WO2015141659A1

WO2015141659A1 - Pseudo-sunlight irradiation device, photo-irradiation-intensity measurement device, and heat-collector-efficiency measurement method

Info

Publication number: WO2015141659A1
Application number: PCT/JP2015/057835
Authority: WO
Inventors: 芳樹奥原; 友宏黒山; 則武　和人
Original assignee: 一般財団法人ファインセラミックスセンター; 株式会社豊田自動織機
Priority date: 2014-03-20
Filing date: 2015-03-17
Publication date: 2015-09-24
Also published as: JP2015185206A; JP6293540B2

Abstract

A pseudo-sunlight irradiation device (10) having a pseudo-sunlight source (1) for emitting light, a concave mirror (2), an integrator lens (3), and a Fresnel lens (4). The concave mirror (2) point-focuses the light from the pseudo-sunlight source (1) toward the front. The integrator lens (3) is provided to the front of the pseudo-sunlight source (1), and scatters the light which was point-focused by the concave mirror (2) in a quadrangular-pyramid-shaped optical path. The Fresnel lens (4) line-focuses the light incident in the quadrangular-pyramid-shaped optical path from the integrator lens (3). The Fresnel lens (4) is equipped with a collimating lens (4a) for converting the light scattered in a quadrangular-pyramid shape from the integrator lens (3) into a parallel direction, and a cylindrical lens (4b) for line-focusing the light incident from the collimating lens (4a).

Description

Simulated sunlight irradiation device, light irradiation intensity measurement device, heat collection efficiency measurement method

The present invention relates to a simulated sunlight irradiation device, a light irradiation intensity measurement device, and a heat collection efficiency measurement method. Specifically, the present invention relates to a pseudo-sunlight irradiation device used when measuring heat collection efficiency in a receiver (a heat collection tube that converts sunlight into heat) used in a solar heat utilization system. Or it is related with the light irradiation intensity | strength measuring apparatus used in order to measure the irradiation intensity distribution of the light irradiated from the pseudo-sunlight irradiation apparatus. Alternatively, the present invention relates to a heat collection efficiency measurement method for quantitatively measuring the absolute value of the heat collection efficiency in a receiver from the result of measurement using a simulated sunlight irradiation apparatus and a light irradiation intensity measurement apparatus.

The heat obtained by absorbing sunlight is used to heat fluids such as water, steam or oil. Furthermore, solar heat can be used as a thermal energy source or for the generation of an electrical energy source for generating electricity. Moreover, recently, solar heat has been eagerly desired as a countermeasure against global warming or as a clean energy alternative to nuclear power generation. Specifically, in the old days, solar heat is typically used to generate hot water as disclosed in Japanese Patent Laid-Open No. 7-139818. In recent years, solar heat has been used in a technique for generating electricity using high-temperature steam, oil, or the like, as described in Japanese Patent Application Laid-Open No. 2014-31787.

In recent years, in order to collect solar heat more efficiently, a solar heat utilization system that concentrates sunlight at a high magnification to generate a high-temperature heat source has been developed. For example, a solar heat utilization system disclosed in Japanese Patent Application Laid-Open No. 2013-119971 collects sunlight in a linear shape by a parabolic reflector that is a horizontally long concave mirror. A long hollow cylindrical receiver is installed in the line condensing line, and a heat medium is circulated in the pipe of the receiver to recover heat. The receiver is referred to as a heat collecting tube, and converts sunlight into heat to recover thermal energy. Japanese Patent Laid-Open No. 2013-119971 does not show the overall configuration of the solar heat utilization system, but the basic configuration is as follows.

That is, as shown in FIG. 9, the basic mechanism of the solar heat utilization system 100 uses a liquid fluid such as water or oil as a heat medium. The fluid is supplied from the stored tank 101 into the receiver 103. When the fluid flows in the receiver 103, the fluid is heated by receiving sunlight collected by a parabolic reflector (not shown). The heat exchanger 104 extracts heat from the heated fluid and uses it. The fluid is cooled by using heat and returned to the tank 101. This constitutes a circulation path. Reference numeral 105 denotes a pipe through which the fluid flows, and reference numeral 106 denotes a pump that supplies the fluid. Reference numeral 107 denotes a thermometer for measuring the temperature difference between the upstream and downstream of the receiver 103. As in the heat utilization system 110 shown in FIG. 10, there is also a once-through solar heat utilization system that uses a heated fluid as it is without using a heat exchanger. In FIG. 10, the same members as those in FIG. 9 are denoted by the same reference numerals.

In the solar heat utilization system, the heat collection efficiency at the receiver is an extremely important matter. The heat collection efficiency is the ratio of the amount of heat (output energy) that can be recovered to the irradiation intensity (input energy) of the light irradiated to the receiver. The heat collection efficiency at the receiver is directly linked to the efficiency of the entire solar heat utilization system. Japanese Unexamined Patent Application Publication No. 2009-198170 proposes an improved receiver for improving the heat collection efficiency. The receiver has a vacuum double structure, and has a glass tube covering a metal heat collecting tube, and a space evacuated between the heat collecting tube and the glass tube. Furthermore, the surface of the heat collecting tube which becomes the light absorption surface is covered with a selective absorption film.

