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 centers 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 Center 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)
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.
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 cool their data center most
effectively & efficiently with 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.
Excool understand differences and understands there is not a ‘one size fits all method’ but
with emergence of new technologies the options are 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.