Energy efficiency optimisation of the climate control systems of a data centre is necessary on both environmental and economic grounds. In environmental terms it represents reduced CO2 emissions, first and foremost through reducing power consumption to the minimum possible. The economic considerations are based principally on the investment and ongoing operating costs. The basic climate concept has considerable influence here, and the correct choice of technology forms the foundation of efficiency.

Schroff has published an interesting white paper on this subject, downloadable from the company's website at http://www.schroff.co.uk/datacom.

The paper is concerned with various concepts for server cabinet heat dissipation. Assuming the highest possible dissipation loss per cabinet, cooling efficiency and costs are examined for three different cooling concepts. Concept I is a design with cold and hot aisles and pure air cooling. Concept II is a similar structure but with hot and cold aisle containment, and retains pure air cooling. Concept III is a design with water-cooled server cabinets. As a starting point, a data centre with a total dissipation loss from all its servers of 300 kW was assumed. The average investment costs and ongoing running costs are examined and compared.