CN108925309B - Self-water supply system for agricultural greenhouse - Google Patents

Abstract

The invention belongs to the technical field of agricultural greenhouses, and particularly discloses an agricultural greenhouse self-water supply system. The system comprises an optical system arranged in a greenhouse, a water making system arranged at one side of the optical system and a blower connected with the water making system; the solar energy limiting and reflecting device comprises an optical system and is characterized in that the optical system comprises a Fresnel lens, a first concave lens arranged at a converging point of the Fresnel lens and sunlight frequency limiting and reflecting glass arranged below the first concave lens, the water preparation system comprises a heat preservation layer, a selective absorption coating and a moisture absorption layer, the moisture absorption layer comprises an absorption material layer and a metal heat conducting rod, and the heat preservation layer can transmit infrared light reflected by the sunlight frequency limiting and reflecting glass. The invention realizes the ladder utilization of sunlight, is clean and environment-friendly, reduces the consumption of non-renewable energy sources, simultaneously realizes the self-watering function of the greenhouse, can provide agricultural water in water-deficient areas, can be used as the supplement of domestic water, and relieves the problem of water shortage.

Description

An agricultural greenhouse self-supply water system

technical field

The invention belongs to the technical field of greenhouse water supply, and more specifically relates to an agricultural greenhouse self-supply water system.

Background technique

With the continuous progress of the society, the traditional agricultural production mode can no longer meet the needs of the development of modern civilization, and the new type of facility agriculture is sought after by people in the industry. The so-called agricultural equipment is actually greenhouse facilities, which are not limited by time and space, and can carry out agricultural production in special environments such as plateaus, deep mountains, and deserts. China is a large agricultural country, where farmers account for more than half of the total population. The space for agricultural innovation and application is infinite, and the agricultural equipment industry has moved from behind the scenes to the front of the stage. Throughout the domestic greenhouse industry, large and small enterprises are uneven, and the quality of the greenhouse projects that have landed is naturally very different.

The inland areas in western my country have arid climate, low annual precipitation, and serious water shortages, making it difficult to realize agricultural planting; the island areas in my country are surrounded by sea, and fresh water purification is difficult and costly, so agricultural water is in short supply.

Chinese patent CN2051204557 U discloses a clean energy system for solar photovoltaic agricultural greenhouses, including a solar photovoltaic power generation system, a ground source heat pump system, a drip irrigation system and plant fill lights, and the electric energy generated by the solar photovoltaic power generation system is supplied to the ground source heat pump System, drip irrigation irrigation system and plant supplementary light. This system combines ground source heat pump technology and drip irrigation and water-saving technology to provide water requirements and temperature conditions for crops in photovoltaic greenhouses. The energy of the entire photovoltaic agricultural greenhouse system comes from solar photovoltaic power. A kind of clean energy, without any pollution to the environment, can ensure the cleanliness of the growing environment of crops, and the excess electric energy can be incorporated into the national grid through grid connection. It is a high-tech ecological system for efficient agriculture. However, this solution does not solve the problems of water shortage and high energy consumption in the existing agricultural greenhouses.

Chinese patent CN107996209 A provides an intelligent environment-friendly planting greenhouse, which is used for planting plants, including a ceiling, side walls, sensors, controllers and operation terminals. The ceiling includes a rainwater collection tank connected to a water storage tank , a flexible thin-film solar module is arranged under the rainwater collection tank, the sensor includes a plurality of sensors, the sensors detect the humidity, light, and temperature in the greenhouse, and the controller obtains test data from a plurality of sensors, and controls the operation according to the test data The terminal solves the problem that the current intelligent environmental protection planting greenhouses are not highly intelligent. This scheme makes full use of natural precipitation resources to improve the production efficiency of greenhouses, but it is not suitable for water-scarce areas such as western my country.

