Solar radiation amount calculation method and solar radiation amount calculating device

Abstract

In order to make it possible to calculate an amount of direct solar radiation and an amount of scattered solar radiation by means of a device having a simple configuration, this solar radiation amount calculation method involves calculating the amount of direct solar radiation and the amount of scattered solar radiation using at least one hemispherical glass dome (30) and two solar radiation meters (51), wherein, if the measured value from a first solar radiation meter is I1 and the measured value from a second solar radiation meter is I2, the amount of direct solar radiation D and the amount of scattered solar radiation S at a measurement time are calculated by solving simultaneous equations that express the measured value I1 and the measured value I2 using a direct solar radiation transmittance a and a scattered solar radiation transmittance b of sunlight directed toward the first solar radiation meter and a direct solar radiation transmittance c and a scattered solar radiation transmittance d of sunlight directed toward the second solar radiation meter.

Description

Solar radiation calculation method and solar radiation calculation device

[0001] The present invention relates to a method and an apparatus for calculating the amount of solar radiation, and more particularly to a method and an apparatus for calculating the amount of solar radiation that can calculate the amount of direct solar radiation and the amount of diffuse solar radiation using an apparatus with a simple configuration.

[0002] Fossil fuels are widely used to heat horticultural facilities, and decarbonization is required. On the other hand, solar energy is a sustainable energy source and could be one of the alternative heat sources for heating facilities. In addition, decarbonization of horticultural facilities is an urgent issue, and as effective use of local energy is being explored, there is growing expectation for using solar energy to store and heat horticultural facilities.

[0003] In order to use solar radiation energy for heat storage and heating of horticultural facilities, it is important to accurately grasp the amount of direct and diffuse solar radiation.

[0004] When observing direct and diffuse solar radiation, it is common to measure global and direct solar radiation, or global and diffuse solar radiation, based on the relationship "global solar radiation = direct solar radiation + diffuse solar radiation," and then determine the residuals, or diffuse and direct solar radiation, of each.

[0005] On the other hand, the development of an observation network for direct and diffuse solar radiation is still insufficient. One of the reasons for this is thought to be the need for expensive and time-consuming equipment. Until now, observations have often been carried out using a pyranometer and a solar tracking device to measure direct solar radiation, and a pyranometer for measuring global solar radiation and a solar shading band to measure diffuse solar radiation (see, for example, Non-Patent Document 1).

[0006] Archives for meteorology, geophysics, and bioclimatology. Ser. B. Climatology, environmental meteorology, radiation research, On the Measurement of Sky Radiation By A. J. Drummond

[0007] The use of a direct solar radiation meter and a solar tracking device, as well as a solar radiation shading band and a solar radiation measuring pyranometer for measuring global solar radiation as in Non-Patent Document 1, for example, results in a large burden in terms of cost and maintenance.

[0008] For example, direct solar radiation measurement equipment (pylanometers and solar trackers) is expensive, and when measuring diffuse solar radiation, the position of the solar radiation shading band needs to be adjusted every few days. In addition, the solar tracker and solar radiation shading band have moving parts, which can be damaged by dust and other particles.

[0009] As described above, there are areas in which conventional technology needs improvement in order to promote the development of an observation network for direct solar radiation and diffuse solar radiation.

[0010] One aspect of the present invention has been made in consideration of the above-mentioned problems, and one example of its purpose is to make it possible to calculate direct solar radiation and diffuse solar radiation using a device with a simple configuration.

[0011] In order to solve the above-mentioned problems, a solar radiation calculation method according to one aspect of the present invention calculates amounts of direct solar radiation and diffuse solar radiation using at least one hemispherical glass dome and two pyranometers, wherein the measured value I1 of a first pyranometer is I1, the measured value I2 of a second pyranometer is I2, the direct solar radiation transmittance of sunlight heading toward the first pyranometer is a, the diffuse solar radiation transmittance b is b, the direct solar radiation transmittance c is c, and the diffuse solar radiation transmittance d is d. By solving the simultaneous equations consisting of equations (1) and (2), the amount of direct solar radiation D and the amount of diffuse solar radiation S at the measurement time are calculated, where a:b≠c:d.

[0012] aD+bS=I1 (1) cD+dS=I2 (2) A solar radiation calculation device according to one aspect of the present invention calculates an amount of direct solar radiation D and an amount of diffuse solar radiation S at a measurement time by using at least one hemispherical glass dome and two pyranometers, the solar radiation calculation device comprising: a measurement value I1 from a first pyranometer; a measurement value I2 from a second pyranometer; a direct solar radiation transmittance of sunlight heading toward the first pyranometer; b a diffuse solar radiation transmittance of sunlight heading toward the second pyranometer; c a direct solar radiation transmittance of sunlight heading toward the second pyranometer; and d a diffuse solar radiation transmittance of sunlight heading toward the second pyranometer. The solar radiation calculation device comprises: a calculation unit that calculates an amount of direct solar radiation D and an amount of diffuse solar radiation S at a measurement time by solving the simultaneous equations consisting of equations (1) and (2), wherein a:b ≠ c:d.

[0013] According to one aspect of the present invention, the amount of direct solar radiation and the amount of diffuse solar radiation can be calculated using a device with a simple configuration.

[0014] 1 is a block diagram showing an example of the configuration of a solar radiation calculation system according to one embodiment of the present invention; FIG. 2 is a vertical cross-sectional view of a glass dome; FIG. 3 is a diagram showing an example of a calculation method for diffuse solar radiation transmittance; FIG. 4 is a flowchart explaining an example of the flow of a solar radiation calculation process; FIG. 5 is a graph showing changes in the ratio of direct solar radiation transmittance a to diffuse solar radiation transmittance b, and the ratio of direct solar radiation transmittance c to diffuse solar radiation transmittance d depending on the measurement date and time; and FIG. 6 is a diagram showing an example of the configuration of a computer that executes program instructions.

[0015] (First embodiment) Hereinafter, one embodiment of the present invention will be described in detail.

