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Posted

I thought i had posted this before but can not seem to find the thread so sorry in advance if you have already seen this but this is my setup for dehumidifying my engine. Its a 4000 sqft room dehumidifier off of amazon and some ventilation piping from home  depot that i used to direct the air down to 3 inch pipe to fit over the oil fill tube. The other end fits into the packing foam plate that came with the humidifier to protect it during shipping and works great when you cut a hole in it matching the exhaust vent of the dehumidifier and a humidifier power switch for closed loop operation to keep the humidity in my desired level without keeping the dehumidifier running constantly.

Vacplus 60 Pints 4,000 Sq. Ft.... https://www.amazon.com/dp/B08ZXTZFXL?ref=ppx_pop_mob_ap_share

WILLHI 1803-H Humidistat Digital... https://www.amazon.com/dp/B07VNFM94W?ref=ppx_pop_mob_ap_share

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Posted
7 hours ago, Will.iam said:

humidifier power switch for closed loop operation to keep the humidity in my desired level without keeping the dehumidifier running constantly.

How far down into the oil filler does the humidistat detector go?  The pic seems to show you just lowering it into the oil filler tube.  Also, is there any form of "gasket" or filler to make the output from the dehumidifier fit the oil filler tightly?

Posted

Most dehumidifiers put out a large volume of air at a pretty good velocity.  I'd say even if it's not sealed up dry air is forced down the filler tube increasing the crankcase pressure.  A tight seal probably wouldn't move more air as the crankcase vent is relatively small.  The rest of the dry air will fill the cowling.  Seems like dry air on the exterior and all the assorted accessories would be a good thing.  

Posted

I built one that pumps dried air into the crankcase breather tube.  I cover the ice holes in the breather tube with tape and loosen the dipstick and cover it with a rag.  That's an easier connection.

 

Posted
2 minutes ago, 0TreeLemur said:

I built one that pumps dried air into the crankcase breather tube.  I cover the ice holes in the breather tube with tape and loosen the dipstick and cover it with a rag.  That's an easier connection.

 

What moves the air?  Same idea as Will.iam?  Does it run continuously, or do you also have a humidistat to control the dehumidifier?

Posted
5 minutes ago, Fly Boomer said:

What moves the air?  Same idea as Will.iam?  Does it run continuously, or do you also have a humidistat to control the dehumidifier?

We don't need a high air flow rate, so I used a piezoelectric aquarium air pump that lives in a chamber together with a heat sink on the cold side of a Peltier cooler.  The pump runs continuously.  A controller reads a thermocouple on the heat sink and cycles power to the Peltier, to keep the heatsink nice and cold, but not iced up.  From that chamber, the air is pumped into a second chamber containing a temperature/relative humidity sensor.  I use a research grade sensor not one of those cheap ones that comes with most projects.   If the dew point of the air flowing towards the engine ever exceeds 15C, the controller shuts the system off and sets off a warning light.  Works great.

  • Like 1
Posted
1 hour ago, Pinecone said:

Have you checked to see if you are getting significant airflow out of the breather? 

I am wondering how much is going through the engine.

This thing blows a lot of air. At first i tried to restrict all the air to go though the engine. While this does work the air was getting heated up by the fan blower motor and i questioned the longevity that would result from overworking the fan blower instead just putting it over the top loosely and having air blow around the oil filter to as well as down through the oil filler tube I’m getting dehumidified air throughout the cowling, and I put my hand down where the breather tube is and you can feel hot, moist air coming out and you can even see the steam coming out of the breather tube when you first put it on the oil filter tube. 

Posted

Thanks, that is what I wanted to know.  Air has a tendency to take the path of least resistance, and wanted to make sure that enough was going where you wanted it to do.

Another option, would be to make it tight fitting, but with a bleeder hole.  That way you could control the pressure to ensure that a good bit of air went into the engine.  But it is a good thing to flood the cowl with dry air also.

Posted
1 hour ago, Pinecone said:

Thanks, that is what I wanted to know.  Air has a tendency to take the path of least resistance, and wanted to make sure that enough was going where you wanted it to do.

Another option, would be to make it tight fitting, but with a bleeder hole.  That way you could control the pressure to ensure that a good bit of air went into the engine.  But it is a good thing to flood the cowl with dry air also.

