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MINISTRY OF EDUCATION MINISTRY OF AND TRAINING CONSTRUCTION UNIVERSITY OF ARCHITECTURE HO CHI MINH CITY - PHAN TIEN VINH NATURAL VENTILATION EXPLOITATION IN HIGHRISE HOUSINGS IN THE CITIES OF THE SOUTH CENTRAL COAST REGION TOWARDS ENERGY SAVING - SUSTAINABLE DEVELOPMENT Major: ARCHITECTURE Code: 9.58.01.01 SUMMARY OF DOCTORAL THESIS OF ARCHITECTURE Ho Chi Minh City – 2019 The work is completed in: UNIVERSITY OF ARCHITECTURE HO CHI MINH CITY Science 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 Examination Board 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 INTRODUCTION 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 type 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 of the SCCR 0.3 RESEARCH SUBJECTS - HRHs architecture; - The NV in HRHs 0.4 RESEARCH SCOPE - 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, CHAPTER 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 1.2 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 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 Wind 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 1.4.3 Thermal comfort forecasting models: steady state comfort model, two-node model, adaptive model 1.5 NATURAL VENTILATION EXPLOITATION IN BUILDINGS TOWARDS ENERGY SAVING – 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 1.6 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 CHAPTER 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 11 3.2.4 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 highrise housing blocks 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 12 landscape surrounding; meet the ideas of the spatial organization; create reasonable distances among blocks; meet the aesthetic requirements and other comfort, such as temperature, light, sound, air quality, etc - Design orientations of master plan layout types: + The single block layout and the linear blocks layout: the main direction of the block is determined according to natural conditions of the construction site and design ideas If the linear blocks layout does not ensure the effectiveness NV, architects should use some solutions, such as separate the blocks, adjust to get the optimal blocks' direction, create hollow spaces on the blocks, etc + The group blocks layout: choices the α value range from 22.5° to 45° in case of the parallel form, and the optimal α is equal to 22.5°; choices the α value range from 45° to 90° in case of the staggered form, and the optimal α is equal to 67.5°; choices the α value range from 67.5° to 90° in case of perimeter form, opening spaces on the blocks group face the prevailing wind, increase the area of opening spaces, etc; the mixed form along with the free form is a combination of the parallel form, the staggered form, and the perimeter form Some solutions to enhance natural ventilation efficiency on master plan - Creating hollow spaces on the blocks - Creating a base for the blocks, chamfering or filleting the corners of the building base, etc - Using the buildings' height planning solutions, layouting the blocks in the staggered form, choosing the α value which is suitable for the characteristics of master plan, etc - Green trees and water surface exploiting solutions; - The solutions on exploiting topographical factors 3.2.5 Design of building’ envelope Design the building’ envelope for NV need to be met: natural lighting, apartments' vision, and architectural aesthetics for the exterior of the 13 buildings; the porosity of the envelope decreases with the height of the building - it is proposed to change according to the floors group; the shape of the porosity on the building’ envelope can change its shape according to design ideas; etc In case of the building’ envelope are in different shapes, CFD software should be used to evaluate the effectiveness of NV From that, specific solutions can be proposed 3.2.6 Openings solutions for apartments Design of openings outside the apartments - Windows: the window solutions on the floor plan and the section is dispersed, low position The swing angle of the window should be from 45° to 75° - Doors: wing is located in the border position of the room; multiple wings are located on the middle of the door or dispersed evenly to the two edges of the door - The areas of windows for wind: need to change according to the height of the building The 40-floors buildings will have times to change the areas of windows of the floor groups of N1 (the area of this group is S1), N2, N3, N4, N5, N6, N7 and N8 The relative areas of the N2, N3, N4, N5, N6, N7 and N8 groups are: 76%; 69%; 64%; 61%; 59%; 57%; 55% in comparing to S1 Design of openings inside the apartments - Openings position: it creates wind field in the room and affects the wind velocity in the room When the air flow is through, the velocity will be higher than the velocity of the air that has to move around - The area of opening is calculated to regulate the wind field and the wind velocity in the room With the constant inlet opening areas, so that the wind field in the room is large, the area of openings needs to increase In order to reduce the wind velocity through a large room, the area of the outlet opening areas need to reduce 14 3.3 SOME OF RECOMMENDATIONS FOR OPERATION AND