Complex fenestration systems: towards product ratings for indoor environment quality (original) (raw)
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A comprehensive approach for determining performance metrics for complex fenestration systems
The selection of a fenestration system for a building is critical, as it impacts energy performance, occupant comfort, and ambiance of a space. Complex Fenestration Systems (CFS) address these criteria using a wide variety of novel technologies but are difficult to define or be characterized. Existing metrics for fenestration systems are unable to reveal the dynamics or degree of variety over climate conditions or time of year that define CFS because they rely on a single and arbitrarily-defined set of environmental conditions to calculate. Although the optical characteristics of a CFS can be predicted using its Bi-Directional Transmission Distribution Function (BTDF)a mathematical dataset that describes the angular distribution of light flux as it passes through a materialthis information is too abstract to be meaningful to the building industry. A set of metrics that uses the BTDF in an intuitive way could allow the performance and physical characteristics of these technologies to become more accessible, ultimately allowing the various benefits of daylighting to be realized. The proposed approach offers a solution to this problem by using an annual climate-based methodology to provide a comprehensive evaluation of a system by incorporating three of the most relevant performance aspects: energy efficiency, occupant visual comfort, and ability to view through. Three metrics, the Relative Energy Impact (REI), the Extent of Comfortable Daylight (ECD), anhd the View Through Potential (VTP), were derived from these three criteria to express, in relative terms, a façade's contribution to building energy use, the fraction of time and space for which it achieves comfortable daylight conditions, and the degree of transparency as it relates to an occupant's view through the façade, respectively. These metrics are intended to exist as a mechanism by which manufacturers can evaluate and compare façade systems, provide high-level intuition of relative performance for designers and contractors, and enable the balance of performance objectives based on user preference. In order to successfully implement these metrics, a simple and repeatable calculation process was identified first through a series of sensitivity analyses compromising on relevance or accuracy, and then by defining input conditions that are able to reduce calculation or simulation time substantially. Using both approaches, each of these metrics was further and applied to five sample façades that cover a broad range of Complex Fenestration System types, including a validation study for the VTP metric. A visual representation of this information in a condensed format was then investigated so as to allow straightforward comparisons amongst systems and a synthetic understanding of their performance. A graphical, label-like structure could indeed provide an initial suggestion for the use of these metrics in the rating and standard-setting environments.
Comprehensive performance metrics for Complex Fenestration Systems using a relative approach
Buildings account for over 40% of the energy consumption in the United States, nearly 40% of which is attributed to lighting. The selection of a fenestration system for a building is a critical decision as it offsets electric lighting use as well as impacts energy performance through heating and cooling systems. Further, the fenestration system contributes to both occupant comfort and ambiance of the space. Complex Fenestration Systems (CFS) address these factors with a variety of innovative technologies but the language to describe, discuss, and compare them does not exist. Existing traditional metrics for fenestration systems are unable to reveal the benefits that characterize complex fenestration systems because they are rigid, do not reflect annual performance, and were developed for a different purpose. The framework presented in this research offers a solution to this problem by using an annual climatebased methodology to provide a comprehensive evaluation of a system by incorporating three of the most relevant performance aspects: energy efficiency, occupant visual comfort, and ability to view through. Three metrics, the Relative Energy Impact (REI), the Extent of Comfortable Daylight (ECD), and the View Through Potential (VTP), were derived from these three criteria to express, in relative terms, a façade's contribution to building energy use, comfortable daylight conditions, and the degree of transparency, respectively. Several practical matters were considered when developing a policy-relevant set of metrics, including both ease of calculation for manufacturers and usability for consumers. As such, the calculation methodology evolved from its initial proposal into a simplified approach, analytical where possible, and into a label-like concept for visual representation. These metrics are intended to exist as a mechanism by which manufacturers can evaluate and compare façade systems, provide high-level intuition of relative performance for designers and contractors, and enable the balance of performance objectives based on user preference. Ultimately, the creation of this comprehensive language is intended to stimulate innovation in fenestration systems and encourage their use in both new and retrofit building applications.
