Hot Humidor - why?

[Philc2001]

The temperature inside my humidor is about 5-6 degrees F warmer than the temperature outside the humidor. I have about 25 boxes in there at the moment, it's pretty full. Over the weekend I installed a new fan in the humidor, the old one died a few weeks ago. The new fan is a 120mm x 120mm x 25mm, 51CFM, I got it from Amazon:   https://www.amazon.com/gp/product/B009OWVUJ0/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

The fan itself does not feel hot, so I don't think it is the source of the heat. The cigar boxes inside feel warmer than ambient air, and it seems the warmth is consistent around the humidor. The current RH in the humidor is 61-62rh. I'm using two different hygrometers. When I put the two hygrometers right next to each other, either inside or outside the humidor, the temperature is less than half a degree difference between them, and the RH is almost always the same between both of them. But when one is outside the humidor, and one inside, the inside one reads 5-6 degrees warmer. I alternated the two hygrometers between inside and one outside the humidor, but the results were the same.

For now I've decided to turn the fan off just to see if that makes a difference. I'll give it 24 hours to see if that changes. Anyone have and idea what might be causing the heat?

[Fuzz]

Where is the humidor in your house? Near any heat sources?

 

[PapaDisco]

Is the interior lit?  If so has the contact switch failed in the "on" position?

this does sound weird  

[Philc2001]

The humidor is located in the corner of a room under the AC vent. There is no heat source nearby.

 

The humidor is a wineador, Haier brand 32 bottle wine cooler, but it’s not plugged in. I have not run it for years. There is an interior light, but it’s not lit since the cooler is not plugged in.

 

I am very suspicious of the fan I put in on the weekend. It doesn’t feel hot but it may be generating heat. I’ll give it some more time, but since I turned the fan off 8 hours ago it appears the temp is coming down some.

 

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[LLC]

Based in all you've said and the fan being the one variable that changed, my guess is it has to be the fan.


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[BrightonCorgi]

Is the fan on a timer?  If not I would install an external one.  You don't need the fan running all the time.

[Fuzz]

Easy test. Turn off the fan and see if there is a temp difference. Turn it back on and see if it changes again.

[Philc2001]

So, after 12 hrs with fan off it looks like it has nearly equalized, so the suspicion of the fan causing the problem is confirmed. What is odd about it is why would a cooling fan generate so much heat? I can't imagine the friction of air movement being the issue because I had a fan in there before, that moved more air than this one, so something is weird about this fan. To the touch it does not feel hot, so where is the heat coming from?

I'll have to look into getting a timer, but has anyone observed their fans causing this much heat?

[JR Kipling]

Electric motors produce heat as a byproduct. Somehow that heat is getting transferred to your humidor apparently.


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[BuzzArd]

I will say, when I installed a 115v fan in the icebox humidor the temp shot up about 6-8°.

I reworked it for a 12v fan and had much less heat production. 

Have an IR thermometer handy?   Shoot the fan and see.  Mine was about 110° running inside a 10cubic foot cabinet.  Easy to see the temp rise reason. 

[Fugu]

  On 11/1/2017 at 1:41 PM, Philc2001 said:

To the touch it does not feel hot, so where is the heat coming from?

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Replace the fan. The fan won't feel "hot" because it dissipates generated heat quickly (function of a fan....). But it feeds your insulated environment continuously with heat. Even a small, continuous input will lead the storage temp to rise. And it does so very effectively as it seems, from what you describe (so, I'd still expect it to feel slightly warm to the touch). If that's the only thing you changed between before and after the temperature rise, it can only be the fan.

It seems you fetched a crappy, inefficient fan. While you took the fan out, you can make a simple test and let it run in a smaller confinement (e.g. a thicker cardbord box of 20-30 l) with a wired thermometer probe included. Take regular readings....

[Philc2001]

  On 11/1/2017 at 3:37 PM, BuzzArd said:

I will say, when I installed a 115v fan in the icebox humidor the temp shot up about 6-8°.

I reworked it for a 12v fan and had much less heat production. 

Have an IR thermometer handy?   Shoot the fan and see.  Mine was about 110° running inside a 10cubic foot cabinet.  Easy to see the temp rise reason. 

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yes, I was trying to avoid using a transformer, but it looks like a 12v fan may generate less heat. I wonder if a USB powered fan would work. 

[BuzzArd]

  On 11/1/2017 at 3:45 PM, Philc2001 said:

yes, I was trying to avoid using a transformer, but it looks like a 12v fan may generate less heat. I wonder if a USB powered fan would work. 

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Running temp of the 12v fan I chose is around 85°.   I have a timer to run it on, but have yet to hook it up.  I specifically looked for a cool running fan. Look at that old thread and see what I ended up putting in. I'm pretty sure I said what it was. I think it had liquid cooled bearings in it.   And it was still cheap. 

