HOME BZU Mail Box Online Games Radio and TV Live Cricket Score All Albums
Go Back   BZU PAGES: Find Presentations, Reports, Student's Assignments and Daily Discussion; Bahauddin Zakariya University Multan Welcome to all the Students Articles Science & Technology


Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 15-01-2009, 03:35 AM   #1
Cut power costs with DC power
.BZU. .BZU. is offline 15-01-2009, 03:35 AM


Name:  it_energy_crisis_hp.jpg
Views: 89
Size:  9.1 KB
"10 power-saving myths debunked" generated a lot of interest and controversy. One topic that sparked plenty of discussion was the use of DC power in the data center. Because all computers use DC power internally, the basic concept is to limit the number of energy-wasting AC-to-DC conversions between the utility pad and the servers and to make those conversions as efficient as possible.
In a typical datacenter environment, power conversions abound along the path from the outside utility pad to the servers. With each conversion, some power is lost. The power starts at the utility pad at 16,000 VAC (volts alternating current), then converted to 440 VAC, to 220 VAC, then to 110 VAC before it reaches the UPSes feeding each server rack. Each UPS converts the incoming AC power to DC power, then back to AC. The UPSes then distribute that AC power to their respective servers -- where it's converted back to DC. As much as 50 to 70 percent of the electricity that comes into the datacenter is wasted throughout this long and winding conversion process.
There's a more efficient approach, one promoted by Validus DC Systems: taking the utility-supplied 13,000 VAC and converting it directly to 575 VDC (volts direct current) using an outdoor-rated conversion unit, then running power into the datacenter over 1.5-inch cabling. Each rack in the datacenter then has a 575-to-48-VDC converter that is 95 percent efficient. The direct DC approach can save users 50 percent or more between cooling savings and elimination of conversion losses, according to Ron Croce, COO of Validus.
It might be tempting to place an AC-DC conversion unit outside the datacenter so that heat dissipation occurs outdoors and to run 48 VDC into the datacenter. However, long runs at 48 VDC suffer from voltage drop, which means that a good deal of power is lost before it gets to the servers -- about 20 percent for every 100 feet of cabling.


One of the common arguments against using DC power in the datacenter is that machines don't support it: Most servers run on 110 VAC, which is then converted internally into 5 VDC and 12 VDC. However, with the use of DC power gaining some traction in datacenters, a number of server vendors, including HP, IBM, and Sun, are making DC power supplies available on some or all of their server lines, such that the machines can run on 48 VDC. HP's next generation of server chassis will be the same for all AC- and DC-powered systems, with modular power supplies.


Moreover, some large systems, such as the IBM P Series, are already designed to use 575 VDC. Although there is no current standard for high-voltage DC power in datacenters, Panduit and other companies are working on a standardized 400-VDC connector and cabling solution. General Electric is currently working on listing 600-VDC circuit breakers with the Underwriters Laboratories. These breakers already function at 600 VDC but were not previously rated because there was no demand.
In addition to providing cost savings through higher efficiency, DC systems may also provide an opportunity to expand datacenter capacity: Many existing datacenters are using only part of their available square footage because they can't get more power or cooling capacity. Some telecommunications centers are finding that newer rack systems require 100 watts per square foot rather than the old standard of 40 watts per square foot. Due to lack of space, their buildings can't support the 4-foot-thick bundles of cabling necessary for that much 48-VDC power. Moving to high-voltage DC could get around these limitations, because the required cabling would be just 1.5 inches thick.
In many areas, including New York, the San Francisco Bay Area, and Los Angeles, companies are unable to get additional power from the local utilities. Increasing the efficiency of existing systems could also allow companies to continue to use existing buildings and still expand datacenter capacity.
A high-voltage power system like that from Validus requires substantial installation and investment, including running large diameter cabling from the utility pad outside into the datacenter, installing the 575-to-48-VDC converters for each rack, and converting servers to 48 VDC. However, saving 50 percent or more on power over many years represents a big return. For companies that are unable to increase datacenter capacity by buying more power capacity, turning to DC may be the only solution.

__________________
(¯`v´¯)
`*.¸.*`

¸.*´¸.*´¨) ¸.*´¨)
(¸.*´ (¸.
Bzu Forum

Don't cry because it's over, smile because it happened

 
.BZU.'s Avatar
.BZU.


Join Date: Sep 2007
Location: near Govt College of Science Multan Pakistan
Posts: 9,674
Contact Number: Removed
Program / Discipline: BSIT
Class Roll Number: 07-15
Views: 902
Reply With Quote
Reply

Tags
costs, cut, power


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
The power of the first thought we think usman_latif_ch Quotes 0 25-12-2011 02:45 PM
the Power of truth momna gull Stories,Novels & Kahaniyan 0 17-12-2009 11:23 PM
physical power usman_latif_ch BZU Graphics and Wallpapers 1 14-03-2009 09:58 PM
US Air Power (US Air force) usman_latif_ch BZU Graphics and Wallpapers 0 03-03-2009 02:49 PM

Best view in Firefox
Almuslimeen.info | Cloud Computing | Dedicated server hosting
Note: All trademarks and copyrights held by respective owners. We will take action against any copyright violation if it is proved to us.

All times are GMT +5. The time now is 03:24 AM.

Powered by vBulletin® Version 3.8.2
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish.