researchers at empa (the swiss federal laboratories for materials science and technology) in dubendorf, switzerland have developed a paste of highly-porous aerogel particles with high thermal insulation properties to be used as filler material for bricks.

insulates as well as no other brick: the aerogel-filled aerobrick. (empa)

according to a report from empa, this aerogel mixture easily fills the cavities inside bricks and reduces the overall thickness of the brick layer that is needed to meet required thermal insulation levels.

the new bricks, dubbed aerobricks by researchers, can be used like typical bricks because the aerogel stays inside the cavity.

“a comparison in a special measuring device for thermal conductivity at an average temperature of 10°c shows that the perlite-filled bricks with the same structure and thickness insulate by about a third less than the aerobrick, the article explained. “in other words, in order to achieve the required insulation values, a wall of perlite brick must be about 35% thicker than an aerobrick wall.”

ordinary bricks conduct heat eight times better than aerobricks, requiring a conventional wall to be two meters thick to match the insulating capability of an aerobrick wall that is only 20 centimeters deep.

“with a measured thermal conductivity of just 59 milliwatts per square meter,” the article continued, “and kelvin temperature difference, the aerobrick is currently the best insulating brick in the world.”

expense is still a major concern for the new aerobrick, as the filling material costs too much for practical construction projects, but the researchers believe costs will drop for the material and that it is the future.

the work was recently published in energy procedia. the abstract of the report stated:

“insulating bricks constitute an interesting alternative to the common approach of a layered construction as they incorporate both the structural and the thermal functions of the building envelope. different types of insulating bricks are commercially available using air, mineral wool, eps or perlite as a filling material, with thermal conductivities as low as 70-90 mw/(m·k).

“in this study, we substituted the perlite filling of a commercially available insulating brick with a novel, highly insulating aerogel compound in order to further reduce its thermal conductivity. we determined the thermal conductivity of the perlite- and the aerogel-filled insulating bricks using both a guarded hot-plate setup and thermal simulations.

“the results showed a pronounced decrease of the thermal conductivity from 91 down to 59 mw/(m·k), corresponding to a u-value of these ‘aerobricks’ of only 0.157 w/(m²·k). thus, with an aerogel filling, the thickness of insulating bricks can be reduced. this entails space savings and new architectural possibilities.”