[0016] (Functional Configuration of Solar Radiation Calculation System) Fig. 1 is a block diagram showing an example of the configuration of a solar radiation calculation system according to this embodiment. The solar radiation calculation system 10 shown in the figure is a system for calculating the amount of direct solar radiation and the amount of diffuse solar radiation.

[0017] The solar radiation calculation system 10 includes a hemispherical glass dome 30-1, a pyranometer 51-1 arranged inside the glass dome 30-1, a hemispherical glass dome 30-2, a pyranometer 51-2 arranged inside the glass dome 30-2, and a solar radiation calculation device 71.

[0018] The glass domes 30-1 and 30-2 are each hollow and made of hemispherical transparent glass. Unless there is a particular need to distinguish between them, the glass domes 30-1 and 30-2 will be collectively referred to as the glass dome 30.

[0019] The pyranometers 51-1 and 51-2 have a sensor unit (not shown) that includes a thermopile, a photodiode, etc. Unless there is a particular need to distinguish between them, the pyranometers 51-1 and 51-2 will be collectively referred to as the pyranometer 51. The pyranometer 51 converts solar radiation received by the sensor unit into an electrical signal, measures the amount of solar radiation, and outputs the measurement result.

[0020] The glass dome 30 is placed on the ground, a table, a desk, or the like outdoors, and the ground, table, desk, or the like covered by the glass dome 30 is a circular area. The bottom of the glass dome is set horizontally, and the glass dome is set on that horizontal plane. For example, a pyranometer 51 is set on the bottom of a hemisphere. The center of these bottoms is indicated by a black circle in the figure, and the pyranometer 51 is set at a position other than the center of the bottom.

[0021] Moreover, the pyranometers 51-1 and 51-2 are installed at different positions within the circular area (the bottom surfaces of the glass domes 30-1 and 30-2) covered by the glass domes 30-1 and 30-2. That is, within the circle of the bottom surface covered by the glass domes, the pyranometer 51-1 is installed at a first position within the circle, and the pyranometer 51-2 is installed at a second position within the circle.

[0022] To be precise, the first position represents the center of the sensing part (such as a solar radiation sensor) of the pyranometer 51-1, and the second position represents the center of the sensing part (such as a solar radiation sensor) of the pyranometer 51-2. However, for example, if the sizes of the pyranometers 51-1 and 51-2 are sufficiently small compared to the sizes of the glass domes 30-1 and 30-2, any part of the pyranometer 51-1 may be approximated as the first position, and any part of the pyranometer 51-2 may be approximated as the second position.

[0023] For example, if the volume of the housing that constitutes the pyranometer 51 is sufficiently small compared to the volume of the glass dome 30, the first position and the second position may be approximated as described above. More specifically, if the pyranometer is constituted by a cylindrical housing, and the area of ​​the base of this cylinder is sufficiently small compared to the area of ​​the base of the glass dome 30, and the height of this cylinder is sufficiently small compared to the height of the glass dome 30, the first position and the second position may be approximated as described above.

[0024] As an example, the center of the bottom of pyranometer 51-1 or pyranometer 51-2 may be approximated as the first position or the second position, respectively. For example, a position within a first circle that forms the bottom of the hemisphere corresponding to glass dome 30-1 and a position within a second circle that forms the bottom of the hemisphere corresponding to glass dome 30-2 are each represented by coordinates (x, y). Here, the east-west direction is the x-axis, the north-south direction is the y-axis, and the center of the circle is represented by coordinates (0, 0). The coordinate values ​​within the circle that forms the bottom of the hemisphere corresponding to glass dome 30 are calculated by dividing the distances in the x- and y-axes from the center point of the circle that forms the bottom of the hemisphere corresponding to glass dome 30 by the radius of the circle that forms the bottom of the hemisphere corresponding to glass dome 30.

[0025] Then, the pyranometer 51-1 and the pyranometer 51-2 are installed so that the coordinates corresponding to the first position in the first circle and the coordinates corresponding to the second position in the second circle are different coordinates.

[0026] The solar radiation calculation device 71 includes an input unit 91 , a calculation execution unit 92 , an output unit 93 , and a communication unit 94 .

[0027] The input unit 91 supplies information input through, for example, a user operation to the calculation execution unit 92. The calculation execution unit 92 executes calculations to calculate the amount of direct solar radiation and the amount of diffuse solar radiation based on the information input from the input unit 91 and / or information acquired through the communication unit 94.

[0028] The output unit 93 outputs the calculation results of the calculations executed by the calculation execution unit 92 to, for example, a display. The communication unit 94, for example, accesses a network (not shown) such as the Internet as necessary, and communicates with other devices connected to the network.

[0029] (Light path of sunlight) Figure 2 is a vertical cross-sectional view of glass dome 30-1 or glass dome 30-2. In the figure, the part indicated by arc A corresponds to the glass surface, and the part indicated by line B is the bottom of the hemisphere, which corresponds to the circular area covered by the glass dome. Point P1 shown on line B indicates the center of the circle that is the bottom of the hemisphere, and point P2 indicates a point other than the center of the circle.

[0030] The dotted lines in the figure indicate the optical paths of sunlight incident on point P1. Although five dotted lines are shown in the figure, in reality there are many more optical paths. The dotted lines in the figure are normals to arc A. In other words, the optical path of sunlight incident on point P1 is perpendicular to the tangent plane at the intersection of the optical path and the glass of glass dome 30-1 or glass dome 30-2, regardless of the direction of the optical path.

[0031] In the figure, the optical path of sunlight incident on point P2 is shown by a solid line. Here, five solid lines indicate optical paths that pass through the intersections of the optical path shown by the dotted line with the glass dome. As shown in the figure, the angle between the solid line and the dotted line is different at each intersection. The angle between the solid line and the dotted line determines the angle of incidence of sunlight incident on point P2 at each intersection. If the angle of incidence of sunlight is different, the refraction angle will also be different, and therefore the transmittance formed by both angles will also be different.

