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Informes Técnicos Ciemat 961Abril,2001
Direct Heat-Flux MeasurementSystem (MDF)for Solar CentralReceiver Evaluation
J. Ballestrín
Plataforma Solar de Almería
Toda correspondenica en relación con este trabajo debe dirigirse al Servicio de
Información y Documentación, Centro de Investigaciones Energéticas, Medioambientales y
Tecnológicas, Ciudad Universitaria, 28040-MADRID, ESPAÑA.
Las solicitudes de ejemplares deben dirigirse a este mismo Servicio.
Los descriptores se han seleccionado del Thesauro del DOE para describir las materias
que contiene este informe con vistas a su recuperación. La catalogación se ha hecho
utilizando el documento DOE/T1C-4602 (Rev. 1) Descriptive Cataloguing On-Line, y la
clasificación de acuerdo con el documento DOE/TIC.4584-R7 Subject Categories and Scope
publicados por el Office of Scientific and Technical Information del Departamento de Energía
de los Estdos Unidos.
Se autoriza la reproducción de los resúmenes analíticos que aparecen en esta
publicación.
Depósito Legal: M-14226-1995ISSN: 1135-9420ÑIPO: 402-01-008-3
Editorial CIEMAT
CLASIFICACIÓN DOE Y DESCRIPTORES
S14
HEAT FLUX; MEASURING METHODS; SOLAR THERMAL CONVERSIÓN; SOLAR
THERMAL POWER PLANTS; SOLAR RECEIVERS; SOLAR FLUX
Direct Heat-Flux Measurement System (MDF)for Solar Central Receiver Evaluation
Ballestrín, J.44 pp. 18 fig. 18refs.
Abstract:
A direct flux measurement system, MDF, has been designed, constructed and mounted on top of the SSPS-CRS tower at the Plataforma Solar de Almería (PSA) in addition to an indirect flux measurement systembased on a CCD camera. It's one of the main future objectives to compare systematically both measurementsof the concentrated solar power, increasing in this way the confidence in the estímate of this quantity. Todayeverything is prepared to perforan the direct flux measurement on the apernare of solar receivers: calorimeterarray, data acquisition system and software. The geometry of the receiver determines the operation andanalysis procedures to obtain the incident power onto the defined área.
The study of previous experienees with direct flux measurement systems has been useful to define a new,simpler and more aecurate system. A description of each component of the MDF system is included,focusing on the heat-flux sensors or calorimeters, which enables these measurements to be done in a fewseconds without water-cooling.
The incident solar power and the spatial flux distribution on the aperture of the volumetric receiver Hitrec IIare supplied by the above-mentioned MDF system. The first results obtained during the evaluation of thissolar receiver are presented including a sunrise-sunset test. AU these measurements have been concentratedin one coeffícient that describes the global behavior of the Solar Power Plant.
Sistema de Medida Directa de Flujo de Calor (MDF)para Evaluación de Receptores Solares Centrales
Ballestrín, J.44 pp. 18 fig. 18refs.
Resumen:
Un sistema de medida directa de flujo, MDF, ha sido diseñado, construido y montado en la parte alta de latorre SSPS-CRS en la Plataforma Solar de Almería (PSA) junto a un sistema de medida indirecta de flujobasado en una cámara CCD. Uno de los futuros objetivos es llegar a comparar sistemáticamente las medi-das que de la potencia solar concentrada hagan los dos sistemas, aumentando de este modo la confianza enla estimación de esta magnitud. Actualmente todo está a punto para llevar a cabo la medida directa de flujoen la apertura de receptores solares: grupo de calorímetros, sistema de adquisición de datos y software. Lageometría del receptor determina los procedimientos de operación y análisis para obtener la potencia inci-dente sobre el área definida.
El estudio de experiencias previas con sistemas de medida directa de flujo ha sido de gran ayuda para definirun nuevo sistema más sencillo y exacto. La descripción de cada componente del sistema MDF es presen-tada, haciendo énfasis en los calorímetros, los cuales permiten que estas medidas sean llevadas a cabo enunos pocos segundos evitando la refrigeración con agua.
La potencia solar incidente y la distribución espacial de flujo en la apertura del receptor volumétrico HitrecII son obtenidas por el sistema MDF. Los primeros resultados obtenidos durante la evaluación de estereceptor solar son presentados, incluyendo un test de orto a ocaso. Todas estas medidas han sido concentra-das en un coeficiente que describe el comportamiento global de la Planta Solar.
ACKNOWLEDGMENTS:
This work is included in the evaluation of the HITREC II volumetric receiver, which is taking
place during this year at the Platafonna Solar de Almería (PSA). Thanks to the responsible of
the Solar Central Receiver Technology project, M. Romero, who encouraged these ideas from
the beginning. Thanks to the responsible of the Instrumentation Department, G. García, for
the technical support. Special mention to my colleagues: R. Monterreal, A. Valverde, J.
Fernández, I. Borretzen, R. Maillard and J. A. García. I'd like to thank everybody who helped
this research with his participation or advice. Thanks to all the kind people of Operation and
Maintenance.
Direct heat-flux measurement system (MDF) for solar receiver evaluation
CONTENTS:
1 INTRODUCTION 1
2 HITREC II RECEIVER 2
3 FLUX MEASUREMENT 4
4 THE MDF SYSTEM (MEDIDA DIRECTA DE FLUJO) 5
4.1 HEAT FLUX MICROSENSOR (HFM) 6
4.2 DATA ACQUISITION SYSTEM 8
4.3 OPERATION PROCEDURE AND ALGORITHMS FOR THE ANALYSIS 10
5 RESULTS 18
6 SUMMARY 23
7 RELATED LITERATURE 23
BOOKS 23REPORTS 24
APPENDIX 1: CALIBRATION SHEETS 25
J. Ballestrin
Direct heat-flux measurement system (MDF) for solar receiver evaluation
FIGURES:
FIGURE 1: LATERAL VIEW OF THE RECEIVER 2
FIGURE 2: HITREC I RECEIVER APERTURE 3
FIGURE 3: HITREC II RECEIVER APERTURE 4
FIGURE 4: HEAT FLUX MICROSENSOR (HFM) 7
FIGURE 5: HEAT FLUX MICROSENSOR 8
FIGURE 6: MDF DIAGRAM 9
FIGURE 7: DASYLAB WORKSHEET 9
FIGURE 8: LAYOUT OF THE HFM CALORIMETERS IN THE BAR 10
FIGURE 9: MDF AND CCD BAR 11
FIGURE 10: SIGNAL OF THE REFERENCE CALORIMETER 12
FIGURE 11: GEOMETRY BAR-RECEIVER APERTURE 12
FIGURE 12: BAR-RECEIVER APERTURE 13
FIGURE 13: RECEIVER APERTURE RECORDS 14
FIGURE 14: SPATIAL FLUX DISTRIBUTION IN THE RECEIVER APERTURE 15
FIGURE 15: FLUX DISTRIBUTION 2D 17
FIGURE 16: FLUX DISTRIBUTION 3D 18
FIGURE 17: SUNRISE-SUNSETOF 13-2-2001 21
FIGURE 18: MDF EXCEL TOOL 22
J. Ballestrín
Direct heat-flux measurement system (MDF) for solar receiver evaluation
1 INTRODUCTION
A direct flux measurement system, MDF, has been designed, constructed and mounted on top
of the SSPS-CRS tower at the Plataforma Solar de Almería (PSA) in addition to an indirect
flux measurement system based on a CCD camera. It's one of the main future objectives to
compare systematically both measurements of the concentrated solar power, increasing in this
way the confidence in the estímate of this quantity. Today everything is prepared to perform
the direct flux measurement on the aperture of solar receivers: calorimeter array, data
acquisition system and software. The geometry of the receiver determines the operation and
analysis procedures to obtain the incident power onto the defined área.
