h a l f b a k e r yA riddle wrapped in a mystery inside a rich, flaky crust
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-sorry folks, some error lost my post, will adlib-
Hot-damn! Summer is really coming on here, and I for one am sick of getting into a hot car, and having to wait 5 minutes until the aircon had had a chance to cool it down. One option would be to have a larger, more powerful air conditioner, but
that smacks of inefficiency, as it would rarely be running at capacity.
Instead, have a tank of liquid N2, coupled to a small high pressure compressor that trickle refills the tank while the car is running. When you get in the car and turn on the aircon, and the climate control detects that the temperature is high enough (and you’ve disabled the interlock, of course), WHOOOSH. The windows go down a smidgeon, and N2 is dumped into the cabin. As it changes phase, the N2 cools everything down. As soon as the fog clears, drive away, cool and comfortable.
{I’m quite sure one could calibrate the system to not freeze the occupants. It’s as simple as metering the liquid N2 through several outlets dispersed about the cabin, with special nozzles to maximise the cooling effect. Ultimately, you probably don't need a great capacity of N2, either.}
Liquid Air
http://en.wikipedia.org/wiki/Liquid_air
For 21 Quest. Aw, dang, don't you just hate it when you're wrong? [DrCurry, Oct 22 2006]
Air Exchanger
Air_20exchanger
Why liquefy? [Aq_Bi, Oct 22 2006]
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Annotation:
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You realize that you will then suffocate? Unless you use liquid air, as opposed to liquid nitrogen, this falls into the realms of Very Bad Technology. |
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How cold do you need your car to be? |
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The open windows will simply make it easier for the piped nitrogen to push out the breathable air. Objection remains. |
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(If you doubt, go search for the stories of entire villages being wiped out by puddles of carbon dioxide. In those cases, being in the open air was not protection enough.) |
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what about liquid air then? |
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Also, much of the interior of the car is made from good insulators. If these have had an hour of being parked in the hot sun to heat up, being exposed to very cold vapourising nitrogen for a few seconds won't cool them down. So you'll get in your car, sit on the hot velour seat, burn your hands on the hot plastic steering wheel, and then your hand will freeze to the ice-cold metal handbrake lever. |
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In addition to the suffocation problem: |
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- your small compressor has to produces about 800.000 psi. |
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- a tank under high pressure is dangerous |
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- probably less efficient then an oversized a/c. |
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21Q: ahem, see link. By your reasoning, we couldn't mix margaritas (since alcohol and water have different boiling points). |
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Could you inject liquid nitrous oxide instead? haha. |
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if you insist on using LN2 then don't run it directly through the passenger compartment; run it through holes/pipes in the frame and cool that and use it to cool outside air coming in. (Don't blow it through the defrost or you'll be replacing your windshield. |
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Bun for anything that cools the car down
immediately. |
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// I for one am sick of ... having to wait 5 minutes // |
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Let us all join you in your courageous fight against momentary discomfort. |
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I see the heat as built in damnation for using cars at all. So, avoiding this necessary evil feels a bit foolish. That being said, it's never stopped us before. [+] |
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Also, you know [Curry et al.], Air is 79% nitrogen. What makes you think having a dash of the pure stuff is going to lead to all this drastic suffocation? CO2 pools because it's heavier than air. N2 will quickly diffuse any air that's presented, especially if there's a large temperature differential. Please don't make me open up my old fluid dynamics texts to get relative diffusivities of N2 and CO2 with air... I'll do it! |
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Let me step in just to point out that [DC]'s link doesn't actually tell us that N2 and O2 will evaporate at the same temperature, only that their liquid states can be mixed. What will happen is that the O2 will boil off first, giving you a headache and dry throat, then the N2 will boil off. Whether there will still be enough O2 around to keep you alive is left as an exercise for the reader. |
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Not if you were using an aerosol nozzle. There would be no distinguishable O2 first, then N2 procession - you aerosol a mix of liquid N2 and O@ and it'll all flash off at the same time. |
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//O2 will boil off first// Other way around, Shirley? |
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True enough [custard]. [spider] Yes. |
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