Application of the Trident™ Thermal Conductivity Instrument and its High-Pressure Cell accessories to measure the thermal properties of pressure-sensitive barocaloric materials before and after their phase transition.
By Ethan Garnier, Product Manager
Introduction
As interest in solid-state cooling technologies continues to grow, barocaloric materials have emerged as promising alternatives to conventional refrigerants. These materials exhibit significant thermal responses under pressure, often via pressure-induced phase transitions that dramatically alter their structure, entropy, and thermophysical properties. Understanding how thermal conductivity changes before and after these transitions is critical for evaluating device performance, heat-transfer efficiency, and refrigeration cycle design. Barocaloric effects are typically strongest near pressure-driven phase transitions, making thermal property characterization under controlled pressure conditions essential.
The Trident™ Thermal Conductivity Instrument provides a unique platform for investigating these materials under realistic operating conditions. By combining multiple transient measurement techniques with dedicated high-pressure cell accessories, researchers can examine how thermal transport evolves as a material transitions between phases.
Why Thermal Conductivity Matters
Most barocaloric research focuses on entropy changes, adiabatic temperature shifts, and phase-transition pressures. However, thermal conductivity plays an equally important role. A material may exhibit a large barocaloric effect, but poor thermal conductivity can limit the rate at which it absorbs or rejects heat during a cooling cycle.
Measuring thermal conductivity before and after a pressure-induced phase transition provides insight into:
- Heat exchanger design requirements
- Cooling cycle efficiency
- Phase-transition reversibility
In many barocaloric systems, changes in crystal structure, density, molecular ordering, or defect populations can significantly alter heat transport pathways. Capturing these changes requires measurements under the same pressure conditions that induce the transition.
High-Pressure Characterization with Trident™
The Trident™ platform offers high-pressure testing capabilities across several sensor technologies. Dedicated high-pressure cells support pressures up to 2000 PSI for MTPS measurements, 3000 PSI for TLS measurements, and 5000 PSI for TPS measurements. The TPS and TLS high-pressure cells are also compatible with hydrogen-containing environments, enabling advanced energy and refrigeration research.
This flexibility allows researchers to select the most appropriate measurement approach based on sample geometry, phase-transition behavior, and material state.
TPS: Comprehensive Bulk Property Evaluation
The Transient Plane Source (TPS) technique is particularly valuable for solid barocaloric materials because it directly measures both thermal conductivity and thermal diffusivity. The sensor is positioned between two portions of the sample, creating a well-defined heat flow environment. TPS is especially useful for bulk specimens, anisotropic materials, and novel material formats.
For barocaloric studies, a researcher can measure a material in its low-pressure phase, incrementally increase the pressure through the transition region, and compare the results with those in the high-pressure phase. Changes in conductivity and diffusivity may reveal how crystal ordering, lattice compaction, or molecular rearrangement influences heat transport.
MTPS: Fast Screening of Phase-Dependent Conductivity
The Modified Transient Plane Source (MTPS) method offers extremely rapid measurements, often in just a few seconds, making it ideal for screening large numbers of pressure and temperature conditions. MTPS directly measures thermal conductivity and thermal effusivity and accommodates a wide range of materials, including low-conductivity solids and composites.
For researchers exploring new barocaloric compositions, MTPS can quickly identify conductivity shifts associated with phase transitions before more detailed investigations are performed.
TLS: High-Pressure Testing for Powders, Slurries, and Soft Materials
Not all barocaloric materials are dense monolithic solids. Some may be available as powders, granular materials, pastes, or soft formulations. The Transient Line Source (TLS) sensor is designed for these challenging sample types and supports pressures up to 3000 PSI within Trident’s high-pressure testing configuration.
TLS enables researchers to characterize thermal conductivity across pressure-induced transformations while maintaining representative sample conditions, making it especially useful for emerging formulations.
Results from Literature
Researchers from Spain, Norway, and France successfully measured a novel solid-state thermomaterial that presents very large thermal and caloric properties of interest for barocaloric refrigeration using the C-Therm Trident™ Thermal Conductivity Instrument. Their thermomaterial demonstrated a thermal conductivity of 0.3 W·m-1·K-1 when measured using the Trident’s TPS method. These results are available in the researchers’ open-access research article at the following link [https://doi.org/10.1039/d6qi00156d].
Accelerating Barocaloric Innovation
As solid-state cooling approaches commercial deployment, understanding thermal transport across pressure-driven phase transitions will become increasingly important. By combining TPS, MTPS, and TLS measurement technologies with dedicated high-pressure cells, the Trident™ Thermal Conductivity Instrument provides researchers with a powerful toolkit to quantify how thermal conductivity, diffusivity, and effusivity evolve under pressure.
The result is a deeper understanding of barocaloric materials, enabling better material selection, improved cooling system design, and faster development of next-generation sustainable refrigeration technologies.
About Us:
C-Therm Technologies Ltd. is the global leader in thermal conductivity testing instrumentation. Headquartered in Fredericton, New Brunswick, Canada, C-Therm specializes in non-destructive thermal analysis solutions that empower researchers, manufacturers, and quality control professionals across a wide range of industries, from aerospace and automotive to textiles, electronics, and energy storage.
If C-Therm’s patented technology on the MTPS and the single-sided TPS sensors are of interest to you or any other sensor configurations (FLEX TPS, TLS, THW), feel free to contact us, or request a FREE quote below.
Email: info@ctherm.com
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Ethan Garnier is C-Therm’s Product Manager. He has extensive experience in thermal modelling and instrumentation design. He holds an MSc in Electrical Engineering and a BSc in Software Engineering from the University of New Brunswick, Canada.
References
[1] P. Dafonte-Rodríguez, Á. Ferradanes Martínez, J. Walker, J. Garcia Ben, C. J. McMonagle, S. Castro-Garcia, M. A. Señarís-Rodríguez, M. Sánchez-Andújar and J. M. Bermúdez-García, “Simple and low-cost ionic plastic crystal for multipurpose cold storage and barocaloric thermal management,” Inorg. Chem. Front., 2026, 13, 4419–4431. https://doi.org/10.1039/d6qi00156d