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Based on the findings from a recent study by the authors which examined factors affecting diffusion of photovoltaics (PV), while comprehensively considering the local PV and construction industry as well as characteristics of the built environment, this paper proposes a holistic strategy for PV implementation into Singapore’s built environment. It consists of (1) a multilevel mechanism framework, encompassing eleven mechanism categories of instruments and activities and (2) a general design framework including design principles, general project instructions and the main design guidelines. Relying on a survey conducted among PV experts on established mechanisms, the present study suggests that building codes (e.g., fire safety, structural safety, etc.) and initiatives and incentives related to PV/building-integrated photovoltaics (BIPV) should be the highest priority for authorities, followed by assessment of BIPV/PV properties, working toward social acceptance, conducting research projects and information exchange, and education and training activities. Considering all three pillars of sustainability, the design framework is based on the following interrelated design principles: (1) compatibility and coherence with the local context, (2) technical soundness, (3) economic viability, (4) user-centered design, (5) connecting with community and socio-cultural context, and (6) adaptability and flexibility. Despite Singapore’s scarcity of land, the established design guidelines cover a wide spectrum of solutions, including PV integration into both buildings and non-building structures. The synthesis of the two interconnected and inseparable frameworks aims to create an environment conducive to long-term widespread PV integration and stimulate the deployment of BIPV, which should help Singapore and other cities reduce their dependency on imported fossil fuels, while also making them more livable and enjoyable.
Vesna Kosorić; Siu-Kit Lau; Abel Tablada; Monika Bieri; André M. Nobre. A Holistic Strategy for Successful Photovoltaic (PV) Implementation into Singapore’s Built Environment. Sustainability 2021, 13, 6452 .
AMA StyleVesna Kosorić, Siu-Kit Lau, Abel Tablada, Monika Bieri, André M. Nobre. A Holistic Strategy for Successful Photovoltaic (PV) Implementation into Singapore’s Built Environment. Sustainability. 2021; 13 (11):6452.
Chicago/Turabian StyleVesna Kosorić; Siu-Kit Lau; Abel Tablada; Monika Bieri; André M. Nobre. 2021. "A Holistic Strategy for Successful Photovoltaic (PV) Implementation into Singapore’s Built Environment." Sustainability 13, no. 11: 6452.
Buildings could play a critical role in energy and food production while making high-density cities more resilient. Productive façades (PFs), as flexible and multi-functional systems integrating photovoltaic (PV) and vertical farming (VF) systems, could contribute to transforming buildings and communities from consumers to producers. This study analyses the architectural quality of the developed PF concept drawing on the findings of a web-survey conducted among experts – building professionals in Singapore. The developed design variants are compared with regards to key design aspects such as façade aesthetics, view from the inside, materialisation, ease of operation, functionality and overall architectural quality. The study also compares and discusses the results of the web-survey with the results of a previously conducted door-to-door survey among the potential users – residents of the Housing & Development Board (HDB) blocks. The findings confirm an overall acceptance of the PF concept and reveal a need for synergetic collaboration between architects/designers and other building professionals. Based on the defined PF design framework and the results of the two surveys, a series of recommendations and improved PF prototypes are proposed for further assessment and implementation in order to foster their scalability from buildings into communities and cities.
Abel Tablada; Vesna Kosorić; Huajing Huang; Stephen S.Y. Lau; Veronika Shabunko. Architectural quality of the productive façades integrating photovoltaic and vertical farming systems: Survey among experts in Singapore. Frontiers of Architectural Research 2020, 9, 301 -318.
AMA StyleAbel Tablada, Vesna Kosorić, Huajing Huang, Stephen S.Y. Lau, Veronika Shabunko. Architectural quality of the productive façades integrating photovoltaic and vertical farming systems: Survey among experts in Singapore. Frontiers of Architectural Research. 2020; 9 (2):301-318.
