Experimental Testing & Thermal-Hydraulic Characterization
Independent testing, optimization, and validation of cooling technologies — from single components to complete cooling systems.
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JJ Cooling provides advanced experimental facilities to characterize, validate, and optimize thermal management technologies.
Our laboratories enable independent testing of cooling components and complete cooling systems under controlled operating conditions, allowing accurate measurement of thermal-hydraulic performance.
From early-stage prototypes to final product validation, our facilities help companies:
• Measure real thermal performance
• Optimize cooling system operation
• Validate new cooling technologies
• Reduce development risks
• Accelerate time-to-market
• Thermal-hydraulic performance characterization
• Cooling system validation and benchmarking
• Working fluid and fluid charge optimization
• Heat load and operating envelope testing
• Experimental validation of thermal models
• Independent third-party testing
Our facilities support testing and validation of a wide range of cooling technologies, from individual components to complete thermal systems.
Cooling Components
• Heat exchangers
• Microchannel heat exchangers
• Condensers and evaporators
• Cold plates
• Passive cooling devices (heat pipes, thermosyphons, pulsating heat pipes)
• Cooling manifolds and flow distribution systems
• Liquid cooling components
Complete Cooling Systems
We also test complete cooling architectures, including:
• Passive cooling systems
• Air-cooled systems
• Liquid-cooled systems
• Two-phase cooling loops
• Hybrid cooling architectures
Testing complete systems allows evaluation of:
• Overall thermal performance
• System stability
• Operational limits
• Optimization of operating conditions
Our laboratories enable comprehensive thermal-hydraulic characterization of cooling technologies.
We measure and analyze:
• Heat transfer performance
• Thermal resistance
• Heat transport capacity
• Temperature distribution
• System efficiency
Modern electronics such as AI accelerators, GPUs, CPUs, and power electronics often generate strongly non-uniform heat loads with localized hot spots and rapid power fluctuations.
JJ Cooling provides experimental capabilities to reproduce and measure these realistic thermal conditions, enabling accurate evaluation of cooling technologies under dynamic and spatially non-uniform heat loads.
Our testing approach allows controlled simulation of hot-spot heat generation and transient thermal loads, similar to those encountered in high-performance computing and advanced semiconductor systems.
Capabilities include:
• Hot-spot heat flux testing using localized heating elements
• Transient thermal response characterization
• Evaluation of cooling performance under dynamic power loads
• Temperature uniformity analysis across heated surfaces
• Identification of thermal bottlenecks in cooling architectures
• Validation of cold-plate and heat-spreader designs
These capabilities are particularly valuable for development of cooling solutions for:
• Artificial Intelligence processors
• GPUs and CPUs
• High-performance computing (HPC) systems
• Power electronics
• Data-center hardware
• Advanced semiconductor and photonics systems
By reproducing realistic heat-load conditions, JJ Cooling helps clients design, validate, and optimize cold plates and advanced cooling systems before full product integration.
Hydraulic measurements include:
• Pressure drop characterization
• Flow distribution analysis
• Mass flow measurements
• Two-phase flow behavior
Our facilities allow iterative testing and optimizationduring product development.
Typical studies include:
• Working fluid selection
• Fluid charge optimization
• Flow rate optimization
• Heat load testing
• Operating envelope characterization
• Design validation and troubleshooting
JJ Cooling operates several dedicated experimental facilities for thermal-hydraulic testing and validation of cooling technologies.
These facilities support both component-level characterization and full system validation, from early-stage prototypes to industrial product development.
JJ Cooling operates more than seven dedicated experimental facilities covering passive cooling, liquid cooling, and two-phase thermal management technologies.
This pilot demonstrator showcases passive two-phase cooling technologies for high-power electronics such as CPUs and GPUs.
The demonstrator integrates loop thermosyphons and pulsating heat pipes and enables evaluation of different working fluids and operating conditions.
Capabilities include:
• Demonstration of passive cooling solutions for electronics
• Evaluation of loop thermosyphon performance
• Pulsating heat pipe testing and comparison
• Working fluid selection and optimization
• Validation of passive cooling architectures for high-power processors
This facility provides a realistic platform for demonstrating advanced passive cooling technologies to industrial partners.
