JP7599188B2 - Photovoltaic power generation system - Google Patents

Description

This disclosure relates to a solar power generation system.

Patent Document 1 describes a solar power generation system that includes a first solar panel unit having an actuator unit, a second solar panel unit without an actuator unit, and a control unit. A detection signal from a water temperature sensor and a detection signal from an air temperature sensor are input to the control unit. The control unit detects the water temperature based on the detection signal from the water temperature sensor, and detects the air temperature based on the detection signal from the air temperature sensor. The control unit controls the actuator unit according to the detected water temperature and air temperature, and the controlled actuator unit controls the amount of solar radiation on the farmland by swinging the solar panel.

Patent Document 2 describes solar panels installed on farmland. The solar panels are installed at a specified angle to the farmland so that they receive sunlight most efficiently. Crops are grown in areas of the farmland where the solar panels block the sunlight. Sunlight is reflected by the ground and the underside of the solar panel, and the light reflected by the underside of the solar panel is irradiated onto the crops.

Patent document 3 describes a solar power generation facility in which multiple arrays are installed above farmland. The arrays include modules with set light receiving angles. The solar power generation facility controls shading of the farmland. The arrays are long and narrow rectangular. The narrow width of the arrays makes it possible to avoid shading a portion of the farmland for a long period of time and to generate shadows evenly across the farmland.

Patent Document 4 describes multiple solar power generation devices installed in rice fields. The solar power generation device includes a solar panel, a stand supporting the solar panel, a linear actuator, a rotary actuator, a light sensor, and a controller. The linear actuator and rotary actuator tilt the solar panel so that the light receiving surface of the solar panel faces the position of the sun detected by the light sensor. The solar panel is provided with multiple solar modules and multiple openings. By allowing sunlight to pass below the solar panel through the multiple openings, it is possible to reduce areas that are shaded for long periods of time.

JP 2016-67272 A JP 2014-18082 A JP 2011-129852 A JP 2018-98999 A

Each of the solar power generation systems mentioned above can provide sufficient sunlight to agricultural crops and reduce areas of shade on agricultural land. However, in agricultural land, particularly in the summer, rising temperatures can cause high-temperature damage to agricultural crops. When high-temperature damage occurs, the crops may wither and the yield of the crops may decrease.

The present disclosure aims to provide a solar power generation system that can increase agricultural crop yields.

The solar power generation system according to the present disclosure is a solar power generation system equipped with solar panels installed above farmland. The solar power generation system includes a high temperature damage determination unit that determines whether high temperature damage will occur to crops grown on the farmland based on the temperature of the farmland, a panel adjuster that operates the solar panel to adjust the size of the shadow on the farmland, a brightness detection unit that detects whether it is nighttime or not, and a control unit that controls the adjustment of the size of the shadow by the panel adjuster. When the high temperature damage determination unit determines that high temperature damage will occur and the brightness detection unit determines that it is not nighttime, the control unit controls the panel adjuster to operate the solar panel so as to increase the area of the shadow formed on the farmland. When the high temperature damage determination unit determines that high temperature damage will occur and the brightness detection unit determines that it is nighttime, the control unit controls the panel adjuster to tilt the solar panel so as to promote radiative cooling in the farmland.

This solar power generation system includes a high temperature damage determination unit that determines whether high temperature damage will occur to the crops grown on the farmland based on the temperature of the farmland, and a brightness detection unit that detects whether the farmland is at night. The solar power generation system includes a control unit that controls the adjustment of the size of the shadow by the panel regulator. When it is determined that high temperature damage will occur and the brightness detection unit determines that the farmland is not at night, the control unit operates the solar panel to increase the area of the shadow formed on the farmland. Therefore, when it is determined that high temperature damage will occur and the farmland is not at night, the area of the shade on the farmland increases, so that high temperature damage to the crops on the farmland can be suppressed. When it is determined that high temperature damage will occur and the brightness detection unit determines that the farmland is at night, the control unit tilts the solar panel to promote radiative cooling in the farmland. By promoting radiative cooling in the farmland, it is possible to suppress the accumulation of hot air in the farmland at night, so that the occurrence of high temperature damage at night can be suppressed. Therefore, since the occurrence of high temperature damage can be suppressed not only during the day but also at night, it is possible to increase the yield of agricultural crops while collecting electricity with the solar panel.

The solar power generation system may include a water sprinkler nozzle that sprinkles water on farmland. When the high temperature damage determination unit determines that high temperature damage will occur, the control unit may control the water sprinkler nozzle to sprinkle water on the farmland from the water sprinkler nozzle. In this case, water is sprinkled on the farmland from the water sprinkler nozzle when it is determined that high temperature damage will occur, so that high temperature damage to agricultural crops can be suppressed even when temperatures are high.

The solar power generation system may include a pesticide fertilizer spraying nozzle that spreads pesticide fertilizer on farmland. When the high temperature damage determination unit determines that high temperature damage will occur, the control unit may control the pesticide fertilizer spraying nozzle to spray the pesticide fertilizer on the farmland from the pesticide fertilizer spraying nozzle. In this case, since the pesticide fertilizer is sprayed from the pesticide fertilizer spraying nozzle when it is determined that high temperature damage will occur, it is possible to prevent agricultural crops from withering due to high temperature damage.

