Our daily life, the most contact with the ventilation and air conditioning of the two directions, the northern region and heating and heating. Here we take the direction of air conditioning as an example, talk about the current general process in accordance with how to design.
1 3 stages of HVAC design
A new project, in the domestic design institute, the design will generally have three stages, namely, the program stage, preliminary design stage and construction drawings stage.
1.1 program stage
Program stage, generally building-based, HVAC professional sometimes do not have to do, some large-scale civil or industrial projects, HVAC professional also just do some simple text, say some things to be done in the future, the main means of which technology, etc., basically very simple.
1.2 Preliminary design stage
In the preliminary design stage, HVAC design in addition to the text, but also need to produce some drawings, so that others have a preliminary understanding of the project to be done. For example, take an office building as an example, how do we go to complete the preliminary HVAC design of this project? First of all, to understand the location of the project to be done, nature, grade and other related circumstances, if the building in the north, then we must go to understand the city in winter is the use of centralized heating heating or independent boiler room heating? Is the building a high-grade office building? How does the owner position the building? Do they prefer split air conditioning or centralized air conditioning? Do they use heaters or a centralized central air conditioning system in the winter? Does the building program have requirements for the fa?ade? All these questions need to be considered before doing the design, we need to communicate with the owner, with the relevant government departments to communicate with the relevant design professionals to communicate.
After a lot of information is understood and determined, you can start doing the design. A high-grade office building, if the nature of a single, under 100m, then what design? First of all, there should be a number in mind. Generally speaking, there should be these aspects of the design to be done:
(1) the building's central air-conditioning system. Office buildings generally use fresh air plus fan coil system, and now there are also buildings using VAV all-air system, and the use of centralized floor plus fan air supply, etc., according to the actual situation, to determine the form of a system. Host is the use of air-cooled or water-cooled, is the use of what compression mode of refrigerator, according to the requirements, choose one; water system of how to arrange the director; pumps, refrigerators, how to control the operation and so on.
(2) the building's fire ventilation system. Such a building, a large number of people, need to consider the fire escape, in accordance with the relevant design regulations, consider whether the escape of the closed staircase need to set up pressurized air supply system, fire front room need to set up pressurized air supply system? Is it necessary to set up mechanical smoke exhaust system in the corridor? How to ventilate the restrooms? Is there an underground parking lot in the building, and how to ventilate and exhaust the smoke mechanically? Whether there is a kitchen, how to exhaust fumes? Determine according to the actual situation. After understanding what to do, you can follow the steps below:
1). Calculate the air-conditioning load of the building in winter and summer (at the preliminary design stage, you can use the area index to estimate), calculate the amount of pressurized air supply, calculate the amount of mechanical smoke exhaust, calculate the amount of ventilation in the underground garage and the amount of smoke exhaust for fire fighting, calculate the amount of ventilation in the substation and distribution room, calculate the amount of ventilation in auxiliary rooms, calculate the amount of ventilation in the bathroom, and so on.
2). Layout system, according to the calculation of equipment selection, to the professional information; here the system layout refers to the design of the main system, according to the layout of the system, should be provided to the architectural profession, the location and size of your machine room, the location and size of the pipe wells, through the wall of the big hole location and size, through the floor of the hole location and size, and so on; to the structural profession to provide the weight of the machinery and equipment and the approximate location, through the floor of the hole size and location, and so on. etc. To the electrical professional machinery and equipment power consumption, the main control requirements, etc.; to the water supply and drainage professionals to provide you with the machine's drainage points and water points, etc.. At the same time to accept other professional information provided to you. And according to the summary of each profession, adjust your design plan.
(3) text organization. Out of the refrigeration plant room equipment layout, water system schematic diagram, the main system layout, the main air supply and exhaust plan, fire exhaust plan, machine and equipment schedule, preliminary design instructions and so on. In this way, a complete preliminary design is basically complete, and then after other HVAC designers proofreading, review, validation, and ultimately can be signed out of the map.
1.3 Construction drawings stage
Construction drawings are the basis for the implementation of the project, which is completed on the basis of the preliminary design. Generally speaking, if there are no major changes, basically in accordance with the ideas formed in the preliminary design to deepen the design; if there are changes in the situation, such as the building program for major adjustments, the actual situation and the preliminary design is not the same as the owner's requirements for new changes, then the entire HVAC design needs to be reconsidered. Similarly, let's take that senior office building as an example and continue with its construction drawing design. The content of the required design has not changed, is still the central air-conditioning design, ventilation and fire exhaust design, design and construction instructions and other aspects.
First of all, is the calculation, including air conditioning hot and cold load calculation and ventilation and smoke volume calculation, equipment selection calculation. At this stage, the air-conditioning hot and cold load calculation needs to be in accordance with national requirements, using time-by-time load calculation method, which has a cold load coefficient method and the harmonic method of two kinds, choose one of them can be, the air-conditioning load calculation is very complex and troublesome, there are now a lot of load calculation software, it's more convenient to use; the amount of ventilation and the amount of fire exhaust is based on the relevant regulations issued by the state or design manuals provide Some of the requirements for the calculation; equipment selection calculation is carried out after the system is generally determined, including the selection of fans, end of the air-conditioning equipment selection, pump selection, refrigeration host selection.
Basic parameters and equipment selection, you can carry out the design of the system, and drawing stage. Construction drawings than the preliminary design stage to deepen the depth of the drawings required to get the drawings of the construction unit can be carried out in the actual construction. So what kind of depth is needed? To that office building, the drawings required are: air conditioning and ventilation floor plan, each floor of the fire exhaust and air supply plan, each floor of the air conditioning water plan, freezer room layout, each floor of the air conditioning room samples, air conditioning, ventilation and smoke exhaust air system diagrams, air conditioning system schematic diagrams, water system diagrams, freezer room water system diagrams, freezer room and air conditioning room section, auxiliary equipment node samples, control schematics, design and construction of the general drawing, the design and construction of the building, the construction of the construction drawings. Control schematic diagrams, design and construction of the general description of the equipment and materials list, installation schedule and so on. In these drawings, we want to express the general situation of the project, using what kind of air conditioning system, ventilation system, fire fighting system and control mode, how we arrange the air ducts, water pipe direction, elevation, pipe diameter size, we choose what kind of equipment, how the equipment is discharged, how to link into a system, how the system works, we have to explain how much cooling and heating is needed for each functional room, how much cooling and heating is needed for each functional room, and how much cooling and heating is needed for each functional room. We have to explain how much heat and cold each functional room needs, how much air supply is needed, what kind of heat preservation and anticorrosion materials are used, what kind of vibration isolation and noise reduction forms are used and so on.
In addition to these drawings, we are in the construction, we have to refer to those national and industry standard atlas, to refer to which national design and acceptance criteria, which also need to be accounted for clearly. In doing this work, the same need for the various professions to mention each other's information, which is the same as the preliminary design. After the completion of the entire work, you can drawings, drawings to the owner before the need for internal proofreading, review and validation, some places will have a professional drawing review company for the review of drawings.
2 Summary
The above, just some basic design process and simple methods, in fact, in the design, according to different types of projects, there will be different requirements, there will also be different design methods. These requirements come from our owners, the design of the functional needs of the object, etc.; the design method used, is the theoretical researchers to study the method, our predecessors in the engineering of the specific application of the method, the individual long-term engineering design experience, etc.; we follow the design principle is: saving investment, easy management, advanced technology, energy saving. A good design project, we need to be attentive, holding a rigorous attitude to do, we need to be able to find problems in the construction process and can solve the problem.