WO2013093936A2 - System and method to map heat flux for solar concentrators - Google Patents

System and method to map heat flux for solar concentrators Download PDF

Info

Publication number
WO2013093936A2
WO2013093936A2 PCT/IN2012/000604 IN2012000604W WO2013093936A2 WO 2013093936 A2 WO2013093936 A2 WO 2013093936A2 IN 2012000604 W IN2012000604 W IN 2012000604W WO 2013093936 A2 WO2013093936 A2 WO 2013093936A2
Authority
WO
WIPO (PCT)
Prior art keywords
heat flux
solar concentrator
receiver
mapping
flux
Prior art date
Application number
PCT/IN2012/000604
Other languages
French (fr)
Other versions
WO2013093936A3 (en
Inventor
J.K. Nayak
S.B. Kedare
Prakash MARATH
Pranesh KRISHNAMURTHY
Ranjeet V. BHALERO
Original Assignee
Indian Institute Of Technology Bombay
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Indian Institute Of Technology Bombay filed Critical Indian Institute Of Technology Bombay
Publication of WO2013093936A2 publication Critical patent/WO2013093936A2/en
Publication of WO2013093936A3 publication Critical patent/WO2013093936A3/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
    • G01K7/02—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples
    • G01K7/04—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples the object to be measured not forming one of the thermoelectric materials
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
    • G01K1/02—Means for indicating or recording specially adapted for thermometers
    • G01K1/026—Means for indicating or recording specially adapted for thermometers arrangements for monitoring a plurality of temperatures, e.g. by multiplexing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K17/00—Measuring quantity of heat

Definitions

  • the present invention generally relates to flux mapping system, and more particularly to system and method for mapping heat flux incident on surface of a solar concentrator.
  • the quantity of solar energy actually incident on the surface of the receiver of solar concentrators is expressed in flux.
  • the solar energy is incident on multiple locations on the surface of the receiver of solar concentrator.
  • flux mapping for solar concentrators are based on the principle of thermal imaging. Devices such as infra-red cameras are used for the thermal imaging. This device detects the image produced at the receiver of the concentrator and the brightness of the image is analyzed. The brightness of the image will help to determine the flux intensity.
  • US 20090250052 propose a control mechanism for central receiver systems based on flux present at the receiver.
  • an imaging device is used to detect the digital image formed at the receiver.
  • the brightness of the image is used to decide the control of the central tower and heliostats system.
  • US 20100006087 propose a system and method for measuring flux distribution at the receiver surface of a solar energy collection system.
  • the system uses an infrared thermography detector such as an infrared camera to detect the infrared rays emanating from the surface of the receiver. This can be used for control of focus such as heliostats to achieve uniform flux distribution at the receiver system.
  • the present invention is directed to system and method for mapping the heat flux incident on a surface of the receiver of a solar concentrator.
  • the flux mapping system disclosed analyses temperature profile indicated by high accuracy thermocouples 15 to map the flux.
  • the system uses the temperature profile along a metal strip 12 to determine the heat flux. This method and system can be used for flux mapping of point focus and line focus concentrating solar collectors.
  • the flux mapping system proposed in the present invention is easy to handle, easy to manufacture and has simple calibration techniques.
  • the present invention is robust, cheaper and requires very low maintenance.
  • Figure. 1 illustrates a system for flux measurement in accordance with an aspect of the present invention.
