Energy retrofits for smart and connected communities: Scopes and technologies

The trajectory of sustainable urban development evolves with the integration of intelligent technologies, extending beyond individual buildings to encompass entire communities interwoven with smart systems. Energy retrofits at smart and connected communities are crucial for sustainable urban renewal, yet they present distinct challenges from individual home retrofitting. However, a comprehensive understanding of the emerging research scopes and technologies in large-scale energy retrofits is lacking. To address this problem, this research systematically reviews journal publications in this field from 2000 to 2023. Results disclose four research scopes: building construction, mechanical systems and equipment, electrical systems and computing, and human-centered design and connectivity, suggesting a new landscape for energy retrofit research, which largely extends beyond the traditional field of the built environment (e.g., heating, cooling, lighting, and structure) to advanced computing, renewable energy, and human-centered connectivity. Results also delineate a new paradigm of retrofit technologies with three focused areas: within-building optimizations (heating and air conditioning, envelope, engineering design, and smart technology), between-building connections (power grid, district energy, and integrated energy system), and whole-community integrations. They represent the nodes, ties, and interplay within community networks. Eight retrofit focuses and their specific technologies and computational techniques are summarized and examined. Notably, the approach of simulation and computational modeling is prevalent, with evolutionary algorithms featured in computational techniques. The review suggests five gaps and proposes a roadmap to advance future research in energy retrofits, specifically emphasizing the integration of intelligent technologies and multidisciplinary collaborations.