Seven common ventilation problems in Jiangmen hotel kitchen
Problem 1: in the kitchen ventilation project, the power consumption of smoke exhaust fan and oil fume purification equipment is large, and the function of fan suction is not good Cause: all the exhaust hood pipes of the whole kitchen are finally concentrated in a large system of air pipes, and a large oil fume purification equipment and a large fan are used for exhaust. There is only one stove in the kitchen. The exhaust fan and fume purifier must be on. In this way, not only the exhaust function of the fan is not good, but also the power consumption is very large. In the senior hotels, the power consumption of kitchen ventilation accounts for about 2.8% of the total annual consumption.
Treatment method: dividend two or three systems according to the specific situation, or select variable-speed fan, fully open at peak load. The peak time of kitchen stove operation is about 4-5 hours, while the rest time is processing and preparation or sanitation time, without large exhaust air volume.
Question 2: the air supply system of the hotel kitchen adopts the following ways:
1. Partial return air is used for air treatment;
2. Fan coil is selected;
3. There is no air supply system in the kitchen, but a single cooling fan. Use less than a year on efficiency greatly reduced, so that the kitchen temperature is too high Reason: these equipments have water-cooled surface coolers or direct evaporation surface coolers. The air in the kitchen is directly in contact with the cooler, and the oil mist will soon pollute and block the gap between the fins on the surface cooler, so that the air volume is greatly reduced, resulting in too high temperature and poor function in the kitchen.
Treatment: in the fresh air supply system of the kitchen, return air cannot be used. Only DC system can be used. According to outdoor conditions, DC air conditioning system or DC air supply system can be used. Window type or cabinet type air conditioner should not be used in the kitchen.
Problem 3: the cooling failure of fan coil used in kitchen. The kitchen is equipped with a stove exhaust system, a fresh air compensation system, and a fan coil cooling system. When it was just put into production, the effect was very good. After one year, the temperature could not be reduced, sometimes it was over 35 ℃, which was unbearable for the operators Cause: it is found that the oil mist and water vapor in the kitchen are large, especially the oil fume after gas combustion adheres to the surface of the coil, which greatly reduces the heat transfer coefficient and the cooling effect.
Treatment method: block the fan coil in the return air port of the kitchen, and then use the pipe to guide the air of the dining room as the return air of the fan coil in the kitchen, so as to reduce the amount of outdoor air. (fan coil system cannot be used in kitchen design)
Problem 4: the gas stove fire in the kitchen is sprayed outside the stove door, affecting normal operation Cause: the intake air volume and exhaust air volume share in the kitchen is improper, which makes the negative pressure of the kitchen too high.
Treatment method: for the kitchen with mechanical exhaust system, air intake shall be considered to make up. The negative pressure value of the kitchen shall not be greater than 0.5mm water column. If the negative pressure is too high, the stove will blow back, that is, the flame will spray out. In order to achieve this goal, generally speaking, the supply air volume should be 85% ~ 95% of the exhaust air volume.
Question 5: between the kitchen operation room and the dining room. The kitchen is adjacent to the dining room, which makes people feel uncomfortable and the environment quality of the high-end dining room is not elegant Reason: the air distribution in the kitchen and dining room is not well organized. It should be negative pressure in the kitchen and positive pressure in the dining room. And sometimes because the kitchen has opened the window, causes the kitchen air to flow into the dining room, causes between them everywhere to string the flavor.
Treatment method: to avoid the backflow of kitchen odor, in addition to the transition between the kitchen and the restaurant, 60% of the kitchen exhaust air volume should be supplemented by the restaurant. That is, 60% of the supplementary air volume of the kitchen is sent to the dining room, and then it flows from the dining room to the kitchen. However, it should be noted that the air flow from the dining room to the kitchen shall not exceed 1 m / s when passing through the catering port.
Question 6: the meeting hall of the superior hotel has the taste of cooking in the kitchen Cause: the exhaust outlet of the kitchen is close to the outdoor air inlet of the air conditioner, and the air inlet is set in the downwind direction of the exhaust outlet. As a result, the air intake is not clean, resulting in the smell of the kitchen into the building, resulting in "cross smell".
Treatment method: the fresh air inlet shall be set in the place where the air is relatively clean, and shall be set at the advantageous side of the air outlet, and shall be lower than the air outlet. In civil buildings, try to avoid that the air inlet and the kitchen exhaust are set in the same direction.
Problem 7: the water in the exhaust casing of the kitchen will freeze and affect the use Reason: in cold and cold areas, the exhaust fan of the kitchen is set outdoors. In winter, the water vapor and oil mist in the exhaust will condense and form ice at night. The exhaust fan can not be started in the kitchen operation the next day. Even when the stove is used, not only can not exhaust, but also water drops.
(1) pay attention to the direction of the fan, and try to choose the centrifugal fan with horizontal outlet. If it is necessary to select the upper and outlet fans, a drain pipe shall be installed at the bottom of the fan casing, and the water shall be collected for drainage. The outdoor part of the fan and the air duct shall be insulated.
(2) the horizontal pipeline shall have a slope of more than 2% towards the exhaust hood.
(3) the speed in the exhaust pipe is generally about 10m / s.
(4) the fan should not be set outdoors, but in the exhaust fan room.