Fused spur for tumble drier

[JohnW2]

try a quick google!

Yes, I could and, admittedly, it would takes only a very short period of time to do that.

However, it's interesting how technology has changed some people's approach to 'discussions'. At least traditionally, if I was having a discussion and asked someone something, if they immediately knew the answer, they would simply tell me that answer, rather than suggest I went to look for the answer elsewhere

Kind Regards, John

 

[DetlefSchmitz]

You'

rather than suggest I went to look

You'd learn a lot more in 20 seconds by googling, but since you insist - Yes, there are loads of them.

 

[JohnW2]

You'd learn a lot more in 20 seconds by googling, but since you insist - Yes, there are loads of them.

Thanks. I wasn't criticising or 'getting at' you, but was merely making an (to me 'interesting') observation about how advances in IT had changed the way in which some people answer questions and conduct discussions!

Probably not the least because of 'old age', I'm probably old-fashioned in this respect. If someone asks me a question and I know the answer, I will usually tell them that answer, rather than telling them how they can easily find the answer (maybe 'plus a lot more') for themselves - and that particularly if all I've been asked for is a 'yes/no?' answer.

The world has changed

Kind Regards, John

 

[robinbanks]

Heat pump tumble driers? Sure. It's a shame, in a way, that more things that need relatively low temperatures don't use heat pumps. Heater elements are cheap to buy though..

It does irk me that all my appliances (dishwasher, washer etc) take a cold fill and heat with a heater element, when I have a perfectly good air source heat pump capable of generating water hotter than they need at a third the price they do..

 

[JohnW2]

Heat pump tumble driers? Sure. It's a shame, in a way, that more things that need relatively low temperatures don't use heat pumps. Heater elements are cheap to buy though..

Agreed, and the concept is sound enough - it was simply that (maybe because 'I don't get out enough'!) I was not aware of this being done in any domestic driers. In fact, I would imagine that clothes etc. could probably be dried successfully with just blown ambient temperature air - which would require neither a heating element nor a heat pump.

It does irk me that all my appliances (dishwasher, washer etc) take a cold fill and heat with a heater element, when I have a perfectly good air source heat pump capable of generating water hotter than they need at a third the price they do..

I think that was probably the first reaction of most of us when 'cold fill only' machines started becoming the norm, and it's something which has been discussed at length, here and elsewhere.

I think it's really all down to the distance between your ASHP and your appliances. For people with traditional (stored) hot water systems, and for some of them with combis, there is a very appreciable length (hence volume) of pipework between the source of the hot water and the appliance. For such people (I presume regarded as 'the majority' by appliance manufactures), when the volumes of water utilised by appliances reduced considerably, it was often not much greater (if any) than the volume water (usually cold) contained in that pipework.

That results in a potentially 'double whammy' situation. Firstly, the main consequence of drawing water from the 'hot supply' may be to fill the pipework with heated water - loss of which heat (hence energy/cost of heating it) is 'wasted', at least during Summer months. Secondly, since most (or all) of the 'hot' water drawn into the appliance may actually be cold (or fairly cold), additional energy (hence cost) has to be consumed by the appliance's heating element to bring it up to the desired temperature.

That is the argument which is usually wheeled out, but I've never seen any chapter and verse which confirms that it actually works out like that in practice. However, as I said at the start, the argument/theory obviously depends crucially on the amount of pipework between the source of hot water and the appliance.

Kind Regards, John

 

[robinbanks]

In fact, I would imagine that clothes etc. could probably be dried successfully with just blown ambient temperature air

I don't disagree with you there; moving air contains enough energy to knock water molecules out of clothes (line drying on a windy day doesn't need a high ambient temperature), though in a dryer setting we do generally need some way of dealing with the moisture once it's in the air - either condensing it out or venting it out.. if we're venting it out that's a problem for things like Passivhaus and other well insulated dwellings because the dryer is actively deleterious to the warm envelope of the house unless it's been plumbed to draw from and vent to the world (and the hoses suitably insulated). And if we're condensing it then we need to do something to generate a temperature difference, which is probably a heat pump or compressor

We see heat pump technology cost quite a lot- our HP dryer was about 600 quid, the ASHP about £2.5k.. Yet when one considers the ubiquity and relatively low price of a refrigerator, which is conceptually the same thing/process, but flowing the heat in the opposite direction it seems like heat pumps shouldn't cost so much.

