Sustainable cooling of data centers

NDC-GARBE 30/11/2021

(Convenient translation of German version)

For climate protection, digitization is both a blessing and a curse. On the one hand, the increasing use of digital technologies raises energy consumption. On the other hand, it also opens up a range of new opportunities to counteract climate change.

Due to the digital transformation of recent years, data centers have become an indispensable asset for processing the enormous amount of data produced daily. At the same time, however, this drives up power consumption. In 2020, data centers in Frankfurt alone consumed about 1,600 GWh hours and thus 20 % of the city’s total electricity consumption. As a result, data centers are responsible for almost 2 % of global greenhouse gas emissions. To reduce this, in addition to server operations, it is necessary to keep an eye on the cooling technology. That is because 30-60 % of the energy requirement is accounted for by the cooling systems.

In the case of cooling systems, a distinction is made between two types:

Air Cooling

Air cooling systems are considered a proven technology and have been used for years. Cold air flows over and around the hardware. The resulting heat is dissipated by the air exchange. There is a distinction between room-, row- and rack-based systems. However, because modern workloads require a high density of racks and servers, data center space is limited. As a result, old air coolers have to be retrofitted, which is associated with high costs. In addition, air is not an efficient heat transfer agent (heat capacity: approx. 1.005 kJ / (kg K)). As a result, although the outside air is efficiently supported in cold regions, a lot of energy must be used to help in warmer regions.

Liquid Cooling

Liquid cooling systems are relatively new but offer great potential for sustainability. Therefore, modern data centers increasingly rely on this method, also due to the high efficiency (heat capacity: approx. 4.19 kJ / (kg K)). Liquid transfers heat better than air: 30 times higher thermal conductivity and therefore 4-fold the heat capacity. The systems can, for example, be attached to the rear walls of the computer systems using heat exchangers and cool the warm exhaust air directly with water. The systems require less space and thus allow a higher computing density. The entire construction area can thus be used more efficiently. In addition, the ideal location for the data center no longer depends on climatic conditions.

Further information and the entire article by Herbert Radlinger, VP Projects & Solutions at NDC-GARBE can be found here.