Agricultural cooling greenhouse based on radiation refrigeration film
By using radiative cooling films in greenhouses, heat is radiated to the outside using materials with high reflectivity and infrared emissivity, solving the problems of low cooling efficiency and environmental unfriendliness in summer high temperatures, and achieving zero-energy cooling and a suitable environment for crop growth.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DONGGUAN UNIV OF TECH
- Filing Date
- 2025-04-29
- Publication Date
- 2026-05-19
AI Technical Summary
Existing greenhouses suffer from low cooling efficiency, high costs, and environmental problems due to their reliance on energy-intensive equipment or inefficient shading measures in high-temperature summer environments.
By using a radiation cooling film, heat inside the greenhouse is radiated to the outside space through materials with high reflectivity and high infrared emissivity. Combined with light-transmitting protective panels and different layout designs, passive cooling is achieved.
It achieves zero-energy, high-efficiency cooling, maintains a suitable growing environment for crops, and reduces the energy consumption and environmental impact of traditional methods.
Smart Images
Figure CN224250306U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of agricultural planting technology, and in particular to an agricultural cooling greenhouse based on a radiation cooling film. Background Technology
[0002] With the continuous advancement of science and technology, the integration of "technology + agriculture" has become a research hotspot. China boasts a vast total greenhouse area, reaching approximately 1.8553 million hectares as of 2023, making greenhouse cultivation a crucial component of agriculture. As a semi-enclosed facility, greenhouses can regulate environmental factors such as temperature, humidity, and light intensity, providing a suitable environment for crop growth. This significantly improves crop yield, quality, and the stability and efficiency of agricultural production, bringing substantial economic and social benefits to farmers.
[0003] Traditional greenhouses face numerous challenges in the high temperatures of summer, especially in terms of cooling. In Central and Southern China, average summer temperatures typically exceed 30°C, while greenhouse temperatures often soar above 50°C. This high temperature environment negatively impacts crop growth, leading to poor root development and premature or delayed fruiting. It also causes a range of diseases, such as sunscald, leaf curl, and powdery mildew. High temperatures affect not only the yield and quality of grain crops but also reduce the production of other cash crops, decreasing farmers' income. Therefore, addressing the issue of high temperatures in greenhouses during summer remains crucial for improving agricultural productivity.
[0004] Currently, the main methods for solving the problem of high temperatures inside greenhouses include the following:
[0005] The first and most common cooling method involves laying shade netting flat on the top of the greenhouse. Shade netting is typically made of black plastic, which farmers lay flat on the greenhouse roof. Due to its dark color, the shade netting absorbs most wavelengths of light entering the greenhouse, reducing the heating effect of sunlight and providing insulation. The advantage of shade netting lies in its low price due to its plastic nature, allowing for effective cooling while reducing costs. However, its disadvantages are also significant: First, the shading rate is low, failing to completely block sunlight and potentially failing to effectively lower the temperature inside the greenhouse; second, shade netting is usually made of plastic (such as polyethylene PE, polypropylene PP, etc.) or fiber materials (such as polyester fiber), making it susceptible to damage from wind, rain, and other natural factors, resulting in a relatively short lifespan; finally, as a plastic product, shade netting is difficult to degrade in the natural environment, potentially causing environmental damage.
[0006] The second cooling method is ventilation based on temperature changes inside the greenhouse. Ventilation involves farmers opening the greenhouse film or pre-designed vents to allow airflow between the greenhouse and the outside, achieving cooling and air removal. However, this method requires farmers to have a clear understanding of crop growth and ventilate at the appropriate time; otherwise, excessive ventilation can cause excessive water loss from the plant surface, leading to adverse effects. Therefore, many farmers now combine automated devices and temperature sensors to achieve intelligent ventilation and lower the greenhouse temperature. The principle of ventilation is to maintain a relatively uniform temperature inside and outside the greenhouse through convection. In summer, when the outside temperature is also very high, the cooling effect of ventilation is very limited; in this case, ventilation mainly serves to release carbon dioxide and control humidity.
