What are the types of greenhouse cooling methods according to the physical conditions they are used

First, the greenhouse is covered with old shed film.

In summer, many vegetable farmers cover their greenhouses with a year's worth of film to shade the sun. Although this method is simple and convenient, it also has certain drawbacks. First of all, the shading effect is not very good.

Although the light transmittance of the greenhouse film has been reduced for one year, its light transmittance is still relatively high, especially at noon on a continuous sunny day, although the old greenhouse film is covered with a layer of sunlight, the temperature in the shed can still reach 40, and it is difficult to obtain the ideal sunshade and cooling effect. Secondly, sometimes the wind is strong, and it is easy to scrape off the shed film. Third, if a layer of greenhouse film is added, the ventilation of the greenhouse will be hindered, affecting the cooling in the shed.

Therefore, covering the old greenhouse film is only suitable for use when the light is not very strong, and cannot be used as a cooling method for long-term use.

2. Cover the shade net.

Shade netting is all too familiar to vegetable farmers. However, if the choice is not right, or the covering time is too long, the low-light environment will be formed in the shed for a long time, which will not only cause the plant to grow, but also be not conducive to the flowering and fruit setting of vegetables. So how to choose a shade net?

First of all, choose a shade net according to the type of vegetable. At present, the sunshade nets on the market are mainly black and silver-gray. The black shade net has a high shading rate and fast cooling, so it is suitable for short-term coverage in the hot summer when the fields need to be carefully managed. Silver-gray shade netting has low shading rate, which is suitable for light-loving vegetables and long-term mulching.

Tomatoes, for example, are light-loving vegetables, and as long as 11 to 13 hours of light are met, the plant can grow robustly. Although the effect of light time on tomato is not so serious, the light intensity is directly related to the yield and quality, and insufficient light is easy to cause plant malnutrition. Tomatoes have a light saturation point of 70,000 lux and a maximum light intensity of 90,000 lux at noon.

The black shade net has a high shading rate, up to 70%. However, with such a shade net, the light intensity cannot meet the normal growth needs of tomatoes, which is easy to cause tomato growth. So it's best to choose a silver-gray shade net.

Most of the silver-gray shade nets have a shading rate of 40% to 45% and a light transmittance of 45,000 lux, which can meet the normal growth needs of tomatoes.

Secondly, the time period covered should be well grasped. Generally speaking, the shade net should be covered on sunny days and uncovered on cloudy days; Cover at noon, unveil in the morning and evening; Cover in the early stage, and peel off in the late growth stage. If there is a lot of rainy weather and the temperature is not very high, after the vegetables are planted, the shade net can be used only in the 3 5 days of slow seedling period.

If a black shade net is used, cover it only at noon on a sunny day. The shade net is available from 10:30 a.m. to 2 p.m

30。When the shade net is covered, it can not be close to the shed film, otherwise the heat absorbed is easy to be transmitted to the shed through the shed film, and the shade net can not play a good role in reducing the temperature of the shed.

See pages 65-66 of the textbook, humidification, shading, and ventilation.

1.Wet curtain fan system: It mainly uses the evaporation of water to cool down, because the evaporation of water needs to absorb heat, so that it can take away part of the heat in the shed, and at the same time start the negative pressure fan of Yueneng to pump out the hot air flow in the greenhouse, so as to achieve the purpose of cooling.

2.Micro mist system: It is mainly to spray water into the greenhouse in the form of fog particles, so that the fog particles evaporate quickly, can quickly take away the heat in the air, and then discharge the humid air to the outside of the greenhouse to achieve the purpose of rapid cooling.

3.Shading system: It is to block the excess sunlight outside the greenhouse, form shade to protect the crops in the greenhouse, and keep the temperature in the greenhouse at a suitable temperature.

4.Natural ventilation system: one is to remove the waste heat in the greenhouse and reduce the temperature; the second is to eliminate excess water in the greenhouse and reduce humidity; The third is to adjust the air composition content in the greenhouse and increase the carbon dioxide content in the air to increase photosynthesis.

5.White spray on the roof: white reflective effect is the best, forming a white coating on the surface of the greenhouse, which can reflect sunlight well to prevent a large amount of heat energy from entering the greenhouse, and can also convert the sunlight into scattered light that is beneficial to the crop, which is extremely beneficial to the growth of crops.

The greenhouse cooling method can be classified according to the physical conditions it uses, and Shihu can be mainly divided into the following types:

1. Natural ventilation: use airflow to ventilate the greenhouse and reduce the temperature. This method is mainly suitable for areas with dry climate and good ventilation conditions.

