📘 Publication: Night Ventilation Under Heat Waves in Office Buildings

Buildings continue to struggle during heat waves, while cities experience hotter nights and reduced cooling capacity.

This study evaluates whether night ventilation can truly mitigate overheating during extreme heat events. The article, published in the Journal of Building Engineering, combines measured urban and rural climate data with calibrated building energy modeling to assess the performance of natural and mechanical night ventilation in a nearly zero-energy office building in Brussels.

Amaripadath, Riccardo Paolini, David J. Sailor, Shady Attia (2023) Comparative assessment of night ventilation performance in a nearly zero-energy office building during heat waves in Brussels. Journal of Building Engineering, 78, 107611. 🔓 Open access: https://orbi.uliege.be/handle/2268/305891

Key findings

• Natural night ventilation reduces overheating during heat waves by up to 0.50 °C

• Urban microclimates significantly penalize night cooling performance

• Mechanical night ventilation increases cooling energy demand due to fan operation

• Time-integrated overheating indicators outperform peak metrics

• Model calibration (ASHRAE Guideline 14) is essential for credible conclusions

🔧 Why This Matters

Night ventilation is often promoted as a low-cost passive cooling solution. This paper shows when it works, when it fails, and why. In dense cities, rising nighttime temperatures, reduced wind speeds, and urban heat islands limit the effectiveness of nighttime cooling. Yet, when properly designed, calibrated, and combined with active cooling, natural night ventilation remains a powerful strategy for:

1. reducing overheating risk 🌡️

2. lowering cooling energy demand ⚡

3. improving resilience during heat waves 🏙️

These findings directly support climate-adaptive design, awareness of outdoor microclimates, and evidence-based cooling strategies for nearly zero-energy buildings.

🙏 With thanks to MK Engineering for technical support and collaboration.

📌 Read the article: https://orbi.uliege.be/handle/2268/305891

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#NightVentilation #UrbanHeatIsland #HeatWaves #Microclimate #BuildingPhysics #ThermalComfort #ClimateResilience #EnergyModeling #Calibration