China Mining University

School of Mechanics and Civil Engineering

"Introduction to Specialty" Course

Special thesis on building environment and equipment engineering direction

Topic: Architectural Wind Environment and Its Realization of Natural Ventilation, Architectural Design and Architecture

Layout format

My surname is Yang Xiaogang.

Civil engineering 09-65438 +0

Student number 02090428

Term: 10- 1 1 the first semester of the school year.

Teacher Huang Wei

20 10 65438+ February

Architectural wind environment and its architectural design and layout form to realize natural ventilation

Category: Civil Engineering 09-1 CategoryNo.: 02090428 Name: Yang Xiaogang

The inevitability of the birth of the new discipline of building environment and equipment engineering, the importance of building environment, the wind environment of buildings, the rational use of hot pressure and wind pressure to realize natural ventilation, the application of natural ventilation in architectural design, conclusions and references.

Key words: building wind environment, natural ventilation by hot pressing and wind pressure, layout form of buildings, layout mode of building communities, natural ventilation.

1. The birth, development and bright future of building environment and equipment engineering

After listening to the lecture on professional introduction for half a semester, I learned that civil engineering has become a comprehensive subject today. Detailed division of labor, mature system. And a relatively complete theoretical system. The rapid development of natural science and social economy provides rich theoretical guidance and special equipment for the development of civil engineering. At the same time, it is consistent with the goal of improving people's daily life with higher quality and higher efficiency. In the macro environment, it is playing an increasingly irreplaceable role and contribution in the global ecological environment protection while continuously developing the economy. At the same time, the continuous development of economy and culture has also expanded the scope of civil engineering. The progress of social informatization makes it easier for engineers to save, exchange and pass on their experiences. The accumulation of experience has also created conditions for theoretical breakthroughs. With the development of the times and the expansion of cities, modern architecture changes with each passing day. It is no longer the rigid bungalows and low-rise buildings in the past, and a large number of new building systems appear, which also puts forward more and higher requirements for internal equipment. Therefore, there is an urgent need for senior engineering and technical personnel who can adapt to the development of modern architecture. In China, the internal environment and equipment of some new buildings are still unsatisfactory, and many aspects are still in the stage of exploration and trial. For example, some high-rise office buildings and ornate buildings have obvious problems such as poor ventilation leading to a decline in air quality, or insufficient cooling in summer and insufficient heating in winter. Building environment and equipment engineering, as a new discipline, was born with people's pursuit of quality of life. The specialty of building environment and equipment engineering is a newly established specialty in the new enrollment catalogue formulated by the Ministry of Education 1998, which is formed by the merger and reorganization of the original specialty of heating, gas supply, ventilation and air conditioning engineering and the specialty of gas transmission and distribution. Internationally, this major has developed very rapidly, which is reflected in the broadening of the field and the wider scope involved. This major has developed into comprehensive knowledge such as physiology, psychology, meteorology, ecology, urban planning, architectural design, sociology and aesthetics. , and tend to be interdisciplinary subjects. At the same time, the introduction of computer depth into this major is conducive to the development of this major into a very cutting-edge discipline. In the new century, health, energy and environment have become three major themes that people pay attention to, and the building environment is closely related to equipment specialty and these three aspects. With the increasing awareness of environmental protection tomorrow, this major has important research and application prospects.

1. 1 Birth and development status of the built environment

Man is a part of nature. Throughout the ages, under various natural conditions, human society has always created and improved the living environment of God. A long time ago, people were faced with how to protect themselves and how to survive in a harsh environment. The process from Chaozhou Opera, cave dwelling, drilling wood for fire scattered in the wild to building houses in settlements is a true portrayal of human efforts to adapt to nature, use nature, transform nature and make unremitting efforts to improve the living environment.

With the progress of society, the development of social productive forces and science and technology, on the one hand, human's ability to control the built environment has been greatly enhanced; On the other hand, human life is becoming more and more colorful, which requires active control of building environment and safety technology from a high level, and the discipline of building environment and equipment engineering has developed accordingly, which also makes HVAC gradually form and develop.

Building environment and equipment engineering is a new discipline which combines theory and practice perfectly, and it is rich in content. Specifically, it is the general name of various facilities and equipment systems that provide life, production and work services for building users, and it is an indispensable and important condition for realizing modern building functions. Including water supply, drainage, fire protection, heating, ventilation, air conditioning, power supply, lighting and other systems in the building. It is a professional technical course for architecture, architectural decoration, civil engineering, construction management and other majors. It is a comprehensive engineering discipline and a professional course that closely combines theory with practice. In order to meet the needs of people's daily life, construction equipment plays an increasingly important role in the construction industry. Based on my own knowledge and knowledge, I briefly analyzed the design principle of air conditioning (wind environment) and airflow in building environment and equipment engineering and the layout format inside and outside related buildings by consulting relevant materials.

