Energy sustainability study, and indoor air quality, iaq, for health and thermal confort between two classroom buildings of a campus, (standard building and near zero energy building ,nZEB )

This doctoral research investigates how nearly zero-energy buildings (nZEB) can curb the European Union’s building-sector footprint, which currently represents about 40% of total energy consumption, more than 30% of electricity use, and roughly 36% of greenhouse-gas emissions. The case study is INDUVA, an advanced nZEB lecture building on the University of Valladolid (UVa) campus in Spain. The core objective is to quantify how energy-efficiency measures and on-site renewables jointly determine energy demand, primary energy use (renewable and non-renewable), and environmental impacts, while preserving high Indoor Environmental Quality (IEQ). The research evaluates energy intensity for primary, non-renewable, and renewable energy, the performance of HVAC systems, the building’s renewable energy ratio, and its global warming potential (GWP). A rigorous, measurement-informed modeling workflow underpins the analysis. Dynamic simulations are performed in DesignBuilder (version 7) with the EnergyPlus engine to calculate detailed energy balances for heating, ventilation, air conditioning, and lighting. Models are calibrated against continuous monitoring data from INDUVA’s Building Management System (BMS), which captures multiple physical variables and end-use consumptions. This calibration enables reliable evaluation of key performance indicators and strengthens the link between simulated and real-world operation. An important contribution is the holistic characterization of INDUVA’s envelope, systems, and controls. The building deploys state-of-the-art mechanical ventilation to assure high indoor air quality (IAQ), roof-mounted photovoltaic (PV) panels for electricity generation, a geothermal heat-recovery strategy that leverages ventilation air, and connection to a biomass-fired district heating network. The BMS orchestrates these subsystems to optimize environmental conditions and energy use. Its high-resolution data stream supports both rigorous model calibration and ongoing operational tuning. To assess future robustness, the research explores climate-change impacts and climatic transferability. Using CCWorldWeatherGen, current weather files are morphed to represent scenarios from 2022 to 2080. The building is then re-simulated across these horizons to quantify how warming affects loads, energy use, and associated CO₂ emissions. A relocation study further evaluates performance in contrasted climates—Juneau and Warsaw—revealing sensitivity to local weather patterns and informing the adaptability of nZEB strategies across different contexts. The scope extends beyond energy to a comprehensive IEQ assessment. Indoor air quality, thermal comfort, ventilation effectiveness, lighting and daylight access, and acoustics are benchmarked against international standards, providing an integrated view of occupant-centric performance. This dual focus demonstrates that nZEBs must be engineered not only for low energy and emissions but also for consistently healthy and comfortable indoor conditions throughout the year. Findings reveal a clear temporal shift driven by climate change: heating demand declines, yet cooling energy requirements and related CO₂ emissions increase. This asymmetry underscores the need for adaptive design strategies such as enhanced passive cooling, dynamic solar control, high-efficiency heat-rejection systems, and resilient control logic to preserve low-carbon outcomes as summers intensify. Results also indicate that maintaining high IAQ through mechanical ventilation is compatible with energy efficiency when heat recovery, demand-controlled ventilation, and intelligent scheduling are applied. Finally, a comparative analysis contrasts INDUVA with a conventional lecture building on the same campus. The comparison isolates the nZEB features that deliver the largest benefits—superior envelope performance, integrated renewable generation, advanced HVAC with heat recovery, and BMS-guided operation—while highlighting practical challenges in scaling these solutions to the existing building stock that requires energetic rehabilitation. Overall, the study provides evidence-based guidance for designers, facility managers, and policy-makers: nZEB principles can deliver substantial energy and emissions reductions without compromising IEQ, but future-proofing against warmer climates demands thoughtful emphasis on cooling resilience, flexible controls, and context-specific renewable integration.