Pyranometer

Abstract

The present invention relates to a pyranometer intended for the meteorological, energy and environmental industrial sector and designed to measure incident solar radiation on the Earth's surface with high accuracy. This device measures direct, diffuse and reflected radiation by means of a matrix of solar sensors distributed in a horizontal plane and a pattern of shadows. The design without movable pieces ensures high durability and reliability, avoiding degradation due to prolonged exposure to the sun and obtaining a permanent pattern of shadows that can be obtained from sheet metal by stamping. The invention discloses a case that houses light sensors, sensors, and internal control, calculation and communication modules, making it possible to send data via the Internet or Modbus systems and allowing for remote updates. Optionally, it includes a module for capturing albedo light. The robust, compact and suitable design of the invention for industrial applications in solar plants, meteorological studies and energy management ensures accurate results and continuous optimisation.

Description

[0001] PYRANOMETER

[0002] OBJECT OF THE INVENTION

[0003] The present invention relates to a pyranometer, a meteorological instrument used to accurately measure incident solar radiation on the Earth's surface. This sensor is designed to measure solar radiation flux density (watts per square meter) over a 180-degree field.

[0004] BACKGROUND OF THE INVENTION

[0005] Depending on how solar radiation affects, we have three types of it:

[0006] 1. Direct radiation: This is radiation that arrives directly from the Sun without having undergone any modifications in its trajectory. It is characterized by projecting a defined shadow on opaque objects that intercept it. This type of radiation is the most abundant on a sunny day, easily exceeding 80% of the total radiation from the sun, while on a cloudy day it may only be 50% or less.

[0007] 2. Diffuse radiation: This radiation originates from the atmosphere, that is, from the dispersion of some of the solar radiation as it hits the atmosphere. On the sunniest days, with no cloud cover, this type of radiation can account for approximately 15% of the total, but on cloudy days when the amount of direct radiation is reduced, this type of radiation increases considerably.

[0008] 3. Reflected radiation: This radiation bounces off the Earth's surface. The amount of this type of radiation depends on the surface's reflection coefficient, or "albedo." Only vertical (perpendicular to the Earth's surface) or inclined surfaces receive this radiation, since it is impossible for a reflected ray from the ground to strike a horizontal surface facing upward. Currently, pyranometers can measure both direct and diffuse radiation and include moving parts similar to solar trackers, with the associated complexity.

[0009] Currently, there is only one pyranometer on the market that lacks such moving parts (which is passive), and comprises a sensor array and a shadow pattern arranged on the sensor array to ensure that, at any given time with natural light, at least one of the sensors receives direct solar radiation and at least one other of them is completely under the shadow generated by the shadow pattern to receive diffuse radiation. It is described in patent document EP1012633. However, the shadow pattern described in this document is described or parameterized primarily by the result to be obtained, and not by its own physical characteristics, which makes it difficult or directly impedes the expert from materializing specific embodiments. Furthermore, it proposes creating the shadow pattern by applying an opaque mask, basically materialized by paint applied over a translucent cover.This configuration, exposed to the sun for long periods of time, can progressively degrade the opaque layer and the pattern may become less effective.

[0010] DESCRIPTION OF THE INVENTION

[0011] The pyranometer of the invention is of the type comprising a sensor array and a shadow pattern arranged on the sensor array to ensure that, at any time in natural light, at least one of the sensors receives direct solar radiation and at least one other of them is completely under the shadow generated by the shadow pattern, and where according to the invention:

[0012] -the sensor array comprises nine circular sunlight sensors of equal optical diameter A (the functionally operative diameter for capturing light, eliminating edges of encapsulations or similar), arranged in a horizontal plane, comprising eight first sensors arranged in the form of a circumference and angularly separated by 45 degrees, and a second sensor arranged in the geometric center of the circumference formed by the centers of the eight first sensors, and

[0013] -where the shadow pattern comprises a plate in the form of a circular crown, arranged over the sensors and spaced parallel to the plane containing them; comprising an outer base ring on which the plate is supported by arms; and comprising four extensions on the inside of the plate that completely cover four of the first eight sensors in normal projection.

[0014] This creates a permanent shadow pattern that does not degrade over time and is also easily obtained from sheet metal by stamping.

[0015] DESCRIPTION OF THE DRAWINGS

[0016] Figure 1.- Shows a perspective view of the shadow pattern of the pyranometer of the invention, where the circular crown-shaped plate is supported by four arms.