When developing a receiver with higher heat collection efficiency, select the conditions for improvement so that the effects, performance, quality, etc. are optimal. At this time, it is essential to measure the heat collection efficiency at the receiver. Accurate evaluation of heat collection efficiency can provide basic data essential for optimal design for cost reduction and efficiency improvement of the entire solar heat utilization system. The evaluation method of the heat collecting performance in the receiver is, for example, Document A (J. Pernpeintner, N. Lichtenthaler, B. Schiricke, E. Lupfert, T. Litzke, and W. Minich, "Test benches for the measurement of the optical efficiency parabolic trough receivers using natural sunlight and solar simulator light ", Proceedings of SolarPACES, Perpignan, 2010). Specifically, as shown in FIG. 11, a long elliptic cylindrical mirror 210 having substantially the same left and right length as the receiver 200 is used. A receiver 200 and a plurality of simulated solar light sources 202 are installed on the elliptical cylindrical mirror 210 along two condensing positions. The simulated solar light source 202 irradiates the receiver 200 with simulated sunlight. Water, which is a heat medium, is allowed to flow through the receiver 200 pipe, and the amount of recovered heat is measured from the amount of water temperature rise. A method for measuring the heat collection efficiency shown in FIG. 12 is also disclosed. In the method of FIG. 12, a plurality of pseudo solar light sources 202 are arranged in front of the parabolic reflector 201 and the receiver 200 is irradiated with the pseudo sunlight emitted from the pseudo solar light source 202 using the parabolic reflector 201.

In the method of Document A, the absolute value of the heat collection efficiency cannot be measured because the light irradiation intensity (input energy) to the receiver cannot be quantitatively measured. Therefore, the heat collection performance is evaluated based on a relative comparison of whether the heat recovery amount of the receiver to be measured is larger or smaller than the reference heat recovery amount obtained by the standard receiver. In FIG. 11 and FIG. 12, simulated sunlight from the simulated solar light source 202 is irradiated using only the elliptic cylindrical mirror or the parabolic reflecting mirror 201. Therefore, the incident angle distribution of light with respect to the receiver 200 is not determined randomly. The optical absorption characteristics (transmission / reflection / absorption performance) of the selective absorption film formed on the light absorption surface of the receiver and the glass tube surface for the vacuum double structure are greatly influenced by the incident angle of light. Therefore, the heat collection efficiency also changes depending on the incident angle. That is, in FIG. 11 and FIG. 12, the simulated solar light source cannot be irradiated to the receiver under conditions close to the real environment. As a result, accurate heat collection efficiency cannot be measured.

It is conceivable to use a concave mirror in order to align the incident angle distribution of pseudo sunlight to the receiver to some extent. For example, one concave mirror is installed in one pseudo solar light source 202, and pseudo sunlight is collected from each pseudo solar light source 202. However, in this case, the pseudo-sunlight is spot-concentrated, and a plurality of heat collecting points coexist in the receiver 200. Therefore, the artificial sunlight cannot be irradiated uniformly in the axial direction of the receiver 200. In order to irradiate the pseudo-sunlight as uniformly as possible in the axial direction of the receiver 200, it can be simply considered that a large number of pseudo-sun light sources 202 are arranged closely in parallel. However, in this case, the cost is high, and there is a limit to irradiating the simulated sunlight uniformly.

According to one feature of the present invention, the simulated sunlight irradiation device includes a simulated solar light source that irradiates light, a concave mirror, an integrator lens, and a Fresnel lens. The concave mirror focuses light from the pseudo solar light source forward. The integrator lens is provided in front of the pseudo solar light source, and diffuses the light spot-condensed by the concave mirror into a quadrangular pyramid optical path. The Fresnel lens condenses light incident from the integrator lens through a quadrangular pyramid optical path. The Fresnel lens includes a collimating lens that converts light diffused in a quadrangular pyramid shape from the integrator lens into a parallel direction, and a cylindrical lens that linearly collects light incident from the collimating lens.

Therefore, the light from the pseudo solar light source can be finally condensed and irradiated. Therefore, the light irradiation intensity can be improved by concentrating the light in the circumferential direction of the linear receiver. In addition, the incident intensity and the incident angle distribution of the irradiated artificial sunlight can be constant. Therefore, the heat collection efficiency of the receiver used in the solar heat utilization system can be accurately measured by using the simulated sunlight. As a result, the design of the receiver can be accurately changed. Since the pseudo solar light source collects rays, the condensing part has a certain width. Therefore, the number of installed pseudo solar light sources can be reduced as compared with the conventional one. Moreover, since the rays are condensed, the simulated sunlight can be irradiated with a substantially uniform intensity within a certain range.

Technically, the point light source can be directly focused using only a cylindrical lens. However, since the cylindrical lens has a large aberration between the incident light and the transmitted light, the cylindrical lens has a characteristic that the light collection efficiency is lowered when used at a wide angle of view. In contrast, the collimating lens converts light incident on the cylindrical lens into a parallel direction. Therefore, the collimating lens can suppress a decrease in light collection efficiency due to only the cylindrical lens.

According to another feature of the present invention, a light irradiation intensity measuring device for measuring an irradiation intensity distribution of light from a pseudo solar light source has a sensor, a rotation mechanism, and a slide mechanism. The sensor detects the light irradiation intensity. The rotation mechanism includes a rotation shaft that rotatably supports the sensor. The slide mechanism slides the sensor in the axial direction of the rotation shaft.