[0032] Direct solar radiation is the amount of solar radiation that reaches the area directly from the sun, so if the installation position of pyranometer 51 and the direction and altitude of the sun are specified, the intersection point of the optical path of the sunlight and the glass of glass dome 30-1 or glass dome 30-2 can be specified. Since the direction and altitude of the sun change depending on the date and time, one optical path is determined for the amount of direct solar radiation depending on the date and time. On the other hand, diffuse solar radiation is the amount of solar radiation that reaches the area after being reflected by clouds, the atmosphere, etc., so there are always many optical paths.

[0033] As described above, the optical path of sunlight incident on point P1 is perpendicular to the tangent plane at the intersection of the optical path and the glass, regardless of the direction of the optical path. Therefore, for sunlight incident on point P1, the transmittance of sunlight related to the amount of direct solar radiation and the amount of diffuse solar radiation that pass through glass dome 30 are always constant, regardless of the solar azimuth and altitude.

[0034] Here, the transmittance of sunlight related to the amount of direct solar radiation is referred to as the direct solar radiation transmittance, and the transmittance of sunlight related to the amount of diffuse solar radiation is referred to as the diffuse solar radiation transmittance.

[0035] On the other hand, as described above, the optical path of sunlight incident at point P2 has different angles relative to the tangent plane depending on the position of the intersection with the glass, and the angle of incidence varies depending on the position of the intersection. In other words, the transmittance varies depending on the optical path. Therefore, for sunlight incident at point P2, the direct solar transmittance after passing through glass dome 30 varies depending on the solar azimuth and altitude, but if we assume that the diffuse solar radiation reaching glass dome 30 is uniform in all directions in the sky, the diffuse solar transmittance will always be constant regardless of the solar azimuth and altitude.

[0036] (Measurement of Solar Radiation Amounts Inside Two Glass Domes) In this embodiment, the solar radiation amount I measured by two pyranometers (for example, pyranometer 51-1 and pyranometer 51-2) is １ and I ２ is expressed by the following equations (1) and (2).

[0037] ...(1)

[0038] In equations (1) and (2), D represents the amount of direct solar radiation at the time of measurement, and S represents the amount of diffuse solar radiation at the time of measurement. The direct solar transmittance of sunlight passing through glass dome 30-1 toward the position of pyranometer 51-1 is represented by a, the diffuse solar transmittance is represented by b, the direct solar transmittance of sunlight passing through glass dome 30-2 toward the position of pyranometer 51-2 is represented by c, and the diffuse solar transmittance is represented by d.

[0039] In this embodiment, the calculation execution unit 92 calculates the amount of direct solar radiation D and the amount of diffuse solar radiation S at the measurement time by solving the simultaneous equations consisting of equations (1) and (2).

[0040] As described above, in this embodiment, in a solar radiation calculation method for calculating direct solar radiation and diffuse solar radiation using two hemispherical glass domes and two pyranometers, where the measurement value of the first pyranometer is I1, the measurement value of the second pyranometer is I2, the direct solar radiation transmittance of sunlight heading toward the first pyranometer is a, the diffuse solar radiation transmittance is b, and the direct solar radiation transmittance of sunlight heading toward the second pyranometer is c and the diffuse solar radiation transmittance is d, the measurement value I1 of the first pyranometer and the measurement value I2 of the second pyranometer are expressed by equations (1) and (2): aD+bS=I1 (1) cD+dS=I2 (2) By solving the simultaneous equations consisting of equations (1) and (2), the amount of direct solar radiation D and the amount of diffuse solar radiation S at the measurement time are calculated, where a:b≠c:d.

[0041] (Calculation of Direct Solar Transmittance) The direct solar transmittance a is calculated based on the angle of incidence on the glass dome 30-1, which is determined by geometric calculation based on the radius of the glass dome 30-1, the position of the pyranometer 51-1, and the solar azimuth and altitude. The direct solar transmittance c is calculated based on the angle of incidence on the glass dome 30-2, which is determined by geometric calculation based on the radius of the glass dome 30-2, the position of the pyranometer 51-2, and the solar azimuth and altitude. In other words, the solar transmittance value obtained based on the position of the sun is calculated as the direct solar transmittance a or the direct solar transmittance c. It is assumed that the types and thicknesses of the glass of the glass domes 30-1 and 30-2 are known.

[0042] In this way, the calculation execution unit 92 calculates the angle of incidence of the sunlight related to the amount of direct solar radiation that is incident on the positions of the pyranometers 51-1 and 51-2 at the time of measurement by identifying the optical path of the sunlight related to the amount of direct solar radiation and the point of intersection on the surface of the glass dome 30-1 or 30-2 based on the azimuth and altitude of the sun, the positions of the pyranometers 51-1 and 51-2, and the radii of the glass domes 30-1 and 30-2, and identifies the value of the direct solar radiation transmittance a or the direct solar radiation transmittance c based on the angle of incidence.

[0043] The method for calculating the solar transmittance value based on the angle of incidence is described in detail in, for example, "Architectural Environmental Engineering, edited by Urano Yoshimi and Nakamura Hiroshi, Morikita Publishing, 1st Edition, 1996."

[0044] (Calculation of Diffuse Solar Transmittance) The calculation execution unit 92 calculates the diffuse solar transmittance b and the diffuse solar transmittance d based on sunlight incident from radiation directions corresponding to calculation points located on the bottom surface of a hemispherical virtual dome installed around the first and second positions. The radiation direction will be described later. The bottom surface of the virtual dome is installed horizontally, and the virtual dome is installed on that horizontal plane.

[0045] 3 is a diagram illustrating an example of a method for calculating the diffuse solar transmittance b and the diffuse solar transmittance d. When the diffuse solar transmittance b and the diffuse solar transmittance d are calculated from calculation points arranged on the bottom surface of the virtual dome, the calculation points are set in a circular area corresponding to the bottom surface of the virtual dome, for example. The number of calculation points may be, for example, 1 million.