Contents of the invention

In view of the above defects or improvement needs of the prior art, the present invention provides a self-supply water system for agricultural greenhouses, the purpose of which is to use the energy of infrared light in the sunlight as heat energy for dehydration of the adsorption material, and the remaining light is used for the growth of plants, In this way, the step-by-step utilization of sunlight is realized, and at the same time, the self-sufficient water function of the greenhouse is realized, and the problem of water shortage is alleviated.

In order to achieve the above object, the present invention proposes an agricultural greenhouse self-supply water system, which is characterized in that it includes an optical system located in the greenhouse, a water production system located on one side of the optical system, and a water production system connected to the water production system. set blower;

Wherein, the optical system includes a Fresnel lens, a first concave lens arranged at the converging point of the Fresnel lens, and a sunlight frequency-limiting reflective glass arranged below the first concave lens, and the sunlight limit A second concave lens is provided under the frequency-reflecting glass. The Fresnel lens is used to linearly condense sunlight and convert it into parallel light through the first concave lens. The frequency-limiting reflection glass of sunlight is used to Infrared light in the parallel light is reflected onto the water making system;

The water production system includes a thermal insulation layer, a selective absorption coating, and a moisture adsorption layer, and the moisture adsorption layer includes an adsorption material layer and a metal heat conducting rod,

The thermal insulation layer can transmit the infrared light reflected by the sunlight frequency-limited reflective glass, the selective absorptive coating is used to convert the reflected infrared light into heat energy, and one end of the metal heat conducting rod is connected to the selective The absorption coating is connected, one end of which runs through the adsorption material layer, and is used to conduct the thermal energy converted by the selective absorption coating to the adsorption material layer to provide energy for the adsorption material layer to desorb water, and the adsorption The material is used to absorb moisture in the air flowing through it, absorb the heat transferred by the metal heat conducting rod, and desorb the adsorbed moisture at a temperature lower than the boiling point of liquid water to generate liquid water.

Further, there are multiple moisture absorption layers, and the multiple moisture absorption layers are arranged at intervals to form serpentine air passages for air circulation.

Further, one end of the serpentine air passage is connected to the air blower, a water collection tank is provided under the water production system, and a water pipe is provided on one side of the water collection tank.

Further, the water-making unit includes a porous partition, and the porous partition is arranged between the adsorption material and the passage layer, so as to increase the contact area between the adsorption material and the air and to increase the contact area between the adsorption material and the air. outflow of liquid water.

Further, the number of the metal heat conducting rods is multiple, and the metal heat conducting rods pass through multiple water making units and are detachably connected to the multiple water making units.

Further, metal ribs are provided between the selective absorbing coating and the adsorption material and inside the adsorption material, and the metal ribs are fixedly connected to the metal heat conducting rods.

Further, the adsorption material is SiO ₂ ·nH ₂ O ·yCaCl ₂ .

Further, the insulation layer is a vacuum glass layer.

Further, the selective absorbing coating is a thin metal plate coated with a solar selective absorbing material.

Further, the covered central angle of the Fresnel lens does not exceed 150°, preferably, the covered central angle of the Fresnel lens is 120°.

Generally speaking, compared with the prior art, the above technical solution conceived by the present invention mainly has the following technical advantages:

1. In the self-supply water system for agricultural greenhouses of the present invention, during the day, the sunlight is linearly concentrated by Fresnel lenses and concave lenses and then converted into parallel light, and the infrared light is reflected to the water system by using the frequency-limited reflection glass of sunlight. The selective absorbing coating converts infrared light energy into heat energy to provide the energy required for dehydration of the adsorbent material, which is used to absorb moisture in the air flowing through it at night and absorb the heat transferred by the metal heat conducting rod during the day and At a temperature lower than the boiling point of liquid water, the adsorbed water is desorbed to produce liquid water. Through this stepwise utilization of sunlight, the self-sufficient water function of the greenhouse is realized, and agricultural water is provided in water-scarce areas. At the same time, sunlight is limited The second concave lens under the frequency-limited reflective glass converts the parallel light transmitted through the frequency-limited reflective glass into divergent light, providing the crops in the greenhouse with the energy required for growth, and realizing the step-by-step utilization of sunlight.

