Go green, buy a G8!

[Studio263]

Many people think that old TV sets use more electricity than new ones. Most of us know that that isn’t true, but here’s some amusing proof.

The first picture comes from a leaflet distributed by The Electricity Council in 1980. It shows how long many popular appliances will run on one “unit”, that is 1kW/h. In the television section there’s our old friend the Philips G8, which they reckon will go for 6 hours on one unit. I can’t remember what the power consumption of the G8 was but they had a 205V HT rail that powered everything which had about 500mA of load on it, so allowing for losses in the power supply regulator and the tube heater (powered from an small extra transformer) just under 200W seems about right.

Fast forward to now and a recent electricity bill shows similar data for modern appliances. For 1 kW/h you now only get 4 hours, is that what they call “progress”? My most modern set, a Beovision MX4000 (OK, not that modern…), only needs 90W for a bright, sharp picture. Strange how things have gone.

Bonus points: Can you name the music centre and the tape recorder shown on the old leaflet?

[Reelman]

If that is 3 horizontal sliders and the microphone cover open it is a Philips N4416. There should be a horizontal balance control under the meters though.
Peter

[1955APREN]

HI
I was under the impression that power supplies like the G8 and the Bush1122
were not liked by the electrical supply people because they only draw current on the positive half cycle of the mains supply . Possible the reason for the low consumption .

Can I have go at the music centre
KB ITT

[FERNSEH]

And that's only part of the story. The power supply does indeed draw it's power from the mains positive half cycle, but if that wasn't bad enough it is only a small part of the + half cycle where the power is drawn.
I'm planning to construct the ultimate G8, mine will have a switched mode power supply instead of the thyristor PSU.

DFWB.

[Herald1360]

Not the reason for the low consumption, but certainly the cause of distorted mains waveforms and harmonics and noise dumped into the network, all of which make it difficult (ie more expensive) to provide a clean supply generally.

A well designed modern switching PSU should cause less aggro to the supply than even the old transformer/rectifier/capacitor linear front end units.

[Radio Wrangler]

The torque taken by a generator is proportional to the current being taken, plus some ripple from the multiple phases. So all the TVs and radios with half-wave rectifiers on each phase of the mains all take their short but sharp surges of current at the same time, and the shock loads on the turbines and shafts at the power station are nasty.

Even with full wave rectifiers contributing only half-size shock loads, but twice as many per rev it's still a problem. That's why legislation was done to demand power factor correction of all loads above a certain wattage. Unfortunately they got this wrong, they never forsaw the spread of immense numbers of tiny devices like LED lamps and chargers for portable doodads.

David

[ms660]

Someone said that the Philips G8 consumes 200 Watts.

Our modern telly consumes 40 Watts.

Make of it what you will.

Lawrence.

[Tazman1966]

That said, modern tellies are probably switched on for a much longer viewing day...

[Herald1360]

Our 39" LCD job says 92W max, 55W typical. About the same as the room lighting.

The 28" Philips flat front CRT it replaced was 180W if I remember correctly.

Average use is probably a couple of hours a day.

I believe the real power guzzlers are (were?) the various plasma and projection large screen jobs.

[vidjoman]

I think some people have missed the point - The old leaflet says you will get 6 hours use of a colour TV with 1Kw of power and the new one reduced the time to 4 hours for 1Kw, suggesting that a modern TV will consume 50% more power than the old G8. But then it's from an electricity supplier, and what do they know.

[Welsh Anorak]

Hi there
Just repaired a Panasonic plasma which quotes 380W which is about the same as a G6 or B&O hybrid! However plasmas varied in consumption depending on screen content. LCDs with CFL backlights were pretty constant. LCDs with LED backlights usually vary the illumination which keeps overall consumption down. Possibly the new leaflet is intended to encourage viewers to turn the TV off when not in the room - or in the house!
Glyn

[ms660]

Originally Posted by vidjoman

I think some people have missed the point - The old leaflet says you will get 6 hours use of a colour TV with 1Kw of power and the new one reduced the time to 4 hours for 1Kw, suggesting that a modern TV will consume 50% more power than the old G8. But then it's from an electricity supplier, and what do they know.

"Many people think that old TV sets use more electricity than new ones. Most of us know that that isn’t true"

May be that's where I got confused.

Lawrence.

[Tractorfan]

Hi,
It looks like my Philips N4418 with six vertical sliders.
Cheers, Pete.