[0046] In the example of Fig. 3, the diffuse solar transmittance b is to be calculated. In Fig. 3, a virtual dome 40-1 is installed inside a glass dome 30-1. Note that the virtual dome 40-1 is not actually installed, but is a hemispherical dome installed virtually to identify the position required for calculating the diffuse solar transmittance b.

[0047] For example, the size of the pyranometer 51-1 and the size of the virtual dome 40-1 may be set to be approximately equal. The virtual dome 40-1 is installed so that the center point Q0 of the bottom surface of the virtual dome 40-1 is equal to the position of the sensor of the pyranometer 51-1.

[0048] An estimation point is placed on the bottom surface 111 of the virtual dome 40-1. Note that the estimation point is not actually placed, but may be data that is virtually placed in order to identify a position required for executing the processing described below.

[0049] When arranging the calculation points, one calculation point is arranged at the center point Q0 of the bottom surface 111 of the virtual dome 40-1. Then, six calculation points are arranged at equal intervals so as to surround the calculation point corresponding to the center point Q0 in a circular shape. Twelve calculation points are arranged at equal intervals so as to surround the outside of a first circle formed by these six calculation points in a circular shape. Then, 18 calculation points are arranged at equal intervals so as to surround the outside of a second circle formed by these 12 calculation points in a circular shape. In this way, the calculation points are arranged at equal intervals by increasing the number of calculation points by six, so as to form a third circle outside the second circle, a fourth circle outside the third circle, and so on. As an example, a total of approximately one million calculation points may be arranged.

[0050] Alternatively, the calculation points may be arranged as follows. For example, a set number N1 of calculation points is determined in advance. A calculation point corresponding to a center point Q0 is arranged, and calculation points are added in increments of six around the center point Q0, starting from the inside, to arrange the first circle, the second circle, the third circle, the fourth circle, and so on. Assume that the total number of calculation points corresponding to the center point Q0 and the first through M-th (circles) exceeds the set number N1. In this case, (N1-N2) calculation points, which are the difference between the total number N2 of the calculation points corresponding to the center point Q0 and the first through M-1-th (circles) and the set number N1, are arranged at equal intervals on the circumference of the M-th (outermost) circle. The calculation points may be arranged in this manner.

[0051] The calculation execution unit 92 identifies an arbitrary calculation point Q1. The calculation execution unit 92 calculates the coordinates of an intersection 41-1 between a line extending vertically upward from the calculation point Q1 and the virtual dome 40-1. The calculation execution unit 92 also defines the direction of the intersection 41-1 as a radial direction when viewed from the center point Q0, and calculates the coordinates of an intersection 31-1 between the radial direction and the glass dome 30-1.

[0052] The calculation execution unit 92 also determines the angle between the normal direction and the radial direction at the intersection 31-1 as the angle of incidence of sunlight.The calculation execution unit 92 then calculates the solar transmittance value based on the determined angle of incidence, thereby calculating the solar transmittance when passing through the glass of the glass dome 30-1.Through the processing up to this point, the solar transmittance in the radial direction corresponding to one calculation point Q1 on the bottom surface 111 of the virtual dome 40-1 is calculated.

[0053] The calculation execution unit 92 calculates the solar transmittance as described above for all remaining calculation points within the bottom surface 111 of the virtual dome 40-1. For example, if one million calculation points are set within the bottom surface 111, one million different solar transmittances are calculated. Then, the calculation execution unit 92 calculates the average value of the one million calculated solar transmittances as the transmittance of sunlight related to the amount of scattered solar radiation when it passes through glass, i.e., the scattered solar transmittance b.

[0054] Similarly, by calculating the solar transmittance value based on the angle of incidence, the solar transmittance when passing through the glass of the glass dome 30-2 can also be calculated. That is, the diffuse solar transmittance d of the glass dome 30-2 is calculated.

[0055] In this way, the calculation execution unit 92 calculates the direct solar radiation transmittance a, the direct solar radiation transmittance c, the diffuse solar radiation transmittance b, and the diffuse solar radiation transmittance d, and solves the simultaneous equations of the above-mentioned formulas (1) and (2), thereby calculating the amount of direct solar radiation D and the amount of diffuse solar radiation S. Note that in order to solve the simultaneous equations of formulas (1) and (2), a:b ≠ c:d is a condition. For this reason, the pyranometers 51-1 and 51-2 are installed at positions that satisfy the condition that the ratios of the direct solar radiation transmittance and the diffuse solar radiation transmittance at the installation positions of the two pyranometers do not match.

[0056] (Solar Radiation Calculation Processing) Next, an example of the solar radiation calculation processing of this embodiment will be described. Fig. 4 is a flowchart illustrating an example of the flow of the solar radiation calculation processing.

[0057] In step S21, two hemispherical glass domes are installed. At this time, for example, glass domes 30-1 and 30-2 are installed as described above. Note that glass domes 30-1 and 30-2 are placed outdoors on the ground, a table, a desk, or the like, and the ground surface, table top, desk top, or the like covered by glass domes 30-1 and 30-2 are circular areas.

[0058] In step S22, two pyranometers are installed. At this time, for example, as described above, pyranometers 51-1 and 51-2 are installed in the circular areas covered by glass domes 30-1 and 30-2. Note that pyranometers 51-1 and 51-2 are installed at positions other than the centers of the bottom surfaces of the glass domes.

[0059] As described above, the pyranometers 51-1 and 51-2 are installed at different positions within the circular areas covered by the glass domes 30-1 and 30-2.

[0060] Furthermore, as described above, the pyranometers 51-1 and 51-2 are installed at positions that satisfy the condition that the ratios of the direct solar radiation transmittance and the diffuse solar radiation transmittance at the installation positions of the two pyranometers do not match (a:b ≠ c:d).

[0061] In step S23, the calculation execution unit 92 of the solar radiation calculation device 71 calculates the direct solar radiation transmittance.

