Arctic Air Conditioner

[DonMuncy]

I'm not totally convinced about the danger of dry ice, as it relates to air quality. Naturally, any change in the components of the air in the cabin makes a difference. But I am not certain about the quantities involved. As I understand it, one pound of dry ice sublimates into about 1 cubic meter of CO2. When we breathe in air, we breathe out CO2. I don't know those volumes. Depending on how wide open we have the vents in our cabin, we are diluting the amounts of all the stuff in the cabin. Overall, I have no idea how that affects the O2 available in the cabin.

We need someone with extra time on their hands to load up a couple of pounds of dry ice in an open container, go up and measure their O2 level with an oximeter , and check the same without the dry ice.

[rbridges]

Just thinking out loud. O2 is a commodity at altitude. Anything that drops the percentage isn't going to help. At what point does it become a problem, I don't know. As someone mentioned, dry ice sublimates and doesn't have much of a liquid state. Can't see how that would help with the Ice cooler air conditioners.

[M20F]

Quest Diagnostics has a fleet of King Airs that they run samples around the country with. They used to pack their samples in Dry Ice. Several pilots got loopy and CFIT

A bit different in a pressurized plane. Dry ice sublimating in a closed vessel like a cooler, pressurized compartment, etc. is bad. In a little GA plane it is just going to exhaust out the vents as Don suggests.

[Hank]

I'm not totally convinced about the danger of dry ice, as it relates to air quality. Naturally, any change in the components of the air in the cabin makes a difference. But I am not certain about the quantities involved. As I understand it, one pound of dry ice sublimates into about 1 cubic meter of CO2. When we breathe in air, we breathe out CO2. I don't know those volumes. Depending on how wide open we have the vents in our cabin, we are diluting the amounts of all the stuff in the cabin. Overall, I have no idea how that affects the O2 available in the cabin.

We need someone with extra time on their hands to load up a couple of pounds of dry ice in an open container, go up and measure their O2 level with an oximeter , and check the same without the dry ice.

Yes, we exhale CO2 with every breath, but not very much. The atmosphere is about 0.04% CO2. As for vents, I close most of mine whenever I run cabin heat, can't see keeping them open and sucking in hot air while I'm running the AC--I don't do that in the car, either.

Let's say that our cabin averages 3' wide, 3' tall and is 8' long (but it's smaller than that). That's 72 cubic feet of air. A standard atmosphere (remember, sea level, 59°F/15°C?) has density of 0.0765 lb/ft3. Doing the math, that gives 5-1/2 lb of AIR, or 0.22 lb CO2 (except it's higher, CO2 is heavier than N2 and O2 which make up 98% of the air we breathe). Do you really want to sublimate 10 lb of CO2 inside your plane? Take two hours, that's 5lb per hour. Vents closed, assume the air refreshes once a minute or 60 times per hour. Five pounds divided by 60 is 0.083 lb of extra CO2 in the plane for two hours, assuming it all blows out the vents every minute (which it won't).

So the amount of CO2 will rise from 0.22 to 0.30 lb, a 36% increase, and this is a minimum value; I would expect air flow through the plane to be a third of this amount, and for air volume to be less by an amount varying by Mooney model. Any further analysis is hampered by my simple numbers, as everything is reported in parts per million and uses molecular weight. Even CO2 meters use PPM. So 100 ppm is equal to 0.01%, and we are talking a minimum increase of 0.04 + 36% = 0.054 which is around 140 PPM. What would you do if your CO2 detector in the plane or your house read 140 ppm?

Who wants to fly with 140 PPM CO2 in their plane, raise your hands . . .

[DonMuncy]

Hank,

You certainly have done more calculations than I am capable of. The only question I have is about the CO2 detector. I don't know that I have ever seen one. I have a carbon monoxide (CO) detector.

Do you have any information about the allowable amounts of CO2.

Mind you, I am not advocating using dry ice. I just don't know whether anyone has information about the hazard levels.

[RobertGary1]

How do you run your heat without the vent open? On my Mooney you wouldn't get any heat if you don't have the vent push air through the exchanger.

-Robert

[Hank]

I generally run more Cabin Vent than I do Cabin Heat, to keep from melting. But the roof scoop is closed, the eyeball vents in both foot wells are closed, and the large vent opening under the throttle quadrant is mostly closed.

[Hank]

Hank,

You certainly have done more calculations than I am capable of. The only question I have is about the CO2 detector. I don't know that I have ever seen one. I have a carbon monoxide (CO) detector.

Do you have any information about the allowable amounts of CO2.

Mind you, I am not advocating using dry ice. I just don't know whether anyone has information about the hazard levels.

Oops, my bad! I don't have a clue, but I'm sure OSHA has some limits. They have limits for everything, and classify both Oxygen and Water as extremely hazardous chemicals. Too much water will kill you, and of course O2 is extremely combustible. We just won't live very long without some of both . . .

[RobertGary1]

Dihydrogen Monoxide is a silent killer and found in high quantities in the Arctic system. Dhmo.org.

-Robert

[DonMuncy]

Robert,

A smiley face might be in order. Someone may spend time worrying about this before figuring it out.

[RobertGary1]

Opps. Did someone?

[DonMuncy]

Not if they know what Dihydrogen Monoxide is.

[Marauder]

Not if they know what Dihydrogen Monoxide is.

Cut it out Don! You're making me thirsty!

Sent from my iPad using Tapatalk

[RobertGary1]

I don't know if I've ever flown my plane with the main vent closed but I suspect the rate of turn over for air is pretty high. Try this. Drop a nasty fart in the cockpit and see how long it lingers. I bet it's pretty quick. I know the flow through the full time rear vents under the seat is pretty high.