This dehumidifier is designed to dehumidify a 4000sf room. While i do not have a 4000sf room we did have a bathroom that had an overflow toilet and once we got most of the water up with a shop vac, i went and got this dehumidifier off my plane and stuck it in the bathroom. It was amazing hiw much water it sucked out of the room and within 24 hours everything was bone dry. Now that was a 150 sq ft room. That engine compartment is only 5sq ft at best with the internal part of the engine much smaller so i have no doubt this is way overkill for what I’m using it for. In fact if my hanger was better sealed up i would say it could lower the whole hanger but unfortunately it’s not. 

Posted (edited)
21 minutes ago, DonMuncy said:

Any idea how that dehumidifier works? What the mechanism is for removing moisture?

AFAIK, there are two methods:

  • True dehumidifiers, works like AC, they cool the enough to freeze the water content on it, the air then has true less absolute humidity, and usually is cooler.
  • "Fake" ones, they just heat the air, lowering the relative humidity but keeping the absolute humidity the same.

I don't know if there are any version using silica gel or similar stuff.

Edited by redbaron1982
Posted

It would seem that an AC type dehumidifier would be awfully expensive (relatively speaking). 

The one I built uses silica pellets. Naturally, it entails the periodic re-drying of the silica.

Posted
It would seem that an AC type dehumidifier would be awfully expensive (relatively speaking). 
The one I built uses silica pellets. Naturally, it entails the periodic re-drying of the silica.

How long would silica pellets work in a humid environment (Houston, Florida for example)?
Posted

They exist, and can get get some stupid low humidity.  As in, an entire building where the humidity is so low, when you enter, your eyeballs feel prickly from the moisture being evaporated off them. :D  Down in the range of 0.03% RH.

They work like a heat recovery wheel.  Think a roll of corrugated cardboard with the cells running parallel to the axle.  The cardboard is impregnated with some salt, say Lithium Chloride (one possibility).  Through about half the rotation, room air is blown through it.  The moisture is absorbed out of the air.  The other half of the rotation, hot air is blown through the roll to remove the moisture and that air is directed outside the space.

I have been involved in projects that used small ones about the size of room dehumidifier, up to ones up to sizes that only one would fit on a flat-bed trailer.  I had one project where, due to a broken fire sprinkler line, we pumped an Olympic size swimming pool of water into the 6th floor of a 7 story building.  With a battery of these type units and a lot of work, we were able to get the building dried out without getting mold growth.

 

  • Like 1
Posted
2 minutes ago, Pinecone said:

They exist, and can get get some stupid low humidity.  As in, an entire building where the humidity is so low, when you enter, your eyeballs feel prickly from the moisture being evaporated off them. :D  Down in the range of 0.03% RH.

They work like a heat recovery wheel.  Think a roll of corrugated cardboard with the cells running parallel to the axle.  The cardboard is impregnated with some salt, say Lithium Chloride (one possibility).  Through about half the rotation, room air is blown through it.  The moisture is absorbed out of the air.  The other half of the rotation, hot air is blown through the roll to remove the moisture and that air is directed outside the space.

I have been involved in projects that used small ones about the size of room dehumidifier, up to ones up to sizes that only one would fit on a flat-bed trailer.  I had one project where, due to a broken fire sprinkler line, we pumped an Olympic size swimming pool of water into the 6th floor of a 7 story building.  With a battery of these type units and a lot of work, we were able to get the building dried out without getting mold growth.

 

I was thinking exactly on that, a wheel that is constantly exchanging the dehumidifying material between room air and hot air vented outside. 

Shouldn't be something expensive to make (not sure how much to buy)

 

Posted
1 hour ago, DonMuncy said:

It would seem that an AC type dehumidifier would be awfully expensive (relatively speaking). 

The one I built uses silica pellets. Naturally, it entails the periodic re-drying of the silica.

Silica gel is not the greatest for drying, it gets less effective as the temperature rises, so with temp changes in the hanger, it can 'breathe' water in and out.  That's fine in a closed system, though, so stuffing a sock full of dry silica gel and tossing it in the cabin works great.

