Adaptive tiles reduce heating and cooling costs

Wax motor moves slats

January 29, 2024 1:16 p.m. Robert Klatt

An adaptive tile can change surfaces using a built-in wax motor. This significantly reduces the energy requirements of heating and cooling systems.

Santa Barbara (United States). In the United States, heating and cooling account for approximately 50% of the energy consumption of a typical building. According to a study by the University of Venice, energy demand is likely to continue to increase due to climate change. Researchers are therefore always looking for new heating and cooling technologies requiring less energy, including a new cooling system based on the electrocaloric effect that researchers at the Luxembourg Institute of Science and technology (LIST) recently developed .

Scientist of University of California, Santa Barbara (UCSB) led by Charlie Xiao presented an adaptive tile that can significantly reduce summer cooling costs and winter heating costs without the use of electronics.

“It switches between a heating state and a cooling state depending on the temperature of the brick. The target temperature is around 18 degrees Celsius.

According to the publication in the specialist magazine Device The innovative tile is approximately ten centimeters high and has a surface whose thermal properties can change depending on the temperature.

Tiles with wax engine

The adaptive tile is based on a wax motor in which changes in temperature cause changes in the volume of the wax, which in turn generate pressure and thus move the mechanical parts. The wax engine therefore converts thermal energy into mechanical energy.

Depending on the temperature, the wax motor on the tile moves pistons that open and close the slats on the surface. If the temperature is low, the wax solidifies and the slats close. This exposed surface can absorb sunlight well and thus warm the building.

When a temperature of 18 degrees Celsius is reached, the wax melts and expands. This opens the slats and exposes a surface that reflects incoming sunlight, thereby cooling the building. Additionally, the wax releases heat during the melting or freezing process, stabilizing the temperature of the building.

“So we have very predictable switching behavior that operates within a very narrow range.”

Significantly reduced energy requirements

In experiments, the adaptive tile was able to reduce energy requirements for cooling by 3.1 times and heating by 2.6 times. Electronics, batteries or external power sources are not required thanks to the wax motor. Moreover, according to the researchers, thanks to its simple design, it is easy to adapt to different thermal coatings. As Elliot Hawkes explains, industrial mass production is in principle also possible.

“The device is still a proof of concept, but we hope it will lead to new technologies that could one day have a positive impact on the energy consumption of buildings.”

Device, doi: 10.1016/j.device.2023.100186