UNIVERSITY OF ARCHITECTURE HO CHI MINH CITY ---PHAN TIEN VINH NATURAL VENTILATION EXPLOITATION IN RISE HOUSINGS IN THE CITIES OF THE SOUTH CENTRAL COAST REGION TOWARDS ENERGY SAVING - SU
Trang 1UNIVERSITY OF ARCHITECTURE HO CHI MINH CITY
-PHAN TIEN VINH
NATURAL VENTILATION EXPLOITATION IN RISE HOUSINGS IN THE CITIES OF THE SOUTH CENTRAL COAST REGION TOWARDS ENERGY SAVING - SUSTAINABLE DEVELOPMENT
HIGH-Major: ARCHITECTURE Code: 9.58.01.01
SUMMARY OF DOCTORAL THESIS OF ARCHITECTURE
Ho Chi Minh City – 2019
Trang 2Science Instructor: Assoc Prof PhD Arch TRINH DUY ANH
Reviewer 1: Reviewer 2: Reviewer 3:
The thesis is protected in front of the University-level Thesis ExaminationBoard in: UNIVERSITY OF ARCHITECTURE HO CHI MINH CITY
At ……… on ……….……
The thesis can be investigated in the library:
UNIVERSITY OF ARCHITECTURE HO CHI MINH CITY LIBRARY
HO CHI MINH CITY GENERAL SCIENCE LIBRARY
Trang 3INTRODUCTION 0.1 THE NECESSSITY OF THE RESEARCH
From the middle of the 20th century, mankind has faced many global challenges, including energy, resources, environment, poverty, global climate change, In that context, sustainable development in general and sustainable architecture in particular, have become an essential trend of most countries in the world and Vietnam as well
Sustainable architecture is the architecture that aims at environmental adaptation and sensitivity, reasonable use of resources and energy, environmental friendliness and contributing to the ecological environment conservation throughout the life cycle of buildings There are many design solutions towards sustainable architecture, in which, natural ventilation (NV) for the purpose of energy saving and environmental friendliness is one of the most basic, effective and important solutions
The apartment building is a popular type of housing architecture in major urban areas in the world and Vietnam Currently, the effective exploitation on NV in high-rise housings (HRHs) projects in Vietnam has still some disadvantages
The South Central Coast region (SCCR) have many large urban that are under the development phase and many HRHs projects This region has significant potentials and needs on NV in HRHs NV exploitation in HRHs in the SCCR towards energy saving will contribute to the sustainable development for architectures in particular and this region in general
Therefore, the subject of this thesis is “Natural ventilation
exploitation in high-rise housings in the cities of the South Central Coast region towards energy saving - sustainable development”
0.2 RESEARCH OBJECTIVES
- Overall research objectives: exploiting NV in HRHs in the cities of the SCCR in order to save energy, towards sustainable development for
Trang 4type of HRH architecture in particular and sustainable development objectives for Vietnam in general
- Specific research objectives: The orientation, design principles, and recommendations on exploiting and operating NV in HRHs in the cities
- Space scope: the cities of the SCCR;
- Time scope: from the present to 2030 and the vision to 2050
0.5 SCIENTIFIC AND PRACTICAL MEANINGS OF THE THESIS
- Scientific meanings: The thesis provided a design methodology, some general design principles on NV in HRHs towards energy saving and sustainable development Thereby, this thesis contributes to the design theory of NV in buildings in general and HRHs in particular
- Practical meanings: The research results could be applied for the design practice of the SCCR, contributes to the energy saving, the sustainable development of HRHs architecture and the SCCR This research provides a useful document for architect training, and references for urban planning managers, designers, investors,
Trang 5CHAPTER 1: OVERVIEW OF NATURAL VENTILATION EXPLOITATION IN HIGH-RISE HOUSINGS TOWARDS ENERGY SAVING - SUSTAINABLE DEVELOPMENT 1.1 SUSTAINABLE DEVELOPMENT AND SUSTAINABLE ARCHITECTURE
1.1.1 History and definitions of sustainable development
When the development of humanity results to global challenges for the ecological environment and affects the survival of future generations, nations on the world need to have thoughts and actions to save the earth,
in order to ensure the survival and development of future generations Sustainable development is defined as the development that meets the needs of the present without compromising the ability of future generations to meet their own needs To achieve true sustainability, it must be balanced social, environmental and economic sustainability factors