[0007] The last commonly used method is to use electrical equipment for cooling, such as agricultural air conditioners and evaporative cooling fans. For large-scale greenhouse cultivation, using large-scale equipment is a more effective method. Agricultural air conditioners are mainly used for high-end cash crops that require high temperature conditions and low-temperature cultivation. Compared to agricultural air conditioners, evaporative cooling fans are more common and are chosen by most large-scale greenhouse industries. Both methods lower the temperature inside the greenhouse by consuming electricity to power the compressor. In general, electrical equipment has significant advantages. For temperature control, electrical equipment is far more precise than the previous two methods, enabling real-time control of temperature changes. Secondly, for crops with high low-temperature requirements, electrical equipment can create a low-temperature environment by consuming a large amount of energy, basically meeting the crop's growth conditions. However, electrical equipment is generally more expensive, consumes more electricity, and causes serious carbon emissions, making it environmentally unfriendly.
[0008] Therefore, existing greenhouses need to be improved to address the problems of low cooling efficiency, high cost, and environmental unfriendliness caused by their reliance on energy-intensive equipment or inefficient shading measures in high-temperature summer environments.
[0009] The information disclosed in this background section is included only to enhance the understanding of the context of this disclosure, and therefore may contain information that does not constitute prior art known to those skilled in the art. Utility Model Content
[0010] One objective of this invention is to provide an agricultural cooling greenhouse based on a radiation cooling film, which can effectively solve the problems of low cooling efficiency, high cost, and environmental unfriendliness caused by existing greenhouses relying on high-energy-consuming equipment or inefficient shading measures in high-temperature summer environments.
[0011] To achieve the above objectives, this utility model provides an agricultural cooling greenhouse based on a radiation cooling film, comprising:
[0012] Greenhouse frame;
[0013] A light-transmitting greenhouse film, comprising a top greenhouse film fixed to the top surface of the greenhouse frame and side greenhouse films fixed to the circumferential surface of the greenhouse frame; wherein the top greenhouse film and the side greenhouse films enclose and form a planting space;
[0014] A radiative cooling film is fixed to the top surface of the top greenhouse film and is used to radiate heat outward from the planting space to reduce the temperature inside the planting space.
[0015] A light-transmitting protective plate is located on the top surface of the radiation-cooling film.
[0016] Optionally, the top canopy film includes several reflective areas and several exposed light-transmitting areas;
[0017] Only the reflective areas of the film are provided with the radiation cooling film and the light-transmitting protective plate.
[0018] Optionally, the top canopy film includes two inclined top surfaces arranged in a pointed structure, and each of the film-coated reflective areas and each of the exposed light-transmitting areas are arranged at intervals along the length direction of the inclined top surfaces.
[0019] Optionally, the top canopy film has an arc-shaped structure that arches upwards from the center.
[0020] Optionally, the reflective areas of the film and the exposed light-transmitting areas are arranged at intervals along the length of the top film.
[0021] Optionally, the reflective areas of the film and the exposed light-transmitting areas are arranged at intervals around the axis of the top film.
[0022] Optionally, the reflective areas of each of the film and the exposed light-transmitting areas are arranged in an alternating pattern of black and white squares on a chessboard.
[0023] Optionally, all the reflective areas of the film are clustered on one side, and all the exposed light-transmitting areas are clustered on the other side.
[0024] Optionally, the top canopy film is a continuous sloping structure that slopes downwards from one end to the other.
[0025] The beneficial effects of this utility model are as follows: It provides an agricultural cooling greenhouse based on a radiation cooling film, and the cooling process is as follows:
[0026] (1) Sunlight exposure stage:
[0027] Sunlight passes through the light-transmitting protective panel (which protects the radiative cooling film from damage caused by wind, rain, dust, etc., and extends its service life) and the radiative cooling film, with some of it being reflected (reducing heat absorption) and the rest entering the greenhouse.
[0028] The high reflectivity of the radiative cooling film prevents the greenhouse roof from heating up due to heat absorption.
[0029] (2) Heat radiation stage:
[0030] Heat inside the greenhouse is conducted to the radiant cooling film at the top through the light-transmitting greenhouse film;
[0031] The radiative cooling film dissipates heat directly into the external space through infrared radiation (without requiring continuous electrical input), achieving passive cooling.
[0032] (3) Temperature control effect:
[0033] The radiant cooling film continuously radiates heat outward from the greenhouse, maintaining the temperature within a suitable range for crop growth even in high summer temperatures.