The solar power generation system may be equipped with a wind meter that measures wind volume and direction on farmland. When the wind volume measured by the wind meter is equal to or greater than a wind volume threshold, the control unit may control the panel adjuster to tilt the solar panel so that the sunlight receiving surface of the solar panel is parallel to the wind direction measured by the wind meter. In this case, when the wind volume is equal to or greater than the wind volume threshold, the solar panel is tilted so that the light receiving surface of the solar panel is parallel to the wind direction at that time. Therefore, when the wind is strong, the solar panel is tilted so that the light receiving surface of the solar panel is parallel to the wind direction, thereby suppressing an increase in wind stress on the solar panel.

The solar power generation system may include a blower that blows air into the farmland. The control unit may control the blower to blow air into the farmland when the high temperature damage determination unit determines that high temperature damage will occur. In this case, air is blown into the farmland from the blower when it is determined that high temperature damage will occur, thereby preventing high temperature damage from occurring to crops in the farmland.

This disclosure makes it possible to increase crop yields.

FIG. 2 is a side view illustrating farmland to which the solar power generation system according to the embodiment is applied. 1 is a functional block diagram of a solar power generation system according to an embodiment. FIG. FIG. 13 is a diagram illustrating an example of a table of shadow information. 13 is a diagram showing an example of a high temperature damage determination table used by a high temperature damage determination unit; FIG. 13A, 13B, and 13C are diagrams illustrating modified examples of the solar panel. FIG. 2 is a diagram illustrating a nozzle unit of the solar power generation system according to the embodiment. 4 is a flowchart illustrating an example of steps of a high temperature damage suppression method according to an embodiment.

Below, an embodiment of a solar power generation system according to the present disclosure will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are given the same symbols, and duplicate descriptions will be omitted as appropriate. The drawings are partially simplified or exaggerated for ease of understanding, and the dimensional ratios, etc. are not limited to those shown in the drawings.

Figure 1 is a side view showing a schematic diagram of a solar power generation system 1 according to an embodiment. As shown in Figure 1, in the solar power generation system 1, solar panels P consisting of multiple solar modules are arranged above farmland N, and each solar panel P generates solar power. The solar panel P has, for example, a rectangular shape. The solar panel P has a light receiving surface P1 that receives sunlight L from the sun T. When the solar panel P receives sunlight L on the light receiving surface P1, it generates power according to the amount of light received.

For example, multiple crops C of the same type are planted in farmland N, and multiple crops C are cultivated in farmland N. As an example, the crops C are rice, and the farmland N is a rice field. In the solar power generation system 1, the number of solar panels P is, for example, several hundred, and multiple solar panels P are arranged vertically and horizontally in a plan view. Therefore, sunlight L from the sun T is directed onto the crops C in the farmland N, and a shadow S is formed on the farmland N. As an example, when multiple solar panels P extend horizontally, the shading rate of sunlight L on the farmland N is 40%. However, the shape and size of the shadow S changes as the sun T moves over time.

The solar power generation system 1 comprises a support structure 2 that supports multiple solar panels P above farmland N. Each solar panel P is installed on the support structure 2 above the farmland N. The support structure 2 comprises multiple pillars 2b extending upward from the farmland N, and beam members 2c that span the multiple pillars 2b at the top of the multiple pillars 2b. Multiple shafts 3 are attached to the beam members 2c, and a solar panel P is supported on each shaft 3 so that it can rotate freely.

For example, the height of the solar panel P with respect to the ground is 3 m or more and 4 m or less (3.5 m as an example). The solar panel P rotates with the rotation of the axis 3, and for example, the inclination angle θ of the light receiving surface P1 of the solar panel P with respect to the incident direction of the sunlight L is uniform. In this case, the solar power generation system 1 has a configuration in which the solar panel P rotates on a single axis, and the inclination angle θ of the solar panel P is adjustable.

2 is a block diagram showing the functions of the solar power generation system 1. As shown in FIGS. 1 and 2, the solar power generation system 1 includes a panel adjuster 4 that operates the solar panel P to adjust the size of the shadow S falling on the farmland N, an actinometer 5 that measures the amount of solar radiation D1 of sunlight L on the farmland N, and a thermometer 6 that measures the temperature D2 of the farmland N. The solar power generation system 1 further includes a wind gauge 7 that measures the wind volume D3 and wind direction D4 on the farmland N, a brightness detector 8 that detects whether it is nighttime on the farmland N, and a controller 10 that controls each part of the solar power generation system 1. Each of the panel adjuster 4, the actinometer 5, the thermometer 6, the wind gauge 7, and the brightness detector 8 is capable of communicating with the controller 10.

The panel adjuster 4 includes, for example, a motor that rotates the shaft 3. The panel adjuster 4 rotates the solar panel P uniformly by rotating the shaft 3. The tilt angle θ is variable by the panel adjuster 4 rotating the solar panel P, and by varying the tilt angle θ, the area of the shadow S on the farmland N can be adjusted. For example, when the tilt angle θ is equal to or greater than a certain value, the ratio of the area of the shadow S to the area of the farmland N is higher than when the tilt angle θ is less than the certain value.

The actinometer 5 is a sensor that detects the amount of solar radiation D1 of sunlight L irradiating the farmland N, and outputs the detected amount of solar radiation D1 to the controller 10. The thermometer 6 is a sensor that detects the air temperature D2 of the farmland N, and outputs the detected air temperature D2 to the controller 10. The timing at which the actinometer 5 outputs the amount of solar radiation D1 to the controller 10, and the timing at which the thermometer 6 outputs the air temperature D2 to the controller 10 may be in real time or at predetermined intervals.

