Definition
A cold plate, also called a water block, is a sealed metal block, usually copper or aluminum, with internal channels that carry liquid coolant directly across the surface of heat-producing chips. In direct-to-chip liquid cooling it replaces the traditional finned heatsink-and-fan stack on an ASIC hashboard, transferring heat into a flowing coolant loop instead of into the surrounding air.
How it works
Coolant, typically a treated water-glycol mix with corrosion inhibitors, is pumped through micro-channels machined into the plate. It absorbs heat as it passes over the chip contact surface, then travels through tubing to an external heat exchanger or dry cooler where the energy is rejected. Because liquid carries far more heat per unit volume than air, a cold plate can keep chips cool at power densities that would overwhelm forced-air cooling, and it does so almost silently.
Operating considerations
Cold-plate loops demand clean coolant and proper metallurgy. Tap water causes galvanic corrosion between dissimilar metals, so deionized water is the starting point, and filtration is needed because particulate or biological growth can clog the narrow channels and create uneven hot spots. Compared with full immersion, direct-to-chip cold plates target only the highest-heat components, leaving the rest of the board air-cooled, which makes them a middle path between air and tank immersion.
For the fully submerged alternative and the interface that still matters under the plate, see Dielectric Fluid and Thermal Paste.
See where this fits in the cooling methods comparison.
In Simple Terms
A cold plate, also called a water block, is a sealed metal block, usually copper or aluminum, with internal channels that carry liquid coolant directly…