How Stainless Steel is a Necessity for Cooling Systems in Data Centers
Abstract
Data centers rely on glycol-based liquid cooling systems to maintain operational stability in high-density computing environments. While glycol mixtures are effective, their degradation produces organic acids that can corrode vulnerable metals. Stainless steel provides unmatched resistance to these chemical processes, safeguarding system reliability. This article explores stainless steel’s necessity for data center cooling systems, with an emphasis on glycol chemistry, corrosion pathways in alternative metals, and industry standards (ASTM, ASHRAE) that underscore stainless steel’s critical role.
Introduction
The escalating energy density of modern data centers has increased reliance on liquid cooling, particularly glycol-water mixtures. These solutions provide freeze protection, microbial resistance, and stable thermal performance, but they introduce chemical challenges that make material selection mission critical. While some metals degrade rapidly in glycol systems, stainless steel maintains structural and chemical integrity, ensuring system uptime.
Glycol Mixtures in Cooling Systems
Ethylene glycol (EG) and propylene glycol (PG) mixtures, usually at 30–50% concentrations with water, are the most common coolants in data center environments. Both serve as antifreeze agents, lower freezing points, and provide stable thermal transfer. However, glycol degrades when exposed to heat and oxygen, producing organic acids including formic, glycolic, and oxalic acids. These acids reduce pH, attack system metals, and compromise coolant stability.
The ASHRAE Thermal Guidelines for Liquid Cooling of Data Processing Environments (2014) explicitly caution that material compatibility must be considered in coolant loop design. Glycol breakdown without corrosion inhibitors leads to cascading failures, particularly in systems built with carbon steel, copper, or aluminum.
Corrosion Reactions in Non-Stainless Systems
Carbon Steel: Acidic glycol reacts with iron to form iron oxides (rust). ASTM D1384 corrosion testing shows carbon steel specimens exhibit significant weight loss in inhibited glycol solutions when passivation is incomplete. The release of iron ions further destabilizes coolant chemistry.
Copper: Glycol degradation accelerates copper corrosion, producing cuprous and cupric oxides. These oxides precipitate into the fluid, fouling pumps and narrowing channels in heat exchangers.
Aluminum: Organic acids attack aluminum aggressively, forming aluminum oxide and releasing hydrogen gas. Hydrogen accumulation creates vapor lock, reducing coolant circulation and risking pump cavitation.
The net result is reduced heat transfer efficiency, increased maintenance requirements, and elevated risk of catastrophic failure in mission-critical environments.
Why Stainless Steel Is Essential
Stainless steel resists these corrosive pathways through its self-healing chromium oxide passivation layer, which remains chemically inert even in acidic glycol environments. Unlike other metals, stainless steel does not leach ions into solution, preserving coolant stability and minimizing additive consumption.
ASHRAE guidelines endorse stainless steel for liquid cooling loops where long service life and minimal maintenance are required. Stainless steel’s performance in ASTM D1384 standardized corrosion tests demonstrates negligible weight loss, confirming its superior resistance to glycol degradation compared to carbon steel or copper.
Furthermore, stainless steel’s smooth interior surfaces inhibit deposit formation and microbial colonization, reducing the need for biocidal additives. This extends coolant life cycles, lowers operational costs, and supports sustainability initiatives by reducing chemical waste.
Conclusion
Glycol-based cooling systems are indispensable in data centers, but their chemistry creates corrosive conditions that degrade carbon steel, copper, and aluminum. Stainless steel disrupts this cycle, maintaining chemical stability, structural reliability, and thermal efficiency. Backed by ASTM D1384 corrosion testing and ASHRAE liquid cooling guidelines, stainless steel is not merely an option—it is the foundation for long-term reliability in data center cooling.
References
ASTM International. ASTM D1384 – Standard Test Method for Corrosion Test for Engine Coolants in Glassware. West Conshohocken, PA.
ASHRAE. Thermal Guidelines for Liquid Cooling of Data Processing Environments. 2nd Edition. Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers, 2014.