scholarly journals THE WIND AND THE CITY: EVALUATING THE LIMITS TO APPLY NATURAL VENTILATION FOR THERMAL COMFORT IN DENSE URBAN SETTLEMENTS USING A COMPUTATIONAL FLUID DYNAMICS TOOL.

Author(s):  
R. C. V. Leite ◽  
A. B. Frota
2019 ◽  
Vol 41 (4) ◽  
pp. 466-479
Author(s):  
S Subhashini ◽  
K Thirumaran

This paper attempts to investigate the potential of courtyards in optimizing natural ventilation and improving comfort levels in the learning spaces of a naturally ventilated educational institution with courtyards in the warm-humid climatic region of Madurai. Field measurements and experimental studies were carried out to predict the indoor and outdoor environmental conditions. The numerical study was carried out using computational fluid dynamics-based simulations using Ansys Fluent as the solver. The main aim of the simulation is to understand the airflow pattern and air velocity fields inside the classrooms surrounding the courtyards for different wind directions. The computational fluid dynamics results were validated by comparing it with the experimental results obtained in the current study and numerical results from other studies. The major findings of the current study suggest that courtyards with an aspect ratio of 1:2, orientations of openings at an angle of 0–20° to the predominant wind directions and the overall percentage of openings between 15 and 30% in buildings in Madurai region can enhance natural ventilation and thus improve thermal comfort of the occupants. Practical application: Naturally ventilated buildings in warm-humid climates have difficulty in providing thermal comfort to the occupants. CFD tools have been used to predict the ventilation performance of a naturally ventilated educational building with courtyards. The CFD results were helpful in identifying the implication of building design on the indoor air flow pattern. The recommendations given in this paper are applicable to any building type which relies on natural ventilation for thermal comfort provided they have similar building configurations, boundary conditions and weather conditions. The study is intended to help architects and building designers in the effective design of naturally ventilated buildings with respect to its climatic conditions.


2014 ◽  
Vol 493 ◽  
pp. 74-79
Author(s):  
Y.A. Sabtalistia ◽  
S.N.N. Ekasiwi ◽  
B. Iskandriawan

Energy consumption for air conditioning systems (air conditioning system) increased along with the increasing need for fresh air and comfortable in the room especially apartments. FAC system (Floor Air Conditioning) is growing because it is more energy efficient than CAC (Ceiling Air Conditioning) system. However, the position of the AC supply is on the lower level at the FAC system causes draft discomfort becomes greater as air supply closer to the occupants so that thermal comfort can be reduced. Heat mixture of windows, exterior walls, kitchen, and occupants in the studio apartment affect thermal comfort in the room too.This study aims to determine the position of the AC supply which has the best thermal comfort of FAC system in the studio apartment. It can be done by analyzing ADPI (Air Diffusion Performance Index), the distribution of air temperature, wind speed, RH (Relative Humidity), and DR (Draft Risk) to change the position of the AC supply supported by CFD (Computational Fluid Dynamics) simulation.This result prove that AC position 2 (on wall near the kitchen) is more comfortable than AC position 1 (on the bathroom wall) because AC position 2 away from occupied areas, thereby reducing the occurrence of draught discomfort.


Author(s):  
Peter Abdo ◽  
Rahil Taghipour ◽  
B. P. Huynh

Abstract Windcatcher has been used over centuries for providing natural ventilation using wind power, it is an effective passive method to provide healthy and comfortable indoor environment. The windcatcher’s function is based on the wind and on the stack effect resulting from temperature differences. Generally, it is difficult for wind to change its direction, and enter a room through usual openings, the windcatcher is designed to overcome such problems since they have vertical columns to help channel wind down to the inside of a building. The efficiency of a windcatcher is maximized by applying special forms of opening and exit. The openings depend on the windcatcher’s location and on its cross sectional area and shape such as square, rectangular, hexagonal or circular. In this study the effect of the inlet design is investigated to achieve better air flow and increase the efficiency of windcatchers. To achieve this, CFD (computational fluid dynamics) tool is used to simulate the air flow in a three dimensional room fitted with a windcatcher based on the different inlet designs. The divergent inlet has captured the highest air flow with a difference of approximately 3% compared to the uniform inlet and 5% difference compared to the bulging-convergent inlet.


2019 ◽  
Vol 111 ◽  
pp. 01040
Author(s):  
Ahmed A. Masoud ◽  
Essam E. Khalil ◽  
Abdelmaged H. Ibrahim ◽  
Esmail M. ElBialy

This work investigates the feasibility and thermal comfort of using natural ventilation in order to achieve thermal comfort in a handball arena with realistic dimensions and a full occupation of 4300 persons in the Gulf area. The work numerically simulates the temperature and velocity fields inside the full arena using computational fluid dynamics techniques at different internal loads, prevailing wind speeds, prevailing wind temperatures and prevailing wind angles. The work generates certain air opening configuration to be used for natural ventilation and the results show that natural ventilation is feasible if the following conditions are met simultaneously: the occupation density is 25% or less, sitting in the prevailing wind side, the lighting load does not exceed 50% of its full capacity, the prevailing wind temperature does not exceed 30 °C and the prevailing wind velocity is in range 3-4 m/s, where the upper limit arises from the requirement to avoid high velocities in the playing area. These conditions can be met during the training time and during parts of the day and over parts of the year hours making this method conditionally feasible.


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