Therefore, by sliding the sensor with the slide mechanism, for example, the light irradiation intensity of the entire range of the axial direction of the cylindrical virtual receiver can be measured. At the same time, the light irradiation intensity distribution in the circumferential direction of the virtual receiver can also be measured by rotating the sensor by the rotation mechanism.

Another feature of the present invention relates to a heat collection efficiency measurement method for measuring heat collection efficiency in a receiver used in a solar heat utilization system. In this method, the simulated sunlight irradiating device irradiates the receiver with simulated sunlight, and calculates the output energy from the temperature rise of the fluid circulated inside the receiver. The input energy is calculated from the light irradiation intensity distribution measured by the light irradiation intensity measuring device. The absolute value of heat collection efficiency is quantitatively measured by the ratio of output energy to input energy (output energy / input energy).

Therefore, by using simulated sunlight, it is possible to derive an accurate absolute value of heat collection efficiency and improve the measurement accuracy. If the measurement accuracy of the heat collection efficiency is improved, it is possible to reduce the over-specification design and the risk of failure to achieve the specification of the entire solar heat utilization system using the receiver. This can contribute to efficient and optimal plant design.

It is a perspective view which shows the internal structure of a pseudo sunlight irradiation apparatus. It is a perspective view of the irradiation side of a Fresnel lens. It is a perspective view of the incident side of a Fresnel lens. It is a perspective view of a pseudo solar system. It is a perspective view of another pseudo solar system. It is a perspective view of a light irradiation intensity measuring device. It is a perspective view which shows a light irradiation intensity distribution measurement state. It is a schematic diagram of light irradiation intensity distribution measurement. It is a schematic diagram of a circulation type heat utilization system. It is a schematic diagram of a once-through heat utilization system. It is a schematic diagram of the conventional heat collection efficiency measuring mechanism. It is a schematic diagram of another conventional heat collection efficiency measurement mechanism. It is a measurement result of light irradiation intensity distribution. It is a graph which shows the heat collecting behavior with respect to the flow velocity of the fluid. It is a graph which shows the measurement result of the heat collection efficiency with respect to the flow rate of a fluid.

One embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the simulated sunlight irradiation device 10 includes a simulated solar light source 1, a concave mirror 2, an integrator lens 3, and a Fresnel lens 4. The simulated sunlight irradiation device 10 is configured as a unit in which a plurality of components are installed in one housing 5. An air mass filter 6 is provided between the integrator lens 3 and the Fresnel lens 4. The power supply unit 11 is connected to one (rear side) electrode 1 r of the pseudo solar light source 1. The column 12 supports the other (front side) electrode 1 f of the pseudo solar light source 1 and electrically connects the electrode 1 f and the power supply unit 11.

The pseudo solar light source 1 emits light when it is energized between the

electrodes

1f and 1r by the power supply unit 11. The pseudo solar light source 1 is, for example, a xenon lamp (Xe lamp), a metal halide lamp, or a plasma light source. In particular, the Xe lamp becomes a point light source with high emission intensity, and is excellent in intensity in a wavelength region that can be converted from light to heat. Therefore, the Xe lamp, specifically, the Xe short arc lamp can be suitably used as the pseudo solar light source 1. The simulated solar light source 1 is disposed in the center of the rear end portion of the housing 5, and the axial direction of the simulated solar light source 1 is disposed in parallel with the irradiation direction of the simulated sunlight S or the longitudinal direction of the housing 5.

The power supply unit 11 is, for example, a transformer type dropper power source or a thyristor type switching power source. The dropper power supply is preferable as the power supply unit 11 in terms of high time stability. A switching power supply is preferable as the power supply unit 11 in that it is relatively inexpensive. The axial adjustment mechanism of the pseudo solar light source 1 is preferably provided at the rear end or rear of the housing 5.

The concave mirror 2 is, for example, hemispherical as shown in FIG. The concave mirror 2 is arranged so as to completely cover the light emitting part of the pseudo solar light source 1 from behind. The concave mirror 2 performs point condensing (primary condensing) on the light emitted from the pseudo solar light source 1 in the irradiation direction. The concave mirror 2 is preferably formed of a material having high long-term durability against heat so as to withstand the high temperature from the pseudo solar light source 1. For example, the concave mirror 2 preferably has an aluminum vapor deposition mirror covered with a SiO ₂ protective film.

The integrator lens 3 is a square plate-like glass lens as shown in FIG. The integrator lens 3 is located in front of the concave mirror 2. The integrator lens 3 converts the light collected by the concave mirror 2 into a quadrangular pyramid optical path and makes the light intensity distribution uniform. If the integrator lens 3 is small and the integrator lens 3 is shifted from the point condensing position by the concave mirror 2, the amount of transmitted light is reduced. In order to prevent this phenomenon, the integrator lens 3 is preferably set larger than the size of the point condensing by the concave mirror 2. The area of the integrator lens 3 is smaller than that of the concave mirror 2.