A comprehensive method to determine performance metrics for complex fenestration systems
27th Conference on Passive and Low …, 2011
The ability to accurately and concisely describe the performance of complex fenestration systems (CFS) is essential to their effective implementation into the building industry. CFS are a diverse category of daylighting technologies that manipulate the light that is permitted to enter a building space. The variety and degree of dynamics that exist in the range of such technologies require a robust and flexible set of metrics that can communicate performance simply and informatively. This paper presents an approach for processing their detailed optical properties-expressed as Bi-Directional Transmission Functions (BTDF)-into a comprehensible set of metrics that can convey useful information about a system's adherence to visual comfort and energyefficiency objectives. These metrics can then inform non-technical members of the building industry about the performance capabilities of a façade. This paper describes the novel method by which performance is evaluated, accounting for spatial and temporal variation in environmental condition.
Lighting characteristics of complex fenestration systems
The need for energy conservation in buildings has spurred innovations in window technologies. These products include windows combined with shading devices, and windows featuring complex glazings such as smart glazings, translucent and transparent insulation, patterned or decorative glass. Unfortunately, little is known about their impact on the quality of the indoor environment. This paper addresses the development of new lighting quality indices for the outdoor view (which gives a feeling of connection to the outside), indoor view (which may affect feelings of privacy), and window luminance (which indicates the potential risk of discomfort glare). The new indices were applied to a typical fenestration system, consisting of a clear window equiped with an interior perforated shading screen with opaque and translucent materials. The simulation results indicate that the the light-coloured screen has a significant impact on the outdoor view and window's luminance, depending greatly ...
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.
M4.1: Analysis of calculation approaches for complex fenestration systems
2019
FACEcamp, M4.1 Analysis of calculation approaches for complex fenestration systems 2/17 Table of Contents 1 Introduction Objectives 3 Methodology 4 Results 4.1 Simulation tools matrix 4.2 1D simulation toolchains 4.2.1 Toolchain 1 and 2: tool comparison for a coupled thermal and daylight evaluation 8 4.2.2 Toolchain 3: Simplified modelling tool DALEC for early-design evaluation 10 4.2.3 Modelling Non-visual effects of daylight 11 4.3 2D and 3D analysis of CFS 4.3.1 CFD+Radiance approach versus WINDOW 7 in stationary conditions 13 4.3.2 CFD+Radiance approach versus TRNSYS 18 in dynamic conditions 13 4.3.3 CFD+Radiance approach versus in-situ measurements in dynamic conditions 13 5 Conclusions 6 References FACEcamp partners FACEcamp, M4.1 Analysis of calculation approaches for complex fenestration systems 3/17
Zenodo (CERN European Organization for Nuclear Research), 2022
The paper is developed to assess various glass type and their effect on building energy. Consumption. The research will help to understand the effect of types of glass considering its parameters which are VLT (visual light transmit) and SHGC (solar heat gain coefficient). The analysis is done to see effect on energy consumption by changing glass type firm single to double to triple glazing. The analysis is done with the help of BIM software Autodesk Revit with Insight plugin. Use of various types of glass is used. The study is limited to commercial building with G+5 floors located at Ravet. Also, to study varying WWR (window to wall ratio) to varying glass types is done. This paper seeks to integrate the use of BIM based energy analysis in predicting the energy consumption of a Library building.
2016
Energy saving seems to be the basic concept for a sustainable future. To reach the primary goal we need a responsible integration and synergistic collaboration between innovation, advanced technologies and design of the building envelopes. In the field of advanced technologies, Electrochromic glass is one of the most innovative components. These are able to modify on command its own optical features, modifying the level of screening of solar and visible radiation. On this trend, the research group went more in depth on the subject related to the heat transmission of irradiation trough glass surface. The data collected, during the four years of experimenting on the two test rooms, allows us to get interesting and significant elements of evaluation. These elements are oriented towards the project of new building and to existing building heritage with special reference to the areas with an intense and prolonged sunshine. During the research our work has been diversifying in two differe...
On the global performance of offices with different Complex Fenestration Systems (CFSs)
2017
Complex fenestration systems influence indoor comfort conditions and energy consumption in a complex way. If all the involved aspects are not considered jointly since the design phase, buildings can show a deep gap between their planned and real performance, especially when dealing with low energy buildings (Vanhoutteghem et al., 2015). This can be avoided by identifying the design configurations able to provide a trade-off between contrasting requisites: improving comfort conditions while minimizing energy use. This work analyzes and compares different design solutions for an open space office from a global performance perspective. Dependence on the building characteristics and operation strategy has been assessed by comparing two different windows sizes, three glazing systems, and three different approaches to control the shading devices, for a South oriented façade in the climate of Rome. The study has been conducted combining a RADIANCE/DAYSIM lighting simulation with EnergyPlus...