The wind measuring device 7 includes, for example, an anemometer. The wind measuring device 7 measures the wind volume D3 in the farmland N and outputs the measured wind volume D3 to the controller 10. The wind measuring device 7 measures the wind direction D4 in the farmland N and outputs the measured wind direction D4 to the controller 10. The wind measuring device 7 may be an anemometer. As an example, the wind measuring device 7 is a propeller type anemometer. However, the wind measuring device 7 may be something other than a propeller type anemometer, and may be a thermal anemometer, a cup anemometer, or an ultrasonic anemometer.

The brightness detection unit 8 detects whether it is nighttime on the farmland N from the brightness of the farmland N. For example, the brightness detection unit 8 has a light receiving element that receives light in the farmland N, and a judgment unit that judges whether it is nighttime on the farmland N. The judgment unit of the brightness detection unit 8 judges whether it is nighttime on the farmland N from the amount of light received by the light receiving element of the brightness detection unit 8. The result of the judgment of whether it is nighttime by the judgment unit of the brightness detection unit 8 is output to the controller 10.

The controller 10 has a control unit 11 that controls the panel adjuster 4. The control unit 11 drives the panel adjuster 4 to adjust the tilt angle θ of the solar panel P. The control unit 11 changes the tilt angle θ of the solar panel P to adjust the amount of sunlight L entering the farmland N and adjust the ratio of the area of shadow S to the total area of the farmland N. In this way, the control unit 11 adjusts the amount of sunlight L and changes the ratio of the area of shadow S, thereby preventing the growth of the crops C on the farmland N from being hindered.

The controller 10 is configured to include, for example, a CPU (Central Processing Unit) and a storage unit such as a ROM (Read Only Memory) or a RAM (Random Access Memory). Each function of the controller 10 is realized, for example, by loading a program stored in the ROM into the RAM and executing the program by the CPU.

The controller 10 may be, for example, a general-purpose personal computer, a server on the Internet, or a cloud system. Furthermore, a part of the controller 10 may be separated from the remainder. The controller 10 may be provided near the farmland N, or may be provided in a remote location away from the farmland N. The controller 10 is connected to a network 20, for example, the Internet. The network 20 does not have to be the Internet, and may be, for example, an in-facility network (intranet). For example, a part of the controller 10 may be disposed near the solar panel P, and the remainder of the controller 10 may be disposed in a remote location away from the solar panel P. In this way, the form and location of the controller 10 are not particularly limited.

For example, the controller 10 has a database 12 that stores information about the solar power generation system 1. The database 12 stores information used by the control unit 11 when adjusting the tilt angle θ of the solar panel P. The database 12 stores a date D5, a time D6, a trajectory D7, and shadow information D8. The trajectory D7 is information indicating the trajectory of the sun T as seen from the farmland N, and is stored for each date D5. The trajectory D7 indicates the position (height and direction) of the sun T at regular intervals (e.g., every minute) in a day, and varies according to the date D5. This trajectory D7 makes it possible to know what time of day and to what extent a shadow S is formed.

Shadow information D8 is information indicating the ratio of the area of shadow S to the area of farmland N. For example, as shown in FIG. 3, shadow information D8 has table Z indicating the relationship between the inclination angle θ and the ratio of shadow S of farmland N. Shadow information D8 may be information indicating the ratio of shadow S to which part of farmland N. Shadow information D8 is information indicating, for example, the ratio of shadow S of farmland N for each inclination angle θ. Shadow information D8 may also be information indicating the ratio of shadow S of farmland N for each date D5, each time D6, and each inclination angle θ.

As shown in Figures 1 and 2, database 12 stores crop D9 indicating the type of crop C cultivated on farmland N. Furthermore, database 12 is a light saturation point memory section that stores the light saturation point (unit: klx (kilolux)) D10 of crop C. The light saturation point D10 is stored for each crop D9. The light saturation point D10 is a value that is uniquely determined for each type of crop D9, and even if sunlight L at or above the light saturation point D10 is applied to crop C, the amount of photosynthesis of crop C does not increase.

The database 12 functions as a solar radiation acquisition unit that acquires the amount of solar radiation D1 for the farmland N from the actinometer 5, and stores the acquired amount of solar radiation D1. The database 12 may also acquire the amount of solar radiation D1 for each date D5 or each time D6 in advance, rather than acquiring the amount of solar radiation D1 from the actinometer 5 each time. Furthermore, the controller 10 may calculate the amount of solar radiation D1 from the date D5, the time D6, and meteorological information D11 described below, and the database 12 may acquire the amount of solar radiation D1 calculated by the controller 10.

The database 12 is a temperature acquisition unit that acquires the temperature D2 of the farmland N from the thermometer 6, and stores the acquired temperature D2. Note that the database 12 may not acquire the temperature D2 from the thermometer 6, but may instead store in advance the temperature D2 acquired from the weather information D11, for example. The controller 10 may also estimate the temperature D2 from the date D5 and time D6, and the database 12 may acquire the temperature D2 estimated by the controller 10.