The air mass filter 6 is located in front of the integrator lens 3 as shown in FIG. The air mass filter 6 is larger than the integrator lens 3 and is provided at the center of a rectangular frame. The air mass filter 6 adjusts the light spectrum. For example, when an Xe lamp is used as the simulated solar light source 1, the air mass filter 6 adjusts the light so that the spectral distribution of the light from the simulated solar light source 1 becomes closer to the spectral distribution of sunlight. The air mass filter 6 is preferably configured so as to control the adjustment amount of the spectral distribution. For example, you may have a moving structure which moves the position of the air mass filter 6 in an optical path.

The Fresnel lens 4 is an irradiation lens as shown in FIG. 1 and is installed at the front end of the housing 5. Light from a quadrangular pyramid light path is incident on the Fresnel lens 4 from the integrator lens 3. The Fresnel lens 4 refracts light in a quadrangular pyramid optical path so as to condense it linearly. The Fresnel lens 4 has two functions of a collimating lens that is a point condensing lens and a cylindrical lens that is a line condensing lens. Specifically, as shown in FIGS. 2 and 3, a circular Fresnel shape that functions as a collimating lens 4 a is formed on one surface of the Fresnel lens 4. A linear type Fresnel shape that functions as a cylindrical lens 4 b is formed on the other surface of the Fresnel lens 4. The Fresnel lens 4 is composed of one member. The Fresnel lens 4 is installed in the housing 5 shown in FIG. 1 so that the collimating lens 4a faces the integrator lens 3 and the cylindrical lens 4b faces the irradiation side. Therefore, the light diffused from the integrator lens 3 is refracted by the collimator lens 4a so as to be parallel to the irradiation direction. The parallel light is refracted so as to be linear by the cylindrical lens 4b. Thereby, the simulated sunlight irradiation device 10 emits simulated sunlight S that is line-collected.

It is preferable that the following formulas (1) and (2) are satisfied in order for the pseudo sunlight S to have uniform intensity in the line length direction of the line collection.
fs> 5D (1)
0.5fs <fr <2fs (2)
D is the size of the point light source by the concave mirror 2, that is, the light collection area at the installation position of the integrator lens 3. fs is the focal length of the collimating lens 4a. fr is the focal length of the cylindrical lens 4b. The Fresnel lens 4 is preferably a glass lens in terms of high transmittance, and is preferably a resin lens (for example, made of polymethyl methacrylate resin (PMMA)) in order to increase the size to some extent.

In order to set the focal length of the pseudo sunlight S from the Fresnel lens 4, it is preferable to set the pitch of the unevenness in the lens to 0.1 to 0.5 mm. Distributing the unevenness height (sag amount) in the range of 0.00001 to 0.4mm and the unevenness angle (slope) in the range of 0.001 to 50 ° from the center of the lens toward the lens edge. Is preferred. More preferably, it is preferable to distribute the pitch in the range of 0.2 to 0.4 mm, the sag amount in the range of 0.00002 to 0.2 mm, and the slope in the range of 0.003 to 30 °.

The housing 5 is not particularly limited as long as the various members can be unitized. Simply, as shown in FIGS. 4 and 5, a uniform hollow cylindrical shape from the rear end to the front end may be used. Alternatively, the shape from the rear end to the integrator lens 3 portion may be a cylindrical shape, while the integrator lens 3 to the front end may have a skeleton at each corner and the others open.

When measuring the heat collection efficiency in the receiver 20 of the solar heat utilization system, pseudo

solar systems

40 and 41 are used as shown in FIGS. The simulated solar

light systems

40 and 41 include a frame-shaped gantry 15 and a plurality of simulated solar light irradiation devices 10. Each simulated sunlight irradiation device 10 is installed on the gantry 15 so as to face the receiver 20. Specifically, a plurality of simulated solar light irradiation devices 10 are arranged in a line in the axial direction corresponding to the axial length of the receiver 20. A plurality of rows are installed in the vertical direction, for example, a plurality of rows are arranged on the circumference of a predetermined distance with respect to the axis center of the receiver 20. The simulated sunlight system 40 in FIG. 4 has two rows of simulated sunlight irradiation devices 10, and the simulated sunlight system 41 in FIG. 5 has four rows of simulated sunlight irradiation devices 10. The simulated sunlight irradiation device 10 in each row irradiates the receiver 20 with the simulated sunlight S at a predetermined angle, and the receiver 20 receives the simulated sunlight S from a plurality of angles in the circumferential direction. The direction of the plurality of simulated solar light irradiation devices 10 is set so that the line condensing lines are on the same straight line in the receiver 20.

Next, an apparatus for measuring the irradiation intensity distribution of the pseudo sunlight S on the receiver 20 will be described. The light irradiation intensity measuring device 30 includes a sensor 31, a slide mechanism, and a rotation mechanism as shown in FIG. The sensor 31 detects the irradiation intensity of the simulated sunlight S irradiated from the simulated sunlight irradiation device 10 (see FIG. 1). The slide mechanism slides the sensor 31 in the axial direction of the receiver 20. The rotation mechanism rotates the sensor 31 about the rotation shaft 32. Specifically, the light irradiation intensity measuring device 30 includes a horizontally long scanning stage 33 and a rotating stage 34 slidably installed on the scanning stage 33.

