MuSEP Porous Coating for Immersion Cooling Dry-Out Limits
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Solution Overview
Problem
Traditional air-cooled fin heat sinks with heat pipes face limitations in high-power electronic devices due to high thermal resistance and early dry-out, which restrict their use in modern CPUs and GPUs, especially with heat fluxes exceeding 27 W/cm².
Innovation Solution
A multi-scale electroplated porous (MuSEP) coating is applied to heat transport surfaces, featuring a gradient in pore size and porosity, with larger pores at the top for wicking and nucleation sites, enhancing boiling efficiency and heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional air-cooled fin heat sinks with heat pipes are used, then cooling is adequate at low power, but thermal resistance increases and dry-out occurs at high power levels
Solution Approach 1:
The patent applies a porous coating on the heat transport surface to enable pool boiling heat transfer. The porous structure increases the surface area and provides nucleation sites for bubble formation, significantly enhancing heat transfer coefficients and delaying critical heat flux and dry-out conditions that limit traditional smooth-surface heat sinks at high power levels.
Solution Approach 2:
The patent utilizes phase transition of the cooling liquid from liquid to vapor through pool boiling on the porous-coated heat transport surface. This phase change process absorbs large amounts of latent heat, enabling effective heat removal at high power densities where conventional single-phase cooling becomes insufficient.
2Power
If pool boiling is implemented on a standard copper IHS coated with nickel, then cooling capacity increases, but critical heat flux remains limited at only 8.6 W/cm²
Solution Approach 1:
The patent applies a porous coating on the heat transport surface to enable pool boiling heat transfer. The porous structure increases the surface area and provides nucleation sites for bubble formation, significantly enhancing heat transfer coefficients and delaying critical heat flux and dry-out conditions that limit traditional smooth-surface heat sinks at high power levels.
Solution Approach 2:
The porous coating is applied in advance to the heat transport surface to prepare nucleation sites and enhance wicking action before operation. This preliminary modification ensures that when high power levels are reached, the surface is already optimized for efficient bubble formation and liquid replenishment, delaying the onset of critical heat flux conditions.
3Reliability
If a porous coating is applied to enhance boiling, then heat transfer improves, but manufacturing complexity increases
Solution Approach 1:
The patent employs electroplating parameters (current density, plating time, bath composition) to control the pore size distribution, porosity, and grain structure of the coating. By adjusting these parameters, the desired porous morphology for optimal boiling performance is achieved while maintaining a relatively simple manufacturing process.
Solution Approach 2:
The patent replaces complex mechanical or chemical etching processes with electroplating to create the porous structure. The electroplating process naturally forms a porous morphology through controlled deposition, eliminating the need for subsequent mechanical machining or chemical treatment steps that would increase manufacturing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The MuSEP coating significantly improves thermal performance by delaying critical heat flux and reducing thermal resistance, achieving superior heat transfer coefficients and lower junction temperatures, particularly effective in immersion cooling systems.
Implementation Method 1
the plurality of grains of second average size defining a liquid wicking structure to draw cooling liquid toward the pores
Implementation Method 2
a process for manufacturing the coating comprising: contacting a heat transport surface of a data processor with a composition including a metallic material, and electroplating the composition to obtain the coating
Data Source
AI summary
Traditional air cooled fin heat sinks, which contain heat pipes, are generally able to evacuate the heat adequately from electronic devices at low power. However, some restrictions like a high thermal resistance at high powers and an early dry-out limit their usage in new generations of CPU and GPU. The present disclosure relates to a porous coating capable of increasing the thermal performance of data processors. The coating can be applied to after-market off-the-shelf processors and increase the thermal performance in pool boiling applications. The coating can be a multi-scale electroplated porous (MuSEP) coating that increases boiling efficiency.