The FAST thermal testing facility enables rapid evaluation of cooling solutions using transient thermal response analysis.
Compared with conventional full-characterization setups, this approach allows significantly faster installation, reduced testing cost, and simplified experimental configuration.
Key advantages include:
• Rapid installation and testing setup
• Extraction of high-value thermal performance metrics from transient thermal response
• Minimal experimental preparation (thermal paste and Kapton interface)
• Elimination of complex external cooling circuits and large thermal baths
• Improved operational safety by applying temperature-controlled boundary conditions
• Avoidance of dry-out phenomena during testing
This methodology enables fast screening and benchmarking of cooling technologies while maintaining reliable performance evaluation.
Heat capacity: up to ~5 kW
The Universal Test Section Experimental Facility is a versatile platform for thermal-hydraulic characterization of cooling components and systems.
Capabilities include:
• Wind tunnel for air-side thermal testing
• Passive cooling system characterization
• Active liquid cooling testing
• Single-phase and two-phase heat transfer studies
• Microchannel heat exchanger testing
Typical applications include:
• Electronics cooling
• Air-cooled heat exchangers
• Compact thermal systems
Heat transfer capacity: up to ~5 kW
JJ Cooling operates several rigs dedicated to the characterization of passive two-phase cooling technologies, including:
• Pumped refrigerant loops
• Vapor quality control
• Mass flow measurement using Coriolis flow meters
• Heat transfer performance analysis
Typical applications include:
• Evaporator testing
• Condenser characterization
• Two-phase flow analysis
• Thermal stability evaluation
Heat transfer capacity: up to ~5 kW
JJ Cooling operates several rigs dedicated to the characterization of passive two-phase cooling technologies, including:
• Thermosyphons
• Pulsating heat pipes
• Passive two-phase cooling loops
Capabilities include:
• Heat transport capacity measurement
• Working fluid charge optimization
• Start-up and stability characterization
• Long-duration performance testing
These facilities support development of high-efficiency passive cooling technologies for electronics and industrial applications.
Heat transfer capacity: up to ~5 kW (higher values possible depending on configuration)
This facility enables testing of cooling components under high heat loads and controlled operating conditions.
Capabilities include:
• High heat-flux testing
• Controlled thermal baths
• Flow monitoring and measurement
• Thermal resistance evaluation
Mobile and adaptable experimental facility designed for the thermal-hydraulic characterization of closed-loop passive two-phase cooling systems and water-cooled heat exchangers.
The platform allows flexible configuration to evaluate low-power passive cooling technologies under controlled operating conditions.
Capabilities
• Thermal-hydraulic characterization of closed-loop passive cooling systems
• Performance evaluation of water-cooled heat exchangers
• Heat transport capacity measurement
• System performance mapping and characteristic curve generation
• Flexible experimental configurations for different cooling architectures
Precision test bench designed for thermal interface material (TIM) characterization and testing of compact heat exchangers used in electronics cooling applications.
The facility allows controlled measurements of thermal performance and hydraulic behavior under single-phase cooling conditions.
Capabilities
• TIM thermal resistance characterization
• Single-phase thermal-hydraulic characterization
• Performance testing of small heat exchangers and cold plates
• Evaluation of cooling solutions for electronic components
The Working Fluid Charge Experimental Facility is a dedicated station designed for the precise, safe, and repeatable charging of cooling systems with working fluids (refrigerants).
The facility enables accurate control of the working fluid charge in passive two-phase cooling systems, heat pipes, thermosyphons, and closed-loop cooling devices, ensuring optimal system performance and repeatable experimental conditions.
The charging process follows a standardized procedure including vacuum preparation, precise gravimetric charging, and final verification, allowing accurate control of the fluid mass within tight tolerances.
