Scientists find eggshells make clay bricks reduce energy consumption by blocking heat

Scientists have discovered that adding eggshell waste to clay bricks can significantly reduce energy consumption by blocking heat transfer. Researchers in Egypt tested fired clay bricks made with eggshell powder and found that the right amount of eggshell waste can decrease thermal conductivity by up to 50%. The study showed that bricks containing 10% eggshell waste had a 30% reduction in thermal diffusivity and thermal effusivity compared to ordinary clay bricks.

To create the eggshell bricks, researchers collected, cleaned, and dried discarded eggshells. The shells were then ground into powder, which was mixed with local clay from Egypt's Kharga Oasis. The powder was added to the clay at varying proportions, ranging from 1% to 10%. The researchers discovered that the eggshell powder altered the internal structure of the bricks, forming pores during high-temperature firing.

This process, caused by the breakdown of calcium carbonate in the eggshells, helped create a more porous material.

The most significant heat reduction was observed in the bricks containing 10% eggshell waste, with a 50% decrease in thermal conductivity. This indicates that less heat could pass through the material, making it a more effective insulator. The findings suggest that bricks with increased air spaces, due to the eggshell waste, can slow down heat movement, as air is a poor conductor of heat.

The researchers believe that incorporating eggshell waste into construction materials can have a positive impact in hot climates, where buildings absorb and transfer heat from the outside into indoor spaces.

Moreover, the study points to a potential solution for the growing problem of eggshell waste. Currently, an estimated 110 billion eggshells end up in landfills worldwide. By recycling these shells into construction materials, researchers suggest that they can find a useful purpose while also reducing the demand for some raw materials.