2. Collect relevant design data, design manuals, design measures, design specifications and product samples.
3. Check the indoor and outdoor design meteorological parameters and calculate the cooling and heating load of the air conditioner.
4. Select and determine the air conditioning scheme: air conditioning mode, cold and heat source scheme and system control scheme.
5. Equipment selection calculation and determination of technical parameters, mainly cold and heat source host and air conditioning terminal equipment.
6. System layout, mainly equipment and pipeline layout.
7. System hydraulic calculation
8. Selection calculation and model determination of fans, pumps and auxiliary equipment.
9. Smoke control design and calculation
10. Draw drawings
1 1. sort out the design instructions and calculation instructions,
12. Submit graduation design results.
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Air conditioning (including refrigeration station and smoke control design)
Graduation design guidance
First, the purpose of graduation project
The purpose of graduation project is to improve students' ability to solve practical problems by using the theoretical knowledge they have learned. Therefore, students need to give full play to their subjective initiative, solve problems encountered in design as much as possible, and learn to use existing design reference materials. This guide book is only used as a reference for students to carry out graduation design.
Design methods and steps
Design preparation stage, collect relevant information.
(1) Familiar with relevant design codes and standards.
The design of air conditioning engineering should comply with the relevant design specifications, construction acceptance specifications, design technical measures, drawing standards and relevant local technical regulations and laws. Before starting the graduation project, you should collect these materials and be familiar with its main contents.
(2) Collect relevant product samples
The design of air conditioning engineering (including refrigeration, heating station, smoke control and ventilation) is generally applicable to the following main equipment and accessories: refrigeration unit, including compression type (piston type, centrifugal type and screw type) and absorption type (single, double-effect type and direct-fired type), including water-cooled and air-cooled type, including single chiller and hot and cold water heat pump; Air processors, including combined units, variable air volume units, fresh air units, fan coil units, unit air conditioning units, etc. Cooling tower, heat exchanger, oil-fired and gas-fired boiler, distribution main pipe, decontamination device, circulating water pump, fan, automatic exhaust valve, air volume control valve, fire valve, air return port, thermal insulation material, muffler, water filter, pressure reducing valve, steam regulating valve, etc. Before the design begins, the relevant sample data of the above equipment components should be prepared.
(3) Prepare relevant design manuals and standard atlas.
See "Resources" for design manuals, specifications and measures. The design of air conditioning project will use the following standard atlas: expansion water tank, distribution main pipe, decontamination device, fan installation, water pump installation, air duct insulation, water pipe insulation, air duct water pipe support and hanger, etc. Students can contact the reference rooms or bookstores of various design institutes to buy before the design.
(4) Be familiar with the original data of this project.
Graduation design task book is one of the materials provided to students according to the scope and requirements of this design. Together with relevant drawings, it can be used as an imaginary entrusted task for Party A to entrust the design institute with engineering design. Before starting the design, students must be familiar with their own design tasks, including location, orientation, function, nature, grade, operating shifts, building envelope materials, door and window structure levels, room layout, indoor personnel distribution, lighting, air conditioning and refrigeration, ventilation, smoke control and scope, etc. It also includes the types and locations of heat medium, heat source and cold source, and the basic information of Party A (including funds). , and collected air conditioning design data of similar buildings, and absorbed good experience and practices at home and abroad.
(5) collecting outdoor meteorological data
It mainly includes: dry bulb temperature, wet bulb temperature, relative humidity, outdoor wind speed, dominant wind direction, sunshine rate and local air pressure in summer calculated by outdoor air conditioning in winter and summer.
2. According to the task requirements and relevant data, determine the indoor air conditioning design parameters, including indoor temperature and humidity requirements in winter and summer, wind speed, fresh air volume standards, fresh air volume and noise standards.
(1) indoor air conditioning design parameters: National Technical Measures for Civil Building Engineering Design; Code for Design of Heating Ventilation and Air Conditioning (GB 50019-2003); Design Standard for Building Energy Efficiency (GB50 189-2005).
