EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: johnlsenchak on September 14, 2018, 01:14:31 am
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Incredible solid state dehumidifier. No moving parts.
bigclivedotcom
Published on Sep 13, 2018
This is a very intriguing device that uses a low current at low voltage to transfer moisture from inside an enclosure to the outside. Effectively a solid state dehumidifier with no moving parts. The version I put in the box is a PD2 and is rated to remove up to 84mg of water a day, so really intended for small enclosures.
The large square unit can handle up to 2.9g of water a day.
https://www.youtube.com/watch?v=Vabq-s62IVM&feature=em-uploademail (https://www.youtube.com/watch?v=Vabq-s62IVM&feature=em-uploademail)
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A Peltier device. Nothing new here. When you apply DC power to them they get cool on one side and hot on the other. They burn lots of power and are very inefficient compared to regular refrigeration coolers. You're never going to achive that level of performance except under perfect conditions with large heat sinks on both sides and with a good cooling air flow and with humid air that is close to it's dew point. I've been playing with these since about 1970, we used to call them Frigisters.
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A Peltier device.
That's actually some sort of ion exchange membrane, completely different principle. The one shown in operation uses a few tens of milliwatts.
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For a second I thought it was this bigclivedotcom video --- to which the title could just as well apply:
https://www.youtube.com/watch?v=AQtrXXySHc4 (https://www.youtube.com/watch?v=AQtrXXySHc4)
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Clive mentioned that the sensor *might* be dissociating the water, pushing only the Hydrogen through the membrane leaving the Oxygen on the inside of the housing.
I wonder if this was the case could the device just not be left inside an enclosure, which after time would be devoid of water but full of a O2 / H2 mixture? - if indeed it works that way perhaps it's a good reason to vent the H2 externally. Interesting.
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the youtube comments answer the question about gasses
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the youtube comments answer the question about gasses
This one:
@ShyToad 1 dag geleden (bewerkt)
The oxygen actually goes out with the hydrogen. The water molecule is disassociated in the membrane and reassembles on the other side as water. Here is from the company documentation. "Through a process of electrolysis the water passing through the membrane dissociates (breaks down) into hydrogen ions and oxygen which continue to pass through to the other side of the membrane where they recombine and are discharged into the air as water vapour. "
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if you read into them further someone gives you a percentage that it increases by, some kind of gradient forms eventually, but its under the LEL like <5%
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That's pretty cool, after looking at this I ended up reading about Oxygen concentrators using Zeolite, it's not electronics but interesting anyway.
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A Peltier device. Nothing new here. When you apply DC power to them they get cool on one side and hot on the other. They burn lots of power and are very inefficient compared to regular refrigeration coolers. You're never going to achive that level of performance except under perfect conditions with large heat sinks on both sides and with a good cooling air flow and with humid air that is close to it's dew point. I've been playing with these since about 1970, we used to call them Frigisters.
A couple weeks ago I was talking about my audiophile (only a small percentage were phools at the time, audio was hard to achieve then with vinyl, tape, tubes) old times.
One of my audio circle of friends was the national sales manager for John Carver (flame linear, pioneer, Acoustic Research etc). He had asked me about heat problems to solve in new amplifiers, and I mentioned the new device I had just read about in EDN or other trade rag.
When on the phone with John Carver he mentioned my idea of using this new Frigistor to actively suck the heat from the new FET or whatever final semiconductors. Carver dropped the phone, said my friend. true story.
BTW lots of this audio stuff happened around the Lawrence-Andover
Massachusetts area then.
Have you read the news today? One of the many homes blown up by natural gas in the towns was across the street from him, fortunately he has oil heat, but was evacuated anyway.
A chimney section landed on the car where the 18 yr old that was killed next to his friends.
My friend, bit shaken up, but are staying in their kids home till power is restored. His wife was not home fortunately. Now he's worried about damage to his foundation, etc.
Back on subject, to this day no one I've known ever heard of a frigistor.
I knew it was a Peltier device at the time, but never heard in the mainstream frigistor again till now.
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if you read into them further someone gives you a percentage that it increases by, some kind of gradient forms eventually, but its under the LEL like <5%
Add oxygen ion pump like the ones in wideband lambda sensors ;D