Towards Circular Economy: Managing the Lifecycle of Immersion Cooling Fluids

Author: Chris Fletcher, BP Castrol; Brandon Marshall, Commor Collection: 2024 OCP Global Summit - Cooling Environments & Immersion

Summary

This presentation reports on a newly formed OCP workstream dedicated to fluid lifecycle management — what to do with immersion cooling fluids when they reach end of usable life or when equipment is retired. Co-presented by Chris Fletcher (BP Castrol) and Brandon Marshall (Commor), the workstream was started in 2024 and is at an early stage, focused first on establishing common vocabulary and mapping the option space before writing specific guidance. The workstream charter covers four lifecycle management areas: fluid evaluation (assessing fluid quality and selecting a reuse or destruction stream), fluid removal from operation (safe handling and transport preparation), fluid transport (carrier permitting and packaging), and fluid recycling and destruction. Of these, only fluid recycling and destruction is the current active focus; fluid evaluation is planned for 2025 and fluid transport is out of scope for this workstream.

For single-phase hydrocarbon-based immersion fluids, three end-of-life options are defined in increasing order of desirability: Destruction (incineration or use as alternative fuel via a qualified hazardous waste carrier — least desirable due to highest carbon cost), Fluid Recycling (open-loop re-refining to return hydrocarbon molecules to a generic lubricant application — more desirable than destruction), and Fluid Reconditioning (closed-loop recycling: filtration to remove contaminants, drying to remove water, re-additization, and return to service in an immersion cooling application — most desirable). For two-phase fluorochemical immersion fluids, destruction options identified include traditional high-temperature incineration and plasma arc destruction, which converts materials to vitrified slag and reduces emissions by 99.9% compared to incineration. Two-phase recycling options include filtration (activated carbon, activated alumina, molecular sieve for contaminant and moisture removal) and distillation (boiling-point separation of contaminants).

A cross-cutting requirement identified by the workstream is that recycled or reconditioned fluids must meet a quality specification comparable to virgin material before they can be returned to service — and no such specification yet exists for immersion cooling fluids. The workstream points to AHRI Standard 700 (Specifications for Refrigerants) as a precedent model from the two-phase refrigerant industry, which has established analogous standards for recycled refrigerant quality. Following resolution of recycling and destruction option mapping, the workstream plans to conduct LCAs (Life Cycle Assessments) of the different disposal options, requiring input from participants with LCA expertise.