1. The kitchen and equipment shall be set independently, and each shop kitchen shall be set with a set of lampblack exhaust equipment independently. This way can ensure that each kitchen is independent of each other, and eliminate the smell. It is the best way to use lampblack. However, this way requires more tube wells, and takes up a lot of building area and ceiling space. If the business type is adjusted in the later stage, when adding catering stores, additional vertical shafts are needed, which is difficult and costly to transform.
2. The kitchen purification equipment shall be set independently, and the flue shaft shall be discharged in a centralized manner. For several merchants with small area, this form can be used to set up an independent total discharge shaft, and each floor is set with a main oil smoke exhaust pipe. The oil smoke in the merchant kitchen is discharged into the shaft through the main pipe through purification equipment and fans. This method takes up relatively small building area. Due to the need for centralized emission, the horizontal pipe of lampblack exhaust in shops far away from the shaft is long. It is difficult to fully control the air volume and air pressure of the fans installed by each merchant, and it is difficult to control the air volume balance during the operation period. The main air duct of the floor and the shaft are in the positive pressure zone, which has the risk of "smell", affecting the indoor air quality of the entire project.
3. On the basis of the second method, lampblack exhaust shafts shall be set up in different areas, and centralized lampblack exhaust fans and secondary purification equipment shall be set up at the top of the flue shaft to ensure sufficient air volume and air pressure, and reserve allowance for the later increase of catering business. In this way, the vertical shaft and floor air duct can maintain negative pressure under the action of the roof fan, and the risk of "odor" is very small. However, the problem of this way is that the wind volume of the roof fan is large, the power consumption is high, the fan noise is large, and it is difficult to adjust the air volume balance of each merchant, which makes it difficult to measure.
To sum up, Scheme I is recommended when the commercial projects are small, the catering stores are scattered, and the amount of lampblack is not large. Because the amount of lampblack is not large, the primary purification is enough to clean the lampblack, and there is no need to set up independent shafts when the stores are scattered. Scheme III is recommended when the commercial projects are large, the floors are large, and the amount of lampblack from catering is large. Large commercial projects may have a large amount of lampblack in the later period, and the setting of shafts in different regions is convenient for the later period, The secondary purification of the roof ensures the purification efficiency and the negative pressure in the tube well. It ensures that even in the case of air leakage in the air duct, the smell of lampblack will not escape to other areas of the building, so as to ensure the air quality of the building.
2. Determination of air volume of lampblack exhaust system
1. Calculation method The kitchen ventilation shall be determined according to the exhaust air volume of the overall exhaust and the exhaust air volume of the local exhaust of the stove. The overall ventilation volume of the kitchen shall be determined according to the elimination of indoor waste heat and the hot air balance:
The exhaust air volume of the stove shall be calculated according to the following formula:
The total exhaust air volume of the kitchen is the sum of the overall ventilation volume and the stove ventilation volume.
2. Ventilation rate method When there is no condition for calculation in the kitchen at the early stage of design, according to the relevant provisions in the Technical Measures for HVAC Design of Civil Buildings, the air volume of kitchen lampblack can be determined according to the ventilation rate method: 40-60 times/h for Chinese kitchen, 30-40 times/h for Western kitchen, 25-25 times/h for staff dining hall kitchen. At the initial stage of HVAC design, the positioning of catering industry and the planning of catering shop kitchen are uncertain. In the early stage, equipment and reserved pipes are generally selected according to the air exchange rate method. The above air exchange rate is more appropriate for large and medium-sized catering kitchens. However, if the store area is small, the air volume determined by the air exchange rate method has a large error with the actual required air volume. Generally, the minimum air volume is not less than 3000 m3/h.