How the hell does this work?

[toggleswitch2]

How can a condenser dryer be a "B" class, while/whilst a vented dryer is a "C" class?

1-vast quantities of heat are added to indoor space in the summer with a condenser. Here where cooking is needed in sumer that is not a benefit.

2- I was under the impression that condenser dryers use MORE energy per KG (or LB) of laudry to do the same job as a vented one.

 

[dj-gabriele]

No longer 100% true

Condenser dryers use more energy than a vented dryers but only if you compare appliances in the same energy class (C).
If you get a B or A class dryer it will use less energy than any vented dryer around and since all the A class dryers are heat pump driven the energy waste is less than half.

You can have a look at this article on wikipedia that isn't that bad. If you can read Italian I could send you a booklet of ENEA (our National Agency for New Technologies, Energy and the Environment) about energy efficiency and energy classes.

About using machines to dry in summer: to me it should be outlawed! Here stuff hung outside is done in 30 minutes after a spin of only 800rpm on my washer! No dryer would be so fast!
But, to returning to your point: by using a condenser dryer one dumps anything between 2 to 6 kW of heat in one's dwelling, if he were to use a vented dryer:

Using this values for computation: (for summer)

specific heat of air: 1010 J/kg/K
outside air at 32°C
inside air at 25°C
exhaust air volume 340 m^3/h (200 cfm)
density of air 1,2 kg/m^3
1kW = 3.600.000 J
run time of 2 hour

1010*(32-25)*1,2*340/3600000*2= 1,6 kW of wasted "cooling" energy... the vented dryer sure wins in this side! (but again, why use a machine when you have the summer sun?)

doing the same calculation for winter we have:

specific heat of air: 1010 J/kg/K
outside air at 0°C
inside air at 20°C
exhaust air volume 340 m^3/h (200 cfm)
density of air 1,2 kg/m^3
1kW = 3.600.000 J
2 hours run time

1010*(20-0)*340*1,2*2/3600000=4,60 kW

That's an awfully large quantity of energy to dump outside in winter, not counting the same amount of energy is needed to dry the clothes, in a condenser dryer all the energy would be dumped inside one's house and actually save on heating costs, with a vented you have to heat the air twice!

A final note on water condensing washer dryers and the "new" Hoover water condensing dryer: these machines have no effect on inside temperature as they dump the heat in the sewage water.

After this I guess we can agree that an efficient condenser dryer is less energy intensive than a vented one. Hope to have been clear enough!

http://en.wikipedia.org/wiki/Energy_label

 

[favorit]

About combos I do agree with Launderess. Even a Miele combo is ... a compromise. It is (a lot of) money not properly spent : separate W and D units cost together about 500 € less than the combo, not to mention they work better

Gabriele are you sure that combos are more energy efficient than separate W and D ??
A bigger drum allows more efficient tumbles and air flow

The euro "A" label applies to them if used as a washer only. when used to wash and dry they get a "B" in the best case.
Not to mention that combos even use water to dry.... (modern dryers don't).

Toggles the new heat pump dryers are really energy efficient.
The heat pump works more as a dehumidifier rather than as a heater. So they dry @ lower temps and can manage even very delicate fabrics as wool and silk ( yes they have separate motors for drum and fan )

this is the Candy combo I had [thanks toMatchboxPaul 4 the pic ]

 

[dj-gabriele]

@favorit

I just made homework and here are the results!

Have a look at this (you mentioned Candy... you get Candy!):
http://www.candy.it/prodotti/scheda_prodotto.asp?id=GO W 485 D&id1=843Wash and dry 8kg: 5,44 kW (0,68kW/kg) (+ 50 L of water for drying)

http://www.candy-domestic.co.uk/products/details.aspx?pid=149Wash 8kg: 1,52 kW (0,19 kW/kg)

http://www.candy.it/prodotti/scheda_prodotto.asp?id=GO DC 78 GT&id1=845Dry 8 kg: 4,4 kW (0,55 kW/kg)

If you get a C class dryer:
http://www.candy.it/prodotti/scheda_prodotto.asp?id=GO DC 58 F&id1=845Dry 8 kg 5,1 kW (0,64 kW/kg)

Wash & dry (C class dryer): 5,1 + 1,52 = 6,62 kW (0,83 kW/kg)
Wash & dry (B class dryer): 4,4 + 1,52 = 5,92 kW (0,74 kW/kg)
Wash & dry (A class washer-dryer): 5,44 kW (0,68kW/kg)

On a final note: have a look at the new water condenser top loading dryer!
They had a vented top loading dryer since at least 1998 and they discontinue it in favour of a water condensing one?!?! Unbeliavable!
http://www.candy.it/prodotti/scheda_prodotto.asp?id=CST W539&id1=845

 

[chestermikeuk]

Frigidaire

Hi Ken, glad you enjoyed your vacation, its a lovely place to visit, did you get to the local village square & markets!!!