The wind environment of a building is the flow of air in the space inside and outside the building and its influence on the use of the building. Wind is also an important part of modern architectural design. In the previous architectural design, the wind environment of the building was ignored or even ignored. Today, with more and more attention paid to the natural environment and living environment, the relationship between natural ventilation and human comfort and building energy saving is becoming more and more important, and it is gradually reflected in the practice of architectural design, especially in residential architectural design.

From the design point of view, there are two kinds of wind environment: natural ventilation and mechanical ventilation. Mechanical ventilation refers to the use of mechanical ventilation equipment to achieve indoor air circulation. Compared with natural ventilation, mechanical ventilation consumes more energy, and its application scope is limited to the interior of buildings, and it also produces noise, which brings comfort and pollution to the natural environment to a certain extent. Natural ventilation refers to the free flow of air in nature through functional spaces in residential groups and residential buildings. Natural ventilation can accelerate the air flow, bring coolness and take away pollution, especially in hot summer, which can improve the local climate. Therefore, from the perspective of health and energy saving, natural ventilation is more positive.

In architectural design and planning, different architectural forms and combinations will produce different ventilation effects. Through scientific building group layout and reasonable indoor functional space combination, natural air can flow in the smoothest way indoors and outdoors, so as to achieve the best natural ventilation effect.

Natural ventilation is a widely used ventilation method in today's buildings, and it is a technology to transform the thermal environment of buildings and save energy consumption of air conditioning. The fundamental purpose of adopting natural ventilation is to replace some air conditioning and refrigeration systems. This has two important meanings in the process of new generation replacement: perception, effective passive refrigeration and natural ventilation can reduce the indoor temperature without consuming non-renewable energy under the condition of low indoor temperature and humidity, and take away part of the gas in the supermarket to achieve comfortable heat and temperature for human body. Even if the outdoor air temperature and humidity moderately exceed the comfort zone, it needs to consume energy to reduce the temperature and humidity. Natural ventilation can also be used to transport the treated envelope, with no loss of mechanical energy and no noise. Conducive to reducing energy consumption and air pollution, in line with the idea of sustainable development. The second is. It can provide fresh and clean natural air, which is beneficial to human victory and mental health. The poor indoor air quality is mainly due to the lack of adequate envelope. The constant temperature environment caused by air conditioning also reduces the human body's resistance, causing various diseases such as "air conditioning disease" and other sub-health side effects. Natural ventilation can eliminate indoor dirty air and meet people's psychological needs of communicating with nature.

One is hot pressing and wind pressure to realize natural ventilation.

For a long time, ventilation, as a traditional building heat dissipation technology, has only been widely used in traditional residential buildings around the world. In tropical areas, people often see that traditional residents often live in houses with such appearance: buildings have open windows; Adopt light wall; Deep overhang; A high ceiling with vents; Buildings are often overhead. To avoid expired and hot air on the ground. The adoption of cooler air reflects the working people's understanding of the traditional simple concept of natural ventilation technology. Natural copper powder is a kind of ventilation mode with great potential, and it is the application of a more mature and environmentally friendly architectural concept gradually realized by human beings now and in the future.

The key to natural ventilation of buildings lies in the pressure difference between indoor and outdoor air. The causes of air pressure difference can be hot pressing and wind pressure respectively.

1. Using wind pressure to realize natural ventilation

Wind pressure refers to the static pressure generated when the airflow is blocked. In areas with good external wind environment, wind pressure can be used as the main means to realize natural ventilation. When the wind blows through the building, the windward airflow is blocked, and the static pressure increases due to the blocking of the building. The crosswind and leeward side will produce local eddy current, and the static pressure will decrease. In this way, a pressure difference is formed between the windward side and the leeward side, and the indoor and outdoor air flows from the high pressure side to the low pressure side under the action of this pressure difference.

In addition, Bernoulli fluid principle shows that the pressure of flowing air decreases with the increase of its velocity, thus forming a low pressure region. According to this principle, a transverse ventilation passage can be left locally in the building. When the wind blows through the channel, a negative pressure zone will be formed in the channel to drive the flow of the surrounding air. This is the ventilation principle of tubular buildings. The ventilation pipe channel should be closed in one direction and open in other directions, thus forming a clear ventilation direction. This ventilation method can achieve good ventilation effect in a large and deep building space.

