Dry Ice in car in place of a/c. A bad idea?

July 17, 2007 7:44 PM

Will using dry ice in my car as a replacement for air conditioning kill me? Or my dog?

So I have no air conditioning in my car and it is bloody hot here in DC. I mean it's now 2230 and it's still 28C. Lunchtime today it was 34C, but after my car had been in the sun at lunchtime I could have sworn the steering wheel was more like 100C. I could barely touch it for the first 10 minutes.

The only cooling mechanism my car has is to open all the windows and drive quickly, as the air conditioning seems to have stopped working earlier in it's 16 year life span. Could putting a chunk of dry ice in the well of the car (ie where the passenger's feet go) cool it down sufficently?

Obviously I would need to keep the windows open, but CO2 is denser than air, right? So as long as I keep my head above the open window line, shouldn't I be ok? What about my dog, who also gets hot on long car journeys in her crate in the back (its what I would call an estate and what USians would call a wagon). How can I prevent the gas killing her?

How much would I need to use to cool the car (it's a Ford Taurus wagon)? What precautions would I need to take when buying the stuff (from Safeway I suppose: it's the only place I've ever seen it on sale).

Thanks for your help, the green.

T

posted by tonylord to travel & transportation (33 comments total)

Cheaper better safer to have your chiller serviced.
posted by hortense at 7:51 PM on July 17, 2007

I don't think it will work as well as you hope it might, and plenty of danger to go around. If the A/C system in your car is still largely there and the compressor hasn't seized, it might be a simple matter of a couple of new hoses and a recharge.
posted by maxwelton at 7:55 PM on July 17, 2007

Dry ice isn't cheap - it'd be less expensive in the long term to get the AC fixed.

Invest in some of those reflectors that you can stick onto your windows (or repaint your car in a lighter colour).

If you want to travel with an animal companion, maybe invest in some of those "blue ice" icepacks (or make friends with biological scientists who end up with several bazillion of them whenever buying stuff that gets shipped overnight). Take them out of the freezer, throw them in a cooler, leave in the back of the car and take out a few every so often.
posted by porpoise at 8:05 PM on July 17, 2007

I'd try a cigarette lighter powered fan or two first.
posted by crabintheocean at 8:06 PM on July 17, 2007

Ah, I should have said...I bought the car for $450 and I'm going back to Blighty in January.
The air con is of the old type, which apparently can't even be serviced any more without spending about $1000. Not so keen on that, hence the search for low tech/low price solutions...
posted by tonylord at 8:08 PM on July 17, 2007

Refilling you air conditioners coolant (which is most likely what needs to be fixed) isnt that expensive. The 100 dollars you will spend on dry ice can be spent on the AC.
posted by damn dirty ape at 8:08 PM on July 17, 2007

this is a joke, right? I worked as the produce buyer for a food co-op, and when our walk-in cooler's compressor failed we'd fill 'er up with dry ice until the repairman came. So, I can say from direct experience that, short of asphyxiating you, the effects of a carbon dioxide-enriched atmosphere can be insidious, and you're driving, for chrissakes! From OSHA: ". Concentrations of 10% (100,000 ppm) or more can produce unconsciousness or death. Lower concentrations may cause headache, sweating, rapid breathing, increased heartbeat, shortness of breath, dizziness, mental depression, visual disturbances or shaking. The seriousness of the latter symptoms is dependent on the concentration of carbon dioxide and the length of time the individual is exposed. The response to carbon dioxide inhalation varies greatly even in healthy normal individuals." And yes, it will kill the dog.
posted by pullayup at 8:11 PM on July 17, 2007

Pullayup.
No, not a joke. Thanks for your advice. Your comment was exactly what I was looking for. I didn't know that CO2 had those kind of effects.
No need to imply I'm a tool for asking.
posted by tonylord at 8:16 PM on July 17, 2007 [1 favorite]

Get yourself a cooling vest. Welders use them when they work in hot weather. They have pockets that you put ice packets in to keep your body temp at a comfortable level.
posted by any major dude at 8:18 PM on July 17, 2007

You can't cheaply replace the coolant - and you should not. Sounds like this is a car with old-fashioned, ozone-destroying freon. I have one, and I just suffer with it. I refuse to recharge the freon and don't care to replace the entire air-conditioner.

