Building-Tailored Hierarchical Electrochromism with Optimized Control Strategies

Area of Science:

• Materials Science
• Building Science
• Energy Efficiency

Background:

• Electrochromic smart windows face challenges in material-application integration.
• A building-centric approach is needed to bridge the gap between material capabilities and practical building energy management.

Purpose of the Study:

• To develop a novel multi-band hierarchical material and control strategy for electrochromic devices (ECDs).
• To demonstrate an electrochromic window (ECW) with tunable spectral states for enhanced building energy savings.
• To validate the effectiveness of load-responsive and climate-adaptive control strategies for optimizing ECW performance.

Main Methods:

• Fabrication of an ECD using Prussian blue (PB) with Fe4[Fe(CN)6]3 and Nb18W16O93 film electrodes.
• Implementation of hierarchical regulation via potassium ion shuttling and cation-anion co-intercalation.
• Development and testing of load-responsive and climate-adaptive intelligent control strategies for the ECW.

Main Results:

• The developed ECD enables four spectral customization states: transparent heating, zero-energy bright heating, daylight-preserving bright cooling, and maximum-blocking dark cooling.
• The load-responsive strategy achieved a 25.4% cooling energy reduction by utilizing the zero-energy bright heating state for over 75% of summer operation.
• The climate-adaptive strategy demonstrated location-optimized operation with up to 56.9% summer energy savings, highlighting performance disparities based on control parameters.

Conclusions:

• The dual breakthroughs in multi-band hierarchical material and control strategy establish a scalable path for electrochromic smart window applications in buildings.
• Intelligent control strategies significantly enhance the energy-saving potential of ECWs by embedding tunable spectral control into building energy management.
• This building-centric paradigm effectively bridges the material-application disconnect, paving the way for innovative and energy-efficient smart window technologies.