The study of previous experiences with direct flux measurement systems has been useful to
define a new, simpler and more accurate system. The Germán HFD (Heat Flux Distribution)
system was mounted in 1981 at the top of the SSPS-CRS tower to evalúate solar receivers.
The mstrumentation consists of ten calorimeters "Hycal Engineering" which were mounted in
the traversing bar. This bar could be hidden behind a protecting píate if no measurements
were taken and it was moved in horizontal direction in front of the receiver aperture when
measurements were taken. The calorimeters were designed to receive heat on 16-mm
diameter front face. This face and the cooled heat sink were connected to copper-constantan
thermocouples. The thermal voltages and the differences were proportional to the incoming
heat flux. The temperature could go up to slightly more than 200°C without changing the
calibration curve. Because the response time of this sensor is around 0.5 seconds, it was
necessary to spend 80 seconds to drive the total measurement sequence and the driving time
for the return-run carne to 70 seconds. For this reason, the bar was water-cooled with
incoming flow of 14 bars and the calorimeters too with a sepárate cooling system at a pressure
level of 7 bars. This complicated cooling procedure and the big áreas scanned were the main
negative points of this system.
The Spanish MFV (Medida de Flujo receptores Volumétricos) system was mounted in 1988
at the top of the SSPS-CRS tower to evalúate volumetric receivers. This system was
composed of the following elements:
• A measuring cross with 13 calorimeters "HYCAL Engineering" used to make
the measurements. These calorimeters cooled with water at a constant flow of
1.4 liters per minute allow ±3% accuracy, ±0.5% repetitivity and
±3%linearity.
• Positioning device to place the cross in the measurement positions pivoting in
a fíx point and stand by. This device includes a motor, reduce and switch
limits.
J. Ballestrín 1
Direct heat-flux measurement system (MDF) for solar receiver evaluation
® Control boards to centralize all the digital signáis of the system and
responsible for any movements of the cross.
« Acquisition cards to receive analog and digital signáis and transfer them
through the net Une of the computer.
The cross was moved by the positioning device and remained in front of the receiver aperture
for fíve seconds. During this time, it performed the necessary measurements after which it
was retrieved immediately to allow it to be cooled. This system represented a forward step
because the resolution in the flux measurements increased and the operation procedure for the
moving bar was simpler.
A description of each component of the new MDF system is included, focusing on the heat-
flux sensors or calorimeters, which enables these measurements to be done in a few seconds
without water-cooling.
The incident solar power and the spatial flux distribution on the aperture of the volumetric
receiver Hitrec II are supplied by the above-mentioned MDF system. The fírst results
obtained during the evaluation of this solar receiver are presented including a sunrise-sunset
test. All these measurements have been concentrated in one coeffícient that describes the
global behavior of the Solar Power Plant.
The volumetric receiver under evaluation is the Hitrec II, which has been installed at the 43
meters level of the CRS tower at the PSA.
Figure 1: Lateral view of the receiver
J. Bailestrín
Direct heat-flux measurement system (MDF) for solar receiver evaluation
T h e Hitrec I receiver was evaluated at the P S A in 1997/98 achieving 200 k W ; during these
tests, problems on the thermal stractural stability of the supporting steel membrane were
observed. This is one of the reasons for the design o f the n e w Hitrec II. However , the circular
apernare o f 880 ± 1 m m of diameter and the hexagonal absorber cups o f the Hitrec I receiver
are going to b e the same.
•¿Sai
Figure 2: Hitrec I receiver aperture
Several results obtained in the past test campaign of the Hitrec I receiver were:
« Efficiency 68% at 980 °C
« Flux Average 400-500 kW/m2
• Flux Peak 600 kW/m2
• Incoming power on the receiver aperture 200 kW
J. Ballestón
Direct heat-flux measurement system (MDF) for solar receiver evaluation
. - y *•-•
y
Figure 3: Hitrec II receiver aperture
In this context, from the point of view of the flux measurement the effective área of the
receiver to be considered is the área covered by hexagonal cups including the gaps between
them. Therefore, the data acquisition is defíned to obtain the flux distribution and the incident
power in this área.
Flux measurement is essential to obtain the efficiency of the receiver, T|R, because the flux
distribution on the receiver aperture supplies the radiant power P¡ incident on the receiver
aperture. The receiver efficiency is:
IR =Pi
(1)
Where Po is the outgoing power through the coolant that is represented by the expression:
(2)Po = m cp AT
where:
© m is the coolant mass flow rate.
9 cp specific heat capacity.
J. Ballestrín
Direct heat-flux measurement system (MDF) for solar receiver evaluation
» AT temperature difference between the incoming temperature and the
outgoing temperature of the coolant.
The measurement of the radiant power, which is refiected by the heliostat field, presents more
diffículties. There are two methods for the measurement of this quantity:
> The first one is a direct method based on a moving bar with a calorimeter array passing in
a parallel fíat in front of the receiver aperture. The signáis from these calorimeters supply
the flux distribution on the receiver and the integration of this map over the interesting
área provides the incoming power on the receiver aperture. The main disadvantages of
this method are:
o Data are obtained only in specifíc positions of the total área.
• Less accuracy during transients.
© The longer recording data time the less accurate measurement.
However, the main advantages of this method are the simplicity and the fact that it is a direct
method.
> The second method is indirect. A lambertian píate passes in front of the receiver aperture
isotropically reflecting the concentrated radiation. A CCD camera records a set of images
from a moving píate. Using a calorimeter located in the surroundings of the receiver
aperture does the calibration of the CCD camera. The processing of the recorded images
allows the flux distribution on the receiver and the integration of this map over the
interesting área provides the incident power onto the receiver aperture. This method
presents several advantages compared with the direct philosophy:
• A better spatial resolution.
® A smaller data acquisition time.
It's one of the main objectives in the future to compare systematically both measurements
increasing the confidence in the estímate of the incident power and the flux distribution on the
aperture of the volumetric receiver.
