Thanks for that link. An interesting article. At first I considered the fact that a data center should have already clean power, a central power conditioning unit, or such units at the final distribution nodes before circuits leave to the racks. But after some thought experiments I realize that this adds unneeded expense, failure points, and the all killing heat to an already complex problem. The power conditioning equipment is already half there in the required UPS.
A link to yet another article reveals new technology emerging known as delta conversion online. It is purported to be much more efficient albeit a little more costly than other technologies and appears to do this conversion to only a small portion of the energy transmitted through the device, while the larger portion is shunted through some kind of tap changer or solid state equivalent. Or... something.
It has power factor conversion which prevents the UPS and conditioning equipment from messing up the sinusoidal AC wave. As the article states and is a well known fact in the electrical field such a power factor can waste plenty of energy which is given off as heat in the distribution grid, and also wear and tear on the distribution and supply.
For a data center manager, that means replacements or refurbishments of distribution panels, feeders, transformers, and generators. It can also lead to a very nasty addendum to the utility bill, which I've heard can be 3-4 figures on a monthly basis.
It's a great shame that I cannot find any data on the percentile efficiency of UPS devices now that we've agreed that they are not simple relays with a battery backup, but a myriad of conditioning, transforming, and inverting equipment. The article I cited indeed says that such a relay with nothing else is very efficient, but has little to no voltage conditioning, and is probably more apt to keeping a hot-water heating pump running at a winter logging camp running at night than anything with any semblance of electronics.
If anyone can come up with some citations for data on the efficiency of various types of modern UPS/Conditioners please post them as I am very interested to know.
It may be the hinge on which the entire DC datacenter argument pivots, however as I mentioned before, it seems those 575VDC->48VDC converters with 90% efficiency are the keystone technology which burns holes in all energy savings. It's like the storage battery for the electric car. Not enough technology exists to make it viable.
The data on this entire concept is shady at best, but from what I am gathering the point it all is to put one very large converter outdoors so that it does not contribute to the heat in the building which increases the energy needed and cost of capacity for cooling said building. Bringing those converters indoors defeats this purpose, and its my understanding that it is less efficient and generates more heat than the AC counterparts.
This brings up another point that I must ask at this conjecture. The power losses from high current low voltage DC transmission from the Power Center to the racks has gone up. Will it be a considerable source of heat to be dealt with by the HVAC?
1V of line drop per ampere on said line = 1W of heat into the air = 3.413BTU per hour
I would love to see some data on this claim of greater efficiency, and just plain "how it works" for the DC-DC solid state transformer versus the AC-AC wound transformers. So far all I've seen is a 90% efficient solid state which face it, sucks.
I know someone who had his entire arm severely burned by an electric shock who I surmise might greatly disagree with you, fail to dignify you with a response, or quite possibly spit in your face for being a retard.
Citation: "My arm is burned. I don't wanna be an electrician any more."
Half as many amps == half as many power strips, half as many UPS devices, half as much wire, etc.
|
This is all utterly and completely false. Number of amps does not affect number of power strips as other posters have proven with math the first computer could have done. (20 == 20 => true)
The number of amps does not affect the number or capacity of UPS devices; it is Watts (commonly referred to as volt-amps) which dictates this, and it remains constant for a specific device no matter the supply voltage.
Your wire savings formula is flawed, unless the 240/415V technique is used as proposed (sort of) by another poster.
As mentioned by another poster, data centers are 3 phase electrical installations. This means there are three wires with alternating voltage in them, and they are all at peak at different times. A wiring technique is used in many installations called "Edison Three Wire" (I have no idea if they use this in data centers, but if they don't, they're stupid) This brings two live wires and one neutral wire to a location requiring two circuits of a given amperage. Let's call it 30A since this requires 10GA wire on a short run from the panel. Two Circuits, three wires. If you remove the ability to use Edison three wire by using 208 V circuits involving no neutral and two live wires, you increase the wire usage by 50%. An up in voltage yields a down in voltage by the same factor. The savings in current is only 42%. 150% of the number of wires times 57% as much ampacity. 17A requires 12GA wire, or run 14GA wire and a 15A circuit breaker which you pray no one trips on a daily basis. (Wow that's reliable)
This does not factor in the need by law for each circuit to have a separate ground wire, adding to the number of wires.
