A digital workflow to quantify regenerative urban design in the context of a changing climate

The regenerative approach to design goes beyond limiting the environmental impact of the built environment and towards the enrichment of the ecosystem, adaptation to climate change, and the improvement of human health. This concept is being applied to buildings through new standards such as the Living Building Challenge, yet examples of implementation of regenerative design at the urban scale are rare. While this is a promising direction for sustainable design, in theory new metrics, design tools and workflows need to be developed to translate regenerative design concepts into practice effectively. Among other factors, barriers to implementation remain rooted in the shortcomings of existing urban simulation tools to evaluate a wide range of performance metrics simultaneously. This paper thus proposes a prototype workflow to evaluate regenerative performance using existing evaluation tools in a single digital workflow. A series of existing and customised plugins, most of which are already in use and open source, were integrated into a multi-parametric workflow based on the Grasshopper visual programming tool. The workflow was tested on Malaga as a case study and incorporated key performance indicators related to outdoor human thermal comfort, biophilia, daylight performance, and energy use and production, based on data exchange and synergies across the different tools. These indicators were evaluated for present and future climate scenarios obtained from a weather generator. This paper demonstrates the potential of this workflow to receive visual feedback on various aspects of regenerative urban design, thus enabling designers to more effectively pursue an evidence-based urban design process.

Healthy lighting: integrating non-visual responses to light into building simulation

María Lovísa Ámundadóttir

The goal of this thesis is to develop a computer-based lighting simulation framework capable of predicting human non-visual responses to light and to validate novel guidelines that can inform designers about how lighting might affect human non-visual responses in the built environment. The framework consists of four steps, including a mathematical model that accounts for spectral and dynamic variations in light exposure. As a part of the framework, different light exposure patterns are generated to simulate the effects of occupants’ actions, movements, and activities. The results are interpreted based on pre-defined design goals. Light is one of the most significant factors that affect human health and wellbeing in the built environment. Since 2002, when the first reports on the discovery of a novel type of photoreceptor were published, a new field of study started to emerge at the intersection of photobiology and architecture. The novel photoreceptors are the primary mediators of non-visual responses to light in humans, including synchronizing circadian rhythms and directly alerting the brain. These new findings emanating from the photobiology field have sparked a growing interest in the role of lighting design on human health and wellbeing. The novel photoreceptors contain the photopigment meanopsin. Melanopsin is more sensitive to short- wavelength light, with a peak sensitivity that is blue-shifted (λmax ≅ 480 nm), relative to the photopic visual system (λmax ≅ 555 nm), which is dominated by the response of cone photoreceptors. In addition to the difference between the photoreceptors’ spectral sensitivity, researchers have identified intensity, duration/pattern, history, and timing of light exposure as important variables that control the non-visual light response in humans. Considering the blue-shifted sensitivity of the melanopsin-containing photoreceptors, the current recommendations for lighting, which are based mainly on visual criteria, may not provide the necessary amount of light to synchronize important physiological and behavioral rhythms to the 24-hour day. Moreover, a number of recent studies have demonstrated that exposure to bright light can improve alertness, performance, and mood. However, exposures to light at night can disturb circadian rhythms, such as hormone production and sleep-wake cycles, and have been linked to increased risk of cancer. Lighting simulation software tools are designed to evaluate visual requirements and comfort taking into account the stochastic fluctuations linked to the climate and to the behavior of the buildings’ occupants. The evaluation compares simulated light intensity values on a horizontal plane with static threshold values. Since the non-visual system responds slowly to light exposure and adapts to changes in light intensity and spectral composition over much longer time periods than the visual system, the lighting simulation software tools cannot be applied directly to evaluate the non-visual response to light. The response must be evaluated based on dynamic threshold values, which depend on intensity, spectrum, duration, history, and timing of light exposure. Currently, there is no mathematical model that incorporates all five variables to predict the non-visual effects of light on humans. Further, the movements of humans must be simulated to account for the amount of light received at the eye. Thus horizontal sensors on a plane must be replaced with vertical sensors at the eye level that can rotate and move around. The importance of building simulations is growing with increasing complexity of building design and higher performance requirements regarding sustainability. New methods, created at the interface between photobiology and architecture, predicting the non-visual response to light are needed to support design decisions.

