‘Smart’ Windows Block Heat, Not Light

A new kind of smart window blocks out heat when the outside temperature rises, potentially reducing the use of air conditioning.

Developed by researchers from several Chinese institutions, the windows turn an opaque white in response to external heat; this prevents heat from entering while still allowing light through. The windows become transparent again as temperatures drop.

Current methods for making smart windows use jelly-like materials called hydrogels that swell in the heat, which hurts performance.

The new smart windows incorporate microscopic hydrogel beads suspended in water and alcohol. Sandwiched between two panes of glass, the solution exhibited less swelling than its predecessors.

The researchers built a model house using the smart windows, and tested their thermosensitive behavior and solar modulation ability using differential scanning calorimetery, UV-VIS-NIR spectrophotometery, dynamic light scattering and rheology.

Research funding came from the National Natural Science Foundation of China, Fundamental Research Funds for the Central Universities, the Higher School Specialized Research Fund and a 111 Project grant.

The work was published in Industrial & Engineering Chemistry Research (doi: 10.1021/ie502828b).