Phase Change Matters

The lab folks at PureTemp have had a keen interest in the T-history method since our days as a tech startup with a small budget. T-history is a relatively simple, low-cost way to determine the heat of fusion, specific heat and thermal conductivity of phase change materials.

New research on the topic turned up in one of our automated searches earlier this month: “Characterizing phase change materials using the T-History method: On the factors influencing the accuracy and precision of the enthalpy-temperature curve.” The lead author, Pepe Tan, is a pursuing a Ph.D. at Chalmers University of Technology in Sweden. I contacted him to find out more. 

Q: What prompted your interest in studying the T-history method?

A: “When I started my Ph.D. at Chalmers, T-history was a good complement to the available DSC instrument in our research group. And it was a nice opportunity to collaborate with ZAE Bayern and learn the method. While implementing the method, we found it was very worth studying certain aspects of it in parallel, because of how different the method has been presented so far in the scientific community.”

Q: Do you envision T-history replacing DSC for characterizing and validating PCMs as an industry standard? If not for PCM validation, perhaps for application engineering and thermal modeling?

A: “I definitely consider T-history and DSC as complementary methods since their limitations for finding the intrinsic PCMs properties are still subject to research. With this uncertainty, any measurement available from different sources would be useful for the engineer to carefully estimate the actual behavior of the PCM in its application.”   

Q: When do you believe T-history will be studied and validated sufficiently to become adopted as a commercially available piece of equipment?

A: “To reach that goal, a systematic assessment of different implementations of the method (setup and data evaluation) would be necessary. But spending this effort also depends on the current needs for accurate PCM properties in typical applications.”

Q: Will the mathematical model of the method become open-source and available for laboratories?

A: “The data evaluation method in the paper should be seen as one proposal on how to calculate the enthalpy from real experimental data. And it is presented in detail, so that it can be recreated.

“The challenge in our experiments was to negate the noise amplification when differentiating the temperature over time data. But this could be done in many different ways, which will in turn affect the enthalpy results. We made the raw experimental data available so that other data evaluation methods can be tested.”

Q: What do you view as the most significant challenge with T-history? How does this compare to the challenges associated with DSC?

A: “That would be to perform a rigorous measurement uncertainty analysis in order to specify a reliable limit for accuracy and precision in terms of an uncertainty. Since this strongly depends on the individual implementation of the method and the chosen data evaluation, the DSC is in my opinion one step ahead.”

Q: Is T-history capable of accurate and precise measurement with thermal conductivity additives or nucleating agents?

A: “This depends on the material and the actual implementation of the method. And this would be an example where the possibility to use complementary methods that utilize different sample sizes like DSC and T-history will be helpful to filter out the intrinsic material behavior. The larger sample sizes of the T-history setup should increase the chance to actually have representative samples, meaning samples containing a representative amount of the nucleating agent and/or the thermal conductivity additives."  

Q: What are your postdoctoral plans?

A: “I expect to graduate by June 2020. At the moment, I plan to wait and see what options are available when the graduation date comes a bit closer.”

• Fabrication of shape-stable composite phase change materials based on lauric acid and graphene/graphene oxide complex aerogels for enhancement of thermal energy storage and electrical conduction [Thermochimica Acta]

• Performance analysis of PCM based thermal energy storage system containing nanoparticles [International Research Journal of Engineering and Technology]

• Cold temperature performance of phase change material based battery thermal management systems [Energy Reports]

• Design and functionality of a segmented heat-storage prototype utilizing stable supercooling of sodium acetate trihydrate in a solar heating system [Applied Energy]

• Macro-encapsulation and characterization of chloride based inorganic phase change materials for high temperature thermal energy storage systems [Applied Energy]

• Parametric analysis of a residential building with phase change material (PCM)-enhanced drywall, precooling, and variable electric rates in a hot and dry climate [Applied Energy]

• Fabrication of high thermal conductive shape-stabilized polyethylene glycol/silica phase change composite by two-step sol gel method [Composites Part A: Applied Science and Manufacturing]

• Performance enhancement of cold thermal energy storage system using nanofluid phase change materials: A review [International Communications in Heat and Mass Transfer]

• Development of form stable Poly(methyl methacrylate) (PMMA) coated thermal phase change material for solar water heater applications [IOP Conference Series: Earth and Environmental Science]

• Design and Analysis of PCM Based Radiant Heat Exchanger for Thermal Management of Buildings [Energy and Buildings]

• A new ventilated window with PCM heat exchanger – performance analysis and design optimization [Energy and Buildings]

• Thermal enhancement of paraffin/hydrophobic expanded perlite granular phase change composite using graphene nanoplatelets [Energy and Buildings]

• Thermal Performance of Microencapsulated Phase Change Material (mPCM) in Roof Modules during Daily Operation [Energies]

• Synthesis and Characterization of Thermochemical Storage Material Combining Porous Zeolite and Inorganic Salts [Heat Transfer Engineering]

• Effect of percussion vibration on solidification of supercooled salt hydrate PCM in thermal storage unit [Renewable Energy]

• A review of the applications of phase change materials in cooling, heating and power generation in different temperature ranges [Applied Energy]

