Roof canal photovoltaic system

Abstract

The utility model provides a gutter photovoltaic system which comprises a water pipe, a photovoltaic battery assembly, a towering support and a water pipe photovoltaic assembly array transversely hung above a farmland, and the gutter photovoltaic system is like a gutter. According to the invention, a photovoltaic power generation system and an agricultural irrigation system are combined into one; solar energy can be collected for power generation while precise and efficient irrigation is achieved, so that the dual technical effects of irrigation and power generation are achieved, the benefits of photovoltaic power generation can be supplemented back to agriculture, and irrigation, fertilization and pesticide spraying services are provided for the agriculture.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of agricultural light complementation and agricultural irrigation, and particularly relates to a sky channel photovoltaic system. BACKGROUND

[0002] As a prominent representative of ancient water conservancy projects in China, the Zhengguo Canal has profound historical significance not only due to its large-scale irrigation but also because it opened up a new era for the development of agricultural civilization. With the increasing global population and the growing demand for agricultural productivity, modern agriculture has become increasingly demanding in terms of irrigation technology. The continuous development of irrigation technology has enabled farmers to more effectively utilize limited water resources to meet the growth needs of crops. Among these, drip irrigation and sprinkler irrigation are two advanced irrigation methods widely used today. However, while these two techniques have significant advantages in water conservation, they also present some non-negligible issues, particularly in terms of coordination with agricultural machinery. These issues not only affect agricultural productivity but also result in unnecessary waste of arable land resources. Drip irrigation is a method of delivering water directly to the root zone of plants, offering significant water-saving benefits. By burying or laying water pipes in the root zone of crops, drip irrigation allows for precise control of water quantity, avoiding waste of water resources. However, this technology faces limitations in practical application: water pipe laying affects mechanical operations, and the water pipes of the drip irrigation system usually need to be laid in the farmland, which poses an obstacle to agricultural machinery operations. When agricultural machinery performs operations such as plowing, sowing, and harvesting in the field, it is easily affected by the water pipes, leading to inconvenience and even damage to equipment. Furthermore, the drip irrigation system needs to be removed before the harvesting season, which is time-consuming and labor-intensive, increasing the complexity and cost of agricultural production. Maintenance difficulties, as the water pipes of the drip irrigation system are easily covered by soil, weeds, and other obstacles during long-term use, maintenance and repair become difficult. Once clogged or damaged, the repair process is complex and may require stopping irrigation operations, which is extremely detrimental to the normal growth of crops. Short water pipe lifespan, due to the long-term exposure of water pipes to ultraviolet light, temperature changes, and mechanical pressure, their service life is limited, and frequent replacement increases costs. Sprinkler irrigation is a method of simulating natural rainfall by spraying water onto the crops. The sprinkler irrigation system is usually composed of sprinklers, water pumps, and pipelines, which can cover a large area of farmland and provide uniform irrigation. However, in practical application, sprinkler irrigation technology also faces some challenges: irrigation vehicles affect farmland, and the sprinkler irrigation system requires irrigation vehicles to move in the field for operation. However, when irrigation vehicles drive in the field, they can crush crops, especially during the growing season, causing direct economic losses. To avoid this problem, farmers usually need to reserve a path in the field for the irrigation vehicles to pass through. However, this reservation of a path leads to waste of arable land resources, reducing the actual available planting area and affecting overall yield. Water resource waste, although sprinkler irrigation technology saves water resources compared to traditional irrigation methods, there is still some water resource waste due to evaporation and wind during the spraying process. Additionally, during sprinkler irrigation, not all water reaches the crop roots, but some remains on the leaves or surface, which cannot be effectively absorbed by the crops.The initial investment of the sprinkler system is relatively high, and a large amount of energy is consumed during daily operation, especially when irrigating large areas. In addition, regular maintenance and replacement of the sprinkler equipment also require a considerable expenditure. While drip irrigation and sprinkler technology improve the efficiency of agricultural water use, they also have an impact on the use of arable land. First, the laying of water pipes for drip irrigation systems and the reservation of lanes for sprinkler systems require the use of part of the arable land, reducing the actual planting area. This waste is particularly significant in large-scale agricultural production, especially in areas where arable land resources are scarce, and cannot be ignored. Second, the operation of irrigation vehicles in the field not only damages crops but also causes some damage to the soil structure, affecting the long-term fertility of the soil and the growth conditions of crops. This destructive effect gradually accumulates in farmland that has been using sprinkler technology for a long time, which may lead to soil compaction and reduced water permeability, thereby affecting crop yield and quality.

