A greenhouse light-heat synergic regulation system, a regulation method and application thereof

Abstract

The application discloses a greenhouse light-heat synergic regulation system, a regulation method and application, and belongs to the technical field of agricultural facility engineering and intelligent light-heat regulation materials. The system comprises a greenhouse top spectrum regulation component and a ground surface reflection component. The top component is a sandwich structure, and a PDH temperature-sensitive spectrum regulation layer is arranged in the sandwich structure. The top component is high in light transmittance at low temperature, and is changed into a state of high scattering and high near-infrared reflection at high temperature. In addition, the top component adopts an asymmetric substrate thickness design to realize day and night heat buffering. The ground surface reflection component reflects light, which is transmitted through a canopy gap, to the middle and lower parts of the canopy and the back of leaves. The application realizes the synergy of top heat suppression and bottom light supplement. In summer, the application can reduce indoor temperature, improve the light energy utilization rate of the canopy, reduce the cooling energy consumption, and is suitable for the cultivation and seedling of various greenhouses, vegetables, flowers and medicinal plants.

Description

Technical Field

[0001] This invention relates to the field of agricultural facility engineering and intelligent photothermal regulation materials technology, specifically to a greenhouse photothermal synergistic regulation system, regulation method and application. Background Technology

[0002] Greenhouse agriculture utilizes covering materials to regulate the crop growth environment, achieving, to a certain extent, temperature control, insulation, rain protection, and stable production. Currently, glass greenhouses are widely used for year-round production of vegetables, flowers, seedlings, and high-value-added crops due to their excellent light transmission, long service life, and high structural stability. Existing glass greenhouses typically use ordinary transparent glass, ultra-clear glass, or other high-transmittance covering materials for their roofs to ensure sufficient solar radiation enters the greenhouse, providing an energy source for crop photosynthesis.

[0003] However, in practical applications, sunlight entering a greenhouse includes not only photosynthetically active radiation (PAR), which is beneficial to plant growth, but also a large amount of near-infrared radiation (NIR), which can easily cause temperature increases. Especially under the high temperature and high radiation conditions of spring and summer, ordinary transparent greenhouse covering materials usually lack the ability to selectively regulate different wavelengths of solar radiation, allowing a large amount of near-infrared radiation to penetrate into the greenhouse and be converted into heat, leading to a rapid increase in temperature inside the greenhouse. Excessive temperature can cause problems such as transpiration imbalance, leaf scorching, inhibited photosynthesis, and stunted growth and development, which are detrimental to high-yield and high-quality crop growth.

[0004] To address the issue of high temperatures in greenhouses, existing technologies typically employ external shading, internal shading, natural ventilation, fan-assisted cooling, and misting to regulate the greenhouse environment. While these methods can reduce indoor temperatures to some extent, they generally suffer from the following drawbacks: First, the systems are complex and energy-intensive, increasing greenhouse construction and operating costs. Second, while shading reduces heat load, it often significantly weakens light intensity, leading to a decrease in photosynthetically active radiation entering the greenhouse, which is detrimental to crop photosynthesis. Third, some cooling measures are highly dependent on environmental conditions, and their effectiveness is easily affected by external climate, resulting in limited stability.

[0005] On the other hand, from the perspective of crop light reception, traditional transparent greenhouse covering materials allow strong, direct sunlight to enter the greenhouse. Sunlight primarily affects the upper leaf surfaces of the plant canopy, while the middle and lower leaves and the undersides of leaves receive relatively insufficient light, resulting in uneven light distribution within the canopy and low overall light energy utilization efficiency. Although some existing diffuse scattering covering materials can improve light uniformity to some extent, they still have shortcomings in temperature response regulation, near-infrared reflection suppression, and synergistic utilization with surface reflection within the greenhouse, making it difficult to simultaneously meet the greenhouse cooling needs and the crop's need for efficient light reception.

[0006] Furthermore, greenhouse surfaces are typically covered with mulch to achieve functions such as moisture retention, weed control, and temperature regulation. Different colors and reflective properties of mulch can affect the secondary light environment inside the greenhouse. Currently, there is a lack of systematic research and engineering integration of using high-reflectivity mulch to reflect light passing through canopy gaps back to the lower surface of leaves and the middle and lower canopy layers, thereby improving the uniformity of light exposure and light energy utilization for the entire plant. In particular, there is a lack of effective solutions for coordinating the design of spectrally selective control materials at the greenhouse roof with surface reflective materials to simultaneously suppress heat input and optimize canopy light exposure.

