Role of a Liquid Accumulator in a Passive Two-Phase Liquid Cooling System for Electronics: Experimental Analysis

2017 ◽  
Author(s):  
Nicolas Lamaison ◽  
Raffaele L. Amalfi ◽  
Jackson B. Marcinichen ◽  
John R. Thome ◽  
Todd Salamon
Keyword(s):  
Cooling System ◽  
Flow Boiling ◽  
Relative Size ◽  
Electronics Cooling ◽  
Filling Ratio ◽  
Liquid Cooling ◽  
Two Phase ◽  
Wide Range ◽  
Phase Liquid ◽  
Liquid Cooling System

Gravity-driven two-phase liquid cooling systems using flow boiling within micro-scale evaporators are becoming a game-changing solution for electronics cooling. The optimization of the system’s filling ratio can however become a challenging problem for a system operating over a wide range of cooling capacities and temperature ranges. The benefits of a liquid accumulator to overcome this difficulty are evaluated in the present paper. An experimental thermosyphon cooling system was built to cool multiple electronic components up to a power dissipation of 1800 W. A double-ended cylinder with a volume of 150 cm3 is evaluated as the liquid accumulator for two different system volumes (associated to two different condensers). Results demonstrated that the liquid accumulator provided robust thermal performance as a function of filling ratio for the entire range of heat loads tested. In addition, the present liquid accumulator was more effective for a small volume system, 599 cm3, than for a large volume system, 1169 cm3, in which the relative size of the liquid accumulator increased from 12.8 % to 25% of the total system’s volume.

Role of a Liquid Accumulator in a Passive Two-Phase Liquid Cooling System for Electronics: Experimental Analysis

2018 ◽  
Vol 140 (1) ◽  
Author(s):  
Nicolas Lamaison ◽  
Raffaele L. Amalfi ◽  
Todd Salamon ◽  
Jackson B. Marcinichen ◽  
John R. Thome
Keyword(s):  
Cooling System ◽  
Flow Boiling ◽  
Relative Size ◽  
Electronics Cooling ◽  
Liquid Cooling ◽  
Two Phase ◽  
Wide Range ◽  
Gravity Driven ◽  
Phase Liquid ◽  
Liquid Cooling System

Gravity-driven two-phase liquid cooling systems using flow boiling within microscale evaporators are becoming a game-changing solution for electronics cooling. The optimization of the system's filling ratio (FR) can however become a challenging problem for a system operating over a wide range of cooling capacities and temperature ranges. The benefits of a liquid accumulator (LA) to overcome this difficulty are evaluated in the present paper. An experimental thermosyphon cooling system was built to cool multiple electronic components up to a power dissipation of 1800 W. A double-ended cylinder with a volume of 150 cm3 is evaluated as the LA for two different system volumes (associated with two different condensers). Results demonstrated that the LA provided robust thermal performance as a function of FR for the entire range of heat loads tested. In addition, the present LA was more effective for a small volume system, 599 cm3, than for a large volume system, 1169 cm3, in which the relative size of the LA increased from 12.8% to 25% of the total system's volume.

scholarly journals The study of gas-liquid flow dynamics in the inclined-corrugated elements of cooling tower filler unit

2019 ◽  
Vol 126 ◽  
pp. 00031 ◽  
Author(s):  
lnur N. Madyshev ◽  
Aliya I. Khafizova ◽  
Oksana S. Dmitrieva
Keyword(s):  
Liquid Flow ◽  
Cooling Tower ◽  
Cooling System ◽  
Flow Dynamics ◽  
Stable Operation ◽  
Liquid Cooling ◽  
Two Phase ◽  
Liquid Drops ◽  
Gas Liquid Flow ◽  
Liquid Cooling System

This paper deals with the studies of cooling tower, operated with the contactless evaporative cooling technology. The authors developed the cooling tower with a three-flow liquid cooling system. The authors conducted the numerical studies of gas-liquid flow dynamics in the inclined-corrugated elements of checker filling unit that allows to give us an idea of two-phase flow structure, its movement throughout the checker filling, as well as to assess the influence of mode parameters on the efficiency of collecting the liquid drops and the range of stable operation of device. The most effective operation of this device is at the pressure drop of 100 Pa, while developing the average air flow rate in the element up to 3.2 m/s.

Performance of Concentrator Photovoltaic Systems Integrated With Double Layer Microchannel Heat Sink

2019 ◽  
Author(s):  
Ali Radwan ◽  
Mohamed M. Awad ◽  
Shinichi Ookawara ◽  
Mahmoud Ahmed
Keyword(s):  
Solar Cell ◽  
Double Layer ◽  
Heat Sink ◽  
Flow Boiling ◽  
Microchannel Heat Sink ◽  
Temperature Uniformity ◽  
Liquid Cooling ◽  
Cell Temperature ◽  
Wide Range ◽  
Phase Liquid

Abstract In this study, a new design of double layer microchannel heat sink (DL-MCHS) has been monolithically fabricated using 3D metal printer and experimentally examined as a heat sink for concentrator photovoltaic (CPV) systems. Single phase liquid cooling using ethanol and flow boiling cooling using NOVEC-7000 coolant in the designed DL-MCHS are experimentally compared. The results proved that using the flow boiling cooling technique for the CPV systems attained a lower solar cell temperature with high temperature uniformity. In more details, flow boiling in counterflow (CF) operated DL-MCHS, attained a very low solar cell temperature close to the NOVEC-7000 boiling point with temperature uniformity of 0.2 °C over a wide range of coolant flow rate from 25–250 ml/hr.

Experimental Validation and Design Simulations of a Passive Two-Phase Cooling System for Datacenters

2020 ◽  
Author(s):  
Jackson B. Marcinichen ◽  
John R. Thome ◽  
Raffaele L. Amalfi ◽  
Filippo Cataldo
Keyword(s):  
Thermal Performance ◽  
Experimental Validation ◽  
Cooling System ◽  
Electronics Cooling ◽  
Operating Conditions ◽  
Two Phase ◽  
Data Set ◽  
Pressure Drops ◽  
Wide Range ◽  
Important Challenge

Abstract Thermosyphon cooling systems represent the future of datacenter cooling, and electronics cooling in general, as they provide high thermal performance, reliability and energy efficiency, as well as capture the heat at high temperatures suitable for many heat reuse applications. On the other hand, the design of passive two-phase thermosyphons is extremely challenging because of the complex physics involved in the boiling and condensation processes; in particular, the most important challenge is to accurately predict the flow rate in the thermosyphon and thus the thermal performance. This paper presents an experimental validation to assess the predictive capabilities of JJ Cooling Innovation’s thermosyphon simulator against one independent data set that includes a wide range of operating conditions and system sizes, i.e. thermosyphon data for server-level cooling gathered at Nokia Bell Labs. Comparison between test data and simulated results show good agreement, confirming that the simulator accurately predicts heat transfer performance and pressure drops in each individual component of a thermosyphon cooling system (cold plate, riser, evaporator, downcomer (with no fitting parameters), and eventually a liquid accumulator) coupled with operational characteristics and flow regimes. In addition, the simulator is able to design a single loop thermosyphon (e.g. for cooling a single server’s processor), as shown in this study, but also able to model more complex cooling architectures, where many thermosyphons at server-level and rack-level have to operate in parallel (e.g. for cooling an entire server rack). This task will be performed as future work.

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