-Robert

[Tom]

....Take two hours, that's 5lb per hour. Vents closed, assume the air refreshes once a minute or 60 times per hour. Five pounds divided by 60 is 0.083 lb of extra CO2 in the plane for two hours, assuming it all blows out the vents every minute (which it won't)..,

Who wants to fly with 140 PPM CO2 in their plane, raise your hands . . .

 

FAA to the rescue:  https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0CC4QFjADahUKEwjL5reOxJjHAhXIvBQKHUyGDio&url=http%3A%2F%2Fwww.researchgate.net%2Fpublictopics.PublicPostFileLoader.html%3Fid%3D55284358ef9713b4478b459d%26key%3Dd802e980-a6c4-4c40-9457-496a5dda8375&ei=3nXFVcv_LMj5UsyMutAC&usg=AFQjCNHk2GA5kutJudOmMX4hFljixZqqog&sig2=nAHjTi0YNCheH5glFW_NlA&bvm=bv.99804247,d.d24

 

Thoughts:

1) No one is going to use dry ice anyways for the purpose being discussed

2) 5000 ppm is the cut-off limit for CO2

3) Referenced cases of aviation CO2 poisoning relate to circumstances where CO2 was allowed to accumulate in a fuselage where the symptoms were noticed prior to take-off

4) Unlike CO poisoning, CO2 poisoning does not confer long-term damage to tissue unless there is a CFIT

5) Seemingly all unpressurized aircraft leak like sieves such that accumulation of CO2 wouldn't be a problem once there is air flow through the cabin vents

6)  I'm not an HVAC guy, but sublimating dry ice as a means to cool a cabin doesn't make sense as it doesn't sublimate fast enough without the use of water to cool things down

[carusoam]

David,

Boat supply company for small bilge pump and bilge fan/vent.

Car parts store for heat exchangers, battery, wires and fuses.

Camping supply company for cooler.

The challenge with scaling down the size of the device is, the cabin size doesn't change because there is only one person...

Airflow will be the same keeping the fan the same.

Heat exchange will be the same keeping the heat exchanger the same.

Water flow will be the same keeping the pump the same.

Scaling back the airflow, the exchanger and the pump would work well in the northern latitudes. Not so much in TX.

The nice thing about the pre-engineered and built ones is they have a history of working well in our airplanes in different latitudes. iPhone apps, remote controls and sensors, and other nice to have stuff...

The challenges of doing it yourself...re-doing it yourself...

The one advantage of keeping the internal hardware the same. You can cut the volume of ice you are going to use in half or more.

The ice volume appears to be about 1/2 the total volume of the cooler.

It may be cooler

[N601RX]

I've saw some very small ones that don't blow air, they are in the form of a slip on seat cover or vest that circulates the cool water through small tubes.

[PaulB]

So I've used the one that was given to me now and it works ok but it really is a hassle getting in and out of the plane.  My thought is to convert a bucket with a fan blowing directly down through the lid and vents on the sides of the buckets.  I plan on putting ice packs inside the bucket.  I imagine this will work and take up less space.  May not cool as long but really all I need it for is about 10 minutes or so on the ground.

[carusoam]

David,

Both companies are run by very personable guys.

They both communicate well using email.

They both took customer ideas and put them into later production.

If you have an idea that works for you, it may work well for them too.

Send them your dimensions, see what they say...?

Best regards,

-a-

[Yetti]

http://www.amazon.com/New-RULE-IN-LINE-BILGE-BLOWER-12V/dp/B001K914XW

 

http://www.amazon.com/Spectra-Premium-94553-Heater-Chevrolet/dp/B004LGWEG2/ref=sr_1_2?ie=UTF8&qid=1439134263&sr=8-2&keywords=heater+core

 

http://www.amazon.com/Shoreline-Marine-Bilge-Pump-600/dp/B004LRBI9A/ref=sr_1_3?s=boating-water-sports&ie=UTF8&qid=1439134344&sr=1-3&keywords=bilge+pump

 

The rest of the parts can be sourced from homer dan

[Yetti]

With a bucket you would have to mount the heat exchanger vertical, which would then get into your ice carrying capacity.  Also would need to do duct work and only use the heat exchanger vs airflow across the top of the ice.  Would still work.

[Tom]

I'm not in the market for this stuff, but what about using one of the newer self-contained cooling vests?  Perfect if you just need the cooling benefit until climbing to altitude.  The different manufactures routinely report 2+ hours at 59 degrees...this should be more than ample.  Might come in useful at other times...working in the heat around the house, visits to the in-laws, church, etc.  http://www.coolvest.com/
 

[carusoam]

A sign of too many competing devices for people’s needs and wallets…

The iceboxes work really well… for low dollars…

The installed electric powered AC works great… similar to an automotive unit in simplicity to operate…

The engine driven units are nice when bought at the time of plane construction…

 

See if anything has changed since…

Best regards,

-a-

 

 

[A64Pilot]

I just popped into the last page of this.

‘But on the C02 thing, it only takes a little to kill you, ask any re-breather diver, it’s not that the CO2 displaces O2, it’s the CO2 causes loss of consciousness, seizures etc. which leads to a rebreather diver drowning of course and not so good for a pilot either.

If memory serves less than 5% CO2 and your worthless, 7% or so and it’s lights out.

[philiplane]

On 8/8/2021 at 11:13 PM, philip_g said:

Any further discussion of the Arctic air REAL AC units? Anyone else pick one up recently?

 

This is the air conditioning unit. Not a cooler with ice. This thread is like 3 posts about the AC and 400 about coolers 

I have installed six of them in various planes. I've had one in my Aztec for four years in South Florida. Also have a spare ice type cooler I lend out to visiting friends from the north.