I second ice packs or bags of ice. If the fan on your car works, it might even blow some of the cooler air around.
posted by clarkstonian at 8:22 PM on July 17, 2007

I apologise, that came off as way more frantic than I intended, and I didn't mean to impugn your judgement. You can probably gather that I put myself (and probably my former co-workers, now that I think about it) in a medium-dangerous dry ice situation, and I think I kind of got that knee-jerk Voice of Experience reflex there. Boy, I'll make a great parent!
posted by pullayup at 8:29 PM on July 17, 2007

The steering wheel problem can be solved with a steering wheel cover or driving gloves. You shouldn't drive if the wheel is too hot to grasp.
posted by winston at 8:42 PM on July 17, 2007

Get one of those folding sunshades that goes in your front window, and throw a handtowel over your steering wheel for good measure. If your seats are vinyl, you'll want to do the same for anywhere anyone might be sitting.

Otherwise, open windows and a big dish of water for the pup.

I spent 26 years in Phoenix without ever owning a vehicle that had working a/c. It can be done.
posted by padraigin at 8:56 PM on July 17, 2007

I spent 26 years in Phoenix without ever owning a vehicle that had working a/c. It can be done.

posted by padraigin at 8:56 PM on July 17

I... bow down to your amazing tolerance for heat. Do you have super powers?

I grew up in Phoenix, and while it's a dry heat, so is an oven. I actually think Hell is cooler. Anyway, I drove a car for a year in Phoenix with no air conditioning, and I bought it in July. Which isn't even the hottest month there. Super. Awesome.

What I did:
1. Folding sunshade for front windows.
2. Shades for side windows and back windows, however feasible - you might have to cut down standard shades to fit.
3. Keep the side windows cracked a tiny bit while it's parked. Counterintuitive in both South Phoenix and DC, I know, but the key is keeping air flow happening in the parked vehicle. Otherwise it becomes like, well, an oven.
4. Cover all leather/pleather/vinyl surfaces that will touch your skin with some sort of cloth. It really helps. Plus, if you are sitting on a towel it will absorb all of the sexy sweat I'm sure you'll be producing.
5. Fans and airflow are your friends. Get the cigarette-lighter powered fans mentioned above and also immediately roll down all windows when you get in to get the air flow going.

I also second the giant bowl of water for the pup. I didn't transport a dog in my similarly-styled (and similarly impaired) car at the time, but I figure hydrating whoever or whatever is in the vehicle couldn't hurt.
posted by bedhead at 9:36 PM on July 17, 2007

First of all, you can replace older style R12 refrigerant with new, ozone friendly R134a refrigerant, although you may need to find and fix the source of any leaks for systems which have already lost their refrigerant, to have a repair that lasts. This isn't as big a problem on some systems, as it is on others.

If you have a 16 year old Taurus, your A/C was designed and originally delivered with R12 Freon refrigerant. Ford used R12 refrigerant through 1994, and R134a on everything after. To convert to R134a, you'd need to first find out if your system still contains any R12, and if it does, have the R12 removed. R12 is fairly valuable stuff, so some shops will do the removal for "free" keeping the recovered R12 for resale to recyclers. Most likely, however, your system developed a leak at some point, lost all its R12 refrigerant, and the system has been shut down ever since, on low coolant pressure limit switch trip.

Fixing the problem may be simple and inexpensive, or complicated and expensive. If it is something like a leaky high pressure hose, or (pretty common) an O-ring seal on a fitting, fixing the cause of the leak would be fairly cheap. Maybe as little as $50 to $100, with labor and R134a recharge. On the other hand, if the internal evaporator under the dash is leaking, you could be looking at several hundred dollars worth of labor to pull the dash apart, replace the evaporator coil, and re-assemble the dash. This would obviously be more than the worth of the vehicle.

But it's probably worth $45 for a do-it-yourself kit to try an initial recharge with R134a, at which time you can put in some UV dye, that will come out of any remaining leak points, and which you find with a UV test light. A 60 Watt UVA incandescent bulb you can get at most hardware stores for $8 is enough of a UV source to brilliantly illuminate leaks in the early evening. These kits are easy to use, even for someone with no mechanical knowledge, and limited tools (you may or may not need basic things like a pair of pliers or a crescent wrench to remove the caps on the compressor head fittings, to which you connect the kit's refrigerant gauge and lines). The kits often come with a CD that has videos of how to use the kit contents, and that explain automotive air-conditioning systems in simple terms.

