The thermoelectric dehumidifiers are incredibly inefficient. Maybe better suited to a camper where they could run directly from solar during the day.

@STONEDay

Жыл бұрын

High got sent one for freview. Put it in my 1m x 1m grow space. All it did was raise the temperature. It was unable to remove enough moisture to be any use in a garden. Then high thought I'd try it to dry some flowers...they got bud rot from excess moisture. Doh. Thinking about converting it to a water chiller by putting water blocks on the 2 TECS. Do you think it would it be work the effort?

@midinotes

Жыл бұрын

Definitely, probably under 3% efficient. The biggest challenge is you need a very smooth D.C. supply to power them, as any ripple will induce resistive heating in the p-n junctions. You also need good thermal contact between the heatsinks and the module, so a thin but consistent layer of heatsink compound. The modules and thermal interface tend to deteoriate over time, but it's a relatively inexpensive and solid-state option to provide localised thermal pumping at small scale. Seems relatively good value though, power supply looks decent. I spent many years working in the field of thermoelectrics - although more using them in the opposite sense i.e. generating electricity from heat flowing through the modules. I wonder if this dehumidier has protection against the fan failing? The modules will quickly deteoriate if they exceed 150 degrees (they usually use low melting point Bismuth Telluride). Interesting to know if you do use it for its intended application and how effective it is versus the power consumed.

@JulianIlett

Жыл бұрын

I suppose dehumidifiers have a dual role - taking moisture out of the air - and acting as a low wattage heater. In respect of the latter, they're just as efficient.

@evanleebodies

Жыл бұрын

....and the cold side heat sinks accumulate a lot of ice in a cooler spaces, it could do with an auto defrost function-I can feel an Arduino project project coming on

@nigelanscombe8658

Жыл бұрын

My that’s confusing. 🤯 Watching Julian and seeing comments from Big Clive.

I have one of them working in restroom. It works pretty decent.

I have the smaller one that's been running almost non-stop for several years now, and it's not useless. it's meant for smol, tiny spaces, like a closet or bathroom. Less expensive to operate than those disposable containers sold at pound/dollar land/stores. A lose connection on the power input is the only flaw I've noticed. Cheers.

The peltier module from these can be used to generate electricity, I had one side on a heat sink in water and warmed the other with a flame and it was enough to run a small radio. 👍😎

An impulse purchase? From the middle of Lidl? Whoever heard of such madness!

I've purchased a few of these to generate water indoors for my seedling starter garden. These dehumidifiers along with my led growlights are powered by my 12vdc garden solar generator. Everything is on a 12vdc timer control. So far it works for this application, but not for my outdoor garden. Yet!

With the present eye-watering cost of electricity this type of dehumidifier only makes sense if you can run it on "free" electricity, e.g. from solar panels. It would be useful in a shed or caravan fitted with such panels as a damp/mould preventive measure. Domestically a compressor type make more sense economically if it is to be mains driven.

Can't wait for someone building a DIY dehumidifier using desiccant wheel of silica ! ;-)

@linusmorell9261

2 ай бұрын

Why should the make their own? When you have Munters who was the inventor of the dessicant wheel on the market?

That little machine is what I have in my campervan, it works reasonably well but has a habit of creating inch thick ice if left on continuous, a timer set to intervals of 3 hours on, 1 off seems to stop the ice forming.

The innards are almost identical (the power supply circuit is actually a external brick) to a dehumidifier I got a few years ago. I had it in a small storage room in the basement as it was really humid down there (the water drips from the brick and cement walls and mold is a real problem), the chemical dissecants were useless due to how little time they last, this little fella removed roughly 2L in 1 week or so (turned on 5~6h per night). One issue I have with mine is that it builds up ice on the coldest and dampest days, I use a plug with a timer that sets on/off 15mins intervals for 24h and set it to pause every hour or so to allow it to defrost. It did broke once, the fan stopped working and it overheat quite a bit, there is a thermistor of sorts in the middle of the large hot heatsink that prevented worse damage (the plastic actually melted a little) and after replacing the fan and reapplying thermal compound, it was up and running again ... great little work horse, but of limited use if the room to be used is much bigger than a large wardrobe.

