Phase Change Matters

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• With an eye toward increased profits, CEO Edward Breen says DowDuPont is moving away from large-scale R&D projects in favor of less risky initiatives of $30 million or less.

• Viking Cold Solutions has posted an opening for a business development manager for the Northeastern United States.

• ASHRAE has published a new standard describing a methodology to apply building energy modeling throughout the design process. ASHRAE Standard 209-2018 defines minimum requirements for providing energy design assistance using building energy simulation and analysis.

• Pelican BioThermal is opening its first Canadian drop point for the Credo on Demand rental program. The new drop point, at ATS Healthcare headquarters in Toronto, offers customers an additional location to return temperature-control pallet and bulk shippers. 

Using a phase change composite material, researchers at the University of Illinois at Chicago have developed a novel thermal energy storage system that has the potential to downsize conventional air-conditioner compressors by 50 percent and double compressor efficiency during off- and mid-peak hours.

The research is described in a paper titled “Design and optimization of a hybrid air conditioning system with thermal energy storage using phase change composite,” recently accepted for publication in Energy Conversion and Management. One of the authors, Said Al-Hallaj, a research professor of chemical engineering at UI-Chicago and CEO of AllCell Technologies LLC, answered a few questions by e-mail.

Q: Who led the research team, and how long did the project take?

A: “It is an ongoing project since 2015 at the University of Illinois at Chicago, where I work as a Research Professor of Chemical Engineering, and part of the PhD thesis for my graduate student Ahmed Aljehani.”

Q: Who funded the project? 

A: “Ahmed has a scholarship from his government in Saudi Arabia and we get technical support from our industry partners NETenergy and AllCell Technologies LLC.”

Q: Who supplied the PCM?

A: “I believe it is n-tetradecane (C14H30) PCM that we bought from a distributor and not sure about actual source.”

Q: What is its peak melting point? 

A: “4-6 degrees Celsius.”

Q: What is its thermal storage capacity?

A: “180 kJ/kg (78% PCM, 22% graphite).”

Q: Describe the benchtop PCC/TES system size, components and functionality.

A: “The actual 4 kWh PCC-TES structure is made of 28 slabs of PCC [right]. The whole PCC-TES structure is thermally insulated with building insulation materials. Each slab represents a graphite structure that has been soaked into n-tetradecane for at least 24 h until impregnated with n-tetradecane. The slabs are numbered from top to bottom; top being number 1. The second component is the copper tubes or the copper coils, which pass back and forth in between the 28 slabs. The copper tubes enter the PCC-TES structure from the top and exits from the bottom of the structure.”

Q: Is the concept intended mainly for commercial AC systems, or could it be adapted for residential use?

A: “It should work for both, but commercial AC applications are more economically beneficial due to rate structure and peak demand requirements.”

Q: What are the next steps in developing this concept?

A: “NETenergy, our technology commercialization partner, is partnering with National Renewable Energy Laboratory and a major OEM to build and test a full-scale prototype at NREL facilities in the next year or so.”

https://www.sciencedirect.com/science/article/pii/S019689041830517X

• Performance enhancement of solar absorption cooling systems using thermal energy storage with phase change materials [Applied Energy]

• Experimental validation of an air-PCM storage unit comparing the Effective Heat Capacity and Enthalpy methods through CFD simulations [Energy]

• Controlling the heat evaluation of cement slurry system used in natural gas hydrate layer by micro-encapsulated phase change materials [Solar Energy]

• Thermal properties and thermal conductivity enhancement of composite phase change material using sodium acetate trihydrate–urea/expanded graphite for radiant floor heating system [Applied Thermal Engineering]

• Study on heat-transfer mechanism of wallboards containing active phase change material and parameter optimization with ventilation [Applied Thermal Engineering]

• Life Cycle Assessment of Innovative Materials for Thermal Energy Storage in Buildings [Procedia CIRP]

• Synthesis and properties of phase change microcapsule with SiO2-TiO2 hybrid shell [Solar Energy]

• Experimental investigation of melting behaviour of phase change material in finned rectangular enclosures under different inclination angles [Experimental Thermal and Fluid Science]

• Phase change material based cooling of photovoltaic panel: A simplified numerical model for the optimization of the phase change material layer and general economic evaluation [Journal of Cleaner Production]

• Influence of glazed roof containing phase change material on indoor thermal environment and energy consumption [Applied Energy]

• Thermal field and heat storage in a cyclic phase change process caused by several moving melting and solidification interfaces in the layer [International Journal of Thermal Sciences]

• A phase change microactuator based on paraffin wax/expanded graphite/nickel particle composite with induction heating [Sensors and Actuators A: Physical]

U.S. patent application 20180094180 (applicant Hutchinson SA, Paris, France):

"The invention relates to a material including a support consisting of a porous composite material including at least one polymer phase forming a binder based on at least one polymer selected from thermoplastic polymers, elastomers, and elastomer thermoplastics, and at least one filler selected from thermally conductive fillers, the pores of the support consisting of the porous composite material being partially or entirely filled with at least one phase-change material. The invention also relates to a method for producing said material."

http://www.freepatentsonline.com/20180094180.pdf