I have a air "conditioner" for my airplane, its an

You want to add more thermal capacity to the resevoir. What you really want to do is use salted ice below zero. As far as I know, water has one of the best non-toxic and most cost effective heat capacities. Find out for yourself if things like liquor have a greater thermal capacity; stay cold for longer.

More water, ice, and even frozen water bottles to further the longevity.

You might also want to look into thermoelectric cooling, TEC plates, and peltier plates (all the same thing). Basically it uses electricity to make one side of a plate super cold. The other side gets hot. The vary from 12v to 24v which your plane should be fine powering; but they do draw a little bit of amperage.

Ice frozen in the bottom of an ice chest set to its coldest setting will stay colder longer than ice frozen in the family freezer. Remember, it freezes at 0C, but once it has changed to a solid state it will continue to drop in temperature.

Basically you want to take any room temperature liquid mass, mass and therfore weight is a factor, and drop it's temperature below its freezing point as low as you can. You will pull out a few more minutes of cooling because it has to change states to get back to room temperature. This is why water works pretty well.

If it's dry enough in the plane at altitude then you could get more cooling g by making a secondary evap cooler. At that point is may be worth the weight of a scavenged single room ac and battery.

Last suggestion is to put a drain on the box. Heat transfers to the water more readily than the air so you're heating part of the ice with heat that's already been removed from the air.

>>1057576
Best I can do right now is frozen milk jugs of ice bricks. Plastic is slower to let the cold out than metal so thats a trade of coldness for length but I could do metal too.

This thing works by circulating water thru a pump though (there has to be some liquid water with the ice) so salt will fuck it up that way, probably mess up the coil too. Would salt in the milk jugs work though?

>>1057581
Yeah I could get a freezer than gets super cold. it better be more than a few minutes though, i dont want to pay legit money on powering a super cold freezer for no reason.

problem with a regular A/C unit is that it needs to vent hot air out somewhere. that would mean cutting holes in planes. thats why this seemingly goofy gizmo is touted as 'a $600 solution to a $25,000 problem'

as far as a drain, i wouldnt need one (if i wanted to i'd just let the jugs thaw and run just the fans) but the fans themselves dont do much. its the pump that really makes cold, and the pump needs some liquid.

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>>1057594
Have you tried pic related? It would follow the principles I laid out >>1057581

Air travels directly over the cold mass and out which is more efficient than converting the energy a few time. It's pretty cheap to find out if it works better than the thing you have already.

Also, if you bought a deep freezing chest freezer you can save a ton of money by buying half a cow, a couple chickens, and a pig or 2 from a local butcher. If you are flying a plane, you need to find cost savings where you can.

I'm not a pilot but most of my friends are, what kind of plane do you fly?

>>1057602
yeah that thing would pump moisture into the cabin, cant have that. thats why the op pic unit has a heat exchanger with a coil

i fly a cessna 210, do aerial photos and stuff like that. its brutal in the summer.

>>1057576
Peltier is an interesting idea. Same issue as a/c with the heat dissipation, but would be easier to transfer heat from a plate than air.
Cesna is aluminum shell- stick the peltier onto it, warms up the fuselage, passing air cools it off.

Deep freezer makes the most sense.
It will be more than a couple extra minutes.
30°>60°
Vs
0°>30°>60°
Takes as much energy transfer to warm something from 0-30 as it does for 30-60.

>>1057566
"Bad case of the crashes. Lol, good call. I'd freeze largest containers u can. Like gallon jugs. They last near all day in my water jug. Bonus, if u get a case of the crashes u have plenty of drinking water. Keep her in the air op. Pics of plane?

Crack a window, cut that plexiglass up. Bugsmashers these days...

Add a shit ton of salt to the ice

>>1057812
Probably not a good idea to have saltwater in a plane in case it spills ? All sorts of long term corrosion problems might come up...

Why can't you just fly higher? Legit question, I'm not being a cheeky cunt.

>>1057566
Can't you just open a window?

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>>1057566
adding salt doesn't really do much except slightly increasing the thermal capacity. Lowering the thaw point by adding salt doesn't magically make energy disappear in a black hole. It just makes the ice thaw at a lower temperature, so it might actually end up at room temperature faster since the delta T at phase change is higher.

