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Capillary-Driven Boiling and Adsorptive Water Harvesting : = Enhancing Water and Energy Efficiency in Data Center Cooling.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Capillary-Driven Boiling and Adsorptive Water Harvesting :/
Reminder of title:	Enhancing Water and Energy Efficiency in Data Center Cooling.
Author:	Qianying Wu.
Description:	1 online resource (159 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 85-11, Section: B.
Contained By:	Dissertations Abstracts International85-11B.
Subject:	Energy. -
Online resource:	click for full text (PQDT)
ISBN:	9798382230153

Capillary-Driven Boiling and Adsorptive Water Harvesting : = Enhancing Water and Energy Efficiency in Data Center Cooling.
Qianying Wu.

Capillary-Driven Boiling and Adsorptive Water Harvesting :Enhancing Water and Energy Efficiency in Data Center Cooling. - 1 online resource (159 pages)

Source: Dissertations Abstracts International, Volume: 85-11, Section: B.

Thesis (Ph.D.)--Stanford University, 2024.

Includes bibliographical references

The performance and reliability of high-density microelectronics systems, crucial for data center applications, heavily rely on efficient cooling solutions to maintain low junction temperatures. Capillary-driven two-phase µ-coolers utilize capillary pressure in thin microporous materials for constant coolant replenishment. Capillary-driven boiling enables the efficient removal of high heat fluxes ranging from 0.5-1 kW/cm2 at low superheat levels of approximately 10 ◦C. The pumping-free operation and self-regulating features, responsive to real-time heat flux patterns, make capillary-driven two-phase µ-coolers particularly attractive for data center computing workloads, contributing to significant energy savings.This dissertation focuses on studying transport behaviors in capillary-driven boiling phenomena, developing µ-coolers with three-dimensional manifolding for significant size scale-up, and exploring a kinetically-enhanced adsorptive water harvester that synergistically integrates with evaporative µ-coolers. This research not only addresses the cooling challenges in data centers but also aligns with the broader goal of reducing energy and water consumption for a positive environmental impact. First, we discuss the development of graded and random-packed copper inverse opals (CIO) as promising wick materials with low thermal resistance due to their thin thickness and favorable scaling of fluid permeability with the neck-to-pore ratio. Semi-analytical models are developed to correlate the critical heat flux with the wick micro-structures based on thermal and fluid transport. A novel suspended micro-bridge measurement substrate is developed, allowing precise geometric definition of the wicking distance on thermal test substrates designed for confined heat input and thermal measurements. Investigations are carried out on steady-state boiling, determination of critical heat flux, and transient thermal and fluid properties of capillary-driven boiling in relation to bubble generation, growth, and collapse. Temperature fluctuations in capillary-driven boiling are observed to increase with higher heat flux, yet remains remarkably small compared to microchannel flow boiling. Next, we develop embedded evaporative two-phase capillary-driven µ-coolers for large-area (>0.25mm2 ) chip-scale cooling of semiconductor devices generating high heat fluxes of 0.5-1 kW/cm2 . By developing fabrication techniques allowing the deposition of large-area random-packed CIO thin films as the wicking material on the backside of the silicon substrate and bonding a three-dimensional silicon-based manifold on the surface of the wicking material, we demonstrate high critical heat fluxes at minimum flow rates, overcoming the material-intrinsic trade-off between high critical heat flux and large wicking distance. This breakthrough not only enhances cooling efficiency but also reduces energy consumption. The relationship between wick structures, manifold geometries, and flow rates with critical heat fluxes is elucidated through a theoretical model, enabling optimized µ-cooler design that minimizes energy usage. Additionally, we analyze the effect of chip size, heat flux, and flow rate on the resulting temperature profile of the electronics to be cooled, providing insights into energy-efficient cooling strategies.Finally, to enhance energy and water savings in data centers, we study the adsorption and desorption of fluidized metal-organic frameworks-303 (MOF-303) for atmospheric water harvesting by using low-grade waste heat. This system can be strategically integrated into data centers where waste heat generation and additional water supply benefit the two-phase cooling processes. By utilizing waste heat for water harvesting, this research not only contributes to water conservation but also aligns with the energy-saving objectives of data centers. We explore how kinetic enhancement affects the adsorption and desorption in fluidized MOFs under varying flow rates, heat inputs, and humidity, leading to an understanding of inter-crystalline and intra-crystalline moisture transport by comparing to packed MOFs. Fluidized MOFs achieve significantly higher water production rates, highlighting the potential for promoting energy and water savings in data center operations.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9798382230153Subjects--Topical Terms:

784773
Energy.
Subjects--Index Terms:

Coolant replenishmentIndex Terms--Genre/Form:

554714
Electronic books.

Capillary-Driven Boiling and Adsorptive Water Harvesting : = Enhancing Water and Energy Efficiency in Data Center Cooling.
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