2. In the agricultural greenhouse self-supply water system of the present invention, a plurality of moisture adsorption layers are arranged at intervals to form a serpentine air passage for air circulation, and the blower sends the ambient air outside the greenhouse into the interior of the adsorption material through the serpentine air passage, further expanding the adsorption capacity. The contact area between the material and the air improves the water absorption efficiency and dehydration rate of the adsorption material.

3. In the agricultural greenhouse self-supply water system of the present invention, the water-making unit includes a porous partition, and the porous partition is arranged between the adsorption material and the passage layer to increase the contact area between the adsorption material and air and the The outflow of liquid water when the adsorbent material desorbs moisture.

4. In the self-supply water system for agricultural greenhouses of the present invention, the number of metal heat conducting rods is multiple and the metal heat conducting rods run through multiple water-making units and are detachably connected with the multiple water-making units to increase the heat conduction of metal. The contact area between the rod and the adsorption material accelerates heat conduction and thus accelerates the desorption speed of the adsorption material.

5. In the self-supply water system for agricultural greenhouses of the present invention, metal ribs are arranged between the selective absorbent coating and the adsorption material and inside the adsorption material, and the metal ribs are fixedly connected to the metal heat conducting rods, In this way, the heat of the metal heat-conducting rod is effectively transferred to the adsorption material evenly and quickly, thereby further accelerating heat conduction and speeding up the desorption speed of the adsorption material.

6. In the agricultural greenhouse self-supply water system of the present invention, the adsorption material is SiO ₂ ·nH ₂ O · yCaCl ₂ , during the adsorption process, part of the water vapor reacts with CaCl ₂ to form a complex, and part of the water vapor is due to intermolecular The active force is adsorbed on the pore wall of porous silica gel, which has the characteristics of fast adsorption speed and large adsorption capacity of the composite adsorbent, which is conducive to taking water from the air. In addition, the material has a lower desorption temperature and can be directly desorbed With the advantages of producing liquid water and more thorough desorption, it is beneficial to turn most of the moisture in the convective air inside and outside the greenhouse into usable liquid water.

7. In the agricultural greenhouse self-supply water system of the present invention, the setting of the glass vacuum insulation layer can reduce the loss of heat conduction and heat convection, and improve the energy conversion efficiency. The other surfaces of the water production unit are provided with insulation materials to reduce the heat between the water production unit and the outside world. loss.

Description of drawings

Fig. 1 is a schematic structural view of an agricultural greenhouse self-supply water system at noon according to an embodiment of the present invention;

Fig. 2 is a structural schematic diagram of an agricultural greenhouse self-supply water system in the morning according to an embodiment of the present invention;

Fig. 3 is a structural schematic diagram of an agricultural greenhouse self-supply water system in the afternoon according to an embodiment of the present invention;

Fig. 4 is a structural sectional schematic diagram of a water production system related to an embodiment of the present invention;

Fig. 5 is a structural schematic diagram of the daytime working state of the water production system involved in the embodiment of the present invention;

Fig. 6 is a structural schematic diagram of the night working state of the water production system involved in the embodiment of the present invention;

Fig. 7 is a flowchart of an agricultural greenhouse self-supply water system according to an embodiment of the present invention.

