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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."
If you're having trouble seeing the article, try this: Google Cache
When all you have is a hammer, everybody looks like a Messiah.
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.
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.
Oh well, what the hell...
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.
Enjoy science fiction? "Turing Evolved" - AI, Mecha, Androids and rail-gun battles. What more could you want?
For the naysayers, it does say that it saves some 4 MPG over current ACs. IOW, it is more efficient.
I prefer the "u" in honour as it seems to be missing these days.
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.
Putting moderation advice in your
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
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.
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."
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.
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.
Trust the Computer. The Computer is your friend.
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.
.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?
;(
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
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
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.
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!
Javascript + Nintendo DSi = DSiCade
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.
What you reap is what you sow
Domestic fridges are the most reliable applicances in the home because they are built as a completely sealed unit.
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.
Do not look at laser with remaining good eye.
But Google's cache does have a copy.
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!)
- - - - - - - - - - - - - - - -
I take no responsibility for any spelling mistakes in the above post.
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.
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?
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!
We may experience some slight turbulence and then...explode. -Capt. Mal Reynolds
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