I-Corps: Microencapsulation of phase change materials using cenospheres for thermal energy efficiency in building materials

The broader impact/commercial potential of this I-Corps project is the development of microencapsulated phase change building materials for temperature management and energy efficiency. Residential and commercial buildings account for about 75% of all electricity use in the US and result in an energy costs that totaled over $410 billion in 2020. The proposed microcapsule technology may be integrated into building materials to improve US energy efficiency up to 20%.

This reduction in energy use could lead to $82B savings per year. In addition, the proposed technology may be used in a broad array of building materials including wallboards (e.g., drywall, gypsum boards, acoustical panels, and fire-retardant panels), machine applied plasters, ceiling products, flooring products, dry mortar, cement mixtures, and interior and exterior coatings.

This I-Corps project is based on the development of a microencapsulation technology for phase change materials (PCMs) using cenospheres to improve energy efficiency in building materials. In existing technologies, PCMs are microencapsulated by synthesizing a polymer shell on the surface of PCM droplets. This type of shell is expensive and has limited stiffness/strength, low thermal and chemical stability, high flammability, and low thermal conductivity.

The proposed technology addresses these problems by using cenopheres as the shell material. Cenospheres are hollow fly ash particles generated in coal burning power plants. Cenospheres inherently have small pores that are sealed by a thin glass-crystalline film.

By removing this film through chemical etching, the pores may be exposed, providing a path for PCMs to enter the internal void of the cenosphere. Once filled, a thin coating is then applied on the PCM-impregnated cenospheres to prevent the possible leaking of liquid PCMs. Compared with existing products, the proposed PCM microcapsules have been shown to be lower cost, stronger, more durable, flame resistant, and higher in thermal conductivity.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.