Data centres depend on reliable cooling.

And wherever water forms part of that cooling strategy, water quality becomes part of the site's critical infrastructure.

Whether the facility uses cooling towers, evaporative cooling, adiabatic systems, chilled-water circuits, closed cooling loops or water-cooled heat rejection, the condition of the water can directly affect efficiency, reliability and equipment life.

Hydra-Clear designs, manufactures, installs and maintains water treatment systems specifically for critical industrial applications.

For data centres, that means engineering water systems around one overriding requirement:

Keep the cooling infrastructure available.

Water Treatment for Data Centre Cooling

Cooling-water systems operate under very different conditions depending on the data centre design.

A site may incorporate:

• Cooling towers
• Evaporative condensers
• Adiabatic coolers
• Chilled-water systems
• Closed-loop cooling circuits
• Dry coolers with seasonal water assistance
• Heat exchangers
• Direct liquid cooling infrastructure
• Coolant distribution units
• Water-side economisation
• Hybrid heat-rejection systems

The correct water treatment strategy therefore depends on how water is being used.

Hydra-Clear starts with the system design, incoming water chemistry and cooling philosophy before determining the treatment process.

Cooling Tower Make-Up Water

Evaporative cooling systems deliberately evaporate water to reject heat.

The water evaporates.

The dissolved salts do not.

As evaporation takes place, calcium, magnesium, alkalinity, silica, chloride and other dissolved constituents become increasingly concentrated within the cooling circuit.

Eventually those concentrations have to be controlled through blowdown.

The quality of the incoming make-up water therefore has a direct influence on:

• Cycles of concentration
• Blowdown volume
• Scaling potential
• Corrosion risk
• Chemical consumption
• Water consumption
• Cooling efficiency

Improving make-up water quality can allow the cooling system to operate more effectively while reducing the quantity of water discharged to drain.

Softened Water for Cooling Systems

Water softening can be used to remove calcium and magnesium hardness before water enters the cooling system.

This can substantially reduce the potential for hardness scale formation.

Depending on the application, softened make-up water can allow higher cycles of concentration than untreated mains water.

However, softening does not reduce the total dissolved solids within the water.

Sodium, chloride, sulphate, silica and other dissolved constituents remain.

For some cooling systems, softening is sufficient.

For others, reverse osmosis provides a considerably greater opportunity.

Reverse Osmosis for Data Centre Cooling

Reverse osmosis removes a large proportion of dissolved salts from cooling-system make-up water.

This can significantly reduce the contaminant loading entering an evaporative cooling system.

Potential benefits can include:

• Increased cycles of concentration
• Reduced cooling tower blowdown
• Reduced make-up water consumption
• Lower scaling potential
• Reduced chemical demand
• More consistent cooling-water chemistry

RO does not automatically make sense for every data centre.

The economics depend on the incoming water chemistry, cooling demand, evaporation rate, current cycles of concentration and cost of water and wastewater.

Hydra-Clear can model these parameters to determine whether RO treatment provides a genuine operational benefit.

Why Cycles of Concentration Matter

Consider a cooling system supplied with mains water.

As water evaporates, the mineral concentration within the recirculating water increases.

If the system operates at three cycles of concentration, the dissolved constituents within the cooling circuit are approximately three times their concentration in the incoming make-up water.

Increasing the cycles of concentration reduces the amount of water that needs to be discharged through blowdown.

But the chemistry has to support it.

Push the concentration too far and the system can experience:

• Calcium carbonate scale
• Calcium sulphate deposition
• Silica deposition
• Increased chloride concentration
• Increased corrosion risk
• Reduced heat-transfer efficiency

This is why cooling-water optimisation is a chemistry problem rather than simply a controller setting.

Reduce Blowdown. Reduce Water Demand.

Water efficiency is becoming increasingly important in data centre design.

Where evaporative cooling is used, reducing unnecessary blowdown can provide substantial reductions in total site water consumption.

Improved make-up water quality can potentially allow more water to remain within the cooling process before it needs to be discharged.

That means less:

• Make-up water
• Blowdown
• Wastewater
• Chemical consumption
• Water-treatment demand

The correct treatment strategy needs to balance water recovery against scaling risk, corrosion control and microbiological management.

Maximising cycles at any cost is not good engineering.

Closed-Loop Cooling Water

Not all data centre cooling water is evaporative.

Closed chilled-water and heat-transfer loops have very different requirements.

Once correctly filled and commissioned, a closed loop should experience relatively little make-up.

