to do something) and the press didn't realise either. The judges in this competition have also missed the point and gone for drama over utility.

Re:Freon isn't used in new cars!

[The_Dougster]

I keep toying with the idea of a twin ammonia-calcium chloride adsorption A/C

Ammonia might not be a good idea for Joe Lugnut the backyard mechanic. One good whiff of ammonia can actually kill you. Granted, its properties are a dream for refrigeration cycles, but there's a reason why it isn't used in consumer products.

Theoretically, one could stick reverse Peltiers all over the catalytic converter too, and use the thermoelectric generated power to run the cooling Peltiers. It would be grossly inefficient and pretty damn expensive, but it would basically give you free cooling with no power loss, similar to your idea above. I suppose the cost could be brought down by using cheaper Seebeck junctions at a trade-off in output power.

Re:Freon isn't used in new cars!

[ksheff]

The seemingly trivial change of having a light colour roof can substantially reduce air conditioning requirements (although it can also increase heating requirements).

That depends on what was done when changing the roofing materials. For a couple summers when I was in college, I had a job as commercial roofer. We would rip off the layers of tar and rocks that had built up over the years. In its place, polyurethane foam insulation would be sprayed down and then coated with a thick rubbery paint. We would normally see a big difference in how much the A/C units were running before we were even 1/2 way done. The cost savings due to using less energy all year round usually paid for the roofing in a couple years.

Re:Freon isn't used in new cars!

[CXI]

As a certified firefighter and geek, I can tell you that we certainly do not "use recovery equipment to remove refrigerants from cooling systems" when we arrive at an incident. Instead we are a little busy cutting people out of cars, extinguishing car fires, extinguishing house fires and the like. There are plenty of opportunities for this stuff to leak into the environment and if we do not have to use it, so much the better. BTW, does burning it turn it into a worse chemical?

Re:Freon isn't used in new cars!

[grgyle]

"...I welcome any contrary evidence..."

There are some basic physics nits to pick, I'd recommend reading up on guys like Carnot, Boyle, etc. When A/C coils pass heat to the outside surroundings, they are *not* creating a net increase in overall heat, they are simply moving existing heat from one place to another. The heat you feel coming off the back of your fridge is simply the heat that was contained in the interior of the unit. Once cool, the A/C only has to work to maintain a temperature difference, pushing already existing energy back to the outside--it doesn't continually pump heat willy-nilly into the atmosphere or create it from nowhere.

If left at rest, your fridge or office building would gradually warm as the energy migrates back in through conduction and convection, until everything is at equilibrium. Using your argument, if everyone turned off their A/C at once, we would risk global cooling as all of that outside heat gets sucked back into the buildings!

The only net heat increase happening is due to mechanical and electrical inefficiencies in the motor and compression cycle. All mechanical systems do this.

Re:Peltiers

[Anonymous Coward]

not so sure 400% is possible, captain science....

Since the article seems to be AWOL now...

[kevcol]

...let's go back in the Slashdot wayback machine and laugh at the last air conditioning article.

Re:Peltiers

[HermanAB]

An aircon using vapour change effects is a heat pump. Therefore, it can move more heat, than the amount of energy consumed to move the heat.

RSDA Press release

[mabinogi]

Here's the press release from the awards themselves, since TFA is dead.
(PDF)

The problem is the power supply from the Altenator

[GrpA]

Vapour phase airconditioning uses direct power from the engine, which often has an output of 100+ Kilowatts. More in a recent design.

No one notices a few Kilowatts disappearing. Except ricers.

Peltier devices come from the Altenator with an output capacity of around 1Kw or less, And most of that is used by Lights, Engine management etc... And for charging the battery

There's not a lot of electricity spare to run a Peltier based cooling device.

I've built something similar myself for a car once, but it only provides piped air - and didn't have to cool the whole cabin.

A 12 amp peltier device consumes a LOT of power... About 150 watts Not all cars can spare that much. And it doesn't cool much either.

I'm sorry I can't get the article up though. I really wanted to read it :(

Good on them though for experimenting :)

GrpA.

Re:Peltiers

[matt21811]

I could have made it more clear but your understanding and explanation are correct.

It is entirely possible to move 4 watts of heat energy out of the car with only 1 watt of electricity energy.

Re:Peltiers

[Anonymous Coward]

Too bad the car manufacturers can't put that extra efficiency back into the entire car. It would be great to turn on the a/c and get better gas mileage.

