The rising cost of energy has put the squeeze on the data center—these days, typically 30 percent of a data center’s operating costs go to pay its electric bill. The ever-increasing demand for more processing power and storage capacity, along with the shift to high-density computing, has helped drive energy expenses through the roof.  In addition, concern for the environment has many corporations, including the systems vendors, focused on energy consumption and the reduction of carbon dioxide (CO2) emissions. It’s no wonder that many enterprises consider escalating power and cooling demands to be their biggest IT problem.

Efficient servers can save millions of dollars

Power and cooling should be addressed at both the level of the server, as well as at the data center.  Enterprise systems vendor Dell uses a five-level holistic approach when engineering for energy efficiency: component; system; rack; row and room.  Small improvements in energy efficiency at any of these levels can save millions of dollars per year in large data center deployments.

The average server today draws 400 watts, four times as much as the servers of just ten years ago.   Moreover, many IT groups are replacing pedestal servers with high-density blade servers and other rack-mounted systems.  Although these new platforms deliver impressive processing power in a small footprint, their power-hungry CPU’s consume enormous amounts of electricity and emit more heat per foot of floor space.

In fact, it’s very difficult to produce enough cooling to enable a rack fully populated by servers to perform at its theoretical optimum.  It’s prudent to select and balance systems based on application requirements, with the goal of using less power inside processors and memory.  Low power processors, such as AMD’s Opteron and Intel’s new Xeon Low Voltage processors, are an excellent way to cut power consumption.

Although a lot of focus has been on the processor and the energy consumed, it is important to consider the entire server system.  Other components inside the server, such as power supplies, hard drives and other components, when combined, account for more power consumption than the processor.  System vendors have recognized the need to balance performance with energy consumed and are focused on providing systems optimized for both.

Data center cooling—not a lot of hot air

Cooling server and storage arrays can cost a small fortune.  In fact, air conditioning a data center can cost as much as the electric power consumed by IT systems. 

For some data centers, heat generation has reached the point that additional cooling capacity is not practicable, either for cost or reliability reasons. Cutting-edge research in energy technology is exploring hydrogen fuel cells as alternative power sources and nanofluid cooling systems for data centers, but those will likely take years before they are real options.

Progress is being made, however, as alliances and industry standards groups are addressing these issues, such as The Green Grid, an association of information technology professionals seeking to lower the overall consumption of power in data centers around the globe. (Source: www.thegreengrid.org)

To prevent overheating, an adequate supply of cool air must flow to server and storage intakes as quickly as the equipment consumes it. It’s important to install systems and design HVAC airflow so that chilled air can be efficiently directed.  If system or switch racks are stacked too closely together, warm air from exhausts can flow back and recirculate into other rack intakes. 

Some relatively simple solutions can yield impressive results. By deploying air exchangers that attach to the back of racked devices, hot air can be directly routed to the cooling system, rather than rising through the rack and heating other equipment.

Today’s best practices use a hot aisle/cold aisle approach to cooling, in which rack intakes on both sides of a cooling aisle face each other.  Adjacent “hot” aisles have exhaust vents facing each other.  Interestingly, it’s important not to cool these exhaust areas because the warm return temperature enables the cooling system to operate more efficiently.

To optimize data center cooling, it’s necessary to eliminate gaps between racked equipment.  Use blanking panels within racks to block airflow between servers.  The goal is to maximize the delivery of chilled air to intakes in cold aisles and to keep exhaust aisles as warm as possible.

Data center managers can do several things to keep the lid on power consumption: identify opportunities to eliminate unnecessary software (thereby decreasing the number of servers), consolidate servers and storage, virtualize servers, and move network switches out of the data center. 

Leading vendors commit to energy efficiency and the environment

Server vendors like Dell have introduced energy-efficient products to help customers reduce operating costs and to help reduce harmful emissions.  For example, Dell recently introduced the world’s first energy smart servers, which consume 25 percent less power than the previous generation, while delivering up to twice the performance.  Many innovations contribute to these gains, such as lower voltage processors, demand-based switching that reduces power draw during non-peak times, high efficiency power supplies and variable fan speeds.

To help businesses address the challenge of data center cooling, Dell offers a Data Center Environment Assessment service.  This service evaluates both existing and planned deployments, providing plans for HVAC, cooling and power delivery systems to enable data centers to adopt high-density, racked servers and achieve maximum efficiency.

For more information, see www.dell.com/energy and www.dell.com/earth.