The database 12 is a wind volume acquisition unit that acquires the wind volume D3 of the wind blowing from the wind measurement device 7 into the farmland N. The database 12 is also a wind direction acquisition unit that acquires the wind direction D4 of the wind blowing from the wind measurement device 7 into the farmland N. As above, the database 12 may store in advance the wind volume D3 and wind direction D4 obtained from the weather information D11. The controller 10 may also estimate the wind volume D3 and wind direction D4 after a certain time has elapsed from the wind state measured by the wind measurement device 7, and the database 12 may acquire the wind volume D3 and wind direction D4 estimated by the controller 10.

The database 12 is a weather information acquisition unit that acquires weather information D11 from the network 20. The timing of acquisition of the weather information D11 by the database 12 may be in real time or at regular intervals. Furthermore, the database 12 stores the amount of power generation D12 obtained from the solar panel P.

The control unit 11 is an angle change unit that outputs a control signal to the panel adjuster 4 to control the operation of the panel adjuster 4 and change the tilt angle θ of the solar panel P. The control unit 11 has the function of performing various calculations. For example, the solar power generation system 1 may be equipped with multiple cameras that photograph farmland N, and the control unit 11 may calculate the ratio of the area of the shadow S to the area of the farmland N from images photographed by the multiple cameras. The ratio of the area of the shadow S calculated by the control unit 11 is stored in the database 12. The control unit 11 also controls the panel adjuster 4 using various information stored in the database 12 and changes the tilt angle θ of the solar panel P.

The control unit 11 may change the tilt angle θ of the solar panel P in accordance with the weather information D11 acquired by the database 12. For example, the controller 10 may be equipped with multiple control units 11, and weather information D11 may be sent from the database 12, which is located in a remote location away from the farmland N, to the multiple control units 11 to simultaneously control the tilt angles θ of the multiple solar panels P. In this case, optimal control of the solar panel P in accordance with the weather in the farmland N is possible.

As a specific example, in the event of heavy snowfall, the inclination angle of the solar panel P relative to the horizontal plane can be increased and the solar panel P can be set up vertically, thereby preventing snow from accumulating on the solar panel P. As a specific example, in the event of a typhoon, the inclination angle of the solar panel P relative to the horizontal plane can be decreased and the solar panel P can be laid horizontally, thereby preventing the solar panel P from being subjected to wind loads.

The controller 10 has, for example, a communication unit 14 and a high temperature damage determination unit 15. The communication unit 14 is, for example, a communication device used when the controller 10 communicates with devices other than the controller 10. The communication unit 14 enables the controller 10 to communicate with an information terminal 16 located outside the controller 10.
The information terminal 16 is, for example, a personal computer. However, the information terminal 16 may be an information terminal other than a personal computer, for example, a mobile terminal. A "mobile terminal" refers to a portable information terminal, for example, a mobile phone including a smartphone, a tablet, or a laptop computer. The tilt angle θ of the solar panel P can be adjusted by operating the controller 10 from the information terminal 16 located away from the farmland N via the communication unit 14.

For example, the controller 10 has a high temperature damage determination unit 15 that determines whether high temperature damage will occur to the crop C cultivated in the farmland N based on the air temperature D2 of the farmland N. In this disclosure, "high temperature damage" may include not only high temperature damage itself but also temperature damage in general. For example, the high temperature damage determination unit 15 determines that high temperature damage will occur to the crop C when the air temperature D2 of the farmland N is above a certain value for a certain period of time. The high temperature damage determination unit 15 has a high temperature damage determination table H that indicates the temperature threshold and time threshold that will cause high temperature damage for each type of crop C, as shown in FIG. 4, for example.

The temperature threshold indicates the temperature at which high temperature damage will occur to crop C. If the state where the temperature is equal to or higher than the temperature threshold continues for the time threshold or more, high temperature damage may occur to crop C. The high temperature damage determination unit 15 compares the temperature of farmland N with the temperature threshold in the high temperature damage determination table H and determines whether the time at which the temperature is equal to or higher than the temperature threshold continues for the time threshold or more. When the high temperature damage determination unit 15 determines that the temperature of farmland N is equal to or higher than the temperature threshold and that the state where the temperature is equal to or higher than the temperature threshold continues for the time threshold or more, it determines that high temperature damage will occur to crop C. For example, when the high temperature damage determination unit 15 determines that the temperature of farmland N has been equal to or higher than 34°C for 7 hours or more, it determines that high temperature damage will occur to crop A. When the high temperature damage determination unit 15 determines that the temperature of farmland N has been equal to or higher than 30°C for 12 hours or more, it determines that high temperature damage will occur to crop B.

1 and 2, when the high temperature damage determination unit 15 determines that a high temperature damage will occur and the brightness detection unit 8 determines that it is not nighttime (it is daytime), the control unit 11 controls the panel adjuster 4 to increase the area of the shadow S on the farmland N. For example, when the high temperature damage determination unit 15 determines that a high temperature damage will occur, the control unit 11 increases the tilt angle θ of the solar panel P to increase the area of the shadow S on the farmland N by N times (N is a positive real number). The value of N is, for example, 1.5 or more and 2.0 or less. When the high temperature damage determination unit 15 determines that a high temperature damage will not occur and the brightness detection unit 8 determines that it is not nighttime, the control unit 11 may control the panel adjuster 4 to reduce the area of the shadow S on the farmland N.

The above describes an example in which the control unit 11 increases the inclination angle θ of the solar panel P to increase the area of the shadow S of the farmland N. When the control unit 11 increases the inclination angle θ, it is possible to increase the area of the shadow S and the amount of power generated by the solar panel P. However, the method of increasing the area of the shadow S of the farmland N using a solar panel is not limited to the above example. Figures 5(a), 5(b), and 5(c) each show modified examples of a solar panel.

