Robust net-zero energy buildings: a methodology for designers to evaluate robustness

The European energy performance of the buildings directive (EPBD) recast states that all new buildings should be nearly zero energy from 2020. Nearly zero energy buildings can be achieved by improving building insulation levels, using energy efficient technologies and integrating renewable energy systems into the built environment. Considering the high economic efforts required for the implementation of these measures in the built environment, it is important to ensure that these measures deliver the desired performance over the building’s life span. However, many uncertainties arise in the operation of a building such as household size and their corresponding behavior. In addition, external factors, such as climate change and policy changes affect the building’s performance over its life-span. These uncertainties impact the building’s performance, resulting in possible performance deviation between the predicted performance in the design phase and the actual performance during operation. To reduce this performance deviation, performance robustness of these buildings considering uncertainties should be assessed in the design phase. Hence, we developed a computational methodology considering these uncertainties to assess the performance robustness of net-zero energy buildings. The developed methodology is generic and can be used for performance robustness assessment of both new buildings and renovations. This methodology is useful when different stakeholders with multiple performance requirements are involved in a project, and it is also effective in identifying a robust design from a large design space. Due to space constraints, this article demonstrates how a designer can use this methodology to identify robust net-zero energy building designs among only few design alternatives. This demonstration is carried out for the policymaker and the homeowner, who represent different interests in the building industry.