How cool is your datacentre?

08-03-2012 - John Hatcher

Maintaining a stable physical environment in a data centre is vital and therefore must be carefully controlled. Allowing servers and storage to run at higher temperatures by installing a more effective cooling solution can have major benefits in terms of efficiency and the environment.  Leading players in the data centre industry such as Google, Intel, Sun and HP have been saving hundreds of thousands of dollars in cooling costs by raising the temperatures of their data centres.

A data centre is measured on how efficiently it uses its power with a PUE rating – Power Usage Effectiveness - which is the total facility power divided by the it equipment power.

For the last few decades, manufacturers of HVAC (heating, ventilation and air conditioning) equipment have been striving to improve efficiency. Demand for energy is rising and so are energy costs. Our increasing dependence on fossil fuels mean energy supplies are decreasing and the focus is now turning to environmental issues.  It is estimated that the Information and Communications Technologies (ICT) sector accounts for roughly 2% of global carbon emissions. Data centres are said to be responsible for 14% of the ICT footprint. A major effort must be made by data centre managers to take responsibility for the effects their data centres have on the environment and reduce the PUE of their data centres. For example, every degree of upward change in the baseline temperature of the data centre can save data centre managers up to 4% in energy costs. This is achieved by less frequent use of air conditioning, which saves the energy used to run cooling systems.

An ‘ideal’ PUE is 1.0, but the industry average is currently at 1.8. The legacy system average is 2.5; free cooling chillers would be around 1.6 and a direct airside economiser only 1.25. However, it is possible to get even closer to the ideal rating.

PEER 1 Hosting is bringing a new standard in data centre efficiency to Britain, predicting a PUE of 1.1, the lowest in the country by a considerable margin, for its new data centre in Portsmouth.

The company will become the first data centre in the world to work with Excool, a UK-based, innovative cooling technology specialist. Excool has spent two years developing and enhancing a blend of components used extensively in other sectors to create a product specifically for the data centre industry that delivers the most reliable and efficient data centre cooler available.

Excool’s cooling technology works by using adiabatic cooling through a modular external design. Indoor air is cooled by indirectly transferring the heat to the outdoor air through Excool’s unique and highly efficient heat exchange system and low energy fans. On hot days the temperature of the outdoor air stream is lowered significantly by the introduction of moisture. Through its simplicity Excool provides greater resilience and reliability than typical systems, and can provide up to 95% power reduction.

Deploying an effective cooling solution not only has a significant impact on the PUE rating of a data centre, it can also greatly cut cost. For example, a chilled water system with a 1.4 PUE may run up to around £400,000 per POD, whereas an Excool set up with a 1.1 PUE costs around £100,000.

When data centres use economiser cooling all of the servers are cooled using outside air. By not using chillers or air conditioners potentially vast amounts of money are saved.

By placing more importance on HVAC, IT companies can improve the efficiency and carbon footprint of their data centres, as well as cut costs.