The sensor 31 is a sensor that can measure the light collection density. A variety of sensors can be used as the sensor 31, for example, MEDTHERM's Gurdon radiometer used as a thermal anemometer can be used. As shown in FIGS. 6 and 8, a light receiving unit 31 a that detects the irradiation intensity of the simulated sunlight S is provided at the tip of the sensor 31. A distance L ₁ from the rotating shaft 32 to the light receiving unit 31 a is set to be the same as a distance L ₀ from the central axis of the receiver 20 to be measured to the outer surface of the peripheral wall 20 a to be a light absorbing surface.

The slide mechanism shown in FIG. 6 can use various mechanisms. For example, the slide mechanism may be a rack and pinion mechanism having a rack provided on the scanning stage 33 and a pinion provided on the rotary stage 34. The pinion rotates on the rack by being rotated by, for example, a motor or the like. Alternatively, the slide mechanism may include a rail provided on the scanning stage 33 and an air cylinder, a hydraulic cylinder, or the like that slides the rotary stage 34 on the rail. Alternatively, the slide mechanism may include a worm gear provided on the scanning stage 33 and a spur gear provided on the rotary stage 34. The worm gear may be rotated by a motor. The spur gear is provided on the rotary stage 34 so as to freely rotate and is meshed with the worm gear. Alternatively, the slide mechanism may have a configuration in which the rotary stage 34 is slid by a timing belt or a chain stretched over the scanning stage 33.

The rotary stage 34 has two props 38 that stand up as shown in FIG. 6 and a rotary shaft 32 that is rotatably supported between the props 38. A sensor 31 is provided on the rotation shaft 32, and the sensor 31 rotates about the rotation shaft 32. As a rotation mechanism of the sensor 31, a gear box 35 and a motor box 36 are provided. The gear box 35 is connected to one end of the rotating shaft 32 and attached to the upper part of the rotating stage 34. The motor box 36 is provided below the rotary stage 34 and accommodates the motor. The motor and the gear in the gear box 35 are connected by a chain 37, and the rotating shaft 32 rotates around the axis by the output of the motor. The motor is located away from the line collector. Therefore, it is possible to prevent the periphery of the motor from being heated by light and causing the motor to malfunction. The sensor 31 is connected to the data processing device via a cable (not shown). Electric power is supplied to the motor via a cable (not shown).

When measuring the light collection efficiency in the receiver 20 using the light irradiation intensity measuring device 30, as shown in FIGS. 5 to 7, the light irradiation intensity measuring device so that the sensor 31 is located at the position where the receiver 20 is installed. 30 is installed. Specifically, the rotation shaft 32 of the sensor 31 is positioned on the central axis of the virtual receiver 20. When measuring the light collection efficiency, the sensor 31 is rotated while being slid. Specifically, the sensor 31 is rotated about the rotation shaft 32 while sliding left and right within the range of the axial length of the virtual receiver 20. The distance L ₁ from the rotating shaft 32 to the light receiving unit 31 a is the same as the distance L ₀ from the central axis of the virtual receiver 20 to the outer surface of the peripheral wall 20 a. Therefore, the light receiving unit 31 a moves along the peripheral wall 20 a that is a light absorption surface of the virtual receiver 20. By measuring the relationship between the sensor position (axial position / rotation angle) and the light irradiation intensity at each position, the irradiation intensity distribution of the pseudo sunlight S that the receiver 20 will receive can be measured.

The receiver 20 has a long hollow cylindrical shape as shown in FIGS. A fluid that is a heat medium flows through the pipe of the receiver 20. The fluid is heated by the simulated sunlight S irradiated on the receiver 20, thereby recovering thermal energy from the sunlight. Therefore, the receiver 20 is also referred to as a heat collecting tube.

The input energy per unit time to the receiver 20 can be calculated by integrating the light irradiation intensity distribution obtained by the light irradiation intensity measuring device 30 with respect to the irradiation area. The amount of heat recovered by the receiver 20 is calculated by measuring the amount of fluid in the receiver 20 heated by simulated sunlight, that is, the temperature rise at the inlet and outlet of the receiver 20, as in the conventional method. The recovered heat quantity ΔQ (kW = kJ / s) per unit time is the output energy per unit time obtained from the receiver 20, and is obtained by Expression (3).
ΔQ = CpΔTρν (3)
ΔT (K) is a temperature difference between the liquid at the inlet and the outlet of the receiver 20. Cp (kJ / kgK) is the specific heat at the fluid test temperature, ρ (kg / m ³ ) is the density, and ν (m ³ / s) is the flow rate.

Water, steam, oil, etc. can be used as the fluid as the heat medium. The heat medium can be selected depending on the temperature zone of the receiver 20 to be measured. By adjusting the temperature of the fluid by heating the fluid before entering the receiver 20, the temperature zone in the receiver 20 can be arbitrarily set.

The heat collection efficiency (= output energy / input energy) can be derived as a ratio at which the calculated output energy with respect to the input energy obtained by the light irradiation intensity measuring device 30 is obtained.

Next, a light irradiation distribution measurement test using the light irradiation intensity measuring device 30 will be described. As a simulated solar light source 1 for the test, the diameter of the concave mirror 2 was set to 380 mm, and the focal length between the concave mirror 2 and the integrator lens 3 (primary focusing point) was set to about 700 mm. A lens made of polymethyl methacrylate resin was used as the Fresnel lens 4. The lens integrally includes a collimating lens having a point condensing distance fs = 800 mm and a cylindrical lens having a line condensing distance fr = 1100 mm. A Xe lamp having a rated output of 5 kW was used as the simulated solar light source 1. A trough-type receiver having a heat collecting tube having an axial length of 4.0 m and a diameter of 70 mm was assumed as the receiver 20. Two simulated sunlight irradiation devices 10 were used as the

simulated sunlight system

40, and 10 simulated sunlight irradiation devices 10 were arranged in one row.