For example, as shown in Fig. 5(a), the area of the shadow S may be increased by using a solar panel Q having multiple cylinders Q1. The solar panel Q has an axis 3A, a pair of cylinders Q1 extending from the axis 3A, a pair of first plate-like members Q2 fixed to the opposite side of each cylinder Q1 from the axis 3A, and a second plate-like member Q3 that houses the axis 3A, the pair of cylinders Q1, and a part of the pair of first plate-like members Q2. Each cylinder Q1 expands and contracts when driven by a panel adjuster 4.

For example, the amount of protrusion of the first plate-shaped member Q2 relative to the second plate-shaped member Q3 is variable by extending and retracting the cylinder Q1. For example, when the high temperature damage determination unit 15 determines that a high temperature damage will occur, the control unit 11 may extend the cylinder Q1 to increase the amount of protrusion of the first plate-shaped member Q2 relative to the second plate-shaped member Q3, thereby increasing the area of the shadow S of the farmland N.

For example, as shown in FIG. 5(b), a sliding solar panel R may be used to increase the area of the shadow S. The solar panel R has an axis 3B, a first plate member R1 extending from the axis 3B, and a pair of second plate members R3 that slide relative to the main surface R2 of the first plate member R1. Each second plate member R3 is supported by the first plate member R1 via a respective one of a plurality of slide rails R4. In the solar panel R, the second plate member R3 slides relative to the first plate member R1, thereby varying the amount of protrusion of each second plate member R3 relative to the first plate member R1.

For example, when the high temperature damage determination unit 15 determines that a high temperature damage will occur, the control unit 11 may increase the area of the shadow S of the farmland N by sliding each second plate-shaped member R3 relative to the first plate-shaped member R1 to increase the amount of protrusion of each second plate-shaped member R3 relative to the first plate-shaped member R1. Also, in the example of Figure 5 (b), the second plate-shaped member R3 and the slide rail R4 are provided on the surface opposite the light receiving surface of the solar panel P. Therefore, the impact on the power generation of the solar panel P can be suppressed.

For example, as shown in FIG. 5(c), the area of the shadow S may be increased by using a solar panel X having a hinge mechanism X1. The solar panel X includes a pair of hinge mechanisms X1, a first plate-shaped member X2 including an axis 3C, and a pair of second plate-shaped members X3 supported by the first plate-shaped member X2 via each hinge mechanism X1. The pair of hinge mechanisms X1 are fixed to the surface of the first plate-shaped member X2 opposite the light receiving surface X5, and support each second plate-shaped member X3 rotatably relative to the first plate-shaped member X2. In this way, the pair of hinge mechanisms X1 and the pair of second plate-shaped members X3 are provided on the opposite side of the light receiving surface X5, thereby suppressing the effect of power generation on the solar panel P. The panel adjuster 4 controls the hinge mechanism X1 to change the angle Y of each second plate-shaped member X3 relative to the first plate-shaped member X2.

For example, the control unit 11 rotates each second plate-shaped member X3 to increase angle Y when the high temperature damage determination unit 15 determines that a high temperature damage will occur. For example, the control unit 11 may reduce the area of the portion of the solar panel X that receives the wind by decreasing angle Y when the air volume D3 measured by the wind meter 7 is equal to or greater than the air volume threshold. In this case, excessive stress due to the wind can be prevented from being applied to the solar panel X.

As shown in FIG. 1, for example, the solar power generation system 1 includes a blower 9. For example, a plurality of blowers 9 are provided in the farmland N, and each blower 9 is fixed to a support structure 2. For example, the blower 9 is disposed between a pair of solar panels P. As an example, each blower 9 is provided at the intersection of a support 2b and a beam member 2c. Wind W is blown downward (or diagonally downward) from the blower 9. The wind W from the blower 9 lowers the temperature of the farmland N, suppressing the occurrence of high-temperature damage to the crops C.

1 and 2, when the high temperature damage determination unit 15 determines that a high temperature damage will occur, the control unit 11 controls the blower 9 to send air (wind W) into the farmland N. For example, when the high temperature damage determination unit 15 determines that a high temperature damage will occur and the brightness detection unit 8 determines that it is nighttime, the control unit 11 controls the panel adjuster 4 to tilt the solar panel P so as to promote radiative cooling in the farmland N. Thus, at night, the solar panel P is tilted to release heat from the farmland N. That is, the panel adjuster 4 is controlled to tilt the solar panel P so that more heat is released from the farmland N. As an example, in order to reduce the area of the solar panel P located above the farmland N, the tilt of the solar panel P may be controlled by the panel adjuster 4 so that the light receiving surface P1 of the solar panel P extends along the vertical direction. In this case, it is possible to further promote radiative cooling in the farmland N. The control unit 11 may also tilt the solar panel P so that the light receiving surface P1 is parallel to the wind direction D4 measured by the wind measurement device 7. In this case, it is possible to allow more wind to penetrate into the farmland N.

