Has electric demand gone up or down over the years?

[JohnW2]

Equipment may use less power now however surely there are more of use using it? Our population is rising, making more people using.

In terms of total power usage, that's obviously a factor, but probably a fairly small one - although it's an issue that seems to generate a lot of interest, the UK population has actually only increased by about 18% in the past 50 years (around 0.33% per year).

However, as I understand it, the discussion that eric started was really about changes in electricity consumption per dwelling (or per person), rather than total national consumption.

Kind Regards, John

 

[JohnW2]

You say "Exactly", but what BAS suggested is the opposite of what you had written

That's probably (IMO) why he put at the end.

Possibly! Mind you, it'd far from a simple situation, and crucially depends on the supply/demand situation. If supply is limited, then an increase in demand which outstrips current supply can, and does, result in a rise in price.

Kind Regards, John

 

[JohnW2]

So TV used less than 750 watts out of interest I tried different heater voltages 12 volt = 712 watt and 50 volt = 590 watt or 100 volt = 437 watt nothing as low as 200 watt.

I don't pretend to fully understand what you've calculated, but ...

... a typical valve TV would have had about 10 valves with their heaters arranged in series as a '300mA 'heater chain'. Most of the heaters would have been 6.3V (at 300mA), but three or four would have often been 15V ('PL' ones) - so that's something like 90V - 100V total across all the heaters, hence leaving about 145V (240V-95V) across the dropper. The dropper would therefore have to be about 483 Ω and would dissipate about 43.5W. In terms of a 240V appliance (iron or whatever), that resistance would correspond to about a 119W (at 240V) appliance .... unless I've got my sums wrong.

Of course, in reality a 119W (at 240V) appliance would have an appreciably lower resistance than 483Ω when supplied with only 145V (because of lower temperature than at 240V), so the actual appliance needed would have to be rated appreciably less than 119W (at 240V).

Kind Regards, John

 

[ericmark]

Exact figures hardly matter the point was using a voltage dropper was extremely wasteful when compared with a transformer or switched mode power supply.

All around my house the power has dropped except for the washing machine. I fail to understand why but hot and cold fill types have gone. Which is a real pain when water is heated with gas or solid fuel.

Even the computers use less power in real terms. My wife uses her phone and I use a lap top. Back in 1994 we had 4 Amiga computers running with uprated power supplies around 180 W two switched on all day running packet radio with two 2 meter radios and liner amps which have now all been replaced with the internet.

As to how much power was needed for my son to send me a picture using 7plus from Flintshire to Suffolk I dead to think. It often took 24 hours to send one picture. And that would mean loads of BBS's relaying the picture across the country. We ran at a baud rate of 1200 today we would not dream of sending things so slow. On HF it was 300 baud can you think of that not that much faster than Morse.

OK people still do similar today I was looking at a friends power supply to power a 2kW liner to bounce signals off the moon but today he can use skype to talk to other guy to see how it's all going at the time I was doing it skype did not exist.

Radios using 400W were common although the distance using SSB was far improved to when we used AM. Today earth moon earth is using electronic generated data even Morse has taken a back seat and using electronic data is far faster than Morse so uses less power per message.

I suppose we must add the power used by cell sites to our power used. But years ago every BT exchange as well as a huge bank of batteries had a large generator to maintain the exchange today just a battery in each rack ensures it still works with a power outage so clearly telephones now use less power.

By 1994 I was sending emails my address back than was [email protected] and I am sure it took more power than than it does now.

 

[JohnW2]

Exact figures hardly matter the point was using a voltage dropper was extremely wasteful when compared with a transformer or switched mode power supply.

We can certainly agree about that - at least in summer. In winter those TVs contributed significantly to the heating!

All around my house the power has dropped except for the washing machine. I fail to understand why but hot and cold fill types have gone. Which is a real pain when water is heated with gas or solid fuel.

I used to ask that question all the time - but the answer I was given seems simple and very credible. The fill volumes of WMs are now very much less than they used to be. In a house with stored hot water, the hot water drawn out of the cylinder would often not even reach the machine by the time it had drawn enough water (fairly cold water from the hot pipework). The only effect would therefore be to draw hot water out of the cylinder into pipes from which th heat would be 'wasted' (again, at least in summer)! Of course, if one has a combi-boiler or other imediate source of hot water sitting next to the WM then, even today, it would be nice to be able to use that.

Kind Regards, John

 

[winston1]

But years ago every BT exchange as well as a huge bank of batteries had a large generator to maintain the exchange today just a battery in each rack ensures it still works with a power outage so clearly telephones now use less power.

In the days of mechanical switching such as stronger a lot of power was consumed while setting up calls but very little in idle mode. The batteries were to cover peak calling time. It also worked whatever the temperature.

Modern digital exchanges take a constant power whether calls are made or not. They are also very fussy about temperature so exchanges are temperature controlled with heaters/air cons as required.

Taking all this into account the overall average power is about the same.