As the receiver 20, a trough receiver having an axial length of 4.0 m and a diameter of 70 mm was assumed. As the light irradiation intensity measuring device 30, the scanning range was set to 4.8 m, and the scanning rotation range was set to ± 90 °. As a sensor, a MEDHERRM thermal anemometer “Gardon radiometer” was used. The distance between the light receiving part of the sensor and the rotation axis was set to 35 mm, which is the same as the radius of the 70 mm tube. Optical axis adjustment and light irradiation intensity distribution were measured using the light irradiation intensity measuring device 30 under the above conditions. At the time of measuring the light irradiation intensity, most of the pseudo sunlight S is not measured by the light receiving unit 31a of the sensor 31. Therefore, a water-cooled plate coated with a black body paint is provided at a position opposite to the simulated sunlight system 40 with the light irradiation intensity measuring device 30 interposed therebetween. The water cooling plate can absorb the simulated sunlight S and release heat by water circulation.

FIG. 13 shows a two-dimensional distribution map of the light irradiation intensity in the axial direction and the circumferential direction obtained by using the light irradiation intensity measuring device 30 set as described above. From the results of FIG. 13, the on-axis direction line in the horizontal position or angle 0 ° of the virtual receiver, up to 37.7kW / m ^2, minimum 28.2kW / m illuminance distribution in the range of ^2, unevenness ± 14 Within 5%. The illuminance is distributed so as to decrease as the angle from the horizon increases from 0 ° to ± 90 °. When the average value of the light irradiation intensity is obtained from the two-dimensional map, it is 18.1 kW / m ² . The two-dimensional distribution map indicates the light irradiation intensity in the half surface of the virtual receiver. The light irradiation intensity obtained from sunlight with a trough-type receiver (aperture: 5.77 m) was 52.5 kW / m ² . Therefore, it has been found that the apparatus using the above-described pseudo solar light source 1 emits about 35% of the actual sunlight.

As a reference, it can be estimated that the light irradiation intensity emitted by the DLR EliREC is 5.1 kW / m ^{2 on} average from a heat collection amount of 4 kW and a receiver efficiency of 90%. It can be seen that the apparatus using the pseudo solar light source 1 described above can achieve a light irradiation intensity of about 3.6 times that of DLR. Since the apparatus using the above-described pseudo solar light source 1 has a light irradiation intensity based on the circumferential surface of 18.1 kW / m ² , the light irradiation intensity based on a rectangular cross-sectional area of 4 m × 70 mm diameter is 28.5 kW / m ^2. Can be converted to m ² .

Based on the measurement result of the light illuminance distribution, a test was performed to calculate the absolute value of the heat collection efficiency of the receiver under measurement. In this test, a receiver having a shaft length of 4.0 m, a diameter of 70 mm, and a SUS heat collecting tube covered with a glass tube having a diameter of 125 mm was used. A selective absorption film having an absorptivity in the sunlight wavelength region of 83% and an emissivity in the infrared region of 5% is provided on the surface of the heat collecting tube. The vacuum tube was evacuated between the heat collecting tube and the glass tube, and after the pressure was reduced to 0.5 Pa or less by bellows portion baking, simulated sunlight was irradiated under the same conditions as the light irradiation distribution measurement test.

As the method of flowing the heat medium for the test, the circulation method shown in FIG. 10 or the once-through method shown in FIG. 11 can be used. In this test, a circulation system was adopted, and a static mixer having a length of about 300 mm was added near the outlet of the receiver. The static mixer has seven plates that shield about 3/2 of the cross section inside, and the seven plates are alternately arranged up and down. Therefore, the heat medium passing through the static mixer is stirred so that the heat becomes uniform by meandering up and down. The heat medium was water.

流速 Change the flow rate of water, which is the heat medium, from 42L / min to 10L / min step by step. For example, the flow rate of water was changed by adjusting the frequency of the input current of the pump with an inverter. The temperature difference at the receiver inlet / outlet at each flow rate was measured, and the water flow rate and temperature behavior are shown in FIG.

From the result of FIG. 14, the water temperature difference at the receiver inlet / outlet tends to increase as the water flow rate becomes slower. When the water flow rate is 10 L / min, the maximum water temperature difference is 8.8 ° C.

14 Calculate the amount of recovered heat (output energy) from equation (3) based on the temperature difference at each flow rate in the results of FIG. The heat collection efficiency is derived based on the recovered heat quantity, and the relationship between the heat collection efficiency and the water flow rate is shown in FIG. From the result of FIG. 15, it was clarified that the heat collection efficiency can be maintained almost constant without greatly depending on the water flow velocity. That is, since almost the same heat collection efficiency is obtained at any flow rate, it is confirmed that stable temperature measurement and light irradiation with small time fluctuation can be performed.

