JJ Cooling
PHYSICS. APPLIED.
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Research / ΔT

Two-phase cooling:
models and experiments.

Our researchers study boiling, condensation and passive fluid circulation. These papers describe thermosyphon designs and compare their models with laboratory measurements.

JJ CoolingPHYSICS. APPLIED.ΔT / 01

Datacenter thermosyphon validation

ASME InterPACK · 2020

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

J. B. Marcinichen, J. R. Thome, R. L. Amalfi & F. Cataldo

JJ Cooling’s thermosyphon simulator was compared with an independent server-cooling dataset from Nokia Bell Labs. The paper reports good agreement for component heat transfer and pressure drops.

Validation against the studied dataset; parallel rack-scale architectures were identified as future work.

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JJ CoolingPHYSICS. APPLIED.ΔT / 02

CPU thermosyphon design

IEEE TCPMT · 2021

Air-Cooled Loop Thermosyphon Cooling System for High Heat Load CPUs—Part I: Design and Performance Simulation

J. B. Marcinichen, G. S. R. B. Armas, G. Rouaze, J. R. Thome & L. W. Zhang

The study simulated a compact, buoyancy-driven loop thermosyphon for high-heat-load CPUs in 2U servers, linking cooling architecture to thermal-hydraulic performance.

Design simulation, not a measured product rating. The fluid loop is passive; the air-cooled condenser still requires fan power.

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JJ CoolingPHYSICS. APPLIED.ΔT / 03

CPU thermosyphon experiments

IEEE TCPMT · 2021

Air-Cooled Loop Thermosyphon Cooling System for High Heat Load CPUs—Part II: Experimental Results and Validation

G. S. R. B. Armas, G. Rouaze, J. B. Marcinichen, J. R. Thome & L. W. Zhang

A 66 mm-high prototype was tested using two refrigerants. With R1233zd(E), the reported test range was 100–700 W; solver validation reported a mean junction-temperature error of 2.1 K and maximum error of 5.8 K.

Heated 16 cm² copper pseudo-CPU; R1233zd(E) tests used 25–30 °C inlet air and 40–178 CFM. Results apply to this prototype and test campaign, not every CPU or cooling system.

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Selected publications by our researchers.

Prototype results

Laboratory tests
and numerical designs.

Prototype tests and numerical designs, with operating conditions and sources.

REPORTED TEST

2.8kW

Tested PHP prototype

Architecture
Aluminum pulsating heat pipe
Device temperature
85 °C
Conditions & source

An aluminum pulsating heat pipe for power electronics was fabricated and tested. JJ Cooling reports an 85 °C device temperature and cooling-water conditions of 40 °C / 20 °C.

Historical prototype result—not a tested 5 kW AI-chip cold plate. The available test summary does not map each water condition to a separate operating point.

JJ Cooling · Company-reported test result. Not an independently published product rating.

REPORTED TEST

340W/cm²

Pumped two-phase research

Architecture
Pumped two-phase
Metric boundary
Local research heat flux
Conditions & source

JJ Cooling reports pumped two-phase cooling research tests reaching 340 W/cm². This is an active-flow architecture, distinct from passive pulsating heat pipes.

Local research-test heat flux—not a full-chip power rating. Detailed geometry, coolant and test protocols require technical review.

JJ Cooling · Company-reported test result. Not an independently published product rating.

NUMERICAL DESIGN

5kW

Cold-plate simulation

Architecture
Multilayer cold-plate concept
Validation gate
Prototype testing remains
Conditions & source

A multilayer cold-plate concept has been numerically evaluated for thermal duty, temperature, pressure losses and flow distribution.

Simulation only. No 5 kW prototype qualification or chip junction-temperature tests are reported; prototype testing remains to be done.

JJ Cooling · Company-reported numerical design. Not an independently published product rating.

Additional laboratory result

Additional company-reported PHP result: 0.021 °C/W thermal resistance. Operating conditions and measurement boundaries are not supplied; this is not a universal system specification.

The next step

Discuss your project
with our engineers.

Tell us what you are building and where you need help.

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