EXPLOITATION ON NATURAL VENTILATION FOR HIGH-RISE HOUSINGS IN THE CITIES OF THE SOUTH CENTRAL COAST REGION 3.3.1 Choices exploitation operation solutions There are two solutions to operate the NV system of buildings: manual operation and automatic operation For the HRHs, the thesis proposes to use the manual operation solution to open and close the openings system to let the wind in and out 3.3.2 Management solutions - The technical systems of the building are exploitated, repaired, operated and maintained by the Apartment Management Board - Openings in private spaces are operationed (opened and closed) by the residents in each apartments according to their individual needs - Openings in public spaces are operationed (opened and closed) by the Apartment Management Board or the residents - The smart openings systems (if any) are operated by the technical staff of the Apartment Management Board 3.3.3 Some of solutions to raise the residents’ awareness In order to have a highly effective on exploiting and operating NV in HRHs, occupant' awareness raising is very important, especially when choosing a manual operation solution Some solutions: providing basic information and knowledge; consultancy for HRHs' occupants; combining thematic talks in community meeting; introducing some actual apartments that have the high effectivenees on exploitation of NV; advising HRHs' occupants about operation solutions NV in apartments; etc 15 CHAPTER 4: DISCUSSION ON RESEARCH RESULTS 4.1 POSSIBILITY OF APPLICATION OF RESEARCH RESULTS OF THE THESIS ON HIGH-RISE HOUSINGS DESIGN REALITY IN THE CITIES OF THE SOUTH CENTRAL COAST The potential of NV exploitation in HRHs design in the SCCR is very large The actual survey shows that the demand for using NV in HRHs is very large The thesis has proposed some general principles on specific solutions of NV, methodology for NV design for HRHs These above principles and methodology - depending on the specific characteristics of each project - can easily be applied to the actual design process to provide a initial design plan with high efficiency in the NV exploitation 4.2 THE EFFICIENCY OF ENERGY SAVINGS AND SUSTAINABLE DEVELOPMENT GOALS IN ARCHITECTURE WHEN APPLYING THE RESEARCH RESULTS The total number of hours of the year that have comfort condition in the buildings of Da Nang, Qui Nhon, and Nha Trang are 3,207 hours, 3,626 hours and 4,137 hours, respectively In addition, with reasonable NV design solutions, the number of hours of the year that have comfort condition of cities Da Nang, Qui Nhon and Nha Trang can be increased by 1,917 hours, 2,441 hours and 2,726 hours This is also the time to save energy to use cooling devices The HRHs architecture type has a tendency to develop strongly and has a large number of projects investing in the big cities in the SCCR With the reasonable application of the research results of the thesis in the process of architectural design and the NV exploitation operation in the HRHs, the efficiency of energy saving is very large and increases proportionately with the number of apartments 16 4.3 POSSIBILITY OF APPLICATION OF RESEARCH RESULTS OF THE THESIS FOR OTHER CITIES IN VIETNAM Cities in Vietnam have many similarities Therefore, the scientific basis, general design principles and especially the methodology in design proposed by the thesis can be applied to the HRHs design in other cities in Vietnam In order for application the methodology and the research results of the thesis to other cities in Vietnam to be reasonable and effective, some additional studies on geographic location, characteristics of nature and climate, of urban areas (construction sites) need to 4.4 COMBINATION NATURAL VENTILATION AND UTILIZATION OF COOLING EQUIPMENTS WITH LOW ENERGY CONSUMPTION FOR ENERGY SAVING, FORWARD SUSTAINABLE DEVELOPMENT NV is a passive design solution Therefore, the design solution to exploit NV for apartments will not be as effective as the design at some time of day and in some locations in the apartment In order to enhance the efficiency and to increase the total time to apply the pure NV solution for apartments, the solution of combining NV and utilization of cooling devices with low energy consumption norms (such as table fan, ceiling fan , etc) is a reasonable solution in NV exploitation in HRHs With the strategy of full-day ventilation and continuously for 12 months of the year, the time to use these devices in the HRHs is continuous all year round 4.5 LIMITATIONS OF RESEARCH RESULTS - Researches are carried out under certain boundary conditions Therefore, when applied to practice, the result still have a minor error result compared to reality - The research results are based on the data of the big cities in SCCR (3 major cities: Da Nang, Qui Nhon and Nha Trang) Therefore, when 17 applying for other cities of Vietnam, it is necessary to continue additional researchs on the geographical position, natural conditions, climate, society, culture, etc - The thesis proposed a comfort wind velocity for the SCCR areas in high temperature and high humidity conditions - is the ranges of velocities from 2.1 m/s to 2.4 m/s This range of velocities is suitable for residents born and raised in the SCCR In conditions of high wind velocity (greater than 2m/s), it is important to note