Definition
A dielectric fluid is a coolant that does not conduct electricity, which is precisely what lets you submerge live electronics in it. Because the fluid is non-conductive and chemically inert toward the components, an entire ASIC miner or server can sit fully immersed and run normally while the fluid carries heat away from every surface at once. This is the basis of immersion cooling.
Single-phase vs two-phase
In single-phase immersion the fluid stays liquid throughout, and pumps move warm fluid to a heat exchanger and return it cooled. These fluids are typically synthetic or mineral-based oils. In two-phase immersion the fluid is engineered to boil at a low temperature right at the hot components; the vapour rises, condenses on a cooled coil above, and rains back down, moving large amounts of heat with very little pumping power and giving exceptionally uniform chip temperatures.
Why miners use it
Immersion in dielectric fluid lets ASIC miners run at higher power and hashrate than air can safely support, while contacting every component evenly. It eliminates fan noise and dust ingestion, can extend hardware life, and captures heat in a hot liquid that is easy to reuse. The trade-offs are fluid cost, the need for compatible gaskets and seals, fluid handling and disposal, and reduced serviceability since boards must be drained before maintenance.
The fluid is circulated and temperature-controlled by a Coolant Distribution Unit (CDU), which hands the captured heat to the facility loop. For the air-side equivalent, see CFM (airflow).
In Simple Terms
A dielectric fluid is a coolant that does not conduct electricity, which is precisely what lets you submerge live electronics in it. Because the fluid…