Numerical study on energy, economic and environmental performance of modular pipe-embedded energy walls with thermal diffusion filler cavities

Pipe-embedded energy walls represent a paradigm shift in opaque-envelope design, leveraging low-grade thermal energy to deliver advanced thermal regulation. However, conventional pipe-embedded energy walls (CPEWs) exhibit localized overheating, reducing energy efficiency and economic viability. This study aims to develop modular pipe-embedded energy walls (MPEWs) with thermal-diffusive filler cavities to eliminate heat accumulation and numerically conduct the first comprehensive energy-economic-environmental (3E) performance quantification. A numerical model for MPEW was established and validated, integrating uncertainty analysis (UA) and global sensitivity analysis (GSA) to evaluate impacts of 10 risk parameters across structural, operational, and material categories on eight 3E indices. The UA findings indicate that, with optimized design and operating parameters, MPEWs can significantly reduce the internal surface thermal load of the wall, and even achieve supplemental heating under optimized conditions. GSA identified insulation thickness, pipeline diameter, and control strategy as dominant parameters. The adoption of multi-pulse injection strategies can enhance operating energy efficiency while maintaining equivalent thermal performance under long-term injection strategy. For practical applications, it is recommended to optimize the inlet velocity within the range of 0.2–0.4 m/s, to set the vertical size of the filler cavity between 150–200 mm, and to control the thermal conductivity of the pipe-embedded layer within 1.1–3.1 W/(m·K). A scientific basis is provided for optimizing building envelopes with balanced energy-saving, economic, and environmental outcomes.