that the loss of steam may occur when residents are in this environment for a long time Therefore, it is necessary to have further researches on the limiting of the comfort time corresponding to each comfort wind velocity value under specific conditions of temperature and humidity 18 CONCLUSION The potential of natural ventilation exploitation in high-rise housings in the cities of the South Central Coastal region towards energy saving Cities in the SCCR have great potential in NV exploitation for HRHs The time of the year that the buildings meet the comfort conditions and the time of the year that the buildings need to ventilate to achieve the thermal comfort in three major cities of the SCCR is very large See Table KL1 Table KL1: Total number of hours in a year that have comfort conditions of Da Nang, Qui Nhon and Nha Trang The rate of comfort time in the Numerical order Number of City Da Nang 3.207 1.917 5.124 58.5% Qui Nhon 3.626 2.441 6.067 69.3% Nha Trang 4.137 2.726 6.863 78.3% Number of hours in the hours need to be ventilated Total comfort hours comfort to get (CZ + zone (CZ) comfort (VC) VC) year when having ventilation By reasonable NV design solutions, the total number of hours of the year that have comfort condition in the buildings in the SCCR can be very high Thereby, the energy saving effect used in the HRHs towards the sustainable development in the SCCR is very large The ventilation and cooling strategy in HRHs in the South Central Coast region: is full-day ventilation and continuously for 12 months of the year The comfort wind velocities for residents of the South Central Coast region 19 The thesis proposed the comfort wind velocities for for residents of the SCCR - in high temperature and high humidity conditions - is the ranges of velocities from 2.1 m/s to 2.4 m/s Some design principles of high-rise housings to effectively exploit natural ventilation - Floor plan design + Choices the group of rectangular plan forms for HRHs to achieve high efficiency in NV exploitation + The functional subdivision solutions on floors, on typical floor plans and in apartments depends on the specific characteristics of each project + The relation of the dimensions of the rectangular room is K (is the ratio between depth and width) Choices the K value is 1.5 or adjacent to this value + The appropriate typical floor plan form of HRHs in conditions of the cities in the SCCR in particular (and the cities in Vietnam in general) is middle-open corridor rectangular plan form Depending on the actual conditions and requirements of each project, it is possible to increase the areas of openings on the floor plan or incorporate this form with courtyards + In the HRHs design, it should design loggia for apartments The average wind velocity at the entrance (VTBx) of the design solution with loggia is higher than the solution without loggia This velocity increases proportionately with the height of the buildings + Orientation to use the partitions to divide space of apartments: minimizing the use of walls to divide space; prioritize the use the open spaces; use open partitions; in case of using closed partitions, it is necessary to locate the reasonable openings (window, door, etc) with functional requirements, aesthetic requirements and NV requirements 20 + Orientation to arrange of interior equipment in apartments: restricting the use of furnitures that surface have large areas; attention the air flows in and out; use furnitures with gaps; etc - Designing of three-dimensional shape + Choices rectangular cubic shapes for HRHs to effectively exploit the NV + There are solutions of design of three-dimensional shape of buildings, include: from one single block; combination from multiple blocks; combination the blocks in an order or symbolic image; random combination the blocks - Design of master plan + Select the optimal angle for angle of wind direction to the building' surface (α) for effective NV in the apartments: the α value ranges from 67.5° to 78.75° + Choices the direction of building are done in steps: analyze the sun path Select the building's direction to minimize the sunshine and solar radiation impact; select the main direction of the apartment building to minimize the total of solar radiation on its two vertical surfaces; proposing the building's direction to maximize the wind frequency on its two main vertical surfaces and optimal angle value α; 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 + The width (L) of recirculating wind areas after high-rise housing blocks in the case of changing the block sizes is shown in Table 3.14, Table 3.15 and Table 3.16 From there, the thesis proposes a tool by Excel to calculate the width L + There are types of master plan layout, include: the single block layout, the linear blocks layout, the group blocks layout (parallel form, staggered form, perimeter form, mixed form, and free form) 21 + Choices the forms of master plan layout should be based on natural conditions, architectural landscape, characteristic of buildings, design ideas, etc The values of α angle will give different NV effectives on master plan, such as: parallel forms have the best wind field on the master plan when the α angle is between 22.5° and 45°, and optimum when α = 22.5°; staggered forms have the best