2. Forced ventilation: use mechanical equipment (such as electric fans, exhaust fans, etc.) to enhance the airflow to ventilate the greenhouse to achieve the purpose of cooling.

3. Cooling wall: The cooling wall is set inside the greenhouse by using water film or spray system, and the heat is absorbed through the bright evaporation of water, so as to reduce the temperature.

4. Sunshade net: Set up a sunshade net on the roof or side of the greenhouse to block direct sunlight and reduce solar radiation in the greenhouse, thereby reducing the temperature.

5. Cooling agent: spray specific chemicals in the greenhouse to reduce the temperature through endothermic reaction. However, it is important to note that the chemicals used are safe and environmentally friendly.

The implementation of these methods will vary depending on factors such as greenhouse structure, climatic conditions, and crop demand.

When cooling a greenhouse, you need to pay attention to the following:

1. Pay attention to ventilation: keep good ventilation as much as possible, clean up the debris inside and outside the greenhouse in time, and ensure smooth airflow.

2. Control humidity: high humidity will increase the saturation of the air in the greenhouse and affect the heat exchange effect of the airflow in the greenhouse, so it is necessary to pay attention to controlling the humidity of the greenhouse.

3. Reasonable setting of shade nets: choose appropriate shade nets according to local climatic conditions and crop needs, do not over-shield solar radiation, and should be appropriately adjusted when necessary.

4. Precautions for the application of spray coolant: When spraying coolant, attention should be paid to the safety and environmental protection of chemicals, choose products that meet national standards and crop needs, and operate in strict accordance with the instructions for use.

5. Avoid sudden changes: When cooling the greenhouse, attention should be paid to the temperature change not to be too fast and too large, so as not to have an adverse impact on the growth of crops.

In short, greenhouse cooling needs to take effective measures to ensure that the greenhouse environment is suitable for crop growth in combination with local climatic conditions, greenhouse structure and crop demand.

The following are commonly used physical cooling methods, such as attack methods.

a.Apply an ice pack to the cold.

b.Warm bath.

c.Take cold drinks internally.

d.The quilt covers the sweat.

Correct scum brother answer: Ice pack cold compress Yu spine, warm water bath.

Summary. 1.Outstanding features of Shandong shed type: the back wall to the top, thermal insulation and energy storage; Large lighting area; In the case of winter snow and spring rain climate, it is suitable for covering grass curtains and mulching, the groundwater level is deep, and the furrow is planted.

1.Outstanding features of Shandong shed type: the back wall to the top, thermal insulation and energy storage; The area of daylighting is quietly buried; In the case of winter snow and spring rain climate, it is suitable for covering grass curtains and mulching with grass and mulching, with deep groundwater level and planting in furrows.

2.The back wall of the North China Dan bucket shed is called to the top and thickened to keep warm and store energy; The angle of incidence of the sun is low, and the radan of the shed surface and late jujube is increased. In the case of winter snow and spring rain climate, it is suitable for covering grass curtains and mulching, the groundwater level is deep, and the furrow is planted.

3.Outstanding features of the alpine shed: the back wall is thickened to the top and insulated and stored energy; The angle of incidence of the sun is very low, and the arc of the shed surface increases; The shading coefficient is large, and the slag ratio of the front wall is reduced; In winter, there is more snow in the spring, and there is less rain in the Tanliang people, which is suitable for covering the thermal insulation quilt; The rear roof is enlarged to reduce the heat dissipation of the shed; The water table is deep, and the furrow is planted.

3.Outstanding features of the plateau shed: the back wall is thickened to the top, and the insulation allows the reputation to store energy; The angle of incidence of the sun is low, and the arc of the shed surface increases. In winter and spring, the low-temperature snow and little rain are suitable for covering the thermal insulation quilt; The plateau is windy, and the reticulated laminated rope is windproof; The back room is not enlarged on which side to reduce the heat dissipation of the shed surface; The water table is deep, and the furrow is planted.

5.Outstanding features of the extremely cold shed: the back wall is carried to the top and thickened, and the energy is insulated and stored; The angle of incidence of the sun is very low, and the arc of the shed surface increases; The shading coefficient is large, and the front wall is reduced; In winter and spring, there is more snow and less rain, which is suitable for covering thermal insulation quilts; The winter and spring breezes are large, and the mesh laminated rope is windproof.

The rear roof is enlarged to reduce the heat of the scattered ants on the shed surface; The water level is deep and the furrow is planted.

6.The outstanding characteristics of the shed shape of the Central Plains are: the temperature is higher, the groundwater level is shallow, the back wall is to the middle, and the digging depth is reduced; The angle of incidence of the sun is higher, and the greenhouse is widened or lowered; Winter snow and spring rain, suitable for covering straw curtains and mulching; In spring, the wind is strong, and the mesh laminated rope is windproof; The groundwater is shallow and pure, and it is cultivated by ridges.

