What can data centre developers and operators do to optimise their energy consumption?
Examples of these opportunities are virtualisation and the use of ARM-based processors, which are designed to perform a smaller number of types of computer instructions so that they can operate at a higher speed. This provides outstanding performance at a fraction of the power. The technological development of both these options is making them a viable solution, but they are still outside of the remit of most data centre developers.
Good practical management of data centre space is still a suitable, basic way of reducing energy consumption. Making use of aisle containment systems, installing blanking panels into unused rack slots and providing brushed grommets into raised floor penetrations are all simple, yet effective, energy saving methods that can be implemented, but they are still forgotten in many smaller facilities.
Implementing aggressive power usage effectiveness (PUE) or NABERS Energy targets will also drive more energy saving initiatives and improvements within data centres. New facilities will find it easier to implement PUE targets as high efficiency equipment can be selected to reduce parasitic load requirements.
Implementing low PUE targets, such as energy efficient lighting, in existing facilities is also achievable, but it takes more financial backing and careful planning to realise. When equipment needs to be replaced, more energy efficient options can also be chosen.
Lastly, the application of machine learning for data centres has been used to optimise cooling system setpoints for variable outside conditions. Having optimum setpoints provides a number of marginal energy gains, that when aggregated can provide as much as 10-15 per cent energy savings on the cooling system.
Could more data centres use natural cooling and night cooling opportunities to save energy?
Free cooling opportunities are possible in many locations, especially if the air temperature that is supplied is in line with the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) guidelines (18°C-27°C).
With supply air temperatures of up to 27°C, we need outside air temperatures at 25°C or less to gain significant benefits from free cooling. Data centre managers then need to decide whether they are going to use direct or indirect free cooling. Indirect free cooling can be achieved via a heat wheel or heat exchanger as outside air contaminants or humidity levels do not restrict the use of free cooling, making it an attractive option.
There are definitely more opportunities to use this type of indirect free cooling in certain areas, particularly where the temperature falls below 19°C and the humidity is below 60 RH (relative humidity) for more than 2 500 hours per year.