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The award-winning Phase Change Matters blog tracks the latest news and research on phase change materials and thermal energy storage. E-mail tips and comments to Ben Welter, communications director at Entropy Solutions. Follow the blog on Twitter at @PureTemp. Subscribe to the weekly PCM newsletter. Or join the discussion on LinkedIn.

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Paraffin-enhanced concrete shows promise in melting ice, snow

Ben Welter - Monday, September 25, 2017

PCM LWA video

Dr. Yaghoob Farnam has spent four years combining concrete and phase change material in various ways in a quest to develop a durable paving material that can melt ice and snow. 

Farnam, an assistant professor in Drexel University’s College of Engineering, has previously measured the effectiveness of paraffin oil and methyl laurate, materials that have relatively high heat storage capacity (about 130 to 170 joules per gram) and a suitable phase transformation temperature (about 2 to 3 degrees Celsius). Both showed promise when contained in plastic tubes embedded in concrete. But the paraffin oil proved to be far more effective than methyl laurate in concrete made of lightweight aggregate infused with the PCMs. Chemical reactions between the methyl laurate and materials in the cement rendered that PCM ineffective and also appeared to cause cracks in the concrete.

In his latest paper, published in Cement and Concrete Composites, Farnam's research team focused on paraffin oil. The team used concrete slabs to compare two methods of deploying the PCM. Steel pipes filled with paraffin and sealed with PVC caps were embedded in one slab. A second slab was made of porous lightweight aggregate infused with paraffin. A third slab, containing no paraffin, served as a reference point. Each slab was sealed in an insulated container and then covered with about 5 inches of shaved ice.

DrexelNow describes what happened in two tests:

"With temperatures inside the boxes held between 35-44 degrees Fahrenheit, both of the paraffin-treated slabs were able to completely melt the snow within the first 25 hours of testing, while the snow on the reference sample remained frozen. The slab with the paraffin-filled tubes melted the snow slightly faster than the one composed of paraffin-treated aggregate. Farnam suggests that this is because the paraffin inside the tubes is able to solidify more quickly — thus releasing its energy — because of the regular diameter of the pipes. While the diameter of the pores of the aggregate vary in size.

"But in the group’s second experiment, in which the ambient air temperature in the box was lowered to freezing before the snow was added, the paraffin-treated aggregate was more effective than the embedded pipes. This is because the capillary pore pressure delayed the freezing of the paraffin, thus allowing it to release its heat energy over a longer period of time." 

The research is of particular importance to the airline industry, which has a keen interest in finding cost-effective and environmentally friendly ways to clear runways of ice and snow. The Federal Aviation Administration has supported Farnam's work with nearly $500,000 in grants through its PEGASAS program.

Farnam says additional research is needed to better understand how the addition of PCM affects pavement durability, skid resistance and long-term stability.  

http://drexel.edu/now/archive/2017/September/self-melting-concrete-roads/

German researchers roll out PCM warming mats for greenhouse plants

Ben Welter - Tuesday, September 19, 2017

Researchers at the University of Zwickau's Institute for Textile and Leather Technologies are developing a latent heat storage mat that uses phase change material to increase plant root temperatures in cold seasons. 

Dr. Silke HessburgThe passive system, designed for use in greenhouses, requires no additional energy supply. Dr. Silke Hessberg, who is directing the research, says root climate control promotes plant growth efficiently.

"There are already various heating systems on the market, such as underfloor heating systems, hot water systems or electric and gas heaters," she says. "These are always cost-intensive heating systems, since energy must be actively supplied."

The Thuringian Institute of Textile and Plastics Research (TITK) is supporting the two-year project. TITK's Martin Geissenhöner identifies the PCM as paraffin. 

"We have different melting points. For the root project we use melting points between 5 and 42° C, specially 17° C," he says. "The PCM is encapsulated in a network polymer. It's like a sponge structure."

Research associate Nancy Schrader says the mats are placed on the soil surface. Work on the project began in May 2015 and is expected to conclude in December. 

Research roundup: Flexible PCMs with high thermal conductivity; treatment for exercise-induced muscle damage; more

Ben Welter - Thursday, August 31, 2017

Thermal sensitive flexible phase change materials with high thermal conductivity for thermal energy storage [Energy Conversion and Management]

The efficacy of cooling with phase change material for the treatment of exercise-induced muscle damage: pilot study [Journal of Sports Sciences]

Form-stable phase change material based on Na2CO3·10H2O-Na2HPO4·12H2O eutectic hydrated salt/expanded graphite oxide composite: The influence of chemical structures of expanded graphite oxide [Renewable Energy]

Structure and Thermal Performances of Paraffin/Diatomite Form-stable Phase Change Materials [Chinese Journal of Materials Research]

Research roundup: Carbonized rice; erythritol-xylitol; integrated double skin façade; paraffin-based TES system; more

Ben Welter - Wednesday, August 30, 2017

Form stable composite phase change materials from palmitic-lauric acid eutectic mixture and carbonized abandoned rice: preparation, characterization, and thermal conductivity enhancement [Energy and Buildings]