The only option you got is choosing a material with high thermal capacity (water is a good bet, here's a list of some other generic things you could use http://www.engineeringtoolbox.com/specific-heat-fluids-d_151.html) and cooling it down as hard as possible before dropping it in your box.

What would probably work is adding an additive to your water that doesn't damage the pump/heat exchange unit/piping (acetic acid?) that lowers the thaw point and increases its thermal capacity. Then cool it down to the lowest temperature you can manage (probably use dry ice to cool your water in a styrofoam box) and make sure it partially freezes.

>>1057821
You realize they make boats out of aluminum without any coating right?

>>1057566
Fly higher, where air is colder, open window?

FYI, I've made and used devices using ice water. They are only good for spot cooling, not for cooling a room or cockpit in this case. So, if you can have it blowing air directly on you then go ahead. If you can't then the results won't be nearly as good.

>>1057905
I looked and found the marketing ad, and it makes sense why these things exist. I've never flown a plane but their marketing ad talked about preflight checks, waiting on tarmac for 90 mins, then finally taking off and getting to colder weather 30 mins later all in 100 degree southern heat.

Apparently plane AC systems are $20,000?

>>1057566
Buy dry ice instead of water ice. You can get it many locations and it'll last for days.

>>1057895
But they don't have two different metals on boats touch because salt water turns them into a battery. Aircraft do not need to conform to these standards and get they have say a steel bolt in an nickle/aluminium frame. Causing very expensive corrosion.

>>1057781
Yeah, frozen jugs is the best I've got right now.

Kinda thinking about trying to find the liquid/gel they put in those lunch packs and maybe just buy it bulk and put that stuff in milk jugs?

I actually dont have any pics lol but its nothing fancy, standard cessna 210M. I also fly a 340 and 414 occasionally.

>>1057805
>crack a window
i shoot photos out a window, its wide open all the time when I'm shooting, but at 120-140 mph I'm way, way back on the throttle and when its 90º even that doesn't help. If I'm moving from site to site I'm not going as slow as I can lol, and the window open at 200mph is kinda ridic.

As far as cutting a hole, modifying an airplane is one of the most arduous and expensive hassles a human can undertake in this lifetime. A simple plastic window costs about $900 to replace (thats not modify, thats just to replace)

>>1057812
read the previous posts. its a pump system, salt ruins the pump and coils the water is pumped through. besides, salt just lowers the freezing temp, it doesnt make ice colder.

>>1057824
You lose about 4.4º per 1000' so starting at 90º its a looong time to get from a non-running plane to say 10k', and thats only the temp outside, not inside the oven-like aluminumbox that is an airplane. Even so, most people just tough it out. The thing is, the flying I do (when I get to a site) is down low and slow, so for example I can be over chicago shooting 7-10 sites for like 2 hours, by which time I am absolutely drenched. And then I have to either land and go do more work, or fly an hour and change home (or to another area for more sites) it can be hours, if at all, i ever reach cooler air

>>1057836
>adding additives
yes, this is what I was curious about, if such a thing existed. Now of course, I have to weigh the benefits of adding time (10 min? no... 60? yes) to the 'melt' against how much effort it takes to get that extra time... dealing with dry ice might not be worth it.

But thats good info, I''ll look into it

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>>1057905
>>1057907
I think you're the same person but yeah you got it, sitting around at low alt for a long time is brutal on hot days. and yeah an installed AC system is stupid expensive, and costs a significant amount of available load carrying ability that you cant remove. the little ice chest comes out if I dont need it (though the 210 is quite the hauler, its almost never an issue)

aaand... no one wants to be in a plane when youre going 180mph with the window open lol. gets to be a tad breezy. and loud. and slows me down. etc.

but more to the point, the work i do has me down low, away from cool air at higher altitudes (when Im traveling to a site I go high, but when i get to a site i'm down low, and can be down there for a long time)

>>1057913
why are you trying to kill me. what did I do to you?

>>1057919
>Aircraft do not need to conform to these standards
>implying boats have a higher standard of anti-corrosion issues than a boat
hillary us, comrade. you are of humor.

---------
pic taken today (not with my work cam, just cell phone)

>>1058025
Not the same guy, but yeah, you want a peltier cooling plate. You could trick it out to add a CPU cooler to blow air. These things can frost over if left on long enough, simple enough 12v or 24v which you already have. If you own the plane, its a matter of wiring it up.

