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Does anyone make them already?
I dont mean those that just switch off when washings dry, but more along the lines of controlling (and saving) heat input to just achieve optimum humidity and therefore dew-point given ‘cold’ inlet air temp.
Sorry I know its a hell of a question but thought as I was logged in….
Something I’ve been thinking on for a while as I have a condenser dryer and kitchen gets like a damn sauna. Except it only has two settings and heat control is not dynamic.
I dont think it would be that hard to work out curve on psychrometric chart and programme a pic to operate a pid heater controller based on a couple of k-types and a humidity sensor (18 quid in RS)Anyone agree or tried it already?
Re: Really smart tumble dryers?
About the best you’ll get are “sensor” dryers that detect humidity within the drum. Apart from that, not that I’ve seen, dryers tend to be very dumb devices.
K.
Re: Really smart tumble dryers?
This is supposed to be clever:
http://www.crosslee.co.uk/cl847.html
Penguin45.
Re: Really smart tumble dryers?
Yes it does look nice but dependent on the setting selected still. It doesnt appear to control heat power, just time (low bake or fast bake).
Given the high temps and the crappy small heat exchangers manufactures use, they get so hot its a wonder that any water vapour condenses. Especially in my sauna like kitchen, especially without taking into account the rise in ambient air temp.
I thought perhaps Bosh or Miele might have one perhaps. Think of all that heat energy wasted. The Gov keeps moaning about global warming like its ‘our fault’ forcing millions of homes (flats) to be built without washing lines, and rely on manufacturers to save them power. SadRe: Really smart tumble dryers?
Ye Penguin but on the A rated program (if memory serves me) it takes about 8 hours to dry, hardly stunning performance. Since most people with kids have several loads to do at once, for me, it pretty much renders the function useless.
The big factor you’ve missed CD is the cost. Quite simply most people think that a dryer, washer or dishwasher is a “white” box that sits and does a job, they all do the same job and perform in the same manner. Far from the truth, but that appears to be people’s perception of appliances. Price is not the only difference.
So when you can buy a tumble dryer for ~£100 why pay four times or more for an appliance that does the same job? You have to show either considerable increase in performance or a saving on total ownership over the lifespan.
I agree with you on flats, but they tend to have washer dryers to pass building regs as that satisfies the “drying facility” bit, even if the performance does not satisfy the owner.
K.
Re: Really smart tumble dryers?
Of course they would probably cost ‘a bit’ more, but that shouldnt be the criteria to stop in progress or better design if its possible. It wouldnt be very hard to do or implement either if people just damanded better than the crap they are happy to fork out a couple of hundred quid for for so long.
Big builders like Crest Bovis, Barret etc dont need to pass building reg. The NHBC pass everything they build and tell buyers to make a claim if buildings not right. Also worth noting is that many of the tousands of new homes built and and planned are under control of the Housing corp Social housing (new Govt private empire) and whos going to enforce regs for them? The government?
But this is not why I asked the question. I’m happy to play and modify my own machine if need be. I just wanted to hear if its been done.
Re: Really smart tumble dryers?
Just a point….
Dryers don’t usually detect humidity as such. The electronics puts a mv through sensors around the tub and actually detect conductivity.
Thats why there not clever and its full bake/half bake and not very efficient. Their crude!
Crosslee do it using the 3 lifters(paddles) and insulate the metal strip from the tub quite cleverly. It works well enough but is not humidy(as in air measurement) controlled.
Kevin
Re: Really smart tumble dryers?
Yeah thats what I guessed. Full on heat untill resistance drops.
That system or something like it, would still be needed to measure how dry washing is, and especially as RH sensors were never that good at low levels. So really any system that ‘controls’ the heat can only be good. Most likely save a fortune.I’ll email crosslee and see what they have to say.
Re: Really smart tumble dryers?
Drying without heat should surely be the goal when on realises that heat-pumps and thermo-sensor dryers rely on even more energy to operate?
After all, washing placed on the washing-line in a howling gale will dry very quickly and at very low temperatures and very low humidity. Therefore, with the existing size restrictions of modern tumble dryers, you simply need to increase the size of the fan and/or the free air flow to achieve the same result. But instead of needing 2.5Kw to dry a 5Kg load in 60 minutes….a nice big fan system and a 400 watt motor should do the trick in much less time. 💡
Nothing smart required !! 😉 Only issue I can foresee is, ‘noise’ might be the only problem, as hurricane force winds are a bit noisy 😀
Re: Really smart tumble dryers?
