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DESIGN FOR COMFORT: DESIGN BUILDING ENVELOPE TO IMPROVE THERMAL COMFORT FOR RESIDENTIAL BUILDINGS IN AL-MUKALA, YEMEN
Title
DESIGN FOR COMFORT: DESIGN BUILDING ENVELOPE TO IMPROVE THERMAL COMFORT FOR RESIDENTIAL BUILDINGS IN AL-MUKALA, YEMEN
Creator
Bakarmom, Aamena Mubarak Saeed
Date
2021
Description
This thesis is about the research into the design of building envelopes to reduce energy consumption and moderate thermal performance of the...
Show moreThis thesis is about the research into the design of building envelopes to reduce energy consumption and moderate thermal performance of the residential buildings in Yemen, which is in an arid climate. A suitable building envelope is important because of the building occupants’ thermal comfort. The most important question is how architects could implement high-performance envelope technologies in their designs, especially in residential buildings. These technologies have some basic principles which are applied differently from one region to another. One of the most promising strategies applied to house envelopes in a hot-dry climate is the passive cooling design. This thesis reviews the results of other research in the same region that discuss proper parameters of building envelopes such as form, width, climate, walls, materials, and windows design. Passive cooling strategies will be the key to providing potential design building envelopes that provide thermal comfort and reduce energy use. This study applies the natural ventilation principle (single-sided, cross- or stack ventilation), thermal mass, and shaded devices. The research methods were to collect data and create quantitative models to analyze the data. From this analysis, I suggest specific architecture guidelines for design in residential buildings which could improve comfort in indoor spaces for occupants.
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The Feasibility of Double-Skin Façades to Provide Natural Ventilation in Tall Office Buildings
Title
The Feasibility of Double-Skin Façades to Provide Natural Ventilation in Tall Office Buildings
Creator
Kim, Yohan
Date
2022
Description
Many tall office buildings (i.e., buildings of or taller than 656 ft (200 m)) are on the rise around the world. The energy efficiency and...
Show moreMany tall office buildings (i.e., buildings of or taller than 656 ft (200 m)) are on the rise around the world. The energy efficiency and healthy environment of tall office buildings has become an important concern, given the current environmental challenges and health considerations. Natural ventilation has proven to be an effective passive strategy in improving energy efficiency and providing healthy environments given environmental challenges. However, such a strategy has not been commonly adopted to tall office buildings that traditionally rely on single-skin façades (SSFs), due to the high wind pressure that creates excessive air velocities and occupant discomfort at upper floors. Double-skin façades (DSFs) can provide an opportunity to facilitate natural ventilation in tall office buildings, as the fundamental components such as the additional skin and openings create a buffer to regulate the direct impact of wind pressure and the airflow around the buildings. Wind-driven natural ventilation has not been fully studied in DSFs as most previous studies focused on the stack effect. Moreover, the studies assumed that the indoor spaces are mechanically ventilated without regard to airflow behavior between the air cavities and the indoor spaces. This study investigates the impact of modified multi-story type DSFs on indoor airflow in a 60-story, 780-foot (238 m) naturally ventilated tall office building under isothermal conditions. Therefore, the performance of wind effect related components was assessed based on the criteria (e.g., air velocity and airflow distribution), with respect to opening size, number of openings per floor, cavity depth, and cavity segmentation. Computational fluid dynamics (CFD) software was utilized to simulate outdoor airflow around the tall office building, and indoor airflow at various heights in case of various DSF configurations. Two sequential CFD simulations were carried out not only to reduce computational time, but also to comprehensively analyze the impact of DSFs responding to positive and negative wind pressures on indoor airflow behavior. The CFD simulation results indicate that the outer skin opening is the more influential parameter than the others on indoor airflow behavior. On the other hand, variations of inner skin opening size help improve the indoor airflow, with respect to the desired air velocity and distributions. Despite some air vortexes observed in the indoor spaces, cross ventilation can occur as positive pressure on the windward side and negative pressure on the other sides generate a productive pressure differential. The results also demonstrate that DSFs with smaller openings suitably reduce not only the impact of wind pressure, but also the concentration of high air velocity near the windows on the windward side, compared to single-skin façades. Further insight on indoor airflow behaviors depending on various DSF configurations leads to a better understanding of the DSF design strategies for effective natural ventilation in tall office buildings. This study aims to develop a performance-based DSF design guideline to assist architects in their design of DSF components in the early design stage.
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