2013

Application of the Cradle to Cradle paradigm to a housing unit in Switzerland: Findings from a prototype design

Marilyne Andersen, Shady Galal Mohamed Attia, Jean François Bernard Beney

The Cradle to Cradle (C2C) paradigm is emerging as an important regenerative design approach. C2C is aiming to create a positive footprint of the built environment, beyond carbon neutrality. However, there are very few studies that address the application of the C2C concept in building design. More importantly, there is hardly any documentation processes on methods or tools currently being used to design and evaluate C2C buildings. Therefore, the purpose of this paper is to design, model and assess a C2C building prototype with a focus on energy and materials. The research methodology is based on literature review, case study design and performance (energy/materials) evaluation (DesignBuilder/SimaPro). The paper articulates the values, principles and goals of the C2C paradigm and translates them through the prototype design in the Swiss context. The results of the prototype design point to a 74% independence from non-renewable energy resources, compensating the operating and embodied energy during the building’s life. On the other hand only 8% of the building materials were totally recyclable according to the C2C principles. The design process delivers insights on the application of the C2C concept in the built environment reporting on the limitation and means of improvement.

2013

Light-driven model for identifying indicators of non-visual health potential in the built environment

María Lovísa Ámundadóttir

This thesis introduces a new approach to characterize and evaluate ocular light exposure based on the discovery of novel blue light-sensitive photoreceptors in the human eye. These photoreceptors are the primary mediators of 'non-visual' responses impacting human health, from resetting the circadian clock to directly alerting the brain. In recent years, studies have found that light at short-wavelengths is more effective than light at longer wavelengths at inducing and suppressing a range of 'non-visual' responses. Although it has been recommended that we approximate the spectral sensitivity of these novel photoreceptors with an action spectra peaking near 490 nm, the optimal approach for quantifying non-visual spectral effectiveness is yet unknown. These novel photoreceptors, in addition being photoreceptors themselves, receive inputs from the classical photoreceptors (rods and cones) that in return affect the overall spectral sensitivity of the non-visual system as it changes with lighting conditions. Due to this time-varying spectral sensitivity and the relatively slow temporal processing, the relation between dynamic external light stimuli and the magnitude of non-visual responses cannot be explained with a single function or a simple threshold value. To better understand these non-linear and unknown relations, this thesis aims to develop a novel computational method, based on recent findings about the 'non-visual' - also called non-image-forming - effects of light on human health. A dynamic wavelength-dependent model framework is proposed to evaluate the non-visual health potential of light. This novel approach integrates the spectral effectiveness of irradiation and accommodates time-varying spectral sensitivity functions. These time series of light quantities serve as inputs for the light-driven model, which accounts for light intensity, duration, history, and timing of light exposure. By quantifying light in terms of spectral effectiveness and temporal dynamics, different light exposure patterns can be ranked in terms of its potential to have an impact on human health. The final objective of this thesis is to support the design of healthier buildings by applying evidence-based lighting criteria, which can then inform architectural design through a simulation-based approach. Incorporating non-visual effects into a building simulation workflow requires a good approximation of daylight spectra as it varies with sun position and sky type. Performance predictions must also account for occupant behavior and scheduling, which brings us to the question: How can we apply such a method to make informed decisions about our built environment? The integration of the proposed model into a functional simulation workflow is demonstrated using an architectural case study but first the non-visual spectral effectiveness of light will be evaluated under varying sky conditions to analyze the model output sensitivity to input accuracy. The model and its application to the built environment will then be investigated using multiple view directions and by considering occupant behavior and scheduling to make an immersive prediction within a space. This novel computational approach can be seen as a first step towards human-centric lighting application, simulating an occupant's light consumption to evaluate non-visual health potential that can support decision-making in the built environment.

EPFL2016

Healthy lighting: integrating non-visual responses to light into building simulation

María Lovísa Ámundadóttir

2013

Light-driven model for identifying indicators of non-visual health potential in the built environment

María Lovísa Ámundadóttir

EPFL2016