In these systems, the emphasis moves away from reducing blowdown and towards maintaining stable water chemistry and protecting the cooling infrastructure.

Important considerations can include:

• Conductivity
• Hardness
• Chloride
• pH
• Dissolved oxygen
• Corrosion inhibitor concentration
• Glycol concentration
• Suspended solids
• Microbiological condition

Poor water quality can contribute to corrosion products, fouling, blocked strainers, heat-exchanger contamination and deterioration of system components.

Water Quality for Direct Liquid Cooling

As rack densities increase, more data centres are incorporating direct liquid cooling and other liquid-based thermal management technologies.

These systems introduce another important water-quality interface.

The cooling fluid requirements may be defined by the equipment or CDU manufacturer and can be significantly different from conventional cooling-tower chemistry.

Depending on the system, consideration may need to be given to:

• Conductivity
• Hardness
• Chloride
• pH
• Corrosion control
• Glycol concentration
• Particulate contamination
• Materials compatibility
• Microbiological stability

The water or coolant specification should therefore be established from the equipment requirements before the treatment system is designed.

We do not assume that "purified water" automatically means better cooling water.

The chemistry must suit the materials and the system.

Side-Stream Filtration

Cooling circuits can accumulate suspended material from corrosion products, airborne contamination and process debris.

Side-stream filtration continuously removes a proportion of the circulating water, filters it and returns it to the system.

Depending on the application, this can help reduce:

• Suspended solids
• Sediment
• Corrosion products
• Fouling
• Deposit formation

Hydra-Clear can design filtration systems using technologies such as:

• Bag filtration
• Cartridge filtration
• Multimedia filtration
• Automatic backwashing filtration
• Fine filtration
• Ultrafiltration

The filtration level is selected according to the actual cooling-system requirement.

Water Recovery & Reuse

A data centre water strategy should consider more than the incoming mains supply.

Depending on the site, opportunities may exist to recover water from:

• RO concentrate
• Cooling tower blowdown
• Rainwater
• Process wastewater
• Condensate
• Other site water streams

Recovered water may be suitable for direct reuse or may require additional treatment.

The correct question is not simply:

"Can this water be reused?"

It is:

"What treatment is required to make reuse reliable, and does the overall water balance make economic sense?"

Hydra-Clear can assess the source water, required reuse quality and treatment requirements before developing the recovery process.

Water Treatment Without Creating Another Single Point of Failure

For data centres, availability changes the way water treatment equipment should be designed.

A treatment plant serving critical cooling infrastructure cannot always be treated like an ordinary process-water skid.

Depending on the site requirements, Hydra-Clear can incorporate:

• Duty/standby pumps
• Duplex treatment trains
• Duty/assist operation
• N+1 capacity
• Automatic changeover
• Dual filtration
• Redundant instrumentation
• Buffer storage
• Emergency bypass
• Critical spare strategies

The redundancy philosophy should reflect the consequence of losing treated-water production.

If losing water means losing cooling capacity, that needs to be considered during the original design.

Modular Design for Data Centre Expansion

Data centre capacity rarely remains static.

Cooling and water infrastructure therefore needs to accommodate future phases without unnecessarily oversizing the complete treatment system on day one.

Hydra-Clear can design modular systems that allow future expansion through:

• Additional RO trains
• Additional softener vessels
• Modular filtration
• Additional transfer pumps
• Increased storage
• Spare pipework connections
• Expandable control panels
• Additional PLC I/O
• Future treatment stages

Where future phases are known, we can incorporate the required interfaces into the original design.

Instrumentation & Control

A critical water system needs visibility.

Hydra-Clear systems can incorporate Siemens PLC and HMI control with monitoring of parameters including:

• Flow
• Pressure
• Differential pressure
• Conductivity
• pH
• ORP
• Temperature
• Tank level
• Water quality
• Chemical dosing
• Pump status
• Filter condition

Automatic sequences can include:

• Duty/standby changeover
• Tank level control
• RO production control
• Conductivity diversion
• Chemical dosing
• Automatic flushing
• Filter backwashing
• Alarm escalation
• Emergency shutdown

BMS & SCADA Integration

A standalone water treatment system should not become an information island within a modern data centre.

Hydra-Clear control systems can be engineered to communicate with the wider facility controls where required.

This can include status and alarm signals for:

• System availability
• Tank level
• Water production
• Conductivity
• Pump condition
• Treatment plant fault
• Chemical level
• High or low pressure
• High differential pressure

The exact communication architecture is agreed during the controls design.