[0003] In view of the above problems existing in the current drip irrigation and sprinkler technology in practical application, researchers in the industry have been studying how to further improve irrigation efficiency without hindering agricultural machinery cultivation, reduce water waste, and maximize the use of arable land to promote the development of modern agriculture to a higher level. SUMMARY

[0004] The purpose of the present application is to provide a sky channel photovoltaic system to achieve precise and efficient irrigation while collecting solar power generation, forming dual benefits of irrigation and power generation, and to provide irrigation, fertilization, and pesticide services for agriculture through photovoltaic power generation income.

[0005] In order to achieve the above-mentioned purpose of the application, the sky channel photovoltaic system provided by the present application is as follows.

[0006] The sky channel photovoltaic system of the present application is characterized in that it comprises:

[0007] ① (irrigation) water pipes and photovoltaic cell assemblies for power generation, which are combined into an elongated water pipe photovoltaic assembly that can both receive sunlight for power generation and deliver water to farmland for irrigation, i.e., a linear water pipe photovoltaic assembly;

[0008] ②a high-rise support and a plurality of water-pipe photovoltaic modules arranged in intervals and suspended above farmland by load-bearing cables; the width of the water-pipe photovoltaic module is D (diameter if circular), the height of the water-pipe photovoltaic module is H, the span of the water-pipe photovoltaic module is L, and the horizontal projection distance of the water-pipe photovoltaic module is K, wherein D is less than a set width size, H is greater than a set height size, L is greater than a set span size, and K is greater than a set distance size; the water pipe, the elongated photovoltaic cell strip arranged in the same direction as the water pipe, the load-bearing cable, and the irrigation sprinkler are combined together to form an elongated water-pipe photovoltaic module that can generate electricity by receiving sunlight and irrigate farmland by spraying water, and the two ends of the elongated water-pipe photovoltaic module are hung on the high-rise support;

[0009] ③the shadow of the water-pipe photovoltaic module projected on the ground surface, including the horizontal projection; wherein the ratio of the width D of the water-pipe photovoltaic module to the horizontal projection distance K of the water-pipe photovoltaic module, i.e. the shading coefficient D / K, is less than a set coefficient value, and the interval-height ratio K / H is less than a set coefficient value.

[0010] More preferably, the water-pipe photovoltaic system is characterized in that the midday shadow of the water-pipe photovoltaic module moves a distance of one midday shadow width every 1-20 minutes or every 1-5 minutes; or the midday shadow of the water-pipe photovoltaic module moves a distance of one midday shadow width for no more than 30 minutes or 1 hour, so as to avoid weakening the photosynthesis of the crops at that position and reducing the yield; for the purpose of unified detection standard, the midday shadow is defined as the shadow of the water-pipe photovoltaic module projected on the ground surface by the sun at noon (i.e. from 11:00 to 13:00).

[0011] More preferably, the water-pipe photovoltaic system is characterized in that the height H of the water-pipe photovoltaic module is increased, the shading coefficient D / K is reduced, and the interval-height ratio K / H is increased, so that the shadows of the adjacent water-pipe photovoltaic modules continuously block, release, block again, and release again to intermittently illuminate the crops (as the sun moves); so that the crops receive sunlight at a high frequency, for a long time, and intermittently every day, so as to stimulate the growth of the crops and improve the yield of the crops.