When the high temperature damage determination unit 15 determines that a high temperature damage will occur and the brightness detection unit 8 determines that it is nighttime, the control unit 11 may control the blower 9 to blow wind W into the farmland N from the blower 9. In this case, it is also possible to allow more wind W to enter the farmland N. For example, when the wind volume D3 measured by the wind meter 7 is equal to or greater than the wind volume threshold, the control unit 11 controls the panel adjuster 4 to tilt the solar panel P so that the light receiving surface P1 of the solar panel P is parallel to the wind direction D4 measured by the wind meter 7. The wind volume threshold is a wind volume threshold at which the stress applied to the solar panel P by the wind becomes excessive and there is a possibility that the solar panel P will be damaged. In this embodiment, even if the solar panel P is installed at a high position of 3 m or more and 4 m or less, the stress on the solar panel P can be suppressed from becoming excessive.

For example, the solar power generation system 1 includes a nozzle unit 30 having a water spray nozzle 31 for spraying water on the farmland N, and a pesticide and fertilizer spray nozzle 32 for spraying pesticide and fertilizer on the farmland N. Figure 6 is a schematic diagram of the nozzle unit 30. As shown in Figures 1, 2 and 6, the solar power generation system 1 includes a plurality of nozzle units 30, and each nozzle unit 30 is fixed to the support structure 2. For example, each nozzle unit 30 is fixed to a beam member 2c. As an example, the nozzle unit 30 is arranged between a pair of solar panels P.

The nozzle unit 30 includes a water spray nozzle 31 and a pesticide/fertilizer spray nozzle 32. For example, the water spray nozzle 31 automatically sprays water E under the control of the control unit 11, and the pesticide/fertilizer spray nozzle 32 automatically sprays pesticide/fertilizer F under the control of the control unit 11. The water spray nozzle 31 is a nozzle that sprays water E on the farmland N. The pesticide/fertilizer spray nozzle 32 is a nozzle that sprays pesticide/fertilizer F on the farmland N. In this disclosure, "pesticide/fertilizer" refers to at least one of pesticides and fertilizers. "Pesticide" is a growth promoter or drug for crop C. "Fertilizer" refers to a substance that promotes the growth of crop C, and includes at least one of nitrogen, phosphorus, and potassium, for example. "Fertilizer" may be an inorganic fertilizer or an organic fertilizer. The type of pesticide/fertilizer F sprayed from the pesticide/fertilizer spray nozzle 32 may be changeable. The type of pesticide/fertilizer F may be changed for each type of crop C.

Next, the high temperature damage suppression method according to this embodiment will be described with reference to FIG. 7. FIG. 7 is a flow chart showing an example of the steps of the high temperature damage suppression method according to this embodiment. First, the brightness detection unit 8 determines whether it is nighttime or not in the farmland N (step S1, process of determining whether it is nighttime or not). For example, the judgment unit of the brightness detection unit 8 judges whether the amount of light received by the light receiving element of the brightness detection unit 8 is equal to or greater than a certain value, and it is determined from the result of this judgment whether it is nighttime or not in the farmland N. The result of this judgment is output to the controller 10.

If the brightness detection unit 8 determines that it is not nighttime in the farmland N (NO in step S1), the controller 10 determines whether the temperature D2 of the farmland N is equal to or higher than the temperature threshold (step S2: determining whether the temperature of the farmland is equal to or higher than the temperature threshold). Specifically, the high temperature damage determination unit 15 of the controller 10 determines whether the time during which the temperature D2 is equal to or higher than the temperature threshold continues for equal to or higher than the time threshold.

If the controller 10 determines that the temperature D2 of the farmland N is not equal to or greater than the temperature threshold (NO in step S2), the series of steps is completed. If the controller 10 determines that the temperature D2 of the farmland N is equal to or greater than the temperature threshold (YES in step S2), the control unit 11 drives the panel adjuster 4 to operate the solar panel P so as to increase the shadow S (step S3: operating the solar panel to increase the shadow). At this time, the control unit 11 rotates each solar panel P, for example, to increase the tilt angle θ, and then the series of steps is completed.

On the other hand, if the brightness detection unit 8 determines that the farmland N is at night (YES in step S1), the controller 10 determines whether the temperature D2 of the farmland N is equal to or higher than the temperature threshold, as in step S2 (step S4: determining whether the temperature of the farmland is equal to or higher than the temperature threshold). Note that the temperature threshold used in step S2 (when it is not nighttime on the farmland) and the temperature threshold used in step S4 (when it is nighttime on the farmland) may be different from each other.

If the controller 10 determines that the temperature of the farmland N is not equal to or higher than the temperature threshold (NO in step S4), the series of steps is completed. If the controller 10 determines that the temperature D2 of the farmland N is equal to or higher than the temperature threshold (YES in step S4), the control unit 11 drives the panel adjuster 4 to tilt the solar panel P so that more wind enters the farmland N (step of tilting the solar panel so that more wind enters the farmland, step S5). At this time, each solar panel P is tilted so that the light receiving surface P1 is parallel to the wind direction D4 measured by the wind measuring device 7. After the above steps, the series of steps is completed.

Next, the effects of the photovoltaic power generation system 1 and the high temperature damage suppression method according to this embodiment will be described. The photovoltaic power generation system 1 includes a high temperature damage determination unit 15 that determines whether high temperature damage will occur to the crops C cultivated on the farmland N based on the temperature D2 of the farmland N, and a brightness detection unit 8 that detects whether the farmland N is at night. The photovoltaic power generation system 1 includes a control unit 11 that controls the adjustment of the size of the shadow S by the panel adjuster 4. When it is determined that high temperature damage will occur and the brightness detection unit 8 determines that the farmland N is not at night, the control unit 11 operates the solar panel P to increase the area of the shadow S formed on the farmland N. Therefore, when it is determined that high temperature damage will occur and the farmland N is not at night, the area of the shadow S of the farmland N increases, so that high temperature damage to the crops C on the farmland N can be suppressed.

