The Role of Uninterruptible Power Supplies Regarding Data Center Energy Efficiency

Computing has become a fixture in modern life, with people utilizing the internet for numerous business, education, communication and gaming amongst other reasons. No matter why consumers choose to use the internet however, they expect that their provider will supply them with satisfactory computing power and a reliable connection. This is where large IT facilities such as a data center come in.

Data centers house components such as servers, Lighting Control Panels, heating and cooling and storage devices, which are required to provide consumers with IT services. This equipment requires a large consistent amount of electrical energy, and can therefore be extremely expensive to run, with data centers throughout the United States said to consume more than 61 billion kilowatt hours of energy annually.

Components, Lighting Control Panels, Server Racks

As data center components from lighting control panels to server racks, are also sensitive to power events such as black outs, brown outs, spikes, surges and noise, they are generally protected by Uninterruptable Power Supplies (UPS). A UPS, as the name suggests, guards against such events by providing equipment with consistent energy in the event of an interruption to the facilities power supply. The issue with these devices however, is that they generally add significantly to the already high energy utilization of data installations.

UPS devices cause a data center’s energy consumption to increase, due to the fact that conventional battery-based double conversion UPS systems convert energy from Alternating Current (AC) to Direct Current (DC) and then back to alternating current, resulting in energy losses during transfer. It has also been found that UPS systems that are lightly loaded, which is generally the case in data installations, transfer power even less efficiently (Rumsey, 2006). UPS devices also need cooling, which requires further energy in the form of fans or other cooling equipment.

Rumsey (2006) interestingly states, that more efficient UPS devices can result in an instant energy saving of 20 to 30 percent, however, one must ask “What exactly constitutes an energy efficient UPS?” Numerous other authors discuss ‘green’ energy efficient UPS devices however, many of these papers are generated by computing component manufacturers, and state only that the product utilizes less power, generates less heat, and saves on energy costs, without actually supplying much supporting documentation.

The new generation of Eco UPS systems, which incorporate an energy saving ‘eco-mode’ are well explored in the existing literature however, they offer energy savings in the 2 to 4 percent range, which is not sufficient in the grand scheme. This energy saving is also said to come at a risk to computing components, owing to comprised electrical protection in some cases. Furthermore, many UPS systems offering an eco-mode also don’t actually require for it to be in use, meaning that data center technicians may choose to, or accidently, disable the energy saving function of such components.

In conclusion it can be noted that UPS devices can be a significant avenue of energy loss within data centers. It is believed that advances in technology are slowly bettering this situation; however, further developments are definitely needed in order to significantly improve the energy efficiency of these components.