Green Hosting

Green IT and green hosting has been in the news for several years. The technical solutions to save energy in hosting exist. Nevertheless relatively few datacenters are green. The reason for this is simple: Converting a traditional datacenter is quite complex especially as downtime is unacceptable. This means that only new datacenters with the ambition to be green can be optimized.
Greenshift has chosen the EvoSwitch datacenter in the Netherlands. EvoSwitch is one of the few green co-location centers and they are very ambitious about reducing energy consumption.
The common metric of the shade of green of a datacenter is the Power Usage Effectiveness (PUE). EvoSwitch has a PUE of 1.6, which is considered the best possible effectiveness for a co-location center today. EvoSwitch is also certified to be CO2 neutral. The latest generation of hosting modules in the datacenter will have a PUE of close to 1.0.

Free cooling

Traditional datacenters use standard compressor based cooling systems which were used when minimizing energy consumption was not a requirement. Today, so called free cooling systems exist, and companies such as EvoSwitch are using them in a production environment in order to minimise energy waste by the cooling system. The free cooling principle is based on heat exchange with a naturally cooler environment, such as the outside air, water or soil. Recovered heat can also be reused by local buildings or industry.

Sealed Cold corridor concept

The cold corridor architecture is a non technical concept that optimises the cooling by creating sealed cold corridors in front of the servers. The cold air is pulled though the servers by the servers’ internal fans and expelled as warmer air into the adjacent corridor which is warmed by the servers heat. The warm air in the warm corridor is then sent through the free cooling system. The gain in energy economy is twofold. The warm corridor represents only half of the volume of the server room, which means that less air needs to be cooled. Also, the warm corridor is warmer than the average room temperature would be if cold/warm corridors were not separated. The warmer than usual air can be more efficiently cooled by the cooling system.

Delta conversion UPS

Uninterruptable power supplies (UPS) are generally relatively inefficient. All the power is converted from AC to DC and back to AC. This results in much of the power being dissipated as heat. This is happening while the UPS is connected and not only during power failure when the load draws a lot of power.
A delta conversion UPS only acts like a standard UPS during a power failure. During normal operation the delta converter provides the full power directly to the load. When the load draws a lot of power a delta conversion UPS provides the possible amount of electric power directly and supplements the extra power needed from the batteries.

Inflow temperature

Green datacenters such as EvoSwitch apply another method to reduce energy consumption. Their inflow temperature is admitted to be slightly higher than in traditional datacenters, up to a temperature which doesn’t put the hardware at risk. As each additional degree to be cooled requires more energy, a non negligible energy saving can be obtained by this simple idea.