Stability of 240v supply under FIT tarrif?

[John Rumm]

Where is the heat that needs ventilating coming from harry?

[harryagain]

There is a bridge (full wave) rectifier feeding a resistor & capacitor in parallel hence I is leading V. Not a circuit that serves any useful purpose. It might represent a bit of wire. And not a "Peak clipper" And the power consumed is trivial. What bearing has this on the OP?

[harryagain]

Most of it goes on the fans shifting air.

[harryagain]

Most of it goes on fans and pumps shifting air and water.

[Andy Burns]

The fans that are drawing air from the cold aisle and exhausting it to the hot aisle are *internal* to the servers, therefore powered by the DC PSU in the servers.

[harryagain]

It comes from the heatsinks on electronic components and from people in these data centres. Also from the lighting, the screens (CRT or flat). From cooking and coffee making.

But mostly from solar gain. Hence the idea of buggering off elsewhere where it is cold/solar gain is less.

[harryagain]

it's not them that does it.

[Andy Burns]

They run like ghost ships

Ever heard of the phrase "lights off computing"?

There's probbly one screen per several hundred servers, sitting on a sad little trolley with a mouse and keyboard, first dibs to who needs it.

[The Natural Philosopher]

you havent been in a dark office ever, have you harry?

keep digging..i'll get the popcorn.

[Vir Campestris]

Errmmm...

"Most data centers use just as much non-computing or ?overhead? energy (like cooling and power conversion) as they do to power their servers."

Andy

[Vir Campestris]

Place my son works in has its own substations, and about 6 people in it. Maybe a kilowatt for the people. There are very few screens (most are headless) the lights are off when there's no-one near. And there aren't any windows, which cuts down the solar gain somewhat...

It all comes out of the electronics. Mostly the fat things with heatsinks, but not all.

Andy

[John Rumm]

Correct - and it represents the typical front end of most SMPSUs.

(R1 is there simply to represent the back end load part of the PSU, R2 is simply a measurement point).

No, its not leading in the traditional sense.

Have a look at some typical SMPSU circuits - rectifying the incoming mains, and using the rectified DC to charge a capacitor is a common feature.

The resulting significant non linearity of the current load has led to the required introduction of PFC in the input stages of the PSU.

The following should be simple enough to understand:

Huh?

Look at the current waveform... when does it peak? If its going to cause a voltage drop on the supply, where in the waveform do you expect it will cause it.

or significant - it depends on the component values. However the relevant point is the nature of the current waveform and the distorting effect this has on the supply.

I am sure you are bright enough to work it out.

[Huge]

Solar gain? Datacentres don't have windows, you useless sack of pus.

[harryagain]

Capcitive reactance in the mains is extirely cancellled out by the massively greater inductive reactance. (Due to motors etc)

[harryagain]

That part of it is trivial. The large part is removing the heat from the building.

[harryagain]

You dozy bugger. Solar gain occurs even without windows. Through the roof for example.

[The Natural Philosopher]

On 02/10/13 08:26, harryagain wrote: ..... extirely cancellled out

Is that what happens when a train is derailed?

[The Natural Philosopher]

I see sums are not yur strong point

[tony sayer]

So -what- does it then ?..

Be a bit more specific please...

[The Other Mike]

So all that money, in excess of a billion quid in England and Wales, spent on static VAR compensators, shunt reactors, capacitor banks, etc is simply a waste of money then?

You better get onto OFGEM straight away and get them to investigate this massive waste of money.

Just so you know where they are when you have a word with OFGEM, have a look at page 17 of this document. Look for the things in magenta and green.

Please let us know how you get on with OFGEM. You may want to let the Daily Mail know while you are at it. They are well known and have an international reputation for accurate, non biased reporting of 'facts' They will love your story.