In the previous issue of DatacenterDynamics Focus there were several articles on the issue of energy reduction in data centers. Energy reduction is clearly a must for the future, but we need to separate the realistic energy saving options from the not so realistic ones. A more down-to-earth view on this subject would help us set appropriate goals, set best practices, and give us the opportunity to take action on measures that really matter, such as reducing energy waste.

Currently, EvoSwitch has a Power Usage Effectiveness of 1,6, although a PUE of 2,0 is a typical data center value. Our ultimate goal is a state-of-the-art 1.2. I know Google claims to be a bit further along than us, probably because it doesn’t have to manage its data centers like we do, being a carrier-neutral data center. Google (and others) could even set up data centers in Iceland or Greenland because they don’t have to take into account restrictions on accessibility (by clients), connectivity and a variety of other needs that matter within a multiple client setting.

Seeing the real option

Theoretically, it is possible to put a data center in a container beneath the surface of water. It’s also possible to build floating data centers in the sea, which would mean immediate access to lots of cooling water. Google recently announced it will probably be experimenting with such solutions. For a carrier-neutral data center however, with a diversity of customers, these are not realistic options. The equipment stored in a data center has to be protected properly as well as allow people physical access to the premises. The combination of server equipment and water will certainly not appeal to many clients.

So let’s be realistic. First, your energy saving options depend on the nature of your data center operations. There’s no such thing as a general broad market solution for a low-energy data center infrastructure.

Second, size matters. It’s much more difficult for a large data center to lower the PUE to the ultimate level than it is for a small data center room located within a SME.

Cold corridors

A realistic energy saving option for every data center – even for older ones – is to implement a system such as a cold corridor. This is where cold and hot air are efficiently separated via different channels, so any short-circuiting between cold and hot air is prevented. This solution in itself brings energy saving benefits, but it also provides the opportunity to use higher inflow temperatures. Currently, we use an average inflow temperature of 24 degrees Celsius. This is possible only because cooling air in cold corridors is more equally distributed and hot spots are easily prevented from arising.

Furthermore, every data center – including those with legacy systems – could take various measures to improve airflow, for instance, by closing empty racks with covering panels and ensuring that the space beneath the floor is totally free of cables.

Efficient Uninterruptible Power Supply (UPS) technology, such as Delta Conversion from APC, would be another option for legacy data centers. With this method, the emergency power supply not only serves to condition the power supply but also makes a substantial contribution to a low-energy data center infrastructure.

Buliding a new data center

Building a completely new data center from the ground up would provide even more freedom in choosing which energy saving options to implement. Free Cooling technology – where the low outside air temperature is used for chilling water in a process or air-conditioning unit, is extremely efficient, although the climate has to be right for its use. It works well in the Netherlands, but Dubai, for example, would certainly struggle.

Within a newly developed data center environment it would also be possible to experiment with ground water cooling. This technique uses the stable temperature of groundwater to temper the internal climate of a building. However, exploiting this process can often depend on the level of bureaucratic restrictions in a country. Even though green and climate-friendly entrepreneurship is welcomed and stimulated in the Netherlands, for example, there is still resistance from different quarters on a solution such as ground water cooling.

Saving energy in a data center environment remains a pioneering journey for many. Weekly, our management team discusses options and invents new solutions. I think this is something every data center operator should do. It could result in the emergence of many best practices on energy saving.

This article first appeared in DatacenterDynamicsFOCUS Subscribe here