What is the Castrol ON Immersion Cooling Fluid DC 20?
DC 20 is Castrol's synthetic-hydrocarbon dielectric coolant for single-phase immersion. Its product sheet reports typical density of 797 kg/m³, kinematic viscosity of 5.1 mm²/s at 40°C, dielectric strength above 14 kV/mm, specific heat of 2.08 kJ/kg·K, and thermal conductivity of 0.135 W/m·K. Those values support pumping and heat-transfer calculations, but they do not establish immersion-tank capacity or electronics life. Castrol reports that Submer tested DC 20 and approved it across Submer equipment. Project documentation still needs to confirm the exact tank, region, warranty, and current fluid revision. Candidate fluids should be compared at the same temperatures, flow, heat load, contamination state, and safety boundary. Due diligence covers the latest safety data sheet, flash and fire controls, material and server compatibility, batch quality, moisture and particle limits, oxidation monitoring, filtration, storage, spill procedures, top-up, recovery, and disposal. The cited sheet gives no price, guaranteed service interval, or independent production-fleet results. Submer's general approval should become a project-specific document naming supported tank models, fluid revision, operating limits, and warranty owner. Acceptance records should capture delivered quantity, batch identity, cleanliness, moisture, and electrical properties before servers enter the bath, with sealed baseline samples retained. The contract also needs to define whether used fluid can be reclaimed, where it may be shipped, and who bears replacement and downtime costs after an out-of-limit result.