When I replaced a 20 year old Ideal Mexico with a Worcester Bosch condensing combi I was quite surprised to notice that I was spending 20p (7.5kWh) a day just keeping the pilot light going. This was measured over three summer months with heating off, electric hot water, and no gas used for cooking (I was rebuilding the kitchen so cooker). So yes
60UKP a year is probably correct. The old boiler was pretty basic and I suspect any heating effect from the pilot would be insignificant: much of the day and night the heating is off and the heat would be lost to the cold air in the flue.
Well, if your boiler with pilot light is totally unused in the summer months it makes sense to turn it off totally. But you'd have saved more money by using it to heat your hot water rather than electricity.
Very good. I'm sure that "his elevator goes to the top floor" however. :-)
Seriously though, I've found that credibility with customers is a really important point - e.g. confidence that you know what you're doing and will look after them properly.
Many years ago, when I was first getting into technically supporting customers, somebody suggested that the way to go about things in the event of a problem is first to fix the customer and then to fix the problem. It has proved to be invaluable advice.
The radio wasn't cheap ;-) Although I note the even cheaper-feeling lightweight "brickette" for my mobile phone stays cool.
It's lost in the noise, though. I put out way more heat than these silly things, but if I cost money to run, at least it's pleasurable money. Like many people, I am alarmed how quickly a few watts here and there adds up over a year, both by the effect on my pocket and ultimately what it means in terms of fossil fuel use. (I reserve the right to go and waste a similar amount in my car over a weekend, though!)
AIUI, power factor can be lagging current (inductive) or leading current (capacitive). But there has to be a phase shift - either way - for there to be a power factor other than unity.
In simple linear circuits you are correct. But electronic products often have switch mode power supplies*. The input to these is (was) a bridge rectifier feeding a capacitor straight off the mains, so the capacitor is charged to around 340V DC (i.e. the mains peak voltage). High frequency switching circuits then feed the power through a transformer to the low voltage secondary circuits. But the point for this discussion, is that the input capacitor is only "topped up" for a brief period near the peak of the mains voltage cycle. Hence quite a large, but narrow (~2ms) current peak from the mains. This non-sinusoidal current has a higher than expected RMS level, and also contains a lot of harmonics - which are delivering no useful power. For example, a switched mode power supply drawing 100W of real power may well draw 0.75A rms from the mains. 0.75*240 = 180VA, and power factor can also be defined as real power (watts) divided by apparent power (VA). In this case 100/180, or 0.55 power factor.
Now all these harmonic currents were starting to adversely affect power distribution networks, so legislation** appeared about 10 years ago to restrict the harmonic content of the power drawn by higher power products (computers, TVs, anything electronic above 75W basically). Hence switch-mode power units with "power factor correction". For lower power stuff, (100W or so) a large inductor in the input can be used to spread the width of the current pulse and thus reduce its harmonic content. Otherwise a variety of electronic switching circuits can be used to force the product to draw a near sine wave of current from the mains. Power factors of 0.95 are easily achievable, 0.98-0.99 is typical.
*Even wallwarts and other 50Hz transformered products exhibit the same problem - there's still a diode-capacitor on the secondary of the transformer for the DC output. But this lower power stuff falls out of the scope of the legislation.
**Was EN60555, now EN61000-3-2.
Thanks for that Steven. I really should have done some research before jumping in!
Although I am aware of the pulses caused by a rectifier feeding a capacitor, I had never thought of it being a type of power factor but of course it is now you explain it so clearly.
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