wind field on the master plan when the α angle is between 45° and 90°, and optimum when α = 67.5 °; perimeter form have the best NV effectives when the α angle is between 67.5° and 90°, opening spaces on the blocks group should face to the prevailing wind, increase the area of opening spaces, etc + Some solutions to enhance NV efficiency on master plan: creating hollow spaces on the blocks; creating a base for the blocks, chamfering or filleting the corners of the building base, etc; using the buildings' height planning solutions; green trees and water surface exploitation; topographical factors exploitation - Design of building’ envelope + The characteristics on shape and size of the building’ envelope decide to characteristics of wind fields after the building’ envelope + Average wind velocity (VTB) is directly proportional to the porosity of the building’ envelope and depends on the thickness of the building’ envelope + Design the building’ envelope for NV need to be met: natural lighting, apartments' vision, and architectural aesthetics for the exterior of the buildings, the porosity of the envelope decreases with the height of the building - it is proposed to change according to the floors group (5 foors/a group), the shape of the porosity on the building’ envelope can change its shape according to design ideas, etc - Design of openings outside the apartments 22 + Windows: wind field and wind velocity value change depending on apartment' characteristics, apartment location, the α angle, window location for air out, position of opening on the plan, etc When the window solutions on the floor plan is dispersed, there will be a wind field evenly distributed and a low average wind velocity On section of window, choices the low position to be effective for the user in the room and choices the dispersed solution to create a wind field evenly distributed for the room The swing angle of the window should be from 45° to 75° + Doors: characteristics of wind field depend on the incoming wind angle (α) and doors position In the case of two-wings openings, when the doors is central arranged or dispersed, the room will have a wind field evenly distributed; when the door is located at the edge of the room, the velocity in the room will reach maximum In the case of one-wing openings, the wind field depends on the α angle and the doors position; when the door is located at the edge of the room, the velocity in the room will reach maximum Proposing solutions of doors in HRHs: located at the edge of the room with one-wing openings solutions; located at the centre or dispersed to the two edges of the room with many-wings openings solutions + The areas of openings: for HRHs, the difference in incoming wind velocity values Vv between floors is quite large Therefore, this areas need to be changed according to the height of the building The 40-floors buildings should have times to change the windows areas of the floor groups of N1 (the area of this group is S1), N2, N3, N4, N5, N6, N7 and N8 The relative areas of the N2, N3, N4, N5, N6, N7 and N8 groups are: 76%; 69%; 64%; 61%; 59%; 57%; 55% in comparing to S1 - Design of openings inside the apartments + The relation between position of door for air out and door for air in has the effect of creating a wind field in the room and the affecting 23 on wind velocity in the room When the air flow is through, the air flow velocity will be higher in the case of the air flow moving zigzag During the design of openings inside the apartments, it should be noted this relative position - see Table 3.36 + The area of the openings affects on the air flow volume in the room, the air flow velocity through the room In the design, the area of the openings for air out is calculated to regulate the wind field and the wind velocity in the room, such as: with the area of the openings for air in is constant, increase the openings area to have a wind field evenly distributed; to have large wind velocities acrossing the room, it is necessary to reduce the area of the openings for air out + Orientation to design some types of openings in apartments: the main entrance door have a significant role to determine the NV type on apartments which are single-side ventilation or cross ventilation Therefore, the main entrance door should have of layers, including: hollow layer and solid layer The door layers are closed and opened flexibly according to the purpose of use to create the cross ventilation for the apartment When the solutions are wind driven ventilation and stack effect ventilation, the openings facing the courtyard or the corridors have the role of openings for air out These openings should have layers as the main entrance door to flexibly use and effectively exploit on NV for apartments The openings on the partitions should have a reasonable positions to catch the wind in, regulate the wind field and the wind velocity in the room, etc Some main solutions on operation and exploitation - There are two solutions to operate the NV system of buildings: manual operation and automatic operation For the HRHs in the SCCR, the thesis proposes to use the manual operation solution - Management solutions: opening groups needing to be operation in HRHs are openings in public spaces and openings in private spaces The openings