Streamlining Access to Informative Performance Metrics for Complex Fenestration Systems

A mechanism to accurately assess the performance of complex fenestration systems (CFS) is crucial for driving the appropriate adoption of these technologies to improve user comfort and energy use in both new construction and retrofit design. Typically, CFS are not provided sufficient consideration because user intuition is lacking: existing metrics, while valid for conventional systems, fail to reveal the dynamic nature of the performance of CFS. Conducting and reporting elaborate simulation results is neither feasible nor useful for manufacturers and users and thus a comprehensive rating system based on novel performance metrics has been identified as a means to describe CFS. This paper describes the methodology used to determine the simplified calculation procedure for three metrics defined in a previous paper, and the rational for the ultimate decision. The three metrics, the Relative Energy Impact (REI), the Extent of Comfortable Daylight (ECD), and the View-Through Potential (VTP) aim to provide context in three important areas of daylighting technology performance, namely energy efficiency, occupant visual comfort, and view through the facade respectively, such that the user can select systems to address his or her own priorities. Conducting and reporting full resolution calculations for all input conditions would be unfeasible and unwieldy because of the quantity of data that would have to be managed and the effort that would be spent on such en enterprise for every system. A method to eliminate redundancies and minimize the number of input parameters and calculations thus becomes necessary. This paper proposes an approach based on trends, sensitivity analysis, and error minimization techniques and presents the iterative simplifications required to produce the same relative ranking performance of the sample systems as a benchmark analysis would.