Chicago/Turabian StyleAbel Tablada; Vesna Kosorić; Huajing Huang; Stephen S.Y. Lau; Veronika Shabunko. 2020. "Architectural quality of the productive façades integrating photovoltaic and vertical farming systems: Survey among experts in Singapore." Frontiers of Architectural Research 9, no. 2: 301-318.
Road patterns are highly related to urban ventilation, which plays an important role for improving thermal comfort at the tropics. However, the effects of road intersection angles on the pedestrian-level wind environment remain uncertain. This study investigates the effects of angular road patterns in high-density urban areas using experimental and numerical methods. The studied road patterns are developed from four types of four-way road intersections with various road intersection angles from 90° to 45°. A reduced-scale angular road pattern was first tested in a wind tunnel experiment for validation purposes. The experiment indicates that the Reynolds-averaged Navier-Stokes (RANS) method (κ-ε model) is appropriate to solve the flow in the angular road network. The conducted numerical parametric study suggests the flow field is affected by both the prevailing wind direction and the relative orientation of adjacent road segments (i.e. stream-wise versus lateral; and upstream versus downstream). Based on the results, recommendations are provided for orienting the segments in regular and irregular road networks. In general, upstream road segments should be closely oriented to the wind direction to maximize the overall incoming flow, while moderate inflow angles should be designed for downstream road segments to balance the downstream and lateral flow penetration. These design recommendations of road networks provide the possibility to improve the pedestrian-level wind comfort by optimizing the flow distribution without sacrificing the limited land resources in tropical compact districts.
Yueyang He; Abel Tablada; Nyuk Hien Wong. A parametric study of angular road patterns on pedestrian ventilation in high-density urban areas. Building and Environment 2019, 151, 251 -267.
AMA StyleYueyang He, Abel Tablada, Nyuk Hien Wong. A parametric study of angular road patterns on pedestrian ventilation in high-density urban areas. Building and Environment. 2019; 151 ():251-267.
Chicago/Turabian StyleYueyang He; Abel Tablada; Nyuk Hien Wong. 2019. "A parametric study of angular road patterns on pedestrian ventilation in high-density urban areas." Building and Environment 151, no. : 251-267.
Singapore’s high dependence on imported energy and food resources, and the lack of available land requires an efficient use of the built environment in order to increase energy and food autonomy. This paper proposes the concept of a productive façade (PF) system that integrates photovoltaic (PV) modules as shading devices as well as farming planters. It also outlines the design optimization process for eight PF prototypes comprising two categories of PF systems: Window façade and balcony façade, for four orientations. Five criteria functions describing the potential energy and food production as well as indoor visual and thermal performance were assessed by a parametric modelling tool. Optimal PF prototypes were subsequently obtained through the VIKOR optimization method, which selects the optimal design variants by compromising between the five criteria functions. East and West-facing façades require greater solar protection, and most façades require high-tilt angles on their shading PV panels. The optimal arrangement for vegetable planters involves two planters located relatively low with regard to the railing or window sill. Finally, the optimal façade designs were adjusted according to the availability of resources and the conditions and context of the Tropical Technologies Laboratory (T2 Lab) in Singapore where they are installed.
Abel Tablada; Vesna Kosorić; Huajing Huang; Ian Kevin Chaplin; Siu-Kit Lau; Chao Yuan; Stephen Siu-Yu Lau. Design Optimization of Productive Façades: Integrating Photovoltaic and Farming Systems at the Tropical Technologies Laboratory. Sustainability 2018, 10, 3762 .
AMA StyleAbel Tablada, Vesna Kosorić, Huajing Huang, Ian Kevin Chaplin, Siu-Kit Lau, Chao Yuan, Stephen Siu-Yu Lau. Design Optimization of Productive Façades: Integrating Photovoltaic and Farming Systems at the Tropical Technologies Laboratory. Sustainability. 2018; 10 (10):3762.
Chicago/Turabian StyleAbel Tablada; Vesna Kosorić; Huajing Huang; Ian Kevin Chaplin; Siu-Kit Lau; Chao Yuan; Stephen Siu-Yu Lau. 2018. "Design Optimization of Productive Façades: Integrating Photovoltaic and Farming Systems at the Tropical Technologies Laboratory." Sustainability 10, no. 10: 3762.