[0012] The research shows that making H≥3m, D≤415mm, shading coefficient D / K≤0.25, interval height ratio K / H≤1, and the sunlight required by crops is blocked for 3-5 minutes every 20 minutes; such intermittent blocking, releasing, blocking again, and releasing again of the sunlight of the same crop can stimulate the growth of crops and increase the yield of crops. In this way, the average sunlight absorbed by crops will be reduced by 13-20%. One set of data shows that the reduction of sunlight within 13% (equivalent to D / K≤0.15) has no effect on the photosynthesis and yield of crops; another set of data shows that the reduction of sunlight by more than 20% (equivalent to D / K≥0.25) begins to have some effect on the photosynthesis and yield of crops. Therefore, H≥3m, D≤415mm (235mm is the best), D / K≤0.25, interval height ratio K / H≤1, and each noon shadow moving 1D distance every 1-20 minutes are the golden ratio that does not hinder the photosynthesis of crops and have universal value.

[0013] The research shows that the length of time the shadow stays on the same crop is also inversely proportional to H and proportional to D. Taking Xinying District of Haikou City as an example, the shadow moving speed of the water pipe photovoltaic component with a height of 50 meters in the north-south direction at noon (11 o'clock) on March 4 is 68 cm / minute; if the height H of the water pipe photovoltaic component is reduced to 4.6 meters, the shadow moving speed will be reduced to 2.5 cm / minute, and if the height H of the water pipe photovoltaic component is reduced to 1.2 meters, the shadow moving speed will be reduced to 0.6 cm / minute. At noon (1:30 pm) on March 4, the height H of the water pipe photovoltaic component is reduced to 5 meters, and the shadow moving speed will be reduced to 1.3 cm / minute. Comparative observation at the same period shows that the shadow (southward) of the water pipe photovoltaic component with a height of 5 meters in the east-west direction moves at a speed of only 0.33 mm / minute, which is too slow, and in specific implementation, it is recommended to erect the relatively wide water pipe photovoltaic component along the north-south direction as much as possible. As can be seen, in order to reduce the impact of slow shadow moving speed on crop growth, the hanging height H of the water pipe photovoltaic component should be increased as much as possible. Given that the height H of 1 meter, the shadow stays on the crops for a long time (more than 1 hour on average), which will seriously affect the growth of crops, and therefore it is not recommended to use such a low height H; in order to reduce the impact of slow shadow moving speed on crop growth, the width D of the water pipe photovoltaic component should be reduced as much as possible.

[0014] In summary, in specific implementation, the height H should be preferably more than 3m, and more preferably more than 4.2m; the width D should be preferably less than or equal to 0.415m; the horizontal projection interval K should be preferably more than or equal to 0.5m, and more preferably more than or equal to 1m; D / K≤0.25, and more preferably D / K≤0.15.

[0015] In the implementation, the shading coefficient D / K should be selected according to the type of crops in the farmland. For crops that need shading nets to adjust the light level, and forest land that does not care about yield, such as vegetable crops like lettuce, spinach, kale, mustard, celery, green forest, grassland, etc., the shading coefficient D / K can be appropriately increased, the spacing K can be reduced, and the width D can be increased.

[0016] It is also preferred that the trench photovoltaic system is characterized in that: a photovoltaic cell layer and a transparent protective layer are arranged outside the water pipe, and irrigation / cooling water flows in the water pipe. In other words, the water pipe photovoltaic assembly is a tubular photovoltaic assembly with a photovoltaic cell layer wrapped outside the water pipe.

[0017] It is also preferred that the trench photovoltaic system is characterized in that: the water pipe and the (cylindrical or planar) photovoltaic cell (elongated) strip arranged in the same direction, as well as the (preferably one or two) load-bearing cables, and the irrigation sprinkler and other components, are combined together to form an elongated water pipe photovoltaic assembly that can generate electricity by receiving sunlight and irrigate farmland (and can be evenly sprayed like artificial rainfall), and is hung on high supports at both ends.

