SYSTEMS AND METHODS FOR CONTROL OF A SOLAR POWER TOWER USING INFRARED THERMOGRAPHY

• US 20100006087A1
• Filed: 07/09/2009
• Published: 01/14/2010
• Est. Priority Date: 07/10/2008
• Status: Active Grant

• Current Assignee: BrightSource Industries (Israel) Ltd (BrightSource Energy)
• Original Assignee: BrightSource Industries (Israel) Ltd (BrightSource Energy)
• Inventors: Hayut, Rotem, Aumann, Ziv, GILON, YOEL, Chernin, Ophir, Franck, Dan, Kroyzer, Gil, Kroizer, Israel, Goldwine, Gideon
• Granted Patent: US 8,931,475 B2
• Time in Patent Office: Days
• US Class Current: 126/572
• CPC Class Codes: F24S 20/20 Solar heat collectors for receiving concentrated solar energy, e.g. receivers for solar power plants
• CPC Class Codes: F24S 23/70 with reflectors
• CPC Class Codes: F24S 50/20 for tracking
• CPC Class Codes: F24S 50/40 responsive to temperature
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers
• CPC Class Codes: Y02E 10/47 Mountings or tracking

Abstract

Systems and methods for directly monitoring energy flux of a solar receiver in a solar energy-based power generation system include measuring infrared radiation emanating from the solar receiver. Such measurement can be achieved using one or more infrared thermography detectors, such as an IR camera. Resulting thermal data obtained by the imaging can be used to determine energy flux distribution on the receiver. A user or a system controller can use the determined flux distribution to adjust heliostat aiming to achieve a desired operation condition. For example, heliostats can be adjusted to achieve a uniform energy flux distribution across the external surface of the receiver and/or to maximize heat transfer to a fluid flowing through the receiver within system operating limits.

Claims

1. A solar energy collection system comprising:

a plurality of heliostats;

a solar receiver which receives on an external surface thereof solar radiation reflected from the plurality of heliostats, the receiver including a plurality of tubes for conveying a fluid therethrough, external surfaces of the tubes forming at least a portion of the receiver external surface, the external surfaces of the tubes transmitting energy from the reflected solar radiation received thereon to the conveyed fluid;

a plurality of thermal imaging devices which detect infrared radiation emanating from the receiver external surface and provide first temperature signals indicative of a temperature at a location on the receiver external surface,

each thermal imaging device having a plurality of pixels, the external surface of each of the tubes being imaged by at least one of the plurality of pixels,

fields of view of the thermal imaging devices overlapping such that at any given time each location on the receiver external surface is imaged by at least one of the thermal imaging devices which does not look into the sun;

a weather station which measures instantaneous weather data at a location of the solar energy collection system and transmits the measured weather data to at least the plurality of thermal imaging devices, the thermal imaging devices adjusting the first temperature signals based on the transmitted weather data; and

a controller which computes incoming solar energy flux distribution based at least in part on the first temperature signals and predictive convective and radiative heat losses from the solar receiver, and controls the plurality of heliostats responsively to said computed solar energy flux distribution.

2. The solar energy collection system of claim 1, wherein each of the tubes has a width and the external surface of each of the tubes is imaged by more than one of the plurality of pixels in a direction of the tube width.

3. The solar energy collection system of claim 1, further comprising a temperature sensor configured to detect a temperature of a point on the external surface of the receiver and to generate a second temperature signal indicative thereof, the controller being configured to compute the solar energy flux distribution based at least in part on the second temperature signal.

4. The solar energy collection system of claim 1, further comprising a first temperature sensor configured to measure a temperature of fluid flowing through an inlet of the receiver and to generate a second temperature signal indicative thereof, a second temperature sensor configured to measure a temperature of fluid flowing through an outlet of the receiver and to generate a third temperature signal indicative thereof, wherein the controller is configured to compute the solar energy flux distribution based at least in part on the second and third temperature signals.

5. The solar energy collection system of claim 1, further comprising a flowmeter configured to measure flowrate of fluid through the receiver and to generate a flowrate signal based thereon, wherein the controller is configured to compute the solar energy flux distribution based at least in part on the flowrate signal.

6. The solar energy collection system of claim 1, wherein the weather station transmits instantaneous or predictive weather data to the controller, the controller computing the solar energy flux distribution at least in part on the received weather data.

7. The solar energy collection system of claim 1, wherein the conveyed fluid is transported from the receiver to a thermal power plant after receiving the transmitted thermal energy so as to generate electricity from thermal energy stored in the conveyed fluid.

8. A solar energy collection system comprising:

a solar receiver which receives on an external surface thereof solar radiation reflected from at least one heliostat, the receiver including at least one tube for conveying a fluid therethrough, the external surface transmitting thermal energy from the reflected solar radiation received thereon to the conveyed fluid;

a first thermal imaging device which detects infrared radiation emanating from the external surface of the receiver and measures temperatures of the external surface of the receiver based on the detected infrared radiation; and

a controller which computes solar energy flux distribution on the external surface of the solar receiver based on the measured temperatures from the first thermal imaging device.

9. The solar energy collection system of claim 8, wherein the controller is configured to control aiming of the at least one heliostat responsively to the computed solar energy flux distribution.

10. The solar energy collection system of claim 8, wherein the controller is configured to use time-differential temperature readings of the measured temperatures of the external surface of the receiver to compute solar energy flux distribution.

11. The solar energy collection system of claim 8, further comprising a second thermal imaging device which has a field of view directed at the external surface that does not overlap with a field of view of the first thermal imaging device.

12. The solar energy collection system of claim 8, further comprising a second thermal imaging device which has a field of view directed at the external surface that overlaps with a field of view of the first thermal imaging device.

13. The solar energy collection system of claim 8, wherein the controller is configured to receive instantaneous or predictive weather data from a weather station and to compute the solar energy flux distribution at least in part on the received weather data.

14. The solar energy collection system of claim 8, wherein the receiver external surface includes an external surface of the at least one tube, each tube having a width, the thermal imaging device having a plurality of pixels and being arranged such that the tube external surface is imaged by more than one of the plurality of pixels in the direction of the width.

15. A method for controlling a solar energy collection system, comprising:

detecting infrared radiation emanating from an external surface of a receiver, the receiver including at least one tube for conveying a fluid therethrough;

determining a solar energy flux distribution on the external surface of the receiver based at least in part on the detecting infrared radiation; and

directing the heliostats to reflect incoming solar radiation onto aiming points on the external surface of the receiver based at least in part on the determining a solar energy flux distribution.

16. The method according to claim 15, wherein the detecting, determining and directing are repeated continuously during operation of the solar energy collection system.

17. The method according to claim 15, wherein the detecting infrared radiation includes imaging the external surface of the receiver using a plurality of thermal imaging devices with overlapping fields of view.

18. The method according to claim 15, further comprising detecting temperatures of fluid conveyed into and out of the receiver, the determining being based at least in part on the detecting temperatures of fluid conveyed.

19. The method according to claim 15, further comprising measuring weather data at a location of the solar energy collection system, wherein the determining a solar energy flux distribution is based at least in part on the measuring weather data.

20. The method according to claim 15, wherein the detecting infrared radiation includes imaging the external surface of the receiver using a plurality of thermal imaging devices, and the determining a solar energy flux distribution at any particular time only uses data from ones of the thermal imaging devices that do not look into the sun at that particular time.