Re:Peltiers

[groman]

I've never seen one with efficiencies greater than 100%.


Oh, you haven't!? It's right here, next to my Orgone generator and universal translator.

Bad Link - better one

[WindBourne]

For the naysayers, it does say that it saves some 4 MPG over current ACs. IOW, it is more efficient.

New car electrical system

[ErikZ]

Wasn't there supposed to be a new 48v electrical system standard for all cars by now?

It would allow people to hook up better electronics to their vehicle, plus it would make the car more energy efficient. The example I heard was that instead of a belt driven AC unit, it would be electical.

The article I had read at the time stated that the standard would be implemented in 2005. Does anyone know about this?

Re:New car electrical system

[Technician]

It would allow people to hook up better electronics to their vehicle, plus it would make the car more energy efficient. The example I heard was that instead of a belt driven AC unit, it would be electical.

The article I had read at the time stated that the standard would be implemented in 2005. Does anyone know about this?

The only car I know of with an electric sealed compressor instead of a belt driven compressor is the 2005 Prius. It runs off the 400 volt hybrid battery, not the low voltage side of things. They didn't bother to stop at 48 volts.

No ozone depletion from hfc134a either

[name_already_taken]

Freon is trademark used for a variety of nonflammable gaseous or liquid fluorinated hydrocarbons which are no longer used as motor vehicle refrigerants.

The current refrigerant, hfc134a contains no chlorine (the ozone damaging part of R12) and has an ozone depletion potential of zero.

The idea of using Peltier devices is interesting, because there'd be no mechanical parts to wear out, or refrigerants to leak out, so the system should be much more reliable, but I thought Peltiers would require a huge amount of current to do as much cooling as a car A/C system delivers.

Re:No ozone depletion from hfc134a either

[alienw]

I thought Peltiers would require a huge amount of current to do as much cooling as a car A/C system delivers.

The car's electrical system is not suited to supplying significant amounts of power. A typical alternator tops out at about a kilowatt of power (80A or so). Due to the low voltage, ridiculously large currents are necessary.

Of course, a peltier is much less efficient than a compressor system. A compressor typically has a coefficient of performance (COP) of around 3, meaning that it removes 3 units of heat for every unit of supplied work. For peltiers, this value is around 0.4, which is a huge difference. Thus, the peltier would consume about 7x more energy to supply the same cooling capacity. This is the main reason cars don't use peltier A/Cs.

Re:No ozone depletion from hfc134a either

[UniverseIsADoughnut]

Yeah, I think people are missing simple facts here.

Pelters aren't very efficient.

Furthermore, if they were a good means of cooling things, we would use them for everything, but they don't thus why some kids build it, and corporations don't. If would be massively cheaper for them to use and have nothing but benefits. But they suck for the job, thats why they don't use them.

But people seam to be missing that part of this thing. I'm guessing all the articles are gone cause someone pointed out how bad a story it was.

Re:What an ironic twist.

[B4L1STA]

1) It's spelled "Mormons"
2) The trib moves the URL after it's no longer in the day's news
3) The trib isn't a Mormon paper. The Mormon paper is Deseret News (www.desnews.com)

But I have to admit, the poor Trib probably isn't used to getting slashdotted :)

In today's society...

[dpdawson]

More efficient?
Last longer?
Better for the environment?

It'll never catch on.

Re:Peltiers

[calidoscope]

Modern air conditioners have energy efficiencies approaching 400%.

Ummmm, I believe the term you want to use is "coefficient of performance" - which is how many watts of heat are transferred per watt of electrical power used. Also called an energy efficiency ratio.

Having said that, your point about the relative efficiencies of mechanical refrigeration units vs Peltier effect devices is correct. I have a ~18 cu ft fridge in my garage that uses less energy than a 1 cu ft Peltier cooler. Another point, the main focus for the development of Gadolinium refrigeration was to replace Peltier effect devices for small scale refrigeration needs.

Re:Peltiers

[arch_avaj]

Hmm, just reading my physics textbook a few hours ago about this topic, so I can clarify the obvious mistakes.

AC's have a Coefficient of Performance (COP) around 4-5 (or 400%-500%)
This is similar to effiency, but obviously not the same.

COP of a cooling device is measured as:
(Energy Removed from Cold Reservoir) / (Work Done on the device)

AC's don't cool, they just move the heat, and moving the heat doesn't require a lot more energy.

