Application Of Constant Air Volume Valve In Ventilation And Air Conditioning System

Application Of Constant Air Volume Valve In Ventilation And Air Conditioning SystemSep 22,2021

(1) Application In Fresh Air System

At present, in China, fan coil plus fresh air system of air conditioning is more common, especially hotel rooms, office buildings are used in this way. The general practice is to set fresh air unit on each floor, the corridor laid fresh air dry pipe, dozens of branches from the main pipe into each room. Take hotel rooms as an example, each room fresh air volume is generally 100m3/h, how to achieve the same air volume of each branch? Generally the designer willadd an air flow control valve on the fresh air branch, expect to complete the air flow distribution by means of later debugging. Because the fresh air system is generally long in main pipe and short in branch pipe, the adjustment of air volume control valve is neither intuitive nor ideal, moreover, the fresh air volume of each room is only 100m3/h, and the air volume is very small such debugging is almost impossible to accomplish. The construction unit can only measure the total air supply quantity of the fresh air dry pipe to ensure that the air supply branch pipe has air feeling. In order to ensure that the room can be delivered to the design value of fresh air, and do not need construction units to another room a room of the balance, we only need to add each branch in the fresh air volume valve, the above problems will be solved.

People who live and work in high-rise buildings often worry about the lack of fresh air, and designers often feel aggrieved. Because from the drawing, the value of fresh air volume standard is not low, but we often ignore a problem, how to ensure the actual effect from the design point of view, and the application of constant air volume valve in fresh air system is a powerful measure.

Because the current air valve is mainly dependent on imports, the price is more expensive, I suggest in four or five-star hotels, high-grade office use is more appropriate.

(2) Application In The Ventilation System

A good air conditioning system design, its exhaust system must be very reasonable, and this point is often ignored. In civil buildings, especially in high-rise buildings, the air-tightness of the envelope is very good, only less air flow can maintain the positive pressure of the room. About 85 ~ 90% of fresh air volume must be through the organized exhaust air out of the room, so as to ensure supply air, exhaust air volume balance, otherwise no amount of fresh air can be sent into the room. In civil building, exhaust air is discharged from the outside through the auxiliary room such as toilet, boiled water room. In addition, sometimes should also add a set of exhaust air system, can guarantee supply, exhaust air balance. For the toilet ventilation, the usual practice is to each toilet with one or two toilet ventilator, ventilation shaft with the Exhaust Fan interlock. We know that the fresh air system in high-rise buildings should be running all year round, the corresponding ventilation system should also be running all year round. That is to say, the person that uses toilet can not control the opening of toilet ventilator, the necessity that sets toilet ventilator did not have. Moreover, a large fan with dozens of small fans such exhaust system operation is difficult to match, and not economical. The volume of exhaust air is 400m3/h the noise of the toilet ventilator has 40dB or so, make the toilet lose tranquility. A large number of bathroom ventilators also bring great trouble to maintenance. To solve this problem, we can cancel the toilet ventilator, add a constant air volume valve on each layer branch pipe of the exhaust shaft, and set a exhaust fan on the top of the shaft. Such a ventilation system, can ensure that each layer of air roughly equal, and the system control is simple, reliable operation, the toilet can be very quiet.

(3) Application In VAV Air Conditioning System

In variable air volume air conditioning system, the variable air volume is used in the outer area and constant air volume is used in the inner area.

(4) Application In Clean Air Conditioning System

It is very important to maintain the positive pressure of cleanroom in the clean air conditioning system. The positive pressure of cleanroom can be effectively ensured by setting the air volume valve in the air exhaust system or the air supply and exhaust system.

The clean operating room needs to keep positive pressure when the operation is carrie and when the operation is not carried out. When the operation is carried out, the amount of fresh air needed to ensure the positive pressure and the amount of fresh air needed by the staff are needed When the operation is not carried out, the fresh air volume is only required to ensure the positive pressure, so a double-position wind volume valve is needed on the fresh air duct.

(5) The Application In The Air Duct Line Balance

In the whole air system, because of the influence of the construction conditions, the resistance between branches is not balanced, usually using three-way control valve or open multi-leaf control valve to complete the air distribution. In order to ensure that the air volume in the important room or the main branch pipe is not too large or too small, and to reduce the blindness of debugging, the air volume valve can be appropriately set to replace the three-way control valve or open multi-leaf control valve.

(6) The Characteristics Of The Use Of Constant Air Volume

Constant air valve is an automatic mechanism, without external power, can add electric actuator through remote control signal to change the flow setting. The constant air valve can be used in the air supply and exhaust system, the working temperature is 10 ~ 50 °C, the pressure difference range is 50 ~ 1000PA, that is, at least 50Pa after the front valve, otherwise the constant air valve can not work. This should be noted, because the fresh air system fresh air unit wind pressure value is generally not large. Fixed air valve installation is not limited by the position, but the valve shaft should ensure the level, the general requirements of the valve length 1.5 times the distance of the straight-line inlet duct and 0.5 times the distance of the straight-line outlet duct. The control precision of the constant air valve is high, the external pointer shows the flow scale, the adjustment precision is about 4% , the current-limiting mechanism does not need to maintain, in order to match with the system, the constant air valve rectangular, circular, heat preservation, noise elimination type can be selected.

Just as the balance valve is more and more adopted by the designers in the air conditioning water system, the constant air volume valve will be widely used in the air supply and exhaust system because of its accurate adjustable and automatic balance characteristics.