scholarly journals TINJAUAN TERHADAP STRATEGI PENGHAWAAN RUANG PERKOTAAN MELALUI ATAP HIJAU

2018 ◽  
Vol 16 (02) ◽  
pp. 76
Author(s):  
M Donny Kurniawan ◽  
Suhendri .
Keyword(s):  
Fluid Dynamics ◽  
Urban Heat Island ◽  
Cfd Simulation ◽  
Urban Canyon ◽  
Outdoor Thermal Comfort ◽  
Wind Flow ◽  
Heat Island ◽  
Urban Heat ◽  
Computational Fluid Dynamics Cfd ◽  
Roof Garden

<p>Kenyamanan termal di ruang luar menjadi isu yang penting saat ini akibat kenaikan yang signifikan pada suhu udara perkotaan. Kenaikan suhu ini diakibatkan oleh perubahan iklim global dan fenomena pulau panas perkotaan (Urban Heat Island) faktor pulau panas perkotaan ini dapat direduksi salah satunya dengan penghawaan pasif di ruang-ruang perkotaan. Dalam rancangan kota, penghawaan perkotaan dapat berupa pengaturan massa-massa bangunan, orientasi jalan, sampai ke detail desain bagunan yang dirancang untuk mengalirkan angin. Kota dengan penghawaan perkotaan yang baik dapat melepaskan panas yang terperangkap di antara bangunan melalui angin, juga dapat memberikan kenyamanan termal pada ruang luar. Penelitian ini bertujuan untuk mengetahui efektivitas strategi pengahawaan perkotaan dengan perletakan atap hijau di bangunan tinggi. Efektivitas ini ditinjau dari hasil simulasi Computational Fluid Dynamics (CFD) terhadap berbagai posisi perletakan atap hijau pada bangunan tinggi. Hasil simulasi didapat dari dua metode simulasi, yaitu CFD 3 dimensi pada skala kota dan CFD 2 dimensi pada urban canyon. Kedua simulasi tersebut menunjukkan bahwa atap hijau yang diletakkan pada posisi yang tepat di sebuah bangunan tinggi dapat memicu pergerakan angin yang potensial bagi reduksi pulau panas perkotaan sekaligus memberikan kenyamanan termal ruang luar di perkotaan.</p><p> </p><p>Kata kunci: <em>kenyamanan termal ruang luar, pulau panas perkotaan, atap hijau, CFD</em></p><p><em> </em></p><p><strong> </strong></p><p align="center"><strong><em>ABSTRACT</em></strong></p><p><em>Cities are facing temperature increase due to global warming and urban heat island. Although the global warming needs to be solved with global acts, the urban heat island presumably can be reduced by ventilated city strategies. Ventilated cities are designed to create a preferable wind flow in the city’s spaces. Thus, it releases heat that is trapped in the urban canyon and reduces urban heat island. Wind generated by the strategy could also provide outdoor thermal comfort in the cities. One of the ventilated city strategies are by utilizing roof garden for high rise buildings. Therefore, this research is aimed to identify the effectivity of roof garden in delivering wind flow. Two computational fluid dynamics (CFD) simulation schemes had been analyzed, and this paper reviews the results. The schemes are 3D CFD simulation for urban area and 2D CFD simulation for urban canyon. Review of the result analysis shows that roof garden is potential to drive a sufficient wind flow as long as its position is appropriate.</em></p><p><em> </em></p><p><em>Keywords : </em><em>outdoor thermal comfort, urban heat island, roof garden, CFD</em><em></em></p>

scholarly journals Biomimicry-Based Strategies for Urban Heat Island Mitigation: A Numerical Case Study under Tropical Climate

Biomimetics ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 48
Author(s):  
Kevin Araque ◽  
Paola Palacios ◽  
Dafni Mora ◽  
Miguel Chen Austin
Keyword(s):  
Thermal Comfort ◽  
Urban Heat Island ◽  
Urban Areas ◽  
Outdoor Thermal Comfort ◽  
Base Case ◽  
Heat Island ◽  
Urban Heat ◽  
Historical Heritage ◽  
Pet Index ◽  
Radiant Temperature