[0034] Therefore, the agricultural cooling greenhouse based on radiation cooling film provided by this utility model can effectively solve the problems of low cooling efficiency, high cost and environmental unfriendliness caused by existing greenhouses relying on high-energy-consuming equipment or inefficient shading measures in high-temperature summer environments. Attached Figure Description
[0035] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0036] Figure 1 A schematic diagram of the structure of an agricultural cooling greenhouse based on a radiation cooling film provided for an embodiment;
[0037] Figure 2 A schematic diagram of an agricultural cooling greenhouse with a horizontally striped pointed roof provided for an embodiment;
[0038] Figure 3 A schematic diagram of an agricultural cooling greenhouse with a horizontally striped arc-shaped roof provided for an embodiment;
[0039] Figure 4 A schematic diagram of an agricultural cooling greenhouse with a vertically striped arc-shaped roof provided for an embodiment;
[0040] Figure 5 A schematic diagram of a checkerboard-shaped arc-shaped agricultural cooling greenhouse provided for an embodiment;
[0041] Figure 6 A schematic diagram of an agricultural cooling greenhouse with a single-sided film covering provided for an embodiment;
[0042] Figure 7 A schematic diagram of a sloping-roof agricultural cooling greenhouse provided for an embodiment;
[0043] Figure 8 The temperature variation graph is shown for experiments with different coverage rates of horizontal striped gable roofs.
[0044] Figure 9 The graph shows the changes in light and humidity during experiments with different coverage rates of horizontal striped gable roofs.
[0045] Figure 10 A graph showing temperature changes under different coverage rates of a horizontally striped arched roof in hot weather.
[0046] Figure 11 This is a graph showing the changes in light and humidity under different coverage rates of a horizontally striped arched canopy during hot weather.
[0047] Figure 12 This is a graph showing the temperature changes under normal weather conditions with different coverage rates of a horizontally striped arched roof.
[0048] Figure 13 This is a graph showing the changes in light and humidity under different coverage rates of a horizontally striped arched canopy in normal weather conditions.
[0049] Figure 14 This graph shows the temperature changes under different coverage rates of a horizontally striped arched roof during rainy weather.
[0050] Figure 15 The graph shows the changes in light and humidity under different coverage rates of a horizontal striped arched roof during rainy weather.
[0051] Figure 16 A graph showing the changes in plant height of Chinese cabbage under different coverage rates of a horizontally striped arched canopy from November 9th to 31st;
[0052] Figure 17 A graph showing the changes in lettuce plant height from November 9th to 31st during an experiment with different coverage rates under a horizontally striped arched canopy.
[0053] Figure 18 A graph showing the changes in cabbage plant height from November 9th to 31st during an experiment with different coverage rates under a horizontally striped arched canopy.
[0054] Figure 19 The graph shows the changes in plant height of Chinese kale from November 9th to 31st during an experiment with different coverage rates under a horizontally striped arched canopy.
[0055] In the picture:
[0056] 1. Greenhouse frame;
[0057] 2. Translucent greenhouse film; 201. Top greenhouse film; 2011. Exposed light-transmitting area; 202. Side greenhouse film;
[0058] 3. Radiative cooling film;
[0059] 4. Translucent panel guard. Detailed Implementation
[0060] In this utility model, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of this utility model. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this utility model, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.
[0061] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit the invention.
[0062] In the description of this utility model, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " generally indicates that the preceding and following objects have an "or" logical relationship.
[0063] In this invention, terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy, or order between these entities or operations.
[0064] Without further limitations, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this invention is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a series of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.
[0065] Similar to the understanding in the Examination Guidelines, in this utility model, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments of this utility model, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.
[0066] In the description of the embodiments of this utility model, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the convenience of describing the specific embodiments of this utility model or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this utility model.
[0067] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this utility model, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this utility model pertains, the specific meaning of the above terms in the embodiments of this utility model can be understood according to the specific circumstances.
[0068] This invention provides an agricultural cooling greenhouse based on a radiation cooling film, aiming to solve the problems of low cooling efficiency, high cost, and environmental unfriendliness caused by existing greenhouses relying on high-energy-consuming equipment or inefficient shading measures in high-temperature summer environments.
[0069] Example 1
[0070] See Figure 1 This embodiment provides an agricultural cooling greenhouse based on a radiation cooling film 3, comprising:
[0071] Greenhouse frame 1;
[0072] The light-transmitting greenhouse film 2 includes a top greenhouse film 201 fixed to the top surface of the greenhouse frame 1 and a side greenhouse film 202 fixed to the circumferential surface of the greenhouse frame 1; wherein the top greenhouse film 201 and the side greenhouse film 202 enclose and form a planting space.