• Experimental and numerical study on the performance of a new high-temperature packed-bed thermal energy storage system with macroencapsulation of molten salt phase change material [Applied Energy]

• Energy and exergy efficiencies assessment for a stratified cold thermal energy storage [Applied Energy]

• Eccentricity optimization of a horizontal shell-and-tube latent-heat thermal energy storage unit based on melting and melting-solidifying performance [Applied Energy]

• Numerical study on the thermal performance of lightweight temporary building integrated with phase change materials [Applied Thermal Engineering]

• Thiol-yne photo-clickable electrospun phase change materials for thermal energy storage [Reactive and Functional Polymers]

• Highly Graphitized 3D Network Carbon for Shape-stabilized Composite PCMs with Superior Thermal Energy Harvesting [Nano Energy]

• Evolution of global heat transfer coefficient on PCM energy storage cycles [Energy Procedia]

• Thermal performance analysis of a cascaded cold storage unit using multiple PCMs [Energy]

• An experimental investigation of discharge/solidification cycle of paraffin in novel shell and tube with longitudinal fins based latent heat storage system [Energy Conversion and Management]

• An alternative approach for assessing the benefit of phase change materials in solar domestic hot water systems [Solar Energy]

• Organic-inorganic hybrid shell microencapsulated phase change materials prepared from SiO2/TiC-stabilized pickering emulsion polymerization [Solar Energy Materials and Solar Cells]

• Preparation of phase change material emulsions with good stability and little supercooling by using a mixed polymeric emulsifier for thermal energy storage [Solar Energy Materials and Solar Cells]

• Optimal design of PCM thermal storage tank and its application for winter available open-air swimming pool [Applied Energy]

• Reduction of supercooling in paraffin phase change slurry by polyvinyl alcohol [International Journal of Refrigeration]

• Preparation, characterization, and thermal stability of double-composition shell microencapsulated phase change material by interfacial polymerization [Colloid and Polymer Science]

• Heat transfer characteristics of a hybrid thermal energy storage tank with Phase Change Materials (PCMs) during indirect charging using isothermal coil heat exchanger [Solar Energy]

• Hybrid network structure of boron nitride and graphene oxide in shape-stabilized composite phase change materials with enhanced thermal conductivity and light-to-electric energy conversion capability [Solar Energy Materials and Solar Cells]

• Encapsulated Nitrates Phase Change Material Selection for Use as Thermal Storage and Heat Transfer Materials at High Temperature in Concentrated Solar Power Plants [Energies 2017]

• Novel shape stabilized phase change material based on epoxy matrix with ultrahigh cycle life for thermal energy storage [Applied Thermal Engineering]

• Thermal and electrical performance of a PV module integrated with double layers of water-saturated MEPCM [Applied Thermal Engineering]

• Investigation on thermal and mechanical characteristics of concrete mixed with shape stabilized phase change material for mix design [Construction and Building Materials]

• Thermal properties and thermal conductivity enhancement of composite phase change materials using myristyl alcohol/metal foam for solar thermal storage [Solar Energy Materials and Solar Cells]

• Experimental and Numerical Study on Energy Performance of Buildings Integrated with Phase Change Materials [Energy Procedia]

• Evaluation on Performance of a Phase Change Material Based Cold Storage House [Energy Procedia]

• Using Phase Change Materials to Reduce Overheating Issues in UK Residential Buildings [Energy Procedia]

• Effect of Supercooling on the Solidification Process of the Phase Change Material [Energy Procedia]

• Experimental Investigation of a Spiral Tube Embedded Latent Thermal Energy Storage Tank Using Paraffin as PCM [Energy Procedia]

• Investigation of specific heat and latent heat enhancement in hydrate salt based TiO2 nanofluid phase change material [Applied Thermal Engineering]

• Modeling and investigation of high temperature phase change materials (PCM) in different storage tank configurations [Journal of Cleaner Production]

• Lauric acid/modified sepiolite composite as a form-stable phase change material for thermal energy storage [Applied Clay Science]

• A review on supercooling of phase change materials in thermal energy storage systems [Renewable and Sustainable Energy Reviews]

• Numerical calibration and experimental validation of a PCM-air heat exchanger model [Applied Thermal Engineering]

• Cold Storage for a Single-Family House in Italy [Energies]

• Thermal energy storage characteristics of poly(styrene-co-maleic anhydride)-graft-PEG as polymeric solid–solid phase change materials [Solar Energy Materials and Solar Cells]

• Sepiolite supported stearic acid composites for thermal energy storage [RSC Advances]

• Thermal stability of renewable diesters as phase change materials [Thermochimica Acta]

• Synthesis and properties of microencapsulated octadecane with silica shell as shape–stabilized thermal energy storage materials [Solar Energy Materials and Solar Cells]

• Synthesis and characterization of novel solid-solid phase change materials with polyurethaneurea copolymer structure for thermal energy storage [RSC Advances]

• A novel multi-dimensional model for solidification process with supercooling [International Journal of Heat and Mass Transfer]

• Assessment of a mattress with phase change materials using a thermal and perception test [Experimental Thermal and Fluid Science]

• Energy Accumulation Using Encapsulated Phase Change Materials with Recycled Material Components [Energy Procedia]