In all the drawings, the same reference numerals represent the same technical features, specifically: 1-sunlight, 2-optical system, 3-water system, 4-greenhouse body, 5-water pipe, 6-water collection tank, 7-Blower, 201-Fresnel lens, 202-First concave lens, 203-Sunlight frequency limiting reflective glass, 204-Second concave lens, 301-Insulation layer, 302-Selective absorbing coating, 303-Metal fins , 304-adsorption material, 305-porous partition, 306-serpentine air passage, 307-night moist air, 308-openable and closed porous partition, 309-metal heat conducting rod.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

As shown in FIG. 1 , FIG. 2 and FIG. 3 , an agricultural greenhouse self-supply water system of the present invention includes an optical system 2 and a water production system 3 . The optical system 2 is arranged on the inner surface of the cover film of the greenhouse, and the optical system 2 includes a Fresnel lens 201 , a first concave lens 202 , a sunlight frequency-limiting reflective glass 203 , and a second concave lens 204 . The Fresnel lens 201 is installed on the inner surface of the cover film of the greenhouse, and its central angle of coverage does not exceed 150°. Preferably, the central angle of its coverage is 120°, so as to ensure that the system is irradiated to the lens surface within the illumination time (7am～5pm). Sunlight is linearly focused. The concentrated sunlight is used as the main energy source of the present invention. The first concave lens 202 is arranged below the Fresnel lens 201, and the focus of the first concave lens 202 and the Fresnel lens 201 is the same, and the sunlight after converging is converted into Parallel light for subsequent frequency division processing. The parallel light is irradiated to the solar light frequency-limiting reflective glass 203 again, and the near-infrared light with a wavelength between 700nm-2500nm is reflected by the sunlight frequency-limited reflective glass 203 and irradiated to the water-making system 3 located on the side of the optical system as a water-making system 3. Energy source for water system 3. The other visible light in the parallel light passes through the sunlight frequency-limiting reflective glass 203 and then is converted into non-parallel light by the second concave lens 204 to provide a growth light source for the crops in the shed.

As shown in Fig. 4, Fig. 5 and Fig. 6, the water production system involved in the present invention is mainly composed of three layers: a solar energy conversion layer, a moisture adsorption layer and a serpentine air passage. The solar energy conversion layer is mainly used to convert solar energy into thermal energy required for dehydration of the adsorbent material, and it includes a selective absorption coating 302 for absorbing the energy of near-infrared light after frequency-limited reflection to heat up the device. One side of the selective absorbing coating 302 is provided with an adsorption material 304, which is used for absorbing moisture in the air at night and performing dehydration reaction to produce liquid water after being heated at a high temperature during the day. The adsorption material 304 is closely attached to the metal fins 303 , and is used for rapidly transferring the heat energy converted by the selective absorption coating 302 to the adsorption material 304 . The metal heat conducting rod 309 runs through the adsorption material 304 to assist in better transferring the heat energy converted by the selective absorption coating 302 to the adsorption material 304 . The inside of the adsorption material 304 is provided with a serpentine air passage 306, one end of the serpentine air passage 306 is connected to the blower 7, and the other end communicates with the ambient atmosphere outside the greenhouse body 1, and the air blower 7 sends the gas outside the greenhouse body 1 to the serpentine air passage 306 , cooling the adsorption material 304 and providing a water source for the adsorption material 304 . A porous partition 305 is provided between the adsorption material 304 and the serpentine air passage 306. On the one hand, the contact area between the adsorption material 304 and the circulating air in the serpentine air passage 306 is increased; outflow. The lower part of the water production system 3 is provided with a water collection tank 6 for collecting the liquid water produced after the dehydration reaction of the adsorption material 304 . One side of the water collection box 6 is provided with a water pipe 5 for leading the water in the water collection box 6 to irrigate the plants in the greenhouse.

As a preferred solution of this embodiment, an insulating layer 301 is arranged in front of the absorbent coating 302, preferably, the insulating layer 301 is a glass vacuum insulating layer.

As a preferred solution of this embodiment, the selectively absorbing coating is closely attached to the metal fins 303, so that the energy absorbed by the selectively absorbing coating 302 can be quickly transferred to the adsorbing material 304 through the metal fins 303, thereby accelerating the dehydration reaction of the adsorbing material.

As a preferred solution of this embodiment, the water production system 3 is composed of the serpentine air passage 306 and the adsorption material 304. The adsorption materials 304 are placed at intervals. Contact area, improve water absorption efficiency.

