An optimal climate-adaptable hydrogel-filled smart window for the energy-saving built environment

Abstract

It is highly desirable to secure the net-zero targets by employing sustainable building materials that can store and release their energy depending on the weather. Conspicuously, windows can play a pivotal role in controlling the energy used in the building by reducing the use of energy-consuming areas that devour massive energy for air conditioning or heating appliances. Presently, the comfort performance of window materials is reaching its storage and processing limit, causing a significant push to find smart materials that can be used in the next generation of the built environment. An innovative solution for sustainable glazing has established an understanding of pH-temperature-transparency modulation. This work uses a hydroxypropyl cellulose and polyacrylic acid-based hydrogel as a rational energy stimulus for double-glazed windows, enriching a comfortable indoor daylight environment without sacrificing aesthetic appeal. The hydrogel maintains thermal comfort across various outdoor temperatures from 4 °C to 60 °C. The developed hydrogel-filled prototype glazing's indoor thermal comfort performance and durability were analsyzed, where the hydrogel intermolecular gap and porosity play a pivotal role across various pHs.