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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.




PCM mats helped lift Virginia Tech to first place in Solar Decathlon

Ben Welter - Monday, February 18, 2019

FutureHAUS, front elevation

The Virginia Tech team that won first place in the 2018 Solar Decathlon Middle East credits a good share of its success to the deft use of phase change material donated by Insolcorp LLC of New London, N.C.

FutureHAUS, the lone U.S. entry, topped 13 other finalists and more than 60 total entrants in the competition organized by the U.S. Department of Energy and the United Arab Emirates’ Dubai Electricity & Water Authority. Australia's University of Wollongong finished second. The finals took place in November in the desert heat of Dubai.

Insolcorp donated 400 square feet of two types of Infinite R PCM mats. Both are salt hydrates, one with a melt point of 21 degrees Celsius, the other a melt point of 22 degrees C. The phase change material acts as a thermal battery, absorbing and releasing thermal energy as it solidifies and melts.

The Virginia Tech team deployed the mats in the plenum of its 900-square-foot solar-powered house. The PCM allowed the team to take advantage of a rule that limited the use of solar energy to 8kw at any one time, with one exception: Unlimited use of solar energy for air conditioning was allowed during daily inspection periods to assure visitor comfort. The PCM mats, solidified during those periods, helped keep the house comfortable at other times. That helped the FutureHAUS achieve the highest score in net energy use, a key metric in the competition.

Joseph Wheeler, AIA"Every team struggled with the 8kw limit," said Joseph Wheeler, right, lead faculty on FutureHAUS and co-director of Virginia Tech's Center for Design Research. "Typically, during peak energy, you would be generating lots and lots of power, which you could easily charge your batteries with, which you could easily run all your tasks, and you could feed the grid, and build up quite a bit of surplus so that you would remain energy positive throughout the two weeks of competition.

"But, since they limited inverter use at any one time to 8kw, it really put a limit to what our energy budget was. We saw phase change as batteries. A massive ton of batteries. ... It's more of a strategy for a competition than it is for a realized situation. But in a realized situation, we know the value of the PCM. Heat energy, cost of power being cheaper at night than during the day where you can charge your systems and load shift. Practically, PCMs make a lot of sense. And we wanted to have the PCMs in this house for practical reasons, not just for competition reasons. ...

"In simple terms, we eased the demand for the HVAC every afternoon. It was the hottest time of the day and it was also the time when we were getting less power from the solar panels because the sun was moving down. It was a critical time because we knew that once the sun went down, we had to survive on battery. And we had a limit. They limited every house to 15kw of battery."

FutureHAUS, kitchenThe FutureHAUS team finished in the top three in eight of the competition's 10 categories: first place in Architecture, House Functioning and Sustainable Transportation; second place in Sustainability and Innovation; and third place in Engineering/Construction, Energy Efficiency and Comfort Conditions.

The FutureHAUS entry was a two-year university-wide effort. More than 100 Virginia Tech students helped design and build the structure, with help from faculty members in architecture, urban studies, science, engineering and other departments.

The house consists of 18 modular  "cartridges" built inside a Virginia Tech research facility. It was first assembled on campus in Blacksburg, Va., last summer. After testing, it was disassembled, shipped to Dubai and then reassembled at the competition site in just two days. It has since been shipped back to Blacksburg, where it will undergo testing to measure its various energy-saving components.

"We now have a system in place where we can collect data and can truly test the performance," Wheeler said. "We know the PCM worked for us during the competition because we did have some temperature sensors in the ceiling. And so we were able to prove that we were reaching the pre-state when those PCMs were being charged. But we really want to collect a lot more data and look at it in real-world situations."

Research roundup: Self-luminous wood composite; palmitic acid/mullite composite; corrosion sensitivity of metal alloys; more

Ben Welter - Tuesday, February 12, 2019

From Energy Storage Materials:

Self-luminous wood composite for both thermal and light energy storage

From International Journal of Refrigeration:

The thermal performances of a refrigerator incorporating a Phase Change Material

From Renewable Energy:

Enhanced thermal conductivity of palmitic acid/mullite phase change composite with graphite powder for thermal energy storage
An experimental study on the corrosion sensitivity of metal alloys for usage in PCM thermal energy storages

From Energy Conversion and Management:

Sorption thermal energy storage: Hybrid coating/granules adsorber design and hybrid TCM/PCM operation
Novel hybrid microencapsulated phase change materials incorporated wallboard for year-long year energy storage in buildings

From Thermochimica Acta:

Experimental Investigation on Thermal Properties of Sodium Acetate Trihydrate based Phase Change Materials for Thermal Energy Storage
The preparation of AgI/Au/foam-Cu as a framework of composite for water-based cool storage phase-change material with low supercooling