[0017] Figure 2.- Shows an elevation view of the shadow pattern of the pyranometer of the invention, where the plate in the form of a circular crown is supported by eight arms.

[0018] Figure 3.- Shows a diametrically sectioned view of the shadow pattern in Figure 2.

[0019] Figure 4a.- Shows a plan view of the shadow pattern in Fig. 2, placed over the light sensors, where the sensors are silhouetted for better appreciation.

[0020] Figure 4b.- Shows a plan view of the plate that carries the sensors in figure 4a, removing the shadow pattern to better appreciate its arrangement, as well as an enlarged detail showing the optical diameter of the sensors.

[0021] Figure 5.- Shows a plan view of the shadow pattern placed over the light sensors, where the sensors hidden under the shadow pattern are not silhouetted.

[0022] Figure 6.- Shows a sectioned detail of the pyranometer, to appreciate other internal components.

[0023] Figure 7 shows a view of the pyranometer of the invention, placed on a support, and with an albedo light sensor. PREFERRED EMBODIMENT OF THE INVENTION

[0024] The pyranometer (1) of the invention (see fig. 6 and 7), is of the type comprising (go now to figs. 1 to 5) a matrix (2) of sensors and a shadow pattern arranged on the matrix (2) of sensors to ensure that, at any time with natural light, at least one of the sensors receives direct solar radiation and, at least, another of them is completely under the shadow generated by the shadow pattern, and where according to the invention:

[0025] -the sensor array (2) comprises nine circular sunlight sensors (20, 21) of equal optical diameter A, arranged in a horizontal plane (4), comprising eight first sensors (20) arranged in the form of a circumference and angularly separated by 45 degrees, and a second sensor (21) arranged at the geometric center of the circumference (20a) (see fig. 4b) formed by the centers of the eight first sensors (20), and

[0026] -where the shadow pattern comprises a plate (31) in the form of a circular crown, arranged above the sensors (20, 21) and spaced from them parallel to the plane (4) (see fig. 3); comprising an outer base ring (33) for mounting on which the plate (31) is supported by means of arms (34) spaced angularly equidistant from each other, and comprising four extensions (34a) on the inside of the plate (31) that are normally and completely covering four of the first eight sensors (20), as seen in figure 4a.

[0027] In the most preferred materialization, where the best functioning of the shadow pattern has been found, it is true that:

[0028] -the circumference (20a) containing the centers of the first eight sensors (20) has a geometric radius of 3.75 / 1 in relation to the optical diameter A of the sensors (20, 21);

[0029] -the plate (31) in the form of a circular crown, has an internal diameter of 7.26 / 1 in relation to the optical diameter A of the sensors (20, 21) and an external diameter of 14.78 / 1 in relation to the optical diameter A of the sensors (20, 21), and is arranged at a height 0.75 / 1 with respect to the sensors (20, 21) in relation to the optical diameter A of said sensors (20, 21); and

[0030] -the projection of the extensions (34a) on the inside of the plate (31) is 0.6 / 1 in relation to the optical diameter A of the sensors (20, 21).

[0031] For its part, the base ring (33) ideally has in this case an inner diameter of 15.29 / 1 in relation to the optical diameter A of the sensors (20, 21), and the arms (34) have an angular amplitude of 20 sexagesimal degrees. In addition, it is preferred that the optical diameter A of the sensors (20, 21) be 2 millimeters, which is a commercial value and results in reduced dimensions of the assembly.

[0032] Additionally, it has been planned that the plate (31) in the form of a circular crown may comprise a curved notch (31a) next to one of the arms, with a radius of 1.4 / 1 in relation to the optical diameter A of the sensors (20, 21), in whose projection, a bubble level (100) is arranged, all so that the installation of the pyranometer is parallel to the plane of the earth and allows the results obtained to be those that the calibration of the pyranometer requires to have total reliability in the measurement.

[0033] The assembly is installed in a levelable housing (5) (see figs. 6 and 7) with a first transparent or translucent window (50) matching the sensors and the shadow pattern, to protect the components from atmospheric agents, but allow sunlight to enter. In addition, inside this housing (5) the following will preferably be arranged (see fig. 6): - a light sensor module (6) (on a first PCB board), where the sensors (20, 21) and the analog instrumentation are fixed to accommodate the signals from the radiation sensors,

[0034] -a radiation control and calculation module (7) (on a second PCB board), which also comprises a Modbus modulator (70) and an analog output signal modulator (71), for sending data via Modbus and the analog output signals, and

[0035] -a communications module (8) (on a third PCB board), with a link (80) for sending data via the Internet. These three boards are connected and placed inside the housing.