4 THE MDF SYSTEM (MEDIDA DIRECTA DE FLUJO)
The next system improves the technical deficiencies of the previous direct flux measurement
systems. A new kind of calorimeters with response times of microseconds allows thinking in
an instantaneous direct flux measurement. Based in this principie a moving bar with several
of these sensors has been built. The moving bar passes in front of the receiver aperture in a
parallel plañe pivoting in a fix point placed under the receiver aperture, in the vertical line of
J. Ballestón 5
Direct heat-flux measurement system (MDF) for solar receiver evaluation
the center. Using a fast acquisition system for these calorimeters and a convenient moving bar
speed allow measuring instantaneously the flux distribution without cooling.
The bar with calorimeters and the lambertian plates used in the indirect method with CCD
camera are mounted together. Working in the same plañe with both methods is a good chance
to compare the results.
In 1997, the United States Navy successfully measured the heat flux pro file across a solid
rocket motor exhaust plume. One of these sensors was swept through the exhaust plume of the
solid rocket motor immediately downstream of the nozzle exit plañe. The results of these tests
represented a signifícant milestone in flux measurement history due to the extreme conditions
of the tests. During this year The National Aerospace Laboratories in Kakuda (Japan) has
used a similar system with an array of these calorimeters to investígate the rocket engines. An
aerospike nozzle rocket engine has a curved jet attachment surface in the hot gas stream
produced by a linear array of cell combustors. This arrangement produces a controlled
expansión of the hot gases that can be optimized for a range of altitudes. The attachment
surface of the aerospike nozzle is subjected to a high heat load, however. An array of these
sensors was employed to measure the distribution of this heat load.
These previous experiences in the aerospace field allow thinking in a successful direct flux
measurement system in the solar thermal field.
4.1 Heat Flux Microsensor (HFM)
Vatell's Heat Flux Microsensors are made using thin film processes. Thin film construction
gives the sensors many unique advantages:
o The Industry's fastest response: 2-6 microseconds
• Minimal effects on measured variables.
• Operates in temperatures up to 850°C (300°C in our case) without
external cooling.
• Measures both heat flux and temperature at the face of the sensor.
• Measures heat flux in all three modes.
o Low electrical noise.
• Sensitivity: 15 ^V/kW/m2
© Front face of 6.32 mm diameter.
© Accuracy: ± 3%
J. Ballestrín
Direct heat-flux measurement system (MDF) for solar receiver evaluation
Figure 4: Heat Flux Microsensor (HFM)
Two measurements are made with the HFM:
> The first is a temperature measurement obtained from a resistance temperature
sensing element (Resistance Temperature Sensor, RTS) which consists of a puré
platinum thin film deposited in a loop pattern around the outer edge of the sensor face.
> The second is a heat flux measurement obtained from a thermopile heat flux
sensor (HFS) that occupies most of the surface.
The RTS measurement is critical to proper heat flux measurement, because the HFS is
temperature dependent. The RTS relies on the fact that the film resistance changes as a
function of temperature. This function is cióse to linear for most temperature of interest,
although strictly speaking it is better described by a cubic polynomial:
T = aRi +b R2 +cR + d (3)where:
• T is the temperarme (in °C).
• a, b, c, d are the coefficients of the polynomial, which are given on the
calibration data sheet supplied with each sensor by Vatell (Appendix 1).
• R is the eléctrica! resistance of the RTS (in ohms).
The resistance of the RTS is related to the voltage by:
R = ̂ - + Ro (4)
where:
J. Ballestrin
Direct heat-flux measurement system (MDF) for solar receiver evaluation
0 VRTS is the voltage output of the RTS amplifier channel (in volts), which may
be positive or negative.
is the excitation current (in amperes) through the RTS used to genérate
S, equal to 0.001 amperes in our case.
HFM
RTS Temperature
HFS Flux
Figure 5: Heat Flux Microsensor
Once the temperature, T, is known, the heat flux can be computed by:
v,HFS
Signal 1
Signal 2
(5)gT + h
where:
© q" is the heat flux in W/cm2.
• VHFS is the instantaneous voltage signal in uV from the HFS.
• g, h are the coefficients for the relationship between sensitivity and
temperature, which are given on the calibration data sheet supplied with each sensor by Vatell
(Appendix 1).
4.2 Data Acquisition System
The MDF system is mainly a data acquisition system with three main components (Figure 6):
• Moving bar with eight HFM calorimeters.
• Acquisition card with 32 differential channels of 3 ¡aV of highest
resolution which represents a flux resolution of 0.2 kW/m2 and a power
resolutionof 0.006 W.
© Software for the data acquisition (Dasylab) and for the analysis (Matlab).
The signáis from the calorimeters are acquired by the acquisition card of the 6031E family,
which is integrated in a PXI/CPCI (National Instruments) placed in a rack at the top of the
J. Ballestrín
Direct heat-flux measurement system (MDF) for solar receiver evaluation
CRS tower. The transmission of the data to the PC in the operation room is performed by
optical fíber, which is a guarantee of the good quality of the recorded data.
Movina bar + 8 calorimeters
Acquisition card
Optical fiber
PC + Software
Figure 6: MDF diagram
The easy to use Dasylab software helps to solve complex data acquisition scenarios easily and
quickly by working with a flowchart directly on the screen (Figure 7). Module icons are
placed on the screen and connected with wires in a schematic diagram, which represents the
fiow of data through the system.
File £dit Modylss Ejípenment J¿isw J3ptíons X^indow
^í'H'l'al D|GS|B1 % N | i l AI Nal ¿\ -M-M 1-AJD
*Í5í
ISWBfA/D
-fl-12'
-rs-re-i?*
I—-n- F 2
LLJ.IT 3:53:54"^
; i Dibujo ~ fe Qj Autoformas ^
l'fég. 16 Sec. 4 " 18/26 1'A~ ~ !.¡n._ _ Col. ¡'SP.B ÍBCA' |S;T ¡IJOJÍ J Español (ES;^a'stait||-:| ^ c g g g ^ »|;j :^JExplorando ...I BjCopy of inlo,..|lg|,PASYLab...: EgMATLAB C... [ 3:59
Figure 7: Dasylab worksheet
J. Ballestrín
Direct heat-flux measurement system (MDF) for solar receivers evaluation
Dasylab allows fast sampling rates under Windows. Given the proper hardware, data can be
acquired at rates of more than 800 kHz and can continuously be displayed on Une at more
than 100 kHz.
4.3 Operation procedure and algorüthms for the analysis
The new system improves the technical deñciencies of the previous direct flux measurement
systems. A new kind of calorimeters with response times of microseconds allows an almost
instantaneous direct flux measurement. Based on this principie a moving bar with eight of
these sensors has been built with a sheet of carbón steel:
® After this campaign of tests, it has been proved that aluminum would have been a
better choice because the máximum temperature achieved in the bar was 200 °C and it
would have been lighter.
• The two extremes calorimeters were positioned nearer to the edge to avoid the
problem of extrapolation.
