Impact of Climate Change on High-Performance Belgian Houses: Thermal Comfort, HVAC Energy Performance, and HVAC GHG Emissions

Climate change arising from natural and anthropogenic sources affects the built environment in several ways. One of the major impacts of climate change is the increase in average air temperatures that can lead to more intense, severe, and prolonged heatwaves. This study is developed to project the effect of such warming weather conditions on Belgian high-performance houses and provide an idea of mitigation strategies. The study consists of three main parts (Part I, Part II, and Part III). In Part I, the study investigates a large number of thermal comfort/overheating evaluation methods to find a fit-to-purpose and appropriate method. It then provides a critical and qualitative review of resilient cooling strategies that can be applied as mitigation strategies. In Part II, a comprehensive simulation-based methodological framework is introduced to assess and compare the resistivity of buildings and their cooling strategies to the overheating impact of climate change. This part also provides an extensive weather dataset to estimate the changes in weather conditions and heatwaves in Belgium by the end of the century under different emission scenarios. In Part III, numerical studies are performed to predict the changes in thermal comfort conditions, HVAC energy performance, and HVAC Greenhouse Gas (GHG) emissions in Belgian high-performance houses due to climate change. This part includes the evaluation of a set of active and passive cooling strategies based on uncertainty analysis, sensitivity analysis, and optimization techniques. Some of the key findings of this study are (i) current building policies and regulations in the region fail to quantify overheating in the context of climate change accurately, (ii) a heating-dominated region like Belgium is expected to become a cooling-dominated one by the end of the century, (iii) replacement of traditional HVAC systems with more efficient ones (e.g., reversible air-to-water heat pump) has a potential of reducing HVAC primary energy use and HVAC GHG emissions up to 13% and 27%, respectively, (iv) passive cooling design strategies, such as natural ventilation, lowering infiltration rates, insulation, use of thermal mass, green roof, and shading devices are highly effective in achieving comfort and energy efficiency benefits, and (v) the use of active cooling systems to deal with more severe heatwaves will become inexorable in the coming decades. Overall, climate change is a global concern. Governments and policymakers must react swiftly by encouraging proactive adaptation to limit its unfavorable consequences. This can be achieved by establishing a clear path for well-adapted building stock with quantitative targets backed up with appropriate inspection, enforcement, and access to finance.