Key Capabilities
• Precise gravimetric charging of working fluids
• Vacuum preparation of cooling systems (down to ~0.5 mbar)
• Controlled refrigerant filling with ±2% charge accuracy
• Safe handling of working fluids
• Repeatable preparation of experimental test samples
• Optimization of working fluid charge for passive cooling systems
Typical Applications
• Heat pipes
• Loop thermosyphons
• Closed-loop passive cooling systems
• Two-phase cooling loops
• Refrigerant-based thermal systems
Advantages for Experimental Testing
• Accurate and repeatable working fluid charge
• Faster preparation of experimental test campaigns
• Reduced working fluid losses
• Safe handling of refrigerants
• Improved reliability of thermal performance testing
To ensure accurate characterization, our laboratories are equipped with advanced instrumentation and diagnostic tools, including:
• Infrared thermography for temperature mapping
• High-precision flow meters
• Pressure sensors
• Temperature sensor arrays
• Climatic chamber for controlled ambient conditions
• X-ray inspection for non-destructive internal analysis
• Helium leak testing experimental facility for leak detection and system integrity verification
These tools enable high-accuracy measurements and detailed diagnostics of cooling systems and thermal components.
JJ Cooling operates an internal workshop to support rapid prototyping and preparation of experimental testing campaigns.
Available equipment includes:
• Precision milling machines
• Sawing and cutting machines
• Turning and machining tools
• Prototype modification and preparation tools
• 3D printer plastic machine
This infrastructure enables fast iteration between design, prototyping, and experimental validation.
Beyond experimental testing, JJ Cooling provides thermal engineering expertise to support development of advanced cooling technologies.
Our services include:
• Cooling system design
• Thermal simulation and modeling
• Test campaign definition
• Data analysis and interpretation
• Performance improvement recommendations
By combining advanced experimental facilities with strong thermal engineering expertise, JJ Cooling supports clients throughout the full product development process.
Our facilities support a wide range of industrial and research development programs.
Examples include:
• Validation of new heat exchanger designs
• Characterization of compact cooling devices
• Performance benchmarking of cooling technologies
• Optimization of passive two-phase cooling loops
• Experimental validation of thermal models
JJ Cooling provides a unique combination of:
• Advanced experimental testing infrastructure
• Deep expertise in thermal management technologies
• Experience with both passive and active cooling systems
Our laboratories support:
• Research and development programs
• Prototype validation
• Industrial product development
• Independent performance testing
JJ Cooling offers specialized experimental testing services to support the development and validation of advanced cooling technologies.
Our laboratories support both component-level characterization and full cooling system evaluation, helping companies improve performance and reduce development risks.
Experimental characterization of thermal performance under controlled operating conditions.
Typical measurements include:
• Heat transfer performance
• Thermal resistance
• Temperature distribution
• Heat transport capacity
• System efficiency
Typical applications include:
• Heat exchangers
• Cold plates
• Electronics cooling devices
• Passive cooling systems
Validation of cooling systems to confirm performance before product deployment.
Testing activities include:
• Performance verification
• Operating envelope characterization
• System stability analysis
• Start-up behavior testing
• Long-duration reliability testing
This service is particularly valuable for prototype validation and product qualification.
Comprehensive measurement of both thermal and hydraulic behavior.
Capabilities include:
• Pressure drop measurements
• Flow distribution analysis
• Mass flow characterization
• Two-phase flow analysis
These measurements provide a detailed understanding of system efficiency and design limitations.
Experimental campaigns aimed at improving cooling system performance.
Typical optimization studies include:
• Working fluid selection
• Fluid charge optimization
• Flow rate optimization
• Heat load optimization
• System design improvements
This service helps clients increase cooling efficiency and reduce energy consumption.
JJ Cooling provides independent third-party testing for comparison and validation of cooling technologies.
Typical use cases include:
• Benchmarking competing cooling technologies
• Validation of supplier performance claims
• Experimental verification of thermal models
Independent testing increases technical credibility and decision confidence.
1️⃣ Initial technical discussion
2️⃣ Definition of test objectives
3️⃣ Preparation of experimental setup
4️⃣ Experimental testing campaign
5️⃣ Data analysis and reporting
6️⃣ Engineering recommendations
If you are developing a cooling technology or need independent experimental validation, our team will be happy to discuss how JJ Cooling can support your project.
Talk to a Cooling Engineer
EPFL Innovation Park
Building A
CH-1015 Lausanne
Switzerland
Email: info@jjcooling.com
Phone: +41 21 566 10 79