1.1.2 Sustainable architect
Sustainable architecture is an architecture that seeks to minimize the negative environmental impact of buildings by efficiency and moderation in the use of materials, energy, and development space and the ecosystem at large
1.1.3 Sustainable architect development in Vietnam
For traditional Vietnamese housing architecture, our ancestors have
accumulated experiences such as: “marrying should look for a gentle
wife, building should choose a South-facing house”, “areca trees in the front and bananas trees behind the house”, using "phen dau" to protect
from the sun, use the porch as a transition space, using the trees and waters factors to improve the microclimate for indoor environment, etc
In the construction field, the state management agencies have issued many legal documents and implemented activities towards sustainable development Many organizations that reseaching and operating in suitainable architectures field have been established in Vietnam
Trang 61.2 HIGH-RISE HOUSINGS ARCHITECTURE
1.2.1 High-rise housings
HRHs are high-rise apartment buildings or high-rise complexs that have the housing function, have from 9 floors to 40 floors The advantages of HRHs are land saving, low density of construction, high coefficient of land use, modern, suitability to modern and urban lifestyle, etc The disadvantages are the difficulty in escape in emergency case, complicated structure; causing some negative impacts on the environment and on the psychology of residents
1.2.2 High-rise housings in the world, Vietnam and the cities of the South Central Coast region
From the end of the nineteenth century, the developments of the economy, society, science, and technology, the population explosion and the urbanization process have resulted in the appearance of high-rise architecture as an architecture trend in the world
According to "National Housing Development Strategy from the
present to 2020 and the vision to 2030", apartment buildings which
include HRHs is housing type that need to be strongly developed in the urban areas in Vietnam
Many HRHs projects have been constructed in the SCCR, especially
in some big cities such as Da Nang, Nha Trang, Quy Nhon, etc
1.3 NATURAL VENTILATION IN BUILDINGS
1.3.1 Ventilation in buildings
Ventilation in buildings have the function making the indoor environment (including its parameters of temperature, humidity, air movement, air composition, etc) meet the comfort requirements of the
residents in buildings
Two types of ventilation include NV and mechanical ventilation
1.3.2 Natural ventilation in buildings
NV is a phenomena of air moving in buildings under the wind driven pressure and the air buoyancy pressure
Trang 7Wind is a physical phenomenon that changes randomly and does not follow any rules The wind velocity varies according to heights and is determined by the law of logarithmic functions or exponential functions Two types of NV in buildings are wind driven ventilation and stack ventilation
The roles of NV are to increase the exchange air volume, energy saving, speed up the air movement, limit the wind blowing into the room when conditions are not met; increase the areas of the room that has the wind blowing; create the friendly environment, etc
1.4 THERMAL COMFORT IN BUILDINGS
1.4.1 Thermal balance equation between human body and enviroment
In human bodies, most biochemical processes that related to cell production, energy metabolism, and physical work produce heat The heat exchange forms between the human body and the surrounding environment include convection, heat conductivity, radiation, and evaporation
The heat balance equation between the human body and the surrounding environment is showed as: M = NBH ± NĐL ± NDN± NBX± NT
1.4.2 Definition of thermal comfort
Thermal comfort is defined as “the condition of feel that expresses the
satisfaction with the thermal environment and is assessed by subjective evaluation of human”
The factors that influence thermal comfort include air temperature, mean radiant temperature, vapour pressure of water, air velocity, clothing insulation, metabolic rate, age, sex, the race, time in the day, location, eating habits, etc
Trang 81.4.3 Thermal comfort forecasting models: steady state comfort
model, two-node model, adaptive model