[broadgage]

For the same screen size a modern LCD TV will normally use appreciably less power than a similar size CRT set.
Unfortunately this is negated by the trend towards much larger screen sizes than were usual in the CRT era.
Few CRT sets exceeded 32 inches, but twice that (which is four times the area) is becoming common for LCD sets.

[julie_m]

Yes, but modern TV sets don't even seem to give you the full 25.4 millimetres on the inch these days .....

[AC/HL]

This is one of those satisfying arguments that can have an outcome to suit any point of view!

[julie_m]

There is certainly an argument to be made that keeping an older, less efficient appliance going is saving the energy required to make a replacement. There is a breakeven point, though, where replacing a TV or whatever with a new one that uses less power becomes worthwhile.

It's just simple simultaneous equations; the point at which two straight-line graphs meet (energy used by new telly plotted against time has a shallow slope, but an offset on the Y axis due to the energy used in manufacture; energy used by old TV has a steeper slope, but starts from zero on the day the new set was made.) Eventually, the two will cross over; and that is the perfect time to replace it.

[Phil G4SPZ]

It's often the case that improvements in energy efficiency are counteracted by other factors, such as more appliances or greater frequency of use. The big issue these days is the standby power consumption of modern appliances, but happily most manufacturers seem to be addressing this. Switching off at the mains, if possible, is always best.

[Welsh Anorak]

Hi there
Standby performance has improved drastically over the past thirty five years. The first sets that had standby circuits tended to use transformers which did use a lot of current giving rise to the alarmist claim that some sets used as much electricity in standby as when working (erroneous but good copy).
EU directives in the Nineties addressed this by giving standby targets of five watts, then two, then eventually one. Many ingeneous circuits were devised such as running a SMPS at a very high frequency with a close-coupled winding on the transformer to keep the 5v running - thing of Salora's IPSALO circuit. Now the trend is to use two power supplies, the standby 5v and the main set's supply. Luckily the size of screen has no bearing on the power consumption of the standby circuit.
I'm often asked which is better - to leave in standby or switch off completely. Advice on this is difficuclt to give - electronics like a nice even temperature and the power distributors dislike 'gulps' on the mains. But switching off at the mains results in zero power consumption and zero component wear.
I think the main problem is not the current consumption - which per inch of LCD TV display is far lower than with CRT designs - but the fact that most people tend to switch the TV on first thing in the morning and leave it till late at night, viewer or no viewer. Against this switching off or into standby becomes almost irrelevant.
To return to Tim's original point, I suspect the good old 22" G8 was being compared with (say) a 42" LCD in which case, yes, the statistics are correct!
Glyn

[Okto1984]

I keep hearing that modern devices are greener than ever, but the true environmental impact of things is always more complex than it seems and some modern things are worse. Flat screens I think are much worse than CRT sets. The fact that the LED and LCD types use less energy per square cm of screen is true, but it's not the full picture. Typical flat screens are much bigger than typical CRT sets, so as a whole, most TVs use more energy than they did 20 years ago (although modern sets don't need a set top box that uses another ~20 watt or so). They also tend to be replaced more often. Until the early 2000s, my general impression was that people didn't replace their TVs that often. A 10 or 15 year old set was common place, even in the sitting room, but not any more. You might think the rush to buy flat screens and HD sets has caused a brief spike in replacements the past few years, but actually many people are now on their second, third or more HD flat screen. You can even buy them at the supermarket. TVs have become cheaper, shorter lasting items that we buy more often. A further, greater problem is nitrogen trifluoride, which is commonly used to etch the panels during manufacturing. It's a long lasting greenhouse gas (estimated to last over 700 years) and has a global warming potential 17,200 times greater than CO2, meaning every gram has as much effect as 17.2 kg of CO2.

Anyway, TVs are a good example of how we've got to think about a whole range of issues and not just electrical efficiency. The advice to replace old CRT sets with 'energy saving' LED/LCD screens is just not based on enough information.

As for stand by energy use, I think the claim some items use more energy in standby is true, but misunderstood. I think the reality is, if you leave something in standby for a long time and use it infrequently, it will use more energy in standby than the short times when it's actually in use. My early 80s B&O uses 1 watt in standby, and about 75 watt in use. So I can leave it on 75 hours stand by or one hour of use and use the same amount of electricity. If I leave it in standby all the time and only watch one hour of TV a week, I'd actually be using more energy in standby than I would while watching it. However, leaving a tv on standby all the time is a bad idea, so it's always off at the switch when not in use. The fire risk of standby is more important than the energy saving message. But if we want to make an eco message, burning your house down (something that has happened to me on account of a TV left on standby) is quite a carbon footprint.