I remember selling the similar Frigidaire version of this machine, slimline top loader with built in dryer, they made them in 500rpm & 800rpm versions, but then the dryer had three elements (rather like early aristons) that came on to produce a residual heat in the drum (think bake) and then used water to condense the steam!!! took about 3+ hours for a complete wash rinse spin & dry with just half a load!!!

 

[toggleswitch2]

ah heat-pumps! Thanks. I had forgotten about those!

~About using machines to dry in summer: to me it should be outlawed!

Let's not forget that many line-dried items need to be ironed. That takes energy. So maybe machine-dried in summer is less of a sin than we expect it to be!

So If I were to vent an electric (vented-style) dryer into my house would that be more or less efficient than a condenser of the non-heatpump variety? The humidity released inot the house is the same as if one were hanging the items to dry indoors.

 

[toggleswitch2]

should read "into" not "inot"

 

[favorit]

Toggles you're right. Vented dryers are usually more efficient than classic (no HP) condenser ones. Not a case all commercial ones are vented.

Condenser technology has been developed here in EU to push dryers in those countries as mine where dryer vents in buildings were/are U.F.O.

Until 10 years ago here in IT dryers were a small niche product (little choice even in big box stores). Today there's plenty and they are all condenser (except some budget model)

Expecially in summer, condenser units are less efficient.
Room air isn't cold enough to let the condenser do its job properly
Otherwise those who have dryers in the kitchen prefer condenser ones. Drying in a vented unit while cooking onions would take laundry back to the washer

Anyway gas dryers are the most energy efficient (and faster). Here nearly all commercial dryers are gas heated. Pity, since Miele discontinued the T 478 G, here we haven't any household gas dryer available no more

http://www1.miele.de/de/en/press/149.htm

 

[toggleswitch2]

~Drying in a vented unit while cooking onions would take laundry back to the washer

Now that makes PERFECT sense! I've done it and it's bad news! I'm no longer one for hanging laundry to dry in the bathroom either.

 

[hoover1100]

I don't understand the idea that tumble dried clothes are less creased than line dried.

I've found completely the opposite is true, especially on jeans, shirts and the like.

It's not just smaller capacity dryers either, from huge American style commercial dryers all the clothes seem to be far more creased for me. Line dried the creases just seem to fall out.

But either way, if an item needs to be ironed it needs to be ironed irregardless of if it has been tumble dried or line dried, dress shirts always need ironing from my experience, no matter what techniques you use or how careful you are, same for bed linen, unless is isn't pure cotton.

I don't have a dryer full stop in my current house, don't have to iron anymore than when I have used a dryer, and my clothes are no less creased.

The idea of using a dryer in warm weather seems absurd to me, lol.

Matt

 

[dj-gabriele]

@toggleswitch2

Well, using a vented dryer indoors would be around the same as using a condenser one plus the added lint and moisture, if one sticks to the Eurolabel values (or this Candy -again- vented dryer) you have:

http://www.candy-domestic.co.uk/products/details.aspx?pid=153
4,5 kW for 8kg (0,56 kW/kg)

that is just a little more than a condensing B class ordinary dryer that scores 4,4 kW for the full load (0,55 kW/kg) so the difference is negligible to me.

Anyway, I always iron all the stuff that gets washed unless it is underwear or kitchen rags. It usually takes me 1 to 2 minutes to do a t-shirt or jeans to 10 minutes for a shirt or a complete bed set. That's way faster than using a dryer. I don't know what magic happens in your machine (so please tell me because I hate ironing!) but even when underloading the dryer, cottons are always a little creased and I need to iron them. Even stuff left a little damp. Call me crease-manic if you want but I can't stand them!

@favorit: I love that Candy combo, it has sweet memories as it is the first machine I recall, a neighbor of mine had one (and still has it, working!). I used to call her grandma all the time (she had the age of my grandma indeed) as she often took care of me when my mother was working. I was told once that I had put one of those string curtains in the machine and the old woman didn't notice, so when she went to use the washer she was afraid as she thought that there was a dead animal inside hehehe

 

[toggleswitch2]

~My understanding is that USA dryers use 2.5 kwh to dry one load of laundry. But I need to verify that factoid that was found in Consumer Rerpots magazine.

~I don't know what magic happens in your machine (so please tell me because I hate ironing!)

1-There is a big differeence between a sondenser dryer and a vented one.
2- Slower spin speeds (i.e. as found in tradtional top-loaders) cause less wrinkling.
3- Our dryers are large and use 5,600 watt heaters. Perhaps intense quick heat and a long cool-dpwn period help to de-wrinkle.
4- I give my shirts a quick shake before they go into the dryer. I also "iron" my trousers (especially jeans) with my hands and fold them as if they are going to be placed on a hanger. (Hip folded on top of hip, no creases, crotch out).
It really sounds ridiculous, but it helps. The dryer will only set any crease found in jeans from the washer.

