In today’s architectures, glycol is essential within primary cooling infrastructure exposed to ambient conditions, where freeze risk, uptime, and energy performance must all be carefully balanced.
These areas include:
- Air-cooled and hybrid chiller systems
- Dry coolers and heat rejection equipment
- Economiser / free cooling circuits
- External pipework and distribution systems
As data centres continue to adopt air-cooled and economised designs, a growing proportion of cooling infrastructure operates outside tightly controlled environments. In these conditions, glycol becomes a core enabler of reliable, year-round operation.
Why glycol is critical in primary cooling infrastructure
Any part of the cooling system exposed to low ambient temperatures is at risk of freezing. Without appropriate fluid protection, this can result in:
- Ice formation in heat exchangers
- Cracked pipework and mechanical failure
- Loss of cooling capacity
- Unplanned downtime
Even short sections of exposed pipework can become single points of failure.
For operators, glycol is therefore not just a protective measure — it is a critical component of system resilience and uptime assurance.
The real challenge: performance vs safety
While glycol is essential, fluid selection has a direct impact on energy efficiency and system performance.
Traditionally, operators have had to balance performance against safety:
Ethylene Glycol (EG) — High Performance, Higher Risk
- Excellent heat transfer and low viscosity
- Supports efficient pumping and strong system performance
However:
- Toxic to humans and harmful to the environment
- Less suitable for data centres due to safety, handling, and regulatory considerations
Propylene Glycol (PG) — Safer, but Less Efficient
- Low toxicity and widely accepted
But:
- Higher viscosity → increased pumping energy
- Lower thermal conductivity → reduced heat transfer efficiency
- Negative impact on COP and PUE
At scale, these limitations translate directly into higher energy consumption and operating cost.
Eliminating the trade-off: Castrol ON Primary Fluid DTX
Castrol On Primary Cooling Fluid DTX has been engineered to remove this compromise.
It delivers:
- The thermal and flow performance of ethylene glycol
- The low-toxicity profile of propylene glycol
Proven Performance Gains vs Propylene Glycol
- 10% increase in COP
- Comparable reductions in energy consumption and carbon emissions
- Lower viscosity → reduced pumping energy
- Improved heat transfer → enhanced PUE performance
In new system designs, this performance can also enable:
- Smaller chillers and pumps
- Reduced pipework sizing
- Lower capital expenditure
Designed for modern data centre cooling systems
Castrol On Primary Cooling Fluid DTX is specifically developed for demanding cooling environments, offering:
- Resistance to oxidation, thermal degradation, and biological contamination
- Optimised thermodynamic and hydrodynamic performance
- Compatibility with nanoparticles and advanced additives
- Low toxicity and biodegradability
- Full compatibility with system materials
- Potential for reuse or upcycling at end of life
DTX is already proven in highly demanding applications including, food and beverage process cooling, medical devices used in surgery, and advanced aerospace cooling systems.
Why fluid management matters as much as fluid selection
Selecting the right glycol is only part of the equation. In data centre cooling systems, how the fluid is monitored, maintained, and managed over time has a direct impact on efficiency, reliability, and asset life. Without a structured fluid management approach, even high-quality glycol can degrade, leading to:
- Increased viscosity and pumping energy
- Reduced heat transfer efficiency
- Corrosion, fouling, and system contamination
- Gradual loss of cooling performance and rising operational costs
These issues are often invisible in the short term, but over time can significantly impact:
- PUE and energy consumption
- Equipment lifespan
- System reliability and uptime
Castrol ON End-to-End Fluid Management Solutions are designed to ensure that cooling fluids continue to perform as intended throughout their operational life. This includes:
- Fluid condition monitoring and analysis
- Optimisation of concentration and performance
- Predictive maintenance insights
- Contamination control and system health checks
By combining high-performance fluids like DTX with proactive lifecycle management, operators can maintain consistent thermal efficiency, reduce unplanned maintenance and downtime, and extend system and fluid life