[0018] It is desirable that the trench photovoltaic system is characterized in that: the position of the irrigation sprinkler is higher than that of the water pipe photovoltaic assembly, and the water sprayed wetens / washes the transparent protective layer of the photovoltaic cell to cool and clean it, thereby improving the power generation efficiency.

[0019] The load-bearing cable referred to in this application generally refers to a linear object that can support the photovoltaic cell panel through tension, including ropes, steel cables, chains, linear objects formed by hooking multiple rod bodies or pipe bodies or profiles, etc.

[0020] Compared with the prior art, the application has the following beneficial technical effects.

[0021] Firstly, ingenious combination: the core of the trench photovoltaic system is its unique innovative concept of ingeniously combining the photovoltaic power generation system with the agricultural irrigation system, so that they share space, load-bearing cables, supports, and are constructed at one time, conveniently cooled and cleaned, forming a new energy production mode. While achieving precise and efficient irrigation, solar power generation can be collected, thereby forming a dual technical effect of irrigation and power generation, and the agricultural income from photovoltaic power generation can be used to compensate for agriculture, providing irrigation, fertilization, and pesticide services for agriculture.

[0022] Secondly, harmonious coexistence: the shading rate of the trench photovoltaic system can be strictly controlled within a predetermined range, which can ensure that the vegetation below can normally carry out photosynthesis, realizing the harmonious coexistence of photovoltaic power generation and ecological protection.

[0023] Thirdly, it does not occupy land: compared with traditional photovoltaic power station systems, the sky trench photovoltaic system only uses the space above farmland or forest, does not occupy the actual land area, avoids the occupation and damage of farmland resources, and guarantees food safety and ecological safety.

[0024] Fourthly, it generates electricity nearby: the sky trench photovoltaic system can be constructed nearby in the central and eastern regions, reducing the demand for long-distance power transmission, reducing power transmission loss and cost, and improving energy utilization efficiency. It not only solves the contradiction between photovoltaic power generation and land use, but also provides a new solution for the optimization of energy structure and the protection of ecological environment in the central and eastern regions.

[0025] Fifthly, intermittent light, increased yield and income: because the water pipe photovoltaic component can be arranged in the north-south direction, and can be very thin and high, and the interval-height ratio K / H can be very small, the shadows of adjacent multiple water pipe photovoltaic components can (without power / automatically by manual) block the sunlight in turn as the sun moves, so that the crops can obtain intermittent light, thereby stimulating the growth of crops and improving crop yield. In this way, not only does it not affect photosynthesis, but it also promotes crop growth and yield. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is an application schematic diagram of the sky trench photovoltaic system of the present application (embodiment one) above the farmland.

[0027] Figure 2 It is a horizontal projection cross-sectional structure schematic diagram of the water pipe photovoltaic component in Figure 1

[0028] It is a structure schematic diagram of a section of the water pipe photovoltaic component in Figure 3 Figure 1 It is a cross-sectional structure schematic diagram of the water pipe photovoltaic component in

[0029] Figure 4 Figure 3 It is a structure schematic diagram of a section of the water pipe photovoltaic component in

[0030] Figure 5 It is a structure schematic diagram of a section of the water pipe photovoltaic component in the present application (embodiment two).

[0031] Figure 6 It is another structure schematic diagram of a section of the water pipe photovoltaic component in the present application (embodiment three).

[0032] Figure 7 It is an external shape schematic diagram of a section of the water pipe photovoltaic component in the present application, which is covered with an arc-shaped photovoltaic cell layer outside the water pipe.

[0033] Figure 8 It is a cross-sectional structure schematic diagram of the water pipe photovoltaic component in Figure 7

[0034] ​​​Figure 9 This is a schematic diagram of the cross-sectional structure of a water pipe photovoltaic module with a flat photovoltaic cell layer covering the outer layer of another type of water pipe.