The combined effect of climate change and Urban Heat Island (UHI) effect is leading to a rise in air temperature in urban areas, including those with heritage value. Urban morphology and its effect on sun shading conditions in tropical cities is crucial to reduce UHI and improve outdoor thermal comfort. This paper presents a temporal-spatial analysis of the effect of courtyards geometry on their outdoor thermal conditions in a warm-humid climate. The assessment is based on numerical simulations of the mean radiant temperature, by using the RayMan model. Large courtyards geometry (convent typology), in the historical centre of Camagüey, were modelled and analyzed changing their height-to-width ratio and orientation. Our findings confirm the effect of varying courtyard tridimensional aspect ratios on outdoor thermal conditions. Aspect ratios higher than 1 are advisable, as they contribute to improve the courtyard thermal conditions in summer, by reducing the subzones in the courtyard where the Tmrt is above 45 °C. Orienting the courtyard’s long axis away from the East-West results in a lower level of Tmrt, with reductions of up to 15.7 ºC, for high aspect ratios. The obtained Tmrt patterns give information about the most suitable subzones within the courtyards, according to the time of day and season. The proposed design and usability recommendations could be included in renovation projects aimed at enhancing courtyards’ thermal conditions and contributing to an improvement of the surrounding urban microclimate.
José Rodríguez-Algeciras; Abel Tablada; Mabel Chaos-Yeras; Guillermo De la Paz; Andreas Matzarakis. Influence of aspect ratio and orientation on large courtyard thermal conditions in the historical centre of Camagüey-Cuba. Renewable Energy 2018, 125, 840 -856.
AMA StyleJosé Rodríguez-Algeciras, Abel Tablada, Mabel Chaos-Yeras, Guillermo De la Paz, Andreas Matzarakis. Influence of aspect ratio and orientation on large courtyard thermal conditions in the historical centre of Camagüey-Cuba. Renewable Energy. 2018; 125 ():840-856.
Chicago/Turabian StyleJosé Rodríguez-Algeciras; Abel Tablada; Mabel Chaos-Yeras; Guillermo De la Paz; Andreas Matzarakis. 2018. "Influence of aspect ratio and orientation on large courtyard thermal conditions in the historical centre of Camagüey-Cuba." Renewable Energy 125, no. : 840-856.
To improve the photovoltaic (PV) power generation, the temperature control measures and optimization of BIPV systems are critical, particularly in tropical weather. There are two categories of cooling mechanisms, i.e. passive and active cooling. In the present study, a simplified numerical model is set up to evaluate the effect of passive cooling of BIPV façades with various configurations, including the PV periphery openings (i.e. area ratio), behind air cavity depth, wind velocity and attack angle (0 to 90 degrees) on the cell temperature of BIPV module. A parametric study is performed. Three-dimensional computational fluid dynamics (CFD) simulation is applied to predict the cell temperatures under various BIPV façade configurations and environmental conditions. The results of the CFD model show that in the case where the areas of the top and bottom openings are equal, there is limited air ventilation at the behind air cavity. However, the BIPV surface temperature has a significant drop when the inlet opening at the bottom is enlarged, compared with that of the same area of inlet and outlet. Changing the wind attack angle from 0º to 60º has limited effect on the BIPV cell temperature, which results in a variation of less than 5 ºC. However, a dramatic temperature drop of around 15ºC is observed when the attack angle is larger than 60º. The influence of air cavity depth is studied with the fixed top and bottom opening size ratio. By varying the air cavity depth from 30 to 200 mm, a lower PV cell temperature can be achieved.
Siu-Kit Lau; Yong Zhao; Veronika Shabunko; Yuan Chao; Stephen Siu-Yu Lau; Abel Tablada; Thomas Reindl. Optimization and Evaluation of Naturally Ventilated BIPV Façade Design. Energy Procedia 2018, 150, 87 -93.