in private spaces are operationed by the residents and the 24 openings in public spaces are operationed by the Apartment Management Board or the residents - In order to have a highly effective on exploiting and operating NV in HRHs, occupant' awareness raising is a very important problem RECOMMENDATION - Further researchs need to to propose the comfortable wind velocities for other geographical areas of Vietnam Since then, proposing comfortable wind velocities for Vietnamese people correspond with different climatic and geographical regions in Vietnam - Further researchs on the characteristics of geographical location, climate of the Northern Delta, Southern Delta, need to to be able to apply the research results of the thesis into actual design and actual construction of HRHs in the big cities of this region, such as Ha Noi, Hai Phong, Ho Chi Minh City, Binh Duong, Can Tho, etc - Management agency need to soon promulgate legislation documents on the application of NV design solutions for the HRHs to save energy in practice These documents are basis for designers to implement At the same time, it is necessary to have priority mechanisms for projects designed for effective NV, such as land prices, land use tax, corporate income tax, etc - Suitainable architecture problem need to be a compulsory subject in architect training The content of NV in HRHs is a self-selected subject for architecture students This content is also a reference document for designers, architectural managers and planning investors during the implementation of the project WORK LIST OF THE AUTHOR I The articles were published in the domestic scientific journals Tien Vinh Phan (2014), “Design solutions to the improvement of natural ventilation for Low-rise apartment buildings in Danang city”, Journal of Science and Technology - The University of Danang (ISSN 1859-1531), Vol I, Issue 6(79), pp 72-76 Tien Vinh Phan, Duy Anh Trinh, Anh Tuan Nguyen (2016), “Assessing the efficiency of outdoor natural ventilation in apartment building areas at master plan designing stage by the CFD method”, Construction and Urban Magazine (ISSN 18593119), Number 48 2016, pp 80-84 Tien Vinh Phan, Duy Anh Trinh, Anh Tuan Nguyen (2016), “Choices of building orientation in designing high-rise apartment buildings in Danang toward sustainable architecture”, Journal of Science and Technology - The University of Danang (ISSN 18591531), Number 11(108), Volume II, pp 269-273 Anh Tuan Nguyen, Thi Kim Dung Le, Tien Vinh Phan (2016), “Applications of optimization methods in designing energy-efficient buildings”, Science & Technology development Journal, Vietnam National University Ho Chi Minh city – Engineering & Technology (ISSN 1859-0128), Number 19(3), pp 98-106 Anh Tuan Nguyen, Thi Kim Dung Le, Tien Vinh Phan (2016), “Assessment of environmental quality in the low income apartments in Danang in summer”, Science journal of Architecture & Construction – University of Architect Hanoi (ISSN 1859-350X), Number 23, pp 20-25 Tien Vinh Phan (2016), “Proposal the relation of the dimensions of the room to enhance the natural ventilation efficiency for apartment in hight-rise apartment bulding”, Journal of Science and Technology - The University of Danang (ISSN 1859-1531), Number 11(120), Volume III, pp 117-121 II The articles were published in the Proceedings of the International Conferences Tien Vinh PHAN, Duy Anh TRINH, Anh Tuan NGUYEN (2018), “Comparing the natural ventilation efficiency of typical floor plan configurations in high-rise apartment buildings in Vietnam”, The VII International Scientific and Technical Conference “THE SOLUTION OF ENVIRONMENTAL PROBLEMS IN THE CONSTRUCTION INDUSTRY AND REAL ESTATE”, no: ISBN 978-5-4323-0261-8, pp 31-32 III Scientific subjets The university of Danang level scientific subject: "Proposed research some designing solutions for high-rise apartment building in Danang city from the perspective of green architecture in stage to 2030" Project leader: Tien Vinh Phan, Member: Thien Huong Luu Code: D2013 - 06 - 09 Acceptance year: 2013 Grassroots level scientific subject: "Proposed some designing and operation solutions for natural ventilation in high-rise apartment building in Da Nang city" Project leader: Tien Vinh Phan Code: T2016 - 06 - 35 Acceptance year: 2016 Grassroots level scientific subject: "Assessing the natural ventilation efficiency of typical floor plan configurations in high-rise apartment buildings designed toward sustainable architecture in Vietnam" Project leader: Tien Vinh Phan Code: T2017 - 06 75 Acceptance year: 2018 The university of Danang level scientific subject: "Researching and applying the optimization method into housing design for low-income people " Project leader: Nguyen Anh Tuan, Member: Thi Kim Dung Le, Tien Vinh Phan Code: D2013 - 06 - 09 Acceptance year: 2013 ... geographical areas of Vietnam Since then, proposing comfortable wind velocities for Vietnamese people correspond with different climatic and geographical regions in Vietnam - Further researchs... Tien Vinh PHAN, Duy Anh TRINH, Anh Tuan NGUYEN (2018), “Comparing the natural ventilation efficiency of typical floor plan configurations in high-rise apartment buildings in Vietnam”, The VII International... 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