)Why is PFC considered "green"?
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Why is PFC considered "green"?
While I know, that the PFC strives to get the PF near 1, I don't know whom it serves despite the energy producers. I know that the PF is the sine of the phase angle between voltage and current, which should be 0 in an ideal case. But I still don't know what should be wrong about a low PF, except most electricity companys not being able to bill correctly (which is good for me )
)Low power factor means you need to draw more current for the same (real) power. This leads to more loss of power during transmission from the power plant to you in the resistance of the wires. It also means that the power company has to use more resources to lay thicker cables etc.
It costs you money (because if it costs the power company, then you pay via increased prices), and wastes energy and resources.
It costs you money (because if it costs the power company, then you pay via increased prices), and wastes energy and resources.
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Das_Saunamies
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Ditto.
And while the power factor can be presented as a sine of the phase of the angle of the graph of the voltage and the current(I have no idea what I just said), the bottom line is what Mr Evil pointed out: the higher the PF, the less resources wasted in the effort to transform power from the supplied to the applied form.
And while the power factor can be presented as a sine of the phase of the angle of the graph of the voltage and the current(I have no idea what I just said), the bottom line is what Mr Evil pointed out: the higher the PF, the less resources wasted in the effort to transform power from the supplied to the applied form.
To give you an idea, check here. The angle between the red and the green arrow is the phase angle. U(t) is the voltage over time, I(t) is the current over time.
I didn't think about the losses due to higher currents if the PF isn't 1. Thanks for the hint.
I didn't think about the losses due to higher currents if the PF isn't 1. Thanks for the hint.
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Das_Saunamies
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Für den Link, danke. I liked the smooth animation, but I'm afraid algebra(or whatever field that is) is wasted on me. I'm only capable of playing with numbers, and to me efficiency is like:
Power input = x = 100% = 1
Power output = y < 100%
Power loss = z = 100%-x
Efficiency = 100%-z
So a machine with >80% efficiency(turns over 80% of given resources into results) would have an efficiency of >.8, and that would be it's PF value in the AC world of electricity(?). I haven't got a good grasp of the correct terms in the field due to a language barrier, but I do get the idea of higher currents(and thus power as voltage is static) equaling higher costs either directly(home) or indirectly(power companies).
Interesting to challenge and read up on things I've taken for granted.
Power input = x = 100% = 1
Power output = y < 100%
Power loss = z = 100%-x
Efficiency = 100%-z
So a machine with >80% efficiency(turns over 80% of given resources into results) would have an efficiency of >.8, and that would be it's PF value in the AC world of electricity(?). I haven't got a good grasp of the correct terms in the field due to a language barrier, but I do get the idea of higher currents(and thus power as voltage is static) equaling higher costs either directly(home) or indirectly(power companies).
Interesting to challenge and read up on things I've taken for granted.
It would all make more sense if we paid for electricity in some form of normalized amp-hours instead of watts. I found it funny that I measured two different CFL bulbs with my kill-a-watt. One was 15 watts and the other was 24 watts, but the 15 watter pulled 26VA and the 24 watter pulled only 24VA due to vastly superior PFC. The higher wattage bulb actually is "greener" to the power company since it pulls lower VA even though the wattage is higher.
It's physics, not algebra
No. Efficiency and PF are two different things. Efficieny is, as you said, Results/Resources. PF is only affecting the efficiency if you're taking the additional losses due to higher currents on the DC side into account. In theory, a PSU with a low PF could still have a high efficiency.
The higher currents do only a small harm to you. In fact, they benefit your electricity bill, because you pay for kilowatt-hours, which are Wh=voltage*current*PF*time, while the work you use is VAh=voltage*current*time, which is always smaller than the actual VAh, because PF is smaller than 1.
EDIT:In fact, these equations are kind of wrong because voltage and current change over time, so you would have to integrate over the time. But I don't know how to type integrals in a readable form and I don't know if you would understand them, no pun intended. And the results stay the same.
So, to conclude, if your PSU had a PF of 0, which would translate into a phase angle of 90°, you would pay nothing for your PC's power usage.
No. Efficiency and PF are two different things. Efficieny is, as you said, Results/Resources. PF is only affecting the efficiency if you're taking the additional losses due to higher currents on the DC side into account. In theory, a PSU with a low PF could still have a high efficiency.
The higher currents do only a small harm to you. In fact, they benefit your electricity bill, because you pay for kilowatt-hours, which are Wh=voltage*current*PF*time, while the work you use is VAh=voltage*current*time, which is always smaller than the actual VAh, because PF is smaller than 1.
EDIT:In fact, these equations are kind of wrong because voltage and current change over time, so you would have to integrate over the time. But I don't know how to type integrals in a readable form and I don't know if you would understand them, no pun intended. And the results stay the same.
