The Israeli zigzag greenhouse introduced in Guangxi has a phenomenon of heat accumulation on the top. At noon in summer, the temperature in the heat accumulation zone is nearly 50 °C. The steel frame in this area is hotter, and the film in contact with it ages significantly faster than elsewhere. Natural ventilation has two forms: hot pressure ventilation and wind pressure ventilation. In a hot-pressed greenhouse, the indoor air temperature is always higher than the outdoor air temperature. The air movement always rises indoor air and the outdoor cold air sinks. For example, the roof and side windows have a combined ventilation system with vents, indoor hot air will be discharged through the roof vents, and outdoor cold air enters the greenhouse through the side wall vents.
This system has the largest total ventilation and the best ventilation and cooling performance. Even if there is no wind outside the greenhouse or the wind speed is extremely low, it can guarantee a certain amount of ventilation. The outdoor air movement of the wind pressure and ventilation type forms a negative pressure through the greenhouse roof, thereby driving the air flow and realizing the air exchange inside and outside the greenhouse. If only the roof is ventilated and there is no side wall vent, because the greenhouse is generally tightly sealed, it is not enough to rely on the gap penetration of the greenhouse to supplement the wind pressure. This form often causes the air in the greenhouse to form a negative pressure state, which offsets the roof negative pressure caused by outdoor wind pressure. Even if the outdoor wind speed is higher, the indoor air flow is slow, the total ventilation is greatly reduced, and the ventilation is greatly reduced. The cooling performance is extremely poor, and it is usually necessary to use a forced ventilation system to improve indoor ventilation.
If the greenhouse has only side windows and no roof windows, although the ventilation effect is better than that of only the roof windows, the total ventilation cooling effect is worse than the combined ventilation system due to the roof heating phenomenon and the poor heat and pressure ventilation effect. In addition, attention should be paid to the direction of the side wall vents. In general, the dome-shaped greenhouse has no influence on the wind pressure of the roof in any direction. The main influence is the side wall. Therefore, the ventilation effect of the roof ventilation window side wall windshield in the greenhouse side wall vents greenhouse ventilation system (km/h), the ideal air exchange rate of the air in the greenhouse is 1 time/minute. If you change the temperature by more than 0.75 times per minute, you can take into account the local dominant wind direction when you can control the temperature difference between the inside and outside of the greenhouse within 5 °C.
At present, the greenhouses are mainly ventilated and cooled during the late spring to mid-autumn season. When designing, the side wall vents should be as close as possible to the main wind direction of the above season.
Main processing single crystal furnace, vacuum furnace, furnace, such as sapphire molybdenum, tungsten, tantalum, niobium tungsten bars, tungsten, Tungsten Plate thermal field, tantalum, tantalum plate and other accessories processing, domestic use of the best quality raw materials, equipped with advanced equipment and professional production team, can be customized according to the requirements of all kinds of materials of Tungsten Products, welcome to inquire, looking forward to your cooperation!
tantalum plate price
tantalum plate heat exchanger
tantalum plate supplier
tantalum plate hs code
tantalum plate spec
pure tantalum plate
ion plated tantalum
cost of tantalum plate
tungsten tantalum alloy plate
how much does tantalum cost
tantalum ta73
Tantalum Plate,99.95% Pure Tantalum Plate,Tantalum Ground Ring,High Purity 99.95% Tantalum Plate
Baoji Zhipu Non-Ferrous Metals Processing Co., Ltd. , https://www.czpmow.com