Immersion Cooling Fluids for Bitcoin Miners — Dielectric Coolant Reference
Immersion cooling submerges a Bitcoin ASIC miner directly in a non-conductive (dielectric) fluid, which carries heat away far more effectively than air and lets a Hashcenter run quieter, denser and at lower fan power. The fluids fall into two families: single-phase synthetic hydrocarbons and mineral oils that stay liquid and are pumped to a heat exchanger, and two-phase engineered fluorinated fluids that boil right at the chip and condense above the bath.
This open reference compiles the dielectric coolants miners actually evaluate, with each fluid’s dielectric strength, viscosity, flash and boiling points, thermal conductivity, density and global-warming potential traced to the manufacturer’s own technical or safety data sheet. Download the full dataset as CSV or JSON, or query it through our open API.
Quick answer
Immersion cooling submerges an ASIC miner directly in a non-conductive (dielectric) fluid that carries heat away far more effectively than air. Two families dominate: single-phase synthetic hydrocarbons and mineral oils (for example BitCool BC-888, Shell S3 X, Castrol ON DC 20), which stay liquid and are pumped to a heat exchanger; and two-phase engineered fluorinated fluids (3M Novec, Fluorinert, Solvay Galden), which boil at a low temperature right at the chip and condense above the bath. This reference lists 12 fluids with their dielectric strength, viscosity, flash and boiling points, thermal conductivity, density and global-warming potential, each traced to the manufacturer datasheet.
Single-phase hydrocarbon fluids are the practical default for ASIC mining — high flash points (about 160-200 C), modest cost and low environmental impact. Two-phase fluorinated fluids deliver the highest heat flux but carry far higher cost and, for perfluorocarbon (FC-40) and perfluoropolyether (Galden) chemistries, very high global-warming potential; 3M has been winding down its fluorinated-fluid (PFAS) manufacturing, so long-term supply and lifecycle should factor into any two-phase design.
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| Fluid | Maker | Type | Dielectric (kV) | Visc. @40C (cSt) | Flash (°C) | Pour (°C) | Therm. cond. (W/m·K) | Density (g/cm³) | Boiling (°C) | GWP | Typical use |
|---|---|---|---|---|---|---|---|---|---|---|---|
| BitCool BC-888 | Engineered Fluids | single-phase synthetic hydrocarbon | >40 (0.1in gap) | — | 201 | -65 | 0.135 | 0.80 | — | Low (hydrocarbon) | Single-phase full immersion of ASIC miners; mining-specific formulation |
| Shell Immersion Cooling Fluid S3 X | Shell | single-phase synthetic hydrocarbon | — | 9.9 | 198 | <=-42 | — | 0.808 | — | Low (hydrocarbon) | Single-phase immersion of servers and ASIC miners; Gas-to-Liquid (GTL) base oil |
| Castrol ON Immersion Cooling Fluid DC 20 | Castrol | single-phase synthetic hydrocarbon | >35 (DIN EN 60156) | 5.1 | 159 | -75 | 0.139 | 0.797 | — | Low (hydrocarbon) | Single-phase Hashcenter / ASIC immersion; low viscosity, high specific heat |
| Technical / White Mineral Oil (representative) | Various (naphthenic / paraffinic) | single-phase mineral oil | 30-70 (dry/treated) | 12-30 | 135-200 | -30 to -60 | ~0.13 | 0.86-0.88 | — | Low (hydrocarbon) | Low-cost DIY single-phase immersion; higher viscosity and more oxidation than engineered fluids (representative ranges, not one product) |
| 3M Novec 7000 | 3M | two-phase fluorocarbon-engineered-fluid | 40 (0.1in gap) | 0.28 (at 30C) | None (non-flammable) | — | 0.072 | 1.40 | 34 | 575 | Two-phase immersion; lowest boiling point in the Novec line (evaporative cooling at the chip) |
| 3M Novec 7100 | 3M | two-phase fluorocarbon-engineered-fluid | >25 (0.1in gap) | — | None (non-flammable) | -135 | 0.069 | 1.51 | 61 | 320 | Two-phase immersion cooling of electronics and ASICs |
| 3M Novec 7200 | 3M | two-phase fluorocarbon-engineered-fluid | — | 0.43 (at 25C) | None (non-flammable) | -138 | 0.068 | 1.43 | 76 | 55 | Two-phase immersion cooling; higher boiling point than Novec 7100 |
| 3M Novec 7500 | 3M | two-phase fluorocarbon-engineered-fluid | 35 (0.1in gap) | 0.50 (at 50C) | None (non-flammable) | -100 | 0.065 | 1.60 | 128 | 90 | Single- or two-phase immersion; high boiling point suits direct-contact server cooling |
| 3M Novec 649 (fluoroketone, FK-5-1-12) | 3M | two-phase fluorocarbon-engineered-fluid | >40 (0.1in gap) | 0.40 (at 25C) | None (non-flammable) | -108 | 0.059 | 1.60 | 49 | 1 | Two-phase immersion; low-GWP fluoroketone (also marketed as a clean fire-suppression agent, Novec 1230) |
| 3M Fluorinert FC-40 | 3M | two-phase fluorocarbon-engineered-fluid | 46 (0.1in gap) | 2.2 (at 25C) | None (non-flammable) | -57 | 0.062 | 1.855 | 165 | >5000 (high; perfluorocarbon) | Two-phase immersion at high boiling point; legacy perfluorocarbon, long atmospheric lifetime |
| Galden HT-55 (PFPE) | Syensqo (Solvay) | two-phase fluorocarbon-engineered-fluid | 40 (2.5mm gap) | 0.45 (at 25C) | None (non-flammable) | -110 | 0.065 | 1.65 | 55 | High (~9000-10000; perfluoropolyether) | Two-phase immersion; lowest-boiling Galden HT grade |
| Galden HT-110 (PFPE) | Syensqo (Solvay) | two-phase fluorocarbon-engineered-fluid | 40 (2.5mm gap) | 0.77 (at 25C) | None (non-flammable) | -100 | 0.065 | 1.71 | 110 | High (~9000-10000; perfluoropolyether) | Two-phase immersion; higher-boiling Galden HT grade |
Dielectric-strength gaps differ between vendors (0.1 in vs 2.5 mm) and are not directly comparable; mineral-oil figures are representative ranges, not a single product. Sources: manufacturer technical and safety data sheets (Engineered Fluids, Shell, Castrol, 3M, Syensqo/Solvay). Related reading: immersion vs air cooling, ASIC cooling comparison, and the D-Central immersion cooling guide. See the open data hub.
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Last reviewed June 26, 2026.