Discuss the difficulties and key points in HVAC installation technology?

The following is the relevant content about HVAC installation technology brought to you by Zhongda Consulting for your reference.

1. Introduction

HVAC equipment is a large and complex system project, ranging from large high-rise office buildings and star hotels to small civil buildings. It has an important relationship, and its construction technology is related to key technologies such as pipeline engineering and drawing design. As professional HVAC technicians, we must strictly grasp every construction link to ensure the normal use of the building's HVAC system.

2. Common problems in HVAC installation and construction

(1) Positioning and elevation intersection of pipelines and equipment

For comprehensive buildings There are professional pipelines in the ceiling space such as air conditioning terminal equipment, return air ducts, exhaust ducts, chilled water pipes, condensate water pipes, sprinkler pipes, fire pipes, electrical bridges and other professional pipelines. When construction is carried out according to the drawings when the drawings are insufficiently marked, it is often convenient to construct the pipelines installed first, while the construction of the pipelines installed later is very difficult and can only be installed at locations or elevations that should not be installed, seriously affecting the quality and progress of the project. In response to the above problems, the comprehensive design principles of pipeline engineering must be followed:

(2) Equipment noise exceeding the standard

Equipment noise mainly comes from the collision of air-conditioning terminal equipment, and the main cause of noise is design , installation, especially the noise generated by installation cannot be ignored. In addition to its own major, HVAC also involves various majors such as architecture, vocal music, structure, etc. Noise control requires coordination among various majors.

(3) Water circulation of air-conditioning water system

The water system is the most critical link in the construction of central air-conditioning. Problems in the construction will directly affect the normal operation of the system. The most common problem with central air conditioning chilled water systems is poor circulation in the chilled water system pipes. The reasons for poor circulation of pipelines are: 1. The pipelines intersected by various professional pipelines and were not coordinated during construction, resulting in many air pockets in the pipeline network, affecting the circulation of the pipeline network; 2. The pipelines of the air-conditioning water system were not cleaned cleanly, which directly caused the air-conditioning water The system is clogged.

(4) Water condensation

Condensation and dripping will occur during debugging and operation of the air conditioning system. The reason for this problem may be due to the small slope of the condensate drainage pipe. , or leakage caused by no slope at all. Or the water collection pan of the fan coil unit is not installed levelly, or the drain outlet in the pan is blocked and the pan water overflows. Due to the poor insulation quality of the chilled water pipes and valves, the insulation layer is not close to the wall of the chilled water pipes, causing air condensation to drip from the outer walls of the pipes. There is also secondary condensation water dripping on the lower surface of the water collection pan. Therefore, poor pipeline installation and insulation, loose contact between pipelines and pipe fittings, pipelines and equipment, and illegal operating procedures for pipeline installation may cause this problem. The quality of pipes and key materials directly affects the quality of installation, so it is necessary to conduct a careful inspection of the system before installing pipes.

3. Summary of construction technical difficulties

(1) Treatment of excessive equipment noise

1. Equipment installation

Fresh fans, air conditioners The machine is installed with a spring damping shock absorber, the fan and the air duct are connected by a soft connection, the fresh air unit and the water pipe are connected by a soft joint, the fan coil is connected by a spring hook, and the fan coil and the water pipe are connected by a hose. Perform sound-absorbing treatment on the air-conditioning machine room, such as using sound insulation materials to form an enclosure structure in the air-conditioning machine room to prevent equipment noise from being transmitted outside, or pasting sound-absorbing materials in the machine room: using concave and convex sound-absorbing panels as the wall or ceiling panels of the machine room , to enhance the sound absorption effect: the computer room should minimize the number of doors and windows, and the doors and windows should use sound-absorbing doors and windows or sound-absorbing blinds to minimize the transmission of equipment noise.

2. Water pipe installation

Water pipe installation must strictly comply with national regulations. Chilled water main pipes and cooling water pipe hangers must use spring damping hangers, and the hangers cannot be fixed to the floor. It should be fixed on the beam as much as possible, or channel steel beams should be set up between the beams to fix it. Water pipes must use casings when passing through floors or walls, and fire-retardant materials must be used to seal the space between the casings and water pipes.

3. Wind system installation

The production and installation of air ducts must be carried out in strict accordance with national specifications. Impedance mufflers should be installed at the fan inlet and outlet, muffler louvers should be used at the fresh air inlet, and the air duct should be properly A muffler is installed at the air duct elbow, and a muffler elbow is installed at the elbow of the air duct. The exterior of the air conditioner and fresh air muffler is insulated with high-quality thermal insulation materials. Like the static pressure box, it is covered with high-quality sound-absorbing materials on the inside. Since the reward air ducts adopt low wind speed and large air volume to reduce noise, the cross-sectional area of ??the air duct is relatively large. If the installation strength and overall stiffness of the air duct are insufficient, friction and vibration noise will be generated. It is recommended that the air duct hangers use rubber damping pads as much as possible to ensure that the air duct does not produce vibration noise.