If this new device has higher efficience, it will have a similarily higher COP.

hey!

[austad]

I built one of these back in 1999 with some peltiers I ordered direct from a manufacturer, some old heatsinks, case fans, and bent tin sheets.

It fit in the window, just like a regular ac unit, but it didn't stick out at all. Basically, it was just two layers of heatsinks with the peltiers sandwiched in between. The hot side faced out the window and fans forced air on them to cool them, and the cool side faced inwards, with fans along the lower edge, a sheet of tin across the middle to make the air flow more over the fins, and an opening on top where it blew into the room.

It worked well for a small room. I suppose if I had the money at the time, I could have purchased some massively power hungry units and been able to get some crazy cooling power out of it. I probably still have it in a box somewhere.

Re:The problem is the power supply from the Altena

[RzUpAnmsCwrds]

"Vapour phase airconditioning uses direct power from the engine, which often has an output of 100+ Kilowatts. More in a recent design."

Not necessarily. The Toyota Prius, for example, uses an electric (144V AC) A/C compressor. Of course, it's the exception, not the rule. The Prius has a high-voltage battery system and a powerful inverter.

"A 12 amp peltier device consumes a LOT of power... About 150 watts Not all cars can spare that much. And it doesn't cool much either."

True. 150W is a lot to ask of a typical car. But a hybrid vehicle, like the Prius, can put out 5+ KW continuously without breaking a sweat.

"Good on them though for experimenting :)"

Well, if they have developed a peltier system that rivals an electric-powered vapor-phase system in efficency, their technology could very well find its way into future hybrid vehicles.

Bad pics at wilki

[bxbaser]

Certainly isnt what i was expecting

Re:The problem is the power supply from the Altena

[Frank T. Lofaro Jr.]

If no one notices a few kW disappearing due to A/C load other than ricers, than why do all modern cars disengage the A/C clutch when you go wide open throttle?

If you push the pedal to the floor with the A/C on you'll get your performance, at the cost of warmer air until you are done.

not as efficient...

[YesIAmAScript]

Peltiers do not work very well and are not as efficient as a phase-change (freon-type) system. You can prove this to yourself by buying a Peltier-based portable cooler at Target (they've been available for 20 years, search for "coolerator") and a $99 phase-change based cube fridge. The Peltier can barely get a six-pack to 35 (F), the cube fridge can make ice in a 1+ cubic-foot space.

This is just total bunk. The only way it saves energy is by not cooling as much.

Honestly, I think that the only threat to phase-change systems in small systems is sonic cooling. It could be more efficient, require less maintenance and have less environmental impact than a phrase-change system.

Evaporative systems are nice too, especially for large installations, but don't work for getting much below ambient.

Re:Peltiers

[Trogre]

If your goal is to generate heat, then yes you're right. But that's not what we're talking about.

Efficiency is a measure of how much useful energy you get out of a system compared with what you expend in doing so (contrast that with efficiacy).

Going by this a bar heater is 100% efficient, since any energy lost in the cable, etc is radiated as heat, which is useful energy for the purpose of heating a room.

Now heat pumps usually consume electricity to move heat from one sink to another. Once the cycle is started, the useful energy that is transferred is much greater than the energy you're expending to drive the pump. Therefore you're getting more energy out than you're consuming.

By consuming I of course mean converting energy from one form to another. And no this does not violate principles of thermodynamics since we're not converting the heat into another form.

cool things about this idea

[TRRosen]

1. works with electric cars

2. unit can be in passenger area and not in engine compartment

3. you could have several small units instead of one big one

4. flip the peltiers and you have a heater

5. no pulley being spun even when not in use

6. should be much lighter (although alternator would get bigger)

Re. Whatever ...

[Tjp($)pjT]

The new stuff is r-134.
The chips are semiconductor chips that when current is applied exhibit the peltier effect. One side gets warm, the other cooler. Essentially a solid state heat pump. No compressor, no liquid refrigerant needed. Instead just blow air over the device and its "cold sink" (same essentially as the expansion side air handler for a liquid refrigerant system in principle). So fewer moving parts. Especially the blasted compressor clutch assembly which in some cases makes it cheaper to replace the whole compressor with a rebuilt one than separate the clutch from it. The clutch causes the pulley to spin freely and not drive the compressor when cold is not demanded by the air temp controls, hopefully thermostats, but n ot always in cars.

in your disk drive analogy, it would be like coming up with a cheap flash drive that beat the specs for lifetime and cost to those spinning magnets you mentioned. It makes it last longer by eliminating wearing spinning parts that rub against each other roatating and moving up and down and up and down ... Not sure how the parent was maked "insightful" but there is no "lacks relevant technology background". Seriously though it is fascinating technology and along with heat pipes makes overclocking much less of a mess.