SUSTAINABLE DEVELOPMENT
1.5.1 The use of energy in buildings
Energy used in buildings include energy that be consumed throughout the life circle of the buildings: construction stage, operation stage, and demolition stage
1.5.2 Energy savings and efficient energy use in buildings
The energy savings and efficient energy use in buildings have become urgent and an inevitable trend in construction development towards sustainable development
1.5.3 Energy saving and sustainable development problems in construction
Energy saving plays an important role in ensuring energy security, reducing greenhouse gas emissions, protecting the ecological environment, and the reasonable use of energy resources Therefore, energy saving is one of the essential solutions in the sustainable development strategy of nation in general and construction field in particular
1.5.4 Natural ventilation exploitation in buildings towards energy saving - sustainable development
NV exploitation in HRHs towards energy saving and sustainable development includes the selections of construction location, the design solutions (planning and architecture), choices the NV strategy, and the operation solutions in order to maximal exploitation of natural resources
Trang 91.6 LITERATURE REVIEW
1.6.1 Research articles, research topics, and presentations at academic conferences mentioned on basic theories, models, design
solutions and standards, and applications of NV
1.6.2 The theses mentioned basic issues, principles and models,
thermal comforts, the effect of energy saving, recommendations on the design and on the exploitation, the application of models and methods on
NV researchs, etc
1.6.3 Overall comments after literature review: No studies have
done about “Natural ventilation exploitation in high-rise housings in the
cities of the South Central Coast region towards energy saving - sustainable development”
1.7 RESEARCH GAPS
1.7.1 The gaps about NV exploitation in HRHs in the cities of the South Central Coast region
- The NV exploitation has not been interested in;
- Evaluations of the NV exploitation potential;
- Orientations to the NV exploitation in HRHs;
- Design principles aimed at effectively NV exploitation in HRHs;
- Solutions to operate the NV systems in HRHs
1.7.2 Main research problems of this thesis
- The orientation of NV exploitation in HRHs in the cities of the SCCR towards energy saving, sustainable development
- Proposing some design principles to effectively exploit NV in HRHs
in the cities of the SCCR towards energy saving, sustainable development
- Proposing some operation solutions of NV systems in HRHs in the cities of the SCCR towards energy saving, sustainable development
Trang 10CHAPTER 2: RESEARCH METHODS AND SCIENTIFIC BASIS FOR NATURAL VENTILATION EXPLOITATION IN HRHS IN THE CITIES OF THE SOUTH CENTRAL COASTAL REGION 2.1 RESEARCH METHODS
This thesis utilizes some methods, actual survey and monitoring methods, sociological survey method, analysis - synthesis methods, modeling method, simulation on computers method, empirical survey method
2.2 SCIENTIFIC BASIS
2.2.1 The legal basis include legislation on sustainable development,
legislation on the architectural design towards energy efficiency, building codes and design standards of HRHs
2.2.2 The theoretical basis include architectural design for HRHs,
NV calculation, thermal comfort models, climate analysis of architectural design, architectural and technical design solutions, wind comfort and wind velocity, Computational Fluid Dynamics method and the use of simulation programs
2.2.3 The practical basis includes geographical location, topographical characteristics and climate characteristics, the development orientation of HRHs; the current exploitation of NV in HRHs; the application of Green Building assessment tools
2.2.4 Some lessons learned from the NV exploitation in housing
architecture in Vietnam, China and Singapore
Trang 11CHAPTER 3: RESEARCH RESULTS
3.1 THE ORIENTATION OF NATURAL VENTILATION EXPLOITATION
3.1.1 Determining the time when weather conditions are suitable for exploiting natural ventilation in buildings
- Da Nang city: Total number of hours in a year that needs cooling ventilation exploitation to meet the comfort conditions is 5.124 (hours)
- Quy Nhon city: Total number of hours in a year that needs cooling ventilation exploitation to meet the comfort conditions is 6 067 (hours)
