Energy Saving

[Cabinetman]

I installed an insulated hot water circulation ring in our place, as the boiler is quite a way from the kitchen tap. Instant hot water for the small cost of a 5w circulator pump.

That’s interesting, do you have it running all the time or every other five minutes or something? Wouldn’t work with my Combi boiler I shouldn’t think. Seriously thinking of changing next time to a hot water tank again, really fed up with running the tap and wasting all that water whilst the boiler fires up and delivers -eventually – also the future Swmibo hasn’t got into the habit of not running the hot tap for a few seconds, it doesn’t give you any hot water and it eventually beggers up the boiler (According to my Plumber). Ian

 

[hairy]

Interesting about the fridge, I’ve always wondered. Do you not find you get a strange taste to your tea using a flask?
There is a lot on the Internet about not having a plastic kettle – it not being at all good for you (BPA). Leave you to look it up. Ian

It would be sacrilege to put tea in a flask obviously! Stick to just hot water then make cuppa soup, tea, hot chocolate whatever in the mug.
That particular flask keeps the water so hot it seems no different to just boiled from the kettle. Brodies do Earl Grey in a pocket friendly sachet if out and about, then I don't need milk.

 

[hairy]

Obviously every tap is different but, I experimented with one hot water tap in our house that took ages to warm. I measured 7 pints before the flowing water changed from cold to warm. That means every time the hot tap was turned off 7 pints of hot water was left in the pipes to cool off. Wasted heat!

Also, when I was young and impressionable, my BIL (an Englishman, and therefore a tea expert) taught me to always use cold water to fill the jug as it effects the taste.

Cheers, Vann.

We bought a dishwasher in a previous house because running the tap to get hot water wasted more water than a dishwasher used in the entirety of a full cycle! More than 20 litres IIRC! Some mad plumbing going on there.

 

[dannyr]

double-walled kettles - anyone use these?

Should be able to do one boil for the morning's tea

 

[Sporky McGuffin]

On the money-saving-and-tea combo front, has anyone considered wearing PVC trousers with wellies, and putting a teabag under each foot, then going for a long run?

 

[MarkAW]

ANY THOUGHTS / COMMENTS ON MY FINDINGS

Yeah, you have too much time on your hands

 

[nickds1]

Probably because not everyone has a hot water system that is classed as potable, many used to have open header tanks in the loft that would contain dust and dead insects, etc etc and if you have ever replaced one of these you often found there is a lot of sludge at the bottom.

I realise that - which is why I mentioned the GSHP - the hot water we get from that is potable and sterilised weekly (2-hour heated > 60C) and there is no header tank - ours is a pressurised sealed system.

Older properties with vented HW systems are indeed ghastly.

Obviously every tap is different but, I experimented with one hot water tap in our house that took ages to warm. I measured 7 pints before the flowing water changed from cold to warm. That means every time the hot tap was turned off 7 pints of hot water was left in the pipes to cool off. Wasted heat!

We have a circulating HW system as it's a large property - there is no cold water run-out from the hot tap - it's hot pretty much instantly. Again, older and smaller properties are unlikely to have this.

But if you can, filling the kettle with potable hot water saves more energy...

 

[Krome10]

The below graph from the great courses plus shows it is fairly linear in terms of energy needed to rise in temp until you get to boiling point and then it is an exponential jump to get a change of state phase

View attachment 120614

Well, that's two things I've learnt today, the other being that you can heat water above 100c. Didn't realise that!! That's for posting the graph.

As for saving heat from hot water that goes down the drain, as @hairy points out, there's the issue of condensation. Does that not bother people? Guess it depends what kind of set up you have for heat and ventilation...

 

[D_W]

We bought a dishwasher in a previous house because running the tap to get hot water wasted more water than a dishwasher used in the entirety of a full cycle! More than 20 litres IIRC! Some mad plumbing going on there.

the dishwasher can be bettered, but it takes sort of the old time soak and then quick wash and rinse method. And it's probably a difference of a gallon.

I am very stingy, and that makes me passively eco. But I cannot convince my spouse to line dry or skip the drying cycle on the dishwasher. Many of the articles expounding on the efficiency of dishwashers forget to mention the long needless heated dry and they compare the dishwasher to someone allowing the water to run continuously for 20 minutes.

The other benefit of hand washing, if one actually adheres to it, is the racks and shelves are rarely short of cups and spoons.

 

[Spectric]

Well, that's two things I've learnt today, the other being that you can heat water above 100c.

The water in your car cooling system can exceed 100 °C because it is pressurised, thats why if you just release the cap you get a blast of steam because water cannot exist above 100 °C at atmospheric pressure, so releasing the cap releases the pressure and that water almost instantly changes state into steam.

 

[Just4Fun]

I installed an insulated hot water circulation ring in our place, as the boiler is quite a way from the kitchen tap. Instant hot water for the small cost of a 5w circulator pump.