When the control unit 11 determines that high temperature damage will occur and the brightness detection unit 8 determines that the farmland N is at night, it tilts the solar panel P to promote radiative cooling in the farmland N. By promoting radiative cooling in the farmland N, it is possible to prevent hot air from accumulating in the farmland N at night, thereby suppressing the occurrence of high temperature damage at night. In other words, it is possible to increase the heat dissipation properties of the farmland N at night and suppress high temperature damage. Therefore, since the occurrence of high temperature damage can be suppressed not only during the day but also at night, it is possible to increase the harvest yield of the crops C while collecting electricity with the solar panel P.

In this embodiment, the solar power generation system 1 is equipped with a water spray nozzle 31 that sprays water E onto the farmland N. When the high temperature damage determination unit 15 determines that high temperature damage will occur, the control unit 11 controls the water spray nozzle 31 to spray water E onto the farmland N from the water spray nozzle 31. Therefore, since water E is sprayed onto the farmland N from the water spray nozzle 31 when it is determined that high temperature damage will occur, high temperature damage to the crops C can be suppressed even at high temperatures. Furthermore, since the atmospheric temperature of the farmland N can be lowered by spraying the water E, the temperature of the solar panel P can be lowered and the amount of power generated by the solar panel P can be increased.

In this embodiment, the solar power generation system 1 is equipped with a pesticide fertilizer spraying nozzle 32 that sprays pesticide fertilizer F on the farmland N. When the high temperature damage determination unit 15 determines that a high temperature damage will occur, the control unit 11 controls the pesticide fertilizer spraying nozzle 32 to spray the pesticide fertilizer F from the pesticide fertilizer spraying nozzle 32 on the farmland N. Thus, since the pesticide fertilizer F is sprayed from the pesticide fertilizer spraying nozzle 32 when it is determined that a high temperature damage will occur, it is possible to prevent the crops C from withering due to high temperature damage.

In this embodiment, the solar power generation system 1 includes a plurality of nozzle units 30, each of which is fixed to the support structure 2 (beam member 2c). This eliminates the need for boom sprayers and large tractors for spraying water or pesticides. Furthermore, in this embodiment, the water spray nozzle 31 automatically sprays water, and the pesticide/fertilizer spray nozzle 32 automatically sprays pesticide/fertilizer, thereby contributing to labor savings.

In this embodiment, the solar power generation system 1 is equipped with a wind meter 7 that measures the wind volume D3 and wind direction D4 of the farmland N. When the wind volume D3 measured by the wind meter 7 is equal to or greater than the wind volume threshold, the control unit 11 controls the panel adjuster 4 to tilt the solar panel P so that the sunlight L receiving surface P1 of the solar panel P is parallel to the wind direction D4 measured by the wind meter 7. Thus, when the wind volume D3 is equal to or greater than the wind volume threshold, the solar panel P is tilted so that the light receiving surface P1 of the solar panel P is parallel to the wind direction D4 at that time. Therefore, when the wind is strong, the solar panel P is tilted so that the light receiving surface P1 of the solar panel P is parallel to the wind direction D4 of the wind, so that the wind stress on the solar panel P can be suppressed from increasing.

In this embodiment, the solar power generation system 1 is equipped with a blower 9 that blows wind W into the farmland N. When the high temperature damage determination unit 15 determines that high temperature damage will occur, the control unit 11 controls the blower 9 to blow wind W into the farmland N. Thus, since wind W is blown from the blower 9 into the farmland N when it is determined that high temperature damage will occur, high temperature damage to the crops C on the farmland N can be prevented.

The above describes an embodiment of the solar power generation system according to the present disclosure. However, the solar power generation system according to the present disclosure is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the gist of the claims. In other words, the configuration, function, shape, size, material, number, and arrangement of each part of the solar power generation system according to the present disclosure are not limited to the above-described embodiment, and can be modified as appropriate.

For example, in the above-mentioned embodiment, a brightness detection unit 8 including a light receiving element and a determination unit was described, in which the determination unit determines whether it is nighttime or not based on the amount of light received by the light receiving element. However, the brightness detection unit may not include a light receiving element and a determination unit. For example, the brightness detection unit may compare the times of sunrise and sunset obtained from the date D5 and time D6 with the current time to determine whether it is nighttime or not on farmland N.

For example, in the above embodiment, an example was described in which the water spray nozzle 31 automatically sprays water E on the farmland N, and the pesticide fertilizer spray nozzle 32 automatically sprays pesticide fertilizer F on the farmland N. However, the water spray nozzle 31 may manually spray water E on the farmland N (for example, by an operator pressing a button), and the pesticide fertilizer spray nozzle 32 may manually spray pesticide fertilizer F on the farmland N. In addition, the timing at which the water spray nozzle 31 sprays water E and the timing at which the pesticide fertilizer spray nozzle 32 sprays pesticide fertilizer F may be predetermined, and the control unit 11 may control each of the water spray nozzle 31 and the pesticide fertilizer spray nozzle 32 at the predetermined timing to spray water E and pesticide fertilizer F on the farmland N.