[0035] Figure 10 This is a schematic diagram of the cross-sectional structure of a water pipe photovoltaic module with a flat photovoltaic cell layer covering the outer layer of the water pipe.

[0036] Explanation of the reference numerals: 1-Water pipe photovoltaic module, 2-Bearing cable, 3-Photovoltaic cell, 4-Transparent protective layer, 5-Thickening layer, 6-Tall support, 601-Support beam (or support cable), 7-Crop, 8-Farmland, 9-Shadow, 10-Water pipe, 11-Spraying water, 12-Hanging component, 13-Light rays, 14-Sun, 15-Agricultural machinery, 16-Rinse strip. Detailed Implementation

[0037] To make the technical means, creative features, objectives and effects of this application easier to understand, the following describes this application in conjunction with specific implementation methods.

[0038] In the description of this application, it should be noted that the terms "upper," "lower," "left," "right," and "horizontal," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. It should also be noted that, for ease of description, this application defines the length direction of the water pipe photovoltaic module as longitudinal, and the direction perpendicular to it as transverse or left-right.

[0039] It should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "communication" should be interpreted broadly. For example, "communication" can refer to electrical connection or direct connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Example

[0040] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 7 , Figure 8 , Figure 9 As shown, thousands of photovoltaic modules 1, with water pipes spaced 1-2 meters apart and 3-15 meters above the ground, are erected above a farmland 8 (such as a wheat field, vegetable field, corn field, or orchard) in a north-south direction.

[0041] First, a photovoltaic cell 3 is wrapped around a (preferably high tensile strength of more than 1200 megapascal) steel strand type load bearing cable 2 and irrigation water pipe 10, such as a φ15.2x3 galvanized prestressed steel strand, high-strength fiber rope, carbon fiber cable, aramid cable, glass fiber cable, steel wire rope, lightweight pipe material, etc. (special) load bearing cable 2 and irrigation water pipe 10, wrap a circle (in other words, in the 360° angle range around the load bearing cable 2, lay a layer of photovoltaic cells composed of a large number of photovoltaic cells) photovoltaic cell 3, preferably using thin film photovoltaic cells as photovoltaic cells 3, to make a kind of (a load bearing cable 2 and an irrigation water pipe) water pipe photovoltaic module 1. Thin film photovoltaic cells (also known as thin film solar cells) are very flexible photovoltaic cells that can be cut into various shapes and sizes. Common shapes include long strips, circles, and even complex curved shapes. Patents "Thin film battery module, perovskite battery module and photovoltaic system (CN117295349A)", and CIGS thin film solar cells have been mass produced and are mature commercial products, which will not be described here. In specific implementation, it can be ordered from the manufacturer. It is worth looking forward to that Nature has published the latest research results "high toughness high power solar cell thinner than A4 paper" has been made. The battery can be arbitrarily rolled, especially suitable for packaging the water pipe photovoltaic module 1 in the invention, and can be ordered from the manufacturer in specific implementation.

[0042] Second, a transparent protective layer 4 is provided on the photovoltaic cell 3 layer. For example, a transparent protective layer 4 is made of polytetrafluoroethylene material, such as a transparent outer cover. Polytetrafluoroethylene material has excellent properties such as corrosion resistance, wear resistance, toughness, etc. It not only protects the photovoltaic cell module and receives light, but also has flexibility and can be bent, which helps to realize the bending of the battery module. This polytetrafluoroethylene film is also a mature commercial product, which will not be described here. When needed, it can be ordered or purchased from the relevant manufacturer.

