Quick Summary
Balancing Water Usage Effectiveness (WUE) and Power Usage Effectiveness (PUE) is a primary challenge in modern data center operations.1 While increasing cooling tower Cycles of Concentration (CoC) significantly reduces water waste, it concentrates suspended solids and dissolved minerals, raising the risk of scale formation. By continuously reducing these suspended solids, side-stream filtration lowers the particulate load that contributes to fouling, helping broader chemical water-treatment programs operate under cleaner water conditions at higher cycles of concentration.
What You Will Learn:
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As digital infrastructure scales rapidly to support intensive AI workloads, data center operators face growing pressure to manage resource consumption sustainably.
Evaporative and adiabatic cooling systems can provide high energy efficiency under suitable climate and operating conditions, supporting lower Power Usage Effectiveness (PUE) targets.
However, because these systems consume water through evaporation, data centers must balance energy efficiency with increasing water-conservation requirements and local resource constraints. This relationship between water consumption and electrical demand represents the water-energy nexus of modern data center design.
Key Data Center Efficiency Metrics
PUE = Total Facility Annual Energy Use (kWh) / IT Equipment Annual Energy Use (kWh)
WUE = Annual Site Water Usage (Liters) / IT Equipment Annual Energy Use (kWh)
While a PUE of 1.0 represents perfect energy efficiency, driving WUE closer to zero is equally critical, especially in water-scarce regions where public utility grids and local watersheds are under severe seasonal stress.
Wet vs. Dry Cooling: The Resource Trade-Off
Fully dry cooling can eliminate on-site evaporative water use, but under certain climates and operating conditions, it may require more fan and compressor energy than evaporative cooling.4
What Are Cycles of Concentration?
To maintain high thermal efficiency while conserving water, operators of water-cooled systems focus on optimizing cooling tower chemistry.5 This is primarily achieved by increasing the Cycles of Concentration (CoC), the ratio that measures how many times water is recirculated before it must be discharged from the system as wastewater (blowdown).
CoC = Conductivity of Recirculating Water / Conductivity of Makeup Water
The Water-Saving Impact
Increasing cycles of concentration reduces both blowdown volumes and fresh makeup water demand.
According to the U.S. Department of Energy, increasing CoC from three to six can:
- Reduce cooling tower makeup water requirements by approximately 20%.
- Reduce blowdown by 50%.
The Scaling Risk
However, as water evaporates and dissolved minerals concentrate, the scaling limit of the water chemistry is quickly reached.
Calcium carbonate and silica concentrate to levels where they begin to precipitate out of solution, forming scale deposits on critical heat-transfer surfaces.
The Particulate Bottleneck at Higher Cycles
Operating at higher CoC is highly effective for water conservation, but it concentrates dissolved minerals and suspended solids inside the cooling loop. Dust, silt, and organic matter scrubbed from the ambient air by the cooling tower continuously build up in the recirculating water.
This accumulation of suspended solids creates significant operational risks:
- Particulate Contribution to Scale Deposition: Suspended particles can provide nucleation sites that contribute to mineral precipitation and scale deposition on critical heat-transfer surfaces.
- Fouling and Reduced Flow: Concentrated sediment settles in areas of low velocity, forming dead zones in the cooling tower basin and restricting flow through heat exchanger plates.
- Reduced Chemical Efficiency: Suspended organic and inorganic particulates can interfere with chemical treatment programs or increase the demand for dispersants and scale inhibitors, potentially reducing their overall effectiveness.
How Side-Stream Filtration Supports High-Cycle Operations
Physical filtration systems do not directly remove dissolved scale-forming mineral ions from water. However, high-efficiency physical filtration is a key enabler of advanced water-treatment strategies.
By continuously reducing suspended solids, Amiad’s filtration systems can lower the particulate load that contributes to fouling and scale deposition. Cleaner circulating water can support the facility’s broader chemical treatment program when operating at higher cycles of concentration.
DATA Klin: Key Operating Characteristics
- Side-stream flow: The DATA Klin system is engineered to continuously filter a side-stream loop treating 5% to 15% of the total circulating flow.
- Filtration technology: The system is powered by Spin Klin™ NOVA polymeric disc technology.
- 3D depth filtration: Its compressed, diagonally grooved discs form a 3D depth-filtration matrix.
- Filtration degree: The system captures fine particulates down to 55μm.
- Continuous operation: The automated, low-pressure-drop system provides continuous particle control without interrupting the main cooling-water circulation.
Parallel Industrial Validation: Side-Stream Filtration in Action
To understand the practical impact of side-stream filtration on evaporative cooling loops, we can examine Amiad’s proven experience in high-stakes cooling environments:
Case Study: Cooling Tower Sidestream Filtration Upgrade, Australia
Challenge
The evaporative cooling tower system at a large commercial shopping center in Newcastle, Australia, required an upgrade to improve water quality and operational efficiency.
The existing outdated automatic hydraulic screen filter was struggling to handle the heavy particulate load, resulting in:
- Frequent cooling tower draining
- Manual basin cleaning
- High chemical consumption
- High water consumption
Solution
Amiad, alongside its integration partner, deployed a skid-mounted side-stream package featuring:
- An automatic 4″ Mini Sigma filter
- A 100-micron screen
- An ADI-P controller
Results
Following commissioning, the system operated reliably to keep the towers clean. The upgrade:
- Reduced chemical consumption
- Reduced the labor costs associated with manual cleaning
- Delivered a significant improvement in general tower cleanliness during routine inspections
Read the full Cooling Tower Sidestream Filtration Upgrade case study.
Conclusion: Balancing Efficiency and Reliability
By integrating automated side-stream filtration to continuously reduce suspended solids, data center operators can lower particulate fouling and scale-deposition risks. This physical protection supports broader chemical treatment programs and may help facilities operate at higher cycles of concentration while reducing blowdown and improving water efficiency.
