J. Alstan Jakubiec

J. Alstan Jakubiec
University of Toronto | U of T · Faculty of Architecture, Landscape and Design

PhD in Building Technology

About

48
Publications
32,188
Reads
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1,502
Citations
Introduction
I work on building performance simulations, post-occupancy evaluations, and the design of climate-responsive & comfortable buildings. My main expertise is in lighting simulation (Radiance-based) and measurement; however, I also spend a significant amount of time developing workflows for comfort and energy using EnergyPlus.

Publications

Publications (48)
Conference Paper
Full-text available
The impact of dynamic landscape elements on daylight and energy is not typically considered in building performance simulations. This paper describes a new method of creating detailed, seasonally varying tree models that integrate gap fraction, seasonal leaf drop, regrowth, and colour change schedules, as well as dimensions and heights of tree cano...
Conference Paper
Full-text available
We demonstrate a case study of Urban Heat Island (UHI) indicators in Toronto, ON, Canada under five climate change scenarios until 2080. We simulated 48,600 UHI predictions by varying nine urban design parameters: building height, site coverage ratio (SCR), façade-to-site ratio (FSR), green coverage ratio (GCR), tree canopy ratio (TCR), building ty...
Conference Paper
Full-text available
We compare a new, novel lighting design workflow based on human photobiology with existing metrics for non-visual lighting design. There are a variety of light simulation methods and a lineage of circadian system biological models, but they are not connected into a cohesive workflow. We applied this novel workflow to two design variables: window sp...
Conference Paper
Full-text available
We assess the state of the art in non-image forming effects (NIF) of light on human health, alertness and wellbeing as applied to the design of the built environment. There are many methods of calculating spectral daylighting weighted for its impact on circadian dynamics and alertness; however, all current analysis is based on a saturation effect....
Article
Full-text available
Typical buildings are static structures, unable to adjust to dynamic temperature and daylight fluctuations. Adaptive facades that are responsive to these unsteady solar conditions can substantially reduce operational energy inefficiencies, indoor heating, cooling, and lighting costs, as well as greenhouse-gas emissions. Inspired by marine organisms...
Chapter
Population growth, urbanization, and related space constraints require new construction and densification of urban centres around the world, including especially sufficient housing for a growing population. The goal of the sustainable design process is the development of buildings that ‘meet the needs of the present without compromising the ability...
Technical Report
Full-text available
This technical report deals with the current state of the art in the field of spectral measurements and models of daylight. The presented document is a result of joint work conducted by members of the IEA SHC Task 61 / EBC Annex 77, Subtask C3. It provides an overview of: (i) daylight sites conducting spectral (radiance, irradiance) measurements (i...
Article
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This article discusses ratings of visual discomfort from glare across different buildings located in Singapore. These data were used to determine if range effects influence the vertical illuminance values for the same ratings of visual discomfort when the category rating procedure is used. The effect occurs when maxima and minima vertical illuminan...
Article
Building facades that can dynamically absorb light in the visible and near-infrared region of the electromagnetic spectrum enable temporally-programmable optical control and improved building energy-efficiency. Conventional solid-phase chromogenic materials suffer performance limitations that might be addressed by highly-mobile, self-assembling, ga...
Article
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This paper presents a field study that explores lighting qualities within higher educational classrooms in Singapore. Eight classrooms of three types—computer labs, collaborative learning spaces and lecture halls—are studied. Lighting simulation models are calibrated and validated by measurements taken onsite and utilized to generate both instantan...
Article
This paper presents a study that investigates lighting qualities within three computer labs from a long-term perspective. Subjective assessments from 173 participants were collected. Accurately calibrated simulation models of three computer labs were generated to simulate annual lighting quantities based on horizontal illuminance (Eh), vertical ill...
Article
Full-text available
In this paper we present a post-occupancy study of 326 participants in 10 daylit office buildings in Singapore and correlate the results with climate-based daylighting metrics (CBDM) and electric lighting simulations using calibrated simulation models of the 10 buildings. For the first time, this study tests CBDMs which are used in building design...
Article
Full-text available
The research community has worked on improving the design, performance, and operation of radiant system technologies; however, the interactions between architectural design decisions and radiant cooling systems design in the tropics – where radiant system design and operation represents a challenge due to high external heat gains and latent loads –...
Article
Full-text available
One challenge when evaluating daylight distribution is dealing with the large amount of temporal and spatial data, visualizations and variability in illuminances that are assessed in buildings. Using a dimensionality reduction method based on principal component analysis, we identified the most representative annual daylight distributions. We model...
Conference Paper
Full-text available