Re:Bad Link - better one No Just Bad Science

[truckaxle]

The students' research estimates their system would cut millions of pounds of hydrocarbons and nitrous oxides, and billions of pounds of carbon monoxide found in vehicle emissions. It also would increase gas mileage by four miles per gallon and hike horsepower by as much as 4 percent -- saving American drivers billions of dollars in annual gasoline costs.

Since when do they hand out awards for bad research at best or out-and-out lying. A peltier effect heat pump has a COP of around .3 and a typical R134a vapor compression AC has a COP of about 4. In other words, the existing AC systems are an order of magnitude more efficient. Now how are they going to increase the mileage by 4 and add more horsepower?

They would have to increase the size of the alternator several times to power this a peltier effect heat pump and you would have the unavoidable inefficiencies of converting mechanical energy into electrical to boot.

Why didn't they just mention that this thing runs off of cold fusion - and maybe they could get the University of Utah to endorse it ;(

"can't tell"?

[SuperBanana]

No one notices a few Kilowatts disappearing. Except ricers.

I'm sorry, but you're completely full of shit. Every time my A/C compressor clicks on while I'm driving, I can tell; I drive a manual, and if I'm paying enough attention, I can tell especially if revs are low (ie 2k).

Vapour phase airconditioning uses direct power from the engine, which often has an output of 100+ Kilowatts.

You are making the assumption that the engine produces its power evenly across the band, which is outright garbage. Most engines make much more horsepower at high engine speed; better engines tend to keep making that power the closer they approach redline (at high engine speeds, resistance in exhaust and intake paths kills horsepower because volumetric efficiency drops).

The engine will not make NEARLY as much power down at ranges people typically use; ie 2000 to 3000 RPMs. Example- the current Ford Mustang engine (no, I don't drive one- just the first chart I could find) makes 250HP at 5,000RPM+. At 2,500 RPM, it makes 100HP. The chart started at 2,500; numbers probably drop to 50HP at 2000. Suddenly, an AC compressor that uses several HP becomes a two-digit percentage of total engine output. While humans suck at absolute measurements, we can be -really- good at picking up on the finest relative differences.

Also, maximum claimed horsepower is often under ideal circumstances; ie cool air temps, engine cold/warm not at full operating temp, lightweight oil, and at sea level. It's also always on a perfectly functioning engine; ie fresh air cleaner, ignition bits are all new, perfect compression in all cylinders, etc.

Re:"can't tell"?

[GrpA]

>>No one notices a few Kilowatts disappearing. >>Except ricers. >I'm sorry, but you're completely full of shit. >Every time my A/C compressor clicks on while >I'm driving, I can tell; I drive a manual, and >if I'm paying enough attention, I can tell >especially if revs are low (ie 2k). That's because you're a ricer - I can tell from your response ;) (Tongue in cheek) Heh. Don't take that seriously. I'm not trying to start a flame war. And I apologise if you took exception to my generalisation. I'm quite familiar with HP and power ratings. AFAIK, the compressors are most efficient at low RPM, when there is plenty of torque available, so the effect would be even less.... However, for the sake of a quick post to an audience in which probably only about 1% of readers understand the relationship between torque, power and rpm, I thought I'd simplify. As for my experience and background with cars? Have a close look at my alias. GrpA.

Re:"can't tell"?

[Lumpy]

dude, your headlights use more power than the air conditioner in a modern car.

Turn off your headlights and your foglights (driving with them on makes people look like a dorks anyways) and you will have more than enough power restored for the AC.

My econobox that get's 42mpg went up to an average of 43mpg when I disabled the Daytime Running lights that was simply a diode that was turning on the headlamps when the car was running.

granted i drive highway speeds 909% of the time, but ther are many more power hogs in your car that are drawing more than the airconditioner does.

Re:"can't tell"?

[Vraeden]

"Turn off your headlights and your foglights (driving with them on makes people look like a dorks anyways) and you will have more than enough power restored for the AC."