What's probably going to happen, is that recharging the system with R134a will temporarily "fix" it, demonstrating that your compressor is still good, and that the system's controls work. After a few hours, however, the R134a you put in will leak away from the leak that let the original R12 out, and if you've put in the UV leak detection dye, you'll be able to see the places where the system is leaking with your UV lamp. With any luck, that will be hoses or O-ring seals in various fittings, which are easy and cheap to replace. So, you'll spend another $50 on replacement parts and more R134a, and you'll have airconditioning.

This is exactly what I did when I inherited a 1997 Dodge Intrepid with bad air conditioning, but in my case, I did have to replace the leaking evaporator coil in the car, which was a pain. But it could have as easily, or even more easily, been a 50 cent O-ring that caused my problem. The myth that all automotive air conditioning problems cost $1000 to fix just isn't true. Don't be dissuaded from trying simple things to fix or at least diagnose your system, until you know for sure what is wrong with it.

PLUS! A car with working air-conditioning in DC is worth well over $100 more than one with broken air-conditioning. So, if you've got 2 hours, and $50 to $100 to invest, you might fix your air-conditioning, without much risk to environment, or at least get a very good idea of exactly what's wrong, and whether it is worth further repairs. Stop by your local auto parts store on Saturday, and pickup a DIY recharge kit.

Even if you have to spend a few hundred dollars for repairs, the prospect of recouping much of that, in increased vehicle value at resale, ought to soften the economic blow a bit, and provide you a justification for fixing the air-conditioning. And further more, if you're going to be driving the car in DC in early fall and winter, remember that the air-conditioner has to be working for the windshield defrosting action to work. When you turn on the defrosting, its the air-conditioner that is drying the air before the heater core heats it to blow on the windshield, to clear it. Without a working air-conditioner, turning on defrosters can actually make a foggy windshield worse, by blowing warm, moist air on a cold windshield, where even more condensation builds up.
posted by paulsc at 9:43 PM on July 17, 2007 [8 favorites]

The Dog Whisperer says that dogs cool "bottom up", so putting a wet towel under your dog is a quick way to help them cool down. (Possibly not very feasible in a car, but then if it's a 450-dollar car, maybe it is.)
posted by thehmsbeagle at 10:04 PM on July 17, 2007

I tried freezing bottled water once, and placed the bottles all around the car. Finish 20% first to make room for the ice, otherwise the bottles will burst. Glass bottles not allowed! Stays frozen a long time, and lots of cool water is a real bonus on a hot day, especially since you have to carry water anyway on a long drive.
With a small bottle you can even wrap it in a cloth and slip it down the back of your shirt when you come back to the car... lovely cool feeling, and I didn't catch cold. Or wet a towel and wrap it around your neck.
posted by metaswell at 10:32 PM on July 17, 2007

Here's a thread from a couple days ago about keeping your car cool during the summer. Lots of window reflector suggestions.

How to keep car cool in heat?
posted by Jeff Howard at 10:39 PM on July 17, 2007

The thing is, you're going to need to keep your car so well ventilated to prevent the CO2 putting you to sleep that there won't be enough accumulated to actually do any cooling. The gas warms up pretty fast and any cold breeze you can feel, that's the stuff that will make you dozy while driving. So it's a total waste of money.

I'm telling you this from direct experience, drove five hours on Saturday with a 25L chilly bin full of dry ice in my car (actually, two of them each half full). My samples stayed nice and frozen but the car temperature didn't change noticeably beyond having the car windows open. It's winter here now but my experience fits with colleagues who have done the same trip in summer.

A car cover is your best bet and the one in the thread linked by Jeff Howard looks awesome.
posted by shelleycat at 1:03 AM on July 18, 2007

The presence of carbon dioxide in the air is how your body determines it needs to breath more (ie, the body detects that isn't getting enough oxygen not by looking at how much oxygen it is getting, but by looking at the CO2 level in the air it's breathing). This means that (unlike carbon monoxide) you should REALLY notice if any of the CO2 is getting into the air you're breathing, long before it becomes dangerous, but as pointed out above, this isn't necessarily enough if your life also depends on being able to maintain a distraction-free focus on the road.

I doubt the dry ice poses a direct threat to life, but the indirect danger (potential distraction while driving) is not to be sneezed at.


I'd put the dry ice in a long thin bag (ie large surface area per unit of volume), with a long hose leading out the window. This way, the bag keeps the car cool, and the CO2 , once gas, never gets into the air in the car, instead eventually just goes up the hose and out the window.
posted by -harlequin- at 2:56 AM on July 18, 2007

I have the same problem (minus the dog) and I do fine by keeping a bottle of water in the car which I occasionally use to wet my face. The wind from the window + the water = instant cool.

