A typical data center is a huge consumer of electricity. But less than half of the electricity actually is used by IT equipment. The majority of a data center’s energy costs are generated by the electric power system, the cooling system, and lighting.
This electrical inefficiency in data centers results in an enormous loss of capital for enterprises and raises larger environmental concerns.
Overall, according to an APC by Schneider Electric white paper, more than 60 million megawatt hours per year of electricity are wasted on data center power and cooling infrastructures.
While a data center team can’t do much about the global totals, it can take steps to reduce the power consumption of its own data center support equipment.
There are five contributors to electrical inefficiency in the data center.
Inefficient power equipment
Uninterruptible power supplies (UPS), transformers, switches and wiring all consume power in the course of doing their jobs. While power enters the data center in the form of electrical energy, virtually all of it – 99.99% – exits the data center as heat. (The miniscule remainder is converted by the data center’s IT equipment into computing.)
Don’t be fooled by equipment ratings that claim misleadingly high efficiency values in excess of 90%. They won’t do that in the real world. And, of course, the cooling system will deploy to address heat generated by the rest of the equipment, whether the heat is the result of wasted power or not. That’s a double energy waste.
Inefficient cooling equipment
Just as inefficient power equipment wastes electricity and generates heat, so does cooling equipment.
Ironic, perhaps, but the chillers, cooling towers, condensers and pumps in the typical data center actually waste more heat than the power equipment. Thus, increasing the efficiency of the cooling equipment can benefit overall system energy efficiency in two ways.
Power consumption of lighting
Lights, to no one’s surprise, consume electricity and generate heat. This sets off a chain reaction in the typical data center that goes something like this: Lights raise the data center temperature, triggering the cooling system, which then consumes more electricity. So lights can increase energy costs by generating heat and requiring cooling.
It’s often tempting for an enterprise to oversize its data center relative to its IT load. This can occur because the enterprise overestimated its IT load and thus built overly large power and cooling systems, or because the enterprise built its power and cooling system with plans to increase the IT load in the future.
Whatever the reason, over-sizing is one of the major causes of energy waste. Over-sized power and cooling systems can dramatically lower a system’s electrical efficiency, leading to perpetual energy waste.
Poor physical configuration of the data center’s IT equipment can lead to an enormous waste of energy. Yet virtually all operating data centers have configuration problems.
Poor configurations of IT equipment can wreak havoc on cooling equipment, generally forcing it to work harder – and thus use more electricity – than it would have to if it were better designed.
Some data centers are so poorly configured that one cooling unit may be dehumidifying while another is humidifying, canceling each other out and making each other work harder. And your energy bill goes up again.
For more information on data center efficiency, read the APC by Schneider Electric white paper, An Improved Architecture for High-Efficiency, High-Density Data Centers.