[BuzzArd]

Here's the fan.  Super quiet.  Fluid dynamic bearing which is supposed to be good for fans mounted in any orientation, and mine went in horizontal.  Plenty of CFM for a small cab. This one in this size is sold out, but find the size you need and give it a try. 

https://www.amazon.com/gp/aw/d/B0032UV45K/ref=yo_ii_img?ie=UTF8&psc=1

[Romka]

Your cooler has a good thermal insulation. Whatever fan you install inside, inner temperature will always be higher than the ambient temp inside the room. Fan efficiency is important but I dont think you will have much difference out of fan technology or switching voltage unless your first fan is crap. Try to lower CFM, and check if you really need that much of air movement within a confined cooler space.

[vladdraq]

maybe your cigars are going through a third fermentation. Or a second sick period. or both!

 

[Philc2001]

  On 11/1/2017 at 8:30 PM, Romka said:

Your cooler has a good thermal insulation. Whatever fan you install inside, inner temperature will always be higher than the ambient temp inside the room. Fan efficiency is important but I dont think you will have much difference out of fan technology or switching voltage unless your first fan is crap. Try to lower CFM, and check if you really need that much of air movement within a confined cooler space.

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Previous fan died so I opted for a replacement. However, I only ran the previous fan periodically on a manual switch, and I had a speed control on it. But I seldom observed a variance of more than 2 degrees. The replacement fan is bigger (120mm vs 80mm) but it only moves 51CFM (a so-called low-speed fan). I'm looking for a timer control. I'd like to run it for 5 minute duration at 30 minute intervals or so.  

[BuzzArd]

  On 11/1/2017 at 10:24 PM, Philc2001 said:

Previous fan died so I opted for a replacement. However, I only ran the previous fan periodically on a manual switch, and I had a speed control on it. But I seldom observed a variance of more than 2 degrees. The replacement fan is bigger (120mm vs 80mm) but it only moves 51CFM (a so-called low-speed fan). I'm looking for a timer control. I'd like to run it for 5 minute duration at 30 minute intervals or so.  

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I got this timer.  I'll set it up to run 5 minute/hour when I get to it.   I'm sure they make a 120v version too 

https://www.amazon.com/gp/aw/d/B00PD65UGA/ref=yo_ii_img?ie=UTF8&psc=1

[oakalley]

Has to be the fan. That seems to be the only variable. I believe a good test was mentioned above, plug it in inside a closed space and let it run for a few minutes and check it with an infrared thermometer. I bet you will find the little hummer is producing more heat than you would expect.


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[Philc2001]

I was thinking of adding something like this:

https://www.amazon.com/dp/B01G6O28NA/ref=nav_timeline_asin?_encoding=UTF8&psc=1

It seems I can program the on and off duration in a repeat cycle, and it has a built-in battery backup. Not sure how often to run it, I'm thinking on for 1 minute, off for 10 to 15 minutes. That would provide 4-6 minutes of run time per hour, so I would think the heat generated would be minimal. 

 

[OB1]

Any motor will generate heat as they are all less than 100% efficient. I run my fan a few minutes per hour. 

[PigFish]

... that is a big fan! Is there any speed control on or attached to the fan that is interior of the humidor?

All appliances will create heat (somewhere). It is a byproduct of using energy to run...

If you choose a timer, make the frequency often and duration small. When I set my small programable timer units, I program them to run about 30% duty cycle, 150 seconds on and 450 off.

I see you like computers. If you have an old computer power supply around (switching 12VDC) you can certainly use that. Just ID the 12VDC side (yellow or red probably) and you can certainly use that to start. I use a dedicated industrial automation 12VDC switching power supply.

Best of luck! -P

[Romka]

I would use less frequent start/stops as the starting current of motors we are talking about is nearly 6 times of the nominal current. If you start/stop less frequently and run for longer periods, less heat will build up. This is from electrical engineering side, a climatologist/mechanical engineer or experience will tell the circulation rate needed.

[Romka]

A computer fan is a good idea. You can look at amazon for computer fans, check reviews and pick one. A computer power supply or any 12Vdc SMPS will do the job as Pigfish suggested. Try to minimise 12Vdc cable length but dont put the power supply inside cooler since it is another source of heat.

Many years ago we had a project in Chaikovsky/Ijevsk Russia. There were no means of communication so we had to buy a satmarine antenna. Damn thing did not work consistently whatever we a ton of hardware and software engineers did. Finally one bright technician proposed to install an incandescent bulb inside the antenna sphere to keep it warm and it worked flawless. Yes, it was like -25C to -40C outside and again yes, it was the birthplace of Chaikovsky.