From Energy and Buildings:

Nano-encapsulation of phase change materials: from design to thermal performance, simulations and toxicological assessment
Investigation of phase change materials integrated with fin-tube baseboard convector for space heating

From Journal of Energy Storage:

Nano-enhancement of phase change material in a shell and multi-PCM-tube heat exchanger

From Applied Energy:

Numerical investigation of phase change material thermal storage for space cooling

From Journal of Materials Chemistry A:

Vertically aligned carbon fibers as supporting scaffolds for phase change composites with anisotropic thermal-conductivity and good shape-stability

Research roundup: Thermal conductivity; decarbonization potential of compact heat storage; liquid desiccant cooling systems; more

Ben Welter - Wednesday, February 06, 2019

From Energy:

Effects of thermal conductivity and density on phase change materials-based thermal energy storage systems

From Renewable Energy:

Melting process investigation of phase change materials in a shell and tube heat exchanger enhanced with heat pipe

From Applied Thermal Engineering:

Compact latent heat storage decarbonisation potential for domestic hot water and space heating applications in the UK
Numerical and experimental study of phase-change temperature controller containing graded cellular material fabricated by additive manufacturing
A novel composite phase change material with paraffin wax in tailings porous ceramics
Characterisation and evaluation of a new phase change enhanced working solution for liquid desiccant cooling systems
Thermal properties enhancement and application of a novel sodium acetate trihydrate-formamide/expanded graphite shape-stabilized composite phase change material for electric radiant floor heating

From Environmental Research:

Latent heat storage biocomposites of phase change material-biochar as feasible eco-friendly building materials

From Colloids and Surfaces A:

A facile microencapsulation of phase change materials within silicone-based shells by using glass capillary devices

From Microporous and Mesoporous Materials:

Phase change in modified metal organic frameworks MIL-101(Cr): Mechanism on highly improved energy storage performance

From Applied Energy:

Role of porous metal foam on the heat transfer enhancement for a thermal energy storage tube
Energy saving performance assessment and lessons learned from the operation of an active phase change materials system in a multi-storey building in Melbourne

From Building and Environment:

Comparative analysis of the PCM application according to the building type as retrofit system

From Construction and Building Materials:

Evaluation of the potential use of form-stable phase change materials to improve the freeze-thaw resistance of concrete

From Results in Physics:

Application Research of Nano-storage Materials in Cold Chain Logistics of E-commerce Fresh Agricultural Products

From Journal of Energy Storage:

Using PCM as energy storage material in water tanks: Theoretical and experimental investigation

PCM briefing: Cash infusion for PCES; call for e-textile conference papers

Ben Welter - Monday, January 28, 2019

Phase Change Energy Solutions Inc. of Asheboro, N.C., last week announced an investment by Pegasus Capital Advisors, Emerald Technology Ventures and Third Prime, an early-stage venture fund and prior investor. Dennis McGill, operations advisor at Pegasus, joined PCES last month as chief executive officer. The company says it will use the proceeds to fund the continued development of its thermal storage products and expand its operations globally. Terms of the investment were not disclosed. 

Mark RichardsMark Richards, right, CEO at Emery Mechanical Engineering in San Diego, is featured in a recent episode of the HVAC 360 podcast. Richards, former applications engineering manager at Phase Change Energy Solutions, talks about "Phase Change Materials in Practice." 

1414 Degrees of Australia reports that the first commercial pilot of its molten silicon energy storage system is one step closer to commissioning. The GAS-TESS will store energy to generate electricity from biogases produced at a wastewater treatment plant. 

• In collaboration with Canada's Université Laval, researchers at the University of the Basque Country in Spain conclude that "fake ISO 9001 quality certificates are very widespread across Chinese companies and that the certification processes of the auditing companies lack credibility." 

• The Association Connecting Electronics Industries has issued a call for technical conference abstracts and educational course proposals for IPC E-TEXTILES 2019 to be held Sept. 11 in Philadelphia, Pa. Topics include reliability, test methods, design, washability and materials innovation. Abstracts and proposals are due by April 10. 

