In order to ensure the purification effect, the exhaust air volume should be calculated strictly according to the suction wind speed of the range hood in actual design. The suction wind speed of the range hood mouth is usually not less than 0.5m/s, and the minimum exhaust air volume is usually calculated according to the following formula: L = 2000 pH
Where: L—— exhaust air volume of exhaust hood, m3/h;
P refers to the perimeter of the hood opening (excluding the wall edge), m;
H refers to the distance from the range hood opening to the kitchen opening, m 。
After calculating the exhaust air volume with the above formula, calculate the suction speed of the hood mouth according to the area of the hood mouth, and ensure that the suction speed of the hood mouth is not less than 0.5 m/s. 。
In practical engineering design, estimation methods are often used. According to the provisions on kitchen ventilation in Technical Measures for HVAC Design of Civil Buildings, kitchen ventilation can also be determined according to the following ventilation times:
Chinese kitchen: L=40-50 (times/hour);
Western kitchen: L=30-40 (times/hour);
Staff canteen: L=25-35 (times/hour).
The term' excluding the wall edge' here means that the wall edge of the exhaust hood forms a closed space with the wall, and there is no air on the side to supplement the exhaust hood, only air in the vertical direction, so it is not necessary to calculate the length of the wall edge in the calculation.