What kind of exhaust fan should the hotel install

Hotel industry is developing rapidly, exhaust fan for hotel is whether the air flow is directly related to the hotel can work normally, the reasonable matching system and air purifier is the key to ensure the air purifier purify efficiency, improve customer quality of life, under the together and see what hotels need to install the exhaust fan, exhaust fan which hotel is good?

Based on the practical experience of design, manufacture and installation of hotel air purification equipment, the design and calculation principle of air exhaust system and its matching relation with air purifier are preliminarily studied and discussed.

I. Composition of the hotel's air system

The air system of the hotel is mainly composed of smoke collection hood, air duct, air purifier, air fan (including *) and the overall air supplement device of the hotel

The type and operation mode of the air purifier can be selected according to the actual situation.Prior to the installation of the air purifier, the actual operating parameters of each part of the air system, including operating resistance and exhaust volume, should be calculated.If it is a new project, the design should fully consider the impact on the exhaust system after the installation of air purifier;If it is a renovation project, it is necessary to re-calculate the exhaust system when installing the air purifier. If necessary, it is necessary to transform the smoke collection hood, air pipe and the overall air supplement device of the hotel and replace the air fan.

Ii. Determination of the air exhaust volume of the hotel

In order to ensure the purification effect, the air volume in the actual design shall be strictly calculated according to the intake wind speed of the exhaust hood, which is usually no less than 0.5m/s.The minimum exhaust air volume is usually calculated by the following formula: L=2000PH

Where: L -- exhaust air volume of exhaust hood, m3/h;

P - Perimeter of the cover (excluding the side against the wall), m;

H -- The distance from the hood to the kitchen mouth, M.

After the exhaust air volume is calculated by the above formula, the air suction speed of the hood shall be calculated according to the area of the hood to ensure that the air suction speed of the hood shall not be less than 0.5m/s.

In practical engineering design, the method of estimation is often adopted. According to the regulations on hotel ventilation rate in Technical Measures for HvAC Design of Civil Buildings, hotel ventilation rate can also be determined according to the following ventilation rate:

Chinese hotel: L=40-50 (times /h);

Western restaurant: L=30-40 (times /h);

Staff dining room: L=25-35 (times /h).

Three, air fan

There are three kinds of commonly used air fans: axial flow fan, fan box and centrifugal fan.

1. Axial flow fans used to be widely used, but due to the low total pressure, they are rarely used after the installation of air purifiers.

2, the centrifugal fan full pressure and air volume can be adjusted, but because of the large noise, often need to do noise reduction processing.When the hotel is located at the bottom of the building, its exhaust air should be placed on the roof. On the one hand, it can reduce the indoor noise pollution, and at the same time, the exhaust air duct is in the state of negative pressure, so as to avoid odor overflow.When the fan is placed on the roof, the centrifugal fan is generally chosen.

3, the fan box full pressure is medium, the air volume can be adjusted, and the noise is low, often in the smoke collection hood from the air outlet distance is medium hotel air system to choose.

Four, hotel air conditioning

Due to the structure of the hotel and the different location of the hotel in the building, the hotel should be provided with an orderly air supply by the central air-conditioning system of the building.However, most of the cases we have encountered are buildings without hotel air supply system.Many buildings with restaurants, hotels, etc., are designed with only centralized heating system but no centralized air conditioning system.When the hotel is in a working state, the exhaust system is put into operation, and the hotel is in a state of negative pressure. Fresh air sources include outdoor fresh air penetration and a large amount of air from the restaurant into the hotel.

5. Air duct

The horizontal section of the hotel air duct should not be too long. Generally, the longest horizontal distance should not exceed 15m and there should be a slope of more than 2%. The horizontal end should be equipped with a flexible joint to facilitate cleaning oil and dirt.The exhaust air speed shall not be lower than 10m/s according to the specification, in case the wind speed is too low and the oil is attached to the flue, the branch pipe connected with the exhaust hood shall be equipped with the air flow control valve.

The unreasonable design and installation of air ducts will often cause the hotel air not unobstructed, directly affecting the use of air purifiers.The main reasons are as follows:

1. Due to the air duct passing through the building beam, the ventilation sectional area of the duct becomes smaller, and the resistance on the cross section increases, resulting in the unobstructed airflow.

2, the main air duct ventilation area is not enough, gas flow rate is too large.According to the engineering experience, the wind speed in the air main pipe should not exceed 15m/s.Otherwise, after a period of operation (such as after a year) it is very easy to cause the air system to be blocked.In the operation practice of air purifier, most cases are obstructed due to insufficient ventilation area of air duct, and the flow rate of gas in duct is above 15m/s.

3. The air of hotels on different floors is discharged through the same main pipe. The air effect of hotels on floors near the exit is better, while the air of hotels on lower floors is not unobtainable.

4. When the air duct passes through the building beam or avoids other equipment pipelines, a section of the air duct will be lower than the overall air duct plane.After use for a period of time, the mixture of oil and water will accumulate in the lower part of the air duct, directly affecting the air unobstructed.