How can a couple of sensors use as much or more as would be saved.
Your talking a couple of milliwatts of power for a few sensors???I wasnt sure how to take your post at first, but I’ll give you the bennefit of doubt. You really must look up dew point and try and understand what relative humidity means. (without meaning to sound arrogant)
I do agree with the washing line bit wholeheartedly. (Even with all the ironing) but you tell all the retailers, customers, Govt and even builders, and everyone that wants to speed up drying times, reduce costs, save energy and keep the kitchen at a reasonable temp.
But to be clever washing wont dry in the rain or when outside air temps low and RH are high. (Assuming atmospheric pressure remains the same)
All ready been down the heatpump road. Not going to happen. Prices even if hp becomes workable are still ridiculous.Regulating heat, optimizing conditions in dryer seem the best / simplest /cheapest / practical answer. Cant believe its not on the shelves.
Or taking your suggestion I could ask the missus to blow on it.
There’s a thought!Re: Really smart tumble dryers?
Some sensor dryers use thermistors in the exhaust the air intake and at the heater they determine when the the load is dry as the exhaust gets hotter they are oviously dryer, others work on the conductifity method as a load drys the resistance gets higher hence the contorls know how dry, only drawback with this if you want to dry a small load the most off the airflow misses the load causing the sensors to dry out resulting in load not drying.
Re: Really smart tumble dryers?
All too complicated, there is a much simpler solution.
In the good old days everbody had a clothes airer fastened to the ceiling, raised and lowered by a rope and pulleys. Heat from the fire range would dry the clothes overnight no problem, condensation no problem, it all went up the chimney.
Modern solution, ceiling full of clothes airers, a decent dehumidifier with humity stat, by setting the stat you can dry the clothes from damp to bone dry. Only uses a small amount of electric, and more heat given out than electric used.
For the more affluent, build a £15, 000 conservatory with a vented peak and with tie rods strengthenig the roof. Hang the washing on the rods overnight. Condensation goes out of the vent, no electric used.
Ace.
Have to go now, some blokes are hammering on the door, seem to be carrying a white jacket with buckles and straps.Re: Really smart tumble dryers?
Had a reply from Crosslee.
First off my impression is they thought that heap-pump dryers were the focus (why does everyone still think these have a future?) But the stumbling blocks were damp airborne lint and longevity. (As if they care)When pressed on the simpler heatcontrol idea, It was such an old and obvious idea ( of course) but how could any humidity sensor avoid the damp airborne lint. Even a simple thermocouple on the heatexchanger would be an improvment, but clearly while theres an excuse why bother basically.
Like I said they dont give a toss and are happy to sell simple crap to simple people.
Looks like I’ll have to play with my own. What a shame though.Re: Really smart tumble dryers?
clever dicky wrote:Looks like I’ll have to play with my own.
I suspect you knew all along the outcome of that anyway? 🙄
A domestic motorised wind tunnel, heaterless form of drying clothes is the only true eco-friendly answer that would be adaptable within the 820 X 600 X 600mm box I reckon. 😉
Go away and design within that criteria my friend and your fortune is assured 😀
Re: Really smart tumble dryers?
Mate I totally agree. You ARE spot on. But…
In a sealed box the air would soon become saturated, and water would have to condense befor clothes would evaporate again. Which would limit effectiveness so youd then have to heat. I spouse it would have to be open ended to work properly so youd need some ductwork from one side of the building to the other, or a chimney to more fresh dry air. Another way could be to motorise a rotary washing line. Now theres an idea.But really all good comercial / industrial drying chambers use the same principle.
Imagine a LARGE chamber, 30ft x 15ft. Stick a false ceiling in and above it near the middle. Stick in wall to wall, high power fans and heaters. The hot air blows accross the false ceiling to the front wall, deflects and goes toward the back of the chamber through whatever needs drying, racks of sweets, bricks, even boilees, where the enormous great FO humidifiers I’ve spoke of before are waiting to strip out the water from the wind. Then goes up above the ceiling and starts again.
Not what youd want in your kitchen though, a smaller version would mean back to damn heatpump dryer again.Oh well! looks like I’m staying poor… 😥
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