The heat pumping TEC exploits the Peltier effect. The electrical generation of a TEG uses the Seebeck effect. And yes, they can each do a similar job to one another, but I believe there are efficiency losses substituting one for the other, and they are horribly inefficient to start with. They are neat though :)

These things have their uses in small areas, and are OK to keep mould from growing in inbuilt wardrobes or cupboards, also providing a slight heating effect. They are very inefficient compared to a full sized compressor or desiccant disc type, and anyone hoping for it to replace one will be sadly disappointed. With the smaller type I found the microswitches can't cope with the current and I had to replace them and add a relay.

Thks very informative. I just brought one but it’s not collecting any condensation from my bathroom even after prolonged used. Will return it

I have one of these style dehumidifiers on the top of my toilet with the drain going into the tank.

Actually a good thing it draws the cold dry air through the hot heatsink. Improves the efficiency of the peltier a little bit...

very well explained, thanks!

I definitely think they are interesting, if they were more efficient I think they would have a greater use case. Since they have no moving parts they would be fairly nice in terms of maintenance.

Older houses here in NZ use the compressor type as we do have high humidity. Because many houses still use single glazing and metal frames, water pisses down the windows and frames by the gallon. Even with 2 or 3 de humidifiers many homes here are still damp and cold. Couple this to poor or no insulation, reminds me of the UK in the 50s.

@joinedupjon

Жыл бұрын

The UK hasn't changed much since then for renters

@barrieshepherd7694

Жыл бұрын

Yep - I remember the ice frozen on the inside of the bedroom windows in winter 😂😂

I had two units like this, but the electrical components were in sort of their own electrical box along the electrical cord. Those components cooked themselves (and the box) to death in both of them. When I was removing one to see why it broke, the box crumbled in my hands due to the wear from the heat. In both of them, the big capacitor blew.

A small size can be useful for a musty closet or keeping your camper/caravan dry.

👍 Great 👍👍👍👍

If most of the internals run off 12V , can you bypass the mains, and run it off your solar ? and keep your shed mold free

Dehumidification is all about lowering absolute humidity. (e.g. from 20g/cubic meter to less than 10g/cubic meter) To do this, the air must be cooled below the condensation point and this has the advantage that the room is also cooled (but important: heat and water must be discharged to the outside. In damp, cold autumn weather, the heat output of the cooling unit is not sufficient; external heating is required.

Julian , You need to set emissivity on the thermal camera to 0.3 as aluminum surfaces are not black bodies like most materials. Temperatures will be 2-3 times out of whack and look wrong on temperature map.

I have one that is from japan I use it for small space duct. It only has one TThermoelectric tile however it has a changing led and touch capacitive buttons.

Would they be any use in a bathroom? Ours doesn't have an extractor vent, has two outside walls, and gets a bit cold until the shower is running. Wondered if it make any appreciable difference to temperature generally, and removing moisture after the shower. Appreciate you're not supposed to have mains voltage in a bathroom (we can run power from the airing cupboard which has a 3-pin mains socket). All that water (inside the unit) near all that circuitry worries me too.

curious and curiouser, a heat pump pelter unit that dehumidifies the air as it blows out more warm air to soak up more moisture to condense out more water to heat more air to get sucked in to release more water soon you will have a small amount of super dry air circulating 🙂

@JulianIlett

Жыл бұрын

It's a virtuous circle :)

@andymouse

Жыл бұрын

Squeak !