FIG. 15 shows the theoretical efficiency expected from the optical characteristics by dotted lines. From FIG. 15, it was found that the heat collection efficiency obtained in this example was in good agreement with the theoretical efficiency. That is, it was confirmed that the heat collection efficiency can be accurately measured by the apparatus and method of this example. The theoretical efficiency from the optical characteristics can be calculated from the absorption spectrum of the selective absorption film of the receiver and the transmittance of the glass tube having a vacuum double structure, and was 76.4% in this test.

As described above, the simulated solar light irradiation device 10 is a unit in which a plurality of members are installed in one housing 5. Thereby, the simulated solar light irradiation apparatus 10 can be easily installed.

When the two Fresnel lenses 4 are installed for the light from the integrator lens 3, the reflection loss of light is integrated on each lens surface (interface with air). For this reason, there is a limit in efficiently collecting lines. As shown in FIGS. 2 and 3, the Fresnel lens 4 is a single member, and a Fresnel shape that functions as a collimating lens 4 a is formed on one surface of the Fresnel lens 4. A Fresnel shape that functions as the cylindrical lens 4b is formed on the other surface. In other words, the collimating lens 4a and the cylindrical lens 4b are formed as a single lens. Thus, collimated light can be created within the lens thickness. Thereby, the number of installed lenses can be reduced, and the reflection loss of the simulated sunlight S can be reduced. As a result, the irradiation intensity of the pseudo sunlight S can be improved. In addition, since the Fresnel lens 4 can have the same shape as an aspheric lens, aberration correction can be performed on a single surface. Further, in the Fresnel lens 4, the optical path lengths in the optical elements near the optical axis and near the off-axis are substantially the same. Therefore, there is a merit that the optical element is hardly affected by absorption.

Examples of the light source for irradiating the pseudo sunlight S include a xenon lamp (Xe lamp), a metal halide lamp, a plasma light source, and the like. However, since the plasma light source has a large light emitting area and does not become a point light source, there remains a problem in condensing light. In addition, the metal halide lamp has a high intensity on the short wavelength side in the ultraviolet region, and there remains a problem in terms of simulating the sunlight spectrum. Therefore, the pseudo solar light source is preferably an Xe lamp.

If the pseudo solar light source is an Xe lamp, the air mass filter 6 can adjust the spectral distribution of light. Therefore, when the pseudo solar light source is an Xe lamp, if the air mass filter 6 is provided between the integrator lens 3 and the Fresnel lens 4, the pseudo solar light S can be brought close to the actual solar spectrum distribution. .

As shown in FIGS. 5 to 7, the receiver 20 is installed in the simulated

solar system

40, 41, and the heat collection efficiency of the receiver 20 is measured. Instead of the receiver 20, the light irradiation intensity measuring device 30 is incorporated in the

simulated sunlight systems

40 and 41, and the light irradiation intensity distribution of the simulated sunlight S irradiated on the receiver 20 is measured. The light irradiation intensity measuring device 30 can measure the light irradiation intensity of the entire range of the virtual receiver in the axial direction by sliding the sensor 31 to the left and right by the slide mechanism. At the same time, the light irradiation intensity distribution in the circumferential direction in the virtual receiver can also be measured by rotating the sensor 31 by the rotation mechanism. The distance from the rotating shaft 32 to the light receiving unit 31a is set to be the same as the distance from the central axis of the receiver 20 to the peripheral wall 20a. Therefore, since the light receiving unit 31a rotates at a position corresponding to the peripheral wall 20a of the receiver 20, the light irradiation intensity distribution in the receiver 20 can be accurately measured.

As described above, since the light irradiation intensity to the receiver 20 can be quantitatively measured, the input energy to the receiver 20 can be known. The output energy can be calculated from the temperature rise of the fluid that is radiated into the receiver 20 by irradiating the receiver 20 with the simulated sunlight S. Therefore, the heat collection efficiency of the receiver 20 can be derived as an absolute value from the input energy and the output energy. As described above, this embodiment is not a conventional relative performance evaluation method, and can obtain absolute conversion efficiency. Specifically, in the conventional evaluation method, the information is whether the heat recovery amount of the receiver to be measured is relatively large or small with respect to the heat recovery amount of the standard receiver. Therefore, it was not easy to apply to the plant design of solar thermal utilization system. In contrast, in this embodiment, the absolute value of the heat collection efficiency of the receiver 20 is known. Thereby, the efficiency in the whole solar heat utilization system to which the receiver 20 is applied can be derived. Furthermore, the heat collection efficiency of the receiver 20 is extremely useful information even in the process of designing the total extension of the receiver 20 necessary for obtaining the total amount of energy required in the solar heat utilization system. These effects make it possible to optimally design the entire solar heat utilization system and avoid the risk of excessive specification design and specification failure. Thus, cost reduction and efficiency improvement in the entire system can be achieved.

Although the embodiments of the present invention have been described with reference to the above structure, it is obvious to those skilled in the art that many alternations, improvements, and changes can be made without departing from the object of the present invention. Accordingly, aspects of the invention may include all alterations, modifications, and changes that do not depart from the spirit and scope of the appended claims. For example, the form of the present invention is not limited to the special structure, and can be modified as follows.