AMA StyleSiu-Kit Lau, Yong Zhao, Veronika Shabunko, Yuan Chao, Stephen Siu-Yu Lau, Abel Tablada, Thomas Reindl. Optimization and Evaluation of Naturally Ventilated BIPV Façade Design. Energy Procedia. 2018; 150 ():87-93.
Chicago/Turabian StyleSiu-Kit Lau; Yong Zhao; Veronika Shabunko; Yuan Chao; Stephen Siu-Yu Lau; Abel Tablada; Thomas Reindl. 2018. "Optimization and Evaluation of Naturally Ventilated BIPV Façade Design." Energy Procedia 150, no. : 87-93.
Yueyang He; Abel Tablada; Nyuk Hien Wong. Effects of non-uniform and orthogonal breezeway networks on pedestrian ventilation in Singapore's high-density urban environments. Urban Climate 2018, 24, 460 -484.
AMA StyleYueyang He, Abel Tablada, Nyuk Hien Wong. Effects of non-uniform and orthogonal breezeway networks on pedestrian ventilation in Singapore's high-density urban environments. Urban Climate. 2018; 24 ():460-484.
Chicago/Turabian StyleYueyang He; Abel Tablada; Nyuk Hien Wong. 2018. "Effects of non-uniform and orthogonal breezeway networks on pedestrian ventilation in Singapore's high-density urban environments." Urban Climate 24, no. : 460-484.
Despite having the average annual solar irradiation of 1580 kWh/m2, Singapore's current high dependency on fossil fuels (95%) cannot be sufficiently reduced through rooftop PV integrations alone, and façade integrations may present a viable solution for obtaining a higher share of renewable energy generation. The existing Housing and Development Board (HDB) buildings have great potential for both roof and façade PV integration. Since PV building integration is a complex and dynamic process requiring holistic approach and problem-solving strategies in all process stages, its major challenges are finding the proper balance between interrelated and mutually conflicting criteria related to electricity generation performance, economic, environmental, spatial/urban, functional, aesthetic and social aspects. This article defines a general model of PV integration into existing public high-rise residential buildings in Singapore, and also presents challenges and benefits pertaining to it. In order to provide a better understanding of the whole process, the model is divided into seven basic phases detailing the role of each phase and allowing model optimisation at the level of a particular phase. A systematic analysis of each phase is provided, and the problem-solving methods and/or procedures applied are discussed. Vikor method, a multi-criteria decision making (MCDM) method is recommended for a comprehensive evaluation of design variants, selection of the optimal PV integration design variant, and sensitivity analysis testing robustness of the selected design variant “optimality”. The defined methodological framework is also employed to solve PV integration into an existing 12-story slab-block HDB building. The evaluation of created design variants against aesthetic criteria was supported by a customized web survey and qualitative interviews that were performed in order to provide information on opinions and perceptions of local professionals regarding different roof and façade PV integration designs. The analysis of the web survey results is presented and discussed.
Vesna Kosorić; Siu-Kit Lau; Abel Tablada; Stephen Siu-Yu Lau. General model of Photovoltaic (PV) integration into existing public high-rise residential buildings in Singapore – Challenges and benefits. Renewable and Sustainable Energy Reviews 2018, 91, 70 -89.
AMA StyleVesna Kosorić, Siu-Kit Lau, Abel Tablada, Stephen Siu-Yu Lau. General model of Photovoltaic (PV) integration into existing public high-rise residential buildings in Singapore – Challenges and benefits. Renewable and Sustainable Energy Reviews. 2018; 91 ():70-89.
Chicago/Turabian StyleVesna Kosorić; Siu-Kit Lau; Abel Tablada; Stephen Siu-Yu Lau. 2018. "General model of Photovoltaic (PV) integration into existing public high-rise residential buildings in Singapore – Challenges and benefits." Renewable and Sustainable Energy Reviews 91, no. : 70-89.
