The return of direct current: 400 VDC for Data CentersFollow article
…converting – transforming – converting – transforming… Large amounts of unused electricity simply disappear in data centers. Direct current improves the quality of the power supply and is therefore on the rise again: More and more electricity is supplied along the supply chain at least once in DC form in the areas of energy generation, transmission, storage and use.
Studies show that data centers consume approx. 3 % of the world's electricity and account for 2 % of total greenhouse gas emissions. This ecological footprint corresponds to the one from the airline industry. Energy losses can happen in various places: in processors, in cooling, in air-conditioning, but also in the distribution of power.
An obvious approach is to provide a data center with DC voltage. If a server is already working off DC power, it makes sense to continue using it as consistently as possible throughout the chain.
The DC power architecture contains not as many components as the AC power architecture. Efficiency increases by 10 % when various transformations and conversions are eliminated. Fewer components are installed quicker, are serviced faster, and cause less errors. According to a study conducted by NTT (Nippon Telegraph and Telephone), the reliability is expected to increase tenfold due to the system being less complex!
Further advantage: It is so much easier to integrate renewable energy sources such as photovoltaics, fuel cells or wind energy as these sources of energy can already provide the electricity as a direct current.
Data centers around the world (e.g. China, Japan, USA, Germany, Switzerland) already use DC technology. However to date, there have been no binding standards to adhere to. The IEC (International Electrotechnical Commission) has set out to create the missing link with standardized plug and socket devices according to TS 62735. Efforts are currently being made to create solutions for DC plug connections on the previous AC standard IEC 60320. There are different approaches so far for DC connectors, but they have not been able to prevail due to the pending standards. That is why various providers are working together in the IEC standardization body in order to replace the proprietary approaches with an internationally recognized standard.
It is important that the conversion of the voltage supply is gradual. It is only in this way that all the devices will not need to be switched from an AC to a DC supply at once. There need to be solutions that can feed the device with both an AC and a DC supply. The power supply units of the devices can process both supply voltages. It must be ensured that all the safety-relevant precautions are taken.
Where there is light, there is also shadow
The availability of DC components is still in its infancy. It needs a new approach. The use of a DC supply requires integral planning from the grid to the chip. And everything in between! Because there are still losses here - e.g. heat loss. What this means: There needs to be cooling systems with a DC supply. Also needed are air conditioning systems, fire protection systems, access control systems as well as building control systems and much more. All of these components should be equipped to operate with direct current.
Taking a look forward
The supply of a data center using direct current has tremendous potential. Not only does it offer the potential for saving energy, but also, to the same degree, savings on costs, space, resources and time. Furthermore, the supply of renewable energy sources offers the possibility of providing electricity directly for the data center as a direct current, without additional transformation or conversion processes. The quality of the DC-level power is better. This will result in the use of fewer components and, ultimately, greater reliability.
Availability is the keyword in the digital age. Everywhere and at any time.
AC vs. DC approach: The DC architecture uses far less components and allows the integration of renewable energy sources directly conversions.