[0073] A radiative cooling film 3 is fixed to the top surface of the top greenhouse film 201 and is used to radiate heat from the planting space to reduce the temperature inside the planting space.
[0074] The light-transmitting plate 4 is located on the top surface of the radiation cooling film 3.
[0075] It should be noted that the radiation cooling film 3 is a functional material with high solar reflectivity (>90%) and high infrared emissivity (8–13 μm band). It can directly dissipate heat to the outside space through the principle of passive radiation cooling, achieving energy-free cooling.
[0076] Optionally, the light-transmitting panel 4 is made of 1mm thick acrylic sheet (glass, quartz, PC sheet, PET sheet, etc. can also be used), the radiant cooling film 3 is 0.15mm thick, and the light-transmitting greenhouse film 2 is a 0.1mm thick traditional greenhouse film (PE film, PVC film, etc.). The greenhouse frame 1 is generally made of galvanized steel pipe, aluminum alloy, bamboo and wood, fiberglass FRP, etc.
[0077] The cooling process of the agricultural greenhouse based on the radiation cooling film 3 is as follows:
[0078] (1) Sunlight exposure stage:
[0079] Sunlight passes through the light-transmitting panel 4 (which protects the radiative cooling film 3 from damage caused by wind, rain, dust, etc., and extends its service life) and the radiative cooling film 3, with some of it being reflected (reducing heat absorption) and the rest entering the greenhouse.
[0080] The high reflectivity of the radiative cooling film 3 prevents the greenhouse roof from heating up due to heat absorption.
[0081] (2) Heat radiation stage:
[0082] Heat inside the greenhouse is conducted to the radiant cooling film 3 at the top through the light-transmitting greenhouse film 2;
[0083] The radiation cooling film 3 dissipates heat directly into the outside space through infrared radiation (without the need for continuous electrical input), thus achieving passive cooling.
[0084] (3) Temperature control effect:
[0085] The radiant cooling film 3 continuously radiates heat outward from the greenhouse, keeping the temperature inside within a suitable range for crop growth even in high-temperature summer conditions.
[0086] Therefore, the agricultural cooling greenhouse based on the radiative cooling film 3 provided by this utility model can effectively solve the problems of low cooling efficiency, high cost and environmental unfriendliness caused by existing greenhouses relying on high-energy-consuming equipment or inefficient shading measures in the high-temperature environment of summer.
[0087] See Figure 2 In this embodiment, the top film 201 includes several reflective areas and several exposed light-transmitting areas 2011; only each reflective area is provided with the radiation cooling film 3 and the light-transmitting protective plate 4.
[0088] Crops in the planting space still need direct sunlight to grow. The exposed and light-transmitting area in 2011 is designed so that sunlight can directly shine on the crops so that they can carry out photosynthesis normally.
[0089] By alternating between reflective areas and exposed light-transmitting areas 2011, the radiative cooling film 3 reflects sunlight (reducing heat absorption) while allowing some areas to pass directly through, ensuring the light intensity required for crop photosynthesis. This design balances cooling and light requirements, avoiding the drawbacks of traditional shade nets that completely block sunlight.
[0090] Optionally, the top film 201 includes two inclined top surfaces arranged in a pointed structure, and each of the film-coated reflective areas and each of the exposed light-transmitting areas 2011 are arranged at intervals along the length direction of the inclined top surfaces.
[0091] The sloping top surface with its pointed structure optimizes the angle of sunlight incidence. The film-coated area and the exposed area are arranged alternately along the slope to enhance airflow (hot air rises along the slope and dissipates through the radiative cooling film 3), while improving rainwater drainage efficiency and reducing damage to the membrane material from accumulated water.
[0092] Or see Figure 3 The top film 201 has an arc-shaped structure that arches upwards from the center. The arc-shaped structure (such as an arch) increases the internal space of the greenhouse and improves the problem of hot air accumulation. The arc-shaped top surface covered by the radiant cooling film 3 can radiate heat to the atmospheric window (8–13 μm band) more efficiently, and the arc-shaped design disperses stress and extends the service life of the film.
[0093] Optionally, the reflective areas of the film and the exposed light-transmitting areas 2011 are arranged at intervals along the length of the top greenhouse film 201. This arrangement of the film and light-transmitting areas at intervals along the length is suitable for long, narrow planting layouts (such as ridge planting), allowing for flexible adjustment of the area width according to the crop row spacing, achieving precise localized cooling without affecting overall light uniformity.
