Dong Wang

This study presents a bibliometric and systematic review of 480 articles meeting the following inclusion criteria: English-language articles, reviews, or proceeding papers focusing on building topics with full text available, retrieved from the Web of Science Core Collection on 9 Jannary 2026 to map the intellectual landscape of smart-sustainable building (SSB) research. Employing the PRISMA framework combined with scientometric mapping (VOSviewer), thematic classification, and qualitative synthesis (no risk of bias assessment was performed as this was a bibliometric review), the analysis reveals exponential publication growth since 2022, identifying three dominant thematic clusters: digital enabling technologies (41.0%), energy systems (30.8%), and advanced building envelopes and materials (28.3%). Keyword analysis identifies “smart buildings,” “green buildings,” and “energy efficiency” as central conceptual anchors, while temporal trends indicate increasing attention to artificial intelligence, digital twins, and blockchain. Notably, 51.4% of articles address two or more themes simultaneously, confirming the field’s interdisciplinary character. Critical analysis reveals persistent fragmentation: sustainable building rating tools (e.g., BREEAM, LEED) and smart building evaluation methods (e.g., Smart Readiness Indicator). Seven challenges, including assessment fragmentation, high costs, and cybersecurity vulnerabilities, are identified as barriers to SSB adoption. Limitations include reliance on a single database (Web of Science) and subjective thematic classification. This review provides a roadmap for future research emphasizing integrated assessment frameworks and interdisciplinary collaboration. Registration: Not pre-registered. Funding: National Key R&D Program of China (2025YFF0521003).

Rotary gas-gas heat exchangers (GGHs) are pivotal for waste heat recovery in low- and medium-temperature denitrification systems of cement kilns. This study examines the performance of GGHs within such systems by coupling computational fluid dynamics (CFD) with the response surface method (RSM), introducing overall system performance (OSP) as the principal optimization criterion. The investigation systematically elucidates the effects of treated flue gas inlet temperature, inlet velocity, and rotor speed on GGH efficiency. Findings reveal that OSP increases with rotor speed but reaches a plateau beyond 1 rpm; it decreases with higher inlet velocity and increases with higher inlet temperature. Response surface analysis identifies treated flue gas inlet temperature as the most influential parameter, highlighting a synergistic effect between rotor speed and inlet temperature, alongside an antagonistic interaction between inlet temperature and inlet velocity. To ensure safe system operation, engineering constraints were incorporated into the optimization framework using a Box-Behnken design. The optimal operational parameters were determined as a treated flue gas inlet temperature of 250°C, inlet velocity of 8 m/s, and rotor speed of 1 rpm, yielding a maximum OSP of 107.74. The integrated CFD-RSM methodology and constraint-aware optimization strategy presented in this study offer a practical reference for enhancing the operational efficiency of industrial waste heat recovery systems, particularly in cement kiln SCR applications.

The building sector holds a significant position in the global energy consumption share, and its environmental impact continues to intensify, making the construction industry a key player in sustainable development. The application of life cycle assessment on buildings (LCA-B) is widely employed to evaluate building energy and environment performance, and thus is of great significance for ensuring the sustainability of the project. This work aims to provide a systematic overview of LCA-B development based on reviewed literature. A three-stage mixed research method is adopted in this study: Firstly, an overall analysis framework is constructed, and 327 papers related to building life cycle assessment published between 2009 and 2025 are screened out by using the bibliometric method; Then, through scientometrics analysis, the journal regions, sources, scholars, and keyword evolution are revealed and analyzed using VOSviewer tool, and the hotspots in the field of LCA-B (e.g., integration of building information modeling (BIM) in LCA-B, multi-dimensional framework of environment–society–culture) are preliminarily explored based on the selected highly cited papers. The research finds that: (1) the performance of low energy buildings is better than that of net zero energy buildings from the perspective of LCA; (2) software compatibility and data exchange are the main obstacles in the integration of BIM-LCA; (3) a multi-dimensional LCA framework covering the social or cultural aspects is expected for a comprehensive assessment of building performance. This study provides a systematic analysis and elaboration of review articles related to LCA-B and thereby provides researchers with in-depth insight into this field.

In this paper, a novel central air-conditioning system with an internal heat exchanger is proposed and analyzed for its energy-saving effect. Two frequently used systems are chosen as the reference systems, i.e., a conventional system with a sensible heat exchanger (Reference System I) and a conventional system with a total heat exchanger (Reference System II). Analysis models are built to simulate the performance of the system. The energy-saving effects of the proposed system and the two reference systems under different conditions are theoretically calculated using a case-studied shopping mall in Nanjing, China. The results show that the influence of indoor relative humidity (RH) on the energy-saving effect is much greater than that of the indoor design temperature. Indoor design parameters have a greater impact on energy saving than outdoor design parameters. Under the studied conditions, the maximum energy-saving rates of the proposed system, Reference System I, and Reference System II, are 52.7%, 2.3%, and 12.1%, respectively. With the decrease in fresh-air ratio from 70% to 20%, the difference in energy-saving rates between the proposed system and Reference System II (Reference System I) can increase from 5% to 23% (15% to 30%). Therefore, the proposed system has obvious energy-saving potential and advantage, especially under the condition of a lower fresh-air ratio.

In order to improve the application possibility of CO₂/R41 azeotropy mixture in the refrigeration industry, the optimum mass ratio of composition is defined and determined according to the thermodynamic properties and safety. On the basis of the first and second laws of thermodynamics, a model is proposed to evaluate the performance of CO₂/R41 single-stage transcritical cycle (CO₂/R41 cycle) in which a throttling valve is integrated and CO₂/R41 azeotropy refrigerant is adopted. The performance of CO₂/R41 cycle at the optimum mass ratio of CO₂/R41 azeotropy mixture is then compared with that of a CO₂ two-stage transcritical cycle with throttling valve (CO₂ two-stage cycle) and that of a CO₂ single-stage transcritical cycle with expander (CO₂ expander cycle). The results show that the optimum mass ratio of CO₂/R41 azeotropy mixture is 0.583/0.417. Compared with CO₂ two-stage cycle and CO₂ expander cycle, CO₂/R41 cycle has the advantages of a simpler structure, lower optimum high pressure, appropriate discharge temperature of the compressor, and higher COP. Therefore, the CO₂/R41 azeotropy mixture with the mass ratio of 0.583/0.417 is eco-friendly and can be considered as a good alternative refrigerant for application in the refrigeration industry. The simple CO₂/R41 cycle shows great feasibility to replace the complex CO₂ two-stage cycle and CO₂ expander cycle.