(2) Fresh air volume standard: Code for Design of Heating, Ventilation and Air Conditioning (GB 50019-2003); Design Standard for Building Energy Efficiency (GB 50189-2005); Office 30m3/h people; Shopping malls, bookstores, gyms, restaurants, theaters: 20m3/h people; Classroom 17m3/h people; Recreation hall, ballroom, KTV, beauty and fitness: 30m3/h person; Hotel: Lobby and Four Seasons Hall: 17m3/h people;
5-star: guest room 50 m3/h, dining room 30 m3/h, lobby Four Seasons Hall 65438+100 m3/h;
4-star: guest room 40 m3/h, restaurant and banquet hall 25 m3/h, lobby Four Seasons Hall 65438+100m3/h;
Three-star: guest room 30 m3/h, restaurant and banquet hall 20m3/h;
2-star: guest room 30 m3/h, restaurant and banquet hall:15m3/h.
3. Calculate the cold, heat and humidity loads of each room and the ratio of heat and humidity in winter and summer. The calculation of room cooling load can refer to the textbook "Special issue of air conditioning and load calculation", adopt the simplified calculation method of engineering, or calculate according to the simplified calculation method of air conditioning energy saving in high-rise buildings. The calculation of heat load should be carried out in accordance with the textbook of Heating Engineering, and also refer to the relevant thermal indicators of building area, but the indicators must be used under the guidance of teachers. For the calculation of wet load, please refer to the textbook and the special issue of load calculation. When calculating the cooling and heating load of high-rise buildings, the effects of outdoor wind speed, building height and night radiation on the load must be considered. See Air Conditioning and Energy Saving for High-rise Buildings for details.
4. Determine the air conditioning scheme and air conditioning mode.
(1) Division of air-conditioning system: For high-rise buildings, the load of the plane and vertical rooms in the building is very different, and the purpose, service time and bearing capacity of air-conditioning equipment in each room are different, so the air-conditioning capacity of the whole building is very large. In order to keep the indoor parameters of air conditioning system economical and reasonable, it is necessary to divide the system. System zoning mainly considers indoor design parameters, load characteristics, building height, room use function and time, air conditioning equipment capacity and convenient energy-saving management and other factors. The air conditioning mode should be considered according to the characteristics of different building forms, building use functions, time and air conditioning load.
① Interior design parameters
Generally, rooms with the same or similar requirements for indoor temperature and humidity parameters, cleanliness and noise are classified as one system. For example, hotel rooms and other public rooms (restaurants, dance halls, gyms, conferences, shopping malls, halls, etc.) should consider air conditioning systems separately. ).
② Load characteristics
For large buildings, the surrounding area (the area with a depth of about 4m) is greatly influenced by outdoor air and solar radiation, and the air conditioning load changes greatly in winter and summer. Because the inner zone is far away from the outer envelope, the indoor load is mainly the heat of human body, lighting and equipment, and may be the cold load all year round. Therefore, the plane can be divided into peripheral area and inner area, and the peripheral area can also be divided by direction (when the plane area is large), and air conditioning can be carried out according to the load change characteristics of each area.
③ Building height
In high-rise buildings, the bearing capacity of equipment, pipes, fittings, etc. should be considered. Generally, the water system of buildings below 30 floors is not partitioned, and super high-rise buildings above 30 floors can be vertically divided into 2~3 partitions.
④ Room functions and service hours
According to the purpose, function and service time of each room in the building. For example, office buildings can be equipped with different air conditioning systems according to offices, conference rooms, canteens, halls, etc. Hotel building rooms are used all day, while others, such as restaurants, conference rooms and dance halls, are not used all day, so different air conditioning systems should be set up separately; For hospitals, air conditioning systems should be set in rooms with the same cleanliness requirements.
Please refer to the teaching materials and practical HVAC design manuals or other air conditioning design manuals for the details of air conditioning system division.
(2) the setting position of cold and heat sources
Mainly consider the pressure, maintenance, management, noise, vibration, pipeline length, load on the structure, fuel supply and the impact on the environment and beauty. See the relevant design manual for details.
(3) Selection of cold and heat source equipment
The equipment selection of cold and heat sources must be based on the principle of economy, safety and advanced, and determined through comprehensive technical and economic comparison. The following issues are specifically considered: building use and scale, heat load, refrigerant, equipment characteristics and energy efficiency ratio, power supply, heat source and water source, initial investment and operation cost, maintenance management, location and height of computer room, fire protection, safety and environmental protection requirements.