@fredflintstone1

Жыл бұрын

@@andymouse Cheesey!!!!!!!!!!!!!!!!!!!!

now I want to understand how a peltier element works

If you want a DH for winter use in the UK you want a desiccant type as they operate well at low temperatures. Compressor efficiency really drops off below 20C. The thermoelectric are useless for DH a room but they can be useful for smaller spaces like a cupboard or caravan especially if you run them from a solar panel so they are effectively running for free.

@phil955i

Жыл бұрын

That's what we run in the Winter, two desiccant type dehumidifiers, one downstairs & one upstairs. They also have the benefit of adding a little heat.

@caskwith

Жыл бұрын

@@phil955i Yes that makes them perfect for winter. Any other time you would begrudge the higher running cost and excess heat they produce.

@phil955i

Жыл бұрын

@@analogueavenue 👍 we've not put our heating on yet, mind you it has been comparatively mild for November so far. As you say, they give a base temperature & keep the mould & damp at bay. The windows remain condensation free too.

@caskwith

Жыл бұрын

@@analogueavenue It would be nice if I could do that. I could happily just run the DH if they kept our flat at 18, no need for additional heating at all, that's warmer than we keep it even with heating on.

I have the same thermal camera, and it doesn't discharge its battery just sitting in my drawer. Weird that yours do that!

We could say that this Thermoelectric Dehumidifier is also a small electric heater! what is the part of the 70W used for? could you do some calculation.

I reckon if they added a small heat exchanger so that the cold dried air leaving the cold heat sink pre-chills the incoming air, it would perform a lot better.

@matthewwakeham2206

Жыл бұрын

You'd want to pre-warm the air to increase the temperature differential between the now warmer air and the cool side of the peltier. I don't know how much it would improve the efficiency though.

I expect that the PSU is not 100% efficient so 60W’s out at 12V will be higher on the input. So if it’s 85% efficient the mains power would be around 70W’s At least you can put the water in your iron as distiled water and put it back in to the air while you iron.

@JulianIlett

Жыл бұрын

Ah yes, good point about the power supply efficiency.

@TheEmbeddedHobbyist

Жыл бұрын

@@JulianIlett One must never forget about the fish in sea. ;-)

@fredflintstone1

Жыл бұрын

@@TheEmbeddedHobbyist Meow!!!!!!!!!!!!!!!

@jaro6985

Жыл бұрын

Yeah dont use the water collected from these, very dirty.

@alexatkin

Жыл бұрын

@@jaro6985 Oh come on, you don't want a bit of Legionnaires' disease?

so now that summer is over antminers probably dont cut it for getting the shed dry thus the dehumidifier?

@JulianIlett

Жыл бұрын

There's no way around the fact that heating a shed is expensive and pointless :(

tecs will produce power also if one side is kept cool and one side hot

Isn't the 'cold heatsink' a 'coldsink'?

No filters then to stop dust buildup?

@JulianIlett

Жыл бұрын

Dust isn't really a problem in this design. It will simply wash off the cold side heatsink with the water droplets.

@julianchamberlain5399

Жыл бұрын

@@JulianIlett what about the warm side? If that gets all clogged with fluff, which is typical in a laundry room? I use a refrigerator type in the utility room. Do you think the peltier dehumidifiers are more efficient? As in more water collected against electricity used? My daughters after one and I suspect she works be better off with an ebac.

@JulianIlett

Жыл бұрын

Yes, I expect a film of dust will eventually coat the warm-side heatsink and fan, but I can see it working OK for the 3 years of the warranty. No, thermoelectric dehumidifiers are less efficient at extracting moisture from the air.

@johnnodge4327

Жыл бұрын

@@julianchamberlain5399 A peltier heap pump dehumidifier is orders of magnitude less efficient compared to a refrigeration type dehumidifier.

@alexatkin

Жыл бұрын

@@julianchamberlain5399 Even a refrigeration type often tell you NOT to use them in a laundry room, you need something more purpose built for that.

Who wants something that generates heat on a hot, sticky day?