Research roundup: Micro environmental control system; alkali nitrate salts; sodium thiosulfate pentahydrate; more

Ben Welter - Tuesday, January 22, 2019

From Journal of Thermal Science and Engineering :

Phase Change Material Freezing in an Energy Storage Module for a Micro Environmental Control System
Phase Change Material Melting in an Energy Storage Module for a Micro Environmental Control System

From Renewable Energy:

Form-stable oxalic acid dihydrate/glycolic acid-based composite PCMs for thermal energy storage
Molecular simulation of the structure and physical properties of alkali nitrate salts for thermal energy storage

From Applied Energy:

Effect of inclination on the thermal response of composite phase change materials for thermal energy storage

From Solar Energy Materials and Solar Cells:

Characterization and thermal performance of microencapsulated sodium thiosulfate pentahydrate as phase change material for thermal energy storage
Fabrication and applications of dual-responsive microencapsulated phase change material with enhanced solar energy-storage and solar photocatalytic effectiveness

From Energy:

Numerical investigations of optimal phase change material incorporated into ventilated walls

From Polymer Degradation and Stability:

EG-based coatings for flame retardance of shape stabilized phase change materials

From Construction and Building Materials:

Freeze-thaw performance of phase change material (PCM) incorporated pavement subgrade soil


PCM briefing: Sunamp among 'Scottish tech companies to watch' in 2019; C-Therm webinar on new thermal conductivity instrument

Ben Welter - Monday, January 07, 2019

Rail shipping container with PCM

• The University of Birmingham's Center for Energy Storage has teamed up with a Chinese railway equipment manufacturer to develop a shipping container that uses phase change materials to maintain a low temperature over several days without a power supply. "Once ‘charged’, PCM inside the container - which can be transferred from train to truck and vice versa - can keep the inside temperature between 5-12 ˚C for up to 120 hours," the university reports.

CNET's Scott Stein takes a close look at PowerStation, "a battery of sorts that can keep a low-power sensor running off the temperature differences in everyday weather conditions." The device, made by Matrix Industries of Menlo Park, Calif., stores heat in a substance the company calls "Luna Phase Change Material" and later releases the heat in the form of electricity.

Scottish Business Insider has named Sunamp Ltd. one of five Scottish tech companies to watch in 2019. "The £2.2m raised in its latest fundraising sets the company up for a Series A round in 2019 as it looks to expand its international footprint and further scale its operations," Insider writes. "Sunamp heat batteries have so far been installed in over a thousand homes across the UK." 

C-Therm managing director Adam Harris is hosting a webinar this week to introduce the company's new thermal conductivity instrument, the C-Therm Trident. Advance registration is required for the webinar, which will be held at 1 p.m. EST Thursday, Jan. 10.

• At a business summit in Wisconsin last month, Encapsys President Mary Goggans said the Appleton-based company offers internships to students at regional colleges, including the children of employees. “The interns see the jobs and technologies they are interested in right here in the area,” Goggans said. “They realize they don’t need to get a job outside of the region to have the career they are looking for.”

Research roundup: Transparent insulation material wall with PCM; industrial waste heat recovery; cotton-derived carbon sponge; more

Ben Welter - Wednesday, December 26, 2018

From Energy:

Energy performance and economic analysis of a TIM-PCM wall under different climates

From Applied Energy:

A modeling study on the heat storage and release characteristics of a phase change material based double-spiral coiled heat exchanger in an air source heat pump for defrosting
Dynamic thermal management for industrial waste heat recovery based on phase change material thermal storage

From Solar Energy:

Modeling of solidification including supercooling effects in a fin-tube heat exchanger based latent heat storage

From Solar Energy Materials and Solar Cells:

Experimental study on thermal properties and thermal performance of eutectic hydrated salts/expanded perlite form-stable phase change materials for passive solar energy utilization
Cotton-derived carbon sponge as support for form-stabilized composite phase change materials with enhanced thermal conductivity
Enhanced thermal conductivity of microencapsulated phase change materials based on graphene oxide and carbon nanotube hybrid filler
A novel core-shell structural montmorillonite nanosheets/stearic acid composite PCM for great promotion of thermal energy storage properties

From Energy and Buildings:

Numerical analysis for maximizing effective energy storage capacity of thermal energy storage systems by enhancing heat transfer in PCM
Optimization of phase change materials (PCMs) to improve energy performance within thermal comfort range in the South Korean climate

From Journal of King Saud University - Science:

Exact and approximate solutions of a phase change problem with the moving phase change material and variable thermal coefficients

From Journal of Molecular Liquids:

Preparation and thermophysical properties of low temperature composite phase change material octanoic-lauric acid/expanded graphite

From International Journal of Refrigeration:

Supercooling characteristics of phase change material particles within phase change emulsions
Enhancement of ice formation around vertical finned tubes for cold storage applications

PCM briefing: Virginia Tech takes first place in Solar Decathlon; Pluss is expanding R&D team

Ben Welter - Monday, December 10, 2018

Virginia Tech's FutureHAUS team has won first place in the 2018 Solar Decathlon Middle East, a competition organized by the U.S. Department of Energy and the United Arab Emirates’ Dubai Electricity & Water Authority. The lone American team topped 14 other finalists and more than 60 total entrants. The team said its use of phase change material in the solar-powered home set it apart from the competition. Look for an interview with Joseph Wheeler, an architecture professor who directs Virginia Tech's FutureHAUS research program, in the next issue of Phase Change Matters.

