1. The purpose of central air conditioning design.
1. Gain a preliminary understanding of the entire process of building air conditioning system design, and become familiar with the steps of air conditioning and refrigeration design as well as modern engineering design methods.
2. Engage in in-depth basic engineering training related to the major, and initially receive training and edification in large-scale engineering design.
3. Integrate and deepen technical basic courses and specialized course knowledge, and cultivate the ability to analyze and solve problems.
4. Cultivate a spirit of collaboration and foster a strong sense of responsibility towards work.
II. Content of the central air conditioning course design.
Based on the architectural plans, sectional drawings, and written materials provided by the architecture discipline, we will gain a detailed understanding of the room usage functions and characteristics, and then proceed with the design of the air conditioning and refrigeration engineering for the building.
1. Preliminary design content: The preliminary design of air conditioning and refrigeration engineering should include the following content.
(1) Determine the type of air conditioning system to be adopted and proceed with the division of the air conditioning system.
Determine whether to adopt an all-air system, an all-water system, or an air-water system, whether to use the same system for all areas or different systems for each area, and define the scope of each system.
(2) Determine indoor and outdoor design parameters.
Determine outdoor design parameters based on existing manuals and specifications.
Determine the interior design parameters based on manuals and specifications. If the manuals and specifications do not provide detailed and specific regulations, it is necessary to draw on the experience of existing projects or existing research results, and conduct a careful analysis based on the specific situation of the design object to determine the parameters. If necessary, research and demonstration of interior design standards should be carried out.
(3) To calculate the summer air conditioning load, one can utilize the cooling load coefficient or frequency response method, or employ cooling load calculation software for the computation.
(4) Determination of air supply volume and air supply state parameters, and verification calculation of airflow distribution.
Determine the air supply volume and air supply state based on the load, and determine the air supply method, including the form and layout of air outlets, air supply speed, and air supply temperature difference. Verify whether the air supply method meets the design requirements for airflow distribution.
(5) Selection of air treatment scheme.
For all-air systems, determine whether to adopt primary return air or secondary return air; for air-water systems, determine the process of air treatment; determine the state of mixed air and dew point; determine which feasible air treatment method to adopt to achieve the required air supply state.
(6) Selection (design) and verification calculation of air handling equipment.
Based on the previous calculations, determine the specifications, models, quantities, operating parameters, cold and hot state parameters, etc. of air handling equipment (coolers, heaters, spray chambers, humidifiers, air filters, fan coils, etc.).
(7) Layout and design calculation of air ducts, as well as selection or verification of fans.
The layout and design calculation of air ducts require determining the direction of the ducts, as well as the length and diameter of each section of pipe. The assumed velocity method or static pressure recovery method can be used to determine the type, specification, quantity, and position of various components of the air ducts, such as air valves, tees, elbows, and fire dampers. Calculate the total resistance of the most unfavorable loop. Determine the insulation materials for the pipes.
When selecting or verifying a fan, it is necessary to determine the model, specifications, and design operating point of both the fan and the motor.
(8) Determine the overall plan for the cold source.
Determine whether to use natural or artificial cold sources; compression or absorption; piston, centrifugal, or screw type. Determine the total cooling capacity.
(9) Select the cold source unit.
Determine the type, specifications, and quantity of the refrigeration equipment.
(10) Select a cooling tower and design a cooling water system.
Determine the form, layout, and operation mode of the cooling water system. Perform design calculations for cooling water pipelines; select cooling water pumps and motors. Determine the insulation allowance for pipelines.
(11) Design calculation of chilled water system.
Determine the form, zoning, layout, and operation mode of the chilled water system. Perform design calculations for the chilled water piping; calculate the chilled water pumps and motors. Determine the insulation materials for the piping.
(12) Refrigeration system design.
The design of a refrigeration system encompasses the selection of refrigerant; determination of the refrigeration method; calculation of the refrigeration system cycle and its thermodynamic properties; design and selection of compressors, evaporators, and condensers; selection of throttling mechanisms and auxiliary equipment; and piping design for the refrigeration system.
After the preliminary design is completed, a design specification should be prepared.
2. Construction drawings and their contents.
The construction design drawings include floor plans, sectional views, axonometric drawings, schematic diagrams, enlarged views of machine rooms, detailed drawings, etc. The specific contents of various drawings are described below.
(1) Plan of the air conditioning system.
Draw the positions of air conditioning system pipes, reducers, elbows, inspection ports, air valves, fire dampers, air supply outlets, and exhaust outlets using double lines.
Mark the dimensions of air ducts and air inlets, the radius of curvature of elbows, the positioning dimensions and outline dimensions of equipment, the main dimensions of equipment foundations, system numbers, airflow directions, the names, specifications, and models of equipment components, the location and model of mufflers, the referenced standard drawings, general drawing indexes, or tables.
The fan coil system includes a water system. The air handling part of the fan coil system has the same requirements as the ventilation system.
(2) Sectional drawing of ventilation and air conditioning system.
Draw the positions of pipelines, equipment, and components corresponding to the plan, as well as the positions of relevant process equipment, using double lines; indicate the pipe diameter or cross-sectional dimensions, and elevation. Show and indicate the types, sizes, elevations, and air flow directions of air inlets and outlets; equipment center elevations; heights of air ducts exiting the roof, air cap elevations, and cable fixing, etc.
(3) Plan and sectional view of the air conditioning room.
According to the requirements of standard drawings or product samples, the combination segment code and form of the selected air conditioner, as well as the spraying level, nozzle aperture, and the type, model, and quantity of fans, motors, air filters, heaters, and surface coolers will be determined.
Draw the locations of return air ducts, fresh air ducts, water supply and drainage pipelines, as well as cold and heat medium (water, refrigerant, steam) pipelines, various valves, hoses, silencers, vibration isolators, and louvers.
Mark the pipe diameters, cross-sectional dimensions, and positioning dimensions of pipelines and various equipment for each section.
Prepare a list of equipment and main components.
(4) Plan and sectional view of the cold source room.
The floor plan and sectional drawing of the cold source machine room should be drawn and marked with the location, outline, and basic dimensions of the cold source equipment.
Draw the routing of cold and heat medium circulation pipelines, cooling water pipelines, and the location of drainage ditches, as well as various valves on the pipelines, using single lines.
Mark the dimensions from the center of the equipment to the wall or axis; mark the pipe diameter and vertical position dimensions.
Mark the equipment center, foundation surface, pool, water surface line, overflow port, and pipe elevation.
Prepare a list of equipment and main components.
(5) Axonometric drawing of ventilation and air conditioning system.
When the design content of the air conditioning and refrigeration system is only clearly indicated on a plan, a 45° axonometric projection is required to draw this diagram.
Mark the positions of air inlets, air valves, air caps, and various irregular-shaped components; indicate the diameter (cross-sectional size), elevation, slope, slope direction of the air duct, air volume of each air supply and exhaust inlet, model and elevation of the air cap.
(6) Isometric drawing of the air conditioning water system.
The isometric drawing of the air conditioning water system is drawn using single-line 45° axonometric projection. Valves and other components are represented by legends, with pipe diameters, slopes, slope directions, and elevations indicated.
Outline the relevant equipment such as heaters and coolers with thin lines, indicating the connections between the equipment and the pipelines.
(7) The schematic diagrams that need to be drawn during the schematic and construction drawing design phase include schematic diagrams for air conditioning water systems, air systems, and refrigeration systems.
Post time: Jan-06-2026