Scrutable

Nickynockynoonoo wrote: ↑

Fri Sep 02, 2022 10:37 am

Opti wrote: ↑

Thu Sep 01, 2022 12:38 pm

Even better idea: Spend about £300 on an induction hob and boil a cupful in a saucepan. Easy!

When we first got our induction hob we raced it against our kettle. Both with 1L water. The large ring on boost is 3kW so is our kettle. Guess what? They both boiled at exactly the same time. I'd say our kettle is pretty efficient.

Because ultimately it takes 4.2 kJ/kgK to heat water, plus losses in heating up the containers and the heating system, and what escapes on the way. That an electric kettle is similar to an induction hob isn't such a surprise.

The only way you can beat that 4.2 kJ/kgK is use a heat pump. But heat pumps struggle to heat water more than about 50-60C, and I'm not aware of ones designed for cooking-sized quantities.

insignificant wrote: ↑

Fri Sep 02, 2022 2:18 pm

... I've been filling my tea or coffee cups with water > pour in to kettle > boil ever since I got a kettle with a concealed element ...

I thought I was the only one. 2 cups if we're both having one.

Also, living somewhere drought is a constant threat, any waste water from rinsing etc. goes in a bowl then on the plants.

IvanV wrote: ↑

Fri Sep 02, 2022 2:23 pm

Nickynockynoonoo wrote: ↑

Fri Sep 02, 2022 10:37 am

Opti wrote: ↑

Thu Sep 01, 2022 12:38 pm

Even better idea: Spend about £300 on an induction hob and boil a cupful in a saucepan. Easy!

When we first got our induction hob we raced it against our kettle. Both with 1L water. The large ring on boost is 3kW so is our kettle. Guess what? They both boiled at exactly the same time. I'd say our kettle is pretty efficient.

Because ultimately it takes 4.2 kJ/kgK to heat water, plus losses in heating up the containers and the heating system, and what escapes on the way. That an electric kettle is similar to an induction hob isn't such a surprise.

The only way you can beat that 4.2 kJ/kgK is use a heat pump. But heat pumps struggle to heat water more than about 50-60C, and I'm not aware of ones designed for cooking-sized quantities.

There's a small benefit from using water that's been sitting at room temperature rather than water that is cold from tap - 20C start vs ~10C starting temperature (seasonally dependent).

A potable water heat pump that produced 50C water could maybe save some amount of energy - both for tea and cooking.

insignificant wrote: ↑

Fri Sep 02, 2022 2:18 pm

The energy saving is probably trivial, but I've been filling my tea or coffee cups with water > pour in to kettle > boil ever since I got a kettle with a concealed element (RH Buckingham quiet boil)

People I live with always fill the kettle from the tap and boil more water than they need to

I do exactly the same. It’s one of my bete noirs when people fill up the kettle to the brim to make a single cup. It’s also faster.

Ignore

Gfamily wrote: ↑

Fri Sep 02, 2022 9:21 pm

Lol, we should have a thread for bêtes noire (like putting the plural in the wrong place).

Or even bêtes noires (like adjectives that don't agree with their nouns).

bolo wrote: ↑

Fri Sep 02, 2022 9:22 pm

Gfamily wrote: ↑

Fri Sep 02, 2022 9:21 pm

Lol, we should have a thread for bêtes noire (like putting the plural in the wrong place).

Or even bêtes noires (like adjectives that don't agree with their nouns).

Hoist by my own pedant.

When you say:

IvanV wrote: ↑

Fri Sep 02, 2022 2:23 pm

The only way you can beat that 4.2 kJ/kgK is use a heat pump.

I hope you're not suggesting that heat pumps can change the specific heat capacity of water!

I'm posting this with some hesitation because I can clearly see what a hard time my UK friends are having right now and it's only set to get much worse.

