Ultra-low-energy consumption ultrasonic clothes dryer (opens in new tab)

One day we'll invent a technology device to answer the age old question: "Still wet or just cold?"

I live in a tiny flat in Austria. The vast majority of my washing dries overnight provided I actually get it done around lunch time... even when it's raining. I don't even put it outside most of the time.

If I'm in a major hurry, mostly due to self inflicted procrastination, I'll point a regular fan at the rack as it dries.

I used to hang my clothes indoors when I was living in Europe (some apartments had clever retractable hangers built above the bathtub), and even when raining they would dry in less than a day.

Can you put your clothes on a fire escape? Or in your bathroom (works great if you have a bathroom with a window).

Sunlight isn't an overkill. It's a great germ killer (You have to be cautious not to leave them out for too long, lest the UV/Heat damages the colours).

You can use a lot of detergent to remove the last bacteria; but household detergents are a big source of water pollution.

Not sure why everybody assumes fusion powered implies direct sunlight.

Drying clothes in the shade is also powered by the sun, because the air only has "unused" moisture capacity because it was heated at some point. To repeat the cycle forever it will need to cool down and then be heated again.

Years ago (on Mull), I saw someone selling drying tents: basically, a large tent with open ends and clotheslines inside. The shape apparently draws air through the tent. They said that even on cold, wet days, clothes dried quickly because of the air movement, and of course, no energy consumption.

Never, ever seen one since, and a quick web search for 'drying tent' shows up nothing but kit for pot growers.

Bed-wetting children get cheap blankets and mattress protectors (plastic sheets), not duvets!

I'm at the top end of Scotland - we can barely dry towels and trousers, nevermind duvets.

I feel you.

If you use an air conditioner, you can do it the Chinese way. In humid cities people hang their clothes near the AC exhaust, since it is "free" hot air. In a super humid city I've seen clothes dry that way in only a few hours.

Oh really? I thought those were just little balls of lint and fabric. Now I feel like a jerk.

Probably about the same as wearing your clothes outside I'd imagine.

Hang inside out.

A big (practical) problem is that you might not be around to take the clothes of the clothline in time and they end up 'roasting' for extra hours/days. Sunlight definitely does fade the colors.

We dry ours (2A+2C) inside on hanging racks, but it takes up a fair bit of space. In a smaller house, we'd have no chance.

Why on earth is this being downvoted?

Yeah, thanks for the comment on the condensation.

The output pump would really need to mostly pump water and vapor at the input and liquid at the output, but not to very low pressure... even a peristaltic might be doable (no rotary vane/blower needed). It was just a thought, I used to rotovap too so running through the calculations seemed like a fun idea.

But then you won't be able to dry your white clothes because your color piezo needs replacement.

You know what I want? A lemon law that states that major appliances need to run forever. Literally something that says, "This device must run without professional service for 25 years." Forget energy star stuff, 100Kwh saved a year is meaningless because we can always optimize powerplants. Stop building disposable 100LB metal boxes that have to get scrapped and thrown in a landfill. If the device fails earlier than that, the company has to replace it and pay a large fine for producing faulty equipment (larger than the profit from the device by an order of magnitude).

Then just allow people to rent the devices (which would obviously cost more) rather that have to buy them outright.

This is the main reason.

The difference in the longevity of my clothes -- same exact articles, same brand, same material, thickness, size and stitching -- from switching from a "hotbox" dryer to condensation dryer was initially amazing. No more did cuffs and collars start to crack and fail, nor did my shirts slowly develop small tears.

The latest (2014 is when they really started to hit the market) heat pump dryers dry clothes even cooler still, albeit since they're new tech they're quite a bit more expensive right now.

In Europe, a "condensation dryer" is so common, they're just called a "dryer", with no differentiating term. Additionally some countries (Switzerland I think) I believe don't even allow hotbox dryers anymore (and their needed conduit and vents) as part of fire/building code. Condensation dryers simply have a high quality lint filter (that truly does trap it all) and vent to atmosphere, since they just use a heat exchanger.

All while using far less electricity than simply heating things resistively.

What to batteries have to do with clothes dryers...? You're comparing a consumable good to a household appliance. Household appliances are expected to last 5 years. 7-10 is pretty normal.

Batteries not lasting long is considered a limitation of our current battery technology. This limitation doesn’t currently exist for typical clothes dryers.