Safety is more important than fashion. I'd rather see people drive with their lights on all the time than never (as they most often do).

Re:"can't tell"?

[gillbates]

dude, your headlights use more power than the air conditioner in a modern car.

Um, dude, you're wrong. Ford claims that the air conditioning compressor alone will use 25 HP on a hot day.

Your headlights, OTOH might use 10 or 20 amps. At 13.5 volts, thats 270 watts max. Or about 1/3 of one horsepower.

It's Actually 42v

[mrdrivel]

The new standard calls for 42v not 48.

It looks like there is the Toyota Crown Royal which uses 42v and a "new SUV from GM" that will use 42v as well. Source.

Re:Peltiers

[gerardrj]

I think what's being referred to is the heat the unit moves vs the heat it generates. Refrigerant based units rely on phase change of matter (gas to liquid to gas...) which requires the absorption and release of tremendous amounts of energy. The poster was not trying to say that the compressor was not wasting any energy as heat/noise/vibration.
If I recall my physics even somewhat correctly, the amount of energy it takes to convert a gram of water at 32F from solid to liquid state is 80 calories. That same amount of energy will then increase that same gram of water from 32F to 176F.

Stirling engines as heat exchangers?

[otis wildflower]

I wonder if Stirling engines could be used to convert heat from, say, HVAC coils, into usable power for a car? Or as an add-on to a turbo intercooler?

The Official R-12/R-134a/Freon Thread

[DasBub]

Let's set the record straight, here.

The noun "Freon" has a double meaning. Strictly speaking, it is the trademark name of refrigerant R-12, a single product of a specific formulation.

Due to its popularity it has become a sort of catch-all term used to describe an entire family of products. Much the same way that all couches can be called Chesterfields or all tissues can be called Kleenex, Freon can be used to describe a family of refrigerants.

As well all know, the actual Freon refrigerant, R-12, has been banned for a decade now. In this way, it is proper to say that no air conditioning unit in the US, Canada, etc., made since 1995 uses Freon.

The currently widespread refrigerant is R-134a, trademark name "Suva". It's chemically different from "Freon", but can be described as being part of the Freon family. This can make casual discussions a bit muddled as everyone argues whether or not Suva is Freon... Well, maybe I'm the only one having that type of casual discussion...

So, to make a short story long:

Freon is a Freon, Suva is a Freon, but Suva is not Freon. Got it?

Been there, done that

[gerardrj]

If you've had your hands on a peltier, you've probably sandwiched the thing between two heat sinks and two fans. One side is a heater, the other is a cooler. This is the exact method of operation of those in-car cooler/heater boxes you plug in to the cigarette lighter. These kids are simply scaling the idea up; instead of cooling a box in the car they're cooling the car.
There is nothing novel or innovative about this.

fRe:e peltier with rebate

[arbitraryaardvark]

Free peltier with rebate.
*informative, stupid*

Re:fRe:e peltier with rebate

[YouCanCallMeAl]

Amusing. I'm from South Dakota and I'm quite familiar with the Leonard Peltier story. I'm a bit surprised to see such a thing posted on Slashdot...

Re:Peltiers

[InvalidError]

Cooling efficiency is expressed with the "Coefficient of Performance" (COP), and is the ratio of displaced energy and input energy.

If you need 1kW (or 1kJ/s) to displace 10kW (10kJ/s), the COP is 10. This means the displaced energy is ten times as much as the energy used to move it.

Now, the catch with Peltier elements is that they have high COP only at very low power and small temperature difference, usually around 5-10% of the power rating and 10C temperature difference. Unless they are operated under these optimal constraints, their COP quickly drops under five. So, to produce a highly efficient TEC AC able to handle 1000W, one would need a 1kW TEC bank operated at ~80W. Considering that a TEC costs about $0.25 per rated watt, this efficient solution would cost over $250, roughly twice the price of an average room AC... and it gets worse: 1kW is barely enough to cool one square meter worth of solar heating, car and house windows have a much larger surface area total than that.

Note: a TEC's 100% rating is where the TEC barely manages to pump its own heat away from the cold side. TECs used for thermal regulation usually operate in the 30-50% range. The high-efficiency range is usually somewhere around 5% with COPs sometimes reaching over 15. For comparison, the theoretical limit for freon (and many substitutes) is around 16 but the best practical implementations only reach around 12.