  • Figure 2 illustrates basic system components in accordance with an aspect of the present invention.
  • Figure 3 illustrates a ring with metal strips bent into a shape shown in accordance with an aspect of the present invention.
  • the present invention proposes a system and method for mapping the heat flux incident on a surface of the receiver of a solar concentrator.
  • the flux mapping system disclosed analyses . temperature profile indicated by high accuracy thermocouples 15 to map the flux.
  • the system uses the temperature profile along a metal strip 12 to determine the heat flux.
  • Figure 1 illustrates the system for measuring heat flux on receiver of solar concentrators in accordance with an aspect of present invention.
  • the flux mapping system disclosed comprises of a thin metal wire bent into a ring 10, which will be used for heat flux determination around receivers of circular cross section.
  • the diameter of the ring 10 is 30mm larger than the diameter of the receiver tube to accommodate for other elements of the system.
  • FIG. 2 illustrates the components of the flux measurement system in accordance with an aspect of the present invention.
  • the ring 10 is mounted with small independent and thin metal strips 12 at regular intervals along the circumference. The conduction is neglected based on the use of a thin metal strip 12 having minimum thickness of 2 mm, grooved at required multiple points having sufficient strength.
  • the strip 12 is about 15 mm width and 25 mm length.
  • the width of the metal strip 12 is chosen to provide space for sensor mounting.
  • Flexible thermocouple wires 15 are used as sensors to measure the temperatures on every metal strip 12.
  • the material for the thermocouple sheath is chosen such that it can withstand high temperatures generated due to concentrated flux.
  • the placement of thermocouple wires 15 is strategic; depending on the application and based on expected variation of flux intensity at various points.
  • thermocouple sensors 15 are screwed onto the metal strips 12.
  • High conductivity cement is applied to remove any possible air gap.
  • a special high temperature resistant paint, called Pyropaint is applied to the outer surface of the ring 10. Consequently the emissivity of the metal strips 12 is known for a known paint at different temperatures.
  • the inner side of the ring 10 is covered with 10 mm glass wool insulation 18 to reduce heat loss by convection.
  • the proposed invention measures temperature values on small independent metal strip 12 fixed at the receiver for determining the incident flux.
  • the temperature values are recorded continuously using a data acquisition system.
  • data logging system is used as the data acquisition system to record temperature values.
  • the varying temperature values are recorded to give a variation in the intensity of heat flux.
  • One dimensional heat flow is considered in the system and heat flux is calculated by applying energy balance equations as the heat incident at a point on the metal strip 12 is equal to the heat lost through convection and radiation which can be calculated through known values of temperature on the strip, ambient conditions and emissivity.
  • Figure 3 illustrates the side view of the basic flux mapping system bent as a ring 10 in accordance with an aspect of the present invention.
  • the ring 10 is held around the receiver using a support structure above the receiver which also tracks with the collector. This ensures that the ring 10 always receives the concentrated radiation in the same position.
  • the ring 10 does not form a full circle and has a gap between ends equal to the width of the support block used.
  • a hollow stainless steel block bears the weight of the ring 10 and the thermocouple wires 15.
  • the block is supported on the collector frame with symmetrical supports made of suitable material.

