dehumidifying a whole hangar ???

[Alan Fox]

what are your thoughts , I just bought a plane that was sitting for 14 years in a hangar , and it is in remarkably good condition....the owner ran 2 dehumidifiers in the hangar......seems to be a fantastic idea ...

[bradp]

Was there a vapor barrier present in that hangar or just corrugated steel walls and a concrete floor?  

[AH-1 Cobra Pilot]

I would hate to pay for the electricity to constantly run two dehumidifiers!  Might be as much as your insurance.

I have an 800W dehumidifier = 6.6A.  If yours are larger, two may overload a 15A breaker.  Be sure to check.

[Marauder]

3 hours ago, Alan Fox said:

what are your thoughts , I just bought a plane that was sitting for 14 years in a hangar , and it is in remarkably good condition....the owner ran 2 dehumidifiers in the hangar......seems to be a fantastic idea ...

If I weren't paying the electric bill, I would consider it. The challenge with an uninsulated hangar are the leaks. It would be running constantly. You have been in my hangar, it is new but there are so many open seams that would let air in.

[milotron]

@alan fox

I have one of the small EVA-dry portable peltier dehumidifiers in the plane and they work great. I have a second, larger one in my garage and it ,mostly keeps up with the wet cars going in and out.  Very low power consumption as they don;t use standard refrigeration type dehumidification.  The small one in the plane is less than 20 watts I think, not sure of the large one.

 

https://www.eva-dry.com/

 

 

[carusoam]

Connect this with the thread using gun-safe dehumidifiers...

1) dehumidifying is a good idea.

2) the objective is to control the Rh below a certain point.

3) The challenge of a sealed box, is its total volume...

4) the challenge of controlling Rh, may include maintaining temperature some...

5) The challenge of a hangar, it’s not a sealed box, usually... and it’s volume is huge.

6) if you had a single dehumidifier and can aim its output towards the engine/cowling... you would want to recycle the air coming from cowling as well. This would minimize the energy used, not dehumidifying the world...

7) when dehumidifying the engine, it can be a challenge to get dry air into the oil sump, the air intake, and all the cylinders....

8) Consider building a cowling tent, dry air in, exhaust from the tent heads back to the dehumidifier's intake.

9) the tent contains the dry air.

10) Leave the oil fill cap open. Allow dry air to flow around the engine's air intake and exhaust, and case vent...

 

Use caution with really dry environments. They aren't very user friendly. Dry nose, mouth and eyes...

Dry environs also are good at allowing static build-up everywhere. Lots of sparks when you touch metal objects.

Be super cautious when working with fuel....

Ordinary PP thoughts only, not an hvac engineer...

Best regards,

-a-

 

[peevee]

I'd be curious to see a log of the humidity in the hangar with them running, it's a lot of volume and quite drafty so I'd imagine little benefit, but maybe not

[N201MKTurbo]

Move the hangar to Arizona. We don't have humidity here.

[Steve W]

Thanks for the Eva-Dry info, I just ordered one and a small pump to pump the water into a bucket outside the cockpit and another humidity sensor to put in the plane(I already have one for the hangar). I'll let y'all know how it goes. 

[Skates97]

On 1/29/2018 at 6:50 AM, Marauder said:

If I weren't paying the electric bill, I would consider it. The challenge with an uninsulated hangar are the leaks. It would be running constantly. You have been in my hangar, it is new but there are so many open seams that would let air in.

That would be my issue. I don't pay for electricity, it is part of the monthly rent. However, I might as well be trying to dehumidify all of southern California with as drafty as my hangar is. If the guy next to me closes his doors too much the wrong way I have a gap about 2" wide between his door and mine...

1 hour ago, N201MKTurbo said:

Move the hangar to Arizona. We don't have humidity here.

Except monsoon season...

[N201MKTurbo]

1 minute ago, Skates97 said:

That would be my issue. I don't pay for electricity, it is part of the monthly rent. However, I might as well be trying to dehumidify all of southern California with as drafty as my hangar is. If the guy next to me closes his doors too much the wrong way I have a gap about 2" wide between his door and mine...

Except monsoon season...

It's still less humid than New Jersey on a dry day!

[Mooneymite]

I've considered this for my hangar, but wonder if it's gilding the lily.

I suppose it depends on how pervasive high humidity is.

I keep a bunch of engine parts on shelves in my hangar here near Atlanta like mine canaries.  So far no reason to dehumidify.

I guess it's a cost/reward question?

[bradp]

Maybe a more modular answer would be to use an engine dehumidifier and a desiccant in the cabin ...