As a preferred solution of this embodiment, the selective absorbing coating 302 is a thin metal wall coated with a solar selective absorbing material.

As a preferred solution of this embodiment, the adsorbent material 304 is a composite adsorbent SiO ₂ ·nH ₂ O·yCaCl ₂ . Silica gel is a solid particle with a hard and porous structure. The molecular formula is SiO ₂ ·nH ₂ O. X-ray diffraction proves that it is porous SiO ₂ . The size of the void formed by its skeleton makes silica gel have different specific surface areas, bulk densities, Pore diameter and pore volume. The specific surface area of coarse-porous silica gel is about 580m ² /g. CaCl ₂ and H ₂ O can undergo a reversible chemical reaction to form hydrates (CaCl ₂ ·H ₂ O, CaCl ₂ ·2H ₂ O, CaCl ₂ ·4H ₂ O, CaCl ₂ ·6H ₂ O), and the molecule can adsorb up to 6 _H2O molecule. The specific reaction process is:

CaCl ₂ +H ₂ O=CaCl ₂ ·H ₂ O

CaCl ₂ ·H ₂ O+H ₂ O=CaCl ₂ ·2H ₂ O

CaCl ₂ ·2H ₂ O+2H ₂ O=CaCl ₂ ·4H ₂ O

CaCl ₂ ·4H ₂ O+2H ₂ O=CaCl ₂ ·6H ₂ O

When CaCl ₂ is distributed in the pores of silica gel, water vapor in the air enters the pores of silica gel through diffusion, and the high specific surface area of silica gel increases the contact area between CaCl ₂ and water vapor, which also enhances the interaction between CaCl ₂ and water vapor. reaction. During the adsorption process, a part of water vapor reacts with CaCl ₂ to form a complex, which is chemical adsorption, and a part of water vapor is adsorbed on the pore wall of silica gel due to the force between molecules, which is physical adsorption. The composite adsorbent SiO ₂ ·nH ₂ O·yCaCl ₂ has the characteristics of fast adsorption speed and large adsorption capacity of the composite adsorbent, which is beneficial to air water intake at night.

Hydrates (CaCl ₂ ·H ₂ O, CaCl ₂ ·2H ₂ O, CaCl ₂ ·4H ₂ O, CaCl ₂ ·6H ₂ O) undergo desorption reaction under the condition of 60° to 80°, which is beneficial to the adsorption of moisture during the day Comes out for use in greenhouses.

In Northwest my country, the climate is dry and high temperature in summer. If the adsorption process is carried out at night, the temperature will be lower than the average temperature, and the relative humidity will be higher than the average humidity, which is more conducive to the increase of adsorption capacity and the acceleration of adsorption speed. At the same time, the light intensity is high and the temperature is high during the day, so the desorption reaction takes place during the day, which is beneficial to speed up the desorption reaction of the adsorption material. Therefore, this composite adsorbent also has superior adsorption performance under low humidity and high temperature climate conditions.

As shown in Figure 7, the workflow of the embodiment of the present invention is as follows:

At night, start the blower, the blower sucks the air outside the greenhouse into the water system, the air fully contacts the adsorbent material in the serpentine air passage, cools the adsorbent material, and at the same time the moisture in the air is absorbed by the adsorbent material, and the dehydrated air from Exit discharge. During the daytime, the air blower stops running, and the sunlight is linearly concentrated through the Fresnel lens on the top of the greenhouse and converted into parallel light through the first concave lens and irradiates on the sunlight-limited frequency-limited reflective glass, in which the near-infrared light is reflected by the sunlight-limited frequency The glass is reflected to the water system to provide heat for water production, and the remaining sunlight is transmitted through the frequency-limited reflective glass to the second concave lens and converted into divergent light to provide light for plant growth. The near-infrared light reflected by the solar frequency-limited reflective glass to the water system passes through the glass vacuum insulation layer and is converted into heat on the selective absorption coating. The heat is quickly conducted to the interior of the adsorption material through the metal ribs and metal heat conducting rods. throughout. After the adsorption material is heated, a desorption reaction occurs, and the water adsorbed from the air at night is desorbed to form liquid water. The water flows into the water collection tank through the open and close porous partition at the bottom, and finally the water in the water collection tank is drawn out through the water pipe to irrigate the greenhouse. plant.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (8)

