International News
NEW PHASE-CHANGING COMPOSITE REGULATES INDOOR TEMPERATURES
By Dharmesh Patel
As temperature fluctuations become more commonplace around the world , conventional power-guzzling cooling and heating systems need a more innovative , energyefficient alternative , and in turn , lessen the burden on already struggling power grids .
Changing climate patterns have left millions of people vulnerable to weather extremes . In a new study , researchers at Texas A & M University have created novel 3D printable phase-change material ( PCM ) composites that can regulate ambient temperatures inside buildings using a simpler and cost-effective manufacturing process .
Furthermore , these composites can be added to building materials , like paint , or 3D printed as decorative home accents to seamlessly integrate into different indoor environments .
“ The ability to integrate phase-change materials into building materials using a scalable method opens opportunities to produce more passive temperature regulation in both new builds and already existing structures ,” said Dr Emily Pentzer , associate professor in the Department of Materials Science and Engineering and the Department of Chemistry .
Heating , ventilation , and air conditioning ( HVAC ) systems are the most commonly used methods to regulate temperatures in residential and commercial establishments . However , these systems guzzle a lot of energy . Furthermore , they use greenhouse materials ( refrigerants ), for generating cool , dry air . These ongoing issues with HVAC systems have triggered research into alternative materials and technologies that require less energy to function and can regulate temperature commensurate to HVAC systems .
One of the materials that has gained a lot of interest for temperature regulation is phase-change materials . As the name suggests , these compounds change their physical state depending on the temperature in the environment . So , when phase-change materials store heat , they convert from solid to liquid upon absorbing heat and vice versa when they release heat . Thus , unlike HVAC systems that rely solely on external power to heat and cool , these materials are passive components , requiring no external electricity to regulate temperature .
The traditional approach to manufacturing PCM building materials requires forming a separate shell around each PCM particle , like a cup to hold water , then adding these
Dharmesh Patel
The new phase-change material composites can regulate ambient temperatures inside buildings .
newly encased PCMs to building materials . However , finding building materials compatible with both the PCM and its shell has been a challenge . In addition , this conventional method also decreases the number of PCM particles that can be incorporated into building materials .
“ One of the materials that has gained a lot of interest for temperature regulation is phasechange materials . ”
“ Imagine filling a pot with eggs and water ,” said Ciera Cipriani , NASA Space Technology Graduate Research Fellow in the Department of Materials Science and Engineering . “ If each egg has to be placed in an individual container to be hardboiled , fewer eggs will fit in the pot . By removing the plastic containers , the veritable shell in our research , more eggs , or PCMs , can occupy a greater volume by packing closer together within the water / resin .”
To overcome these challenges , past studies have shown that when using phase-changing paraffin wax mixed with liquid resin , the resin acts as both the shell and building material . This method locks the PCM particles inside their individual pockets , allowing them to safely undergo a phase change and manage thermal energy without leakage .
www . hvacronline . co . za RACA Journal I September 2021 15