[0062] In this case, for example, as described above, the direct solar transmittance a is calculated by geometric calculation based on the radius of the glass dome 30-1, the position of the pyranometer 51-1, and the solar azimuth and altitude. The direct solar transmittance c is calculated by geometric calculation based on the radius of the glass dome 30-2, the position of the pyranometer 51-2, and the solar azimuth and altitude. It is assumed that the types and thicknesses of the glass of the glass domes 30-1 and 30-2 are known.

[0063] In step S24, the calculation execution unit 92 of the solar radiation calculation device 71 calculates the diffuse solar radiation transmittance. At this time, for example, as described above, the calculation execution unit 92 calculates the diffuse solar radiation transmittance b and the diffuse solar radiation transmittance d based on the calculation point on the bottom surface 111 of the virtual dome.

[0064] In step S25, the calculation execution unit 92 of the solar radiation calculation device 71 acquires the measured values ​​of the pyranometers. As a result, for example, the solar radiation I measured by the pyranometers 51-1 and 51-2 is calculated. １ and solar radiation I ２ is obtained.

[0065] In step S26, the calculation execution unit 92 of the solar radiation calculation device 71 generates simultaneous equations. At this time, for example, simultaneous equations consisting of the above-mentioned formula (1) and formula (2) are generated. Note that the values ​​calculated in step S23 are used for the direct solar radiation transmittance a and the direct solar radiation transmittance c in formula (1) and formula (2). The values ​​calculated in step S24 are used for the diffuse solar radiation transmittance b and the diffuse solar radiation transmittance d. Solar radiation I １ and solar radiation I ２ The value obtained in step S25 is used for .

[0066] In step S27, the calculation execution unit 92 of the solar radiation calculation device 71 calculates the amount of direct solar radiation D and the amount of scattered solar radiation S by solving the simultaneous equations generated in step S26.

[0067] In this way, the solar radiation calculation process is performed.

[0068] Effect of First Embodiment As described above, the solar radiation calculation system 10 according to this embodiment can calculate the amount of direct solar radiation and the amount of diffuse solar radiation without using any special equipment. For example, unlike the conventional method, it is not necessary to prepare a direct solar radiation meter and a solar tracking device to measure direct solar radiation, and a solar radiation shading band and a solar radiation measuring pyranometer to measure diffuse solar radiation, but two glass domes and two pyranometers are sufficient.

[0069] Therefore, for example, an expensive direct solar radiation meter and a solar tracking device are not required, and work such as adjusting the position of a solar radiation shading band is also not required. Furthermore, since there is no need to use devices with moving parts such as a solar tracking device and a solar radiation shading band, there is a low possibility of malfunction even when installed outdoors, and the burden in terms of cost and maintenance is small. Furthermore, the solar radiation calculation device 71 according to this embodiment can calculate the amount of direct solar radiation and the amount of diffuse solar radiation from the measurements of the two pyranometers.

[0070] As described above, according to this embodiment, the amount of direct solar radiation and the amount of diffuse solar radiation can be calculated using a device with a simple configuration.

[0071] (Embodiment 2) In the first embodiment, an example has been described in which the pyranometers 51-1 and 51-2 are installed on the bottom surfaces of the glass domes 30-1 and 30-2, respectively. However, the pyranometer 51-1 may be installed above the bottom surface of the glass dome 30-1, and the pyranometer 51-2 may be installed above the bottom surface of the glass dome 30-2. In this case, the pyranometer 51-1 may be placed at any position within the glass dome 30 other than the center of the bottom surface of the glass dome 30.

[0072] That is, the pyranometer 51-1 may be installed at a first position within a hemispherical space covered by a first hemispherical glass dome, and the pyranometer 51-2 may be installed at a second position within a hemispherical space covered by a second hemispherical glass dome, where the first and second positions are positions other than the center of the bottom surface of each glass dome.

[0073] In this case, for example, the position of the hemisphere corresponding to glass dome 30-1 in the first space and the position of the hemisphere corresponding to glass dome 30-2 in the second space are each expressed in (x, y, z) coordinates. Here, the east-west direction is the x-axis, the north-south direction is the y-axis, the direction perpendicular to the ground, table top, desk top, or other surface covered by glass dome 30 is the z-axis, and the vertically upward direction is the z-axis. The center of the circle that forms the bottom of the hemisphere corresponding to glass dome 30 is expressed as coordinates (0, 0, 0). The spatial coordinate values ​​within glass dome 30 are calculated by dividing the distances in the x-, y-, and z-axes from the center point of the circle that forms the bottom of the hemisphere corresponding to glass dome 30 by the radius of the circle that forms the bottom of the hemisphere corresponding to glass dome 30.

[0074] Then, the pyranometer 51-1 and the pyranometer 51-2 are installed so that the coordinates corresponding to the first position in the first space and the coordinates corresponding to the second position in the second space are different coordinates.

[0075] In the first and second embodiments, examples have been described in which the pyranometers 51-1 and 51-2 are installed at positions other than the center of the bottom surface of the glass dome. However, one of the pyranometers 51-1 and 51-2 may be installed at the center of the bottom surface of the glass dome, and the other may be installed at a position other than the center of the bottom surface of the glass dome.

[0076] The center of the bottom surface of the glass dome is the center of the circle that forms the bottom surface of the hemisphere that corresponds to glass dome 30. For example, if the east-west direction is the x-axis, the north-south direction is the y-axis, and the vertical direction that is perpendicular to the surface covered by glass dome 30, such as the ground surface, table top, or desk top, is the z-axis, the center of the bottom surface of glass dome 30 is the position indicated by the coordinates (0,0,0).

[0077] For example, if the pyranometer 51-1 is installed at the center of the bottom surface of the glass dome 30-1, the direct solar transmittance a of sunlight passing through the glass dome 30-1 toward the position of the pyranometer 51-1 will be the same as the diffuse solar transmittance b of sunlight passing through the glass dome 30-1 toward the position of the pyranometer 51-1. In other words, regardless of the position of the sun, the direct solar transmittance a will be equal to the diffuse solar transmittance b.