@JulianIlett

Жыл бұрын

We don't really get them. In summer it's warm and dry, in winter it's cold and wet.

Gubbins?

So basically if Mel Gibson owned this product he would say, I deserve to be cold first.... before the effing jacuzzi

terrible efficiency i bet

Your TEC from part number seems to be 12xx marked, so likely a 12V model, so if you are using it on 3.7V LiOn cell is probably still inefficient. Normally at leastv20°C difference hot to cold should be achieved. There are also multistage TECs that at diminishing returns get 30°C and more. Each stage stacked achieves slightly less per stage as it also must drive heat of the lower stages, so 20 first stage 10 second stage for 30 and mere extra 5°C at third stage, meaning beyond that too little to bother. Heat pipes/heat sinks can make minor boosts, but cost wise also diminishing return for money. Two stage coolers are probably optimum for Max cooling around 30°C. Important is not getting cold side frosting, icing over when going sub zero. Many Astronomy cameras use multi-stage cooling of the CMOS or CCD camera sensor for noise and dark, leakage, current that make the camera less usable on very long exposures. There however the cold side is in a sealed camera cell, with desiccant for no moisture at cold sensor side, so no fogging, frosting or ice formation issue. However multi element TEC used fir small portable and camping coolers for freezer section do suffer loss of effectiveness as frost and ice forms. By the way rain fall does not automatically mean very high humidity, and not lots of actual water vapour in the air, only dumping droplets water depending on ambient humidity suffering some evaporation as they fall. In dry conditions, the droplets may completely evaporate as they fall none reaching the ground at all so frustrating in draughts for farmers preying for and thinking finally some rain, to get none on the ground after all. The amount of water in the air is VERY temperature dependant. 80% at 30°C is hugely higher water loading, as grams or milliliters per cubic meter of air. Than 80% humidity at 10°C. Dew point is the critical parameter of air at maximum humidity . Dew point near 0°C is very low water level, but Dew point at 30°C and above, is tropical stifling humidity, making breathing difficult, feeling like you are starting you are drowning, just breathing. At lower temperatures FOG is the point when air is at 100%, so by general impression London is often in 100% humidity as can be the bathroom when showering, with over worked ventilation fan. These small dehumidifiers are not really intended for home or even sizable room dehumidification, but if camping, caravanning, even in your car travelling in humid conditions can make quite a difference to overnight comfort. Biggest problem being the heat generated, as often both temperature and humidity make sleep uncomfortable. One solution on the smaller unit with single top vent is directing the warm air out of the local space with a piece of the foil air duct, a bit harder for that larger unit with vent on both sides, so need two duct pieces taped on leading outside.

Dehumidifier in winter? Only in England. It's probably raining there right now... When it's cold outside, the humidity is the first casualty inside.

This thing is so inefficient it should be illigal...

@JulianIlett

Жыл бұрын

As a small room heater it's 100% efficient :)

@alexatkin

Жыл бұрын

@@JulianIlett Yeah but 70W heater? I get more than that from turning on the TV. Or get an old PC and run something like Folding@Home.

Silent night went bankrupt a few years ago and the liquidators sold off the name Silentnight as brand name to the highest bidder, it is no longer a company but a Brand name only and is a bit rubbish today because it is budget rubbish.

Useful if you want to overclock CPUs / ASiCs / FPGAs However A Energy hog However intriguing of you could Use TEG Seebeck To Recuperate Energy OVER TIME For a Run Event (mins ~ hours ) (Even with the inefficiency losses A Free run From Waste heat due to other inefficiency's)

These never seem as good as either the normal type of dehumidifier.

@johnnodge4327

Жыл бұрын

They aren't. A compressor based refrigeration principle dehumidifier has well over 100% efficiency. An electronic dehumidifier is around 10% efficient, so by comparison is horribly inefficient. Unless the power for a peltier system is coming from a free source of electricity like solar, then they really aren't worth the effort.

Pitty they are so energy wasteful.