• During the ñrst tests with the moving bar the fifth calorimeter (522-mm) was
damaged. The lack of confídence in this sensor forced the analyst to make the
decisión to reject this information.
The eight HFM calorimeters are placed in the bar in order to obtain an optimal resolution of
the área of interest (Figure 8).
40 mn15 mm
1045 mm
6..32 mm
872 mm
722 mm
622 mm
522 mm472 mm422 mm
322 mm
172 mm
0 mm
Figure 8: Layout of the HFM calorimeters in the bar
J. Ballestrín 10
Direct heat-flux measurement system (MDF) for solar receiver evaluation
The moving bar passes in front of the receiver aperture at a distance of 25 cm in a parallel
plañe pivoting in a fix point, P (0, -D), placed under the receiver aperture, in the vertical line
of the center O (0,0). Using an acquisition rate of 40 data/s for these calorimeters and a
moving bar speed of approximately 0.21 rad/s allow the flux distribution to be measured
almost instantaneously without cooling. Of course, this is not a fix recipe and could be
different depending on many factors.
The bar with calorimeters and the lambertian plates used in the indirect method with CCD
camera are mounted together. Working in the same plañe with both methods is a good chance
to compare the results.
1030 mm
MDF o
©
o535 mm
CCD
Figure 9: MDF and CCD bar
The moving bar pivots in a fix point placed under the receiver aperture, in the vertical line of
the receiver aperture center. Two small sticks made of carbón steel ("hot fingers") are the
references to estimate the needed time by the moving bar to sean the receiver aperture
(Figures 10,11,12). These sticks cover one of the fast calorimeters in two positions of the
receiver aperture. In this way, the angular speed of the moving bar in the interesting área is
obtained. In the next figure, it is presented the recorded signal from the reference calorimeter
during the movement of the bar from the parking position to the receiver aperture and return.
J. Ballestrín 11
Direct heat-flux measurement system (MDF) for solar receiver evaluation
700
Figure 10: Signal of the reference calorimeter
Hot fíngers
Aperture
MDF
Reference calorimeter
Figure 11: Geometry bar-receiver aperture
J. Ballestrín 12
Direct heat-flux measurement system (MDF) for solar receiver evaluation
The bar with calorimeters and the lambertian plates used in the indirect method with CCD
camera are mounted together. Working in the same flat with both methods is a good chance to
compare the results. On the other hand, the calorimeter bar is placed at a z distance from the
rotational axis (Figure 9); this fact has been considered in the data analysis.
Figure 12: Bar-receiver aperture
When the moving bar and the eight calorimeters pass in front of the receiver aperture a set of
N flux measurements, F¡j, are obtained in the positions \Xy,yy). These positional variables
are the Cartesians coordinates referred to the center 0(0,0) of the receiver aperture:
(6)
where:
« Lj represents the distance of each calorimeter from the pivoting point.
© D is the distance between the center of the receiver aperture and the pivoting
point.
J. Ballestrín 13
Direct heat-flux measurement system (MDF) for solar receiver evaluation
A matrix M(N, 15) is obtained:
® The first column represents the time.
« Two columns per each HFM calorimeter; the row i represent the same
angle and the column j the same sensor.
Two relevant angles have to be considered to estímate the angle supported by the two hot
fingers and the axis bar:
. .R + z.a - -are sm( )
P = are sin( - )
where R is radio of the circular aperture.
5.5 6.0 6.5 7.0
Time ( s )
(7)
E
IXDU_
i uu -
600-
500-
400-
300-
200-
100-
Hot finger t•
1 "o1 nI Q
" o0" T * '
1 1
Eg * T- • -T7
.i"
1
(O5*? "na
-4" - i *
1 1 '
o . v
o » ... Vo ". ^
0 ^ 0 " 7
3 °O *4¿4-; ° ' 7
" a "1 • ""* 0 ^
Bm "' ° Q V
a ^g
Q *
n B
a
fHot finger
7.5 8.0
Figure 13: Receiver aperture records
When the MDF bar pass behind the two hot fingers the reference calorimeter is covered
twice, the times TI and T2 are estimated and the time needed to sean the receiver aperture
with the MDF bar is obtained by:
The angular speed of the bar is:(8)
co =AT
(9)
J. Ballestrín 14
Direct heat-flux measurement system (MDF) for solar receiver evaluation
So, the angles 8¡ for the times t¡ can be obtained by:
(10)
The radiant power incident on the aperture is obtained by integrating the flux distribution over
the aperture área. Previously it was needed to obtain the flux distribution with a higher
resolution in the different bar directions. So it is possible to interpólate in every temporal
array of data, t¡, with a minimal error due to the flux distribution has a soft shape. After
interpolating with a gap of 10 mm a set of m data is obtamed. It could be possible to
interpólate with a smaller gap but there is not any significant change in the incident power
obtained in the posterior integration and, on the contrary, the calculation time increases.
To obtain only the n (n~3000) data in the interesting área, n<m, a set of conditions are
applied.
Receiver aperture
-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4
Figure 14: Spatial flux distribution on the receiver aperture
To obtain the incident power onto the receiver aperture the integration of the flux distribution
over the interesting área, A, is done by:
(11)
where F¡ is each of the flux data in the área.
J. Ballestrín 15
Direct heat-flux measurement system (MDF) for solar receiver evaluation
To obtain the error of the incident power, three main errors have to be considered:
® The integration error from the equation 11, AP i.
® The interpolaron error, AP2.
® And the error due to the movement of the bar, the positioning of the
sensors in the moving bar... AP3
The integration error is obtained by:
AP - d-̂ v- KA , V ^" " AF -¿Al 1 — ¿X/i ~t~ / LXV • — . . . .
1 dA tt dF¡(12)
n i=\
The estimate of the área is A = 0.414 ± 0.005 m2 and AF¡/F¡= ± 3%, the error AP, is ± 4.3 %.
The dispersión of results when different methods of interpolation are used is almost
neglected, AP2=±0.1%, due to the soft shape of the flux distribution.
The positioning of the sensors in the bar and the movement of the bar also affect the final error.
Probably the bar speed isn't completely constant and the plañe scanned by it isn't parallel
completely to the receiver aperture. Nevertheless, it is quite realistic to consider AP3 « ± 1%.
Therefore, it is possible to obtain an estimation of the global error:
AP¡n =APl+AP2+APi<± 6% (13)
A Matlab program for the analysis of data has been prepared to obtain the flux distribution
onto the receiver aperture. Several interesting quantities as the total incident power, the valué
of the flux peak and its positioning referred to the center of the aperture are also obtained. In
the next pages an example of measurement analysis is presented.