>>1058034
how/where do you exhaust the heat though?

>>1058063
press the hot side to the exterior aluminum skin of the body.

>>1057566
get denatured alcohol from the hardware store.

get dry ice.

put the dry ice into alcohol until extremely cold

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>>1058025
>why are you trying to kill me. what did I do to you?


Do you not exchange air from the outside? The volume of air inside an aircraft wouldn't last a person long.

>>1057566
MFW I was studying aviation, a month after I started my mom fell ill and 5 months later she passed away. I had a depression that lasted about year and a half, and right now there's a gang of people in my neighborhood that is actively organizing to kill me.
Good times tho, I enjoyed the experience.

>>1058114
Did you kill your mother?

>>1058018
well, you got to figure out what your pump/heat exchanger/piping is actually out of so we can possibly tell you what additives might work without fucking it up. Acetic acid might be fine, it's not really that agressive. Every usual metal but copper should be OK with it.

60% acetic acid has a thawpoint of about -26°C. If you can get it below that and make sure that it freezes to a large degree it should last quite a bit longer than normal ice, simply due to the quite reasonably higher thermal capacity and due to the lower thaw point.

An other option might be to ghetto mod your system so that you pump a liquid with really low thawpoint through pump and heat exchanger and some piping you put into an insulated box which you fill with a metal block/solid material with high thermal capacity that you supercool before you use it (liquid nitrogen is cheap and gets it plenty cold). That is probably the best option you got unless you are willing to drill a hole into your plane to vent gasses of evaporating liquid nitrogen/sublimating dry ice/CO2.

Is a piece of pipe exhausting nitrogen/CO2 out of the plane really out of question? Liquid nitrogen would be your best bet because it is already 70% of the air you breathe, making it really difficult to get the concentration high enough to be dangerous. A simply air quality meter for about a hundred bucks will also warn you if nitrogen/CO2/whatever concentrations get above TLV or to dangerous levels so you can open a window way before you risk passing out. I doubt that liquid nitrogen would be a problem at all, even without exhaust pipe, but i definetly wouldnt take the risk, at least not without air sampling tool.

>>1058077
this is how you start fires and your wing melts off and you plummet to the ground (face first because I want to make sure I dont feel this)

i would need to know how far the heat radiates, tested in hottest conditions, to know it wouldnt melt something that shouldnt be melted, weaken something that should remain strong, or vaporize something that should be not vapor.

>>1058104
45-50 quarts of CO2 building up in a 6-person cabin? Somehow that doesnt seem safe. There is air that is rammed into the cabin if the vents are open so I guess the CO2 might push out at a rate high enough not to build. But I dont know and being wrong means I'm dead.

Plus the unit instructions say in big bold letters "DO NOT USE DRY ICE" so, I dunno if thats a safety warning or a damage-to-the-unit warning

>>1058147
What? How does 150 degree aluminum cause wings to fall off?

>>1058141
>Every usual metal but copper
the heat exchanger (at least the fins anyway... I'll have to look more closely next time I'm there) is copper

> -26°C
oi thats cold. Damn I wish there was a way to do that that didnt cost $1500 for one of those deep chill freezers. But actually, that might just freeze the water that the pump uses? This thing needs a small amount of water that it pumps up to the heat exchanger... but maybe not if there was enough liquid water to start.

>Is a piece of pipe exhausting nitrogen/CO2 out of the plane really out of question?
eh.... we have a port hole in the back that we have cameras/senors attach to and see through, but having the covers off exposes the actual flight control lines which... that sketches me out. Plus if any faa inspector saw some tube dangling out or something that would definitely raise eyebrows. But then again I could probably figure out something.

Question still is though, how to keep something flowing through the pump withing it freezing up from being in contact with something crazy cold like liquid nitrogen? would antifreeze even work?

>>1058150
the heat thing only heats up to 150º? Are we talking Freedom degrees or that other kind with a c

>>1058147
CO2 becomes dangerous if the concentration goes above 30000-40000ppm/~5%, it doesn't take much. A kg of dry ice is about 500litres of gaseous CO2, so its easy to reach dangerous concentrations in a concealed small room. The small planes i've been in weren't exactly airtight but i wouldnt take the risk without equipment to monitor the concentration.