[0094] Or see Figure 4 The reflective areas of the film and the exposed light-transmitting areas 2011 are arranged at intervals around the axis of the top greenhouse film 201. This arrangement around the axis forms alternating annular areas, suitable for circular or centralized greenhouses, ensuring uniform light exposure for crops in all directions, while also ensuring uniform heat dissipation within the area covered by the radiant cooling film 3, avoiding localized high-temperature dead zones.
[0095] Or see Figure 5 The reflective areas of the film and the exposed light-transmitting areas 2011 are arranged in a checkerboard pattern of black and white squares. This checkerboard pattern further optimizes the distribution of light and heat. The combination of dense reflection from the film-covered areas and uniform illumination from the light-transmitting areas is suitable for light-sensitive crops (such as leafy vegetables). Experiments have shown that this design can increase yield by 1–3 times.
[0096] Or see Figure 6 In some other embodiments, all the film-coated reflective areas are clustered on one side, and all the exposed light-transmitting areas 2011 are clustered on the other side. This separation of the film-coated and light-transmitting areas is suitable for north-south oriented greenhouses: the film-coated areas are concentrated on the west side to block strong afternoon sunlight, while the light-transmitting areas receive gentle morning sunlight on the east side, reducing the risk of crop sunburn.
[0097] Or see Figure 7 In some other embodiments, the top canopy 201 can also be a continuous sloping structure that slopes downwards from one end to the other. This continuous sloping structure, combined with the unidirectional radiative cooling film 3, is suitable for installation against a wall. The sloping surface guides hot air flow towards the end covered by the cooling film, enhancing the passive cooling effect, while the sloping light-transmitting area allows for adjustment of the incident light angle.
[0098] Understandably, the various roof structures mentioned above, through optimized spatial arrangement, have solved the problems of high energy consumption, excessive shading, or uneven cooling in traditional cooling methods. Combined with the zero-energy characteristics of the radiative cooling film 3, they have achieved a synergistic improvement in cooling efficiency and crop growth.
[0099] In summary, the agricultural cooling greenhouse based on the radiative cooling film 3 provided in this embodiment has the following advantages:
[0100] (1) Zero-energy high-efficiency cooling
[0101] By utilizing the high solar reflectivity (>90%) and high infrared emissivity (8-13μm band) of the radiation cooling film 3, heat inside the greenhouse is passively radiated to the outside, achieving cooling without additional energy consumption.
[0102] (2) Photothermal synergistic regulation
[0103] The alternating arrangement of reflective and transparent areas in the 2011 film design both reflects some sunlight to reduce heat absorption and retains transparent areas to ensure the light required for crop photosynthesis.
[0104] (3) Structural optimization for heat dissipation
[0105] The pointed or curved top design optimizes the hot air flow path, and combined with the radiative cooling film 3, it improves heat dissipation efficiency while improving the spatial distribution and stress bearing capacity inside the shed.
[0106] (4) Strong environmental adaptability
[0107] The light-transmitting panel 4 is covered with a radiation cooling film 3, which is rainproof, dustproof and extends service life; different arrangement patterns (such as checkerboard pattern, side-gathering) are suitable for various planting scenarios.
[0108] (5) Flexible layout design
[0109] The film and light-transmitting areas can be arranged at equal intervals, such as on a slant or around an axis, to achieve precise local cooling and light adjustment, avoiding the problems of excessive shading or uneven cooling in traditional shading.
[0110] Example 2
[0111] This embodiment describes the radiation cooling film.
[0112] Radiation cooling film is a functional material with high solar reflectivity (>90%) and high infrared emissivity (8–13 μm band). It can directly dissipate heat to the outside space through the principle of passive radiation cooling, achieving energy-free cooling.
[0113] The structure of a radiation-cooling film mainly includes a flexible polymer layer, a reflective layer, and a radiating layer. The cooling principle relies on the high transmittance of the reflective layer (typically a highly reflective metal such as Ag or Al) and the radiating layer (an optical metasurface array structure) in the mid-infrared atmospheric window band. Since all heat radiation on Earth is primarily emitted into outer space via the infrared band, and the temperature in outer space is absolute zero, the system can continuously radiate heat into outer space, lowering the temperature of the planting space under the film and maintaining a lower temperature inside the greenhouse compared to the ambient temperature. Based on its radiation power density per unit area (P, determined by the properties of the radiation-cooling film itself and weather conditions, with an average radiation power of 100W / ㎡), the total cooling power is controlled by its surface area (S) using the formula: E = P × S.