J. Ballestrín 16
Direct heat-flux measurement system (MDF) for solar receiver evaluation
Total Power = 198.2 kW kW/m2
-0.4 -0.3 -0.2 -0.1 0 0.1 0.2
560
540
520
500
480
460
,440
i 420
i 400
380
360
Figure 15: Flux disíribution 2D
Last figure is a synthetic image obtained from a group of analog signáis such as been
described before; it represents the 2D-flux distribution onto the receiver aperture by 20
heliostats. The convolution of the contributions of all heliostats supplies the reproduction of
the solar disk as expected. Several relevant quantities associated to this image are:
® Flux peak = 564.7 kW/m2
o xmax =-0.001 m
» ymax = 0.053 m
o Total Power = 198.2 kW
a Power Error = ± 10.7 kW
• Power Error = ±5 .4%
« Flux Average = 478.8 kW/rn2
«• Energy = 0.09 kWli
o Scanning Time = 1.58 s
J. Ballestrín 17
Direct heat-flux measurement system (MDF) for solar receiver evaluation
In the next figure, the associated 3D-flux distribution is presented.
Flux distribution (kW/rn2) kW/m2
600-.
550.
500.
450.
400.
350 s
-
-
-
-
-
-
-
-
-
560
540
520
500
480
460
440
420
400
380
360
Figure 16: Flux distribution 3B
The incident solar power and the spatial flux distribution on the aperture of the volumetric
receiver Hitrec II are supplied by the above-mentioned MDF system. The first results
obtained during the evaluation of this solar receiver are presented including a sunrise-sunset
test.
DATE: 08/01/2001
GMT (hh:mm:ss)
10:41:2311:11:5611:22:1811:42:11
N° of heiiostats
10152025
Insolation (W/m2)
940957962960
Flux average (kW/m2)
303360479621
Flux peak (kW/m2)
362434565724
Incident power (kW)
126 + 7149 + 8198 ±11257 ±14
J. Ballestrín 18
Direct heat-flux measurement system (MDF) for solar receivers evaluation
DATE: 15/01/2001
GMT (hh:mm:ss)
9:56:1810:13:2610:27:4610:56:0511:09:0111:35:2011:47:1412:10:2512:39:4412:51:5513:04:0014:00:1514:21:1614:31:05
N° of heliostats
1015202525252525252525252727
Insoiation (W/m2)
850867890896907919911904820777762880780828
Flux average (kW/m2)
217345421530549581594567606580596553491546
Flux peak (kW/m2)
257426493635669696703656702684700641581656
Incident power (kW)
90 ±5143 ±8174 ±9
220 + 12227 ± 12241 ±13246 ±13235 ±13251 ± 14240 ±13247 ±13229 ±12203 ±11226 ±12
DATE: 17/01/2001
GMT (hh:mm:ss)
11:05:0311:18:4511:24:0911:33:5911:42:0811:49:1611:56:0712:22:2012:29:2112:59:2713:04:4713:16:0713:42:2514:10:5614:28:4614:40:44
N° of heliostats
25252525252525252525252525252825
Insoiation (Wlm2)
935940941945945950952959955942945944933908887887
Flux average (kW/m2)
560616621608640626650655659619632636635578609591
Flux peak (kW/m2)
715774785771807780813777806746746807759697731717
Incident power (kW)
232 ±13255 ± 14257 ± 14252 ± 14265 ± 14259 ±14269 ±15271 ±15273 + 15256 ± 14262 ± 14263 ± 14263 ±14239 ±13252 ± 14245 ±13
DATE: 23/01/2001
GMT (hh:mm:ss)
11:55:3112:00:5012:08:3312:16:0712:38:18
N° of heliostats
510202528
Insoiation (W/m2)
890300500650850
Flux average (kW/m2)
135161303526641
Flux peak (kW/m2)
158190374662814
Incident power (kW)
56 ±367 ±4125 ±7
218 ±12265 ± 14
DATE: 09/02/2001
GMT (hh:mm:ss)
10:51:2911:17:0111:42:3811:51:5812:55:2013:24:1913:34:5514:26:32
N° of heliostats
2525252524252525
Insoiation (W/m2)
960980989991990980967913
Flux average (kW/m2)
556595615627584576545535
Flux peak (kW/m2)
705701706737677702681661
incident power (kW)
230 ± 12246 ±13255 ± 14259 ± 14242 ±13239 ±13226 ±12221 ± 12
J. Ballestrín 19
Direct heat-flux measurement system (MDF) for solar receiver evaluation
DATE: 01/02/2001
GMT (hh:mm:ss)
9:20:519:26:129:30:509:34:569:40:1910:56:0611:07:2811:19:3711:31:4812:29:2612:40:2712:50:5213:04:5813:34:0313:53:4414:30:5214:52:08
N° of heliostats
510152025232323232323232324262626
Insolation (W/m2)
855865875880885945946946968964960956961943935913898
Flux average (kW/m2)
94227330402480541570562564584570576548553555556494
Flux peak (kW/m2)
131272390470560655676669674697672685661702711735644
Incident power (kW)
39 ±294 ±5137 ±7166 ±9199 ±11224 ±12236 ±13233 ±13233 ±13242 ±13236 ±13238 ±13227 ±12229 ±12230 ±12230 ±12205 ±11
DATE:02/02/2001
GMT (hh:mm:ss)
10:36:4110:42:1810:45:3110:53:2611:39:1811:52:4412:17:4412:33:0112:42:5913:09:09
N° of heliostats
6121824252525252525
Insolation (W/m2)
922925930935953964960965958947
Flux average (kW/m2)
154336442585579607603599590565
Flux peak (kW/m2)
178413514685675719705720703665
Incident power (kW)
64 ±3139 ±8183 ±10242 + 13240 ±13252 ±14250 + 14248 ±13244 ±13234 ±13
DATE:05/02/2001
GMT {hh:mm:ss)
9:42:159:47:529:51:5510:58:4311:10:4911:23:1411:38:2911:46:0412:16:4712:36:1812:54:1013:32:3413:49:14
N° of hellostats
8182528282727272627272930
Insolation (W/m2)
840850860916922927921919928935932914907
Flux average (kW/m2)
191385527626642629612631615621625585615
Flux peak (kW/m2)
228449620771743769725759729738734716740
Incident power (kW)
79 ±4159 ±9
218± 12259 ±14266 ± 14260 ±14253 ± 14261 ± 14255 ±14257 ±14259 ±14242 ±13255 ±14
DATE: 08/02/2001
GMT(hh:mm:ss)
10:59:3811:06:3911:25:12
N° of heliostats
262626
Insolation (W/m2)
881873875
Flux average (kW/m2)
565563559
Flux peak (kW/m2)
690683686
Incident power (kW)
234 ±13233 ±13231 ±13
J. Ballestrín 20
Direct heat-flux measurement system (MDF) for solar receiver evaluation
DATE: 13/02/2001
GMT (hh:mm:ss)
7:31:318:05:238:10:088:14:158:19:268:45:069:20:469:45:3510:15:3410:45:0811:15:5711:45:4712:45:0613:15:1214:46:4315:16:5615:22:3315:45:3515:49:4716:20:1016:46:2716:49:5417:18:16
N° of heliostats
2525252525252525252525252525252525252525252525
Insolation (W/m2)
49070973174676684390794392197810071004984969902870855814802709604588379
Flux average (kW/m2)
10623525025527534144252744360860662562161845741239733633224918716668
Flux peak (kW/m2)
11627929430232240354464452874273276472172153748247238938829522018989
Incident power (kW)
44 + 297 + 5104 ±6106 ±6114 + 6141 ±8183 ±10218 ± 12183 ±10252 ± 14251 ± 14259 ± 14257 ± 14256 ±14189 ±10171 ±9165 ±9139 ±8138±7103 ±677 ±469 ±428 ±2
13-2-2001 Sunríse - Sunset(25 hefiostats)
-•— Insolation
-o— Solar Power
£
250-
200-
150-
O
a.& ioo-ow
50-
1000
800 5)
io"3
600 <
400
10 11 12 13 14 15 16 17 18
GIVIT ( h )
Figure 17: Sunrise-Sunset of 13-2-2001
J. Ballestrín 21
Direct heat-flux measurement system (MDF) for solar receiver evaluation
All these measurements could be concentrated in one coefficient, D., that describes the global
behavior of the Solar Power Plant. The incident power onto the receiver aperture, O , depends
lineally on the number of heliostats, N, and the insolation, I. So, this quantity can be expressed
explicitly as a function of N and I:
Q^QN I A (14)
where A is the reflective área per heliostat, 39.95 ± 0.05 m2 and I the insolation in W/m2.