I have just had my electricity bill for August, the second most expensive month here (February is generally the highest). It's an all-electric house and as it has been so farking hot this year I have had to run aircon in one room more than I would normally, mostly though it has been a fan on just about all day with the doors open. Sometimes 2 rooms. Had the ceiling fan on in the bedroom for about 7 hours a night. Kitchen use has been the same as ever.

My bill? €113, some 10% up on last year. What the f.ck is going on in the UK that makes the situation so drastically at odds with the rest of Western Europe? I understand that there is government action being taken here to protect consumers that will have to be accounted for in the future, but it just seems so wildly different.

In related news, there are a lot of much loved music venues about to throw in the towel because huge electricity costs despite costed plans to avoid this being presented to the government by trade associations. Apparently the Culture Secretary is the major stumbling block.

Sorry.

Opti wrote: ↑

Sat Sep 03, 2022 9:39 am

My bill? €113, some 10% up on last year. What the f.ck is going on in the UK that makes the situation so drastically at odds with the rest of Western Europe? I understand that there is government action being taken here to protect consumers that will have to be accounted for in the future, but it just seems so wildly different.

Spain and Portugal are the exceptions in Western Europe, rather than the UK. The EU gave them an exemption from state aid rules in energy markets which allows them to keep consumer prices lower.

WFJ wrote: ↑

Sat Sep 03, 2022 9:47 am

Spain and Portugal are the exceptions in Western Europe, rather than the UK. The EU gave them an exemption from state aid rules in energy markets which allows them to keep consumer prices lower.

Ah, thanks for that. I know quite a few fortunate homeowners in the UK who are going to be shutting up their houses in the UK for 3 months over the winter and renting one of the many holiday lets available here off-season in order to save quite a bit of money.

edit: What about France? Their bills are similarly low.

Opti wrote: ↑

Sat Sep 03, 2022 9:57 am

WFJ wrote: ↑

Sat Sep 03, 2022 9:47 am

Spain and Portugal are the exceptions in Western Europe, rather than the UK. The EU gave them an exemption from state aid rules in energy markets which allows them to keep consumer prices lower.

Ah, thanks for that. I know quite a few fortunate homeowners in the UK who are going to be shutting up their houses in the UK for 3 months over the winter and renting one of the many holiday lets available here off-season in order to save quite a bit of money.

edit: What about France? Their bills are similarly low.

I don't know about France specifically. The EU has been discussing decoupling their gas and electricity markets to prevent sharp rises in electricity in the coming months. This is what has already happened in Spain and Portugal, as I understand it.

In Germany my electricity cost hasn't actually increased since the yearly increase in February, but it will. The wholesale price has risen sharply and this will be passed on to consumers.

WFJ wrote: ↑

Sat Sep 03, 2022 10:21 am

Opti wrote: ↑

Sat Sep 03, 2022 9:57 am

WFJ wrote: ↑

Sat Sep 03, 2022 9:47 am

Spain and Portugal are the exceptions in Western Europe, rather than the UK. The EU gave them an exemption from state aid rules in energy markets which allows them to keep consumer prices lower.

Ah, thanks for that. I know quite a few fortunate homeowners in the UK who are going to be shutting up their houses in the UK for 3 months over the winter and renting one of the many holiday lets available here off-season in order to save quite a bit of money.

edit: What about France? Their bills are similarly low.

I don't know about France specifically. The EU has been discussing decoupling their gas and electricity markets to prevent sharp rises in electricity in the coming months. This is what has already happened in Spain and Portugal, as I understand it.

In Germany my electricity cost hasn't actually increased since the yearly increase in February, but it will. The wholesale price has risen sharply and this will be passed on to consumers.

In France the electricity price rise has been capped at 4% https://www.politico.eu/article/frances ... ouseholds/ (even though their nuclear plants have been struggling to run at full capacity at times, due to the heatwave and drought impacting the cooling mechanisms).

UK is unusually gas-dependent for generating electricity. About 40% gas, compared with e.g. about 12% for Germany. Despite having the best wind resources in Europe, solar relatively underutilised, a fair bit of hydro potential (habitat-loss concerns notwithstanding) etc etc.

