Analysis of building envelope for energy consumption and indoor comfort in a near-zero-energy building in Northwest China

• The study identifies rock wool insulation as an effective material for reducing energy consumption in cold climates, achieving a specific energy consumption of 10.58 kWh/m²/year. • An optimized window-to-wall ratio significantly improves thermal comfort while reducing energy use, contributing to the building's energy efficiency. • The optimized envelope configuration achieved a specific energy consumption reduction of 10.58 kWh/m²/year, below the 15 kWh/m²/year threshold for nearly zero-energy buildings (NZEBs). • The research provides a detailed simulation and experimental validation for near-zero-energy buildings in northwest China, demonstrating the feasibility of the proposed envelope configurations. • The building incorporates solar photovoltaic power generation systems and low-temperature air-source heat pumps, highlighting the potential for further optimization to fully meet NZEB criteria. This study investigates the influence of building envelopes on energy consumption and indoor comfort in a near-zero-energy building located in northwest China using experimental testing and TRNSYS/CFD simulations. The results indicate that optimized envelope designs, particularly those incorporating rock wool insulation and a suitable window-to-wall ratio, can significantly reduce energy consumption, especially during the heating season, while maintaining indoor thermal comfort. The building's annual heating energy consumption is 10.58 kWh/m²/year, which is below the threshold of 15 kWh/m²/year defined for nearly zero-energy buildings (NZEBs). Further optimization, such as increasing insulation thickness and enhancing renewable energy utilization, is suggested to achieve higher energy efficiency and fully meet the criteria for NZEBs. This study provides valuable insights into energy-efficient envelope design for cold climates and highlights the importance of selecting appropriate materials and configurations to achieve both energy savings and indoor comfort.