Comfort Assessment of a Fully/Semi-enclosed Courtyard: Case Study of Bahrain Low Rise Villa Housing Model

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The British University in Dubai (BUiD)
The built form industry specifically the residential sector contributes directly on energy consumption and increase of ecological footprint. Bahrain changing built form typology and configuration from introverted to extroverted built forms increased the need of cooling and humidity control measures, by affecting human comfort within the built form. Therefore, extroverted built form contributed to the deteriorating of the environment's comfort level and effected microclimatic conditions. Traditionally, the courtyard built form did not consume excessive amount of energy due to its sustainable microclimatic condition by offering thermal comfort. A scientific literature review of the courtyard built form and its design parameters that affect the courtyard performance were analyzed. Moreover, Bahrain climatic condition as the context of this study was evaluated to relate to the study. This study is an evaluation of the microclimatic condition of both the traditional fully enclosed courtyard and the semi-enclosed courtyard and its influence on the comfort level for the courtyard itself and further its influence on the living room as a selected occupied space within the case study house. The fully enclosed courtyard was integrated within an extroverted modular house for Bahrain case study. As the introverted courtyard built form is achieved, openings were integrated in forming two different courtyard shapes. The study varying parameters were: the courtyard shape, opening orientation, and active mode. Those parameters are assessed on thermal comfort, natural daylight penetration, solar exposure, and airflow through simple CFD representation. ii Ecotect Analysis computer simulation software was used to simulate the two different courtyard configurations, Courtyard-T that represents the fully enclosed courtyard and Courtyard-S that represents the semi-enclosed courtyard. Courtyard-S presents two shapes Courtyard-S-U and Courtyard-S-C. Three orientations and not all as the West and East performance are similar were studied for each configuration and shape: North, South, and West. The simulations were carried out in 21st of June and 21st of December representing extreme seasons summer and winter. The assessments of the results revealed that the fully enclosed courtyard "Courtyard-T" mitigates and modifies the courtyard and living room microclimatic conditions. It recorded to have the lowest exposure to solar radiation, lowest solar heat gain, and highest temperature differential within the living room, also highest air temperature differential within the courtyard, and adequate illuminance level and distribution within the living room. The major value of Courtyard-T configuration is that it has an opening percentage of 30% in relation to the built form. The living room space extends to 5.2208m in order to maintain the total area. The Northern and Eastern courtyard wall has an additional door and two window openings. Courtyard-S-U demonstrated poor performance in all assessments. Courtyard-S-C resulted in modifying the courtyard and living room microclimatic condition, specifically Courtyard-S-C-W, however, it performance was not efficiently as Courtyard-T. The major value of Courtyard-S-C-W configuration is that it has a opening of 2.25m2 oriented on the West. The Southern side of the living room has been deducted to regain the area that was added by the courtyard opening, thus, the courtyard window and door openings shifted 200mm North. Courtyard-S-C-W receives lower solar radiation exposure, lower wind speed within the courtyard, best temperature difference within the courtyard compared to the exterior, and the highest hours of thermal comfort. The courtyard configuration, shape, orientation, geometry, and percentage of enclosure affect its performance. As the opening size increases, simultaneously the wind speed within the courtyard increases. iii It revealed that percentage of enclosure, opening dimensions, courtyard geometry, courtyard shape, and indoor space geometry manipulates the comfort levels within the built form. Sun and wind distribution and exposure in relation to the courtyard shape and opening size demonstrated plausible explanation to their impact on comfort levels. Thus, the study concluded that Courtyard-T configuration promotes an efficient microclimatic condition, and performs best in modifying temperatures, thermal comfort, and light and air distribution. The study suggests some recommendations for further studies in terms of courtyard performance.
comfort assessment, courtyard, Bahrain, low rise villa housing model, energy consumption, thermal comfort, microclimatic condition