Effective urban ventilation cools physical surfaces, reduces energy consumption and improves human thermal comfort under hot conditions, especially in tropical and subtropical regions. It is important for planners and architects to understand the influences of urban morphological features on wind environment and air movement. In addition to a concise literature review regarding wind behaviour in tropical and subtropical high-density urban environments, this study uses Computational Fluid Dynamics (CFD) simulations to assess strategies of adjusting breezeway features based on Singapore’s climate. These strategies include: (1) reducing breezeway network densities; (2) varying breezeway widths; (3) varying breezeway spacing; (4) staggering the block; and (5) inserting T-shaped junctions by merging two plots. They were studied in two plot types, namely, separate blocks on top of the podium (type A) or ground (type B), which have the same building plot ratios and site areas. By comparing strategies, in general, the second strategy—varying breezeway widths—achieves the best compromise between pedestrian and building ventilation potentials. On the contrary, the third and fourth strategies lead to poor ventilation. In addition, by comparing the plot types, type B (without podium) tends to achieve better wind environments in most of the strategies. Furthermore, with higher design flexibility, breezeway patterns inside land lots have stronger effects on urban ventilation than breezeway patterns outside land lots. The results in terms of the influence of breezeway network patterns as a design parameter are significant for both planners and architects. For planners, they provide direct guidance for arranging streets and other city open spaces, which should be planned prior to building design. For architects, they offer an effective way to parameterise the building layouts especially those of extreme complexity. Whilst the study focuses on the macro level, both aspects of urban planning and design are important complements to other urban cooling strategies.
Abel Tablada; Yueyang He. Modeling City Patterns for Urban Ventilation: Strategies in High Density Areas of Singapore. Designing Cooler Cities 2017, 119 -135.
AMA StyleAbel Tablada, Yueyang He. Modeling City Patterns for Urban Ventilation: Strategies in High Density Areas of Singapore. Designing Cooler Cities. 2017; ():119-135.
Chicago/Turabian StyleAbel Tablada; Yueyang He. 2017. "Modeling City Patterns for Urban Ventilation: Strategies in High Density Areas of Singapore." Designing Cooler Cities , no. : 119-135.
Yuezhong Liu; Rudi Stouffs; Abel Tablada; Nyuk Hien Wong; Ji Zhang. Comparing micro-scale weather data to building energy consumption in Singapore. Energy and Buildings 2017, 152, 776 -791.
AMA StyleYuezhong Liu, Rudi Stouffs, Abel Tablada, Nyuk Hien Wong, Ji Zhang. Comparing micro-scale weather data to building energy consumption in Singapore. Energy and Buildings. 2017; 152 ():776-791.
Chicago/Turabian StyleYuezhong Liu; Rudi Stouffs; Abel Tablada; Nyuk Hien Wong; Ji Zhang. 2017. "Comparing micro-scale weather data to building energy consumption in Singapore." Energy and Buildings 152, no. : 776-791.
Walkability and livability in cities can be enhanced by creating comfortable environments in the streets. The profile of an urban street canyon has a substantial impact on outdoor thermal conditions at pedestrian level. This paper deals with the effect of asymmetrical street canyon profiles, common in the historical centre of Camagüey, Cuba, on outdoor thermal comfort. Temporal-spatial analyses are conducted using the Heliodon2 and the RayMan model, which enable the generation of accurate predictions about solar radiation and thermal conditions of urban spaces, respectively. On these models, urban settings are represented by asymmetrical street canyons with five different height-to-width ratios and four street axis orientations (N-S, NE-SW, E-W, SE-NW). Results are evaluated for daytime hours across the street canyon, by means of the physiologically equivalent temperature (PET index) which allows the evaluation of the bioclimatic conditions of outdoor environments. Our findings revealed that high profiles (façades) located on the east-facing side of N-S streets, on the southeast-facing side of NE-SW streets, on the south-facing side of E-W street, and on the southwest-facing side of SE-NW streets, are recommended to reduce the total number of hours under thermal stress. E-W street canyons are the most thermally stressed ones, with extreme PET values around 36 °C. Deviating from this orientation ameliorates the heat stress with reductions of up to 4 h in summer. For all analysed E-W orientations, only about one fifth of the street can be comfortable, especially for high aspect ratios (H/W > 3). Optimal subzones in the street are next to the north side of the E-W street, northwest side of the NE-SW street, and southwest side of the SE-NW street. Besides, when the highest profile is located on the east side of N-S streets, then the subzone next to the east-facing façade is recommendable for pedestrians. The proposed urban guidelines enable urban planners to create and renovate urban spaces which are more efficient in diminishing pedestrian thermal stress.