At the same time this coefficient depends implicitly on other parameters of difficult obtaining
as: heliostat beam quality, cosine factor, heliostat reflectivity, etc. This coefficient has been
obtained performing a fitting of the measured data during the test campaign:
Q = 2.648 lO^4 ±0.212 10"4
This coefficient is only valid around noon when the cosine factor has similar influence. Out of
the central hours of the day the cosine factor changes reducing the incident power onto the
receiver aperture.
FLUX & POWER PREDICTIQNS
H1TREC II VOLUMETRIC RECESVER
J. Ballestrín (2001, CIEMAT-PSA)
[ N° of heliostats | Insolation (W/m2) [ Flux average (kW/m2) | Flux peak (kW/m2) | Incident power (kW) |25 950 607 664 251
Error faand (kW)
271231
Figure 18: MDF Excel tool
The result is a simple Excel tool with two inputs that allows the operator to know the number of
heliostats required to maintain a fix power onto the receiver aperture for a certain insolation.
This kind of empirical tools will be welcome in the ftiture Solar Power Plants for the day-to-day
operation in opposition to the detailed codes more adequate during the design period of the
plant.
J. Ballestrín 22
Direct heat-flux measurement system (MDF) for solar receiver evaluation
6 SUMMARY
A direct flux measurement system, MDF, has been designed, constructed and mounted on top of
the SSPS-CRS tower at the Plataforma Solar de Almería (PSA) in addition to an indirect flux
measurement system based on a CCD camera. It's one of the main fiiture objectives to compare
systematically both measurements of the concentrated solar power, increasing in this way the
confidence in the estímate of this quantity. Today everything is prepared to perform the direct
flux measurement on the aperture of solar receivers: calorimeter array, data acquisition system
and software. The geometry of the receiver determines the operation and analysis procedures to
obtain the incident power onto the defined área.
The study of previous experiences with direct flux measurement systems has been useful to
define a new, simpler and more accurate system. A description of each component of the MDF
system is included, focusing on the heat-flux sensors or calorimeters, which enables these
measurements to be done in a few seconds without water-cooling.
The incident solar power and the spatial flux distribution on the aperture of the volumetric
receiver Hitrec II are supplied by the above-mentioned MDF system. The first results obtained
during the evaluation of this solar receiver have been presented including a sunrise-sunset test.
All these measurements have been concentrated in one coefficient that describes the global
behavior of the Solar Power Plant.
• Becker, M., Bohn, M., Gupta, B., Meinecke, W., "Solar Energy Concentrating
Systems", Applications and Technologies, 1995.
© Carasso, M., Becker, M. "Performance Evaluation Standars for Solar Central
Receivers". Springer-Verlag, 1990.
• Ajona, J.I., Balsa, P., Becker, M., Blanco, J, Blezinger, H, Macías, M., Malato, S.,
Martínez, D., Richter, C, Sánchez, M., Valverde, A., Weinrebe, G., Zarza, E.,
"Solar thermal test facilities", SolarPaces Report III-5/1995.
« Aguado, M., Ajona, J.I., Gómez, V., Heller, P., Kjibus, A., Neumann, A., Schiel,
W., Silva, M., Tamme, R., Zarza, E., "Solar thermal electricity generation",
Lectores from the summer school at the Plataforma Solar de Almería, The clean
way to genérate electricity and produce chemicals, July 1998.
J. Ballestrin 23
Direct heat-flux measurement system (MDF) for solar receiver evaluation
• Winter, Sizzmann y Vant-Hull: (Eds.), "Solar Power Plants". Springer-Verlag,
1991.
• Becker, M.; Gupta (eds.); Meinecke, W.; Bonn, M.,"Solar Energy Concentrating
Systems". Ed.: C.F.Müller, 1995.
o Becker y Funken (Eds); "Solar Thermal Energy Utilization. Germán Studies on
Technology and Applications". Springer-Verlag, 1998.
• Shikin, E; Plis, A; "Handbook on Splines for the User". CRC Press 1995.
Reports
• Ballestrín, J; Maillard, R; "Medida Directa de Flujo (MDF) en un receptor solar.
Diseño y puesta a punto". R-07/00 JBB-RM, 2000.
• Ballestrín, J; "Direct Flux Measuring system (MDF) for the Hitrec II receiver
evaluation". Solair project report TSRC/SOLAIR/ITE-02/2000. September 2000.
• Ballestrín, J; Borretzen; "First results of the Direct Flux Measurement system
(MDF)". Solair project report TSRC/SOLAIR/ITE-03/2001. February 2001.
o Hoffschmidt, B; Pitz-Paal, R; Bohmer, M; Fend, T; Rietbrock, P; "200 KWth open
volumetric air receiver (HitRec) of DLR reached 1000°C average outlet
temperature at PSA". IEA-SolarPACES on Solar Technology and Applications,
Odeillo, France, 1998.
• García, G., "Descripción del software del sistema de medida de flujo del receptor
volumétrico (MFV)". Internal report R-17/88GG, 1988.
• Diessner, F; "Operation manual for the measurement activities with Heat Flux
Distribution (HFD) system". DFVLR (Deutsche Forschungs- und Versuchsanstalt
für Luft- und Raumfahrt), Cologne, June 1981.
• Use of the Vatell Heat flux Microsensor. Vatell Corporation, September 1999.
• Thermateq"-nology. Technical notes. Vatell Corporation, September 1997, June
2000.