Now, a typical room AC pumps from 5kW to 12kW with a temperature delta around 20C with a COP around 10. So, to beat the phase-change system's efficiency, the TEC solution would have to be beefed up by about 20X (10X the load, 2X the delta), bringing the cost around $5k, which is 20X as expensive as good classic AC.

Until they find materials that offer both better electrical conductivity and better thermal insulation to improve their overall performance (widen their sweet spot and move it up the power curve), TECs will remain a somewhat marginal cooling solution.

Yeah, right.

[AaronLawrence]

Seems to me like they have
a) bought a few cheap peltier chips
b) use fans to get a slightly cool breeze out of them
c) Assumed that this is the same as a car A/C unit

In fact car A/Cs have quite a large amount of cooling power, probably 100 times what they are producing.

As anyone with half a clue about this knows, Peltier devices are very INefficient, and are only useful in certain circumstances where the inefficiency doesn't matter (such as a really hot server chip where you don't care how much energy you waste, to get the heat out of it).

It's not like they've invented a new type of Peltier device; they openly say they bought some chips of Ebay.

It would be nice if they had discovered some new effect or configuration, but to me it sounds more like cluelessness and a bunch of equally clueless adults encouraging them. In reality cooling technology is very well understood.

Acoustic refrigeration?

[RubberDogBone]

I'd like to see more practical applications of acoustic refrigeration.

Apparently Ben and Jerry's is installing them in stores. Forget that. I want to be able to buy one at Home Depot so I don't have to keep buying crappy standard window air conditioners with their loud compressors.

troll

[shiftless]

I'm sorry, but you're completely full of shit. Every time my A/C compressor clicks on while I'm driving, I can tell; I drive a manual, and if I'm paying enough attention, I can tell especially if revs are low (ie 2k).

Of course you can tell when it clicks on. However, in 99% of the cars out there, the A/C does not effect driveability a noticeable amount.

This was the grandparent's point. So the air conditioner takes up, say, 5% of your engine power while you're cruising at a low RPMs. Big deal. Maybe the car feels a tad sluggish when accelerating at part throttle. That's OK, because when you floor it, the air conditioner clutch disengages and you have full engine power at your command.

I drive a Mustang with that engine, and while I can tell when the A/C clicks on, driveability is in no way impaired. If a person is worried about having a slow, underpowered car, why doesn't he get a car with a V8 or turbocharger?

Coolchips

[DiniZuli]

I gues they used regular peltier chips, invented a long time ago.
But I can't wait to these get to market.
They have build a prototype fab somewhere in eastern europe, are a little late on schedule because of lack of funding, but it still sounds prommising to me. They have been mentioned on Slashdot before.

Re:scientific method?

[SmittyTheBold]

No, it's not, because retards like the grandparent get the impression that something has been proven scientifically when it really hasn't.

King Bedevere does a better job of establishing a woman's witch-hood than those guys do "explaining" everyday occurrences.

[Addendum]

[SmittyTheBold]

Remember when the Discovery Channel was all about actual learning and knowledge?

On a related note, remember when MTV involved music?

And the Republican party was conservative?

Re:Peltiers

[Abm0raz]

I'm sure you meant C(oeffecient) O(f) P(erformance) and NOT efficency.

COP is defined as HEAT_RATE_REMOVED_FROM_COLD_RESEVIOR/WORK_RATE_REQ UIRED_TO_RUN_THE_PUMP
(also written as Q(dot)[L)/W(dot)[pump]). A simple thermodynamics course in Mechanical Engineering will tell you that THE maximum efficiency an refrigderator (reverse heat-pump, such as an air conditioner) can reach is T(L)/(T(H)-T(L)) where T(L) is the absolute* scale temperature of the low heat resevoir and T(H) is the absolute scale temperature level of the high heat resevoir. This value can exceed unity (1) and generally ranges from 2-5.

Efficiency of the heat pump or refridgerator is defined as USEFUL_WORK_PRODUCED/ENERGY_REQUIRED. For a refridgerator, this is written as Q(L)/W(in). Since Q(L) for a no-loss system is defined as Q(L)==Q(H)-W(in)** Through some equation manipulations shown on page 7-24 of the referenced book(see end of post) it's shown that Q(L)/Q(H) = T(L)/T(H) and that the efficency is defined as 1-T(L)/T(H) and that this value is always less than one as by definition of T(H) > T(L).