[0114] To design more efficient radiant cooling and shading products, it is necessary to understand the heat preservation and cooling process. During this process, under the condition that the vehicle body has a certain thermal insulation performance, the temperature T inside the greenhouse is the most important parameter for evaluating non-electric radiant cooling and shading products.
[0115] (1)
[0116] The heat absorbed by light and heat conducted is Q1, the heat radiated by heat conducted is Q2, the heat radiated by the film to outer space is Q3 (Q is positive when the temperature rises and negative when the temperature falls), the specific heat capacity inside the greenhouse is c, for example, air (c=1.004kJ / (kg·K) (under standard air conditions)), and m is the mass.
[0117] Equation (1) shows that when the heat radiated from the film to outer space is greater than the heat absorbed by the greenhouse system, the temperature inside the greenhouse can be reduced. Therefore, the following methods can be used to improve the cooling performance of this design:
[0118] 1) Reduce heat absorption, including reducing light absorption (such as increasing the film coverage to reduce light transmittance) and internal and external heat conduction (such as improving the greenhouse's airtightness and controlling ventilation time).
[0119] 2) Increasing radiant heat: Under clear, windless conditions, the radiative efficiency of the thin film is high; increasing the film coverage can also improve cooling efficiency.
[0120] Specifically, the specific structure and principle of the radiation cooling film are existing technologies, and companies such as Ningbo Ruiling New Energy Technology Co., Ltd., China Construction Southwest Institute Photonics Technology Co., Ltd., Blue Era, and Moguang New Energy Technology (Suzhou) Co., Ltd. have produced and applied it. This utility model will not elaborate on the specific structure and working principle of the radiation cooling film.
[0121] Example 3
[0122] This embodiment will use specific experimental data to illustrate the actual effect of the agricultural cooling greenhouse based on radiation cooling film provided in the embodiment.
[0123] Application Example 1: Testing a horizontally striped gable ceiling (e.g.) Figure 2 (As shown) Cooling effect
[0124] On December 17, 2023, an experiment was conducted in Dongguan City, Guangdong Province. The equipment used was the Pony.ai SNSR-XMZN-ZNB environmental monitoring instrument, which includes a temperature sensor (instrument error ±0.3℃), a humidity sensor (instrument error ±3%), and a light intensity sensor (instrument error ±7Lux). Four greenhouses with pointed roofs were set up, spaced 1 meter apart. All greenhouses were covered with a PE film base. Greenhouse A served as the control group and received no treatment; Greenhouse B was covered with a 25% coverage radiative cooling film in a horizontal stripe pattern; Greenhouse C was covered with a 50% coverage radiative cooling film; and Greenhouse D was covered with a 75% coverage radiative cooling film. All radiative cooling films were laid in a horizontal stripe pattern. The monitoring instrument was positioned in the center of each greenhouse and recorded environmental changes throughout the day, recording every 30 minutes. Temperature changes were as follows: Figure 8 As shown, humidity and light changes are as follows Figure 9 As shown.
[0125] Depend on Figure 8 It can be seen that, firstly, the temperatures in the four greenhouses (A, B, C, and D) were similar at night. During the day, the temperatures in all four greenhouses rose significantly, reaching their maximum values at noon. Greenhouse A had the highest temperature, reaching 16.2℃; Greenhouse B was 0.2-0.4℃ lower than Greenhouse A, indicating a less significant cooling effect. This is because the weather in December was relatively cold, and the day of the experiment was cloudy (e.g., Figure 9 As shown in the figure, the film coverage is small, resulting in an insignificant cooling effect of the radiant cooling film. The temperature of greenhouses C and D is 1-1.5℃ lower than that of greenhouse A, with a maximum temperature difference of 1.5℃. Among the three groups of agricultural cooling greenhouses based on radiant cooling film, greenhouses C and D have the most significant cooling effect at noon, while greenhouse D has the best cooling effect after noon.
[0126] This demonstrates that agricultural greenhouses based on radiative cooling films still maintain a certain cooling effect even in low-temperature and overcast conditions. Compared to traditional agricultural films under the same conditions, they exhibit the ability to regulate the plant growth environment. This indicates the feasibility of applying radiative cooling films in traditional greenhouses.