[0043] Third, referring to the current cable production process of 100mm thick, a (cylindrical) battery module with a width size of D (i.e. diameter D is 100mm) and all cylindrical surfaces can accept light, regardless of how the water pipe photovoltaic module 1 is shaken (how to twist, how to shake, how to move), there is always a photovoltaic cell 3 layer facing the sun 14 to accept light and generate electricity, that is, a (circular) cylindrical battery module. In this way, it is packaged into a cable-shaped water pipe photovoltaic module 1 with a water pipe; the water pipe photovoltaic module 1 at least includes a (special) load bearing cable 2 and a photovoltaic cell 3 layer and a transparent protective layer 4 around the (special) load bearing cable 2. It does not have the problem that the water pipe photovoltaic module 1 moves and causes the sunlight incident angle to change. The cross section of the water pipe photovoltaic module 1 is preferably as follows Figure 4 or Figure 8the cross section can also be (but not recommended) an ellipse, a triangle, a square, a round tube + inclined / flat bar shape (as shown in Figure 9 or Figure 10 shown), a polygon close to a circle, etc.; wherein D≤30mm or 50mm or 100mm or 200mm or 300mm or 415mm or any suitable width dimension; the optimal size D is 100mm to 200mm.

[0044] It is particularly noted here that research has found that only the water pipe photovoltaic assembly 1 with a cross section of a true circle (i.e. a true cylindrical surface cell assembly) emits electricity with the most stable output voltage and current, and will not produce unstable voltage and current fluctuations that follow when the water pipe photovoltaic assembly 1 is twisted and wind shaken (including fluctuations, oscillations, etc.) by the wind. The reason is that the light receiving amount of the cylindrical surface water pipe photovoltaic assembly 1 will not change greatly due to shaking and other movements. On the contrary, if the water pipe photovoltaic assembly 1 with a cross section of an ellipse, a triangle, a square, a flat plate, a polygon, etc. is used, the problem of the change of the angle of incidence of sunlight will occur when the water pipe photovoltaic assembly 1 is moved by the wind, and the electricity emitted will be accompanied by voltage and current fluctuations that follow the wind shaking (shaking, oscillation) of the water pipe photovoltaic assembly 1, which will inevitably be difficult to transport and use. Therefore, it is strongly recommended to use a water pipe photovoltaic assembly 1 with a cross section close to a true circle in specific implementation, and not to use a water pipe photovoltaic assembly 1 with a cross section of a non-true circle.

[0045] Of course, the water pipe photovoltaic assembly 1 with a cross section of a triangle, a square, a polygon, etc. is not completely unusable, and can still be used in some scenarios, such as when the span L is very small, e.g. 10-20m, etc. The inclination of a certain layer of photovoltaic cells 3 of the water pipe photovoltaic assembly 1 can be artificially set to the optimal inclination, so that it is not affected by the wind and changes, thereby being used for power generation in small span L scenarios. In other words, in large span L scenarios, it is impossible to artificially adjust and fix the orientation of the water pipe photovoltaic assembly 1, and it is not suitable to use a water pipe photovoltaic assembly 1 with a non-true circle shape.

[0046] On the other hand, the water pipe photovoltaic assembly 1 with a cross section of a true circle, even if the wind is very strong, will not form a torque on the water pipe photovoltaic assembly 1 because it is an axisymmetric structure, so it will only oscillate and shake at a low frequency. In this way, the water pipe photovoltaic assembly 1 will be very durable and can guarantee 25 years of non-fatigue, non-aging, and non-fracture, and the current emitted will be stable and good.

[0047] In contrast, the current cable structure flexible photovoltaic support technology is to support two-dimensional plane photovoltaic cell panel with two (special) bearing cables and a stabilizing cable. When the plane photovoltaic cell panel is subjected to wind force from all directions in the high altitude, it will inevitably form a torque, resulting in easy twisting, wind vibration, changes in sunlight incidence angle, and large instantaneous current fluctuation. In summary, only the water pipe photovoltaic assembly 1 with a cross section of a true circle can overcome the difficulties of high-altitude erection, high installation cost, difficult cleaning and maintenance, short service life, easy twisting / wind vibration, large power generation fluctuation, and the difficulty of low-cost exploitation of surplus solar energy resources in the air above farmland 8.