[0078] In other words, when the pyranometer 51-1 is installed at the center of the bottom surface of the glass dome 30-1, a = b, regardless of the measurement date and time. Note that the actual values ​​of the direct solar transmittance a and the diffuse solar transmittance b are determined according to the type and thickness of the glass.

[0079] When the pyranometer 51-1 is installed at the center of the bottom surface of the glass dome 30-1 and the pyranometer 51-2 is installed at a position other than the center of the bottom surface of the glass dome 30-2, the above-mentioned equations (1) and (2) can be modified into equations (3) and (4), respectively.

[0080] ...(3)

[0081] ...(4) Here, the simultaneous equations consisting of equations (3) and (4) can be solved if c / d, which is the coefficient of the amount of direct solar radiation D in equation (4), is not 1. In other words, the pyranometer 51-2 needs to be installed in a position where the values ​​of c and d are always different, regardless of the measurement time.

[0082] 5 is a graph showing the change in the ratio of direct solar radiation transmittance a to diffuse solar radiation transmittance b, and the ratio of direct solar radiation transmittance c to diffuse solar radiation transmittance d depending on the measurement date and time. Here, it is assumed that pyranometer 51-1 is installed at the center of the bottom surface of glass dome 30-1, and pyranometer 51-2 is installed at a position other than the center of the bottom surface of glass dome 30-2.

[0083] In Figure 5, the horizontal axis represents the date, and the vertical axis represents the ratio of direct solar transmittance a (or c) to diffuse solar transmittance b (or d), with changes in the value of a / b shown by line 211 and changes in the value of c / d shown by line 222.

[0084] As described above, since pyranometer 51-1 is installed at the center of the bottom surface of glass dome 30-1, the value of a / b indicated by line 211 is always 1 regardless of the date and time of measurement. In contrast, since pyranometer 51-2 is installed at a position other than the center of the bottom surface of glass dome 30-2, the value of c / d indicated by line 222 changes depending on the date and time of measurement.

[0085] Here, at the position where the pyranometer 51-2 is installed, the values ​​of c and d are always different regardless of the measurement time, and therefore the value indicated by the line 222 never becomes 1. In other words, the pyranometer 51-2 needs to be installed at such a position.

[0086] As described above, the amount of direct solar radiation D and the amount of diffuse solar radiation S are derived by solving the simultaneous equations consisting of equations (3) and (4) obtained by transforming equations (1) and (2).

[0087] In this way, one of the two pyranometers may be installed at the center of the bottom surface of the glass dome.

[0088] For example, if the position of pyranometer 51-1 is defined as the first position and the position of pyranometer 51-2 is defined as the second position, the first position may be the center of the bottom surface of the first glass dome and the second position may be a position other than the center of the bottom surface of the second glass dome, or the first position may be a position other than the center of the bottom surface of the first glass dome and the second position may be the center of the bottom surface of the second glass dome.

[0089] (Embodiment 4) In the first to third embodiments, an example has been described in which two pyranometers are installed inside a glass dome (inside the glass dome). However, one of the pyranometers 51-1 and 51-2 may be installed inside the glass dome and the other outside the glass dome. In this case, one of the pyranometers needs to be installed at a position other than the center of the bottom surface of the glass dome. Note that the center of the bottom surface of the glass dome is the position indicated by the coordinates (0,0,0), for example, where the east-west direction is the x-axis, the north-south direction is the y-axis, and the direction perpendicular to the surface of the ground, table, desk, or the like covered by the glass dome and the vertically upward direction is the z-axis.

[0090] In this case, only one glass dome is required. For example, if the pyranometer 51-1 is installed outside the glass dome, the direct solar transmittance a and the diffuse solar transmittance b of sunlight heading toward the position of the pyranometer 51-1 will naturally be 1 because the sunlight does not pass through any obstruction. In other words, regardless of the position of the sun (i.e., the measurement date and measurement time), the direct solar transmittance a is equal to the diffuse solar transmittance b, and the value is 1.

[0091] In this case, too, as explained in the third embodiment, the simultaneous equations consisting of equations (3) and (4) can be solved unless c / d, which is the coefficient of the amount of direct solar radiation D in equation (4), is 1. In other words, as described above, the amount of direct solar radiation D and the amount of diffuse solar radiation S can be derived by solving the simultaneous equations consisting of equations (3) and (4) obtained by transforming equations (1) and (2).

[0092] In this embodiment, as in the third embodiment, the pyranometer 51-2 inside the glass dome must be installed at a position where the values ​​of c and d are always different, regardless of the measurement time.

[0093] In this way, one of the two pyranometers may be installed outside the glass dome. That is, the solar radiation calculation method according to the first to fourth embodiments calculates the amount of direct solar radiation and the amount of diffuse solar radiation using at least one hemispherical first glass dome and two pyranometers.

[0094] (Example of Implementation by Software) The functions of the solar radiation calculation device 71 can be realized by a program for causing a computer to function as the device, and by a program for causing a computer to function as each block of the device.

[0095] Fig. 6 is a block diagram illustrating the physical configuration of a computer 500 used as the solar radiation calculation device 71. As shown in Fig. 6, the computer 500 can be configured by a computer including a bus 510, a processor 501, a main memory 502, an auxiliary memory 503, a communication interface 504, and an input / output interface 505. The processor 501, the main memory 502, the auxiliary memory 503, the communication interface 504, and the input / output interface 505 are connected to one another via the bus 510. An input device 506 and an output device 507 are connected to the input / output interface 505.

[0096] The processor 501 may be, for example, a CPU (Central Processing Unit), a microprocessor, a digital signal processor, a microcontroller, or a combination of these.

[0097] The main memory 502 may be, for example, a semiconductor RAM (random access memory).

[0098] The auxiliary memory 503 may be, for example, a flash memory, a hard disk drive (HDD), a solid state drive (SSD), or a combination of these. The auxiliary memory 503 stores a program for causing the processor 501 to execute the solar radiation calculation process described above. The processor 501 loads the program stored in the auxiliary memory 503 onto the main memory 502 and executes each command included in the loaded program.

