I used to use them way back in the late 90s, around the AMD K6 or Pentium III era. They worked very well unless the fan on your heat sink died, then they were capable of some extreme temps on the hot side and would typically burn out.

It's really inefficient compared to the refrigeration and newer desiccant drum style dehumidifiers. More of a novelty than a useful device unless you have a small space needing kept dry with just a 12V supply. (Like a remote cabin with a solar panel.)

sWeasel511 no clue about what?

That's a rather ironic comment given that you spelled 2 out of the 4 words incorrectly.

lern how too spoke enlish!

RCLifeOn or fridge. This is what those tiny mini fridges use, and why they can often warm cans up as well (by reversing polarity across the PD).

Instablaster.

+Patty Two Wheels A recent test showed that the peltier unit was only about 20% as efficient as the desiccant drum unit. So the initial cost of the small unit would soon be outweighed by the running costs.

+bigclivedotcom and the full switch will never work and less one it changers its mind to how much water it wants to get out of the air

The point of the vid is this design is bad even when optimized it’s just a very ineffective way if you’re looking to actually draw a decent amount of water per day. This inherent limitation and slope of increasing inefficiency as the area around it comes to temp. His whole point is this would be completely ineffective in any practical sense. So I don’t suggest you waste your parts and time this way, Peltier modules as a whole are just super inefficient even with the high power units it would be terrible at this practically for condensation uses even with high power consumption. The math has been done and even with the most efficient end best units we can make it would still be wildly ineffective. Technically they work but there exist much better ways as even refrigeration with gasses abs compression is more efficient generally. Hence the self filling water bottle thing or the “water seer” devices and anything similar can never work and would barely provide a few sips of water a day. Sorry but they haven’t found a miracle that solves the water crisis so simply and easily. Keep in mind the Waterseer was a straight up scam and basically so is any similar fonts self filling bottle and they absolutely know it never word. And high school student could do the math to show what would be produced with the power used and the modules we can make and quickly find the idea as laughable and only works technically ever so slightly in (theory usually lol) as being a step away from free energy . Physics says so. Maybe try some of the other project uses for your spare unit and make something more useful and effective like a fridge. And you could do solar but the required panel would defeat the purpose and raise size and cost vastly. Wall power is cheap and likely available to you.

Of course it adds about 30W of heat to the space it's operating in, which lowers the humidity by raising the temperature. When I worked with my dad in a resort, there was a 100W light bulb in the outdoor box that contained the PA system, just to keep it a little warmer inside and prevent condensation that would mess up the electronics. So in a confined space like a linen closet, this peltier unit might be as effective as a 40W bulb.

What the hell are you on about

This is a dehumidifier ...

Duh...

hey I got one of these and want to use it in my fridge i dont want a dessicant dehumidifier as it adds more heat what can i do to make it stop freezing up. I have a controller i can use to control the on/off and humidity %

@@ugursenturk5860 this will also generate heat. In order to make a cool side to collect condensation, the peltier must also have a hot side.

The peltier fridges are terrible. very inefficient, but cheap to make and sell to people without actually mentioning that the running costs will be so massive.

They're really meant to be used for small, battery powered chillers. Or in small places like a gun vault or safe. Something to bring camping or on a picnic to keep things cold for a few hours. If you don't need it to be portable, phase change is absolutely the best option.

If it's for filament storage, I use a large storage box with foam tape round the lid as a seal and a silica gel desiccant block with integrated heater for drying itself out when needed.

@@bigclivedotcom Thanks for the reply, any chance of a video of your setup, or have I missed it?

Alexander Thomas I've used a 'proper' dehumidifier to dry our washing indoors, and the amount of water it removed from the environment, even with no washing behind dried is impressive. Easily enough for two people to drink in case of emergencies wth a generator.

I take it you must have run an external power supply to it? One of the applications where this thing would really work well is in a remote caravan with its own solar panel so that when there was enough sunshine the unit would trundle up and start extracting moisture from the interior and draining it to outside.

A bit late But, When you get close to the end of your journey turn off the heating in your car, open a window and let all the heat out of your car so the windows, seats etc, are the same temp as out side so condensation cannot build up with the heat difference, also when it's snowing out side try not to get snow inside your car of your shoes, get some rubber collector mats for your car, the type that have a grid cell pattern on them to collect the water off your shoes then you can just tip the collected water out of the car. always worked for me and still do it to this day.

+Alter Kater probably built one

***** some dehumidifiers are a waste of money

You are correct, if you change the heat sinks with larger sized ones in the cold side then you can eliminate that issue. Considering people would likely be hacking these devices for other purposes if they're changing polarity anyways, it's a simple matter to do. The peltier element itself works just as efficiently in either polarity, it's only the heatsinks that make a difference.

These things can never be efficient, even in their absolute optimum operating conditions.

It pulls the air in across the cold side before passing it over the hot side.

I'm not sure. One option might be to turn the fan off and reverse the polarity briefly to warm the condensing surface.

@@bigclivedotcom Yup tought about that also but tried to simplify to the max. Thank you very much for your quick reply and greetings from Buenos Aires, Argentina.

These Peltier modules do not like being switched on and off. I fitted a humidistat with a relay to turn it on and off. It stopped working after a few weeks and I had to fit a new Peltier.

