Green data centers help the bottom line

* Why energy efficiency in data centers is financially sound

Data centers are the biggest consumers of utility power in most large companies. Power needs range from 1 kilowatt per rack to more than 25 kilowatts per rack for dense blade servers. With rising prices in the energy markets, the electricity bill for your data centers could take a big bite out of your budgets. Increasing energy efficiency in the data center is not only an environmentally friendly strategy, but also a smart way to cut costs.

One way to increase energy efficiency is to run power and cooling units as close as possible to their maximum capacity, increasing the operational efficiency. But in many data centers, the exact opposite is the case. Data centers are designed with redundant cooling and power configurations - for every kilowatt of power demand, two kilowatts are provided on redundant circuits.

As redundancy increases, utilization decreases. In a fully redundant system, utilization cannot exceed 25%. At this range, both power and cooling systems exhibit their lowest levels of efficiency. For example, if a power system loses up to 5% of its total capacity to heat regardless of utilization (the static loss), at 25% utilization you are losing a fifth of your input power.

Data center managers who want to control their cooling and power costs are caught in a potential dilemma: high redundancy means worst-case efficiency. At the same time, provisioning cooling and power is extremely disruptive. In most cases, you have to shut down your data center to re-engineer your power or cooling. So many data center managers invest in cooling and heating based on the maximum projected demand. That can result in very low utilization - you’ve built a data center for the future and your electricity bills are also futuristically huge.

Here are some steps that can lead to a cleaner data center:

* Focus high-power and high-density cooling systems on a part of your data center rather than the whole data center. Essentially, you can build a Tier-II data center with a section dedicated to high-density computing and designed to Tier-IV standards.

* Enclosed hot aisles can concentrate heat dissipated from blade racks. That way you can apply your cooling as close as possible to the heat source. Concentrating heat is counter-intuitive, but it greatly increases the efficiency of cooling systems. A few degrees Fahrenheit difference can double your effective cooling capacity.

* Use scalable and modular power and cooling systems. By building only the capacity you need, you can operate the systems at higher utilization and therefore higher efficiency.

With some planning and better design, you can dramatically change the energy efficiency of your data centers. You will be helping to reduce energy demand, and cut your costs at the same time. Save the planet by hugging your rack-mounted servers.

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