• Via LinkedIn: "Pluss Advanced Technologies Pvt. Ltd. is hashtag#Expanding its hashtag#Research team for hashtag#PCM Business. Chemistry Graduates with 0-2 years of experience preferred. However, others will be considered too. Usual job descriptions apply! Want to understand more about the opportunity? Please write to Ruchika Garg at Hurry! The vacancies are limited."

• U.S. and German researchers who have studied a PCM alloy made from germanium, antimony and tellurium say liquid water and liquid PCMs may have the same underlying physics. "The experiments reveal that the so-called Stokes-Einstein relation, which connects the viscosity of a liquid to the diffusion coefficient of its molecules, appears to break down above the melting point of the material and at very low viscosities – just as in water," Physics World reports. "The result will be important when making phase-change memories from GeSbTe alloys and related PCMs in the future."

CleanTechnica's Tina Casey takes a deep dive into the U.S. Department of Energy's efforts to develop next-generation, long-duration energy storage systems. Her conclusion: "The new R&D program practically guarantees that the hurt will continue for coal miners, their families and their communities long after Trump leaves office."  

kW Engineering of Oakland, Calif., offers tips on how to use a famously complex energy modeling program: "Best Practices for Successful Building Energy Modeling with EnergyPlus." 

Agenda set for 6th Swiss symposium on thermal energy storage

Ben Welter - Monday, December 03, 2018

The agenda is confirmed for the 6th Swiss Symposium Thermal Energy Storage, to be held in Lucerne, Switzerland, on Jan. 25, 2019. The symposium will focus on seasonal storage systems and the sector coupling of power and heat. Here are the speakers and topics:

• "Heat Storage in Switzerland": Elimar Frank, Frank Energy GmbH, Switzerland

• "Thermal Energy Storage, one Key Element to link Energy Sectors": Peter Schossig, Fraunhofer Institute for Solar Energy Systems ISE, Germany

• "Enhanced Phase-Change Materials for Heat-Storage applications": Colin Pulham, School of Chemistry, University of Edinburgh, United Kingdom

• "High-Temperature Latent Heat Storage and Applications": Dan Bauer, German Aerospace Center (DLR), Stuttgart, Germany

• "High-Temperature Phase Change Materials": Yulong Ding, University of Birmingham, United Kingdom

• "Network Convergence and Sector Coupling at St. Galler Stadtwerke": Simon Schoch, St. Galler Stadtwerke, Switzerland

• "Heat4Cool – Multienergy Solutions for Heating & Cooling": Marcello Aprile, Politecnico di Milano and Philipp Schütz, Lucerne School of Engineering and Architecture, Switzerland

• "Large-Scale Thermal Energy Storage and Multi-Energy Networks in Vienna": Robert Hammerling, Wien Energie GmbH, Austria

• "Current and Future Use of Seasonal Thermal Storage in Ground Heat Exchangers": A Swedish Perspective: José Acuña, KTH Royal Institute of Technology, Sweden

• "Avoided System Cost for Grid Reinforcement and Peaker Plants by using Ecovat Seasonal Thermal Energy Storage": Aris de Groot, Ecovat Renewable Energy Technologies, Netherlands

• "Optimization of Seasonal Thermal Energy Storage Systems for Buildings": Willy Villasmil, Lucerne School of Engineering and Architecture, Switzerland

• "Seasonal Hot Water Storage with Vacuum Super Insulation": Matthias Demharter, Bayerisches Zentrum für Angewandte Energieforschung ZAE, Germany

The registration fee is 300 Swiss francs. Lunch is included. The 2018 symposium drew more than 100 participants.

Patent application: Solid-liquid phase change driven heat engine

Ben Welter - Thursday, November 29, 2018

U.S. patent application 20180320518 (inventor Yanming Wei, Ontario, Canada):

"A new kind of solid-liquid-solid cyclic phase change heat engine is presented with optional but highly recommended multiple cylinders aka multiple stages cascading powertrain. Unlike the traditional Rankine engine or Stirling engine, hereby the gaseous phase is prohibited, and the conventional turbine is abandoned too. Under the drive of heat flux, low expansion volume of the working Phase Change Material (PCM) replaces the high expansion volume of hot gas, and in compensation, high expansion pressure replaces the low expansion pressure of hot gas. ... Inspired by [Donald] Trump's book “the art of deal,” I audaciously make technical trade-off to combine but isolate standard hydraulic oil and PCM in a hydraulic ensemble, despite minor existence of PCM leakage, corrosion and excessive friction, which are caused by the non-ideal viscosity & fluidity."