For example, in the above embodiment, the high temperature damage determination unit 15 determines whether or not there is a high temperature damage based on the air temperature D2, and when the high temperature damage determination unit 15 determines that there is a high temperature damage, the control unit 11 performs control to increase the size of the shadow S. However, the control unit 11 may further adjust the area of the shadow S by taking into account the growth stage of the crop C in the determination result by the high temperature damage determination unit 15. For example, when the crop C, whose growth period is 1/3 or less of a year, is cultivated in the farmland N, the control unit 11 may perform control to reduce the area of the shadow S only during that growth period. In addition, when the light saturation point is equal to or greater than the light saturation point D10 and sunlight L is not required, the control unit 11 may control the inclination of the solar panel P so that the inclination angle θ is 90°.

In the above embodiment, an example was described in which the solar panel P is tilted so that more wind can enter the farmland N when it is determined that a high temperature damage will occur and the brightness detection unit 8 determines that the farmland N is at night. However, when the high temperature damage determination unit 15 determines that a high temperature damage will not occur and the air temperature D2 is below a certain temperature, the control unit 11 may control to increase the tilt angle θ. In this case, the farmland C is kept warm during a period when it is necessary to keep the farmland C warm, preventing frost, and the growth promotion effect of the farmland C is enhanced, making it possible to manage the temperature of the farmland C. Furthermore, in the present disclosure, events other than high temperature damage may be determined. For example, the controller 10 may determine whether low temperature and high humidity will occur, and in this case, if the farmland C is rice, the occurrence of rice heat disease in the rice can be suppressed by controlling the tilt of the solar panel P so that the farmland N is hot and dry. Furthermore, when the controller 10 determines that the farmland C is rice and low temperature and high humidity will occur, a pesticide for rice heat disease countermeasures may be sprayed from the pesticide and fertilizer spraying nozzle 32.

For example, in the above embodiment, an example was described in which the crop C was rice and the farmland N was a rice field. However, the crop C may be something other than rice, and the farmland N may be farmland other than a rice field (e.g., a field).

1...Photovoltaic power generation system, 2...Support structure, 2b...Support column, 2c...Beam member, 3, 3A, 3B, 3C...Axis, 4...Panel regulator, 5...Pyranometer, 6...Thermometer, 7...Wind meter, 8...Brightness detector, 9...Blower, 10...Controller, 11...Control unit, 12...Database, 14...Communication unit, 15...High temperature damage determination unit, 16...Information terminal, 20...Network, 30...Nozzle unit, 31...Water spray nozzle, 32...Pesticide fertilizer spray nozzle, C...Crop, D1...Solar radiation, D2...Temperature, D3...Wind volume, D4...Wind direction, D5...Date, D6...Time, D 7...trajectory, D8...shadow information, D9...crops, D10...light saturation point, D11...weather information, D12...power generation, E...water, F...pesticides and fertilizers, H...high temperature damage determination table, L...sunlight, N...farmland, P, Q, R, X...solar panel, P1...light-receiving surface, Q1...cylinder, Q2...first plate-shaped member, Q3...second plate-shaped member, R1...first plate-shaped member, R2...main surface, R3...second plate-shaped member, R4...slide rail, S...shadow, T...sun, W...wind, X1...hinge mechanism, X2...first plate-shaped member, X3...second plate-shaped member, X5...light-receiving surface, Y...angle, Z...table, θ...tilt angle.

Claims (5)

A solar power generation system having solar panels installed above farmland,
a high temperature damage determination unit that determines whether or not high temperature damage will occur to crops grown in the farmland based on the temperature of the farmland;
A panel adjuster that operates the solar panel to adjust the size of the shadow formed on the farmland;
A brightness detection unit that detects whether it is nighttime or not;
a control unit that controls the adjustment of the size of the shadow by the panel adjuster;
Equipped with
The control unit is
When the high temperature damage determination unit determines that a high temperature damage will occur and the brightness detection unit determines that it is not nighttime, the panel regulator is controlled to operate the solar panel so as to increase the area of the shadow formed on the farmland,
When the high temperature damage determination unit determines that a high temperature damage will occur and the brightness detection unit determines that it is nighttime, the panel adjuster is controlled to tilt the solar panel so as to promote radiative cooling in the farmland.
Photovoltaic power generation system. A water spray nozzle for spraying water on the farmland is provided,
The control unit controls the water sprinkler nozzle to sprinkle water on the farmland from the water sprinkler nozzle when the high temperature damage determination unit determines that high temperature damage will occur.
The solar power generation system according to claim 1 . A pesticide fertilizer spraying nozzle for spraying pesticide fertilizer on the farmland is provided,
The control unit controls the pesticide and fertilizer spraying nozzle to spray the pesticide and fertilizer onto the farmland from the pesticide and fertilizer spraying nozzle when the high temperature damage determination unit determines that a high temperature damage will occur.
The solar power generation system according to claim 1 or 2. A wind gauge is provided to measure the wind volume and wind direction of the farmland,
When the wind volume measured by the wind meter is equal to or greater than a wind volume threshold, the control unit controls the panel adjuster to tilt the solar panel so that the sunlight receiving surface of the solar panel is parallel to the wind direction measured by the wind meter.
The solar power generation system according to any one of claims 1 to 3. A blower is provided to blow air into the farmland,
The control unit controls the blower to send air into the farmland when the high temperature damage determination unit determines that high temperature damage will occur.
The solar power generation system according to any one of claims 1 to 4.

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