Zeolite or calcium oxide are probably better dessicants, since they hang on to water even as the temp increases to non-oven type temperatures.

Posted
4 hours ago, DonMuncy said:

It would seem that an AC type dehumidifier would be awfully expensive (relatively speaking). 

The one I built uses silica pellets. Naturally, it entails the periodic re-drying of the silica.

Can’t find any specs but comparable dehumidifiers draw 900-1,000 watts/ hr.  In humid regions with naturally leaky hangars it will run a lot. Purchase price and operating cost aside, many publicly owned hangars will not allow operation unattended. 

Posted

I just dehumidify the entire hangar, with believe it or not but a 50 pint dehumidifier, during cold wx like now and a 2 ton mini split during warm months.

It raining and 100% RH now outside and inside the hangar which is 3,000 sq ft it’s 62%, the Mini split Humidistat is wifi connected and keeps track of humidity even when the AC is off, but keeping the hangar always dry should really help with the whole airplane corrosion to include all my tools etc.

Cost wise I think is about $50 a month on average, about he same as the pool. some months they hardly run and sometimes in weather like now they hardly shut off, I have them set to turn on at 65% and off at 60%, I found a chart online that showed corrosion of 6061 and 2024 at different RH, at 65% the curve got steep.

The AC of course cools in warm wx and the dehumidifier adds a little heat in cold, but keeping the humidity down really makes it more comfortable in either warm or cold.

 

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Posted
12 hours ago, DonMuncy said:

It would seem that an AC type dehumidifier would be awfully expensive (relatively speaking). 

The one I built uses silica pellets. Naturally, it entails the periodic re-drying of the silica.

Mine is an ac unit that chills down the air which gets the moisture out then blows that air into the room or tube in my case that pushes it through the engine. It’s about half the price of the black max engine saver and was one of the reasons i went searching for a non aero model so I didn’t have to pay the aero price. I never have to worry about silica that gets saturated. I did have to run a hose from the drain to outside the hanger as the catch bucket is only about 2 gallons and will fill that depending on the relative humidity rather quickly which has an autoshut off when it gets full. Since it’s clean water from condensation i use it to fill my golf cart batteries when they get low or anytime i need water without contaminates. As a side note after i started using my humidifier my last oil sample blackstone made commit that i had unusually low water content in the oil sample and i have noticed my iron content is lower than last sample before i used the dehumidifier so there is that effect as well. 

Posted
7 hours ago, A64Pilot said:

I just dehumidify the entire hangar, with believe it or not but a 50 pint dehumidifier, during cold wx like now and a 2 ton mini split during warm months.

It raining and 100% RH now outside and inside the hangar which is 3,000 sq ft it’s 62%, the Mini split Humidistat is wifi connected and keeps track of humidity even when the AC is off, but keeping the hangar always dry should really help with the whole airplane corrosion to include all my tools etc.

Cost wise I think is about $50 a month on average, about he same as the pool. some months they hardly run and sometimes in weather like now they hardly shut off, I have them set to turn on at 65% and off at 60%, I found a chart online that showed corrosion of 6061 and 2024 at different RH, at 65% the curve got steep.

The AC of course cools in warm wx and the dehumidifier adds a little heat in cold, but keeping the humidity down really makes it more comfortable in either warm or cold.

 

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Wish my hanger was better sealed but don’t have the money for that right now. There are days where the outside humidity is less that my set level and the dehumidifier never comes on, by the rainy days it almost never shuts off for long. With the blower motor working hard to force the air down the tube i find in the winter months my engine will be anywhere from 5 to 15 degrees warmer than the outside temp when the humidity has been high and the dehumidifier was running a lot through the night so gives me a head start on warming up the engine for start on those cold mornings. 

Posted
19 minutes ago, Will.iam said:

Mine is an ac unit that chills down the air which gets the moisture out then blows that air into the room or tube in my case that pushes it through the engine. It’s about half the price of the black max engine saver

My understanding is that a Black Max sells for about $600; meaning yours was about $300. That is a very good price for an engine dehumidifier. Mine was not that expensive, but you didn't have to buy parts and assemble yours; and you don't have to cook the pellets every 4 months or so, like I do. Thanks for the information.

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