Wednesday, 11 May 2016

Check my physics here...

As we have already seen there are moves afoot in Europe to reduce the power of various household appliances.

Update: See comments below - as this sounds like bad media reporting.

We have seen this in tumble dryers already, and there is a report (here) on kettles, toasters, and hair dryers.

Now, I am not going to debate the whole climate change thing! It makes a lot of sense for things to be more efficient in what they do, and save energy. I agree with that!

My problem is that some things are generating heat as what they do, and that is pretty much 100% efficient from electricity. There are tricks to do more, such as air-con, which is clever, but that does not help when talking about a toaster or hair dryer or kettle generally.

A kettle is a perfect example - an amount of energy is needed to raise the temperature of a quantity of water from room temperature (e.g. 20℃) to boiling (e.g. 100℃). There are some issues with heat loss from the container in to the environment, but the main factor, as I understand it, is the energy to heat the water.

You can heat the water quickly or slowly. If quickly you have a "high power" device, which is what they want to ban. If you heat it slowly you do not actually save any energy at all, you just take more time and cause more annoyance for the user.

Now, I am sure that there are some things where the power usage is not purely on heat and as such it may do a similar job with less energy - making something more efficient. But some things, like toasters, kettles, hair dryers, tumble dryers, and the like, are there to impart energy as heat. That is their job. That is what they do!

How exactly do any of these initiatives save energy in any way?

It is always worth remembering that people will be people so there is a side effect of such changes. In my house we have seen this happen. We used to have a US style tumble dryer - high power. When it finally broke we tried to get a new one and could not - all were much lower power because of EU rules. It was annoying. So, the simple solution, we purchased a "commercial" tumble dryer instead. It was not much more expensive. It needed a 30A feed which was not that hard to arrange, and is way more powerful than we had before.

So the EU initiatives have resulted in us buying a way more powerful device.

The same will happen with kettles and toasters if they are limited by EU directives.

At the end of the day, the energy we use depends on efficiency of devices, and more modern devices tend to be more efficient. Yes, save energy, but why try and save power on devices whose job is to impart energy - that makes no sense at all.

P.S. Simple example, room temperature 20℃, heating element 21℃, next to bread to make toast. Will the bread turn in to toast? No. It may turn in to stale bread given long enough, and use energy doing it. Clearly at this extreme of "low power toasting" nothing happens.

17 comments:

  1. Assuming it's like the vacuum cleaner and the tumble drier initiatives, I see no problem.

    The power "limit" is not a power limit in the sense you're thinking of - it's a power per unit time limit. Thus, you can have a 3 kW tumble drier as long as it dries clothes 6 times faster than a 500 W unit on a standard test. Same applies with vacuum cleaners - as long as it's sufficiently faster on a set of standard cleaning tests, you can have as much power as you like.

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    1. Not the way it is portrayed by the media - seems to be power limit not efficiency limit.

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    2. Well that's just the media being instinctively anti-EU, isn't it? (I know I was worried about the vacuum cleaner thing, but I had to buy a new one, and, y'know, it's *better* than the higher-power one it replaced. More suction...)

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  2. The media has a long track record of being deceptive. Part of the issue here is that an efficiency limit translates to a power limit for traditional designs - look up Bosch's and Dyson's submissions on the vacuum cleaner limit for some very clear examples.

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    1. Happy to be wrong - if it is efficiency not power - but end result is same - get commercial kits that "just works".

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    2. Note that commercial kit is already under efficiency requirements - so pushing you off a 3 kW "domestic" unit onto a 10 kW "commercial" unit meets the objective of pushing you onto efficient kit :)

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  3. Odd, I couldn't find anything on the proposed limits for Kettles. The documents are meant to be here: http://www.ecodesign-wp3.eu/documents, but it seems the 'Task 3' document that actually contains it is missing...

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  4. I would say here that the Telegraph are on a quest for readers. They literally state "The EU is poised to ban high-powered appliances such as kettles, toasters, hair-dryers within months...". The way it's worded indicates that all of these appliances are being banned, as they are all high powered.

    Regarding efficiency though, there are changes that can be made to 'direct' the heat more efficiently. As an example, we've recently purchased one of these single cup hot water boilers. It's ludicrously high powered for a home kettle (3kw) but also more efficient than the rest of them, as it literally just boils one cup-full at a time (which makes it interesting if you want to fill a pan up!). I would imagine there are similar changes that can be made for toasters, hair dryers etc.

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  5. One genuine source of inefficiency in kettles is 'overboiling', where the kettle is slow to switch off once the water starts to boil - maybe that will be regulated?

    The decade or so of hideous (expensive, unreliably, dingy) CFL lighting thrust upon us by our betters, from which we are just only now stumbling onto the LED-lit uplands has done terrible damage to any argument that these regs are always well thought-out and give us better products.

    Personally I think that energy prices should just be rigged (they already are, after all) to give people an incentive to save money on energy, and then let them decide how to do that or if they'd rather not bother.

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    1. Most of my house has been lit by CFLs since the early 1990s. They work fine when you buy the right ones with a high enough wattage for the room you are trying to light. My dad has just replaced some 8 year old CFLs with LED lights, and 25% of the LEDs have failed in under 3 months so some of the old CFLs have gone back in. On top of that, LED lights are only about twice as efficient as CFLs.