7.The Jianghuai shed type highlights the characteristics of judging: high temperature, shallow groundwater level, no excavation or shallow excavation in the shed; The angle of incidence of the sun is high, and the shelf widens or decreases in the sky; It is rainy in winter and spring, which is suitable for non-absorbent thermal insulation quilt; In winter, there are many cloudy days and high humidity in the shed, so the dripping dehumidification film is used; The water level is shallow, and the ridge is cultivated.

8.The outstanding characteristics of Jiangnan Feng's shed shape: the groundwater level is shallow, and the shed is not dug in the shed; Vegetables can be grown in all seasons; high land utilization; There is rain and no snow in winter and spring, which is suitable for Yinwanchang non-absorbent thermal insulation quilt; In winter, there is a lot of humidity in the shed on cloudy and foggy days, and a droplet dehumidification film is used; The groundwater table is shallow, and the ridge is cultivated.

9.The outstanding characteristics of the shed shape in South China: the groundwater level is shallow, and the rock foundation in the shed is not dug; Vegetables can be planted in the four seasons; high land utilization; The light is strong, and the astigmatism shed film is used to reduce the light transmittance; The temperature is high, and the top and bottom convection ventilation on both sides are used for cooling; The groundwater table is shallow, and the ridge is cultivated.

Summary. High-temperature greenhouse: Also known as a hot greenhouse. The indoor temperature is generally maintained at 18 30 °C,* for the cultivation of tropical species or for winter purposes.

1.What is a high-temperature greenhouse, an example of a high-temperature greenhouse in flowers-||The application of production.

High-temperature greenhouse: Also known as a hot greenhouse. The indoor temperature is generally maintained at 18 30 °C,* for the cultivation of tropical species or for winter purposes.

The greenhouse is the product of people's struggle with nature and consciously transforming nature; The cultivation of flowers in greenhouses is the result of people's growing demand for flowers. In modern horticultural production, greenhouses have become the basic equipment for the production of vegetables in winter. The characteristic of greenhouse flower cultivation is that its production process is basically carried out under human-controlled environmental conditions, and it is very little affected by changes in natural conditions, especially external meteorological conditions.

The use of greenhouses with good performance and complete supporting facilities can maintain a good microclimate inside the greenhouse and adjust the environmental conditions suitable for flower growth through manual adjustment.

In facility cultivation, the methods of reducing the air temperature in the greenhouse are: shading and cooling, roof water cooling, evaporative cooling and ventilation cooling.

Use ventilation. In general, the greenhouse will be equipped with entrances and exits and a moderate amount of windows, in the hot summer, open the windows and vents, can promote the external air flow inflow, timely replacement of the air in the greenhouse. Ventilation of the greenhouse is a common cooling method in the greenhouse, which is more suitable in the case of low outside temperature, but in the hot summer, ventilation can only let the outside hot temperature pour into the greenhouse, and can not play an effective cooling purpose.

Use shade.

The change of temperature in the greenhouse depends on the irradiation of sunlight to a certain extent, according to this characteristic, the use of shade net to cover the surface of the greenhouse, can play the role of blocking the sun, reduce the exposure time and area of the greenhouse daylight, and can alleviate the problem of excessive temperature in the greenhouse to a certain extent. However, the use of shade nets for a long time will lead to the inability of greenhouse plants to photosynthesize in time, and the lack of sunlight irradiation is harmful to the production of greenhouse plants. Therefore, the use of shade nets can only be used as an emergency and cannot be used as a long-term way to combat the extreme heat.

Use a spray cooling device.

After experimenting with ventilation cooling and shade net cooling methods, we found that the traditional cooling methods could not meet the cooling needs of greenhouses. We urgently need a new method of cooling, a tool to ensure that greenhouses are protected from hot temperatures in the summer.

The use of spray cooling equipment will be the main choice for greenhouse cooling in the future. Spray cooling equipment uses the principle of evaporative cooling, by generating ultra-fine particle water mist, absorbing heat energy in the surrounding area, and evaporating in time, thereby reducing the surrounding temperature, which is an ideal new type of cooling equipment. The application of spray cooling equipment in foreign countries has been very mature, widely used in various industries and fields, it can be used as a cooling equipment for workshops, and can also be used as cooling equipment for outdoor coffee bars and restaurants.

The use of spray cooling equipment has a remarkable effect, not only the cooling effect is good, but also the use cost is small, energy saving and environmental protection, in line with the interests of the majority of greenhouse plants.