My new DIY humidifier for large fridge.

[Duntov]

My goal was to have enough output for my converted commercial refrigerator with a self feeding water supply.  I decided to try an ultrasonic unit and learned quickly that the level of water above the ultrasonic wafer is critical.  I stumbled upon a high output unit with a float cradle that solved the problem.   It is working great.  I used a food container and modified with two aquarium bulkhead fittings.  A large one for output and a small one on the side to mount a micro water-proof fan.  Both the ultrasonic unit and the fan use 24V DC.  The automatic water feed and level is controlled by a float valve.  For the water feed bulkhead in the fridge, I used a hollow lamp stud found at my local hardware store.  The 1/4" feed line slid nicely through it with minimal gap.  I tapped into my existing RO water filter unit for the feed.  Water being supplied is super pure.

I am finishing up on adding a 110v to 24v DC step down transformer in my master controller box.  There is no external power supply or wires.  All will be internal and hidden.  I also use a small fan that runs constantly that keep the humidity and temp even throughout the cave.

[awakephd]

Definitely worthy of AC4U!

[Andrew Marshallsay]

A nice bit of innovation. Please accept another cheese from me.
This is something which I have struggled with and I am very impressed with your solutions.

[Duntov]

Thanks for the cheeses. 

Another tid bit of information on ultrasonic units.  The warmer the water in the tank, the more output.  I originally wanted the whole unit outside the cave altogether.  That would free up cave space and provide for warmer water in the tank.  But that introduces new challenges like air filtration, air leakage/cleanliness and a stronger flow. 

I found a 3/4" one way check valve used in aquarium plumbing that has a flapper door that seals quite nice and would not allow cold air to escape when the humidifier turns off.  But it requires some psi to open properly.  One solution is a high pressure blower fan but they are very loud like a vacuum cleaner.  The valve needs about 30-40 psi to work properly.  After reading up on the humidifiers used in large commercial caves I learned they use compressed air in most of their units.  I have an air source already and with a simple 110v solenoid valve it should work.  Of course a separate regulator and filter would be required.  I will be experimenting with this.

[Duntov]

I tried the external approach but it is a no-go.  Two problems persisted.  Even thou I used low pressure, the compressor came on too often and it was quite noisy.  The second problem is that when the 'warm' fog hit the cool air, it instantly condensed.  I will stick to my internal system as it is working perfectly and doesn't require filtered air.  I am resigned to using a up a bit of cave space.

[Col68]

Very great professional work, I can only say Bravo and thank you for sharing, good continuation.

[Duntov]

Update:  This is the best mod I have made so far.  The humidity never varies and because I don't need to open the cave to replenish the water, everything is very stable.  The added benefit is that I can go on a long vacation without worries.

[John@PC]

Did you get your mist maker from The House of Hydro?  Asking because I know they're close by in Ft. Myers.  How do you control the humidity: humidistat or timer?  By the way a cheese for the successful project .

[Duntov]

Did you get your mist maker from The House of Hydro?  Asking because I know they're close by in Ft. Myers.  How do you control the humidity: humidistat or timer?  By the way a cheese for the successful project .

Yes, I got the mist maker from House of Hydro with the tuff coating.  I control it with a Whilhi 7016 series controller.  Thanks for the cheese!

[John@PC]

WH1716 is for temperature so I assume you are using that for your fridge.  Do you use the Willhi 8040 or another brand of humidistat for the RH?

[Duntov]

WH1716 is for temperature so I assume you are using that for your fridge.  Do you use the Willhi 8040 or another brand of humidistat for the RH?

Oops, my mistake.  The humidity controller is the WH8040 and the temperature controller is the WH7016D.  Thanks for the catch.