This paper presents a post-occupancy daylighting study within 17 residences in Singapore consisting of 35 participants. Each residence was visited, and a calibrated daylighting model was constructed and validated based upon 100's of individual illuminance measurements. A survey on subjective lighting quality was administered to each participant. Th...
Conference Paper
Full-text available
This paper presents a study that explores instantaneous and long-term lighting design metrics based on subjective evaluations within higher educational buildings in a tropical weather. Three types of classrooms-computer labs, collaborative spaces, and lecture halls-were studied. Lighting simulation models were calibrated and validated using measure...
Conference Paper
Full-text available
Calibrated climate-based lighting simulation models of buildings perform an essential role in post-occupancy evaluations (POE), such as annual frequency assessments of daylighting quality and visual discomfort. However, the role of lighting analysis is temporally limited by instantaneous measurements or limited in scale by requiring constant monito...
Conference Paper
Full-text available
Predicting the urban microclimate using simulation tools can help designers to increase outdoor thermal comfort. This study discusses 4 prediction tools from an urban designer's view regarding their capabilities, limitations, ease of use, and accuracy. ENVI-met, RayMan, SOLWEIG, and STEVE are urban microclimate prediction tools investigated in this...
Conference Paper
Full-text available
The research community has worked on optimizing the design, performance, and operation of radiant system technologies; however, the holistic interactions between architectural design decisions and radiant cooling systems design in the tropics have been left unexplored. Morris sensitivity analysis is used to analyze the design performance impact, in...
Conference Paper
Full-text available
Colours that surround us are not just the result of surface properties, rather the interplay between the spectral distribution of illuminating light and spectrally specific surface reflectance. Despite the temporal and spatial variation of daylight spectral distribution, daylight simulation platforms most commonly use lu-minance based sky models (C...
Article
Full-text available
Calibrated climate-based lighting simulation models of buildings have the capacity to perform an essential role in postoccupancy evaluations, such as annual frequency assessments of daylighting quality and visual discomfort. However, in most postoccupancy case studies the role of lighting analysis is temporally limited by instantaneous measurements...
Conference Paper
Full-text available
This paper presents a post-occupancy study of 543 participants in 10 daylit office buildings in Singapore. Calibrated daylighting and electric lighting simulation models of each building were created and verified. HDR photographs and vertical and horizontal illuminance measurements were taken at each participant's workspace, and a survey on their l...
Conference Paper
Full-text available
Urban settlements require design improvements towards increased comfort and reduced energy consumption through active and passive means to create liveable cities in the future. This study investigates the impact of 6 urban design criteria—building height, plot ratio, greenery, glazing ratio, shading, and materiality—on discrete environmental metric...
Conference Paper
Full-text available
This paper presents a novel study comparing advanced annual visual discomfort calculations to typical illuminance-based overlighting metrics. The Unified Glare Rating (UGR), Daylight Glare Probability (DGP), and simplified Daylight Glare Probability (DGPs) are calculated at an occupant's eye level and are compared to the Useful Daylight Illuminance...
Conference Paper
Full-text available
This paper describes a visualisation framework for organising data outputs generated from a complex multi-objective optimisation design space. The three-part visualisation framework is structured to identify solution clusters along the Pareto front, before providing designers with design space navigation control through genotype value displays. The...
Conference Paper
Full-text available
This paper describes a visualisation framework for organising data outputs generated from a complex multi-objective optimisation design space. The three-part visualisation framework is structured to identify solution clusters along the Pareto front, before providing designers with design space navigation control through genotype value displays. The...
Conference Paper
Full-text available
Singapore is one country that is leading the charge in environmental design in the tropics by advocating for smart strategies in buildings. The small city-state uses Residential Envelope Transmittance Values (RETV) to quantify heat transfer through residential building façades. This study compares simulated performance metrics of ten Singaporean ho...
Conference Paper
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This manuscript describes a methodology for organizing and displaying disparate sources of building performance simulation data to form spatial displays of a myriad of building performance outputs and drive design understanding from an architectural point of view. The results are based on annual simulation data, are spatially discrete, and can be d...
Article
Full-text available
When communicating the results of environmental building performance analysis, It Is Important to display resultant information in order (1) to be holistically understood and (2) to guide architectural design decisions. This article proposes a spatial dashboard of environmental performance data as a means to intuitively relate architectural form an...
Conference Paper
Full-text available
Trees play a significant role in influencing daylight availability inside and outside buildings. They temper, scatter and transmit light subsequently reducing the availability or acting as a passive source of daylight. Current daylighting simulation practices either avoid modelling trees or model them as cones, spheres or cylinders with an assumed...