4. Installation of the chilled water pipe main pipe bracket

According to the author's many years of engineering installation experience, it is found that noise will be transmitted along the chilled water main pipe, and as time goes by, it will have an impact on the operation of the equipment. Some damage. After research and testing, the rigid bracket was improved, that is, a spring damper was installed on the original main pipe rigid bracket, so that the vibration and noise were effectively eliminated by the spring damper between the floor slab and the rigid bracket. This technology has been used in several construction projects of a construction company investigated by the author, and has achieved good results. Therefore, it is recommended that the relevant construction companies also use this technology to construct the water supply and return main pipes and chilled water main pipes in the machine room. Eliminate noise.

(2) Methods to solve water cycle faults

1. Pay attention to pipeline quality

Based on the above characteristics of circulating cooling water, the pipeline connection method is required to consider temperature and water pressure. , Corrosion resistance, gap use faults, for example, water circulation faults can be improved by reasonably arranging pipeline slopes and elevations, installing exhaust valves, etc., which has strong operational significance in practical applications.

2. Improve water quality

There are two types of treatment methods for cooling circulating water: physical methods and chemical methods. For the cooling circulating water system, physical methods can be used for water quality treatment and continuous sewage discharge. There are certain standards for controlling the amount of continuous sewage discharge, which is about 0.5-1.0 of the circulating water volume. For newly installed water systems or systems that have been completely descaled, they can also be drained once a week or two weeks. Chemical methods include adding water quality stabilizer method and ion exchange method. The method of adding water quality stabilizers is to add water quality stabilizers with scale inhibition, corrosion inhibition, sterilization, and algae removal functions to the circulating water to treat the circulating water. The water quality stabilizer formula to be added generally requires water quality analysis and is determined through dynamic simulation. At the same time, attention should be paid to its synergistic effects of corrosion inhibition, scale inhibition, sterilization, and algae prevention. If the water quality stabilizer formula is improperly selected, it will cause one thing to be lost. For air conditioning cooling circulating water, this method has high technical requirements, troublesome operation and management, and is rarely used in projects.

(3) Solutions to water condensation

1. When designing pipelines, the length and slope of the pipeline should be appropriate, otherwise dripping will occur. The installation and layout of the pipes should be suitable for draining the condensed water as quickly as possible, and a water sealing device can be installed if necessary.

2. Pay attention to the thermal insulation of materials. The air ducts and chilled water pipes must be insulated. There are two aspects to the insulation of the pipes. One is to ensure their integrity, and the other is their airtightness. The integrity of the pipe insulation requires that cold damage is not allowed. Once there is cold damage on the surface, insulation materials should be laid and insulated. The airtightness of the thermal insulation is required to ensure that no damage is allowed on the thermal insulation layer, and the seal must be ensured to be airtight.

(4) Strengthen the cooperation among various professions

During the installation process of central air conditioning, it involves the cooperation between multiple professions, which is often caused by the lack of good communication between the professions. Many inconveniences may even affect the construction period. There are mainly the following problems:

1. Requirements for civil engineering technology

(1) The size of holes reserved for ventilation ducts in concrete walls, floors, etc. is not provided to Civil engineering majors and implemented in civil engineering drawings, resulting in holes being dug during construction, increasing unnecessary expenses, and even affecting the strength of the building structure, especially the lifting holes for large equipment, ventilation ducts, pressure measuring pipes and other pre-installed equipment in civil air defense projects. If the pre-embedding work of leaving holes is not done well, it will be difficult to deal with.

(2) There are no specific construction requirements for air ducts in civil construction.

For example, when laying bricks in a ventilation shaft, cement mortar should be used to ensure that the inner wall of the air duct is smooth and does not leak.

(3) There is no requirement for drainage in the computer room. As a result, there is no drainage facility in the computer room. The refrigeration machine room should be equipped with drainage ditches and a nearby sump. A drainage pump with a water level controller should be installed in the sump. In particular, there are many equipment in the basement, and the chillers, filters, etc. must be flushed regularly. If the system runs out of water and there is no drainage facility in the machine room, equipment flooding will occur.

2. Coordination between equipment majors and civil engineering majors

The traditional way of laying pipes is to hang them under the beams. When there are many pipes, the floor height must be increased. But in fact these pipes are relatively concentrated, so it is obviously uneconomical to raise the entire floor. If during the structural design, metal casings are pre-embedded in the beams so that some not too large pipes can be laid through the beams, it will not only effectively utilize the space but also eliminate the need for brackets and hangers, and the structure will be completely bearable. In addition, some casings should be embedded in the beams and slabs above the walkways and door openings for emergency needs. For complex buildings, due to the long construction period, it is inevitable to modify or add pipes. It is much more proactive if there are spare reserved holes. The structure can be strengthened from the reinforcement by leaving casings in the beams. However, it is illegal to drill holes in the beams. Civil construction is a big no-no.

IV. Conclusion

In the process of installation and construction of HVAC projects, in addition to the above problems, new problems will continue to arise, and managers and technical personnel will continue to accumulate problems during the construction process. With experience and continuous improvement of professional skills, I believe that the level of HVAC technology will become higher and higher in the future.

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