I noticed that this unit seemed to have an excess of heat sink compound.

I tend to recommend using a real dehumidifier like the eco air simple which uses a rotating desiccant drum. They are much more efficient at pulling out a lot of water.

+Ozric M. you chould, however it have the same problems as rainwater as its still will be polutet with what ever is in the air that will make contact with water like dust or smog. and i guess its quite an expensiv way of collecting water aswell as will only work if the air is humit allready so you whould have no luck trying to do so at greenland or in the sahara desert unfortunatly.the main reason to use one is to remove damp to provent molt in buildings or slowly try to dry books or something like that :)

leave a bucket outside than u has water :D

Then you have that useless self-filling water bottle thing. You're much better off collecting rainwater.

+Susana Godinho It might be OK in a car. But would draw enough current that it couldn't be left running all the time or it would potentially drain the battery flat if the vehicle wasn't running. If you search my videos for rechargeable dehumidifier you will find one of the silica gel ones that has a built in heater so you can plug it in indoors overnight to dry it and it then does a modest job of drying the air in a vehicle.

+bigclivedotcom That would only run when the engine was on or the car was plugged in. I have the silica ones, 1KG bags and those remove about 30ml/day: only good to keep condensation under control while the car is parked. Did you tested the removal rate and capacity for those portable ones on your video?

+Susana Godinho The little peltier unit in the video drew out 200ml in 12 hours of use. Not great for a house, but maybe OK for in a car if it's being driven a lot or if it's an electric one, then while it's plugged in. I might suggest putting it in a suitable container so any water that slopped out of the water tray wouldn't immediately soak into carpet.

It's from the front.

Peltier panels are simple and convenient, but not really efficient. However, it's always worth experimenting.

+micheals1992 You need ventilation or a full size dehumidifier.

I would have thought that by changing the peltier elements and PSU you would have covered just about everything. Is the heatsink clean on both sides? Is the inefficiency during a particular season?

Thanks. All heat sinks and fans are squeaky clean and operate in the same closet, and are operating now. #3 is doing fine, just like the other two did for a couple months. Now those two now produce about 1/5th to 1/10th as much water as #3. I bought 3 replacement Peltier modules from ebay, so perhaps all 5 (original 2 plus 3 new) are bad, but that seems unlikely. I might get brave and move the one from #3 into a bad one and see. I hate gremlins! I'll let you know if I make any progress, so others will know.

Compare the heat sink junctions of all 3 to see if they are the same...Same gap, same amount of heat sink compound and screw torque etc. And airflow. Something might be blocking airflow to two of them.

James, thanks for the input. The heat sinks all look identical and they were all working fine for a couple months. But I didn't replace the heat sink compound on either of those two when I tried new Peltier modules, so perhaps that's the problem. They weren't sticky and the compound did look dry, but I'm not used to dealing with such, so ignored it. I'll get some of that in the next few days and try that -- I'll post back the results. Thanks again.

Well that didn't work. I thoroughly cleaned off the old compound and applied new (per some KZfaq videos). The cold heat sink just barely gets a bit cool, so little condensation on it. I"m wondering if all the Peltier modules have gotten zapped(?). The airflow coming out of all 3 is pretty much the same and the heat sinks all look clean and unobstructed. BUT the airflow is noticeably hotter on the ones that are NOT working so well, and the hot side is hotter than the good one. Not sure what that means, you or anyone have any ideas? Thanks again.

Quite possible but a lot less energy efficient than standard compressor based solutions, you'll probably still need a fan of some kind to move air through the cold side heatsink for anything but local cooling. And a way to dump the heat obviously that exhausts the heat elsewhere outside the building/room. Energy efficiency reasons make them fairly pointless though and even when you want operation that isn't any noisier than fan level noise you're much better off with a central compressor based HVAC system anyway. I do have a convenient mini fridge using this technology that runs on both AC and 12V DC which sees a lot of use during the summer time, it's really quite inefficient energy wise. But it's good enough to take a cold drink from downstairs and keep it cold in my room ready to drink.

+BlueFoxTV Yeah, the ones used for such cooling are a LOT more powerful. These little things are only about 30W, the ones used in computer cooling are usually 100+W. Might be interesting dumping out the low wattage TEC and swapping to something with more grunt (and a PSU to run it, of course).

Sounds like inefficient operation, wonder if the customers prefered it because it seemed more powerful or something... or if the thermostat just wasn't very precise. I once had to look after a computer room that was cooled by a window mounted A/C unit (we don't have these very often in the UK) when it was working properly it dripped water onto the flue of the pizza restraunt downstairs and put it's boiler out. when it wasn't working properly (usually because a colleague had mucked about with the thermostat) you got ice climbing out through the front grill

It is impossible to choose one correct quantity of air flow and coil temperature for every condition so they designed them to work that way when working in colder conditions.

Dehumidifiers that freeze up are not running properly, just like A/C units that freeze up.

Please can you share internal diagram I need this really for my 4 fit box to dehumidifier. It will work in 4 fits box to completely dehumidification within 3 to 4 hours ?

The airflow would have to be matched to the panel. If you have need of greater dehumidification then a traditional dehumidifier may be a lot more efficient.