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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.




Prefab Carbon Positive House can be assembled in less than a day

Ben Welter - Thursday, November 12, 2015

ArchiBlox Carbon Positive House

ArchiBlox, an Australian design-build firm that specializes in prefab buildings, has designed a sustainable house that can be assembled in just six hours. 

"We call the house Carbon Positive, because we’re positively putting energy back into the grid," Bill McCorkell, owner and director of the Victoria-based company, said in an interview with The Fifth Estate. "This is due to the five solar panels mounted on the roof that produce electricity, and the fact that the house requires no mechanical cooling or heating.”

The 5-kilowatt-hour solar panels produce more than enough electricity to power the hot water system, LED lights and appliances. Excess electricity can be exported to the grid. 

The home features double-glazed windows and slideable living walls and roof to reduce sun penetration as needed. Phase change material in the ceiling absorbs daytime heat and releases it when the temperature falls below 18° Celsius. The price for the one-bedroom, one-bathroom standard model: $286,000 AUD.

Research roundup: Thermal characteristics of microencapsulated PCM; expanded graphite and paraffin; problems associated with PCMs; more

Ben Welter - Thursday, November 05, 2015

Micro-Encapsulated Phase-Change Materials for Latent-Heat Storage: Thermal Characteristics [pdf] [Materials and Technology]

Improvement of thermal conductivity of paraffin by adding expanded graphite [Journal of Composite Materials]

Figure of Merit for the Thermal Performance of Cementitious Composites Containing Phase Change Materials [Cement and Concrete Composites]

SigmaPipe as an Education Tool for Engineers [Education for Chemical Engineers]

Experimental study on crystallization process and prediction for the latent heat of ice slurry generation based sodium chloride solution [Applied Energy]

Review on Latent Heat Storage and Problems Associated With Phase Change Materials [pdf] [International Journal of Research in Engineering and Technology]

Smart Building: Decision Making Architecture for Thermal Energy Management [Sensors]

Viessmann ice store system featured in UK show house

Ben Welter - Thursday, October 29, 2015

Huf Haus show house in Surrey, England

A heat pump system that uses an ice store to both heat and cool buildings has been installed at a show house in England.

Huf Haus' post-and-beam show home in Surrey is equipped with the ice store system, developed by Viessmann, a German company that manufactures heating systems. The system is one of the sustainable elements showcased in Huf Haus’ first UK show home.

The heat pump extracts energy from stored water. As this energy is used, especially during the heating season, the temperature of the water in the ice store falls. If the temperature in the store falls to the freezing point, additional energy is obtained from the freezing of the water. The system is also used to heat water for domestic use.

Voting is open for Solar Decathlon 'fan favorite'

Ben Welter - Friday, October 16, 2015

Fourteen houses entered in the U.S. Energy Department's 2015 Solar Decathlon have been assembled in Irvine, Calif., and are on public display through Sunday. It's a diverse collection of energy-efficient dwellings designed by collegiate teams from the United States, Germany, Honduras and Panama. The teams and their solar-powered houses are competing in 10 contests to determine an overall winner. Judges award points based on a home's affordability, attractiveness, comfort and net energy consumption. The winner will be announced Saturday.

Can't make it to Irvine this weekend? You can tour the houses online and vote for your favorite. Voting ends Sunday; the "fan favorite" will be announced on Monday.

PCM-based free cooling in buildings: A way forward

Ben Welter - Wednesday, October 07, 2015

A review of research on PCM-based free cooling in buildings suggests that increased thermal conductivity, wider governmental support and heightened public awareness are essential to wider adoption of the technology. Among the other conclusions by a team of researchers at two universities in India:

• The free-cooling concept is best suited for less humid and maximum diurnal temperature range regions. However, with careful design of heat exchangers along with dehumidification of air, free cooling can be effectively implemented even in warm and humid areas.

• By decreasing the inlet air temperature with optimal inlet air velocity, solidification time can be reduced and thus the PCM can be charged in less time.

• Supercooling can be reduced by adding nucleating agents but cannot be mitigated completely.

• Mapping of free-cooling potential zones and construction of large-scale demonstration projects are essential to making the technology commercially viable.

• Commercializing and mass implementation of free-cooling technology in residential sectors will curtail air conditioner use and reduce greenhouse gas emissions.

Off-grid passive house packed with high-performance material from around the world

Ben Welter - Friday, September 25, 2015

Building a passive house off-grid without the use of foam insulation or other potentially harmful materials can be a challenge. Architect Andrew Michler scoured the world for the high-performance material used in MARTaK, Colorado's first certified International Passive House. Among the components used in Michler's 1,200-square-foot guest house in the foothills of the Rocky Mountains near Fort Collins: 

Applegate loose-fill cellulose insulation
Roxul mineral wool batt
Air Pohoda heat-recovery ventilator
Eco-Bond nontoxic caulk
Tescon Vana air sealing tape
• ABS pipe to replace PVC

BioPCmat 51

Above: BioPCmat 51, a phase change material designed to absorb and release heat, is installed on two interior walls to even out temperature spikes.

Research roundup: NZEB analysis tool; multistage heat engine model; solar water heater with PCM; more

Ben Welter - Tuesday, August 25, 2015

Innovative technologies for NZEBs: an energy and economic analysis tool and a case study of a non-residential building in Mediterranean climate [Energy and Buildings]

Thermal efficiency analysis of the cascaded latent heat/cold storage with multi-stage heat engine model [Renewable Energy]

Experimental investigation of a domestic solar water heater with solar collector coupled phase-change energy storage [Renewable Energy]

Experimental testing and analysis of R134a clathrates based PCMs for cooling applications [International Journal of Heat and Mass Transfer]

Applications of solar water heating system with phase change material [Renewable and Sustainable Energy Reviews]

Effect of temperature on mortars with incorporation of phase change materials [Construction and Building Materials]

Microencapsulation and characterization of polyamic acid microcapsules containing n-octadecane via electrospraying method [Materials Express] [pdf]

'Post-occupancy evaluation' gains traction among sustainability architects

Ben Welter - Friday, August 07, 2015

Dr. Nancy Foster Florida Keys Environmental Center

"Post-occupancy evaluation," the process of measuring a new building's actual performance, is an essential part of the design feedback loop. Is that impressive-looking thermal energy storage system delivering the projected energy savings? POE is gaining momentum among sustainability architects to address the frequent gap between promises and reality, Peter Fairley writes in this month's issue of Architectural Record. 

Does this scenario sound familiar?

"The value of getting feedback on projects hit home for [New Orleans–based Eskew+Dumez+Ripple] after the opening of its first LEED-certified building: the Dr. Nancy Foster Florida Keys Environmental Center [show above] in Key West. The 30,000-square-foot multipurpose facility, occupied by the U.S. National Oceanic and Atmospheric Administration in 2006, was predicted to consume 735,000 kilowatt-hours per year—28 percent fewer than the ASHRAE baseline. In its first two years of operation, however, the LEED Silver building was consuming almost twice that amount.

"Faulty settings in the building-management system were the culprit: two months after commissioning, a software upgrade wiped out the settings tuned by the commissioning agent. A local consultant's efforts to fix the problem fell short. Ultimately, humidity and mold issues convinced the owner to bring Eskew+Dumez+Ripple and the commissioning agent back into the picture nearly two years later. The problems were then quickly resolved. Energy consumption immediately fell below what designers had originally predicted.

"Eskew+Dumez+Ripple determined that from that point forward they would attempt to track energy consumption of all their LEED projects. They wanted to understand the variables affecting performance and get a jump on any issues that arose. "