For example, the simulated sunlight irradiation device 10 may have the air mass filter 6 or may not have the air mass filter 6. As shown in FIG. 1, the pseudo solar light source 1 may be provided at the rear end of the housing 5, the rear portion near the rear end, and the center. The Fresnel lens 4 may be provided at the front end of the housing 5, the front portion near the front end, and the central portion. As shown in FIG. 1, the concave mirror 2 may be hemispherical, or may have other shapes capable of focusing on one point, such as a bowl shape, a partial spherical shape, a parabolic curved surface shape, and various curved surface shapes.

As shown in FIG. 2, the collimating lens 4a of the Fresnel lens 4 bends the light diffused in a quadrangular pyramid shape from the integrator lens 3 in a parallel direction. For example, the collimating lens 4a may refract the light diffused in a quadrangular pyramid shape so that it is parallel to the quadrangular prism shape, that is, completely parallel, or refracted so as to be parallel or substantially parallel. Also good. For example, the light may be bent so as to reduce the diffusion angle, or the light may be bent so as to collect light with a small angle.

The light irradiation intensity measuring device 30 is used when measuring the light irradiation intensity distribution in the cylindrical receiver 20 as shown in FIGS. Alternatively or in addition, the light irradiation intensity distribution on the surface of the square plate may be calculated from the detection result as described above, and may be used when measuring the light irradiation intensity distribution in the receiver having the surface of the square plate. . Or you may utilize when measuring the light irradiation intensity distribution in the receiver of another shape from a detection result.

As shown in FIG. 6, the distance between the center of the rotating shaft 32 and the light receiving portion 31a is fixed to a predetermined distance. Instead of this, the light irradiation intensity measuring device 30 may have a configuration in which the distance between the axis center of the rotating shaft 32 and the light receiving unit 31a can be changed. For example, the sensor 31 may be attached to the rotary shaft 32 so as to be movable in the radial direction.

Claims

A simulated solar irradiation device,
A simulated solar light source that emits light;
A concave mirror for focusing the light from the pseudo solar light source forward;
An integrator lens that is provided in front of the pseudo-solar light source and diffuses the light focused by the concave mirror into a quadrangular pyramid optical path;
A Fresnel lens that linearly collects light incident from the integrator lens through a quadrangular pyramid optical path;
The Fresnel lens includes pseudo-sunlight including a collimating lens that converts light diffused in a quadrangular pyramid shape from the integrator lens into a parallel direction and a cylindrical lens that linearly collects light incident from the collimating lens. Irradiation device.
The simulated solar light irradiation device according to claim 1,
A pseudo-sunlight irradiation device in which the concave mirror is hemispherical.
The simulated solar light irradiation device according to claim 1 or 2,
A simulated solar light irradiation device in which the simulated solar light source, the concave mirror, the integrator lens, and the Fresnel lens are mounted on a housing.
The simulated solar light irradiation device according to claim 3,
A simulated solar light irradiation device in which the simulated solar light source is provided at a rear end of the housing.
The pseudo-sunlight irradiation device according to claim 3 or 4,
The simulated sunlight irradiation apparatus in which the Fresnel lens is provided at the front end of the housing.
The simulated solar light irradiation device according to any one of claims 1 to 5,
The said collimating lens is a pseudo-sunlight irradiation apparatus comprised by the Fresnel shape formed in one surface of the said Fresnel lens.
The pseudo-sunlight irradiation device according to any one of claims 1 to 6,
The said cylindrical lens is a pseudo-sunlight irradiation apparatus comprised by the Fresnel shape formed in one surface of the said Fresnel lens.
The pseudo-sunlight irradiation device according to any one of claims 1 to 7,
The collimating lens and the cylindrical lens are pseudo-sunlight irradiation devices formed as a single lens.
The pseudo-sunlight irradiation device according to any one of claims 1 to 8,
The simulated solar light irradiation device, wherein the simulated solar light source is a xenon (Xe) lamp.
The simulated solar light irradiation device according to claim 9,
A pseudo-sunlight irradiation device in which an air mass filter is provided between the integrator lens and the Fresnel lens.
A light irradiation intensity measuring device for measuring an irradiation intensity distribution of light from a pseudo solar light source,
A sensor for detecting the light irradiation intensity;
A rotation mechanism including a rotation shaft that rotatably supports the sensor;
A light irradiation intensity measuring device having a slide mechanism for sliding the sensor in the axial direction of the rotation shaft.
The light irradiation intensity measuring device according to claim 11,
The said light irradiation intensity measuring apparatus is a light irradiation intensity measuring apparatus used when measuring the heat collection efficiency in the cylindrical receiver used with a solar-heat utilization system.
The light irradiation intensity measuring device according to claim 12,
The light irradiation intensity measuring apparatus set so that the distance between the axis center of the rotating shaft and the light receiving part of the sensor is the same as the distance from the central axis of the receiver to the outer peripheral surface of the receiver.
A heat collection efficiency measurement method for measuring heat collection efficiency in a receiver used in a solar heat utilization system,
Output energy calculated from a temperature rise of a fluid that irradiates the receiver with simulated sunlight by the simulated sunlight irradiation device according to any one of claims 1 to 10 and circulates in the receiver, and The absolute value of the heat collection efficiency is quantitatively measured by the ratio (output energy / input energy) to the input energy calculated from the light irradiation intensity distribution measured by the light irradiation intensity measuring device according to any one of 11 to 13 To measure heat collection efficiency.