10GA wire has a cross sectional area of 10.4 thousand circular mils or kcmil. (mil = 0.001 inch) (1 circular mil is when you have circle radius 0.001 inch.)
For arguments sake and the fact that calculations dictated that a circuit now needs 17A down from 30A, we'll use 12GA wire. If you want to argue that it could be 14GA consider the fact that if you cut the available current by 2A you will likely need to increase the number of circuits to an enclosure or other fixture such as cooling or lighting. This will require larger distribution panels, bigger feeder cables, larger conduits, and all around more electrical capacity when dealing with things such as generators and UPS. This will eat into the savings.
Your new wire is 65% as much copper as the old wire. You require 150% as many wires not counting grounding/bonding. Your total mass of copper used is now 97.5% as much as before. A total savings of: precisely dick.
Or, you can double the voltage of every circuit in the data center and leave the electrical network topology the same. This requires new transformers, new distribution equipment, and now run the risk of never being able to provide a customer a 120V circuit for their wall-wart powered device. (I'm assuming that's a transformer block, many of which are now supporting 240V anyway) You could save about 60% as much copper mass, and then spend 10x more replacing all the other equipment which delivers the electricity around the data center, keeping in mind the cost of hiring a certified electrician to install this is tremendous.
Wire is the cheapest piece of equipment in the entire building, and it's the only thing that will be saved in the 240V datacenter, even if you start a brand new building from scratch with this in mind from the first mark on the design plan. Get over it. No one wants to do it.
Perhaps an electrical engineer could come up with some more promising data for converting data centers to 240V up from 120V, however I'm quite certain an EE wouldn't say "WHERE'S MY FISH YOU IDIOT"
Slashdot Mirror
A link to yet another article reveals new technology emerging known as delta conversion online. It is purported to be much more efficient albeit a little more costly than other technologies and appears to do this conversion to only a small portion of the energy transmitted through the device, while the larger portion is shunted through some kind of tap changer or solid state equivalent. Or... something.
It has power factor conversion which prevents the UPS and conditioning equipment from messing up the sinusoidal AC wave. As the article states and is a well known fact in the electrical field such a power factor can waste plenty of energy which is given off as heat in the distribution grid, and also wear and tear on the distribution and supply.
For a data center manager, that means replacements or refurbishments of distribution panels, feeders, transformers, and generators. It can also lead to a very nasty addendum to the utility bill, which I've heard can be 3-4 figures on a monthly basis.
It's a great shame that I cannot find any data on the percentile efficiency of UPS devices now that we've agreed that they are not simple relays with a battery backup, but a myriad of conditioning, transforming, and inverting equipment. The article I cited indeed says that such a relay with nothing else is very efficient, but has little to no voltage conditioning, and is probably more apt to keeping a hot-water heating pump running at a winter logging camp running at night than anything with any semblance of electronics.
If anyone can come up with some citations for data on the efficiency of various types of modern UPS/Conditioners please post them as I am very interested to know. It may be the hinge on which the entire DC datacenter argument pivots, however as I mentioned before, it seems those 575VDC->48VDC converters with 90% efficiency are the keystone technology which burns holes in all energy savings. It's like the storage battery for the electric car. Not enough technology exists to make it viable.