~from huge American-style commercial dryers all the clothes seem to be far more creased for me.

These don't cool-down long enough. The true commercial machines have a heat input 5+ times greater than a home-style machine and will over-dry some parts of the garments/contents before other parts are dry. Another disadvantage of these machines is that they tend to dry near 190*F (88*C). I believe home machines tend to hover between 140*F to 180*F (60*C to 82*C). (American) commericial dryers tend to shrink and fade clothng as well, but hey...they only take 1/2 an hour. *LOL*

Personally I think we all see what we WANT to see in terms of expected results.

 

[toggleswitch2]

Here is a picture of my dryer's timer. The amchine is an 80s to 90s vintage, I believe.

Notice the long "Press Guard" ending to the automatic cycle/programme. This is a selectable option, meaning the machine will terminate after a 10 minute cool-down or it will incorporate this porion of the cycle as well, which I'd say is about one hour in duration.

There are three things in life I won't do. Ironing is one of them. (But I will in an "extreme emergency") *LOL*

 

[toggleswitch2]

Pumping Iron

Well, Ok. Maybe it's not against my religion to iron.
*LOL*

 

[favorit]

Toggles' "no-iron secret" does really work !

quote: "4- I give my shirts a quick shake before they go into the dryer. I also "iron" my trousers (especially jeans) with my hands and fold them as if they are going to be placed on a hanger. (Hip folded on top of hip, no creases, crotch out).
It really sounds ridiculous, but it helps. The dryer will only set any crease found in jeans from the washer"

This works even for line drying.

IMHO even different spinning patterns make differences in wrinkles. A continuous 5 mins-600 rpm spin causes more wrinkles than a pulse spin pattern up to 900 rpm.

Toggles: all our dryers/combos have the cooldown, even that Candy combocrap (570 rpm..) I had.
Many dryers(BSH,Miele,E'lux) even switch to low heat when they sense "damp dry" moisture.
Don't know about "6th sense" Bauknechtpool doing the same

Gabriele, do you really iron even towels coming from the dryer ???

 

[dj-gabriele]

If they are linen towels, yes, I hate wrinkles, if they're standard cotton terrycloth ones, they get folded only (you canìt iron them!) hehe

Toggles, are you sure about that value? I gess it's more like 5,2 kW and not 2,5 otherwise everybody would have USA style dryers

Evaporating 4 litres of water (say 50% moisture remaining in 8kg of laundry) with rise of 70°C in temperature needs some 2.8 kw alone with the usual "rough" calculations

 

[toggleswitch2]

Yes I'm sure. I remember saying to myself AHA, the 5,200 watt heating element is on for about half the time of a one hour cycle, so 2.5 KWH makes sense.

Are you sure the KW value you are speaking of is not the value (measure/intensity/energy) of the heat input rather than kilo-watt hours consumed?

The metric system confuses me. Kilowatts are used to denote not only heat input (where we use BTU/h-- British Thermal Units per Hour) but energy consumed (Kilo-watt hours). In the metric world I have seen kilowatts used to measure heat from a gas burner.

 

[toggleswitch2]

This document uses 2.5 KWH per dryer load for an American vented dryer

If condenser dryers take 4.4 to 4.5 KWH per load it is no wonder that they are considered the devil.

Are you sure, again, that that figure is not the heat input? (I'm sorry I REALLY dont know what tot make of KW as heat inputs figures!

[Another good thing about this site is that *C temperatures are now making sense to me as are metric sizes and dimensions].

How long does a condenser dryer take to dry a typical load?
In the days of top-loaders with 640rpm spins, dryers took one hour. I'd say now, with 1,000+ rpm spins, dryers take about 45 minutes.


http://www.ksre.ksu.edu/library/hous2/GT342.pdf

 

[dj-gabriele]

Toggles:
Yeah, sorry I skipped the kWh thing, I meant an easier writing than in Joules and I ended up with power and not energy! (A really bad mistake for the energy engeneer in me haha!)

The figures I gave you are for a load of 8kg of laundry spun at around 1000/1200 rpm.
But I have yet to see somebody loading a domestic dryer with that much clothing.
I can't tell how long it takes to dry in a standard dryer as we use an industrial 20 kg dryer that does the full load in 30 minutes (usually spun at 3600rpm in the extractor first) as here we have an advantage that my parents own a laundry.
When I once brought there the load (5 kg spun at 400rpm) of our home machine because it started raining and I was leaving the day after, it was done in 15 minutes, cooldown included but as I told that thing is a monster!
My guess is that a standard (4-5 kg load) is done in a little less than 2 hours with a heater with 2kW power

 

[dj-gabriele]

BTW:

It actually is not-legal to use kWh as an energy measure, you're supposed to use only Joules but as electricity is metered that way, many people use it outside the scientific field, confusing power with energy! (Just like I did wihout noticing)

1kWh = 3,6 MJ