Dr. Abdelaziz Laouadi

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Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

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30 June 2022 in Buildings

Journal Article

Nature-Based Solutions (NBSs) to Mitigate Urban Heat Island (UHI) Effects in Canadian Cities

Alexander Thomas Hayes

Canada is warming at double the rate of the global average caused in part to a fast-growing population and large land transformations, where urban surfaces contribute significantly to the urban heat island (UHI) phenomenon. The federal government released the strengthened climate plan in 2020, which emphasizes using nature-based solutions (NBSs) to combat the effects of UHI phenomenon. Here, the effects of two NBSs techniques are reviewed and analysed: increasing surface greenery/vegetation (ISG) and increasing surface reflectivity (ISR). Policymakers have the challenge of selecting appropriate NBSs to meet a wide range of objectives within the urban environment and Canadian-specific knowledge of how NBSs can perform at various scales is lacking. As such, this state-of-the-art review intends to provide a snapshot of the current understanding of the benefits and risks associated with the implantation of NBSs in urban spaces as well as a review of the current techniques used to model, and evaluate the potential effectiveness of UHI under evolving climate conditions. Thus, if NBSs are to be adopted to mitigate UHI effects and extreme summertime temperatures in Canadian municipalities, an integrated, comprehensive analysis of their contributions is needed. As such, developing methods to quantify and evaluate NBSs’ performance and tools for the effective implementation of NBSs are required.

30 September 2022 in Buildings

Journal Article

A New General Formulation for the PMV Thermal Comfort Index

Abdelaziz Laouadi

The PMV index forms the basis of international thermal comfort standards. PMV was developed based on empirical relationships between the metabolic rate of activity and the body mean skin temperature and evaporative heat loss under the comfort conditions. However, many recent studies have questioned the accuracy and reliability of the PMV predictions, particularly for the discomfort range. This paper develops a general formulation of PMV that does not involve the mean skin temperature and evaporative heat loss. The new metabolic-based predicted mean vote (MPMV) index is expressed as the difference between the metabolic rate of activity and the metabolic rate required to achieve a comfort state under the imposed environment conditions. The comfort metabolic rate is found to vary linearly with the metabolic rate required to maintain the body core and mean skin temperatures at the resting thermo-neutral state. The model constants are determined using public experimental data on thermal sensation votes of young and older people. The new formulation accounts for body core cooling to achieve comfort under hot exposures; it also addresses the overlooked non-shivering thermogenesis in the body heat balance at the comfort state and covers comfort requirements for young and older people in wakeful and sleep states.

18 February 2020 in Journal of Building Performance Simulation

Journal Article

Development of reference summer weather years for analysis of overheating risk in buildings

Abdelaziz Laouadi

Abhishek Gaur

M. A. Lacasse

M. Bartko

M. Armstrong

Overheating in buildings arising from climatic extreme heat events has been identified as a health concern to vulnerable occupants. However, there have been very limited studies to generate suitable weather data to evaluate by simulation the overheating risk and its effect on the comfort and health of occupants. This paper develops a methodology to identify reference summer weather years (RSWY) for overheating risk analysis. The methodology includes generation of historical climate data, and development of a heat stress metric for the definition and characterization of heat events. The Standard Effective Temperature was selected among a short list of popular metrics, modified and named t-SET to account for transient heat events, activity levels of occupants, and thermoregulatory controls of sleeping subjects. The t-SET model predictions compared well with measured body temperatures of subjects undergoing multi-stage activities under hot conditions. The t-SET index was used to generate RSWY for selected Canadian cities.

19 March 2008 in Journal of Building Performance Simulation

Journal Article

Efficient calculation of daylight coefficients for rooms with dissimilar complex fenestration systems

Abdelaziz Laouadi

C. F. Reinhart

D. Bourgeois

The daylight coefficient (DC) method is a powerful and efficient method to perform annual daylight illuminance simulation. A set of coefficients are calculated for a given room space and static fenestration systems prior to simulation start. Time series of indoor daylight illuminances are obtained by only knowing the sky luminance. However, for rooms with dissimilar dynamic complex fenestration systems (such as windows with movable shadings) whose optical behaviour (transmission, reflection and scattering) may change during simulation, the efficiency of the DC method may be compromised as another whole set of coefficients must be re-calculated. This study presents the development of a new methodology to compute the DC set for rooms with dissimilar complex fenestration components only once prior to simulation start. A validation study is carried out, in which the daylight illuminances in an office space equipped with a clear window and internal Venetian blinds are compared using predictions from the present model, the Radiance program, as a benchmark model employing detailed optical model of Venetian blinds, and the Daysim program employing a simple engineering blinds model. Findings from the validation study show that the present model yields overall accurate results when compared with the benchmark model for any window orientation, although some local illuminance differences are observed in areas under direct sunlight exposure.

7 March 2022 in Building Simulation

Journal Article

Development of a bioheat model for older people under hot and cold exposures

Lili Ji

Abdelaziz Laouadi

Liangzhu Wang

Michael A. Lacasse

1 February 2023 in Buildings

Journal Article

Overheating Risk Analysis in Long-Term Care Homes—Development of Overheating Limit Criteria

Climate heat waves occurring in urban centers are a serious threat to public health and wellbeing. Historically, most heat-related mortalities have arisen from excessive overheating of building interiors housing older occupants. This paper developed an approach that combines the results from building simulation and bioheat models to generate health-based limit criteria for overheating in long-term care homes (LTCHs) by which the body dehydration and core temperature of older residents are capped during overheating events. The models of the LTCHs were created for buildings representative of old and current construction practices for selected Canadian locations. The models were calibrated using measurements of indoor temperature and humidity acquired from monitoring the building interiors and the use of published building energy use intensity data. A general procedure to identify overheating events and quantify their attributes in terms of duration, intensity, and severity was developed and applied to LTCHs to generate the limit criteria. Comparing the limit criteria from the proposed and comfort-based methods showed evident differences. The proposed method predicted the overheating risk consistent with the overall thermal comfort during overheating events in contrast to the comfort-based methods. The new limit criteria are intended to be used in any study to evaluate overheating risk in similar buildings.

About Me

Abdelaziz (Aziz) Laouadi is a Senior Research Officer. His education is as follows: Ph.D. Mech. Eng., University of Sherbrooke, Québec, Canada (1996); M.A.Sc. Mech. Eng., University of Sherbrooke, Québec, Canada (1993); and B.A.Sc. Mech. Eng., University of Saad Dahlab, Algeria (1989). His work experience is a follows: National Research Council, Ottawa, Ontario, Canada (1998–pres.): Senior Research Officer (1996–1998): Post-Doctoral Fellow; University of Sherbrooke, Sherbrooke, Quebec (1991–1996): Research and Teaching Assistant. Laouadi's research interests include building thermal resilience, overheating in buildings, thermal comfort, physiological modelling, thermal performance of building envelopes, building energy and daylighting simulation, and fenestration and daylighting systems. Laouadi has earned the following awards: 2022 Construction Research Centre Excellence in Environmental Stewardship Award; 2021 Construction Research Centre Excellence in Research Award; 2021 NRC Outstanding Achievement Award—NRC value for Canada Award; 2020 NRC Inventor Fixed Milestone Award for 2019-2020; 2019 NRC Construction Research Centre—Value for Canada Award; 2016 NRC Construction Partnership Award; NRC Construction General Manager’s Innovation Award 2005; and the IRC Lorne W. Gold Award—best publication: Development of a radiant heating and cooling model for building energy simulation software. Please check to ensure your intended meaning is retained.

Dr. Abdelaziz Laouadi

Dr. Abdelaziz Laouadi

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