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 those data center operators evaluating their cooling system options.
Data centers can have a heavy demand for water. IT equipment requires enormous amounts of energy to operate whilst generating considerable amounts of heat. The cooling process of traditional direct and indirect evaporative cooling solutions often involves that as soon as outdoor ambient conditions allow the solutions will be evaporating water for cooling with cooling towers or evaporative coolers. When water is cheap and plentiful, this makes sense due to savings in electricity and the cost benefits.
It is important to understand that by reducing the water consumption at the data center, the water consumption's incumbrance goes back to the source at the thermoelectric power generation process.
The average water consumption factor for electricity in the United States is 0.576 gallons/kWh. 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.
Traditional direct and indirect evaporative cooling solutions for data centres across the world have shown that they significantly reduce energy consumption compared to other technologies, but historically have resulted in relatively high-water consumption.
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. The effectiveness of evaporative cooling either direct or indirect is very location-dependent since regions with a drier less humid climate results in greater efficiency of the system.
For data centre designers, it is very often thought that there is no middle ground for data center cooling. The final decision will often drive the final solution 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 system). High energy consumption and no water usage. (typically, chilled water, DX or pumped refrigerant)
Utilising data centre 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.
Traditionally a cooling system would either switch to a mechanical DX or chilled watercooling mode or an adiabatic/evaporative mode (including mechanical DX mode for top-up) offering little or no flexibility.
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 method or combination of cooling methods to use to cool their data center most effectively and efficiently with the flexibility to change as the internal and external conditions vary, for example an increase in IT load or if power and water costs increase and decrease.
Excool understand differences and understands there is not a ‘one size fits all method’ but with emergence of new technologies the options of water vs no water are no longer polar opposite, and a flexible middle ground can easily be achieved.
When designing data centers for a sustainable future, the client can be positive that water use in the cooling of an adiabatic/evaporative solution can be closely aligned with the efficiency and sustainability goals of low energy, reducing carbon emissions and conserving water.