[0007] Therefore, there is an urgent need for a greenhouse photothermal control technology that can be applied to the top of a greenhouse, automatically adjust its optical performance according to temperature changes, selectively control different bands of solar radiation, and work in synergy with the reflective mulch film inside the greenhouse, in order to improve the greenhouse thermal environment and crop light environment and increase crop growth efficiency. Summary of the Invention

[0008] To address the problems of existing greenhouse covering materials lacking selective control over solar radiation, easily leading to heat accumulation inside the greenhouse under high-temperature conditions, traditional shading and cooling measures causing loss of photosynthetically effective radiation, and uneven light distribution within the crop canopy, this invention aims to provide a greenhouse photothermal synergistic control system, control method, and application to solve the following technical problems: To address the problem that existing transparent greenhouse covering materials have insufficient ability to suppress near-infrared radiation, which can easily lead to excessively high internal temperatures and thus affect the normal growth of plants; To address the problem that existing shading or cooling methods, while reducing greenhouse heat load, can easily excessively weaken light intensity and affect the entry of photosynthetically active radiation into the greenhouse; To address the problem that in existing greenhouses, most incident light acts directly on the upper part of the plant canopy, resulting in insufficient light for the middle and lower leaves and the undersides of leaves, and uneven light distribution throughout the canopy; To address the lack of coordinated design between existing greenhouse roof light-switching materials and ground surface reflection regulation, which makes it difficult to simultaneously optimize the greenhouse thermal environment and ensure efficient crop light reception; How to provide a photothermal synergistic control system that can be installed on the top of a greenhouse, automatically changes its optical state when the temperature rises, reflects the near-infrared band of solar radiation, and allows photosynthetically active radiation to enter the greenhouse in the form of scattering, so as to improve the greenhouse's environmental control capabilities and the plant's light energy utilization efficiency.

[0009] To address the problem of insufficient day and night heat transfer regulation capacity in the symmetrical upper and lower layers of existing sandwich greenhouse covering components, an asymmetrical heat transfer structure is formed by making the thickness of the outer transparent substrate greater than that of the inner transparent substrate. This reduces the instantaneous rate of heat transfer from the outside to the temperature-sensitive functional layer and the interior of the greenhouse under high temperature and high radiation conditions during the day, and promotes the slow release of heat accumulated in the temperature-sensitive functional layer and sandwich components into the interior of the greenhouse at night or when the temperature is low. To address the problem of fixed arrangement of top control components under different geographical locations, orientations, and climates, making it difficult to balance cooling and lighting, modular, zoned, or interval installation is used to combine hydrogel laminated glass and ordinary transparent glass according to predetermined area ratios and positional relationships. To address the issues of limited installation methods and difficulty in matching the reflection direction to crop canopies, the placement, width, spacing, tilt angle, or orientation of the reflective film blocks is determined based on the solar altitude angle, solar azimuth angle, greenhouse orientation, crop row spacing, plant height, and canopy density at the greenhouse location. This increases the effective proportion of reflected light reaching the underside of leaves and the lower and middle layers of the canopy.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a greenhouse light and heat synergistic control system, comprising: A greenhouse top spectral control component, which is set in the top and / or side light-receiving area of ​​the greenhouse, includes a first transparent substrate, a second transparent substrate, and a temperature-sensitive spectral control layer disposed between the two; the temperature-sensitive spectral control layer is configured to: maintain a high light transmittance state when the temperature is below a preset threshold, and switch to a high scattering and near-infrared high reflectance state when the temperature is above the preset threshold, so as to selectively transmit photosynthetically effective radiation and reflect near-infrared radiation. The ground reflector is laid on the ground surface of the planting area inside the greenhouse. It is used to reflect and scatter light that passes through the gaps in the crop canopy upwards to the lower part of the crop canopy and the back of the leaves. It works in conjunction with the spectral control component at the top of the greenhouse to achieve joint control of the thermal and light environments inside the greenhouse.

[0011] As a preferred embodiment of the present invention, the temperature-sensitive spectral control layer is a PDH hydrogel layer, and the PDH hydrogel layer is sealed between the first transparent substrate and the second transparent substrate by a peripheral encapsulation sealing layer.

[0012] As a preferred embodiment of the present invention, the first transparent substrate is an outer substrate facing the outside atmosphere, the second transparent substrate is an inner substrate facing the inside of the greenhouse, and the thickness of the first transparent substrate is greater than the thickness of the second transparent substrate, forming an asymmetric heat transfer sandwich structure.

[0013] As a preferred embodiment of the present invention, the thickness ratio of the first transparent substrate to the second transparent substrate is 1.1:1-5:1.

[0014] As a preferred embodiment of the present invention, the first transparent substrate is ultra-white glass, tempered glass or laminated glass, and the second transparent substrate is ultra-white glass, transparent polymer board or flexible transparent encapsulation layer.

[0015] As a preferred technical solution of the present invention, the greenhouse top spectral control component is a modular structure, and multiple independent greenhouse top spectral control components are combined with ordinary light-transmitting covering materials and installed in the greenhouse top lighting area. The installation area of ​​the greenhouse top spectral control component accounts for 10-100% of the total area of ​​the greenhouse top lighting area.

[0016] As a preferred embodiment of the present invention, the surface reflective component is a silver-white ground film, a high-reflectivity diffuse reflective ground film, a metallized reflective film, or a microstructured diffuse reflective film.

[0017] As a preferred embodiment of the present invention, it further includes an installation support structure and an optional environmental control unit. The installation support structure is used to fix the greenhouse top spectral control component to the greenhouse top. The environmental control unit includes a ventilation device, a heat preservation device, a shading device, an irrigation device, or a spraying device.