[0036] The possible optional arrangement of an albedo light collection module (9) (that reflected by the ground) has been envisaged, comprising (see fig. 7) a third sensor (90), a second casing (91), a second transparent or translucent window (92), means of fixing to the casing (5), and means of connection to the control module (basically a connector).

[0037] Learning and OTA: The pyranometer features cellular communications, allowing it to periodically send data to a server. Once sufficient units have been deployed and a significant amount of data is available, this data can be analyzed and measurements improved. OTA or FOTA (Firmware Over The Air) is a common practice in many IoT devices that allows the microprocessor to be reprogrammed via its communications network. This allows potential programming errors to be resolved or the program to be improved remotely without having to physically reprogram the pyranometer. Therefore, the housing includes external connectors (55) for configuration connections and / or data exchange.

[0038] Having sufficiently described the nature of the invention, it is indicated that the description thereof and its preferred embodiment must be interpreted in a non-limiting manner, and that it covers all possible embodiments that may be deduced from the content of this specification and the claims.

Claims

1.-Pyranometer (1), of the type comprising a matrix (2) of sensors and a shadow pattern arranged on the matrix (2) of sensors to ensure that, at any time with natural light, at least one of the sensors receives direct solar radiation and at least one of them is completely under the shadow generated by the shadow pattern, characterized by: -the sensor array (2) comprises nine circular sunlight sensors (20, 21) of equal optical diameter A, arranged in a horizontal plane (4), and comprising eight first sensors (20) arranged in the form of a circumference and angularly separated by 45 degrees, and a second sensor (21) arranged in the geometric center of the circumference (20a) formed by the centers of the eight first sensors (20), and -where the shadow pattern comprises a plate (31) in the form of a circular crown, arranged on the sensors (20, 21) and spaced from them parallel to the plane (4); comprising an outer base ring (33) on which the plate (31) is supported by means of arms (34), and comprising four extensions (34a) on the inside of the plate (31) that are normally and completely covering four of the first eight sensors (20). 2.-P¡ranometer (1) according to claim 1, where: -the circumference (20a) containing the centers of the first eight sensors (20) has a geometric radius of 3.75 / 1 in relation to the optical diameter A of the sensors (20, 21); -the plate (31) in the form of a circular crown, has an internal diameter of 7.26 / 1 in relation to the optical diameter A of the sensors (20, 21) and an external diameter of 14.78 / 1 in relation to the optical diameter A of the sensors (20, 21), and is arranged at a height 0.75 / 1 with respect to the sensors (20, 21) in relation to the optical diameter A of said sensors (20, 21); and -the projection of the extensions (34a) on the inside of the plate (31) is 0.6 / 1 in relation to the optical diameter A of the sensors (20, 21) 3.-P¡ranometer (1) according to claim 2, where the base ring (33) has an internal diameter of 15.29 / 1 in relation to the optical diameter A of the sensors (20, 21), and the arms (34) have an angular amplitude of 20 sexagesimal degrees. 4.-P¡ranometer (1) according to any of the preceding claims, wherein the diameter optical A of the sensors (20, 21) is 2 millimeters. 5.-P¡ranometer (1) according to any of the previous claims, wherein the plate (31) in the form of a circular crown comprises a curved notch (31a) next to one of the arms with a radius of 1,4 / 1 in relation to the optical diameter A of the sensors (20, 21), in whose projection, a bubble level (100) is arranged. 6.-P¡ranometer (1) according to any of the preceding claims, comprising a housing (5) with a first transparent or translucent window (50) coinciding with the sensors and the shadow pattern. 7.-P¡ranometer (1) according to claim 6, where inside the casing (5) the following are arranged: -a light sensor module (6), where the sensors (20, 21) are fixed, -a control and calculation module (7), which also comprises a Modbus modulator (70) and an analog output signal modulator (71), and -a communications module (8), with a link (80) for sending data via the Internet. 8.-P¡ranometer (1) according to claim 6 or 7, comprising an albedo light collection module (9), which comprises a third sensor (90), a second housing (91), a second transparent or translucent window (92), means for fixing to the housing (5), and means for connecting to the control module. 9.-P¡ranometer (1) according to any of claims 6 to 8, wherein the housing (5) comprises external connectors (55).

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