Creating an Energy-Efficient IT Environment

The benefits of lower energy usage - a more efficient operations and reduced costs - are reason enough to investigate how a company could become more eco-friendly and 'green'.

For those who are likely to consider step to make an IT environment more efficient and sustainable, information about the measurements and best practices are available. The Greed Grid have created a simple, scalable tools and resources to make efficient computing easier. The Green Grid and its members that include end users, policy-makers, technology providers, facility architects and utility companies, work to improve resource efficiency in ecosystem of business computing.

Along with its PUE (power usage effectiveness), WUE (water usage effectiveness) and CUE (carbon usage effectiveness) metrics, Data Center Maturity Model, and recommendations for adopting server power management, virtualization and Eco Mode technology, The Green Grid has compiled a list of steps to help create a more energy-efficient IT environment.

Total Energy Calculation

The first step in understanding data energy consumption is to take an initial assessment of the power used in data centers. The data will give the idea of how efficient the data center is at using and sending power to its servers.


Making better use of the available IT resources is another important factor in the energy-saving effort. To make IT machines work more efficiently, virtualization is a key to consider.

The steps include taking an inventory of all IT machines operating in the environment and constructing a plan for consolidation based on needs. Every watt of power that a workspace doesn't need is a watt less to be cooled.

The components for the loads in the metrics, which can be described as follows:

    1. IT Equipment Energy. This includes the load associated with all of the IT equipment, including computer, storage, and network equipment, along with supplemental equipment such as KVM switches, monitors, and workstations/laptops used to monitor or otherwise control the data center. Following the definition of PUE, this value is the annual total.

    2. Total Data Center Energy. This includes the IT equipment energy and everything that supports the IT equipment load, including:

    • Power delivery components such as UPS, switch gear, generators, PDUs, batteries, and distribution losses external to the IT equipment.
    • Cooling system components such as chillers, computer room air conditioning units (CRACs), direct expansion air handler (DX) units, pumps, and cooling towers.
    • Other miscellaneous component loads such as data center lighting.
    • Other energy types beyond electricity, such as the natural gas that runs an absorption chiller.

    3. Total CO2 Emissions. This component includes the CO2 emissions from local and energy grid–based energy sources. Ideally, the CO2 emissions will be determined for the actual mix of energy delivered to the site (e.g., the electricity may have been generated from varying CO2-intensive plants - coal or gas generate more CO2 than hydro or wind. The mix also must include other energy sources such as natural gas, diesel fuel, etc.). The total CO2 emissions value will include all GHGs, such as CO2 and methane (CH4). All emissions will need to be converted to "CO2 equivalents."

    As recommended with PUE, the above component values are the annual total emissions.

Efficiency with Temperature

With PUE data and all machine energy usage at hand, the next step is to address facilities issues, and more specifically, temperature issues and cooling.

The initiatives can include: installing OEM variable speed drives (VSDs), upgrading CRAH (Computer Room Air Conditioners & Handlers) units, implementing rack airflow management, moving the CRAH control from the return air temperature to the rack inlet, and increasing the temperature set points of the CRAH and chiller units. Overall, improving cooling technologies can lead to massive energy and cost savings.

Controlling the Power

Natively controlling the power consumption of IT assets using IP-enabled energy management tools provides major efficiency gains. Enterprise energy management systems can monitor and control compute, network and storage assets.

Servers are a good place to start, and server power management (SPM) is a tool that many data centers are adopting, and can save as much as 33 percent of the energy used by a server, without affecting performance. There are a variety of ways that data centers of all sizes can take advantage of these methods.

The Future

Facebook recently became the first company to publicly announce its water usage effectiveness, a metric developed by The Green Grid. Understanding the WUE measurements will keep you ahead of the game, and with companies like Facebook taking the lead, WUE promises to be an increasingly important measurement going forward.

An ideal coolant has high thermal capacity, low viscosity, is low-cost and chemically inert, neither causing nor promoting corrosion of the cooling system. The most common coolant is water. With its abundance in nature, low-cost and high heat capacity makes it a suitable heat-transfer medium.

The Green Grid has proposed carbon usage effectiveness (CUE), to address carbon emissions associated with data centers. The impact of operational carbon usage is emerging as extremely important in the design, location, and operation of current and future data centers. When used in combination with the power usage effectiveness (PUE) metric, data center operators can quickly assess the sustainability of their data centers, compare the results, and determine if any energy efficiency and/or sustainability improvements need to be made.