[0018] Secondly, the present invention also provides a method for coordinated control of greenhouse light and heat, comprising the following steps: S1: Install the greenhouse top spectral control component as described in any one of claims 1-8 in the greenhouse top light-receiving area; S2: Lay the ground surface of the planting area inside the greenhouse with the ground reflective components as described in any one of claims 1-8; S3: The spectral control component at the top of the greenhouse automatically controls the spectral composition and propagation mode of the incident solar radiation according to the ambient temperature. When the temperature is below the preset threshold, a high proportion of sunlight passes through into the greenhouse. When the temperature is above the preset threshold, near-infrared radiation is reflected and photosynthetically active radiation enters the greenhouse in the form of scattering. S4: The surface reflector is used to reflect the photosynthetically active radiation that passes through the gaps in the crop canopy to the lower part of the crop canopy and the back of the leaves, thereby achieving coordinated regulation of top heat suppression and bottom supplemental lighting.

[0019] Thirdly, the present invention also provides an application of a greenhouse light and heat synergistic control system, which is applied to solar greenhouses, glass greenhouses, multi-span greenhouses, scientific research greenhouses and high-value-added facility agriculture cultivation environments for the cultivation and seedling raising of vegetables, fruits, flowers and medicinal plants.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention effectively reduces the heat load inside greenhouses and alleviates high-temperature stress. By installing a spectral modulation component with a temperature-sensitive functional layer at the top of the greenhouse, it changes its optical state when the temperature rises, thereby reflecting most of the near-infrared band of solar radiation and reducing the amount of near-infrared radiation entering the greenhouse and being converted into heat. Therefore, compared to ordinary transparent greenhouse covering materials, this invention can effectively suppress the temperature rise inside the greenhouse under high-temperature conditions, reducing the risk of crop growth stunts caused by high temperatures.

[0021] This invention reduces heat input while preserving the effective light required for crop growth. Existing shading or cooling methods typically weaken solar radiation by reducing overall light transmittance. While this can lower greenhouse temperature to some extent, it also tends to reduce the entry of photosynthetically active radiation, which is detrimental to normal plant photosynthesis. This invention uses a top-mounted spectral control component to selectively regulate solar radiation in different wavelengths. This suppresses near-infrared heat input while allowing at least a portion of the photosynthetically active radiation to still enter the greenhouse, thus balancing greenhouse cooling with plant light requirements.

[0022] This invention converts transmitted light into soft, diffused light, improving the uniformity of light exposure in the canopy. In this invention, the temperature-sensitive functional layer transforms transmitted light from traditional direct light into diffused light at high temperatures. Compared to ordinary transparent covering materials, the diffused light propagates more dispersedly within the greenhouse, making it more effective at penetrating the plant canopy. This reduces the difference between excessive light exposure to the top leaves and insufficient light exposure to the middle and lower leaves, thus improving the overall light distribution within the crop canopy.

[0023] This invention improves the light reception level of the lower surface of plant leaves and the middle and lower canopy areas. By installing a reflective mulch film on the greenhouse floor, light reaching the ground through the gaps in the plant leaves is reflected and scattered upwards again. As a result, some light that would otherwise be difficult for the upper leaves to capture can be redirected to the underside of the leaves and the middle and lower canopy areas, improving the problem of insufficient light reception for the lower leaves in traditional greenhouses and enhancing the overall light reception efficiency of the plant.

[0024] This invention achieves a synergistic effect of top lighting and bottom supplemental lighting, improving light energy utilization efficiency. Instead of relying solely on a single top covering material for light control, this invention utilizes a synergistic design of a top temperature-sensitive lighting component and a ground surface reflector. This design allows light to undergo a process within the greenhouse: selective transmission and scattering from the top, propagation through the canopy, secondary reflection from the ground surface, and then a second application to the canopy. This synergistic effect helps improve light utilization within the crop population and enhances the greenhouse's light environment control effect.

[0025] The system structure of this invention is relatively clear, making it easy to integrate with existing greenhouse facilities. The top spectral control component of this invention adopts a sandwich structure and can be directly replaced and installed as a light-transmitting component at the top of the greenhouse; the ground-level reflective component can be installed on the ground or between crop rows using common film-laying methods. Therefore, this invention has good engineering adaptability in its structure, facilitating integration with existing greenhouse facilities and its widespread application.

[0026] This invention is beneficial for improving the comprehensive regulation of the crop growth environment. By simultaneously improving the greenhouse thermal environment and the crop canopy light environment, this invention enables the greenhouse to meet both cooling and light requirements under high radiation and high temperature conditions, thereby creating more suitable light and heat conditions for plant growth, and thus improving crop growth efficiency and production stability.

[0027] This invention achieves better day-night temperature buffering. Through an asymmetrical sandwich structure with a thicker outer layer and a thinner inner layer, the outer transparent substrate provides greater thermal buffering and structural protection under high daytime temperatures and strong sunlight, reducing the tendency for external heat to rapidly enter the greenhouse. Simultaneously, the thinner inner substrate allows some of the heat accumulated in the sandwich components and hydrogel layer to be more easily and slowly released into the greenhouse at night or when temperatures are low, helping to reduce the risk of chilling injury caused by excessively low nighttime temperatures.

