As one of the main supporting forms of central air-conditioning host products, fan coil units are still widely used as a classic mode of combination with fresh air systems. Due to the advantages of easy installation, small size and low cost, fan coil units are widely used in hotels, office buildings, hospitals, scientific research institutions and other places, but there are many problems with feedback noise during use.

 

At present, there are many domestic engineering units and differences in the strength of design units. Some central air-conditioning systems of smaller projects are directly installed and put into use without being designed by formal design units. The noise of fan coil units in use is directly affected by the selection of units, installation methods, and selected duct materials. The irregularities in air-conditioning system design, air-conditioning installation, and duct material selection have resulted in a variety of fan coil installation forms on the market, which in turn leads to high noise during use, affecting the comfort of use.

 

The following summarizes and analyzes the design and selection of fan coil units, installation methods, and duct material selection.
 

1.Noise problems caused by fan coil unit selection On the one hand, many designers will give a certain amount of air volume margin in the design to ensure sufficient air supply and cooling capacity when designing and selecting fan coil units, or even directly select a larger unit, while ignoring the noise value requirements of the unit itself. It is not until the unit is used that it is found that the noise is too loud, resulting in reduced comfort.

 

On the other hand, in the selection of the static pressure of the air supply unit, a certain amount of duct resistance margin will be given according to the design specifications. Some non-standard designs give too large a static pressure margin. For example, some rooms have small spaces, and only 12Pa is actually enough, but a unit with a static pressure of 30Pa or even 50Pa is selected. According to the characteristics of centrifugal fans, there is a certain conversion relationship between the static pressure and air volume of the unit. 

 

Excessive static pressure directly leads to a large air volume during use, and the noise will also increase, thus affecting comfort.2. Analysis of the impact of installation methods on noise in use. Since there is no more complete guidance document for the installation of fan coil units, and the experience and strength of engineering units are uneven, the installation forms of fan coil units are diverse, and many unreasonable installation methods lead to high noise feedback from users.

 

In places with high noise requirements, it is recommended to add air ducts before and after the unit, and noise reduction measures need to be added to achieve better comfort.

 

3. Analysis of the influence of duct materials on the noise of fan coil units During the use of fan coil units, although the static pressure of the unit is not large and the duct is short, if the selection is improper, it will directly affect the noise of the unit.

 

In the selection of duct materials, in places where noise is required, it is necessary to pay attention not to use ducts made of smooth materials such as ordinary steel plates and aluminum foil inner wall ducts. This material not only has no sound absorption function, but also reflects noise to a certain extent, resulting in greater noise at the air outlet.

 

There are many duct materials with silencing functions on the market. Appropriate materials can be selected according to the place of use to meet the requirements. The current market has made statistics and analysis of commonly used duct materials. It is recommended to use duct materials with silencing functions on the inner wall for places with high noise requirements, which can greatly improve the comfort of use.

 

In summary, in order to improve comfort and avoid unnecessary noise, several aspects need to be considered at the same time. For designers, it is required to go as deep into the site as possible and select the most suitable fan coil unit according to actual needs, including accurate calculation of the required static pressure. In addition, it is also necessary to design a reasonable installation method according to the noise requirements of the place of use.

For the construction party, it is necessary to strictly abide by the construction specifications and select appropriate duct materials.