[0099] The program may be recorded not temporarily but on one or more recording media that can be read by the computer 500. The recording media may or may not be included in the computer 500. In the latter case, the program may be supplied to the computer 500 via any wired or wireless transmission medium.

[0100] The communication interface 504 is an interface for connecting to an external network.

[0101] The input / output interface 505 may be, for example, a USB interface, a short-range communication interface such as infrared or Bluetooth (registered trademark), or a combination of these.

[0102] The input device 506 may be, for example, a keyboard, a mouse, a touchpad, a microphone, or a combination thereof. The output device 507 may be, for example, a display, a printer, a speaker, or a combination thereof.

[0103] [Summary] A solar radiation calculation method according to a first aspect of the present invention is a solar radiation calculation method that calculates direct solar radiation and diffuse solar radiation using at least one hemispherical glass dome and two pyranometers, wherein the measurement value of a first pyranometer is I1, the measurement value of a second pyranometer is I2, the direct solar radiation transmittance of sunlight heading toward the first pyranometer is a, the diffuse solar radiation transmittance is b, and the direct solar radiation transmittance of sunlight heading toward the second pyranometer is c and the diffuse solar radiation transmittance is d, the measurement value I1 of the first pyranometer and the measurement value I2 of the second pyranometer are expressed by equations (1) and (2): aD+bS=I1 (1) cD+dS=I2 (2) By solving the simultaneous equations consisting of equations (1) and (2), the amount of direct solar radiation D and the amount of diffuse solar radiation S at the measurement time are calculated, where a:b≠c:d.

[0104] A solar radiation calculation method according to Aspect 2 of the present invention is the solar radiation calculation method according to Aspect 1 above, wherein the two pyranometers are installed in two hemispherical glass domes, and in a space covered by a first glass dome, a measurement value of a first pyranometer installed at a first position within the hemispherical space is denoted by I1, and in a space covered by a second glass dome, a measurement value of a second pyranometer installed at a second position different from the first position within the hemispherical space is denoted by I2, where a direct solar transmittance of sunlight passing through the first glass dome toward the first position is denoted by a and a diffuse solar transmittance is denoted by b, and a direct solar transmittance of sunlight passing through the second glass dome toward the second position is denoted by c and a diffuse solar transmittance is denoted by d, and the direct solar transmittance of sunlight passing through the second glass dome toward the second position is denoted by c and a diffuse solar transmittance is denoted by d, and the direct solar radiation D and the diffuse solar radiation S at the measurement time are calculated by solving the simultaneous equations consisting of Equation (1) and Equation (2) above.

[0105] A solar radiation calculation method according to aspect 3 of the present invention is the same as that of aspect 2 above, in which the angle of incidence of sunlight associated with direct solar radiation incident on the first position or the second position at the time of measurement is calculated by identifying the optical path of sunlight associated with direct solar radiation and the intersection point on the surface of the first glass dome or the second glass dome based on the azimuth and altitude of the sun, the first position and the second position, and the radius of the first glass dome and the radius of the second glass dome, and the value of the direct solar radiation transmittance a or the direct solar radiation transmittance c is determined based on the angle of incidence.

[0106] The solar radiation calculation method according to aspect 4 of the present invention calculates the diffuse solar transmittance b and the diffuse solar transmittance d based on sunlight incident from a radiation direction corresponding to a calculation point located on the bottom surface of a hemispherical virtual dome centered on the first position and the second position in the above-mentioned aspect 2 or 3.

[0107] A solar radiation calculation method according to aspect 5 of the present invention, in accordance with aspect 4 above, calculates virtual intersection coordinates, which are the coordinates of the intersection between a straight line extending vertically upward from one calculation point within the bottom surface and the surface of the virtual dome, and, with the direction of the virtual intersection coordinates as seen from the first position and the second position as the radiation direction, calculates the included angle between the radiation direction and the normal direction at the intersection between the radiation direction and the surface of the first glass dome and the intersection between the radiation direction and the surface of the second glass dome, and sets the included angle as the angle of incidence. Calculates the solar transmittance corresponding to one calculation point within the bottom surface, and calculates the diffuse solar transmittance b and the diffuse solar transmittance d by averaging the solar transmittances at all calculation points within the bottom surface.

[0108] A solar radiation calculation method according to aspect 6 of the present invention is, in any of aspects 2 to 5 above, such that the first position and the second position are different from the first position, and the first position is a position other than the center of the bottom surface of the first glass dome, and the second position is a position other than the center of the bottom surface of the second glass dome.

[0109] A solar radiation calculation method according to aspect 7 of the present invention is, in any of aspects 2 to 5 above, such that the first position and the second position are such that the first position is the center of the bottom surface of the first glass dome and the second position is a position other than the center of the bottom surface of the second glass dome, or the first position is a position other than the center of the bottom surface of the first glass dome and the second position is the center of the bottom surface of the second glass dome.

[0110] A solar radiation calculation method according to an eighth aspect of the present invention is the solar radiation calculation method according to the above-mentioned second aspect, wherein, of the two pyranometers, a first pyranometer is installed outside a hemispherical glass dome and a second pyranometer is installed inside the hemispherical glass dome, and wherein, when a measurement value of the first pyranometer installed at a first position outside the glass dome is I1 and a measurement value of the second pyranometer installed at a second position in the space covered by the glass dome is I2, the values ​​of the direct solar transmittance a and the diffuse solar transmittance b of sunlight heading toward the first pyranometer are set to 1, the direct solar transmittance c and the diffuse solar transmittance d of sunlight passing through the glass dome toward the second position are set to

[0111] A solar radiation calculation device according to a ninth aspect of the present invention is a solar radiation calculation device that calculates an amount of direct solar radiation and an amount of diffuse solar radiation using at least one hemispherical glass dome and two pyranometers, wherein the measured value of a first pyranometer is I1, the measured value of a second pyranometer is I2, a is the direct solar radiation transmittance of sunlight heading toward the first pyranometer, b is the diffuse solar radiation transmittance, and c is the direct solar radiation transmittance of sunlight heading toward the second pyranometer, and d is the diffuse solar radiation transmittance. The solar radiation calculation device further comprises a calculation execution unit that calculates the amount of direct solar radiation D and the amount of diffuse solar radiation S at the measurement time by solving the simultaneous equations consisting of equations (1) and (2), wherein a:b≠c:d.