[0028] This invention improves the system's adaptability to different regions and seasons. By adjusting the installation area, location, and spacing ratio of the hydrogel laminated glass module with ordinary glass at the top of the greenhouse, this invention allows for differentiated configuration based on high-temperature areas, low-light areas, areas with large diurnal temperature differences, and the light requirements of different crops, avoiding excessive shading or insufficient cooling caused by a single full-coverage method.

[0029] This invention improves the effectiveness of bottom reflective supplemental lighting. By arranging the position and reflection angle of the reflective film blocks according to the direction of solar incidence, greenhouse orientation, crop row direction, and canopy morphology, this invention enables more secondary reflected light to enter the back of the leaves and the middle and lower canopy areas, increasing the effective utilization rate of reflected light and thus enhancing the synergistic effect between the top light-adjusting components and the ground-level reflective components. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the greenhouse photothermal synergistic control system of the present invention. Figure 2 This is a schematic diagram of the cross-sectional structure of the spectral control component at the top of the greenhouse in this invention. Figure 3 This is a schematic diagram showing the working state of the temperature-sensitive functional layer under different temperature conditions in this invention. Figure 4 This is a schematic diagram of the light path propagation process inside the greenhouse in this invention.

[0031] In the figure: 1. Spectral control component at the top of the greenhouse; 101. First transparent substrate; 102. Second transparent substrate; 103. Temperature-sensitive spectral control layer; 104. Encapsulation and sealing layer; 2. Ground surface reflective component; 3. Installation support structure. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples. However, it should be understood that the accompanying drawings are for illustrative purposes only and should not be construed as limiting the present patent. For better illustration of this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable that some well-known structures and their descriptions may be omitted in the drawings for those skilled in the art. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting the present patent.

[0033] This invention relates to the field of agricultural facility engineering and intelligent photothermal regulation materials technology, specifically a greenhouse photothermal regulation system, method, and application based on the synergy of PDH temperature-sensitive hydrogel and surface reflection. This invention addresses core problems in existing greenhouse technology, such as the prominent contradiction between high-temperature heat damage and insufficient light, uneven canopy light distribution, lack of synergy between top lighting and bottom supplemental lighting, and weak day-night temperature regulation capabilities. Through an integrated design of spectral selective regulation of the greenhouse top and secondary surface reflection supplemental lighting, it achieves simultaneous improvement in greenhouse thermal environment suppression and crop light environment optimization. The following describes the specific implementation of this invention from aspects such as the overall system structure, detailed design of core components, regulation method flow, typical application examples, and synergistic working principle.

[0034] The core of the greenhouse light and heat synergistic control system of this invention consists of a greenhouse roof spectral control component 1, a ground surface reflection component 2, an installation support structure 3, and an optional environmental control unit. The overall system structure is as follows: Figure 1 As shown, the greenhouse top spectral control component 1 is installed in the top and / or side lighting areas of the greenhouse, serving as the main light-transmitting covering layer of the greenhouse and undertaking the functions of spectral selective control of solar radiation and temperature-responsive light adjustment; the ground surface reflection component 2 is laid on the ground surface of the planting area inside the greenhouse, undertaking the functions of secondary reflection and light path redistribution of light transmitted through the canopy; the installation support structure 3 is used to fix the top spectral control component 1 to the main frame of the greenhouse; the environmental control unit serves as an auxiliary system, working in conjunction with the core control system to achieve more precise greenhouse environmental control.

[0035] The core design logic of the system is the synergistic effect of top heat suppression and bottom supplementary lighting: the top component reflects near-infrared radiation at high temperatures to suppress heat input through the optical state change of temperature-sensitive material, while converting photosynthetically active radiation into scattered light to improve the uniformity of light reception in the canopy; the bottom component reflects the light that is not intercepted by the upper part of the canopy upwards to supplement the insufficient light in the middle and lower parts of the canopy and the back of the leaves. Together, the two achieve efficient utilization of light and heat resources.

[0036] The spectral control component 1 at the top of the greenhouse is the core functional unit of this system. It is a sandwich-type composite light-transmitting structure, and its cross-sectional structure is as follows: Figure 2 As shown, the structure includes a first transparent substrate 101, a second transparent substrate 102, a temperature-sensitive spectral control layer 103, and an encapsulation sealing layer 104. The first and second transparent substrates 101 and 102 primarily function as supports, light-transmitting elements, protectors, and encapsulation interfaces. The temperature-sensitive spectral control layer 103 primarily functions for temperature response and optical control. The encapsulation sealing layer 104 primarily prevents the functional layers from losing water, becoming damp, contaminated, or leaking from the interlayer, and improves the overall structure's stability and durability in outdoor environments. The following provides a detailed description of the material selection, structural parameters, design principles, and implementation methods for each component.