- Nha Trang city: Total number of hours in a year that needs cooling ventilation exploitation to meet the comfort conditions is 6 863 (hours)
3.1.2 Proposing a comfort wind velocity to exploit the natural ventilation in HRHs in the cities in the South Central Coast region
The comfort wind velocity for residents of SCCR at high temperature and high humidity conditions is the ranges of velocities from 2.1 m/s to 2.4 m/s
3.1.3 Proposing the ventilation and cooling strategy in HRHs in the cities in the South Central Coast region: is full-day ventilation and
continuously for 12 months of the year
EXPLOIT NATURAL VENTILATION IN HIGH-RISE HOUSINGS IN THE CITIES OF THE SOUTH CENTRAL COASTAL REGION
3.2.1 The application of simulation tools in design
By using simulation tools, the efficiency of NV in HRHs is assessed
by quantitative data and visual images These important data and images help designers to timely adjust their design ideas for the purpose of optimizing the NV efficiency in the operation of buildings Therefore, giving design ideas and using simulation tools need to be coordinated in the design stages
Trang 123.2.2 Floor plan design
- Floor plan shape: choices group of rectangular plan forms;
- Functional subdivision solutions on typical floor plans - based on the technical transport core layout: focus in the middle; dispersing 2 premises; scattered in the middle of the ground
- Spaces in a typical apartment are arranged into layers:
+ Space layer 1: loggia, balcony;
+ Space layer 2: bedroom, living room;
+ Space layer 3, 4: Bedroom, dining room, kitchen, toilet, etc; + Space layer 5: kitchen, toilet, storage room
- The room size: a and b are respectively shown as the width and the depth, the relation of the dimensions is K (K = b/a) The value of K should be (or nearly) 1.5;
- The form of a typical floor plan: using the middle-open corridor plan form or the form of combining a middle-open corridor plan and courtyards;
- Loggia solutions: should use loggia for apartments;
- Orientation to use the partitions to divide space of apartments: limit
on using the wall; use the open spaces; use the porous partition; etc
- The orientation to design of interior: restrict the use of objects that occupy large areas, use types of objects that allow the wind blows through, etc
3.2.3 Designing of three-dimensional shape
Three-dimensional shape of the HRHs should be rectangular cubic shapes to effectively exploit the NV In addition, there should be solutions to design the blocks of HRHs, such as making the hollow spaces on the blocks, making the base for the blocks, chamfering the corners of the building base, etc
Trang 133.2.4 Design of master plan
Select the optimal angle for angle of wind direction to the building' surface (α) for effective natural ventilation in the apartments:
the α value ranges from 67.5° to 78.75°
Choices the direction of building
- Steps to choose the direction of building:
+ Step 1: Analyze the sun path Select the building's direction to minimize the sunshine and solar radiation impact
+ Step 2: Select the main direction of the apartment building to minimize the total of solar radiation on its two vertical surfaces
+ Step 3: Proposing the building's direction to maximize the wind frequency on its two main vertical surfaces and optimal angle value α + Step 4: Select the optimal building's direction for HRHs from above results
- Case study about choices the direction of building for the HRBs in
Da Nang city: (1) Southern South West – South – Southern South East; (2) Southern East South – EastSouth
Determining the width of recirculating wind areas after rise housing blocks
high-The thesis has provided the datas for the determination of the width
of recirculating wind areas after high-rise housing blocks and proposed
a calculated tool by Excel
Common principles and orientations of master plan design of HRH zones to effectively exploit the NV
- Forms of master plan layout and design orientation to increase the
NV efficiency: the single block layout (consists of only one single building block), the linear blocks layout (continuous and separate forms), the group blocks layout (parallel form, staggered form, perimeter form, mixed form, and free form)
- Some principles of master plan design: appropriate, effectiveness in operation and adaptation to natural conditions; harmony with the