Monitor the Water Balance

A properly instrumented water system can provide considerably more information than a simple totaliser.

Depending on the application, we can monitor:

Incoming Water → Treated Water → Cooling Make-Up → Blowdown → Reject Water → Recovered Water

That allows the site to understand where its water is actually being used.

This can help identify:

• Increased consumption
• Excessive blowdown
• Treatment inefficiency
• Leaks
• Abnormal operating conditions
• Opportunities for recovery

You cannot optimise a water balance that you cannot measure.

Water Storage & Distribution

Treatment capacity and instantaneous demand are not necessarily the same thing.

Storage can therefore form an important part of the resilience strategy.

Hydra-Clear designs treated-water storage and distribution systems considering:

• Normal demand
• Peak demand
• Emergency demand
• Treatment production rate
• Buffer capacity
• Tank turnover
• Pump redundancy
• Distribution pressure
• Fill rates
• Low-level alarms

For critical applications, storage can provide valuable operating time if upstream treatment becomes temporarily unavailable.

Water Treatment for Multiple Cooling Phases

Large data centre developments may be constructed and commissioned in phases.

Hydra-Clear can design common water infrastructure capable of serving multiple stages while maintaining the ability to isolate, commission and expand individual areas.

This can include:

• Common pretreatment
• Central RO production
• Multiple distribution branches
• Independent storage systems
• Phased pump installations
• Modular treatment trains
• Future connection points

The aim is to avoid repeatedly rebuilding the water system as the facility expands.

Designed Around the Incoming Water

Data centres can be constructed almost anywhere.

The local water chemistry changes with them.

Two facilities with identical cooling technology can therefore require completely different water-treatment systems.

Important feedwater parameters can include:

• Hardness
• Alkalinity
• Conductivity
• Chloride
• Sulphate
• Silica
• Iron
• Manganese
• Turbidity
• pH
• Temperature

For large facilities or sites considering borehole, recovered or alternative water sources, a representative water analysis is essential.

The cooling technology may be standardised.

The water rarely is.

Data Centre Water Treatment Design

Hydra-Clear can provide treatment systems incorporating:

• Water softening
• Reverse osmosis
• Ultrafiltration
• Fine filtration
• Side-stream filtration
• Chemical dosing
• pH correction
• Cooling-water make-up treatment
• Closed-loop fill-water treatment
• Water recovery
• Treated-water storage
• Pumping and distribution
• Siemens PLC and HMI automation
• BMS and SCADA interfaces

Systems can be designed as skid-mounted, modular or containerised packages depending on the site requirements.

Design, Manufacture, Commissioning & Service

Hydra-Clear designs and manufactures water treatment systems in the UK.

Our involvement can continue throughout the complete system lifecycle:

Water Analysis → Process Design → Detailed Engineering → Manufacture → FAT → Installation → Commissioning → Handover → Service

For critical sites, planned maintenance and operational support can be incorporated into the project from the outset.

Because the engineers maintaining the equipment understand how the treatment process works, our service approach goes beyond simply changing filters and checking boxes.

Existing Data Centre?

Water optimisation does not only apply to new builds.

Existing cooling systems can often be assessed for opportunities to reduce water consumption or improve reliability.

Hydra-Clear can review:

• Incoming water chemistry
• Current pretreatment
• Cooling-tower make-up
• Cycles of concentration
• Blowdown
• RO recovery
• Softener performance
• Water consumption
• Filtration
• Storage
• Existing instrumentation
• Treatment redundancy

We can then identify where improvements are technically and commercially justified.

Start With the Water Balance

Before selecting equipment, we want to understand the complete cooling-water requirement.

For a new data centre project, useful information includes:

• Incoming water analysis
• Cooling-system design
• Maximum make-up demand
• Normal make-up demand
• Cooling tower evaporation
• Target cycles of concentration
• Blowdown requirements
• Required closed-loop water specification
• Required redundancy
• Available storage
• Future expansion
• BMS or SCADA requirements

From there, Hydra-Clear can develop the treatment philosophy around the facility.

Talk to a Data Centre Water Treatment Engineer

Whether the objective is improving cooling-water quality, reducing blowdown, producing RO make-up water, protecting a closed cooling loop or developing a site-wide water reuse strategy, the process should begin with the water chemistry and cooling design.

Reliable cooling needs reliable water.

Call 0800 999 6770 or contact Hydra-Clear to discuss your data centre water treatment requirements.