[0037] The first transparent substrate 101 is the outer substrate facing the outside atmosphere, and the second transparent substrate 102 is the inner substrate facing the inside of the greenhouse. The thickness of the first transparent substrate 101 is greater than the thickness of the second transparent substrate 102, forming an asymmetric heat transfer sandwich structure. Through this asymmetric thickness design, the outer transparent substrate can provide higher mechanical strength, wind pressure resistance, and weather protection, while increasing the heat capacity and heat transfer path of the outer heated surface. Under strong summer radiation conditions, it reduces the instantaneous rate of external heat transfer to the PDH hydrogel layer and the inside of the greenhouse. The inner transparent substrate is relatively thin, which can reduce the heat transfer resistance of the sandwich structure facing the inside of the greenhouse. This allows some of the heat accumulated by the PDH hydrogel layer and sandwich structure during the day to be more easily and slowly released into the inside of the greenhouse at night or when the outside temperature drops, thereby reducing the risk of excessively low greenhouse temperatures at night.

[0038] The first transparent substrate 101 (outer side) is preferably made of ultra-clear glass, tempered glass, or laminated glass. Among them, ultra-clear glass has a visible light transmittance of ≥91%, which can minimize the loss of photosynthetically active radiation; tempered glass has an impact resistance of more than 5 times that of ordinary glass and a wind pressure resistance of up to 2.5 kPa, which can meet the structural safety requirements of the greenhouse roof; laminated glass will not fall off after breakage, providing higher safety and making it suitable for scientific research greenhouses or sightseeing greenhouses with frequent personnel activities.

[0039] The second transparent substrate 102 (inner side) can be made of ultra-clear glass, a transparent polymer board, or a flexible transparent encapsulation layer. The transparent polymer board is preferably made of polycarbonate (PC) board or polymethyl methacrylate (PMMA) board, which weighs only half that of glass and can reduce the load on the greenhouse roof. The flexible transparent encapsulation layer can be made of ethylene-vinyl acetate (EVA) film or polyolefin (PO) film, which is suitable for making lightweight flexible control components and is applicable to light steel structure greenhouses or arched greenhouses.

[0040] The thickness ratio of the first transparent substrate 101 to the second transparent substrate 102 is 1.1:1-5:1, preferably 1.5:1-3:1. This parameter range is determined comprehensively based on the diurnal temperature difference, roof load-bearing capacity, and thermal management requirements of different climate zones: when the thickness ratio is 1.1:1-1.5:1, the thermal buffering effect of the asymmetric structure is weaker, but the light transmittance is better, making it suitable for southern regions with small diurnal temperature differences (such as South China); when the thickness ratio is 1.5:1-3:1, the thermal buffering and heat storage and slow release effects achieve the optimal balance, making it suitable for regions with moderate diurnal temperature differences, such as the Yangtze River Basin and the Yellow River Basin; when the thickness ratio is 3:1-5:1, the thermal buffering effect is the strongest, which can significantly delay the heat transfer during the day, while the heat storage and release time at night is longer, making it suitable for regions with large diurnal temperature differences, such as Northwest and Northeast China. The above-mentioned thickness difference is not limited to specific materials, but is used to form asymmetric photothermal control components with different thermal resistances and different heat capacities from the outside to the inside.

[0041] In some embodiments, the outer first transparent substrate is made of 6mm thick ultra-clear tempered glass, and the inner second transparent substrate is made of 3mm thick ultra-clear glass, with a thickness ratio of 2:1. Thermal testing shows that at midday in summer, this structure reduces the instantaneous heat transfer rate from the outside to the greenhouse by 28% compared to a symmetrical sandwich structure (6mm + 6mm glass); at night, the rate of heat release from the sandwich layer to the greenhouse is increased by 35%, raising the minimum nighttime temperature of the greenhouse by 1.5-2.5℃, effectively reducing the risk of chilling injury to crops.

[0042] The temperature-sensitive spectral control layer 103 is a PDH hydrogel layer, sealed between the first transparent substrate 101 and the second transparent substrate 102 by a peripheral encapsulation sealing layer 104. PDH hydrogel is a smart polymer material with temperature-responsive properties; its optical state undergoes a reversible change with temperature. Its working principle is as follows: Figure 3 As shown. PDH hydrogel is a known hydrogel material and can be prepared using methods known in the art or methods previously disclosed by the applicant.

[0043] PDH hydrogel layers exhibit temperature-responsive properties, displaying different optical states under varying temperature conditions. When the temperature is below the preset threshold, the PDH hydrogel molecular chains are in a stretched state with a uniform internal structure and extremely weak light scattering. At this time, the hydrogel layer maintains a high light transmittance, with a visible light (400-700nm, photosynthetically active radiation PAR) transmittance ≥85% and a near-infrared radiation (700-2500nm, NIR) transmittance ≥80%, which can ensure that sunlight can fully enter the greenhouse and meet the needs of crop photosynthesis.