2. Hot pressing to achieve natural ventilation.

Another principle of natural ventilation is to use the thermal pressure difference of the air inside the building-commonly known as "stack effect" to realize the natural ventilation of the building. Because the temperature difference between the air inside and outside the building produces the difference of air density, the pressure difference is formed, which drives the air inside and outside to flow. The air with high indoor temperature has a small specific gravity and rises, and is discharged from the upper air outlet of the building. At this time, a negative pressure zone will be formed in the original place of low-density air, so that fresh air with low outdoor temperature and heavy proportion will be sucked out from the bottom of the building, and indoor and outdoor air will flow continuously. The size of hot pressing depends on the height difference between the two vents and the air density difference between indoor and outdoor. In practical design, architects often use chimneys, ventilation towers, patios, atriums, etc. to provide favorable conditions for the use of natural ventilation, so that buildings have good ventilation effects.

3. Natural wind under wind pressure and hot pressing * * *

In actual architectural design, natural ventilation is the function of wind pressure and hot pressing, but their respective functions are strong and weak. Because the wind pressure is influenced by the weather, outdoor air, wind direction, architectural modeling, surrounding environment and other poppies, the interaction between elegance and hot pressing is not a linear superposition of single lines. Therefore, architects should fully consider various factors, that is, elegance and hot pressing complement each other and cooperate closely to realize effective natural ventilation of buildings.

4. Mechanical-assisted natural ventilation

In some large buildings, because of the long ventilation path and large flow resistance, it is often not enough to rely solely on natural wind pressure and hot pressing to achieve natural ventilation. Second, for cities with serious air pollution and noise pollution, direct ventilation will also bring dirty outdoor air and indoor noise, which will not touch human health. In this environment, mechanical auxiliary natural ventilation system is often used. The system has a complete set of circulation channels, supplemented by ecological air treatment means, such as soil cooling, preheating, deep well heat exchange and so on. And ventilate the hormone room in a certain way.

5. Natural ventilation on the roof

There are usually two ways of ventilation and thermal insulation: 1) Erecting an empty thermal insulation layer on the upper part of the structure. The ventilation layer is arranged on the sleepless structure layer, and the heat is taken away by the air interlayer in the middle, so as to cool the layer. In addition, the overhead board also protects the sleepless waterproof layer. 2) Using the structure of the roof itself, setting ventilation and heat insulation layer in the middle of the structural layer can also obtain better heat insulation effect.

2. The application of natural ventilation in residential design

The factors affecting natural ventilation are the height, depth, length and windward direction of the building itself; For building groups, there are the spacing, arrangement and combination of buildings and the windward direction of building groups; For the planning of residential areas, there are reasonable site selection and reasonable layout of roads, green spaces and water surfaces in residential areas to achieve the best ventilation effect. The following will be explained from several aspects.

2. 1 building orientation

To determine the orientation of buildings, we should not only know the direction with more sunshine, but also know the relevant characteristics of local winds, including the direction, speed and temperature of the dominant winds in winter and summer. Each area has its own wind characteristics, because the maximum pressure on the windward side of the building is on the plane perpendicular to the wind direction, so when choosing the direction of the building, the main facade of the building should be oriented towards the dominant wind direction in summer and the side facade should be oriented towards the dominant wind direction in winter. The south direction is the direction with the largest solar radiation. In addition, the dominant wind direction in summer in most parts of China is southerly or southeast wind. Therefore, no matter from the perspective of improving natural ventilation in summer, adjusting the thermal environment of the room, or reducing the heating and air conditioning load in winter and summer, the south direction is the best choice for building orientation. Moreover, choosing the south direction is also conducive to avoiding the east and the west, and both can be taken into account. For those buildings with unsatisfactory orientation, effective measures should be taken to properly solve the above two problems.

2.2 Building spacing

When the sunshine distance between north-south buildings is small, the front building blocks the rear building, so the wind pressure is small and the ventilation effect is poor; On the other hand, when the sunshine distance between buildings is large, the wind pressure of the buildings in the back row is strong and the natural ventilation effect is good. Therefore, in the design of residential group, increasing the spacing of some residential buildings to form a group green space will have a good effect on improving the natural ventilation of residential buildings on the leeward side of green space, and at the same time, it can provide a good place for people to rest and communicate.

At the same time, if conditions permit, try to increase the gable spacing. Because when the outdoor airflow blows through the building with determinant layout, air jets will be formed between the gables of the building. When staggered arrangement is adopted, the air jet between residential gables can be used to improve the downwind residence and natural ventilation, and the effect is remarkable. Gable spacing depends on residential spacing. The greater the distance between houses, the greater the distance between gables, so that there can be enough air jets to blow to the houses behind. The gable spacing of residential buildings is too small, which has adverse effects on fire fighting, greening and road traffic.

2.3 the layout of the building

The relationship between architectural layout and natural ventilation can be considered from two aspects: plane and space.