A possible brexit benefit would be the ability to reform the country's energy market independently of what the EU does, due to the country's rather unique situation. But like most such potential benefits it's predicated on the country not being run by evil clowns.

Opti wrote: ↑

Sat Sep 03, 2022 9:57 am

edit: What about France? Their bills are similarly low.

69% nuclear's likely to help.

Opti wrote: ↑

Sat Sep 03, 2022 9:39 am

In related news, there are a lot of much loved music venues about to throw in the towel because huge electricity costs despite costed plans to avoid this being presented to the government by trade associations. Apparently the Culture Secretary is the major stumbling block.

Sorry.

Yeah, the landlord of my local MVT-supported place just tweeted

One more f.cking kettle joke about the livelihood of myself, my team and, frankly the only cultural icon left in a once great city, and I will probably start punching people.

They only just scraped through the pandemic (and had much better anti-covid rules than the govt. requires), and now this.

EACLucifer wrote: ↑

Sat Sep 03, 2022 11:00 am

Opti wrote: ↑

Sat Sep 03, 2022 9:57 am

edit: What about France? Their bills are similarly low.

69% nuclear's likely to help.

Although that's currently about 45% nuclear due to drought.

dyqik wrote: ↑

Sat Sep 03, 2022 12:28 pm

EACLucifer wrote: ↑

Sat Sep 03, 2022 11:00 am

Opti wrote: ↑

Sat Sep 03, 2022 9:57 am

edit: What about France? Their bills are similarly low.

69% nuclear's likely to help.

Although that's currently about 45% nuclear due to drought.

True, but the big worry about an energy crunch is for the coming winter, at which point the rivers will have picked up a bit and the reactors will be able to run nearer capacity again.

Martin_B wrote: ↑

Sat Sep 03, 2022 1:49 am

When you say:

IvanV wrote: ↑

Fri Sep 02, 2022 2:23 pm

The only way you can beat that 4.2 kJ/kgK is use a heat pump.

I hope you're not suggesting that heat pumps can change the specific heat capacity of water!

I'm sure you know what I meant is, use less electricity/gas than 4.2 kJ/kgK to heat water.

Opti wrote: ↑

Sat Sep 03, 2022 9:39 am

My bill? €113, some 10% up on last year. What the f.ck is going on in the UK that makes the situation so drastically at odds with the rest of Western Europe?

What's this per kWh? The UK price is currently 28p, rising to 54p on October 1st.

The obvious country to compare with the UK is Ireland - also an island at the west of Europe. There the price seems to be about 30c if I understand this correctly: https://www.bonkers.ie/compare-gas-elec ... r-results/ Apparently, Ireland currently generates over 50% of its electricity from gas. Apparently, there are so many data centres in Ireland that their backup diesel generators could make a significant difference to supply - https://businessplus.ie/news/energy-crisis-ireland/ If the electricity price rises sufficiently I expect it would be good business not just to use them to take data centres off the grid, but to run them feeding excess power into the grid (though they are presumably only intended as short-term backups so might not do so well run for months at a time.

By chance, I also hit upon this article: https://businessplus.ie/news/energy-crisis-ireland/ from 2015 which says:

Any conflict or dispute involving Russia or a big producer in the Middle East could have serious consequences for Ireland.

which was a pretty accurate prediction.

IvanV wrote: ↑

Sat Sep 03, 2022 4:57 pm

Martin_B wrote: ↑

Sat Sep 03, 2022 1:49 am

When you say:

IvanV wrote: ↑

Fri Sep 02, 2022 2:23 pm

The only way you can beat that 4.2 kJ/kgK is use a heat pump.

I hope you're not suggesting that heat pumps can change the specific heat capacity of water!

I'm sure you know what I meant is, use less electricity/gas than 4.2 kJ/kgK to heat water.