Perhaps they won't one day, when they've achieved a similar ubiquity, but I don't know why the scale of economics fridges benefit from doesn't have more of an impact on HP driven appliances sooner. I can only imagine that there's a bit of marketing/hype surcharging going on

the argument/theory obviously depends crucially on the amount of pipework

That's a great point that I hadn't considered , I think because I couldn't see it; I had the luxury of designing the house I sit in now, and there is a 300L hot water tank sat next to the washer, on the other side of the wall to the sink and dishwasher and immediately underneath the main bathroom all plumbed on the end of about 2m of plastic pipe each. This was a conscious decision focused on making close use of a single waste stack and having short pipe runs so taps came hot quickly

I'd forgotten about my in-laws' place, on the other side of the party wall; designed by them but with not so much attention to this aspect where, literally, the sink and dishwasher are in the north corner, the washer in the east, hot water tank in the south and bathrooms in the west, all plumbed in in copper and the sink takes at least 30 seconds to run warm..

That's about 5L I believe and more than each washing stage consumes..

 

[JohnW2]

I don't disagree with you there; moving air contains enough energy to knock water molecules out of clothes (line drying on a windy day doesn't need a high ambient temperature),....

Indeed. One issue is that cooler air is able to hold much less water vapour, so one would presumably need to shift a lot more cool air than hot air. Whilst, in some senses, that's not a problem, as you go on to say ....

..... though in a dryer setting we do generally need some way of dealing with the moisture once it's in the air - either condensing it out or venting it out.. if we're venting it out that's a problem for things like Passivhaus and other well insulated dwellings because the dryer is actively deleterious to the warm envelope of the house ....

Indeed, but that's qualitatively true whether the air is hot or ambient - the difference, as above, being that if one uses cooler air, one has to lose/'waste' more of the air which is at 'indoor ambient temp'. Mind you, that's only an issue at times of year when the air inside the house is being heated - at other times of the year, it doesn't matter a jot how much of the indoor air gets pumped out.

.... And if we're condensing it then we need to do something to generate a temperature difference, which is probably a heat pump or compressor

True, but condensing isn't the only way of removing water vapour for air - there are plenty of very hygroscopic substances around (even the anhydrous copper sulphate we played with at school). However, unless we threw away the used substance (environmentally bad, and with a cost), one would (assuming the situation was reversible) need energy (hence cost) to heat it to 'recycle' it.

Perhaps they won't one day, when they've achieved a similar ubiquity, but I don't know why the scale of economics fridges benefit from doesn't have more of an impact on HP driven appliances sooner. I can only imagine that there's a bit of marketing/hype surcharging going on

I agree. Heat pumps are, as you say, not conceptually different from (potentially very cheap) fridges and freezers.

That's a great point that I hadn't considered , I think because I couldn't see it; I had the luxury of designing the house I sit in now, and there is a 300L hot water tank sat next to the washer, on the other side of the wall to the sink and dishwasher and immediately underneath the main bathroom all plumbed on the end of about 2m of plastic pipe each. This was a conscious decision focused on making close use of a single waste stack and having short pipe runs so taps came hot quickly

In that case, then 'dual fill' appliances would almost certainly be beneficial for you - but you are problem the 'exception', rather than the rule.

I'd forgotten about my in-laws' place, on the other side of the party wall; designed by them but with not so much attention to this aspect where, literally, the sink and dishwasher are in the north corner, the washer in the east, hot water tank in the south and bathrooms in the west, all plumbed in in copper and the sink takes at least 30 seconds to run warm.. That's about 5L I believe and more than each washing stage consumes..

Same here. At a very rough estimate, there's probably something like 20m of pipework (a mixture of 22mm and 15mm) between our hot water cylinder and the appliances. If one assumes 10m of each size of pipe, that seem to amount to about 5.6 L, similar to your in-laws' house - so definitely very significant with today's 'low volume' appliances.

Kind Regards, John