Design parameters influencing the energy performance and indoor comfort of net zero energy building "NZEB" designed for semi-arid urban areas: Digital workflow methodology, sensitivity analysis and comparative assessment

In order to reach carbon neutrality targets in the built environment, worldwide designers should look toward more sustainable buildings, especially with solar integrated configurations to reduce the reliance on conventional sources of energy in urban environments. In this paper, a parametric digital workflow developed in the Grasshopper environment allowed the evaluation of the energy performance and indoor thermal and visual comforts of variable nearly Zero Energy office building configurations. More specifically, as a first step, this paper focused on the use of the global sensitivity analysis tool to evaluate the varying influence of different selected design variables on energy self-sufficiency and indoor thermal comfort of the office building. Then, based on the results of this investigation, we compared the energy performance of nearly/Net Zero Energy Buildings (ZEB) considering two opposing extreme design options, that are the worst and best configurations, using different timescales, i.e., annual, monthly, weekly, daily and hourly performances. Interestingly, the annual Solar Contribution Ratio (SCR), defined as the ratio between yearly solar production and the energy demand of the building, varies between 39 % and 146 %, while also maintaining an acceptable degree of visual indoor comfort (sDA > 0.5). Besides, the findings underscore the significant contribution of the BIPV system in shifting towards the net zero energy goal, accounting for as much as 57.14 % of the total solar energy output. Moreover, the energy self-sufficiency on an hourly basis reveals that the BIPV shading area enhances the daily load cover factor by a range of 4.39 % to 23.87 %, depending on the building's design strategies and the season of the year. Overall, the research outcomes aim at evaluating the influence of a set of design inputs on quantitative indicators related to indoor visual, thermal comforts and energy performance that can provide practical information for building designers, urban planners as well as grid designers and operators. Also, this research provides understandable visual and graphical representations capturing the variation of the indexes in variable time-steps. Lastly, the result of this study proves that Net Zero Energy Building, even positive energy building, could be achievable within semi-arid climate conditions.