Abstract

The present invention proposes a system and method for mapping the heat flux incident on a surface of the receiver of a solar concentrator. The flux mapping system disclosed analyses temperature profile indicated by high accuracy thermocouples to map the flux. The system uses the temperature profile along a metal strip to determine the heat flux. This method and system can be used for flux mapping of point focus and line focus concentrating solar collectors. The flux mapping system proposed in the present invention is easy to handle, easy to manufacture and has simple calibration techniques. The present invention is robust, cheaper and requires very low maintenance.

Description

Title:
System and method to map heat flux for solar concentrators Field of Invention:
The present invention generally relates to flux mapping system, and more particularly to system and method for mapping heat flux incident on surface of a solar concentrator.
Background:
In an energy based power generation system, the quantity of solar energy actually incident on the surface of the receiver of solar concentrators is expressed in flux. The solar energy is incident on multiple locations on the surface of the receiver of solar concentrator. In recent years, flux mapping for solar concentrators are based on the principle of thermal imaging. Devices such as infra-red cameras are used for the thermal imaging. This device detects the image produced at the receiver of the concentrator and the brightness of the image is analyzed. The brightness of the image will help to determine the flux intensity.
In prior arts, there are two US patents which is in relation to flux mapping system for solar receiver. US 20090250052 propose a control mechanism for central receiver systems based on flux present at the receiver. In this patent, an imaging device is used to detect the digital image formed at the receiver. The brightness of the image is used to decide the control of the central tower and heliostats system. In another patent, US 20100006087 propose a system and method for measuring flux distribution at the receiver surface of a solar energy collection system. The system uses an infrared thermography detector such as an infrared camera to detect the infrared rays emanating from the surface of the receiver. This can be used for control of focus such as heliostats to achieve uniform flux distribution at the receiver system.
But, the problem in these prior arts is that these cameras are more expensive and also the operational cost through post-processing software is very high. It requires skilled person with expertise to handle these cameras. The calibration techniques for such systems and the maintenance of the infrared cameras are complicated. Hence, there is a need for flux mapping system which is easy to use, having simple calibration techniques, cost effective, robust and requires very low maintenance.
Objects of Invention:
1. It is the primary object of the present invention to provide a flux mapping system for solar concentrators.
2. It is another object of the present invention to determine optical flux distribution at the focus or in any other plane.
3. It is another object of present invention to provide flux mapping system which has simple calibration techniques. 4. It is another object of present invention to provide flux mapping system which is of low cost.
5. It is another object of the present invention to provide flux mapping system which is easy to use. 6. It is another object of present invention to provide flux mapping system that is robust.
7. It is another object of present invention to provide flux mapping system which requires very low maintenance.
Summary of Invention:
The present invention is directed to system and method for mapping the heat flux incident on a surface of the receiver of a solar concentrator. The flux mapping system disclosed analyses temperature profile indicated by high accuracy thermocouples 15 to map the flux. The system uses the temperature profile along a metal strip 12 to determine the heat flux. This method and system can be used for flux mapping of point focus and line focus concentrating solar collectors.
The flux mapping system proposed in the present invention is easy to handle, easy to manufacture and has simple calibration techniques. The present invention is robust, cheaper and requires very low maintenance. Brief description of drawings:
Figure. 1 illustrates a system for flux measurement in accordance with an aspect of the present invention. Figure 2 illustrates basic system components in accordance with an aspect of the present invention.
Figure 3 illustrates a ring with metal strips bent into a shape shown in accordance with an aspect of the present invention.
Detailed description of the Invention:
1 The present invention proposes a system and method for mapping the heat flux incident on a surface of the receiver of a solar concentrator. The flux mapping system disclosed analyses . temperature profile indicated by high accuracy thermocouples 15 to map the flux. The system uses the temperature profile along a metal strip 12 to determine the heat flux.
The proposed system and the method for measuring heat flux on receiver of solar concentrators are explained in reference with the accompanying drawings according with an aspect of present invention.
Figure 1 illustrates the system for measuring heat flux on receiver of solar concentrators in accordance with an aspect of present invention. The flux mapping system disclosed comprises of a thin metal wire bent into a ring 10, which will be used for heat flux determination around receivers of circular cross section. The diameter of the ring 10 is 30mm larger than the diameter of the receiver tube to accommodate for other elements of the system.
Figure 2 illustrates the components of the flux measurement system in accordance with an aspect of the present invention. The ring 10 is mounted with small independent and thin metal strips 12 at regular intervals along the circumference. The conduction is neglected based on the use of a thin metal strip 12 having minimum thickness of 2 mm, grooved at required multiple points having sufficient strength. In the current system, the strip 12 is about 15 mm width and 25 mm length. The width of the metal strip 12 is chosen to provide space for sensor mounting. Flexible thermocouple wires 15 are used as sensors to measure the temperatures on every metal strip 12. The material for the thermocouple sheath is chosen such that it can withstand high temperatures generated due to concentrated flux. The placement of thermocouple wires 15 is strategic; depending on the application and based on expected variation of flux intensity at various points. The thermocouple sensors 15 are screwed onto the metal strips 12. High conductivity cement is applied to remove any possible air gap. A special high temperature resistant paint, called Pyropaint is applied to the outer surface of the ring 10. Consequently the emissivity of the metal strips 12 is known for a known paint at different temperatures. The inner side of the ring 10 is covered with 10 mm glass wool insulation 18 to reduce heat loss by convection.
The proposed invention measures temperature values on small independent metal strip 12 fixed at the receiver for determining the incident flux. The temperature values are recorded continuously using a data acquisition system. Preferably, data logging system is used as the data acquisition system to record temperature values. The varying temperature values are recorded to give a variation in the intensity of heat flux. One dimensional heat flow is considered in the system and heat flux is calculated by applying energy balance equations as the heat incident at a point on the metal strip 12 is equal to the heat lost through convection and radiation which can be calculated through known values of temperature on the strip, ambient conditions and emissivity.
Figure 3 illustrates the side view of the basic flux mapping system bent as a ring 10 in accordance with an aspect of the present invention. The ring 10 is held around the receiver using a support structure above the receiver which also tracks with the collector. This ensures that the ring 10 always receives the concentrated radiation in the same position. The ring 10 does not form a full circle and has a gap between ends equal to the width of the support block used. A hollow stainless steel block bears the weight of the ring 10 and the thermocouple wires 15. The block is supported on the collector frame with symmetrical supports made of suitable material.