I did this but used a heating circulation pump. I have had 2 or 3 of these fail. How long has your pump lasted? Do you have a link to the type of pump you use?

 

[D_W]

double-walled kettles - anyone use these?

Should be able to do one boil for the morning's tea

yessir, but it's the pot of coffee here that it's keeping hot. Hard to live without once you've used one as the coffee is hot for at least 6 hours and it never gets cooked on a burner (so it actually tastes fresh all day).

 

[Stevekane]

Going back to the water temp at startup,,my son uses electric showers for hairwashing sinks in his hairdressers, in the winter he has to switch to the higher power setting ( not the water flow) to get the correct temp because the mains water temp is that much lower, I suppose the temp difference is exaggerated in a situation where the water is just passing over a heating element.
steve.

 

[John Brown]

I realise that - which is why I mentioned the GSHP - the hot water we get from that is potable and sterilised weekly (2-hour heated > 60C) and there is no header tank - ours is a pressurised sealed system.

Older properties with vented HW systems are indeed ghastly.



We have a circulating HW system as it's a large property - there is no cold water run-out from the hot tap - it's hot pretty much instantly. Again, older and smaller properties are unlikely to have this.

But if you can, filling the kettle with potable hot water saves more energy...

How does it save energy? You're still preheating it with energy.

 

[Fitzroy]

The water in your car cooling system can exceed 100 °C because it is pressurised, thats why if you just release the cap you get a blast of steam because water cannot exist above 100 °C at atmospheric pressure, so releasing the cap releases the pressure and that water almost instantly changes state into steam.

Interestingly water can exist in the liquid state at atmospheric pressure above 100Celcius. It can also exist below 0 Celsius. Both boiling and freezing require nucleation sites for the process to begin. In either ultra pure water or water that has already been boiled these are missing so it can be heated or cooled (under the correct conditions) to above or below the boiling/ freezing points. However, it is not a stable condition and upon disturbing it will instantly freeze/boil.

It’s actually one of the risks of reheating tea in a microwave.

Fitz.

 

[nickds1]

How does it save energy? You're still preheating it with energy.

Perhaps it would have been better to say "save more polluting energy" as obviously the same number of joules are required to boil a given amount of water regardless of how those joules are produced. However in our case a chunk of those joules are solar and produced by a GSHP with a COP of around 3.5 and "green electricity" driving that.

 

[Trainee neophyte]

I've decided that the concept of a dishwasher as a home appliance is a complete fabrication. There is no such thing. Firstly I don't have any dishes in my house - plates, bowls, saucepans etc, but no dishes. This may just be an accident of geography, but annoying none the less. Why isn't it a plate washer?

Then there is the whole idea of actually "washing" the plates: they need rinsing before you put them in, then they more often than not need scraping and scouring to remove the baked on crud afterwards. Does all this extra water and energy get added to the balance when they decide how much water a dishwasher uses? I think not.

The only thing it does do, even on a quick 35°C wash, is steam/bake everything afterwards. It ought to be called a plate steamer, as that's about the only job it manages competently.

 

[Chris152]

If it's tea you're making, this might be useful (from The perfect water temperature for brewing tea | Tealovers.com )

General Guidelines
Manufacturers will usually provide temperature guidelines for you to follow but if these are not available the following general guidelines can be used:
Pu’er teas: 200° to 212°F (93°to 100°C)
Black teas: 190° to 200° Fahrenheit (88° to 93°Celsuis)
Oolong teas: 180° to 200°F (82°to 93°C)
Yellow teas: 175°F (79°C)
White teas: 160° to 185°F (71° to 85°C)
Green teas: 140° to 190° F (60° to 88° C)

What's more:
"When the water starts bubbling furiously and great volumes of steam are rising, the water is no longer suitable for making tea. Using boiling water can make the tea bitter. You may not notice this if you are using cheap industrial tea where the subtle leaf flavors are not noticed but it will be evident with a better tea."

Plus, if it's boiling away like that (if memory of o-level physics serves me) you're wasting energy converting water at 100C to vapour (latent heat of vaporization). This has stuck in my head for decades, and I've always tried to manually switch off the kettle just before it starts to vaporize - I'm quite sure I've saved a fortune and already done my bit to prevent glbal warming.

So if you're boiling the water in your kettle to make tea (or coffee) you're already wasting energy and, worst of all, spoiling your tea.

 

[Sporky McGuffin]

Then there is the whole idea of actually "washing" the plates: they need rinsing before you put them in,

New dishwashers (last ten years' worth at least) do a better job if you don't rinse first.

 

[hairy]

As for saving heat from hot water that goes down the drain, as @hairy points out, there's the issue of condensation. Does that not bother people? Guess it depends what kind of set up you have for heat and ventilation...

Opening the window fixes that