Sensitivity analysis for energy modelling based on daylight simulations

Abdelwahab, Sahar; Rutherford, Peter; Kent, Michael G.; Altomonte, Sergio

Abstract

Simulation techniques for modelling the lighting and energy performance of buildings are becoming widely available. Previous research by the authors found the outcomes of lighting simulation to be substantively influenced by individual settings of various model parameters (e.g., ambient reflections and grid size), particularly for complex façades. This study postulates that this influence is also reflected on predicted energy consumptions since daylight availability affects the artificial lighting needed to meet illuminance targets and the heat transferred from the façade. To test this hypothesis, a sensitivity analysis was performed investigating the influence of various daylight simulation settings on predicted energy loads. The sensitivity analysis was based on annual simulations using a shoebox model with simple and complex façade configurations under Cairo and Nottingham climates. Daylight simulations were conducted using RADIANCE while energy analysis was run through EnergyPlus. The results were statistically analysed for annual cooling, heating, lighting and total energy loads. The analysis showed that fast-low precision daylight simulation settings of ambient reflections overestimated lighting and cooling energy loads, and underestimated heating requirements. The differences were statistically and practically significant particularly in terms of lighting loads. The results were largely dependent on climatic conditions, and the differences consistently increased in case of complex façade systems. The findings from this study are discussed in the context of the challenges that façade designers need to tackle when using simulation tools at early design stage towards obtaining plausible performance outcomes.

Citation

Abdelwahab, S., Rutherford, P., Kent, M. G., & Altomonte, S. (2018). Sensitivity analysis for energy modelling based on daylight simulations. In International Conference for Sustainable Design of the Built Environment: SDBE 2018: Proceedings. , (49-60)

• Conference Name: International Conference for Sustainable Design of the Built Environment (SDBE 2018)
• Start Date: Sep 12, 2018
• End Date: Sep 13, 2018
• Acceptance Date: Jul 15, 2018
• Publication Date: Sep 12, 2018
• Deposit Date: Sep 21, 2018
• Publicly Available Date: Sep 21, 2018
• Pages: 49-60
• Book Title: International Conference for Sustainable Design of the Built Environment: SDBE 2018: Proceedings
• ISBN: 9781999797195
• Keywords: Daylight; Energy; Simulation; Sensitivity; RADIANCE
• Public URL: https://nottingham-repository.worktribe.com/output/1098011
• Publisher URL: http://newton-sdbe.uk/conferences/sdbe-2018/