Claims

We Claim:
A system for mapping heat flux for a solar concentrator receiver, comprising: a. a thin metal wire bent into a ring 10;
b. a series of small independent and thin metal strips 12 mounted along circumference of said ring 10;
c. a series of thermocouple wires 15 connected with said metal strip 12 along surface of said metal strip 12;
d. an insulation layer 18;
e. a data acquisition system.
The system for mapping heat flux for a solar concentrator receiver as claimed in claim 1 , wherein diameter of said ring 10 is 30mm larger than diameter of said receiver.
The system for mapping heat flux for a solar concentrator receiver as claimed in claim 2, wherein high temperature resistance paint is applied to outer surface of said ring.
The system for mapping heat flux for a solar concentrator receiver as claimed in claim 1, wherein said thin metal strips 12 has thickness of at least 2mm.
The system for mapping heat flux for a solar concentrator receiver as claimed in claim 4, wherein said thin metal strips 12 has width of 15mm and length of 25mm.
The system for mapping heat flux for a solar concentrator receiver as claimed in claim 5, wherein high conductivity cement is applied to said thin metal strip.
7. . The system for mapping heat flux for a solar concentrator receiver as claimed in claim 6, wherein said thin metal strips 12 is grooved at multiple points to accommodate said thermocouple wires 15.
8. The system for mapping heat flux for a solar concentrator receiver as claimed in claim 7, wherein said thermocouple 15 is fixed with said metal strip 12.
The system for mapping heat flux for a solar concentrator receiver as claimed in claim 1, wherein said insulation layer 18 having thickness of at least 10mm is provided at inner side of said ring 10.
10. The system for mapping heat flux for a solar concentrator receiver as claimed in claim 1 , wherein said data acquisition system is used to record temperature values continuously.
11. The system for mapping heat flux for a solar concentrator receiver as claimed in claim 10, wherein said data acquisition system is a data logging system.
12. > A method of mapping heat flux for a solar concentrator receiver, comprising: a. said ring 10 held around said receiver;
b. measuring temperature values along said metal strip 12 using said thermocouple wires 15;
c. continuously recording said temperature values using said data acquisition system; and
d. calculating said heat flux using said temperature values.
13. The method of mapping heat flux for a solar concentrator receiver as claimed in claim 12, wherein said ring 10 receives concentrated radiation in same position. 14. The method of mapping heat flux for a solar concentrator receiver as claimed in claim 12, wherein said temperature values is continuously measured at discrete points of said receiver.
15. The method of mapping heat flux for a solar concentrator receiver as claimed in claim 12, wherein varying said temperature values are recorded to provide variation in intensity of said heat flux.
16. The method of mapping heat flux for a solar concentrator receiver as claimed in claim 12, wherein said heat flux is calculated by applying energy balance equations using said temperature values.
PCT/IN2012/000604 2011-09-12 2012-09-10 System and method to map heat flux for solar concentrators WO2013093936A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IN2552MU2011 2011-09-12
IN2552/MUM/2011 2011-09-12

Publications (2)

Publication Number Publication Date
WO2013093936A2 true WO2013093936A2 (en) 2013-06-27
WO2013093936A3 WO2013093936A3 (en) 2013-10-10

Family

ID=48669652

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IN2012/000604 WO2013093936A2 (en) 2011-09-12 2012-09-10 System and method to map heat flux for solar concentrators

Country Status (1)

Country Link
WO (1) WO2013093936A2 (en)

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0004220B1 (en) * 1978-03-07 1981-10-14 Compagnie Des Lampes Solar energy collector
US4318394A (en) * 1980-01-11 1982-03-09 Alexander William C Solar energy concentrator
US5245986A (en) * 1991-01-14 1993-09-21 Yeda Research And Development Company Limited Solar receiver
US5995889A (en) * 1997-11-26 1999-11-30 Nissan Research & Development, Inc. Automatic temperature control method and apparatus for an automotive vehicle
US20020135980A1 (en) * 2000-07-11 2002-09-26 The Ohio State University High heat flux electronic cooling apparatus, devices and systems incorporating same
WO2004023048A1 (en) * 2002-09-06 2004-03-18 Kraftanlagen Munchen Gmbh Combined and simplified ceramic or metallic volumetric absorber modules
US20040249860A1 (en) * 2003-03-26 2004-12-09 Stechschulte Theodore J. Apparatus for collecting, storing and transmitting fishing information
US20050126560A1 (en) * 2003-12-10 2005-06-16 The Boeing Company Solar collector and method
US20060187074A1 (en) * 2003-01-31 2006-08-24 Fmc Tech Limited Monitoring device for a medium voltage overhead line
US20090250052A1 (en) * 2007-11-12 2009-10-08 Luz Ii Ltd. Solar receiver with energy flux measurement and control
US20100319679A1 (en) * 2009-06-18 2010-12-23 Hon Hai Precision Industry Co., Ltd. Heat-distribution sensor and solar tracker having same

