Browsing by Author "Elnabawi, M.H"

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    A Behavioural Analysis of Outdoor Thermal Comfort: A Comparative Analysis between Formal and Informal Shading Practices in Urban Sites
    (MDPI AG, 11/01/2020) Elnabawi, M.H; Hamza, N
    This study calls for the integration of context-based socio-cultural habits and learning from local practices in providing outdoor thermal comfort in conservation areas. These parameters have direct impacts on outdoor activities, especially in hot arid climates. The study took place in two nearby locations one renovated and all external shadings removed to provide visual vistas to monuments while on the same street, no more than 1500 m apart, local shading practices were left in places. Sun-exposed as opposed to shaded sites were compared for subjective thermal comfort and outdoor activity, via structured interviews, observations, and wide-ranging micrometeorological measurements. The aim was to investigate psychological factors, including overall thermal comfort and perception, in addition to environmental parameters, such as solar radiation intensity and thermal adaptation. The analysis illustrates the importance of shading as a dominant factor in achieving thermal comfort on the urban scale, with a neutral temperature in summer of 29.9◦C and 29.2◦C for shaded and sun-exposed locations, respectively. The results suggest people may be more willing to tolerate higher temperatures in shaded rather than sun-exposed locations. Moreover, cultural constraints and context-based behaviour proved to have some influences on people’s levels of adaptation and their thermal behaviour. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
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    Outdoor thermal comfort: Coupling microclimatic parameters with subjective thermal assessment to design urban performative spaces
    (MDPI AG, 2020-12) Elnabawi, M.H; Hamza, N
    Thermal comfort plays a main role in encouraging people to use outdoor spaces, specifically in hot arid and humid climates. The reconciliation of climatic aspects during the urban design phase is limited in implementation, due to the need for multidisciplinary collaboration between desperate scientific fields of climatology, urban planning, and urban environmental modelling. This paper aims to create an integrated interface between the microclimate, outdoor thermal comfort, and design guidelines. The investigation combines subjective and objective approaches, including on-site field measurements, a structured questionnaire using the seven-point American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE 55) thermal sensation votes, and a correlation study of these votes and the microclimatic parameters. Pedestrian thermal comfort was then examined under six shading scenarios, addressing the form and opening of shading devices using computational fluid dynamics. Modelling is based on four dependent variables: wind velocity, ventilation flow rate, air temperature, and the physiological equivalent temperature (PET) index. Findings indicate that the form and location of apertures of the shading devices were the dominant factors in achieving thermal comfort on the urban scale, and led to a reduction in air temperature and a physiological equivalent temperature of 2.3–2.4◦C. Subjective votes indicate that people who live in hot arid climates have a wider range of adaptation and tolerance to local climatic conditions Accordingly, a psychometric chart, for the case study outdoor thermal comfort was developed. © 2020 by the authors. Licensee MDPI, Basel, Switzerland