[0044] When the temperature exceeds a preset threshold, the PDH hydrogel molecular chains coil, forming numerous nanoscale hydrophobic microdomains within. These microdomains exhibit a significant difference in refractive index compared to the hydrogel matrix, causing the hydrogel layer to transform into a highly scattering, near-infrared highly reflective state. At this point, the near-infrared radiation reflectivity is ≥85%, effectively reflecting most of the thermal radiation back to the outside atmosphere and suppressing the temperature rise inside the greenhouse. Simultaneously, it allows a portion of the photosynthetically active radiation to continue passing through the components into the greenhouse, transforming the transmitted photosynthetically active radiation from direct light into softly scattered light. This improves the uniformity of light exposure to the crop canopy within the greenhouse, preventing direct light from scorching the crop leaves, and allowing the scattered light to more easily penetrate the crop canopy.

[0045] The sealing layer 104 uses weather-resistant silicone sealant or butyl rubber sealant, continuously sealing along the perimeter of the interlayer with a sealing width ≥5mm. Its main functions include: preventing the PDH hydrogel layer from losing water and failing, isolating it from external moisture and dust contamination, and improving the mechanical strength and durability of the interlayer structure. Accelerated aging tests show that the control components using this encapsulation method have a service life ≥10 years in outdoor environments, with an optical performance degradation rate ≤10%.

[0046] The greenhouse roof spectral control component 1 is a modular structure. Multiple independent control components are combined with ordinary light-transmitting covering material and installed in the greenhouse roof's light-receiving area, occupying 10-100% of the total roof's light-receiving area. This modular design solves the problem of inconsistent control effects under different regional and climatic conditions, allowing for flexible configuration according to actual needs. The size of a single control module can be customized according to the greenhouse roof module, with common specifications being 1000mm×1000mm, 1200mm×1000mm, and 1500mm×1000mm. During installation, the modules are fixed to the greenhouse roof joists using aluminum alloy mounting support structure 3, and weather-resistant sealing strips are used between modules to ensure the roof's waterproof performance.

[0047] The installation area ratio and layout need to be determined based on the latitude, altitude, climate type, crop light requirements, and high-temperature period characteristics of the greenhouse location. In high-temperature and high-radiation areas: the installation ratio is 60-100%, using a strip-style full-coverage arrangement, continuously installed along the slope of the greenhouse roof, which can maximize the reflection of near-infrared radiation and reduce the indoor temperature in summer.

[0048] In hot summer and cold winter regions: the installation ratio is 40-70%, with a checkerboard-style interval arrangement. The control module and ordinary ultra-clear glass are installed alternately to take into account both summer cooling and winter lighting needs.

[0049] In regions with short summers and long winters: the installation ratio is 20-40%, with priority given to key areas, such as greenhouse ridges, west-facing walls, and areas with strong midday direct sunlight. This can alleviate the short-term high-temperature stress in summer without affecting winter lighting and warming.

[0050] In some embodiments, a multi-span glass greenhouse located in a certain area has a span of 8m, a bay width of 4m, and a total roof light-receiving area of ​​3200m². 2 The greenhouse employs a checkerboard layout with a 50% installation ratio, housing 1600 1000mm×1000mm PDH hydrogel control modules. Actual measurements show that the highest indoor temperature at midday in summer is 3.8-4.5℃ lower than in a conventional glass greenhouse, and the indoor light transmittance on sunny winter days is only 8% lower, effectively meeting the light and heat requirements for year-round tomato production.

[0051] The surface reflective component 2 is preferably a silver-white mulch film, a high-reflectivity diffuse reflective mulch film, a metallized reflective film, or other surface covering materials with high visible light reflectivity. The surface reflective component is laid on the surface of the greenhouse, between crop rows, on the ridge surface, or on the surface of the planting trough. Its functions are: (1) to receive light that reaches the ground through the gaps between plant leaves; (2) to reflect or scatter the received light upwards again; (3) to allow the reflected light to illuminate the lower surface of plant leaves and the lower part of the canopy; and (4) to improve the problem of insufficient light for the lower leaves and the back leaves of plants under traditional direct sunlight conditions.

[0052] In a preferred embodiment, the surface reflective components 2 are not simply laid out in a flat, continuous manner. Instead, they are laid out in a zoned, strip, block, or partially inclined manner according to the solar altitude angle, solar azimuth angle, greenhouse roof orientation, crop row direction, plant spacing, row spacing, and canopy height. The reflective components can be placed on one side of the crop row, on both sides of the crop row, in the furrow area, on the sidewall of the planting trough, under the plants, or on adjustable supports, with their reflective surfaces facing the target canopy area. This allows more light transmitted through the top spectral control components and the gaps in the crop canopy to be reflected onto the back of the leaves, the middle and lower leaves, or areas with insufficient light.

[0053] Furthermore, the placement, area, width, spacing, and tilt angle of the surface reflective component 2 can be matched with the modular arrangement of the top spectral control component. For example, a reflective film with higher reflectivity can be placed below the scattered light incident area corresponding to the top hydrogel laminated glass module, while reflective films with different reflection angles or reflectivities can be placed in the direct light incident area corresponding to ordinary glass, so as to achieve effective supplementary lighting under different incident light conditions.