(1) If the local power supply is tight, there are thermal power stations or enough boilers for heating in winter, especially when waste heat and waste heat (steam above 30kPa or hot water above 80℃) can be utilized, lithium bromide absorption refrigerator should be preferred.
(2) Compared with lithium bromide absorption refrigeration, direct-fired lithium bromide cold and hot water heater has the advantages of high thermal efficiency, low fuel consumption, good safety, direct heating and cooling, initial investment, operating cost and less occupied area, etc. Under the same conditions, direct-fired lithium bromide cold and hot water heater should be preferred.
③ Considering the distribution law of air conditioning cooling load in the whole year and the regulation characteristic coefficient of refrigerator under partial load, the model, number and regulation mode are reasonably selected. Generally, 2 ~ 4 water chillers are selected, including 2 small and medium-sized water chillers, 3 large water chillers and 4 large water chillers. Consider the possibility of standby and inter-unit rotation.
④ According to the energy efficiency ratio, the order of refrigeration equipment is centrifugal-screw-piston-absorption. The energy efficiency ratio of refrigerator is much higher than that of absorption refrigerator. Therefore, when the local power supply is not tight, refrigerators should be the first choice. Selection range of refrigerator: considering the reasonable single machine capacity, when the cooling capacity of air conditioner is less than 582 kW (50 500,000 kcal/hour), piston type should be selected; When the cooling capacity is 582 ~116kw (50 ~110,000 kcal/hour), screw should be selected; When the cooling capacity is > 1 16kW (1 10,000 kcal/hour),
⑤ The selection of heat source equipment should be in line with the national energy policy. On the premise of meeting the technical requirements of fire protection, environmental protection and safety, efficient, clean and environmentally friendly renewable energy sources, such as water (ground) source heat pump, solar energy and nuclear energy, should be selected as far as possible. For non-heating areas, when coal-fired boilers cannot be installed on site, oil-fired and gas-fired boilers can be considered. In principle, try not to use electric boilers.
(4) Equipment layer
For high-rise buildings with less than 20 floors, it is advisable to set the equipment floor at the upper part (such as the roof floor) or the lower part (such as the basement);
For high-rise buildings within 30 floors, two equipment floors should be set up at the upper or lower part;
Super-high-rise buildings with more than 30 floors should be set up with upper, middle and lower floors respectively.
(5) Air conditioning mode
When determining the air conditioning mode, we should consider the nature and use of the building, the use characteristics of the building, the characteristics of air conditioning load, the requirements for temperature and humidity adjustment performance, the initial investment and operation costs, maintenance and management costs, the requirements for the area and location of air-conditioned rooms, and the requirements for air and water pipelines or tube wells. See the relevant manual for details.
(6) Air conditioning water system
Air conditioning water system can be divided into: double control and four control; Closed and open systems; The same program and different programs; Upper score and lower score; Chilled water, cooling water and hot water systems, etc. According to the operation regulation mode, there are constant flow and variable flow systems. Generally speaking, closed mechanical circulation and fractionation system in the same program are widely used in cold and hot water systems. Students can analyze and compare according to the specific situation of the project and the characteristics of various systems.
(7) Fire prevention and smoke exhaust system
As a preliminary consideration, the way, location, location and specific requirements of fire prevention and smoke exhaust should be put forward here.
(8) Air distribution in air-conditioned rooms
5. Determine the air supply temperature difference and each state point on the i-d diagram, calculate the total air supply volume and fresh air volume of each room, and determine the minimum fresh air ratio and return air volume of each system.
(1) Determine the air supply state point and state parameters from the indoor state point, air supply temperature difference and heat-humidity ratio line on the i-d diagram, calculate the cooling load according to the air supply state, indoor state point and each room, and calculate the total air supply of each room.
(2) Determine the fresh air volume of each room according to the fresh air standard and the number of people in each room or the minimum fresh air ratio. Determine the state of the new return air mixing point on the i-d diagram, and obtain the calculated total load of each air conditioning system including the fresh air load.
(3) Calculate the return air volume of each room or system from the total air supply volume, fresh air volume or minimum fresh air ratio.
6. Make the processing flow of each system in winter and summer on the i-d diagram, check whether the air parameters of each room in the same system meet the requirements, and put forward the method and calculation of local terminal treatment. Check indoor state parameters in winter.
