Novel heat-absorbing material could reduce reliance on air-conditioning

A team of Griffith University engineers have highlighted a novel material that can absorb heat to cool down buildings, reducing the heavy reliance on air-conditioning.

The team, from Griffith’s School of Engineering and Built Environment, conducted a year-long experiment in which they found Phase Change Materials (PCMs) had the ability to absorb several times more heat than concrete.

The findings have been published in the journal of Building and Environment as ‘A parametric study of phase change materialbehaviourwhen used with night ventilation in different climatic zones.’

Study co-author DrRuwanFernando said one way in reducing the demand placed on air-conditioning systems is to have the building store some of the heat and release it at night once it’s cooler.

“The International Energy Agency estimates that worldwide, about a tenth of our total energy is used for air-conditioning,” Dr Fernando said.

“Of even greater concern is the rising demand for air-conditioning in hot and humid countries throughout the world.”

“While we invest in renewable technologies such as solar and wind power, there is simultaneously a need to increase the efficiency with which we use our current energy.

“PCMs store several times more heat for a given volume than conventional construction materials such as concrete. They also have a verylong lifespan.”

PCMs are more readily associated with cooling gel sheets used for migraines and pillows with cooling materials, but they are steadily being adopted by the building industry in new designs that aim to reduce the use of air-conditioning.

The team tested the thermal performance of a full-scale experimental model that validated computer modelling of PCM types and thicknesses, as well as insulation.

“We also looked atutilisinghigh amounts of ventilation, whenever that was a feasible alternative to air-conditioning,” Dr Fernando said.

“In total, more than 37,000 simulations were run, using custom developed software.

“More than half a terabyte of data was produced from the simulations, detailing the thermal performance of each construction over the course of a year, using real weather data.”

The findings revealed that for some Australian climatic zones, phase-change materials could be highly beneficial and offer a good return on investment if the right material and configuration was chosen.