Appendices:
Source: Thermal-Fluid Sciences: An Integrated Approach 3rd ed, Dr. Stephen R. Turns Ph.D., 2003, Published by the Pennsylvania State Universit Department of Mechanical & Nuclear Engineering.

A heat pump/refridgerator is defined as a high temp resevior and a low temp resevior sufficently large that any instantanious heat added or subtracted by the system will not significantly affect their temperature. Between these reseviors is a pump that moves heat from the low temp to the high temp by performing work on the system. It receives the energy to perform the work from outside the system. The second law of thermodynamics*** says that because the natural entropy of the system would be an equalized temperature between the reseviors, the energy required to move heat the other direction must be greater than the actual energy moved (thus the efficency can never be greater than 1).

Q(dot)[L] => Rate heat is removed from low temp resevior
Q(dot)[H} => Rate heat is added to high temp resevior
W(dot)[pump] => Rate work is used by the pump
Q(L} => Heat removed low temp resevior
Q(H) => Heat added to high temp resevior
T(L) => Absolute temperature of the low temp resevior
T(H) => Absolute temperature of the high temp resevior
W(in) => Work required by the pump

* Absolute scale can be either Kelvin, Rankine, or any other linear proprietary temperature scale where there is no negative temp and that sets its lowest temperature at the temperature at which all molecular movbement stops (absolute zero)

** There is no such thing as a no-loss engine in real life. There will always be friction, drag, and/or head loss (for turbine/pump/fan driven air conditioners) or electrical resistance (for things such as peltier coolers). So the real equations is: Q(L)==Q(H)-W(in)-W(loss) where W(loss) is the total work lost overcoming internal forces such as drag, resitances, etc..) That W(loss) makes the maximum heat removed from the low temp resevior even less, thereby reducing the efficiency.

*** Among other things, it says: "Work can be converted entirely into heat. Heat cannot be converted entirely into work."

-Ab

ps. "Lisa, in this house, we obey the laws of thermodynamics!" -Homer Simpson

Many, Many, Many things wrong with the article!

[Ancient_Hacker]

Let's count the things tha are completely and verifiably wrong in the article:

• Peltiers are efficient-- NOT! They have an EER of way less than 1.0. A window air conditioner is above 10. End of discussion.
• There's no way to make them more efficient-- think-- they have their cold side right next to their hot side-- there's a lot of thermal conductivity there, effectively undoing a big percentage of the cooling.
• It's NOT more efficient to draw electrical power than to draw engine power. Somehow the kids think the alternator turns for free. Nope, it draws engine power just like the old AC, and as all defvices are less than 100% efficient, it has to be LESS efficient to use the power downstream from the alternator. { Minor caveat-- the alternator has the advantage of being able to put out more constant power-- direct drive from the engine to the compressor results in less AC (but not necessarily lower efficiency AC) available at slow engine speeds.)
• A typical auto AC puts out 30,000 to 50,000 BTUS/hr of cooling. A 1x1 inch peltier chip does about 150 BTU/hr at a cost of $9.95 on the surplus market. To duplicate a regular car AC would require 200 to 350 chips, $2000 to $3500. Plus a bunch more alternators, they'd need 1400 amps, about 20 alternators. Hard to fit them all under the hood.
• Peltiers do not last forever. They're prone to breakage due to cyclic stresses and degradation from humidity.

A REALLY bad aricle. The laws of thermodynamics rule.

Clueless kids

[wowbagger]

These kids ignore the facts that:

1. Peltiers are MUCH less efficient at moving heat than mechanical phase change coolers.
2. The electrical energy to drive the Peltiers will come from somewhere, namely the alternator.
3. The increased load on the alternator will in turn cause the alternator to place an increased load on the engine, reducing gas milage.

These kids didn't really test their system - as in, make measurements of fuel economy with the old system and with the new system in real conditions and see what the difference was. They just assumed that "If we get rid of the load from the compressor, we will save 10 HP that will save X amount of fuel" (ignoring the load from the alternator).

Now, if they had wanted to REALLY do something that would cool the vehicle without costing more gas, they would have mated an adsorption cooler to the exhaust manifold, and recovered the energy to run the cooling system from the waste heat discarded to the atmosphere.