Mitigation against Crude Oil Wax Solidification using TES Fin [Chemical Engineering Research and Design]

Heat transfer analysis of an integrated double skin façade and phase change material blind system [Building and Environment]

Experimental Phase Diagram Study of the Binary Polyols System Erythritol-Xylitol [Solar Energy Materials and Solar Cells]

Study of Various Aspects of Phase Change Material During Solidification and Melting: A Review [pdf] [International Journal of Scientific Research in Science and Technology]

Development in Paraffin Based Thermal Storage System Through Shell and Tubes Heat Exchanger With Vertical Fins [ASME 2017 11th International Conference on Energy Sustainability]

Europe holds PCM market lead, but North America is gaining

Ben Welter - Monday, August 28, 2017

In terms of value, Europe held the largest share of the global PCM market last year, according to the research firm MarketsandMarkets. An executive summary of the research firm's June report, "Advanced PCM Market: Global Forecast to 2022," estimates Europe's share at 49.7 percent.

"The trend towards energy efficiency in the region, accompanied by the growing demand for green buildings, fuels the growth of the advanced PCM market in the region," the summary says. "In addition, the presence of mandatory building energy codes and the increasing demand for housing in Germany and the U.K. drive the demand for advanced PCM in the region."

But MarketsandMarkets projects that North America will be the fastest-growing market for advanced PCMs between 2017 and 2022, with a compound annual growth rate of nearly 21 percent. Analyst Sushmita Singh cites "stringent building energy codes," growth in the housing sector and rising demand for green buildings as key factors.

This MarketsandMarkets graphic shows 2016 market shares in terms of value and compound annual growth rates (CAGR) between 2017 and 2022:

Research roundup: HDPE spheres; erythritol-based composites; shape-stabilized PCM sheets; graphite foam; more

Ben Welter - Wednesday, August 23, 2017

High density polyethylene spheres with PCM for domestic hot water applications: Water tank and laboratory scale study [Journal of Energy Storage]

Numerical Simulation and Optimization of the Melting Process of Phase Change Material inside Horizontal Annulus [Energies]

Evaluation and comparison of erythritol-based composites with addition of expanded graphite and carbon nanotubes [Applied Energy]

Investigation of thermo-fluidic performance of phase change material slurry and energy transport characteristics [Applied Energy]

Numerical investigation of heat transfer performance of a rotating latent heat thermal energy storage [Applied Energy]

Application of shape-stabilized phase-change material sheets as thermal energy storage to reduce heating load in Japanese climate [Building and Environment]

Graphite foam as interpenetrating matrices for phase change paraffin wax: A candidate composite for low temperature thermal energy storage [Solar Energy Materials and Solar Cells]

Alkali polyphosphates as new potential materials for thermal energy storage [Solar Energy]

Magnesium phosphate cements formulated with low grade magnesium oxide incorporating phase change materials for thermal energy storage [Construction and Building Materials]

Numerical and experimental investigation of an insulation layer with phase change materials (PCMs) [Energy and Buildings]

Research roundup: Geopolymer concrete; octyl, decyl, dodecyl and tetradecyl stearates; supercooling suppression of erythritol; more

Ben Welter - Thursday, August 03, 2017

From Cement and Concrete Research:

Mechanical properties and microscale changes of geopolymer concrete and Portland cement concrete containing micro-encapsulated phase change materials

From Applied Energy:

Impact of pressure on the dynamic behavior of CO2 hydrate slurry in a stirred tank reactor applied to cold thermal energy storage

From International Journal of Refrigeration:

Parametric analysis of domestic refrigerators using PCM heat exchanger

From American Institute of Physics:

Utilization of the PCM Latent Heat for Energy Savings in Buildings [pdf]

From Journal of Cleaner Production:

LCA perspective to assess the environmental impact of a novel PCM-based cold storage unit for the civil air conditioning

From Renewable Energy:

A calcium chloride hexahydrate/expanded perlite composite with good heat storage and insulation properties for building energy conservation
Ionic compounds derived from crude glycerol: Thermal energy storage capability evaluation
Comparative study of the thermal performance of four different shell-and-tube heat exchangers used as latent heat thermal energy storage systems

From Materials Today: Proceedings:

Viscoelastic characterization of multifunctional composites incorporated with microencapsulated phase change materials

From Applied Thermal Engineering:

Effect of phase change material wall on natural convection heat transfer inside an air filled enclosure
A numerical study of building integrated with CaCl2·6H2O/expanded graphite composite phase change material
Study of the thermal behavior of the composite phase change material (PCM) room in summer and winter

From Applied Polymer Science:

Emulsion-electrospinning n-octadecane/silk composite fiber as environmental-friendly form-stable phase change materials

From Journal of Materials Chemistry A:

Versatility of polyethylene glycol (PEG) in designing solid-solid phase change materials (PCMs) for thermal management and their application to innovative technologies

From Materials:

Influence of Microencapsulated Phase Change Material (PCM) Addition on (Micro) Mechanical Properties of Cement Paste
Investigation of the Dynamic Melting Process in a Thermal Energy Storage Unit Using a Helical Coil Heat Exchanger

From Energy and Buildings:

Experimental analysis of thermal performance in buildings with shape-stabilized phase change materials
Preparation and thermal properties of octyl, decyl, dodecyl and tetradecyl stearates as phase change materials for thermal energy storage
Effect of PCM application inside an evacuated tube collector on the thermal performance of a domestic hot water system

From Solar Energy:

Experimental investigation of water based photovoltaic/thermal (PV/T) system with and without phase change material (PCM)
Heat transfer studies of building brick containing phase change materials
Experimental investigations on stable supercooling performance of sodium acetate trihydrate PCM for thermal storage

From Solar Energy Materials and Solar Cells:

Supercooling suppression and thermal behavior improvement of erythritol as phase change material for thermal energy storage
MgCl2·6H2O-Mg(NO3)2·6H2O eutectic/SiO2 composite phase change material with improved thermal reliability and enhanced thermal conductivity

Research roundup: Macro-packed fatty acid ester composites; selective laser sintering; more

Ben Welter - Tuesday, July 11, 2017

From Journal of Industrial and Engineering Chemistry:

Performance evaluation of macro-packed fatty acid ester composites using energy-efficient thermal storage systems

From Procedia Manufacturing:

Selective Laser Sintering of Phase Change Materials for Thermal Energy Storage Applications

From Applied Energy:

Synthesis and characterization of microencapsulated myristic acid–palmitic acid eutectic mixture as phase change material for thermal energy storage
Advances in thermal energy storage materials and their applications towards zero energy buildings: A critical review

From Solar Energy Materials and Solar Cells:

A new strategy for enhanced latent heat energy storage with microencapsulated phase change material saturated in metal foam
Preparation and characterization of hybrid nanocomposite embedded organic methyl ester as phase change material

From Renewable Energy:

Cutting copper fiber/paraffin composite phase change material discharging experimental study based on heat dissipation capability of Li-ion battery

From Lehigh University:

Numerical and Experimental Study of the Melting Process of a Phase Change Material in a Partically Filled Spherical Shell [thesis]

From IEEE Internet Computing:

Thermal Time Shifting: Decreasing Datacenter Cooling Costs with Phase Change Materials

From International Journal of Heat and Mass Transfer:

Numerical modeling of solid-liquid phase change in a closed 2D cavity with density change, elastic wall and natural convection

From Applied Thermal Engineering:

Evaluation of the suitability of different calorimetric methods to determine the enthalpy-temperature curve of granular PCM composites
Heat Transfer Enhancement during Freezing Process of Nano Phase Change Material (NPCM) In a Spherical Capsule
Numerical simulation on thermal characteristics of supercooled salt hydrate PCM for energy storage: Multiphase model

Research roundup: INPATH-TES Ph.D. program; waste-to-energy plants; EnergyPlus-based building model; more

Ben Welter - Thursday, June 29, 2017

INPATH-TES: Innovative pathways to PhD research in thermal energy storage [Sustainable and Renewable Energy Engineering]

Application of high temperature phase change materials for improved efficiency in waste-to-energy plants [Waste Management]

Experimental investigation and EnergyPlus-based model prediction of thermal behavior of building containing phase change material [Journal of Building Engineering]

Experimental Analysis of Graphite Dispersed Salt Hydrates based Phase Change Materials to Determine Enhancement in their Thermophysical Properties [pdf] [Journal of Chemical and Pharmaceutical Sciences]

Use of phase change materials during compressed air expansion for isothermal CAES plants [35th UIT Heat Transfer Conference]

Simulation of Melting Process of a Phase Change Material (PCM) using ANSYS (Fluent) [pdf] [International Research Journal of Engineering and Technology]

Cellulose/Paraffin Composite Fibers for Thermal Energy Storage and Temperature Regulation [IUMRS International Conference in Asia]

Enhanced Specific Heat Capacity of Binary Chloride Salt by Dissolving Magnesium for High-temperature Thermal Energy Storage and Transfer [Journal of Materials Chemistry A]

Research roundup: Graphite particle fillers; sodium nitrate microcapsules; domestic space heating in UK; more

Ben Welter - Tuesday, June 27, 2017

Effect of temperature and graphite particle fillers on thermal conductivity and viscosity of phase change material n-eicosane [International Journal of Heat and Mass Transfer]

Thermal stability of sodium nitrate microcapsules for high-temperature thermal energy storage [Solar Energy Materials and Solar Cells]

Phase change materials to meet domestic space heating demand in the UK - A numerical study [Journal of Fluid Flow, Heat and Mass Transfer]

Synthesis of three-dimensional graphene aerogel encapsulating n-octadecane for enhancing phase-change behavior and thermal conductivity [Journal of Materials Chemistry A]

A recyclable thermochromic elastic phase change oleogel for cold compress therapy [Applied Thermal Engineering]