As demand for energy rises, the power sector’s water usage is expected to increase even further, straining scarce water resources. Thirty-six countries around the world already suffer from high or extremely high water stress. Concern over water usage has generated an interesting debate around sustainability for data center operators evaluating their cooling system options.
Data centers can have a heavy demand for water, because IT equipment requires enormous amounts of energy to operate, while also generating considerable amounts of heat. Traditional direct and indirect evaporative cooling solutions often involve evaporating large volumes of water as soon as outdoor ambient conditions allow. When water is cheap and plentiful, this makes sense due to the savings in electricity and the cost benefits.
The reason that evaporative cooling solutions are so effective is that water is a more efficient medium than air for removing heat, because evaporation increases the cooling process. But while these cooling solutions have shown that they significantly reduce energy consumption compared to other technologies, historically they've resulted in relatively high water consumption. Plus, the effectiveness of both direct and indirect evaporative cooling is very location dependent, since a drier, less humid climate results in greater efficiency of the system.
For data center designers, it is very often thought that there is no middle ground for data center cooling. The final decision is generally based on the key demands of the client. The options invariably are either:
- Keep energy consumption low and consume significant volumes of water (typically, direct or indirect evaporative cooling systems)
- High energy consumption and no water usage (typically, chilled water, DX or pumped refrigerant)
Utilizing data center cooling solutions that can efficiently and effectively operate in free cooling mode in low to mild external temperatures means data center mechanical systems require less energy. The dilemma often occurs once free cooling is no longer available.
In that situation, a cooling system would either switch to a mechanical DX or chilled water cooling mode or an adiabatic/evaporative mode (including mechanical DX mode for top-up), which offers little or no flexibility.
An often overlooked but crucial aspect of the decision for data center operators to understand is that typically by reducing the water consumption at the data center, the water consumption's incumbrance goes back to the source at the power generation plant. Therefore, even though local water consumption has been reduced, the overall water consumption in the cycle of power generation increases, as more energy has been generated. Using water at the data center reduces the inherent electrical losses associated with the power required for the cooling between the power generation plant and the data center.
Company Photos with the Queens Award for International Trade. https://www.excool.com/the-princess-royal-visits-excool/
Recent developments in indirect evaporative cooling technology have seen the emergence of a new type of cooling solution. The new technology allows the data center operators to determine which cooling method, or combination of cooling methods, will cool their data center most effectively and efficiently. It also offers the flexibility to change as the internal and external conditions vary, such as an increase in IT load or as power and water costs increase and decrease.
There is no one size fits all method, of course. But with emergence of new technologies, these two options, water vs. no water, are no longer polar opposites, and a flexible middle ground can easily be achieved. When designing data centers for a sustainable future, the client can be positive that the water use in adiabatic/evaporative solution can be closely aligned with the efficiency and sustainability goals of low energy, reducing carbon emissions and conserving water.
To learn more about designing data centers for a sustainable future, Excool's market-leading, next-generation cooling technology and more, visit https://www.excool.com/.
Telehouse North 2 Data Centre. London, UK. https://www.excool.com/excool-project-insight-telehouse-docklands-london/