Conference Paper
Full-text available
This paper describes the cataloguing of opaque visual material properties in a database structure based on various measurement processes from the simple (illuminance and luminance measurements) to the complex (spectrophotometers and goniophotometers). A standard rendering environment was setup in the Radiance simulation engine in order to enable co...
Conference Paper
Full-text available
Measuring the luminous environment enables researchers and practitioners to study perception and visual comfort in existing environments in order to decipher the components that contribute to good or problematic lighting characteristics. High dynamic range photography is commonly used to study visual perception and comfort. This paper presents new...
Conference Paper
Full-text available
This paper investigates accuracy in typical High Dynamic Range (HDR) photography techniques used by researchers measuring high resolution luminance information for visual comfort studies in daylit spaces. Vignetting effects of circular fisheye lenses are investigated for reproducibility between different lenses of the same model and sharing between...
Article
Full-text available
A new visual comfort concept is introduced to describe the long-term visual impression of space occupants. This concept, in contrast to instantaneous assessment of visual comfort, aims to describe an overall rating of visual quality in a space. A paired study consisting of occupant surveys and detailed 6-minute time step visual comfort simulations...
Conference Paper
Full-text available
The authors test 168 luminance-calibrated high dynamic range photographs with associated subjective user data against a set of plausible visual comfort metrics and identify metric thresholds at which discomfort can be consistently identified with minimal false-positives. Correlations were identified with vertical eye illuminance, DGI, DGP 5 ∗ L_tas...
Conference Paper
Full-text available
Disability glare, visual impairment due to extreme brightness or contrast, can be caused by intense reflections from new constructions nearby existing transportation or building infrastructure. A case study analysis is performed of a disability glare hazard at an airport created by the installation of a large array of photovoltaic panels between an...
Article
Full-text available
It is desirable to design buildings with natural daylight and views to the outside, which can maximize passive solar heating, minimize electric lighting use and contribute to feelings of wellbeing and awareness. Unfortunately, the presence of daylight is not always a positive one. Excessive brightness, strong contrast or intense reflections from da...
Conference Paper
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One widely recognized opportunity to reduce global carbon emissions is to make urban neighborhoods more resource efficient. Significant effort has hence gone into developing computer-based design tools to ensure that individual buildings use less energy. While these tools are increasingly used in practice, they currently do not allow design teams t...
Conference Paper
Full-text available
We present a method for predicting visual comfort conditions of occupants in daylit spaces. Using an online survey, 67 occupants of a multi-story open plan studio space evaluated long-term visual comfort at their workstations in a substantially daylit space which is known to have glare problems. Visual comfort simulations of each occupant's specifi...
Article
Full-text available
In this paper we present, demonstrate and validate a method for predicting city-wide electricity gains from photovoltaic panels based on detailed 3D urban massing models combined with Daysim-based hourly irradiation simulations, typical meteorological year climactic data and hourly calculated rooftop temperatures. The resulting data can be combined...
Article
Full-text available
Discomfort glare is an underutilized parameter in contemporary architectural design due to uncertainties about the meaning of existing metrics, how they should be applied and what the benefits of such analysis are. Glare is position and view direction-dependent within a space, rendering it difficult to assess compared to conventional illuminance-ba...
Conference Paper
Full-text available
The increasing market demand for early design analysis has created a need for simulation-based decision making tools to evaluate the cost implications of daylight improvements. This study investigates the implications of a tool-based analysis approach for offices, the most typical commercial building type in the United States (US), with respect to...
Conference Paper
Full-text available
This paper describes a highly optimized design workflow for integrating detailed daylighting analysis using Radiance / DAYSIM with thermal load simulations using EnergyPlus within DIVA, a sustainable analysis plugin for the Rhinoceros 3D Nurbs modeling program. First, the importance of using detailed daylighting models is discussed such that occupa...
Article
Full-text available
Five glare indices are compared under 144 daylit conditions in three spaces in order to understand the capability of glare analysis to support the design of visually comfortable spaces. It is found that Daylight Glare Probability (DGP) yields the most plausible results in the investigated spaces and lighting conditions as it is based on contrast an...

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Projects (2)
Project
Research in the Design for Comfort and Climate Lab on regional daylighting preferences in the tropics to establish tropical daylighting and visual comfort preferences that inform daylighting standards in Singapore; understanding how rules of thumb can be applied in Singapore so that detailed lighting simulations are not required for buildings which meet a certain standard of beneficial lighting criteria, and to eventually propose useful daylighting analysis methods and metrics which reflect lighting preferences.