7. According to the maximum cooling load in summer, the maximum heating load in winter, the air supply volume of each air conditioning system and the air state parameters, select various air handling equipment, including combined units, variable air volume air conditioners, fresh air units and fan coils.
8. The location and quantity of return air system pipes and return air outlets are preliminarily arranged, and the air conditioning room is arranged.
The layout of the air supply pipeline should be considered together with the layout of the air return port, the location of the machine room and the layout of water pipes. At the same time, the clear height of the ceiling space, the insulation and installation of the air duct, the connection of the air outlet, the turn of the air duct, the position of the tee joint, the valve and accessories of the air duct should be considered. The direction of the air duct must be conducive to air flow and reduce noise, and the connection with the air outlet should be as short and straight as possible.
9. Select and calculate pipeline accessories: control valve, fire damper, static pressure box, muffler, muffler elbow, etc.
10, check and calculate the air distribution in each room, and adjust the position and quantity of air return openings.
1 1. Hydraulic calculation of return air duct system, determination of duct section size and calculation of resistance of each system.
12, air conditioning cold and hot water and cooling water systems are arranged, and hydraulic calculation is carried out to determine the pipe diameter and system resistance of each section.
13. Select and calculate cold water main engine, heat exchange equipment, heat source main engine, cooling tower, distribution main pipe, decontamination device, water filter, pressure reducing valve, steam trap and other equipment and accessories.
14. Arrange the refrigerating machine room, calculate the total resistance of the water system, and select the models and quantities of chilled water pumps and cooling water pumps.
15. Selection of materials and determination of insulation thickness of air ducts, water pipes, equipment and accessories.
16, determine the annual air conditioning system operation adjustment scheme, and put forward energy-saving measures.
17, fire prevention and smoke exhaust design of air conditioning and ventilation system, exhaust system design and others.
18, design and construction instructions
The whole design process should be expressed in the design specification. Design specifications are important materials for engineering design, which have practical value for construction, operation and management, and also have certain reference value for future engineering transformation and similar engineering design. Therefore, the design instructions must be carefully written, the handwriting should be clear and neat, the description should be concise and to the point, and the known data, formulas, results, schemes and main problems involved in the discussion should be recorded for future reference. Be good at using charts to express it, and attach the main reference materials involved to the manual. Provide detailed operation data, economic data and main equipment materials as much as possible.
Construction description: Matters needing attention in construction, such as anticorrosion, insulation, connection mode and pressure test requirements of equipment and materials, which are not clearly indicated in the construction drawing, can be implemented with reference to Practical HVAC Design Manual or other relevant materials. Construction instructions can be written on the drawings.
Third, draw the construction drawing
Construction drawing is an engineering language, which turns design contents into design documents and drawings as the basis for on-site construction. Should be based on the principle of meeting the needs of construction, not only to express the appearance of the project, but also to express the structural details clearly, so we should take it seriously. Before drawing the construction drawing, you should carefully verify the basic design data, understand the construction conditions and material supply, and closely cooperate with other types of work (civil engineering, water and electricity, technology) to make the design conform to the actual situation as far as possible.
1. Drawing contents: See the task book for details.
2. Drawing depth: the position of pipelines and equipment, the relationship between pipelines, etc. It should be clearly expressed and the dimensions are complete (including positioning dimensions, specifications and necessary building dimensions). The names, numbers, elevations and slopes of pipelines, equipment and components shall be clearly expressed. The drawings are required to be clear, with distinct levels and correct fonts. (See drawing standard for heating and ventilation design for details).
Fourth, review and summarize the graduation design, and prepare the graduation design defense.
Combined with the theoretical knowledge learned in the university for four years, this paper summarizes the gains and lessons from the whole process of graduation design, and grasps the method of how to apply the learned knowledge flexibly to the actual engineering design.
Graduation defense is not only a test of students' labor in the process of graduation design, but also a comprehensive test of the professional knowledge they have learned in their four years of university life. On the basis of carefully summarizing the graduation project, students should comprehensively review the professional knowledge and basic knowledge they have learned, calmly and skillfully step onto the defense desk, and hand over an ideal answer sheet to the school teachers and classmates who have worked hard to train you for four years. This is also the last and most important time in your four-year college life.
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