There’s no reason to introduce a new limitation unless the technology makes up for it in other ways. Having to replace a clothes dryer every two years would require the technology to be very good to justify such a burdensome task.

Because dryers are expensive appliances. If they're going to make one that only lasts one tenth as long, it better cost one tenth of the price too.

This device is supposed to be eco-friendlier than a hot air dryer.

The benefit reduces if you have a consumable component that needs changing, especially with the amount of e-waste that goes to landfill.

Arranging large appliance delivery and disposal is a pain in the ass when you've got full time jobs to deal with. Don't want to do that any more than needed.

Batteries are also (relatively) cheap and easy to replace.

If my dryer was $50-$200 and could be carried in one hand, I'd be (grumpily) okay with it only lasting 2 years.

As if I could ever find a clothes dryer in china.

>> sonically baffle any outlet

Good point! The water vapour needs a way out. That means a direct air path between the fabric and the outside world. They cannot seal the entire thing in a vacuum bottle to deaden the sound. I see a 50' pipe full of baffles, a giant truck muffler, between this thing and anyone with eardrums.

Conventional driers also cause significant wear to clothes.

Give it a try: "600 Hz Sine Wave Sound Frequency Tone" https://www.youtube.com/watch?v=ERHcqYNLHyg

and 500: https://www.youtube.com/watch?v=GlEfshsoyZk

If that really is the range they are targeting, this product is doomed. That will be one heck of a noise to cancel. "Soundproof box" is right up there with perpetual motion, zero-point energy, and spherical chickens in vacuums.

That (the 600 Hz) is the modulation of the ultrasonic signal from the transducer...I am not sure if modulating the underlying signal at that frequency has a similar auditory effect as a simple 600 Hz sine wave.

Indeed that's what it says. That's neither ultrasonic nor easy to block with reasonable quantities of sound dampening materials.

They also directly mechanically couple the transducers to the fabric. You need as much area of transducer as fabric you need to dry, unless you have some automated way to place the fabric on the transducers sequentially.

To get the effect they want they have to use high frequency 30-40kHz (as in name, ultrasound). They modulate it with lower frequency (which probably splits off bigger water globs) for better efficiency or something. You won't be able to hear the modulating signal as you are not able to hear the carrier frequency.

That's definitionally not ultrasonic, so I don't think that's the relevant frequency.

I'm not sure that we can make an accurate judgement based on that because it's going to depend on the mic they used, audio codec, (and less relevantly), speaker setup and hearing of listener.

I don't understand why this is such a valued aspect of dryers. All clothes coming out of the dryer for me go right into my drawers / hanging. They don't get worn at the very earliest the next day. I rotate everything so I'm not just wearing the same socks and undies over and over again, so the vast majority of the time they don't even get worn then.

Is the psychological effect of folding warm clothes rather than cold really that powerful?

I didn't realize this, but yes, this is absolutely true. I wonder how many people would actually be willing to pay a premium on having their clothes warm when coming out of a dryer.

In at least WA, NSW, QLD and ACT you can go on time-of-use residential tariffs.

And driers (and washing machines - which use a considerable amount of energy particularly if they heat the water internally) typically already have timer-start functions.

They mention that in the video.

It also mentions that they're thinking of creating a tumble/drum dryer with these piezoelectrics. As opposed to a traditional tumble dryer that spins to aerate the cloths, I think the spinning motion would instead be required to pin the clothing against the piezoelectric lined drum (though I imagine it would need to stop and change direction periodically in order to expose different areas of the fabric to the drum wall).

"denaturing" does sound scary and bad -- It's a dumb way to describe what happens in any cooking process.... it sounds like turning food into plastic before eating it (take the nature our of it) LOL.

Anyway, there are real health risks according to the World Health Organization:

"Food safety: Food safety is an important health issue. In a microwave oven, the rate of heating depends on the power rating of the oven and on the water content, density and amount of food being heated. Microwave energy does not penetrate well in thicker pieces of food, and may produce uneven cooking. This can lead to a health risk if parts of the food are not heated sufficiently to kill potentially dangerous micro-organisms. Because of the potential for uneven distribution of cooking, food heated in a microwave oven should rest for several minutes after cooking is completed to allow the heat to distribute throughout the food."

That sounds like nuking the surface of the food then waiting for it to cook after it has ben microwaved which may or may not fully achieve thorough cooking.

http://www.who.int/peh-emf/publications/facts/info_microwave...