In recent years, demographic growth has caused cities to expand their urban areas, increasing the risk of overheating, creating insurmountable microclimatic conditions within the urban area, which is why studies have been carried out on the urban heat island effect (UHI) and its mitigation. Therefore, this research aims to evaluate the cooling potential in the application of strategies based on biomimicry for the microclimate in a historical heritage city of Panama. For this, three case studies (base case, case 1, and case 2) of outdoor thermal comfort were evaluated, in which the Envi-met software was used to emulate and evaluate the thermal performance of these strategies during March (highest temperature month) and October (rainier month). The strategies used were extracted from the contrast of zebra skin, human skin, evaporative cooling, and ant skin. The results showed a reduction of 2.8 °C in the air temperature at 11:00, the radiant temperature decreased by 2.2 °C, and the PET index managed to reduce the thermal comfort indicator among its categories. The importance of thinking based on biomimicry in sustainable strategies is concluded; although significant changes were obtained, high risks of discomfort persist due to the layout and proximity of the building.

scholarly journals Pressure Coefficients Acting Upon the Cylinder Obtained by Numerical and Experimental Analysis

2017 ◽  
Vol 13 (2) ◽  
pp. 149-155
Author(s):  
Soňa Medvecká ◽  
Oľga Ivánková ◽  
Marek Macák
Keyword(s):  
Fluid Dynamics ◽  
Boundary Layer ◽  
Cross Section ◽  
Cfd Simulation ◽  
Circular Cross Section ◽  
Wind Pressure ◽  
Wind Flow ◽  
Pressure Coefficients ◽  
High Rise ◽  
Computational Fluid Dynamics Cfd

Abstract Analysis of wind flow acting upon high-rise buildings is a very common topic. This paper deals with experiment in the Boundary Layer Wind Tunnel (BWLT) in Bratislava and comparison with the computational fluid dynamics (CFD) simulation and values given in the Eurocode. The analyzed object was the model of building with circular cross section (cylinder). External wind pressure coefficients were compared in three height levels of model.

scholarly journals Cooling Strategies for Thermal Comfort in Cities: A Review of Key Methods in Landscape Design

2021 ◽  
Author(s):  
Mo Zou ◽  
Heng Zhang
Keyword(s):  
Urban Planning ◽  
Thermal Comfort ◽  
Urban Heat Island ◽  
Landscape Design ◽  
Urban Morphology ◽  
Outdoor Thermal Comfort ◽  
Theoretical Research ◽  
Heat Island ◽  
Design Elements ◽  
Urban Heat

Abstract Under the climate change scenario, the negative impacts of urban heat island (UHI) will exacerbate due to unsustainable urban planning and human activities. Thermal comfort has close relationships with UHI in urban areas. This paper is based on the studies of urban heat island, thermal comfort, microclimate and urban planning in cities in the recent decade, combined with cross-analysis research method. The key topics include vegetation and water conditions, the albedo of materials, urban morphology and more. By the comparative case studies in landscape projects, the results further reveal that the density of tree canopies, the natural structure and density of ground cover, the form of water features, the colour and texture of materials, and the scale of shading structures have different cooling effect and performance in outdoor thermal comfort improvement with specific features in the landscape design. It is also found that there are some external conditions that can influence design determinations in real practices. The purpose of this study is to provide theoretical research methods and evaluation of thermal comfort landscape design elements, and to provide guidance for future sustainable city research and landscape design.

scholarly journals Numerical investigation of the effect of triangle strut in vertical axis wind turbine (VAWT)

2020 ◽  
Vol 11 (2) ◽  
pp. 95
Author(s):  
Tri Admono ◽  
Yoyon Ahmudiarto ◽  
Amma Muliya Romadoni ◽  
Iman Abdurahman ◽  
Agus Salim ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Wind Turbine ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
Simulation Method ◽  
Wind Flow ◽  
Vertical Axis Wind Turbine ◽  
Pressure Losses ◽  
Multi Stage ◽  
Computational Fluid Dynamics Cfd

Strut is used in vertical axis wind turbine (VAWT) to restraint the framework. In this study, struts are analyzed to show the pressure losses in VAWT. ANSYS computational fluid dynamics (CFD) software is used to investigate triangle strut in VAWT. This study aims to show a CFD simulation of struts, which affects the aerodynamic of VAWT. In CFD software, the aerodynamic of VAWT can be analyzed in terms of pressure losses in the struts. The simulation method starts by making a struts model, then meshing and setting up ANSYS's boundary conditions. The last iteration runs in ANSYS until convergence. Our results show the percentage of pressure losses with the variation of the angle of wind 0°, 20°, 40°, and 60° are 0.67 %, 0.52 %, 0.48 %, and 0.52 %. The effect of triangle strut in VAWT did not affect the wind flow to the VAWT blade. The results also indicated that the triangle strut could be applied in the multi-stage of VAWT system.

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