In kitchen ventilation engineering, smoke exhaust fans and oil fume purification equipment consume a large amount of power, and the effect of fan ventilation is not good. Reason: All exhaust hood pipes in the overall kitchen are finally concentrated in a large air duct system, where a large oil fume purification device and a large fan are used for ventilation. As a result, as long as there is a kitchen stove to use, the exhaust fan and oil fume purifier must be turned on. As a result, not only the exhaust effect of the fan is not good, but also the power consumption is high. In high-end hotels, the annual electricity consumption for kitchen ventilation accounts for about 2.8% of the total annual consumption.
Solution: According to specific circumstances, it can be divided into two or three systems, or variable speed fans can be used to fully open during peak load. The peak time for kitchen stoves to be used is approximately 4-5 hours, while the rest of the time is processing and preparation or hygiene time, requiring no large exhaust air volume.
Question 2: The air supply system for the hotel kitchen adopts the following methods:
1. The air treatment method uses partial return air;
2. Fan coil unit is adopted;
3. The kitchen is not equipped with an air supply system, but with a single air cooler. The efficiency is greatly reduced after less than a year of use, making the kitchen temperature too high. Cause: These devices themselves have water cooled surface coolers or direct evaporative surface coolers. The air in the kitchen is directly in contact with the cooler, and the oil mist will soon contaminate and clog the gap between the fins on the surface cooler, greatly reducing its air volume, causing the temperature in the kitchen to be too high and the effect to be poor.
Solution: In the fresh air supply system of the kitchen, return air cannot be used. Only DC type systems can be used. Depending on outdoor conditions, either a DC air conditioning system or a DC air supply system can be used. Window or cabinet type air conditioners are not suitable for use in kitchens.
Problem 3: Kitchen fan coil cooling failed. The kitchen is equipped with a stove exhaust system, a fresh air supplement system, and a fan coil cooling system. When it was first put into production, the effect was very good. After a year, the temperature could not drop, sometimes reaching over 35 ℃, which was unbearable for the staff. Cause: Upon inspection, it was found that the oil mist and water vapor in the kitchen were both large, especially the oil fume after gas combustion adhered to the surface of the coil, which greatly reduced its heat transfer coefficient and worsened the cooling effect.
Solution: Plug the fan coil at the return air port in the kitchen, and then use pipes to guide the air from the dining room as the return air for the kitchen fan coil, while reducing the amount of outdoor air delivered. (Fan coil system cannot be used in kitchen design)
Problem 4: The kitchen gas stove fires outside the kitchen door, affecting normal use. Cause: Improper ratio of air intake and exhaust in the kitchen, resulting in excessively high negative pressure in the kitchen.
Solution: For kitchens equipped with mechanical exhaust systems, supplementary air intake should be considered. The negative pressure value of the kitchen shall not be greater than 0.5mm water column. Excessive negative pressure in the stove will cause a downdraft, which means that the inflammation vaccine will spray outward. To achieve this goal, the air supply volume should generally be 85% to 95% of the exhaust air volume.
Question 5: Interrogation between the kitchen operation room and the dining room. The kitchen is adjacent to the restaurant, creating an uncomfortable feeling, making the environmental quality of the high-end restaurant not fragrant and elegant enough. Reason: The airflow in the kitchen and restaurant is not well organized, which should be due to negative pressure in the kitchen and positive pressure in the restaurant. Sometimes, due to the opening of windows in the kitchen, the air from the kitchen flows into the dining room, resulting in a cross flavor between the two.
Solution: To prevent kitchen odor from pouring back, in addition to setting up a walkway transition between the kitchen and the dining room, 60% of the kitchen exhaust air volume needs to be supplemented by the dining room. That is, 60% of the supplementary air volume in the kitchen is sent to the dining room, and then flows from the dining room to the kitchen. However, it should be noted that the wind speed when the airflow flows from the dining room into the kitchen and passes through the catering opening should not exceed 1m/s.
Question 6: The conference hall of a high-end hotel smells like cooking in the kitchen. Reason: The exhaust outlet of the kitchen is relatively close to the outdoor air inlet of the air conditioner, and the air inlet is located in the downwind direction of the exhaust outlet. As a result, the intake air is not clean, leading to the introduction of kitchen odor into the building, resulting in a "cross flavor".
Solution: The fresh air inlet should be located in a place with relatively clean air, and should be located on the windward side of the exhaust outlet, and should be lower than the exhaust outlet. Try to avoid setting the air inlet in the same direction as the kitchen exhaust in civil buildings.
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