José Rodríguez-Algeciras; Abel Tablada; Andreas Matzarakis. Effect of asymmetrical street canyons on pedestrian thermal comfort in warm-humid climate of Cuba. Theoretical and Applied Climatology 2017, 133, 663 -679.
AMA StyleJosé Rodríguez-Algeciras, Abel Tablada, Andreas Matzarakis. Effect of asymmetrical street canyons on pedestrian thermal comfort in warm-humid climate of Cuba. Theoretical and Applied Climatology. 2017; 133 (3-4):663-679.
Chicago/Turabian StyleJosé Rodríguez-Algeciras; Abel Tablada; Andreas Matzarakis. 2017. "Effect of asymmetrical street canyons on pedestrian thermal comfort in warm-humid climate of Cuba." Theoretical and Applied Climatology 133, no. 3-4: 663-679.
Abel Tablada; Ian Chaplin; Huajing Huang; Vesna Kosoric; Siu Kit Lau; Chao Yuan; Stephen Lau. Assessment of Solar and Farming Systems Integration on Tropical Building Facades. Proceedings of SWC2017/SHC2017 2017, 1 .
AMA StyleAbel Tablada, Ian Chaplin, Huajing Huang, Vesna Kosoric, Siu Kit Lau, Chao Yuan, Stephen Lau. Assessment of Solar and Farming Systems Integration on Tropical Building Facades. Proceedings of SWC2017/SHC2017. 2017; ():1.
Chicago/Turabian StyleAbel Tablada; Ian Chaplin; Huajing Huang; Vesna Kosoric; Siu Kit Lau; Chao Yuan; Stephen Lau. 2017. "Assessment of Solar and Farming Systems Integration on Tropical Building Facades." Proceedings of SWC2017/SHC2017 , no. : 1.
A transition to a solar-based carbon neutral economy is crucial to reduce the overall ecological footprint and greenhouse gas (GHG) emissions while providing new housing for the growing urban population worldwide. One of the key measures to achieve such reductions as a way to mitigate and adapt to climate change is to increase food and energy self-sufficiency in residential areas. The objective of this study is to explore the potential self-sufficiency in terms of food and energy in generic residential districts in Singapore and Southeast Asia. Computational tools are employed to obtain quantifiable indicators based on sunlight availability. A series of building typologies and urban forms was created as abstractions from actual residential developments in Singapore (1.3°N). In total, 57 cases were assessed in terms of sunlight availability and the impact of three density and geometry parameters: plot ratio, site coverage and building height were considered. Results from selected cases were compared to Hanoi’s conditions (21°N). The results show that the indicators having the higher impact on the food and energy self-sufficiency are plot ratio and building height. The cases with the lowest plot ratio (PR < 1.9) achieved food self-sufficiency when a hybrid higher-yield farming method was applied. Regarding energy harvesting, the cases with the lowest building height (<42 m) achieve energy self-sufficiency due to the maximum exposed area with PV per number of residents. In low-latitude regions, solar access is more evenly distributed among all facade orientations than in higher latitudes, therefore providing all facade orientations with food and energy harvesting potential. Food and energy self-sufficiency in equatorial regions is more heavily influenced by the available farming and PV area in relation to the total population than by the reduction of sunlight availability due to building typology and morphology.
Abel Tablada; Xi Zhao. Sunlight availability and potential food and energy self-sufficiency in tropical generic residential districts. Solar Energy 2016, 139, 757 -769.