[0112] 10 Solar radiation calculation system 30 Glass dome 51 Pyranometer 71 Solar radiation calculation device 91 Input unit 92 Calculation execution unit 93 Output unit 94 Communication unit 111 Bottom surface

Claims

1. A method for calculating direct solar radiation and diffuse solar radiation using at least one hemispherical glass dome and two pyranometers, wherein the measurement value of a first pyranometer is I1, the measurement value of a second pyranometer is I2, the direct solar radiation transmittance of sunlight heading toward the first pyranometer is a, the diffuse solar radiation transmittance is b, and the direct solar radiation transmittance of sunlight heading toward the second pyranometer is c and the diffuse solar radiation transmittance is d, the measurement value I1 of the first pyranometer and the measurement value I2 of the second pyranometer are expressed by equations (1) and (2), respectively: aD+bS=I1... (1) cD+dS=I2... (2) The direct solar radiation D and the diffuse solar radiation S at the measurement time are calculated by solving the simultaneous equations consisting of equations (1) and (2), and a:b≠c:d.

2. The method for calculating solar radiation according to claim 1, wherein the two pyranometers are installed within two hemispherical glass domes, and wherein, in a space covered by a first glass dome, a measurement value of a first pyranometer installed at a first position within the hemispherical space is denoted by I1, and in a space covered by a second glass dome, a measurement value of a second pyranometer installed at a second position different from the first position within the hemispherical space is denoted by I2, the direct solar transmittance of sunlight passing through the first glass dome towards the first position is denoted by a and the diffuse solar transmittance is denoted by b, and the direct solar transmittance of sunlight passing through the second glass dome towards the second position is denoted by c and the diffuse solar transmittance is denoted by d, and the method calculates the amount of direct solar radiation D and the amount of diffuse solar radiation S at the measurement time by solving the simultaneous equations consisting of equations (1) and (2).

3. A method for calculating solar radiation described in claim 2, wherein the angle of incidence of sunlight related to the amount of direct solar radiation incident on the first position or the second position at the time of measurement is calculated by identifying the optical path of sunlight related to the amount of direct solar radiation and the intersection point on the surface of the first glass dome or the second glass dome based on the azimuth and altitude of the sun, the first position and the second position, and the radius of the first glass dome and the radius of the second glass dome, and the value of the direct solar radiation transmittance a or the direct solar radiation transmittance c is identified based on the angle of incidence.

4. A method for calculating the amount of solar radiation described in claim 2, wherein the diffuse solar transmittance b and the diffuse solar transmittance d are calculated based on sunlight incident from a radiation direction corresponding to a calculation point located on the bottom surface of a hemispherical virtual dome centered on the first position and the second position.

5. A method for calculating solar radiation amount as described in claim 4, wherein: virtual intersection coordinates are calculated, which are the coordinates of the intersection of a line extending vertically upward from one calculation point within the bottom surface and the surface of the virtual dome; the direction of the virtual intersection coordinates as seen from the first position and the second position is defined as a radiation direction, and the included angle between the radiation direction and the normal direction at the intersection of the radiation direction with the surface of the first glass dome and the intersection of the radiation direction with the surface of the second glass dome is calculated; the included angle is defined as the angle of incidence, and a solar transmittance corresponding to one calculation point within the bottom surface is calculated; and the scattered solar transmittance b and the scattered solar transmittance d are calculated by averaging the solar transmittances at all calculation points within the bottom surface.

6. The method for calculating solar radiation described in claim 2, wherein the first position is a position other than the center of the bottom surface of the first glass dome, and the second position is a position other than the center of the bottom surface of the second glass dome and is different from the first position.

7. A method for calculating solar radiation as described in claim 2, wherein the first position and the second position are either: the first position is the center position of the bottom surface of the first glass dome, and the second position is a position other than the center position of the bottom surface of the second glass dome; or the first position is a position other than the center position of the bottom surface of the first glass dome, and the second position is the center position of the bottom surface of the second glass dome.

8. The method for calculating solar radiation according to claim 1, wherein, of the two pyranometers, a first pyranometer is installed outside a hemispherical glass dome and a second pyranometer is installed inside the hemispherical glass dome, the measurement value of the first pyranometer installed at a first position outside the glass dome is I1, and the measurement value of the second pyranometer installed at a second position in the space covered by the glass dome is I2, the values ​​of the direct solar transmittance a and the diffuse solar transmittance b of the sunlight heading toward the first pyranometer are set to 1, the direct solar transmittance c and the diffuse solar transmittance d of the sunlight passing through the glass dome toward the second position are set to 1, and the direct solar radiation D and the diffuse solar radiation S at the measurement time are calculated by solving the simultaneous equations consisting of equations (1) and (2), and the second position is a position other than the center of the bottom surface of the glass dome.

9. A solar radiation calculation device that calculates direct solar radiation D and diffuse solar radiation S at the measurement time using at least one hemispherical glass dome and two pyranometers, wherein the measurement value of a first pyranometer is I1, the measurement value of a second pyranometer is I2, the direct solar radiation transmittance of sunlight heading toward the first pyranometer is a, the diffuse solar radiation transmittance is b, and the direct solar radiation transmittance of sunlight heading toward the second pyranometer is c and the diffuse solar radiation transmittance is d, the measurement value I1 of the first pyranometer and the measurement value I2 of the second pyranometer are expressed by equations (1) and (2): aD+bS=I1... (1) cD+dS=I2... (2) The solar radiation calculation device comprises an arithmetic execution unit that calculates the amount of direct solar radiation D and the amount of diffuse solar radiation S at the measurement time by solving the simultaneous equations consisting of equations (1) and (2), wherein a:b≠c:d.

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