1. The automatic water supply system for the agricultural greenhouse is characterized by comprising an optical system (2) arranged in the greenhouse, a water production system (3) arranged on one side of the optical system (2) and a blower (7) connected with the water production system (3);

the optical system (2) comprises a Fresnel lens (201), a first concave lens (202) arranged at a condensing point of the Fresnel lens (201), and sunlight frequency limiting reflection glass (203) arranged below the first concave lens (202), wherein a second concave lens (204) is arranged below the sunlight frequency limiting reflection glass, the Fresnel lens (201) is used for linearly condensing sunlight and then converting the sunlight into parallel light through the first concave lens (202), and the sunlight frequency limiting reflection glass (203) is used for reflecting infrared light in the parallel light onto the water production system (3);

the water production system (3) comprises a heat preservation layer (301), a selective absorption coating (302) and a moisture absorption layer, wherein the moisture absorption layer comprises an absorption material (304) and a metal heat conduction rod (309),

the heat insulation layer (301) can transmit infrared light reflected by the sunlight frequency-limiting reflection glass (203), the selective absorption coating (302) is used for converting the reflected infrared light into heat energy, one end of the metal heat conduction rod (309) is connected with the selective absorption coating (302), and the other end of the metal heat conduction rod penetrates through the adsorption material (304) and is used for conducting heat energy converted by the selective absorption coating (302) to the adsorption material (304) to provide energy for the adsorption material (304) to desorb water, and the adsorption material (304) is used for adsorbing moisture in air flowing through the adsorption material and absorbing heat transferred by the metal heat conduction rod (309) and desorbing the adsorbed moisture to generate liquid water at a temperature lower than the boiling point of the liquid water;

the plurality of the moisture adsorption layers are arranged between the plurality of the moisture adsorption layers to form a snake-shaped air passage (306) for ventilation; the moisture adsorption layer comprises a porous partition plate (305), wherein the porous partition plate (305) is arranged between the adsorption material (304) and a serpentine air passage (306), so that the contact area of the adsorption material (304) and air is increased, and liquid water flows out when the adsorption material (304) desorbs moisture; the adsorption material is

。

2. The self-water supply system for the agricultural greenhouse according to claim 1, wherein one end of the serpentine air passage (306) is connected with the blower (7), a water collecting tank (6) is arranged below the water preparation system (3), and a water pipe (5) is arranged on one side of the water collecting tank (6).

3. An agricultural greenhouse self-water supply system according to claim 1 or 2, characterized in that the metal heat conducting rod (309) is provided in plurality and the metal heat conducting rod (309) penetrates through and is detachably connected with a plurality of moisture adsorption layers.

4. An agricultural greenhouse self-water supply system according to claim 1 or 2, characterized in that a metal rib plate (303) is arranged between the selective absorption coating (302) and the absorption material (304) and inside the absorption material (304), and the metal rib plate (303) is fixedly connected with the metal heat conducting rod.

5. The self-water supply system for agricultural greenhouses according to claim 1, wherein the heat-insulating layer (301) is a vacuum glass layer.

6. An agricultural greenhouse self-water supply system as claimed in claim 1, wherein the selectively absorptive coating (302) is a sheet metal plated with solar selectively absorptive material.

7. An agricultural greenhouse self-water supply system according to claim 1 or 2, characterized in that the coverage central angle of the fresnel lens (201) does not exceed 150 °.

8. The agricultural greenhouse self-water supply system according to claim 7, characterized in that the coverage central angle of the fresnel lens (201) is 120 °.

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