Joe Miller of NetApp posted a question:
PUE = 1.05? How does that break down? Transformer loss, UPS loss, lights, cooling how can that add up? Just the AHUs matching the air flow created by the racked equipment fans is a least 5% of the IT load...
and KC Mares has responded:
"Excellent question, and you are correct: a PuE of 1.05 is very difficult to achieve and this is a goal to change the standard conventional data center further. So let's break this down. If you supply the racks and/or computers directly with higher voltage power, let's say 480 Volts AC, you essentially only have the losses from one transformer (if utility service is higher than 480) and possibly one rectifier, although this rectifier could be part of the UPS if DC distribution is used from there. UPS losses can be minimized with high-efficiency rotary systems. Properly size all of these items and you have 1-4% losses just from the electrical system.
So how do we then cool the servers? Place the data center in a cool environment with lots of cool water and/or air on tap and allow a wider temperature and humidity band than typical--after all, servers can handle much wider temperature and humidity bands than we humans prefer. Combined, these can eliminate the need for a chiller plant yet use water chilled from Mother Earth right to the necessary components in the servers instead of pushing air, since water is so much more efficient to move (objects) than is air.
Doing so, the system will have minor pump losses moving "earth-chilled" water to the system components requiring cooling, while allow outside air to cool the "room". I say earth-chilled because this water would only be mechanically moved but not chilled, and room, because the cooler air should be allowed to flow through the space but not need to be pushed by fans. This allows our creativity to design what a data center building should look like and where it might be located. After all, a data center really only needs three things to narrow down location: power, network latency and people, and each often allows for a wide berth of location, sometimes spanning continents and even oceans.
I know all of this may sound esoteric, but that is the secret sauce that allows for so much innovative design to the traditional data center, in location, form and function. These are designs that I am working on with clients since leaving Yahoo, as I start a new career overlapping my experiences in IT and knowledge of sustainability and energy efficiency." Thanks KC!!!!!
Just recapping, the charter for the Critical Facilities Round Table, a five year-old group in the San Francisco Bay area, is to provide an open forum to share information and look at cutting edge solutions and technologies and improve technical competence as well as proactively influence the mission critical industry, its regulators, and partners.
Diesel exhaust is a complex mixture of gases, vapors and particles (articles have a carbon core with large surface areas) as well as hundreds of individual chemical compounds (over 40 compounds are listed by the State of California as Toxic Air Contaminants (TACs), both organics and metals, that can affect long term health. These particulate matter do emit from diesel generators. Ground level ozone is urban smog: it causes severe asthma and lung damage because it stays in the lungs. Exposure to diesel exhaust is associated with an increase in lung cancer, chronic respiratory system damage and increased symptoms of respiratory irritation.
(This is different from the ozone level high in the sky that we are all familiar with from global warming conversations.) The health risk assessments studies have shown that a single current standby emergency diesel engine running 50 hours per year, like a typical large chemical plant or petroleum refiner running every day of the year, both result in an increased cancer risk of 1 – 10 in a million. Of course a big plant distributes more particulate, but the risk from each source is similar. Air dispersion is different for both cases, so this is simply a way to describe risk without all the details. State of the art ultra low sulphur and catalytic engines are included in this analysis above.
Diesel energy without controls pollutants are six times as noxious (30 pounds of NOx pollutant per megawatt hour of electricity generated) as out-of-state coal power (5 tons of NOx pollutants per megawatt hour of electricity generated. In contrast natural gas turbine cogeneration systems produce just .1 pounds of NOx pollutants per megawatt hour of electricity generated.
A representative from the Demand Response Operations for PG&E, spoke next. A heat-storm in both northern and southern California could present a problem and rolling black- or brown-outs. Energy efficiency is defined as permanent reduction of energy usage while maintaining the same comfort levels. Demand response is different. It is defined like this: when requested, customers alter their routine to reduce peak demand during a relatively few critical hours of the year and are rewarded for reduction. Utility demand response programs are established for reliability as well as pricing issues.
California’s “loading order” prioritizes the types of
resources that utilities and other ‘load serving entities’ must secure: energy
efficiency, demand reduction, renewables, distributed generation, efficient
clean fossil-fueled Central- state Generation, and finally transmission.
On July 25, 2006, a very hot
load was nearly 21,000 MWs whereas the average load is around 13,000 MWs. A hot day can add
8,000 MWs of demand to the California grid system. That load keeps growing every year. Companies respond
differently to the hot days that generate peak load. Some ratepayers
send their employees home during peak hours – others use their backup
generators. I learned a great deal that day about the complexities of demand response and generating power to sell back to the utilities. Have a green day!