AMA StyleAbel Tablada, Xi Zhao. Sunlight availability and potential food and energy self-sufficiency in tropical generic residential districts. Solar Energy. 2016; 139 ():757-769.
Chicago/Turabian StyleAbel Tablada; Xi Zhao. 2016. "Sunlight availability and potential food and energy self-sufficiency in tropical generic residential districts." Solar Energy 139, no. : 757-769.
The Historical Centre of Old Havana in Cuba is currently undergoing a comprehensive preservation and urban recovering program. Housing units are built in existing vacant plots of the old city. The design of the new buildings should be integrated in the compact urban structure that has developed throughout the past centuries. This compact morphology, however, obstructs the breezes that are an essential component to achieve thermal comfort by passive means in warm and humid climates. New courtyard buildings should be designed in such a way that natural ventilation and thermal comfort are enhanced. Research on natural ventilation and thermal comfort in compact urban environments, however, is scarce. This paper first presents an historical overview of the typological evolution of the residential architecture in this part of the city and its relation to natural ventilation and thermal comfort. Next, it provides a partial study of the morphological characteristics of the Historical Centre. From this study, appropriate locations have been selected for field measurements and a limited comfort survey, from which a tentative summer comfort zone for residential buildings in Old Havana is suggested. Finally, based on the historical overview, the measurements and the survey, some preliminary design recommendations for residential buildings in Old Havana are provided.
A. Tablada; F. De Troyer; Bert Blocken; J. Carmeliet; H. Verschure. On natural ventilation and thermal comfort in compact urban environments – the Old Havana case. Building and Environment 2009, 44, 1943 -1958.
AMA StyleA. Tablada, F. De Troyer, Bert Blocken, J. Carmeliet, H. Verschure. On natural ventilation and thermal comfort in compact urban environments – the Old Havana case. Building and Environment. 2009; 44 (9):1943-1958.
Chicago/Turabian StyleA. Tablada; F. De Troyer; Bert Blocken; J. Carmeliet; H. Verschure. 2009. "On natural ventilation and thermal comfort in compact urban environments – the Old Havana case." Building and Environment 44, no. 9: 1943-1958.
Building ventilation potential and pollutant dispersion are greatly affected by the airflow pattern in street canyons. Two reasons for airflow in a street canyon exist: wind washing and buoyancy due solar radiation on one of the facades of the street canyon. The importance of the buoyancy effect inside street canyons can be characterised by the Froude (Fr) number which is directly related to the air speed (Uref) on top of the boundary layer and inversely related to the temperature difference between the heated wall and the ambient air temperature and to the height of the street canyon. The wind effect on the airflow pattern inside courtyards and on thermal comfort in the surrounding rooms has been studied extensively by Tablada (2006) (1). To study both wind and buoyancy effects, experiments were performed by Kovar-Panskus et al. (2002) (2) in a wind tunnel on a square street canyon. One street façade was heated to obtain a uniform temperature over its whole surface. The airflow pattern inside the street canyon was measured for four different Froude numbers: 2.03, 1.17, 0.73 and 0.27. They found a marked transition from a single dominant vortex, existing at higher Fr values (dominant wind effects), to a combination of vortices due to buoyancy and wind effects. Below Fr ≈ 1, the main vortex shifts to the top of the canyon and a lower counter-rotating vortex develops against the heated wall. The objective of this study is to analyse in more detail the relative importance of wind versus thermal stack on the type of airflow pattern. This is done by further analysing the airflow pattern in a square canyon by numerical calculations using Computational Fluids Dynamics (CFD) for the Kovar-Panskus experiment configuration. Using CFD for an array of wind velocities (ranging from 0.1 to 10 m/s) and surface temperature of one street façade (temperature differential with ambient air varying from 5 to 93K), 42 simulations were performed (Froude numbers ranging from Fr = 0.0115 to Fr = 