[0054] The greenhouse light and heat synergistic regulation method of the present invention includes the following four core steps, and the specific operation process and technical requirements of each step are as follows: Step S1: Installation of the spectral control components on the greenhouse roof 1. Preliminary survey and design: Measure the area, slope, orientation, and spacing of the roof light-receiving area of ​​the greenhouse. Based on local climate conditions and crop type, determine the installation area ratio, layout, and structural parameters of the control modules.

[0055] 2. Installation of support structure: Aluminum alloy profiles are used to make the installation keel, which is fixed to the main frame of the greenhouse with bolts to ensure that the horizontal and vertical errors of the keel are ≤2mm / m.

[0056] 3. Installation of control modules: Place the prefabricated PDH hydrogel control modules on the keel and fix them with pressure strips and bolts. Seal the gaps between the modules with weather-resistant silicone sealant to ensure the waterproof performance of the roof.

[0057] 4. System debugging: After installation, clean the dust and stains on the module surface, test the optical state transition of the module at different temperatures, and ensure that the temperature response threshold and optical performance meet the design requirements.

[0058] Step S2: Laying of surface reflective components 1. Surface pretreatment: Level the surface of the planting area, remove weeds, stones and other debris, and ensure that the surface flatness error is ≤5cm.

[0059] 2. Reflective film cutting and laying: Cut the reflective film according to the designed laying method and size, and lay it in the predetermined position using a mulch film covering machine or manual laying method. Fix the edges with soil clods or film pressing lines to prevent it from being blown away by the wind.

[0060] 3. Installation quality inspection: Inspect the flatness, fixation and damage of the reflective film, repair damaged parts in time, and ensure that the reflective surface is unobstructed.

[0061] Step S3: Automatic photothermal control of the top spectral control component The spectral control components at the top of the greenhouse automatically switch optical states based on the ambient temperature, requiring no manual intervention. When the ambient temperature is below the preset threshold, the control components maintain a high light transmittance state, and sunlight enters the greenhouse in a high proportion in the form of direct sunlight, providing sufficient light and heat for crop growth.

[0062] When the ambient temperature is higher than the preset threshold, the control component automatically switches to a high scattering and near-infrared high reflectance state, reflecting most of the near-infrared radiation to suppress the indoor temperature rise, while converting photosynthetically active radiation into scattered light to improve the uniformity of light received by the canopy.

[0063] Step S4: Secondary reflection supplementary lighting from surface reflective components After photosynthetically active radiation reaches the ground through the gaps in the crop canopy, it is reflected and scattered upwards again by the surface reflectors, illuminating the lower and middle parts of the crop canopy and the undersides of the leaves. This process, in conjunction with the scattered light from the top control components, forms a complete light path cycle of "top scattered light - upper canopy receiving light - secondary reflection from the ground - lower and middle parts of the canopy and the undersides receiving light," significantly improving the uniformity of light reception and the efficiency of light energy utilization throughout the canopy.

[0064] The optical path propagation and heat flow change process of the system of this invention are as follows: Figure 4 As shown, the operating modes can be divided into low-temperature and high-temperature conditions. The synergistic effects of the two modes are as follows: (a) Low-temperature operating conditions (winter, early morning, evening) At this time, the ambient temperature is below the preset threshold of the PDH hydrogel, and the control component is in a high light transmittance state. Sunlight enters the greenhouse through the control component in a direct manner. Most of the photosynthetically active radiation is intercepted by the upper leaves of the crop canopy for photosynthesis, while a small portion reaches the ground surface through the gaps in the canopy and is reflected by the ground reflection component to the middle and lower parts of the canopy and the back of the leaves, supplementing the lower layers of light. At the same time, the asymmetric heat transfer sandwich structure absorbs and stores some solar heat during the day, and slowly releases the stored heat into the greenhouse when the temperature drops at night, playing a role in nighttime heat preservation and reducing heating energy consumption.

[0065] (ii) High-temperature operating conditions (summer noon and afternoon) At this point, the ambient temperature exceeds a preset threshold, and the control components switch to a high-scattering, near-infrared, high-reflection state. The near-infrared portion of solar radiation is reflected back to the outside atmosphere by the control components, reducing thermal radiation input by approximately 70% and effectively suppressing indoor temperature rise. Photosynthetically active radiation enters the greenhouse in a scattered form, evenly distributed in the upper part of the crop canopy, preventing direct sunlight from scorching the leaves. Scattered light passing through the canopy gaps reaches the ground and is reflected again by the reflective components, further increasing the light intensity in the lower and middle parts of the canopy. At this time, the indoor temperature is 3-5°C lower than in a conventional glass greenhouse, the crop transpiration rate is reduced by 20-25%, and the operating time of cooling equipment such as fans and wet curtains is reduced by 30-40%, significantly reducing greenhouse operating energy consumption.

[0066] This system can also be used in conjunction with existing environmental control units such as ventilation systems, insulation systems, shading systems, irrigation systems, or spray systems to achieve more precise and efficient greenhouse environmental control. In conjunction with ventilation devices: When the indoor temperature exceeds 35°C, natural or mechanical ventilation is activated first, and the near-infrared reflection function of the top spectral control component is used to further reduce the indoor temperature; when the temperature drops below 30°C, the ventilation device is turned off, while the light scattering function of the control component is retained.