2.3. 1 From the point of view of plane planning, the layout of buildings can be determined, peripheral and decentralized.

Determinant is the most basic layout of buildings, which is a way that strip-shaped unit houses or townhouses are arranged in rows at a certain orientation and reasonable spacing, and its layout is parallel, staggered and oblique. The parallel layout is staggered, thus forming a staggered, oblique and peripheral layout.

Although the layout of parallel buildings has changed greatly because of the different projection angles of the wind direction, the overall wind surface is small; Staggered diagonal rows can lead the wind into the building complex from the oblique direction, and the wind surface of the downwind building is large, the wind field distribution is reasonable and the ventilation is good.

Peripheral residential buildings are arranged along the neighborhood or courtyard, forming a closed or semi-closed inner courtyard space, and the projection surface of wind is very small, which makes it difficult to draw wind. This arrangement is only applicable to cold areas in winter; Decentralized residence layout includes low-rise single-family residence, multi-storey point residence and high-rise tower residence layout. Decentralized residential buildings are organized by themselves or around the central buildings, public green spaces and water bodies of residential groups. At the same time, the design of road network is also in progress. Sometimes, square residential plots change the planning mode of residential roads in the past, boldly adopt the planning mode of replacing straightness with straightness, and artificially create different layout modes of building groups, thus creating ". At the same time, the main roads in the residential area are designed with main ventilation pipes, which flow to each residential group along the ventilation corridor, and then divert from the courtyard space in the group to the residence to accelerate the flow of natural wind. Originally, the layout of the building and road network was quite satisfactory, and the planning of the community was a bit dull. The deterministic layout of buildings makes the distribution of natural ventilation in residential areas uneven, and some buildings have poor ventilation. By adjusting the road network, the building layout is no longer a simple relationship between rows and columns, but interacts to form groups, and dense and sparse places are designed to be green among groups. Natural wind flows to each group through the main road, and then to each house through the green space between groups. Therefore, in the planning and design, we can make full use of natural wind to save energy and optimize the wind environment in the community.

The layout of buildings has great influence on the introduction of natural wind, and the relationship between wind direction and buildings also has great influence on the introduction of natural wind. The wind direction projection angle refers to the angle between the wind direction projection line and the normal of the building wall. For a single building, the smaller the wind direction projection angle, the better the room. However, for buildings, the influence of the wind shadow area formed by the front building on the rear building should be considered. Typical houses such as residential quarters are generally multi-row buildings arranged in parallel. If it is blown, the wind shadow area behind the house is large, which affects the natural ventilation effect. Therefore, it should be avoided that the long axis of the residence is perpendicular to the dominant wind direction in summer, so as to reduce the adverse effects of the front row residence on the ventilation of the rear row residence and form a good ventilation convection. Generally speaking, the best ventilation effect is to keep the incident angle between the house and the wind direction between 30 and 60.

2.3.2 From the perspective of facade design, it is necessary to make the single building orderly.

It is necessary to make the airflow pass through the community without forming bad high-speed airflow such as vortex and undershoot. When buildings are combined, when one building is much higher than other buildings or the distance between buildings is similar, the distance between two buildings suddenly increases, and then the downward flow increases, resulting in high-speed wind, which leads to increased heat loss and discomfort for residents.

Similarly, in the design, try to avoid the wind between buildings. The layout of buildings should follow the dominant wind direction in summer as far as possible, and the buildings near the dominant wind direction should be low-rise and multi-storey, at the edge of the community. Buildings far away from the dominant wind direction should adopt small high-rise buildings and high-rise buildings, so that on the one hand, natural wind can be introduced into the community, on the other hand, northeast wind in winter can be blocked.

label

Natural ventilation is a cheap ecological energy-saving technology. Architects should carefully consider the applicability and effect of natural ventilation from the whole process of architectural planning, building monomer design to structural design, effectively use natural ventilation to solve the problems of thermal comfort and air quality in houses, and create a healthy and comfortable living environment without increasing family investment. Building environment and equipment engineering involves a wide range of science and technology, high knowledge content and high professional requirements. I can't have a deeper understanding of it in a short time, but I believe I will learn more and more relevant knowledge through my continuous efforts.

References:

Architectural Physics, China Building Industry Press;

Analysis of Natural Ventilation Design of Buildings, Journal of chongqing jianzhu university;

Heating, Ventilation and Air Conditioning, Pro-University Press;

Ventilation and air conditioning engineering, machinery industry press, Xu Yong;

Automatic control of HVAC, Beijing University of Technology Press, Li Yanfeng;

Heating, fan air conditioning, chemical industry press;

Li Baizhan, Heating, Ventilation, Air Conditioning and Refrigeration Engineering, Chongqing University Press.