      One notable failure was GU10 CFLs, they're just too small to sensibly compact a flourescent tube into. I resolved ths problem by not fitting any GU10s in my house, but a lot of people did fit them because they're cool and trendy and interior design "consultants" said they look good. Sigh.

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    2. I've been pretty happy with the GU10 LED lights I got off Amazon 3-4 years ago. But it has to be said that if you want decent ones you seem to need to buy them online - the stuff that the likes of Tesco sell is rubbish (or at least it was the last time I needed some LED lights)

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  6. I haven't read the latest report, but the last time (2014?) the papers reported that the EU were going to limit the power of kettles, toasters, etc. I did actually bother to read the whole report and it said no such thing.

    The 2014 report was actually very sensible - they were interested in stuff like saving energy by making the auto-cutoff on kettles faster acting, making it easier to fill the kettle with the exact quantity of water needed rather than heating too much, etc.

    The thing the 2014 report focussed mostly on was the longevity of products - they recognised that modern products are designed to be thrown away after a few years (either because they are poorly made, designed to break or simply promoted in a way that causes people to replace them unnecessarily frequently). Obviously manufacturing a new product costs a lot of energy and there is an environmental impact in disposing of the old one. They wanted to increase the longevity of products and improve their recyclability when they are eventually thrown out. This included phone chargers, which everyone usually has far too many of since they often outlast the phone itself.

    Suffice to say that I found absolutely nothing in the 2014 report to support the media's assertions that Europe was banning high power devices. On the whole, the report looked very sensible and good for both the environment and the consumers. I've not read the latest one, but when I saw the headlines I expected pretty much the same misinterpretation by the media, presumably as a way of turning yet more people against the EU prior to the referendum.

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    1. Thank you, sounds like media getting it wrong again then.

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    2. Yes it's a euro myth:
      http://blogs.ec.europa.eu/ECintheUK/ec-has-not-decided-to-regulate-toasters-and-kettles-and-could-not-decide-alone-anyway/

      In fact, most of what the newspapers write about Europe is made up. Here's the British newspaper Euro Myths A-Z!
      http://blogs.ec.europa.eu/ECintheUK/euromyths-a-z-index/

      Yep... on pretty much every subject, the newspapers have printed made up anti-EU rubbish.

      The vacuum cleaner thing is explained here. It's a good thing that means we get better vacuums that cost less to run. The collective energy saving is enough to power 20 London Undergrounds!
      http://blogs.ec.europa.eu/ECintheUK/tidying-up-the-facts-on-eu-vacuum-cleaner-rules/

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  7. Efficiency in heating is a big deal and easily underestimated by the layman. It's all very well to make _something_ hot, but you generally want to achieve a much more specific goal than just making anything, anywhere, hot.

    A toaster that uses twice as much electricity and fills the room with warm air but doesn't cook bread into toast any faster is actually _less efficient_ even though its manufacturer might describe it as "more powerful".

    Have you looked at how a steam train works versus how a steam boat works? It's fascinating. Steam trains pull their own coal fairly easily on wheels behind them and must stop every few hours at which point more coal can be loaded as necessary. But steam boats have to haul their coal on the space-constrained boat with them thereby reducing cargo space for the whole voyage and they spend long periods at sea. So, steam trains are simple, and inefficient, using a lot of coal to get not much work done and their operators didn't care. Steam boats used compound engines with multiple-expansion, using less coal to get the same work done because for them efficiency actually mattered and was worth the added complexity.

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  8. Steam locomotives certainly did care about efficiency (and many Continental designs used multiple-expansion), they just had to operate under a different set of constraints.

    A locomotive with a given grate area can only burn so much coal in an hour; you want to get as much done with that coal as possible, and increasing the grate area increases the weight and cost of the locomotive (especially since you'll tend to want a larger boiler). A human stoker can only shovel so much coal in an hour (and British locomotives never used mechanical stokers); again, that's a hard limit which can only be improved upon by getting more work done per input coal. And coal is by no means free - not even at the pit, and a significant proportion of a steam railway's effort is spent in moving coal to where it is needed.

    The Big Four and BR constantly experimented to measure and improve work done per input coal, as did foreign designers like Chapelon, Porta, and Wardale.

    The difference is that, within reason, to add weight and size to a steamship's engine to improve efficiency is easy. To add it to a locomotive is hard; later locomotives are already as wide and as tall as the loading gauge will permit and extra length adds the complications of articulation.

    Furthermore the locomotive's weight is a significant proportion of the weight of the train - and trains, unlike ships, go up hills and accelerate their mass to high speeds. There's a point of diminishing returns.

    You get triple-expansion engines on ships and not on (most) locomotives because of these different space and mass constraints, not because free coal fell out of the sky into locomotive tenders.

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  9. I was involved in an energy efficiency facts and myths type talk and we done a demo of otherwise identical 2kW and 3kW kettle's. The 2kW used less power and more energy (think of a delta-t line between water and air with respect to time. The slope will always be the same but longer time means more losses). So less powerful kettle means more energy at the plug. Does mean easier life on the national grid though and lower I2R losses. Not worked out if the lower losses of lower powered kettle make up for its increased energy usage!

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