Energy-saving waterside economizers for data centers

With rising energy costs, free cooling can significantly reduce energy consumption and your carbon footprint.

Cooling a data center while reducing reliance on a mechanical chiller can unlock huge savings. With a waterside economizer, you can:

  • Cool water using the ambient conditions of the environment
  • Cut operating costs
  • Lower PUE (Power Usage Effectiveness) and CUE (Carbon Usage Effectiveness)
indirect evaporative cooling

Cooling with a chiller and chiller bypass

Waterside economizers save large amounts of energy by cooling water without relying on mechanical chillers. They are best suited for climates where the wet-bulb temperature falls below 78°F (25°C). Depending on local outside conditions, several system configurations can be used to maximize efficiency.

Trim chilling

Trim chilling combines a heat exchanger and a chiller to maintain desired fluid temperatures. In this setup, the cooling tower manages most of the load, while the chiller provides extra cooling only when needed. This hybrid approach balances energy savings with consistent thermal performance.

  • Reduces reliance on chillers and compressors
  • Cuts operating costs during cooler seasons
  • Maintains stable cooling and efficiency in variable climates

Economizer mode

Economizer mode enables full free cooling by bypassing the chiller entirely. In this approach, the cooling tower takes on the full load, supplying chilled water directly through a heat exchanger. This setup maximizes energy savings during extended periods when the outside temperature is naturally cold.

  • Allows complete chiller shutdown
  • Achieves maximum energy savings
  • Reduces wear on chillers for longer equipment life
computer chip

110 consecutive days of free-cooling and 2.13 million CNY saved every year

In a strategic move towards energy efficiency, a prominent Chinese semiconductor enterprise undertook an ambitious energy retrofit at their plant in Hefei. Guided by Alfa Laval’s expertise, the factory integrated its cooling and heating systems, which previously operated in isolation.

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How is Alfa Laval meeting the demands of tomorrow?

Reliability is critical for data centers, yet hidden inefficiencies can still lead to costly shutdowns. That’s where we come in.


Backed by our global team of experts, you can count on Alfa Laval to deliver the reliability you need to stay ahead and meet customers’ demands. With thermal imaging and performance analysis, we restore heat exchangers to over 95% thermal performance, preventing outages and cutting energy costs. It’s one more way we create value for data centers and help them prepare for tomorrow.

Ready to unlock the power of free cooling?

Waterside economizers are one of the smartest ways to lower PUE, energy costs, and carbon emissions. Talk to our data center cooling experts to see how Alfa Laval can help you unlock lasting value from free cooling.


Speak to a data center expert