Keep your windows cracked a bit (like an inch) if you think that won't result in your car being stolen (probably nobody wants a $450 car anyway). It helps keep the temp down inside the car.
posted by joannemerriam at 3:30 AM on July 18, 2007

BTW, it's not like A/C usually helps much in the situation you describe of coming back to a baked car. It takes a while to get going, so it ends up blowing hot air for a bit, and the steering wheel and seats still take 5 minutes to cool down. I usually end up driving with the windows open anyway, because it's the fastest way to cycle all the hot air out of the car.
posted by smackfu at 6:12 AM on July 18, 2007

I wouldn't mess with large quantities of dry ice like that... a year ago at a supermarket I reached down into a bin of dry ice. I accidentally took a whiff of the air coming out of the top and nearly passed out right there on the spot.
posted by rolypolyman at 6:14 AM on July 18, 2007

Any hot steering wheel problems can be ameliorated by a steering wheel cover. I bought mine at target.

I live in D.C. and also transport dry ice from a safeway to my work (30 minutes) in my car. It does not significantly impact the temperature in my car. So I imagine it would be safe, but also ineffective.
posted by battlecj at 6:14 AM on July 18, 2007

Do NEVER use dry ice in your car as a substitute for AC! It is a Very Bad Idea, indeed.
posted by emd3737 at 8:34 AM on July 18, 2007

You can get a fan for your dog's crate at a pet store or you could get something other than a crate for your pooch. Please, Please, Please do not leave your dog in the car alone with the windows up. It can reach dangerous temps in your car very quickly.
posted by nimsey lou at 9:14 AM on July 18, 2007

you can also buy little fans that sit in the opening of a cracked window that run off solar power to keep your car from baking when it's parked. No idea how well they work though
posted by imaswinger at 12:06 PM on July 18, 2007

Thanks everyone for your help and advice. Seems like this is probably a waste of time.

Just to respond to a few points:
Nimsey_Lou: yes, obviously. Dog is never ever in the car when we are not. Pay attention, kids.

paulsc (and everyone else who said we should fix the aircon): I'll look into it, but I doubt it will be economical. I also doubt anyone will buy the car from us when we leave (it has Dip plates, which means it hasn't been MOT'd (or whatever the equivalent is in the US) since 2000).

Winston: again, obviously, I don't drive when the wheel is too hot to hold. The heat of the wheel isn't the main issue: I was using it illustratively.

battlecj: so it seems that even if I could get around the dangers, it wouldn't work. Sigh.
posted by tonylord at 3:22 PM on July 18, 2007

Maybe something like this Body Cooler Pet Mat would help, at least with your dog. And who knows? If it actually absorbs body heat, it might not make a bad seat cover for a human too.
posted by bchaplin at 5:14 PM on July 18, 2007

Being a bit more specific about dry ice's cooling effects, the cold just doesn't seem to spread all that well. I've also used dry ice sitting in a small polystyrene chilly bin in a warm room. The white 'smoke' coming off the ice was cool (that's the CO2 subliming), but the normal air next to it wasn't really noticeably colder and the room temp didn't change at all. I confirmed this with a temperature probe*. Given that the only cool area was within the CO2-rich areas and that's what you need to avoid while driving, this isn't going to help you at all in your car.

*it was the weekend, I was bored, curious and playing with the lab equipment
posted by shelleycat at 5:40 PM on July 18, 2007

Bit of a derail, but kind of important:

If you're driving around with a dog, you might be tempted to leave your canine companion in the car while you pop into the store for a few minutes. Don't. Even with the windows cracked, there's a really good chance of doggie death.
posted by Reggie Digest at 6:49 AM on July 19, 2007

Reggie:
umm...

Why are people assuming that I am a bad dog owner?
posted by tonylord at 8:49 AM on July 19, 2007

Jeez, my bad.

(It's nothing personal, btw; it's just that a lot of people -- particularly people from not-so-hot places who find themselves in Swelterville -- often don't think of a car as a solar oven until it's too late.)

WRT the steering wheel covers: In some places (I don't know about DC) it's illegal to drive with them on, since your grip isn't as good as if you were gripping the bare wheel.
posted by Reggie Digest at 8:31 AM on July 20, 2007