I think you mean that a heat pump allows you to use less electricity because it allows you to start from a higher temperature. The specific heat capacity of water doesn't change (well, it does very slightly) but it's the amount of 'K' you have to change rather than reducing the '4.2' bit.

Martin_B wrote: ↑

Sun Sep 04, 2022 5:11 am

IvanV wrote: ↑

Sat Sep 03, 2022 4:57 pm

Martin_B wrote: ↑

Sat Sep 03, 2022 1:49 am

When you say:

I hope you're not suggesting that heat pumps can change the specific heat capacity of water!

I'm sure you know what I meant is, use less electricity/gas than 4.2 kJ/kgK to heat water.

I think you mean that a heat pump allows you to use less electricity because it allows you to start from a higher temperature. The specific heat capacity of water doesn't change (well, it does very slightly) but it's the amount of 'K' you have to change rather than reducing the '4.2' bit.

No, he means that a heat pump allows you to use less electricity because some of the energy comes from the external source of heat, so the amount of J you have to put in is reduced from the 4.2/K you'd otherwise have to put in.

Millennie Al wrote: ↑

Sun Sep 04, 2022 12:49 am

Opti wrote: ↑

Sat Sep 03, 2022 9:39 am

My bill? €113, some 10% up on last year. What the f.ck is going on in the UK that makes the situation so drastically at odds with the rest of Western Europe?

What's this per kWh? The UK price is currently 28p, rising to 54p on October 1st.

That's not a trivial question to answer here in Spain.

The kWh rate I am contracted to varies not only daily but by time of day. A persons individual rate is also affected by the total potencia you are contracted for. My expensive hours are between 10.00hrs- 14.00hrs and 18.00hrs- 22.00hrs. A mid-rate is between 08.00hrs- 10.00hrs and 14.00hrs- 18.00hrs. Cheapest rate is 00.00hrs- 08.00hrs. and at weekends/National holidays. It is remarkably cheaper in the lower rate hours.
By using high drain appliances (washing machine, dishwasher etc.) during the cheap hours there are massive savings to be made. You just have to be a bit organised. Most people here eat late and stay up late so a lot of cooking goes on after 22.00.

I'm very pleased to have kept my bill within touching distance of last years bill considering how damn hot it has been here since late June.

Gfamily wrote: ↑

Fri Sep 02, 2022 11:17 am

I thought I read somewhere that using a microwave is more efficient than using an electric kettle

I tend to doubt that.

The electric kettle just makes its bottom plate hot with simple electrical resistance. There's not much more to it than that so other than the heat capacity of the base itself absorbing some energy, the rest of the energy makes the water hot. Microwaves have an inefficiency in converting electrical power into microwaves, which similarly makes the magnetron hot, but that's cooled by a fan, deliberately throwing energy away.

I can't remember what sort of efficiency they're expected to have. Time for an experiment.

<edit to add> It occurs to me that even if it's less efficient, microwaving a mug of water could easily be more efficient than boiling more than you need in a kettle.

PBS did it. For boiling an equal amount of water:

Inside Energy spoke with Tom Williams, a researcher at the National Renewable Energy Lab, to break down the rough efficiencies:

A microwave is about 50 percent efficient. Most of the energy is lost in the process of converting electricity to microwaves (which are part of the electromagnetic spectrum).
An electric stovetop is about 70 percent efficient, although that varies widely depending on the type of pot or kettle you use. Most of the energy is lost heating the air around the stove.
An electric teakettle is about 80 percent efficient, although again this varies from kettle to kettle. Electric kettles are generally very well insulated, and the heating coils sit directly in the water, so less heat is lost to the air.
An induction stove or hot plate is about 85 percent efficient. It creates an electromagnetic current directly in a pot to generate heat, losing very little to the air.

They confirm Martin's point that microwaving a mug of water is better than boiling far too much in a kettle, in case anyone was profligate/feckless enough not to realise that. Douze points, Martin.

http://rmpbs.lunchbox.pbs.org/blogs/new ... oil-water/