PUE or ERE?
The energy effectiveness in a data center is often measured in PUE (Power Usage Effectiveness). It is a key performance indicator to quantify the efficient use of energy in a data center. It shows how much energy that is used by the servers in contrast to the other overhead equipment such as cooling, light, UPS etc. PUE is a global standard, under ISO/IEC 30134-2:2016. In a perfect world where all the energy that is delivered to the data center is used by the servers, the PUE would be 1.000
Older generations of data centers that reached a PUE of 1,3 were considered to be energy efficient in a world where most of the competitors had PUE over 1,5 or higher. But things have changed. In 2012 Microsoft new data center reached a PUE of 1,125 and at the same time Google´s new data center reached a PUE of 1,210 which was considered almost impossible to reach. Today we can achieve PUE as low as 1.070.
How to achieve a low PUE
In general terms, to achieve a low PUE the location of the data center could be a factor and the design of the data center itself. Normally a typical cooling system could consume roughly about 30-45 % of the total energy in a data center (global average). Data centers located in a cold climate such as the Nordics where you can use free cooling, will reduce the need for massive cooling systems that consume large amounts of energy.
The temperature in the physical data center is also a factor. In the early age of data centers, the temperature was usually around 15 °C or lower. Today server manufactures have an allowable range from 15-32°C, care should be taken running at high temperatures as server ventilation has been shown to increase its energy use at temperatures over 25°C.
Next Generation Data Center will absolutely have a low PUE, as close to 1.000 as possible. But if a low PUE means that you waste heat as efficient as possible, is that the best case for the environment and your economy? Do you waste a potential profit, where there is a need for your waste heat that you can get paid for?
"YIT as a constructor of Data Centers thinks it´s time to challenge the old way of measuring the efficiency in a data center. Do you agree, please contact your partner at YIT for further discussion."