[jaylw314]

1 hour ago, Mooneymite said:

I keep a bunch of engine parts on shelves in my hangar here near Atlanta like mine canaries.  So far no reason to dehumidify.

I'm not sure why I find that image funny, but that made me laugh

[carusoam]

I had a lab that lost its relative humidity control over a weekend...

Ordinary metal parts on the shelf coated themselves in a rusty red layer.  Definitely works as a canary. 

Best regards,

-a-

[201Steve]

I’d like to resurrect this topic. I think about it often. As we know, humidity kills airplanes by way of corrosion. It’s the single most destructive condition. I’ve talked to the guy that sells the engine dehumidifier at Oshkosh, I asked him why nobody is tackling the whole thing? Not just the engine. What if it was practical to achieve low humidity for the entire airplane during disuse? Maybe it is. Hear me out. 
 

as is common, hangars are not airtight and often not fullly insulated. Difficult to humidify efficiently. Also, hangars are large. The hold a lot of air. What if we could: A) reduce the volume of air that needs treatment and b) solve the sealing problem? 
 

ok, how might we do that practically? A storage bubble. A storage tent. There are plastic bags that you drive your car into, inflate it with filtered air, and it eliminates dust for long term storage. Ok, an inflated bubble in your hangar. Option b) a tent. Ok, let’s say I built a frame out of light PVC. There is thick plastic sheeting walking the tent.   I rig a pulley system to the ceiling of the hangar. It has rubber on the bottom of the frame where it would seal against the floor. Raise and lower to store. Dehumidify that space. It’s sealed and contains no extra air to treat. 

 

 

[A64Pilot]

On 1/31/2018 at 1:33 PM, peevee said:

I'd be curious to see a log of the humidity in the hangar with them running, it's a lot of volume and quite drafty so I'd imagine little benefit, but maybe not

I have a 3,000 sq ft hangar in Central Fl, just south of Ocala, so it’s humid. It’s concrete block with folding doors and a finished ceiling that’s 12’ tall.

I dehumidify it, I can’t show you a log but I can show you run times per day of the 2 ton mini split that dehumidifies it during warmer times and I run one 60 qt per day dehumidifier plus the AC in colder months.

I have a humidistat that turns the AC on at 65% RH and off at 60% RH, the dehumidifier isn’t as precise it doesn’t turn off until about 55% but one click higher it turns off at 65% or so which is too high.

I use this thermostat for the mini split https://cielowigle.com/cielo-breez-plus/

I got 65% RH from internet research, I found a chart that showed that corrosion of 2024 and 6061 got steep at 65% RH, and of course I can’t realistically drive the hangar to below 50% or I would.

I think it costs about $50 a month to dehumidify the hangar on average, but it also keeps it say no hotter than mid to high 80’s in the middle of Summer and I can keep it at 60F when outside temps are 32 or so, so if I know I’m going to work in the hangar I can turn the heat or AC on the night before.

AC use is hugely variable, if it’s a rainy day all day the AC will run almost continuously, but it may go several days and not run at all.

Attached is sort of a typical week if there is such a thing, a good 2 ton mini-split is very energy efficient as they are variable speed compressors, the design is to vary speed as opposed to constantly turning on and off so long run times doesn’t necessarily mean it’s running full speed, but in my case it likely is.

 

[A64Pilot]

During colder times just a little heat will drive down RH substantially, remember RH isn’t a measure of how much water is in the air, it’s a measure of how much water is in the air relative to how much the air can hold, increasing temp raises airs ability to hold water. A dehumidifier both dehumidifies and adds a little heat

Peltier principle things are very, very inefficient, a Peltier plate is attractive because they can be very small and have no moving parts and are cheap, but you give up efficiency, they are I believe less than 10% efficient, where an efficient heat pump can be 300% to 400% efficient.

I think if you owned a hangar then you could seal it up very effectively with spray foam insulation. In my hangar my problem is door gaps, but unless the wind is blowing from the East there isn’t much leakage. I would love one of those big hydraulic doors, but they are as expensive as a new glass panel, and I would never save enough electricity to pay for that.

[slowflyin]

I'm located in VA.  For years I struggled with my Q-hut hanger.  Cold as heck in the winter and unbearable in the summer.  Worst of all was the corrosion on my tools.   When I bought my Bravo I decided something had to be done.   Three inches of spray foam insulation and a mini split turned my hangar into paradise.   It definitely controls the humidity and when I'm working on the plane I just rachet the thermostat down to 75.   The variable speed compressor in the mini split has eliminated any concerns about short cycling and ineffective humidity control.  It's a whole different experience!   Winters are the same.  I typically set it on 50.  If I'm flying the next day or working one the airplane, I turn it up!