A few points

[Muad'Dave]

• As has been mentioned, this isn't exactly a new invention or particularly innovative. As we've all seen from the patent office's behavior, something can be seen as innovative and blindingly obvious at the same time.
• Many posters have commented on the amount of power needed to run Peltier's - remember that in the not-too-distant future cars will have 48-52V electrical systems with alternators capable of much higher power output. Car's electrical systems are already taxed given the recent proliferation of nav systems, DVD players, laptop power outlets, etc., so the move to more powerful electrical systems is underway.

  Here are a few of the things that become possible with that kind of available power:

  1. Engines with electrically-actuated valve trains - no more camshaft, timing belt, rocker arms, pushrods, etc.
  2. Electrically powered power steering (as is done on my Mini Cooper S), eliminating that belt.
  3. Electrically powered A/C system
  4. The alternator either integrated in the block, or bolted directly to the crank. Imagine that - an engine with no belts!

• Wouldn't it be interesting to develop a cooling element that combined the Peltier effect and the Piezoelectric effect? Anchor one end and let the other flap, apply pulsed DC to it and you get cooling and a fan!

Mythbusters

[Steve_Jobs_HNIC]

Today's cars use more gas at highway speeds if only one window is down compared to the air conditioning.

Yeap, Mythbusters did prove this theory wrong. 2 SUV's were loaded up with 5 Gallons of gas and driven around the track. One had the AC on and windows rolled up, the other had the AC off and windows rolled down. If I'm not mistaken, The first test was inconclusive. However, the next test I believe proved this theory wrong. They decided to fully gas up the SUV's instead of trying to accurately measure and fill up only 5 Gallons. The test showed (and I'm not sure on these numbers) somewhere around a 5% to 10% loss of MPG on the AC SUV. While the AC SUV had to pull over, the windowed SUV kept on trucking!! So yeah, they busted that myth.

Re:Mythbusters

[Suidae]

The initial test was done by reading the output of one of SUVs on-board computers to determine how much air the engine was using. This test was done at 55MPH with windows up and AC on, and with windows down and AC off. The data indicated that the vehicle used slighly less air, and therefore less fuel, with the windows up and the AC on.

The next test was to be a 55MPH run around the race track to determine which of the test vehicles would run out a full tank of fuel first. Safety officials did not allow this because of concern over tire failure (and possible subsequent vehicle rollover) and possible driver fatigue (maintaining the concentration required to handle the vehicle for the 6-8 hours required for the test would be difficult). Instead the test was run at 45MPH with 5 gallons of fuel.

The power required by the AC on full is constant regardless of the engine speed. The effect of drag on the vehicle is dependent on the speed, and the nearly 20% reduction in speed may have eliminated the slight difference seen in the first test.

Also, the fuel was removed from the vehicles using a hand pump, and it was not shown that any effort was made to clear the fuel from the in-tank pump all the way to the fuel rail in the engine. It is possible that the two vehicles did not have the same amount of fuel.

They did not show that other conditions where checked, such as identical engine parameters (the computers in modern vehicles tune themselves depending on how they are driven, if the two SUVs were driven before the test they might have had different computer parameters, resulting in different fuel consumption rates).

In short, the experiment was very rough, and had little in the way of controls. It is likely that at low speeds it is better to have the windows down, and at high speeds it is better to have them up. Also, it is unlikely that the AC would be run at MAX the entire time, so there would be fuel savings there as well.

The episode was entertaining, and did mostly answer the question "Would a big SUV use more fuel driving at 45mph with the windows open and AC off, or with windows closed and driver shivering under continious MAX AC?"

To test more accurately would have required several trials of the same vehicle at several different speeds with an accurate flow meter on the fuel lines (both delivery and return lines). Throttle position at all times would have to be carefully controlled to avoid any serious variations in computer tuning. Trials would ideally be run in two opposite directions, similar to how land speed records are controlled.

Insurance scales horizontally

[sheldon]

That is... in order to have an efficient insurance system, you have to insure everybody.

Specifically, the more healhty people you have in the system, the less the overall cost is per capita.

This is why the US system fails, because we only worry about insurance if you aren't healthy.

Re:New AC

[praxis]

I wonder what technology (and fossil fuels) are used to compress the air. I wonder how often the air tank must be refilled. I see this as being a technology of a lot of future potential, but how effective is it today in terms of automobile range, environmental impact on compressing the air vs. environmental impact on burning biodiesel or other alternatives, etc. The site compares their PHEV with a convential battery driven electric motor, but they're short on some critical data points for comparision, which to me is a red flag...or at least orange.