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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[j00bar]

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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.

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: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

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.

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 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: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:/.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: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!

[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:/.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.

Re:/.ed

[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

[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!)