2146). The results show that for high wind velocities (Fr>30), at any temperature differential, one single main vortex is formed, highlighting the predominant role of wind in the airflow pattern in the street canyon. At lower velocities, the airflow patterns depend on temperature. At high temperature differential, a vortex is formed on the full height of the street façade, compressing the wind induced vortex to one side of the canyon. At low temperature differential, the two vortex touch the heated façade, in the upper part is the wind-induced vortex, in the lower part is the thermal stack-induced vortex. Results are presented in function of the Froude number. (1) Tablada A. Shape of new residential buildings in the Historical Centre of Old Havana to favour natural ventilation and thermal comfort. PhD Thesis, Department of Architecture, Urbanism and Planning, Katholieke Universiteit Leuven. 2006. (2) Kovar-Panskus A, Moulinneuf L, Savory E, Abdelqari A, Sini JF, Rosant, JM, Robins A, Toy N. A wind tunnel investigation of the influence of solar-induced wall-heating on the flow regime within a simulated urban street canyon. Water, Air, & Soil Pollution: Focus 2, 2002, pp 555-571. doi: 10.1023/A:1021345131117
Abel Tablada De La Torre; Bert Blocken; Jan Carmeliet. Influence of wind and thermal stack on street canyon airflow pattern. 2021, 1 .
AMA StyleAbel Tablada De La Torre, Bert Blocken, Jan Carmeliet. Influence of wind and thermal stack on street canyon airflow pattern. . 2021; ():1.
Chicago/Turabian StyleAbel Tablada De La Torre; Bert Blocken; Jan Carmeliet. 2021. "Influence of wind and thermal stack on street canyon airflow pattern." , no. : 1.
Re-use and renovation of buildings are core strategies towards a rational environmental policy. It preserves not only the city memory and cultural values but also diminish the use of non-removable natural resources and save energy. However, many after-war modern buildings in Europe have poor climatic design which can leads both to uncomfortable indoor conditions during hot summers and to a high energy consumption by cooling. This study focuses on the simulation, evaluation and improvement of indoor thermal comfort in an existing free-standing residential building in Palermo, Sicily (see ref. 1,2). The evaluation and quantification of the (dis)comfort is a result of simulations carried out by coupling Computational Fluid Dynamics (CFD) and Building Energy Simulation programs (BES). Values of indoor air speed and pressure coefficients are obtained from CFD calculations and further used as input in BES calculations and comfort analysis. Two BES programs EnergyPlus and TRNSYS are compared. Both programs are coupled with airflow simulation program COMIS. Simplified and improved calculation methods are respectively used in CFD and BES programs for the cases of vertical and horizontal louver systems. Special attention has been given to the physical model, boundary conditions and influencing parameters. The results show that the use of CFD calculations is required for the prediction of indoor air speed which is a necessary parameter for comfort calculations. Concerning the comfort analysis, the results show that in this particular case the overheating problem could be improved by passive means by the application of several strategies like the use of existing balconies with external louver systems and whole day natural cross ventilation. (1) Karelien Vaes, Sara Van Praet, Development of sustainable renovation strategies, concentrated on natural ventilation, for residential buildings in Palermo. Master thesis, K.U.Leuven, 2007. (2) Sofie Mols, Hanne Van Beurden, Passive concepts for thermal comfort with focus on fixed solar shading devices. Master thesis, K.U.Leuven, 2007.
Abel Tablada De La Torre; Jan Carmeliet. Passive strategies to improve summer comfort in the renovation of a free-standing residential building: evaluation of horizontal and vertical louver systems. 2021, 1 .
AMA StyleAbel Tablada De La Torre, Jan Carmeliet. Passive strategies to improve summer comfort in the renovation of a free-standing residential building: evaluation of horizontal and vertical louver systems. . 2021; ():1.
Chicago/Turabian StyleAbel Tablada De La Torre; Jan Carmeliet. 2021. "Passive strategies to improve summer comfort in the renovation of a free-standing residential building: evaluation of horizontal and vertical louver systems." , no. : 1.