• National Instruments: "The Measurement and Automation", Catalog 2000.
o Biggs, F; Vittitoe, Ch; "The HELIOS model for the optical behavior of reflecting
solar concentrators". SAND76-0347, Sandia Laboratories, Alburquerque, USA,
1979.
J. Ballestrín 24
Direct heat-flux measurement system (MDF) for solar receiver evaluation
APPEND1X 1: CALIBRATION SHEETS
fATELL CORPORATION
Certifícate of Calibration
Model Number:Serial Number:
Date Calibrated:
Recalibration Due Date:
Sensor Coating:
HFM-7E/L0806
5-5-2000
5-5-2001
Zynolyte
Heat Flux MIcrosensor Calibration DataThe following coefficients are for use with equations in the document, "Use of Vatell Heat FluxMicrosensor Calibration Equations", enclosed. This document should be completely read toeflectively understand sensor measurements. These coefficients apply only to the sensor with theserial number above.
COEFF.
ab
cd
ef
gh*
VALUÉ
0.0
0.0
3.17522
-473.018
0.3'l4939
148.9717
-0.007623
196.8309
UN1TS
xlO"5
xlO"3
n/°cnuV/W/cm2/°C
uV/W/cm2
Resistance Temperature Sensor (RTS)Resistance (@ 22°C): 155 Q.Calibrated Range: 30°C-180°C
Heat Flux Sensor (HFS)Resistance (@ 22°C): 2.94 k Q.Calibrated Heat Flux: 12.963 W/cm2
Sensitivity ¡£ for incident heat flux based on an emissivity of 0.94 at 2 microns.
These calibrations were performed using instrumentswhose accuracy is traceable to the National Institute ofStandards and Technology (NIST) and followin;procedures set in the Vatell Quality Assurance Manual.
Calibrated
LAWRENCEW.LM6LEYNo. 16702
l-l-MAIL: V;II<.-1I(!!-IH.-V.IICI I IOMK l 'Aí i l : : hllp://\vwU'.C¡3.ncl/vaiell/ FAX: (540) 953-30 I O PIIÜNB: (540) 9(¡l-2O()!PO KOX C)(j. Cl IKlSTIANSUlilíC;. VA 24068 • 240 JENNELLE ROAD. CIIRISTIANSBURG. VA 24O7?,
J. Ballestrín 25
Direct heat-flux measurement system (MDF) for solar receiver evaluation
ATELL CORPORATION
Certifícate of Calibration
Model Number:Serial Number:Date Calibrated:Recalibration Due Date:Sensor Coating:
HFM-7E/L08074-27-20004-27-2001
Zynolyte
Heat Flux Mfcrosensor Calibration DataThe following coefiScients are for use with equations in the document, "Use of Vatell Heat FluxMicrosensor Calibration Equatíons", enclosed. This document should be completely read toeffectively understand sensor measurements. These coefficients apply only to the sensor with theserial number above.
COEFF.
abcdef
gh*
VALUÉ
0.0
0.0
3.29167
-489.062
0.303797
148.5755
0.130902
115.9932
UNÍTS
xlO"5
xlO"3
Q/°C
Q
uV/W/cm2/oC
uV/W/cm2
Resistance Temperature Sensor (RTS)Resistance (@ 22°C): 168 OCalibrated Range: 30° C -180° C
Heat Flux Sensor (HFS)Resistance (@ 22°C):Calibrated Heat Flux:
1.77 kQ12.373 W/cm2
: Sensitivity is for incident heat flux based on an emissivity of 0.94 at 2 microns.
These calibrations were performed using instmmentswhose accuracy is traceable to the National InstituteStandards and Technology (NIST) and followinprocedures set in the Vatell Quality Assurance Manual.
Cahbrated by;
1I-MAIL: vaicll<S'lx;v.nc:l l-IOMIi PAGlí: hlip:/Avw\v.G3.nei/vaielI/ FAX: (540) 953-3OR) PHONE: (540) fi(il-2()OiVQ BOX 66. CHHISTIANSUUKC;. VA 24068 • 240 JENNELLE ROAD. CHRISTIANSBURG. VA 24O73
J. Ballestrín 26
Direct heat-flux measurement system (MDF) for solar receiver evaluation
rATELL CORPORATION
Certifícate of Calibration
Model Number:Serial Number:Date Calibrated:Recalibration Due Date:Sensor Coating:
HFM-7E/L08084-27-20004-27-2001
Zynolyte
Heat Flux Microsensor Calibration DataThe foUowing coefficients are for use with equations in the document, "Use of VateU Heat FluxMicrosensor Calibration Equations", enclosed. This document should be completely read toeffectively understand sensor measurements. These coefficients.apply only to the sensor with theserial number above.
Resistance Temperature Sensor (RTS)Resistance (@ 22°C): 145 QCalibrated Range: 30° C -180° C
Heat Flux Sensor (HFS)Resistance (@ 22°C): 2.36 k D.
COEFF.
ab
cdef
gh*
VALUÉ •
0.0
0.0
3.38048
-471.91
0.295816
139.5983
0.1665
156.0635
UNITS
xlO"5
xlO"3
Í2/°C
nuV/W/cirf/°C
uVAV/cm2
Calibrated Heat Flux: 12.318 W/cmz
* Sensitivity is for incident heat flux based on an emissivity of 0.94 at 2 microns.
These calibrations were performed using instrumentswhose accuracy is traceable to the National InstituteStandares and Technology (NIST) and followinprocedures set in the Vatell Quality Assurance Manual.
Calibrated by:
LAWBEMCEW.UWSGIEYNo. 16702
E-MAIL: vaiell@bev.nel HOME PAG ti: hlip:/AV\vw.G3.nei/vatell/ FAX: (540) 953-3O1O PHONE: (540) ÍX5I-2OOIPO BOX 06, Cl IRISTIANSBURG. VA 24068 • 240 JENNELLE ROAD. CHRISTIANSBURG. VA 24073
J. Ballestrín 27
Direct heat-flux measurement system (MDF) for solar receiver evaluation
ATELL CORPORATION
Certifícate of Calibration
Model Number:Serial Number:Date Calibrated:Recalibration Due Date:Sensor Coating:
HFM-7E/L08155-5-20005-5-2001Zynolyte
Heat Flux Microsensor Calibration DataThe following coefficients are for use with equations in the document, "Use of Vatell Heat FluxMicrosensor Calibration Equations", enclosed. This document should be completely read to
effectively understand sensor measurements. These coefHcients apply only to the sensor with the
serial number above.
COEFF.
abcd
ef
9h*
VALUÉ
0.0
0.0
3.73253
-486.369
0.267915
130.3053
0.122747
117.7029
UNITS
xlO"5
xlO"3
n/°cQ.
uV/W/cm2/°C
uVAV/cm2
Resistance Temperature Sensor (RTS)Resistance (@ 22°C): 134 QCalibrated Range: 30° C - 180° C
Heat Flux Sensor (HFS)Resistance (@ 22°C):Calibrated Heat Flux:
4.72 k Q
12.929 W / c m 2
* Sensitivity is for incident heat flux based on an emissivity of 0.94 at 2 microns.
