For modern hybrid and AI-driven data centres, this trade-off is increasingly restrictive.
Historically, designers have faced a compromise:
- Ethylene Glycol (EG) delivers strong thermodynamic performance and low viscosity, supporting efficient pumping and heat transfer, but introduces toxicity and environmental compliance risks.
- Propylene Glycol (PG) offers significantly lower toxicity and improved safety alignment, but typically with higher viscosity and reduced heat transfer efficiency.
Castrol ON Primary Loop DTX has been developed specifically for closed-loop data centre primary cooling systems to address this challenge. It combines the low toxicity characteristics of propylene glycol with thermodynamic and hydrodynamic performance that closely approaches ethylene glycol. This enables operators to reduce pumping penalties, maintain predictable flow behaviour and improve safety — without sacrificing cooling efficiency.
In Chiller to Chip architectures, where the same primary loop supports air cooling, direct-to-chip and immersion systems, this balanced fluid performance is critical. Glycol selection is therefore a strategic engineering decision, not a commodity purchase.
