Functional equipment in silent ventilation
Silent fan coils
In this category of fan coils, by fully insulating the fan coil and also choosing the right fan and reducing the internal pressure drop, the sound caused by the fan is taken and thus the transmission of the fan sound to the environment is prevented.
VAV coils
This system can be used in environments with less thermal and cooling load and the need to limit the sound of the ventilation system, such as luxury places such as hotels, luxury conference halls and similar places.
The air in this system is supplied by the air generator, which has already been sounded.
Plenum boxes and modern air registers
A ventilation system must produce and distribute a certain volume of air to create favorable air conditions. On the other hand, parameters such as the amount of sound production, air speed and temperature in the room should also be considered. For this purpose, in the design and selection of the air distribution system in each room, the appropriate type of air register, the shape and speed of the air projectile at different temperatures should be calculated and considered in the design in order to create the desired conditions.
Today, different types of modern air registers such as induction, solar and low impulse registers – all equipped with plenum boxes – can be used with very low noise level, about 25-35 db(A), while the air registers that are used in Iran today for Hitting the right projectile often produces a high sound level of around 40-50 db(A).
Plenum boxes
There are different methods for transferring air from the channel to the registers, which can be changed depending on the design conditions and installation restrictions.
One of the prominent systems in this regard is the use of plenum boxes. Today, this system is widely used in modern ventilation due to its special advantages and capabilities.
Advantages of plenum boxes
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Very high volume, especially in low frequencies
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Smoothing the air flow before reaching the valve at low altitude
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The possibility of using a damper to adjust the air
Sound Attenuator box fans
Nowadays, the role of insulated box fans in ventilation systems has become more and more colorful. It is very common to use this type of insulated fans – for example, in home ventilation systems.
Childbeams
The use of strong induction property in the example of active childbeams has caused the complete elimination of the fan compared to the fan coils, which causes the complete elimination of sound.
About 20% of the incoming air in these systems is supplied by the air conditioner, which is already sound-proofed, and the remaining 80% enters the Childbeam from the environment by the induction property (suction) produced by the Childbeam.
Another type of child beam is its Passive type (that is, cooling ceiling panels), which are used to cool the ceiling.
The simultaneous use of radiation properties has a significant effect on the significant increase in the working efficiency of child beams, especially its passive type. In this type of child beam, without the intervention of a fan, the hot air goes up by the natural convection current and after hitting the coil and cooling, it moves down freely without the help of a fan and cools the ambient air.
In each passive and active Childbeam cooling unit, the water temperature between 15 and 17 degrees Celsius is pumped to the Childbeam by the water system in order to bring the ambient air temperature to the appropriate level.
The temperature of hot water in Active Childbeam type is around 50 degrees Celsius, which makes it possible to use solar energy for heating in winter.
Application level of this equipment
In the end, it is important to mention that all the equipment mentioned in this article have been used for many years as complementary components of the ventilation system in developed countries on a large scale. For example, the newest example of this equipment, namely Child Beams, entered the market more than fifteen years ago and today they are widely used in various types of ventilation systems, especially in European countries.
