Data Growth

Following the methodology given in the article “On Global Electricity Usage of Communication Technology: Trends to 2030” from 2015, we updated the data from “Cisco Global Cloud Index: Forecast and Methodology, 2016–2021. White Paper” to obtain the most up to date figures. The figures are only until 2021. Therefore, we applied the average growth rate from 2016-2021 to calculate the prediction up until 2030.

This consumption considers Global Data Centre IP Traffic:

To end users
To data centres
Within data centres
From consumers
From businesses
From cloud storage

Data centre consumption is predicted to grow by 24.7%, leading to a consumption of 4,150 TWh for 2030. This alarming figure is more than ten times the UK electricity consumption in 2017 of 336 TWh.

Electricity usage in Data Centres sectored

The alarming figure shown before can be classified into different systems inside de Data centre. As shown in the graph below [4], the cooling system can reach to consume the half of that consumption; the server loads can be the 36% and auxiliary systems such as the light and the battery could be 14%. Therefore, in order to reduce the consumption from the cooling systems, a brief cooling systems market review is going to be done.

Cooling Technologies in Data Centres

Data centre cooling systems are generally classified into one of the following:

Air cooling
Liquid cooling
Free cooling

Air cooling

Cold Aisle/Hot Aisle

Air cooling systems are the most common in data centres currently. Heat removal is generally achieved by a heat exchanger that transfers heat energy from one fluid to another. Air cooling uses air as the primary coolant.

This distribution makes cold air circulate in an underfloor plenum and is released in aisles in front of the racks which then exits through the back. It becomes hot air as it passes though the rack and IT components. Hot air ascends and is moved out though the roof to a computer room air-conditioning unit (CRAC) and is chilled through a heat exchanger.

Cold/hot Aisle Air Containment

The functioning is similar to the cold aisle/hot aisle system. However, in this either the cold or hot aisle are separated so that cold and hot air cannot be blend. The isolated air is moved to and from the CRAC unit through a closed circuit.

In-rack heat extraction is a more efficient way to remove the heat as the heat exchange occurs directly at the heat source.

Liquid cooling

This involves different cooling designs within liquids. The warm units are chilled by a heat exchanger in which the coolant is a liquid, or through immersion cooling (direct or indirect).

Liquid cooling can be circulated through pipes placed adjacent to the rack or even inside, in order to remove the heat from the ambient air close to the heat source (direct liquid cooled). The server components can also be immersed in a coolant bath, being directly in contact with the coolant (direct immersion cooling), thus increasing the heat transfer; or not directly in contact with the coolant (indirect immersion cooling).

Free cooling

This cooling system is based on using the natural surroundings of a data centre to cool it down (surrounding air, river water, ocean water). Heat naturally flows from hot source to cold. Therefore, if the temperature difference between the inside of the data centre and the outside is big enough, the heat will naturally flow from the server room to the outside. This enables saving energy as elements to transfer the medium are not required anymore.