©2025 This excerpt taken from the article of the same name which appeared in ASHRAE Journal, vol. 67, No. 9, September 2025.
Liquid Cooling Cold Plates
By Dustin Demetriou and David Quirk
Dustin Demetriou, Ph.D., is chair of the ASHRAE TC 9.9 IT subcommittee. David Quirk, P.E., is president at DLB Associates.
As the information technology equipment (ITE) industry begins to transition from air- to liquid-cooled servers, the term “cold plate” has begun to infiltrate the vernacular of the HVAC community. Far from being a tasty salad dish on ice, the “cold plate” is an integral component of a liquid-cooled server. As such, this and two succeeding columns take a break from our typical focus on the facility side of data centers to focus on the server processor’s cold plate: its definition, history, design, maintenance and future trends. A better understanding of cold plates will hopefully provide insight to aid in the design of more resilient and energy efficient liquid-cooling systems.
As used in the IT industry, a “cold plate” is a heat exchanger. The cold plate is generally constructed of a metal plate with fins and channels to facilitate the removal of heat from a computer’s high heat density processors to a cooling liquid, typically pumped and forced through the channels where they absorb the heat. The cold plates in a liquid cooling technology cooling system (TCS) are roughly equivalent to the terminal units of a distributed chilled water system, but with very specific temperature, flow, pressure drop, material compatibility and cleanliness requirements.
Cold plates have been used for thermal management since the 1960s, particularly in aerospace and military applications, where air-cooling was insufficient.
The trend toward higher circuit power density in the electronics industry necessitated a switch to liquid cooling.1 IBM’s thermal conduction module is an example of direct liquid-cooled bipolar CPUs back in the 1980s. Heat was conducted across a piston-and-hat structure to a module surface where it was then conducted into a liquid-carrying cold plate. The cold plate is analogous to an air-cooled heat sink in that it has extended surfaces, or fins, with fluid carrying channels.
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