[0048] In the fourth step, the water pipe photovoltaic assemblies 1 prepared in the previous steps are arranged in the air above the farmland 8 by the high-rise support 6 (similar to the electric wire tower / rod) such as support column or hanging cable tower, and are hung in the air like the erection of high-voltage transmission lines, so as to form an array of water pipe photovoltaic assemblies 1. The height H of the water pipe photovoltaic assembly 1 from the ground surface can be set to 2 meters, the span L of the single span of the water pipe photovoltaic assembly 1 can be set to 200-300 meters, and the distance K between the horizontal projections of the water pipe photovoltaic assemblies 1 (in the farmland 8) is preferably set to 1-2 meters. For example, H can be greater than or equal to 5m or 10m. In summary, the height H should be high enough to ensure that the top of the crops 7 will not touch the water pipe photovoltaic assembly 1. L can be greater than or equal to 10m or 20m or 50m or 100m or 500m or 1000m. In summary, the span L should be large enough to reduce the number of high-rise supports 6, reduce the pile foundation area, and avoid serious interference with large agricultural machinery 15 operations. K is preferably greater than or equal to 1m or 2m or 3m or 5m or 10m. In summary, the width of the shadow 9 of the water pipe photovoltaic assembly 1 should be appropriately reduced, the light requirement for the growth of crops 7 should be minimally ensured, and the yield reduction due to insufficient light should be avoided.

[0049] In order to reduce the number of pile foundations such as support columns and save the ground surface area, and in order to ensure that the water pipe photovoltaic assembly 1 can be erected along the north-south direction, the support cross beam 601 in the high-rise support 6 can also not use a rigid cross beam, but a flexible cross beam, such as a very thick steel cable (not shown in the figure).

[0050] It should be noted that in the implementation, the width dimension D of the water pipe photovoltaic assembly 1 should be appropriately reduced, and the horizontal spacing K of the water pipe photovoltaic assembly 1 should be appropriately increased, so as to ensure that the ratio D / K of the width dimension D of the water pipe photovoltaic assembly 1 to the horizontal projection spacing K of the water pipe photovoltaic assembly 1 (in the farmland 8) is ≤0.01 or 0.02 or 0.03 or 0.05 or 0.10 or 0.20 or 0.30 or 0.5 or 1 or 2 or 3, so that the shadow 9 of the same water pipe photovoltaic assembly 1 quickly (for example, within 5 minutes) moves across the same plant 7 (preferably moving a distance of 1 width dimension D within 5 minutes) as the sun 14 moves, so as to avoid the same plant 7 staying in the shadow 9 of the same water pipe photovoltaic assembly 1 for a long time (for example, more than 30 minutes) to reduce photosynthesis and cause the plant 7 to reduce yield. Research has found that the length of time that the shadow 9 stays on (i.e., covers) the same plant 7 is inversely proportional to H and proportional to D. Therefore, in order to reduce the impact of the shadow 9 and uneven light on the growth of the plant 7, the hanging height of the water pipe photovoltaic assembly 1 should be as high as possible, and the width dimension of the water pipe photovoltaic assembly 1 should be as small as possible. Preferably, H is selected to be 3-5m, and the width dimension D is selected to be 10-20cm.

[0051] Preferably, in order to ensure that the horizontal projection (i.e., the shadow 9) of the water pipe photovoltaic assembly 1 in the farmland 8 has a relatively small spacing K between them, while avoiding mutual collision when a strong wind blows and causes them to swing left and right, a three-dimensional erection method with high and low staggering can be adopted to stagger them with each other.

[0052] It is also preferred that, in order to set a layer of photovoltaic cells 3 with the largest possible area in a unit length of the water pipe photovoltaic assembly 1 to reduce the cost of kilowatt-hour, some thickening fillers 5 (for example, fillers with good thermal conductivity) can be filled between the (dedicated) load-bearing cable 2 and the layer of photovoltaic cells 3, so as to increase the thickness dimension of the water pipe photovoltaic assembly 1 and expand the settable area of the layer of photovoltaic cells 3, thereby greatly increasing the light receiving area per unit length of the water pipe photovoltaic assembly 1 and reducing the power generation cost per unit length.