[0127] Application Example 2: Testing an agricultural cooling greenhouse with an arc-shaped roof based on a radiative cooling film (e.g., Figure 3 (As shown) Cooling effects and plant growth under different weather conditions
[0128] From October 26th to November 31st, 2024, an experiment was conducted in Dongguan City, Guangdong Province. The equipment used was the Pony.ai SNSR-XMZN-ZNB environmental monitoring instrument, which includes a temperature sensor (instrument error ±0.3℃), a humidity sensor (instrument error ±3%), and a light intensity sensor (instrument error ±7Lux). Three arched-roof greenhouses were set up, spaced 1m apart, all with a PE film base. Greenhouse A served as the control group, receiving no treatment; Greenhouse B was covered with a 50% coverage radiative cooling film laid in a horizontal stripe pattern; Greenhouse C was covered with a 75% coverage radiative cooling film laid in a horizontal stripe pattern. All three groups had the same number of planting pots, planted with the same number of Chinese cabbage, lettuce, bok choy, and Chinese kale. The monitoring instrument was positioned in the center of the greenhouse, recording environmental changes daily, every 30 minutes, and crop height daily. Temperature changes during hot weather were recorded as follows: Figure 10 As shown; changes in air humidity and sunlight during hot weather are as follows: Figure 11 As shown. Temperature changes during normal weather are as follows: Figure 12 As shown; changes in air humidity and sunlight during ordinary weather are as follows: Figure 13 As shown. Temperature changes during rainy weather are as follows. Figure 14 As shown; changes in humidity and sunlight during cloudy and rainy weather are as follows: Figure 15 As shown in the figure. The changes in the height of the Chinese cabbage plants from November 9th to November 31st are as follows. Figure 16 As shown; the changes in the height of Chinese cabbage plants from November 9th to November 31st are as follows. Figure 16 As shown; the changes in lettuce plant height from November 9th to November 31st are as follows. Figure 17 As shown; the changes in cabbage plant height from November 9th to November 31st are as follows. Figure 18 As shown; the changes in Chinese kale plant height from November 9th to November 31st are as follows. Figure 19 As shown;
[0129] from Figure 10 , Figure 12 , Figure 14It can be seen that during the early morning and nighttime hours, the temperatures in the three greenhouses were not significantly different, with the agricultural cooling greenhouse based on the radiant cooling film being 0.1℃ lower than the ordinary greenhouse. Around noon, the ambient temperature rose rapidly, and the temperatures in the three greenhouses also gradually increased. At this point, a significant temperature difference became apparent between the three greenhouses, with greenhouse A having the highest temperature, 50% coverage being in the middle, and 75% coverage having the lowest temperature. In the afternoon, as sunlight decreased, the temperatures all tended to decrease until they stabilized. The cooling effect of agricultural greenhouses based on radiative cooling films varies under different weather conditions. Taking the cooling effect at noon as an example: In hot weather, the highest temperature in greenhouse A is 48℃, greenhouse B is 14.4℃ lower than greenhouse A, and greenhouse C is 21.4℃ lower than greenhouse A. In normal weather, the highest temperature in greenhouse A is 43.9℃, greenhouse B is 4.7℃ lower than greenhouse A, and greenhouse C is 9.9℃ lower than greenhouse A. In cloudy or rainy weather, the highest temperature in greenhouse A is 31.1℃, greenhouse B is 2℃ lower than greenhouse A, and greenhouse C is 3.3℃ lower than greenhouse A. Therefore, agricultural greenhouses based on radiative cooling films have the most significant cooling effect in sunny and hot weather. In cloudy or rainy weather, due to cloud cover and low atmospheric transmittance, the cooling effect is sharply reduced. Furthermore, the cooling effect becomes more significant as the coverage of the radiative cooling film increases.
