Assessing the Performance of a Thermoresponsive Liquid‐Based Smart Windows for Building Thermal Regulation through Outdoor Experimentation and Computational Modeling

• Published in: Advanced sustainable systems (Online) 2024-09, Vol.8 (9), p.n/a
• Main Authors: Parisi, Gregory, Wang, Xuanjie, Hwang, Youngjin, Narayan, Shankar
• Format: Article
• Language: English
• Subjects: building energy modeling; building thermal control; energy saving; Heating Ventilation and Air Conditioning; passive temperature control; smart window; thermal comfort; thermoresponsive window
• ISSN: 2366-7486; 2366-7486
• DOI: 10.1002/adsu.202400237

Smart windows have the potential to respond dynamically and passively to external stimuli, controlling the amount of light passing through the window. When a smart window switches from a clear to a translucent state, energy flow through the window is partially attenuated, allowing a room to cool down passively, thereby reducing the energy and fossil fuel consumption for air conditioning. The smart window demonstrated here consists of a thermoresponsive liquid consisting of Tergitol 15‐S‐7, which can dynamically and passively switch the window's transmittance when a temperature of 39 °C is reached. It is also demonstrated how the transition temperature can be lowered by adding salts. Outdoor experiments in realistic environments show that the temperature of a model house built with a thermo‐responsive window can achieve an indoor temperature of 7 °C less than a control house with an ordinary window. This study quantifies the energy savings possible using such windows at the building scale for cooling and heating in different climates and times of the year. A thermoresponsive smart window dynamically adjusts transparency based on temperature. These windows use a cost‐effective liquid mixture with Tergitol, a common detergent, becoming cloudy as the temperature rises. Tergitol windows reduce energy consumption, limiting the need for air conditioning. Results from testing the window under different conditions are reported to show its effectiveness, while simulations demonstrate significant energy‐saving potential.