[0053] It is gratifying that the flowing water in the water pipe 10 will take away the heat of the photovoltaic cells 3 to cool them down, thereby conveniently improving the power generation efficiency. Embodiment

[0054] As Figure 5As shown, the irrigation water pipe 10 of the water pipe photovoltaic module 1 in Example 1 is externally placed. The irrigation water pipe 10 is suspended from a load-bearing cable 2 by a hanger 12, and cylindrical photovoltaic cell modules 3 are strung on the load-bearing cable 2. In this way, a cylindrical water pipe photovoltaic module 1 is formed. It is then suspended horizontally over the farmland 8 by tall support structures 6 (similar to power line towers / poles) with a height of 3-15 meters, arranged at intervals like high-voltage power lines, to form an array of water pipe photovoltaic modules 1 with the same effect as in the example above. Example

[0055] like Figure 6 As shown, the irrigation water pipe 10 of the water pipe photovoltaic module 1 in Examples 1 and 2 above is externally placed. The irrigation water pipe 10 is suspended from a load-bearing cable 2 by a hanging device 12, and some slender strip photovoltaic cell modules 3 are suspended from the load-bearing cable 2. In this way, a slender strip water pipe photovoltaic module 1 is formed. It is then suspended horizontally over the farmland 8 by a tall support structure 6 (similar to a power line tower / pole) with a support column or cable tower (3-15 meters high) at intervals, like a high-voltage power transmission line, to form another water pipe photovoltaic module 1 array with the same effect as Examples 1 and 2 above.

[0056] It is preferable to position the irrigation nozzle higher than the water pipe photovoltaic module so that the water 11 sprayed from the water pipe photovoltaic module 1 can also wet or wash the transparent protective layer 4 of the slender photovoltaic cell 3, cooling and cleaning it, thereby improving power generation efficiency.

[0057] The above-disclosed embodiments are merely preferred embodiments of this application. The accompanying drawings are only schematic diagrams and are not drawn to scale. They cannot be used to limit the scope of this application. Equivalent variations made based on the claims of this application still fall within the scope of this application.

Claims

1. An underdrain photovoltaic system characterized in that it Comprise: ① a water pipe and a photovoltaic cell assembly for power generation, combined into an elongated water pipe photovoltaic assembly that can both receive sunlight for power generation and deliver water for irrigation to farmland; ② a high-rise support and an array of water pipe photovoltaic assemblies suspended by load-bearing cables at intervals above farmland; the width of the water pipe photovoltaic assembly is D, the height is H, the span is L, and the horizontal projection spacing is K, where D is less than the set width size, H is greater than the set height size, L is greater than the set span size, and K is greater than the set spacing size; the water pipe, the elongated photovoltaic cell assembly arranged in the same direction, the load-bearing cable, and the irrigation sprinkler are combined into an elongated water pipe photovoltaic assembly that can both receive sunlight for power generation and deliver water for irrigation to farmland, with both ends hanging on the high-rise support; ③ the shadow cast on the ground by the water pipe photovoltaic assembly, including the horizontal projection; the ratio of the width D of the water pipe photovoltaic assembly to the spacing K of its horizontal projection, the shading coefficient D / K, is less than the set coefficient value.

2. The underfloor photovoltaic system according to claim 1, characterized by: The outer layer of the water pipe is covered with a photovoltaic cell layer and a transparent protective layer, and the water pipe flows with irrigation / cooling water.

3. The underfloor photovoltaic system according to claim 1, characterized by: The position of the irrigation sprinkler is higher than that of the water pipe photovoltaic assembly, and the water sprayed wetens / washes the transparent protective layer of the photovoltaic cell.

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