tumble dryer dehumidifiers

[paulparkie]

Okay, so I have just recently moved into a new appartment - and this means that I can't have my hose vent from my tumble dryer going outside.

I've managed to get my hands on a condenser box, which you just attach the vent pipe to and hey presto it's supposed to collect the water.

However, it dosen't seem to work - now granted I didn't get it from new so I haven't got the instructions, but I've tried adding a bit of cold water in the hope that that will aid the condensing - but that hasn't worked either - I just end up with a very steamy room.

Any suggestions?

[Lurch]

On 4 Jul 2004 08:55:30 -0700, [e-mail] (paulparkie) strung together this:

Throe that useless contraption out of the window and go and buy a proper condenser dryer. If you want it to work that's about your only option.

[Chris Hodges]

I've never used one but:

- They seem to come with ice packs that you put in the freezer overnight before use.

- They're not supposed to be much good.

[Ian Stirling]

At best - the amount of heat released by water condensing is about twice (per kilo) that of ice melting. So, you'r at best going to need double the amount of water you remove from the clothes. To get a "reasonable" result, say 10C output at 100% RH, you are probably looking at an ice pack that will absorb around 4Kw (heat added by dryer and heat that would be needed to heat the air from 10C-room temp).

Say the dryer runs for 1 hour, 4Kwh is around 15MJ, so will melt around

15Kg of ice.

[Chris Hodges]

In fact it's worse than that - at 273K, latent heat of fusion is

3.3x10^5 J/kg, latent heat of vapourisation 2.5x10^6 J/kg.

Also specific heat capacity of liquid water is 4.2x10^3 J/kg/K, of ice

2.1x10^3 J/kg/K.

In more detail, and looking at it slightly differently to you, each kilogramme of water to be condensed and cooled (from say 60 degC) to room temperature (say 20 degC) will release 2.5x10^6 + (4.2x10^3 x 40) =

2668 kJ (assumes condensation happens at 60). If this is removed by heating ice (starting at -15 degC) to 0 degC and then melting it we will absorb 361.5 kJ per kilo. 2668/361.5=7.38

In other words we would need ~7kg of ice per kilo (~litre) of water soaked into the clothes.

[Ian Stirling]

Sounds wrong. Hmm

I think I may have been remembering numbers I was doing for energy absorbtion for a block of ice cooled to around 0K. For this temperature, the number I remembered of around a megajoule/Kg is broadly right. However, few people have a freezer that goes anywhere near 0K.

[BillV]

They don't work. I tried one once and took it back to the shop. The assistant told me that they had almost 100% return rate

[MLeo]

Can anybody recommend a good condenser dryer ?

many thanks M

[Lurch]

On Mon, 5 Jul 2004 22:05:40 +0100, [e-mail] (MLeo) strung together this:

One of the Miele ones, but they're pricey. Bosch are next, then Creda\White Knight. There's some others dotted around in the middle but you should find one of those suitable.

[MLeo]

Thanks

Do you have any views on a good washer/dryer ?

Many Thanks M

[Christian McArdle]

I hadn't realised there was such a thing. If there really was no way I could squeeze two boxes in, I'd use a clothes line.

Christian.

[Christian McArdle]

I've got a Bosch, which is vastly better than any previous one I've used. I prefer it to the Miele too, as the controls are better.

If you can afford it, get a sensor dryer. They are so much less hassle. Just load and press start. They'll probably pay back the extra cost due to reduced energy usage, but I haven't done the sums to be sure.

Christian.