Heating, ventilation and air conditioning (HVAC) systems keep us warm, cool and comfortable as weather conditions impact the temperatures inside homes, spaces and other indoor environments. However, HVAC systems tend to use up a lot of energy, and alternative technologies have been explored to develop more energy-efficient temperature regulation systems. Researchers at Texas A&M University recently developed a novel composite phase-change material (PCM) that can regulate ambient temperatures inside buildings and be 3D-printed for cost-effective manufacturing.
Phase-change materials can regulate temperature without an external energy source by converting to a liquid phase while absorbing heat and to a solid phase when releasing heat. PCMs have been explored as an HVAC alternative and incorporated into building materials, which requires each PCM particle to be encapsulated within another material shell to prevent leakage of the liquid phase. This limits the number of PMC particles that can be incorporated within a certain volume of building material. The Texas A&M team sought to remove the need for encapsulation in order to allow more PCM particles to be packed closely together.
The researchers created a composite material consisting of phase-changing paraffin wax powder and liquid resin, the latter of which would act as both a shell for the paraffin wax particles and as a building material. The malleable composite material was found to be a suitable ink for 3D printing, and the light-sensitive resin the researchers used could be cured with UV light after printing to create a solid 3D structure suitable for real-world applications.
The composite ink was used to print a small hollow house-shaped model in order to test the thermoregulation abilities of the material. Measuring the temperature inside the miniature house when it was placed in an oven showed that its temperature differed by 40% compared to the outside environment for both heating and cooling thermal cycles. The PCM/resin model also showed better thermoregulation compared to models made from traditional materials. The research was published in the journal Matter.
“We’re excited about the potential of our material to keep buildings comfortable while reducing energy consumption,” said first author Peiran Wei. “We can combine multiple PCMs with different melting temperatures and precisely distribute them into various areas of a single printed object to function throughout all four seasons and across the globe.”
The PCM/resin mixture could potentially be added to other building materials, such as paint, or 3D printed as decorative home accents to integrate into different indoor environments. In the future, the researchers plan to experiment with different phase-change materials to produce composites that can operate at broader temperature ranges and manage more thermal energy during a given cycle.
Photo: Researchers developed a new 3D-printable phase-change material composite that can regulate ambient temperatures inside buildings. Credit: Texas A&M University College of Engineering