 

[big-all]

I used to ask that question all the time - but the answer I was given seems simple and very credible. The fill volumes of WMs are now very much less than they used to be. In a house with stored hot water, the hot water drawn out of the cylinder would often not even reach the machine by the time it had drawn enough water (fairly cold water from the hot pipework). The only effect would therefore be to draw hot water out of the cylinder into pipes from which th heat would be 'wasted' (again, at least in summer)! Of course, if one has a combi-boiler or other imediate source of hot water sitting next to the WM then, even today, it would be nice to be able to use that.

Kind Regards, John

that point bugs me i have a tank heated by gas at 1/3 the cost off electric most off the contents is not used as its a gravity system i need to run off a whopping 1.2L before hot comes through off course i cant use that water as its single fill
i then have to heat both the water tank and the washing machine to get the hot water

now i used to use a hose to fill via the soap drawer but when i worked out a complete cycle off the machine including warming the water would use around 900-1250w and only around 300-400w for the heating [1750-2000w for5-6 mins] it just wasnt worth the 4p a week i saved lol

 

[JohnD]

I still have a hot-fill washer, and run the kitchen hot tap briefly before starting it. With a HW cylinder there is less delay than with a combi.

Don't know about economy, but it keeps the soap-drawer clean and may knock 9 minutes or so off the wash time.

 

[ericmark]

You make a good point about the amount of cold water drawn before the hot arrives however I was given a different reason. Some items for example egg are better removed with cold water than hot. In fact hot water can fix the stain rather than wash it out. So starting cold then heating actually cleans the cloths better.

Also at a 40° wash filling with hot water could mean it is too hot. It would require the machine to be mixing the water all the time and the switching between hot and cold fill where the hot water varies in temperature is near impossible to ensure for all installations.

My house starts cold and warms up as water is drawn but to turn off the tap will cause an amount of cold in the pipe as the boiler re-starts. My mothers house has a small store in the boiler so as we found using the shower the water gets hot then goes cold again then gets hot again and stays hot. How could you design a washing machine to cope with that?

My son when living on a narrow boat had a problem loads of hot water from the aga but no washing machine could use that water and shore supply was 4 amp. He tried a 3kW inverter with 6kW peak to run washing machine from the 380 Ah bank of batteries but the cheap Chinese inverter gave out blue smoke and failed. He moved birth to one with a 6A MCB (B type) and in spite washing machine rated at 2.3 kW this worked OK. Which shows how little water is heated and how little energy is used.

In one house I stayed at the hot water was circulated so when any tap was turned on near immediate hot water. This system however requires a storage tank and all hot water pipes well lagged.

There were gas fridges and gas tumble driers but these seem to have all gone. I looked at gas fridge in a caravan and it does not even hit Energy rating D with low voltage electric it has to be A+ although extra low voltage DC units are again often not even D rated.

As time goes by those items we never really worried about have become large users of power. My free to air TV box can't measure power used on stand-by it is that low. The Sky box is a huge 10W on stand-by as the LNB remains powered up. So much for 1W limit.

 

[big-all]

the duel fill would have cost about £35-50 more so not economic in its own right
the machine it replaced had not once had its heating element used
but every time i used it i used the hot hose to fill

as an aside i love my new tumble dryer as it must have a moisture sensor as it will run for around 20 mins by which time synthetics are dry
restart another say 15 mins the mixes are dry restart again a further 10 mins everything else is iron dry

all i actually do is rather than select program or level is to press power on an start it does the rest automatically each time it finishes i remove the dry stuff and start again

 

[JohnD]

There were gas fridges and gas tumble driers but these seem to have all gone.

"White Knight" gas tumble driers are available and score well for performance and economy on "Which" tests. They do need to be connected and serviced by a gasman.

 

[JohnW2]

that point bugs me i have a tank heated by gas at 1/3 the cost off electric most off the contents is not used as its a gravity system i need to run off a whopping 1.2L before hot comes through off course i cant use that water as its single fill ... i then have to heat both the water tank and the washing machine to get the hot water ... now i used to use a hose to fill via the soap drawer ...

Thinking aloud ... if one were only interested in fairly hot washing cycles, what would happen if one fed a single-fill machine only from the hot supply (and ran a nearby tap to get the water up to temp before firing up the machine)? Indeed, if one wanted a cooler wash cycle, one could run the tap a bit less before turning the machine on! However, life is short and I'm not sure that all this hassle is necessarily worth expending energy on in relation to the small benefit that would result!

Kind Regards, John

 

[big-all]

yes thats similar to what i used to do except it would be a milk bottle very very hot water 3 milk bottles hot 2 bottle then hot fill only with the heating turned off

 

[JohnW2]

yes thats similar to what i used to do except it would be a milk bottle very very hot water 3 milk bottles hot 2 bottle then hot fill only with the heating turned off

Fair enough, but it would be a bit more convenient if the (single fill) machine were plumbed into the hot supply, wouldn't it?

Kind Regards, John

 

[big-all]

i stopped doing all that a few years ago when i actually found the saving where pence so not worth the time and trouble