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0004220B1 (en) * 1978-03-07 1981-10-14 Compagnie Des Lampes Solar energy collector
US4318394A (en) * 1980-01-11 1982-03-09 Alexander William C Solar energy concentrator
US5245986A (en) * 1991-01-14 1993-09-21 Yeda Research And Development Company Limited Solar receiver
US5995889A (en) * 1997-11-26 1999-11-30 Nissan Research & Development, Inc. Automatic temperature control method and apparatus for an automotive vehicle
US20020135980A1 (en) * 2000-07-11 2002-09-26 The Ohio State University High heat flux electronic cooling apparatus, devices and systems incorporating same
WO2004023048A1 (en) * 2002-09-06 2004-03-18 Kraftanlagen Munchen Gmbh Combined and simplified ceramic or metallic volumetric absorber modules
US20060187074A1 (en) * 2003-01-31 2006-08-24 Fmc Tech Limited Monitoring device for a medium voltage overhead line
US20040249860A1 (en) * 2003-03-26 2004-12-09 Stechschulte Theodore J. Apparatus for collecting, storing and transmitting fishing information
US20050126560A1 (en) * 2003-12-10 2005-06-16 The Boeing Company Solar collector and method
US20090250052A1 (en) * 2007-11-12 2009-10-08 Luz Ii Ltd. Solar receiver with energy flux measurement and control
US20100319679A1 (en) * 2009-06-18 2010-12-23 Hon Hai Precision Industry Co., Ltd. Heat-distribution sensor and solar tracker having same

Also Published As

Publication number Publication date
WO2013093936A3 (en) 2013-10-10

Similar Documents

Publication Publication Date Title
Ballestrín et al. Hybrid heat flux measurement system for solar central receiver evaluation
CN103063328B (en) Method and device for non-contact measurement of interior temperature of open-air coal stack
CN101887039B (en) Vacuum measuring device for measuring performance of solar collector tube
CN102207512B (en) Wind vane anemometer and wind direction and velocity device
CN101432608A (en) Apparatus and method for measuring the temperature on an induction heating apparatus
US9322576B2 (en) Receiver module for solar power station with in-built thermal monitoring
WO2011128927A3 (en) Measuring thermal parameters of a building envelope
EP2591325A1 (en) Infrared temperature measurement and stabilization thereof
CN113063341B (en) Device and method for three-dimensional real-time measurement of thickness of annular flow liquid film and interfacial wave
Pfänder et al. Infrared temperature measurements on solar trough absorber tubes
CN205080081U (en) Measurement device for biggest heat transfer power of solar energy gravity heat pipe
WO2013093936A2 (en) System and method to map heat flux for solar concentrators
Zheng et al. Experimental test of a novel multi-surface trough solar concentrator for air heating
CN105157847A (en) Online accurate temperature measurement method and online accurate temperature measurement system for electric power equipment
Ballestrín et al. Heat flux and temperature measurement technologies for concentrating solar power (CSP)
JP2007248201A (en) Radiation thermometer
CN110342130A (en) A kind of system of the array distributed monitoring fused salt storage tank leakage of thinning FBG
Mokhtar et al. A model for improved solar irradiation measurement at low flux
Sartarelli et al. Heat flux solarimeter
CN104489889B (en) A kind of cut-tobacco drier barrel temperature on-line detection device and method
Tsilingiris The glazing temperature measurement in solar stills–errors and implications on performance evaluation
JP5937039B2 (en) Pyranometer
CN205483274U (en) Power plant boiler multiple spot wireless temperature collection system
JPS61296229A (en) Thermocouple and method for mounting the same
CN102944333B (en) Testing device and testing method for heat loss of slot-type solar energy heat collecting tube

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12860831

Country of ref document: EP

Kind code of ref document: A2

122 Ep: pct application non-entry in european phase

Ref document number: 12860831

Country of ref document: EP

Kind code of ref document: A2