So, to conclude, if your PSU had a PF of 0, which would translate into a phase angle of 90°, you would pay nothing for your PC's power usage.
That's it maybe: Greener to the power company
In fact, I have thought previously of buying a big fat capacitor and putting it in the circuit right between the socket and the PSU. Capacitors make a phase angle of 90°, which would completely destroy the near-perfect PF of my NeoHE and also the electricity company's income generated by my PC. But it's illegal...
In fact, I have thought previously of buying a big fat capacitor and putting it in the circuit right between the socket and the PSU. Capacitors make a phase angle of 90°, which would completely destroy the near-perfect PF of my NeoHE and also the electricity company's income generated by my PC. But it's illegal...
That's not correct. Your electricity meter measures real power (in Watts). This number is independent of the power factor.
If your PC draws 100W of real power, you'd have:
- 100W real power, 100VA apparent power at PF=1
- 100W real power, 200VA apparent power at PF=0.5
- 100W real power, 1000VA apparent power at PF=0.1
In any of those cases, your electricity bill would remain the same. PF=0 is impossible, as you would need an infinite current.
Power factor has nothing to do with your electricity bill! (unless you're an industrial customer) It also has nothing to do with efficiency at your side of your electricity meter! A better power factor increases efficiency a little at the power company's side, however.
If your PC draws 100W of real power, you'd have:
- 100W real power, 100VA apparent power at PF=1
- 100W real power, 200VA apparent power at PF=0.5
- 100W real power, 1000VA apparent power at PF=0.1
In any of those cases, your electricity bill would remain the same. PF=0 is impossible, as you would need an infinite current.
Power factor has nothing to do with your electricity bill! (unless you're an industrial customer) It also has nothing to do with efficiency at your side of your electricity meter! A better power factor increases efficiency a little at the power company's side, however.
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Das_Saunamies
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Okay, thanks for clearing up my delusions of Efficiency = PF.
I'm all for high-efficiency products from the green perspective. Less resources wasted, be it in any form or function, is less waste produced. And waste is baaad...! I may not know how they work precisely, in fact I'm sure I don't in light of recent events, but I understand the principles and some basic mechanics that allow me to put two and two together. A little extra money for less energy wasted(and that way resources) is money well invested.
I was assured by a member of the Green Party that the sixth nuclear power plant wouldn't be necessary if we used more higher-efficiency equipment in combination with local or alternative energy production. I'm not saying that 80Plus PSUs will make reactors obsolete, but I would be damn pleased if we didn't need one more!
I'm all for high-efficiency products from the green perspective. Less resources wasted, be it in any form or function, is less waste produced. And waste is baaad...! I may not know how they work precisely, in fact I'm sure I don't in light of recent events, but I understand the principles and some basic mechanics that allow me to put two and two together. A little extra money for less energy wasted(and that way resources) is money well invested.
I was assured by a member of the Green Party that the sixth nuclear power plant wouldn't be necessary if we used more higher-efficiency equipment in combination with local or alternative energy production. I'm not saying that 80Plus PSUs will make reactors obsolete, but I would be damn pleased if we didn't need one more!
The power company is sending out AC. The PSU is converting it to DC.
For the Power Co. It's still all about how much wattage you suck out of the wall. If your puter uses 100 w DC but the PSU is 50% efficient...you'd need 200w of AC to get your 100 w of DC. If it was a 100% efficient PSU..100w of AC gets you 100 W of DC. The "lost watts" mostly become HEAT (not good).
Don't let too much grad school math get the whole concept inverted. There is no downside to more efficiency. Active is the efficient way now to get that efficient and stable DC your puter eats.
I don't think there's a binding "green" definition but it TENDS to include high efficiency and no toxic elements in the components that would not recycle well.
For the Power Co. It's still all about how much wattage you suck out of the wall. If your puter uses 100 w DC but the PSU is 50% efficient...you'd need 200w of AC to get your 100 w of DC. If it was a 100% efficient PSU..100w of AC gets you 100 W of DC. The "lost watts" mostly become HEAT (not good).
Don't let too much grad school math get the whole concept inverted. There is no downside to more efficiency. Active is the efficient way now to get that efficient and stable DC your puter eats.
I don't think there's a binding "green" definition but it TENDS to include high efficiency and no toxic elements in the components that would not recycle well.
The other thing besides power lines is the generators. They need to supply the reactive power as well as the active power, While the reactive power doesn't require power input on the generator's shaft, it does require the current to flow through the generator windings. This means the generators need to have the capacity of the apparent power that is being supplied. And generator capacity is not cheap.
Dan's Data - PFC decoded.