[0067] In conjunction with spray devices: When the midday sun is extremely strong in summer but the temperature has not reached the threshold, a micro-spray device can be activated to reduce the surface temperature of the PDH hydrogel layer, prolong its high light transmittance period, and at the same time increase air humidity to alleviate crop transpiration stress.

[0068] In conjunction with insulation devices: When the insulation blanket is closed at night, the heat stored in the asymmetric heat transfer interlayer structure is slowly released. Working together with the insulation blanket, it can raise the greenhouse temperature by 2-3℃ at night and reduce heating energy consumption in winter.

[0069] In conjunction with shading devices: In extreme high-temperature weather (temperatures exceeding 40°C), external shading devices can be used to further reduce the heat load; however, since this system already has a strong cooling capacity, the opening time of the shading device is reduced by more than 50% compared to ordinary greenhouses, effectively avoiding the loss of photosynthetically active radiation caused by shading.

[0070] The above are merely specific embodiments of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A greenhouse photothermal synergistic control system, characterized in that, include: A greenhouse top spectral control component, which is disposed in the top and / or side light-receiving area of ​​the greenhouse, includes a first transparent substrate, a second transparent substrate, and a temperature-sensitive spectral control layer disposed between the two; The temperature-sensitive spectral control layer is configured to maintain a high light transmittance state when the temperature is below a preset threshold, and to switch to a high scattering and near-infrared high reflectance state when the temperature is above a preset threshold, so as to selectively transmit photosynthetically effective radiation and reflect near-infrared radiation. The ground reflector is laid on the ground surface of the planting area inside the greenhouse. It is used to reflect and scatter light that passes through the gaps in the crop canopy upwards to the lower part of the crop canopy and the back of the leaves. It works in conjunction with the spectral control component at the top of the greenhouse to achieve joint control of the thermal and light environments inside the greenhouse.

2. The greenhouse photothermal synergistic control system according to claim 1, characterized in that, The temperature-sensitive spectral modulation layer is a PDH hydrogel layer, which is sealed between the first transparent substrate and the second transparent substrate by a peripheral encapsulation sealing layer.

3. The greenhouse photothermal synergistic control system according to claim 1, characterized in that, The first transparent substrate is the outer substrate facing the outside atmosphere, and the second transparent substrate is the inner substrate facing the inside of the greenhouse. The thickness of the first transparent substrate is greater than the thickness of the second transparent substrate, forming an asymmetric heat transfer sandwich structure.

4. The greenhouse photothermal synergistic control system according to claim 3, characterized in that, The thickness ratio of the first transparent substrate to the second transparent substrate is 1.1:1-5:

1.

5. The greenhouse photothermal synergistic control system according to claim 1, characterized in that, The first transparent substrate is ultra-clear glass, tempered glass or laminated glass, and the second transparent substrate is ultra-clear glass, transparent polymer board or flexible transparent encapsulation layer.

6. The greenhouse photothermal synergistic control system according to claim 1, characterized in that, The greenhouse roof spectral control component is a modular structure. Multiple independent greenhouse roof spectral control components are combined with ordinary light-transmitting covering materials and installed in the greenhouse roof lighting area. The installation area of ​​the greenhouse roof spectral control component accounts for 10-100% of the total area of ​​the greenhouse roof lighting area.

7. The greenhouse photothermal synergistic control system according to claim 1, characterized in that, The surface reflective component is a silver-white ground film, a high-reflectivity diffuse reflective ground film, a metallized reflective film, or a microstructured diffuse reflective film.

8. The greenhouse photothermal synergistic control system according to claim 1, characterized in that, It also includes an installation support structure and an optional environmental control unit. The installation support structure is used to fix the greenhouse top spectral control component to the greenhouse top. The environmental control unit includes a ventilation device, a heat preservation device, a shading device, an irrigation device, or a spraying device.

9. A method for coordinated control of light and heat in a greenhouse, characterized in that, Includes the following steps: S1: Install the greenhouse top spectral control component as described in any one of claims 1-8 in the greenhouse top light-receiving area; S2: Lay the ground surface of the planting area inside the greenhouse with the ground reflective components as described in any one of claims 1-8; S3: The spectral control component at the top of the greenhouse automatically controls the spectral composition and propagation mode of the incident solar radiation according to the ambient temperature. When the temperature is below the preset threshold, a high proportion of sunlight passes through into the greenhouse. When the temperature is above the preset threshold, near-infrared radiation is reflected and photosynthetically active radiation enters the greenhouse in the form of scattering. S4: The surface reflector is used to reflect the photosynthetically active radiation that passes through the gaps in the crop canopy to the lower part of the crop canopy and the back of the leaves, thereby achieving coordinated regulation of top heat suppression and bottom supplemental lighting.

10. The application of the greenhouse photothermal synergistic control system according to any one of claims 1-8, characterized in that, The system is applied to greenhouses, glass greenhouses, multi-span greenhouses, scientific research greenhouses, and high-value-added facility agriculture cultivation environments for the cultivation and seedling raising of vegetables, fruits, flowers, and medicinal plants.

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