The data on this entire concept is shady at best, but from what I am gathering the point it all is to put one very large converter outdoors so that it does not contribute to the heat in the building which increases the energy needed and cost of capacity for cooling said building. Bringing those converters indoors defeats this purpose, and its my understanding that it is less efficient and generates more heat than the AC counterparts. This brings up another point that I must ask at this conjecture. The power losses from high current low voltage DC transmission from the Power Center to the racks has gone up. Will it be a considerable source of heat to be dealt with by the HVAC? 1V of line drop per ampere on said line = 1W of heat into the air = 3.413BTU per hour
MMMM yummy. (Yes I have tasted it)
I would love to see some data on this claim of greater efficiency, and just plain "how it works" for the DC-DC solid state transformer versus the AC-AC wound transformers. So far all I've seen is a 90% efficient solid state which face it, sucks.
I know someone who had his entire arm severely burned by an electric shock who I surmise might greatly disagree with you, fail to dignify you with a response, or quite possibly spit in your face for being a retard. Citation: "My arm is burned. I don't wanna be an electrician any more."
Half as many amps == half as many power strips, half as many UPS devices, half as much wire, etc.
|
This is all utterly and completely false. Number of amps does not affect number of power strips as other posters have proven with math the first computer could have done. (20 == 20 => true)
The number of amps does not affect the number or capacity of UPS devices; it is Watts (commonly referred to as volt-amps) which dictates this, and it remains constant for a specific device no matter the supply voltage.
Your wire savings formula is flawed, unless the 240/415V technique is used as proposed (sort of) by another poster.
As mentioned by another poster, data centers are 3 phase electrical installations. This means there are three wires with alternating voltage in them, and they are all at peak at different times. A wiring technique is used in many installations called "Edison Three Wire" (I have no idea if they use this in data centers, but if they don't, they're stupid) This brings two live wires and one neutral wire to a location requiring two circuits of a given amperage. Let's call it 30A since this requires 10GA wire on a short run from the panel. Two Circuits, three wires. If you remove the ability to use Edison three wire by using 208 V circuits involving no neutral and two live wires, you increase the wire usage by 50%. An up in voltage yields a down in voltage by the same factor. The savings in current is only 42%. 150% of the number of wires times 57% as much ampacity. 17A requires 12GA wire, or run 14GA wire and a 15A circuit breaker which you pray no one trips on a daily basis. (Wow that's reliable) This does not factor in the need by law for each circuit to have a separate ground wire, adding to the number of wires.
10GA wire has a cross sectional area of 10.4 thousand circular mils or kcmil. (mil = 0.001 inch) (1 circular mil is when you have circle radius 0.001 inch.)
12GA wire is 6.53kcmil
14GA wire is 4.11kcmil
Wikipedia on AWG
For arguments sake and the fact that calculations dictated that a circuit now needs 17A down from 30A, we'll use 12GA wire. If you want to argue that it could be 14GA consider the fact that if you cut the available current by 2A you will likely need to increase the number of circuits to an enclosure or other fixture such as cooling or lighting. This will require larger distribution panels, bigger feeder cables, larger conduits, and all around more electrical capacity when dealing with things such as generators and UPS. This will eat into the savings.
Your new wire is 65% as much copper as the old wire. You require 150% as many wires not counting grounding/bonding. Your total mass of copper used is now 97.5% as much as before. A total savings of: precisely dick.
Or, you can double the voltage of every circuit in the data center and leave the electrical network topology the same. This requires new transformers, new distribution equipment, and now run the risk of never being able to provide a customer a 120V circuit for their wall-wart powered device. (I'm assuming that's a transformer block, many of which are now supporting 240V anyway) You could save about 60% as much copper mass, and then spend 10x more replacing all the other equipment which delivers the electricity around the data center, keeping in mind the cost of hiring a certified electrician to install this is tremendous.
Wire is the cheapest piece of equipment in the entire building, and it's the only thing that will be saved in the 240V datacenter, even if you start a brand new building from scratch with this in mind from the first mark on the design plan. Get over it. No one wants to do it.
Perhaps an electrical engineer could come up with some more promising data for converting data centers to 240V up from 120V, however I'm quite certain an EE wouldn't say "WHERE'S MY FISH YOU IDIOT"
Topic Change
Drifting away from t