There is another problem: If you drop dry ice into your box the water will simply freeze, making the whole thing basically useless. You'd need to use a liquid with a thaw point below -76°C.

>>1058154
>the heat thing only heats up to 150º?
"At temperatures continuously above 100°C, strength is affected to the extent that the weakening must be taken into account."

if its only 150F.... that doesnt seem very efficient for taking heat away. the pics i looked up for those things showed them turning frosty pretty fast. thats gotta be more than a 60ºF swing.

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>>1058156
fugg man well that'd be why they insist you not use it

and we're talking about filling a 52 quart ice box lol, not just 1 kg. shit i'd be dead as fuck in no time.

>>1058156
also, doesnt the rate at which it sublimates depends on the ambient pressure? what happens when you climb to 10k'? it probably boils off way faster. accelerated death.

>>1058154
my idea was to use 60% acetic acid instead of water in the box. That would have a thaw point of -26°C and a higher thermal capacity than pure water, which should significantly increase the runtime of your air conditioning thingy. You don't need to get it to -26°C, but it would be an advantage to get it below that so that it partially freezes, further increasing its thermal capacity.

Getting the liquid to that temperature before you pour it into your air conditioner is easy, you just need a styrofoam box, some dry ice (a few $ each, dry ice is really cheap) and place the container with your liquid in box with it until it reaches the wanted temperature.

>would antifreeze even work?
No. You'd have to use a closed cycle running through radiator and the box with liquid nitrogen using something like halon 1211. But the whole pump setup wouldn't really be needed since it's so freaking cold. You could probably just pour it into a small, insulated container with a small radiator (like a CPU cooler) fixed to its bottom.

It's probably really impractical to build something like this, especially since the radiator would be way below 0°C so you'd have a shit load of ice building up on it. If you don't intend to put a lot of work into it and have fun to make something like that work best forget about it, it just came to my mind.

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>>1058167
yes, didn't even think about that...

>>1058167
>>1058175
and the lower the ambient pressure gets the lower will the temperature of the remaining dry ice get, further increasing the problems of finding a decent working fluid to make your radiator/pump setup work.

use block ice not chip

>>1057895
>What is galvanic corrosion
>what are sacrificial anodes

You're out of your depth mate, go back to sleep

>>1058097
Then the cabin fills with CO2 as the blocks sublimate...

Cooling air to cool aircrew is silly.

http://store.coolvest.com/

I've worn these T-shirts in very hot weather and they are far more comfortable than conventional cotton tees.

https://store.potomacfieldgear.com/store/comersus_viewItem.asp?idProduct=174

Wicking works. You should wear comfortable pants too. Hot weather BDU pants are the most comfortable pants I've ever worn.

The high dollar option:
http://www.livescience.com/47327-army-personal-cooling-systems.html

>>1058120
WTF no...

>>1057566

You can make water (mixtures) freeze at lower temperatures, but they won't absorb significantly more heat unless you go ridiculously low. Most of the energy goes into phase transition, the change in melting temperature is fucking around in the margins.

>>1057576

Salted water doesn't work. You "can't" freeze it in a normal freezer. Or rather it freezes mostly at 0 degrees, driving the salt out into a concentrated brine which won't freeze.

>>1058421

You can get those cooling vests with ice water reservoirs and pumps too, instead of packs you put into it.

>>1058414
no. the CO2 already subliminates as you are putting it into the alcohol. ethanol has a much lower freezing point than CO2. So when the dry ice cubes stop sublimating in the alcohol. You have -70 degree F alcohol.

>>1057566
Easy, just fill it with liquid nitrogen

how low do you fly or how much of a baby are you that you need air conditioning in a fucking airplane?

>>1058428
That's just bullshit. Go and try it now with a deep freeze, salt some water and cool it to -14. You'll realize you're talking out of your hole

>>1058363
Most people are not aware of electrolysis and sacrificial rods.
>firetrucks have zinc rods in the water storage tanks

>>1058478
way to not read any of the thread

>>1058458
send me some?

>>1059251
filling it with liquid nitrogen without modifications is a recipe for disaster/failure.

That said, it's really cheap, a few bucks per litre. Renting the dewar flasks it comes in is usually more expensive than the liquid nitrogen itself.