[0130] Depend on Figures 16-19 It can be seen that after 23 days of growth, at the end of the experiment on November 31, for different coverage rates, the crops grown in ordinary greenhouses grew slowly, and their plant height was also lower than that of the 50% coverage group and the 75% coverage group. However, as the coverage rate of the radiant cooling film increased, the plant height increased, and the growth was similar. This is because all four crops belong to the Brassicaceae family, and the suitable growing temperature is 15℃-25℃. Therefore, under the condition of ensuring light, the higher the coverage rate, the better the crop growth. For different varieties of plants, there are slight differences in growth. First, for Chinese cabbage (such as...) Figure 16 Greenhouse B is 3.4cm taller than greenhouse A, greenhouse C is 3.87cm taller than greenhouse A, and greenhouse C is 0.47cm taller than greenhouse B. Secondly, for lettuce (such as...) Figure 17 Greenhouse B is 1.56cm taller than greenhouse A, greenhouse C is 2.76cm taller than greenhouse A, and greenhouse C is 1.2cm taller than greenhouse B; furthermore, for cabbage (such as...) Figure 18 Greenhouse B is 1.05cm taller than Greenhouse A, Greenhouse C is 1.94cm taller than Greenhouse A, and Greenhouse C is 0.89cm taller than Greenhouse B; finally, for Chinese kale (such as...) Figure 19 Greenhouse B is 3.83 cm taller than greenhouse A, greenhouse C is 4.3 cm taller than greenhouse A, and greenhouse C is 0.45 cm taller than greenhouse B. Therefore, it can be seen that among cruciferous crops, 75% coverage rate has the best effect in shortening the crop growth cycle, 50% coverage rate is slightly worse, and ordinary agricultural film is the worst.
[0131] In summary, the cooling effect of radiant cooling films varies under different weather conditions, but it still results in lower temperatures than ordinary greenhouses, demonstrating a good cooling effect. The cooling effect is even more significant in sunny and hot weather. Agricultural greenhouses based on radiant cooling films not only provide cooling but also ensure normal crop growth. By adjusting the coverage rate, crop growth can be accelerated. This indicates the feasibility of applying radiant cooling films in traditional greenhouses.
[0132] Finally, it should be noted that although the above embodiments have been described in the text and drawings of this application, this should not limit the scope of patent protection of this application. Any technical solutions that are based on the essential concept of this application and utilize the content described in the text and drawings of this application, resulting in equivalent structural or procedural substitutions or modifications, as well as the direct or indirect application of the technical solutions of the above embodiments to other related technical fields, are all included within the scope of patent protection of this application.
Claims
1. An agricultural cooling greenhouse based on a radiation-cooling film, characterized in that, include: Greenhouse frame (1); A light-transmitting greenhouse film (2) includes a top greenhouse film (201) fixed to the top surface of the greenhouse frame (1) and a side greenhouse film (202) fixed to the circumferential surface of the greenhouse frame (1); wherein the top greenhouse film (201) and the side greenhouse film (202) surround and form a planting space. Radiation cooling film (3), the radiation cooling film (3) is fixed on the top surface of the top greenhouse film (201) and is used to radiate heat from the planting space to reduce the temperature in the planting space; A light-transmitting plate guard (4) is located on the top surface of the radiation cooling film (3).
2. The agricultural cooling greenhouse based on a radiation-cooling film according to claim 1, characterized in that, The top canopy film (201) includes several reflective areas and several exposed light-transmitting areas (2011). Only the reflective areas of each of the aforementioned films are provided with the radiation cooling film (3) and the light-transmitting plate guard plate (4).
3. The agricultural cooling greenhouse based on a radiation-cooling film according to claim 2, characterized in that, The top film (201) includes two inclined top surfaces arranged in a pointed structure, and each of the film-coated reflective areas and each of the exposed light-transmitting areas (2011) are arranged at intervals along the length direction of the inclined top surfaces.
4. The agricultural cooling greenhouse based on a radiative cooling film according to claim 2, characterized in that, The top canopy film (201) has an arc-shaped structure that arches upwards in the middle.
5. The agricultural cooling greenhouse based on a radiation-cooling film according to claim 4, characterized in that, Each of the film-coated reflective areas and each of the exposed light-transmitting areas (2011) are arranged at intervals along the length of the top film (201).
6. The agricultural cooling greenhouse based on a radiation-cooling film according to claim 4, characterized in that, Each of the film-coated reflective areas and each of the exposed light-transmitting areas (2011) are arranged at intervals around the axis of the top film (201).
7. The agricultural cooling greenhouse based on a radiation-cooling film according to claim 4, characterized in that, The reflective areas of each of the aforementioned films and the exposed light-transmitting areas (2011) are arranged in an alternating pattern of black and white squares on a chessboard.
8. The agricultural cooling greenhouse based on a radiation-cooling film according to claim 2, characterized in that, All of the aforementioned reflective areas of the film are clustered on one side, and all of the aforementioned exposed light-transmitting areas (2011) are clustered on the other side.
9. The agricultural cooling greenhouse based on a radiation-cooling film according to claim 1, characterized in that, The top canopy (201) is a continuous sloping structure that slopes downwards from one end to the other.