These calibrations were performed using instrumentswhose accuracy is traceable to the National Institute ofStandards and Technology (NIST) and followiniprocedures set in the Vatell Quality Assurance Manual.
Calibrated by:y
(7
F . - M A I I . : V Í I K ' I K P I X ' V . I K ' 1 I l ( i M I - ; P A l i l - l : I ) H | > : . ' / w \ v \ v . ( YA. I K . - ¡ / V ; I K ' 1 I / l r . - \ X : i r > 4 O | í ) r > ; í - 3 ( > I o I ' I l ( ) N [ i : ( f i - H ) ] < H ¡ I - l í o u l
i 'onoxiiii. ci ii-;isTiA\sni'fic;. \v\ J-KKÍK • ^-K).II:.NNI-:LLI; HOAU. CHRISTIANSBUKG. \V\ 2-1.07;',
J. Ballestrín 28
Direct heat-flux measurement system (MDF) for solar receiver evaluation
r/ATELL CORPORATION
Certifícate of Calibration
Model Number:Serial Number:Date Calibrated:Recalibration Due Date:Sensor Coating:
HFM-6C/L05855-5-20005-5-2001Zynolyte
Heat Flux MIcrosensor Callbratlon DataThe following coefficients are for use with equations in tfae document, "Use of Vatell Heat FluxMicrosensor Calibration Equations", enclosed. This document should be completely read toeffectively understand sensor measurements. These coefBcients' apply only to the sensor \vith theserial number above.
Resistance Temperature Sensor (RTS)Resistance (@ 22°C): 84 • D.Calibrated Range: 30° C -180° C
COEFF.
abcdef
gh*
VALUÉ
0.0
0.0
5.51703
-438.464
0.181257
79.4746
0.050514
57.1253
UN1TS
xlO"5
xlO"3
Q/°C
D.uV/W/em2/°C
uV/W/cm2
Heat Flux Sensor (HFS)Resistance (@ 22°C):Calibrated Heat Flux:
2.73 k Q.
12.951 W / c m 2
* Sensitivity is for incident heat flux based on an ernissivity of 0.94 at 2 microns.
These calibrations were performed using iastrumentswhose accuracy is traceable to the National Institute ofStandards and Technology (NIST) and followinprocedures set in the Vatell Quality Assurance Manual.
Calibrated by:
LAWRENCEW.UKGLEYNo. 16702
E-MAIL: vaiell<s>l)c:v.nri HOMI-; PACJl-I: l)tl|J:/Av\v\v.G3.ncl/vaiell/ FAX: (540) 953-30 I O PI-IONE: (540) 9U1-2CKHPü BOX CiCi. Cl IRISTIANSBLJRG. VA 24068 • 240 JENNELLE ROAD. CHRISTIANSBURG. VA 24O73
J. Ballestrín 29
Direct heat-flux measurement system (MDF) for solar receiver evaluation
r/ATELL CORPORATION
Certifícate of CalibrationModel Number:Serial Number:
Date Calibraíed:
Recalibration Due Date:
Sensor Coating:
HFM6CL0838
7-20-2000
7-20-2001
Zynolyte
Heat Flux Microsensor Callbration DataThe following coefficients are for use with equations in the document, "Use of Vateil Heat FluxMicrosensor Calibration Equations", eaclosed. This document should be completely read toeffectively understand sensor measurements. These coefficients apply only to tlie sensor with theserial number above.
Resistance Temperatura Sensor (RTS)Resistance (@ 22°C): 130 OCalibrated Range: 30°C-180°C
Heat Flux Sensor (HFS)Resistance (@ 22°C): 3.28 k f l
COEFF.
abcd
ef
gh*
VALUÉ
0.00.0
3.81764
-475.3660.261942
124.5183
0.040492
.46.9813
UNITS
xlO-5
x l0 J
n/°cnuV/W/cm7°C
uV/W/cm2
Calibrated Heat Flux: 12.61 W/crrf
' Sensitivity is for incident heat flux based on an emissivity of 0.94 at 2 microns.
These calibrations were performed using instrumentswhose accuracy is traceable to the National Institute ofStandards and Technology (NIST) and followingprocedures set in tlie Vateil Quality Assurance Manual.
Calibrated by:
li-MAIL: \-;iK-IK«i)fV.lu-l IIOMlí i\\< ¡I-.: hll| >:/7\v\v\v.r,:', ncl/Víltcll/ lv\X: I>HII !).">>:«> lo l'l l ( l \ ' ! i : 154OI ÍM¡ I -2(11) Ii'O BOX (¡(i. Ci 1HISTIANSHI¡I«¡. VA 2-KK)S • 2-U) JENNIii.LH HOAL). Cl IRISTIANSBL'!«'.. VA 2-KI7.'.
J. Ballestrin 30
Direct heat-flux measurement system (MDF) for solar receiver evaluation
'ATELL CORPORATION
Certifícate of Calibration
Model Number:Serial Number:
Date Calibrated:
Recalibration Due Date:
Sensor Coating:
HFM7EL0817
7-26-2000
7-26-2001
Zynolyte
Heat Flux Microsensor Calibration DataThe following coefficients are for use with equations in the document, "Use of Vatell Heat FluxMicrosensor Calibration Equations", enclosed. This document should be completely read toefiectively understand sensor measurements. These coefficients apply only to the sensor with theserial number above.
Resistance Temperature Sensor (RTS)Resistance (@ 22°C): 130 fiCalibrated Range: 30°C-180°C
Heat Flux Sensor (HFS)Resistance (@ 22°C): 4.26 k O
COEFF.
ab
cd
ef
gh*
VALUÉ
0.0
0.0
3.91142-487.196
0.255661
124.5573
0.190739
186.306
UN1TS
xlO'5
xl0°
O/°C
Q
uV/W/cm2/°CuV/W/cm*
Calibrated Heat Flux: 12.627 W/crrf
* Sensitivity is for incident heat flux based on an emissivity of 0.94 at 2 microns.
These calibrations were performed using instrumentswhose accuracy is traceable to the National Institute ofStandards and Technology (NIST) and followingíprocedures set in the Vatell Quality Assurance Manual. \ LAWREHCE W. IAMSLEY'
No. 16702
Calibrated by:
I:.-M.\!l.- VilU'llwhrv ncl I U i.MI-. I '.M ¡l-l llll|>://\v\v\\\( ü¡ Jld/valcl l / FAX. ITI-KII 9G:i-."!( 111) I'I lONlí: (fi-Mll !«i i -2(HHI'O B( IX <,!.. ( I [l-;iSIl.-\NSIU:H<i. \V\ J-VlKiK • 2-Kl J I lNNI- lUiHOAD. U IHISTIANSBUI-ÍC i. VA 1Í-I-O7:!
J. Ballestrín 31
Direct heat-flux measurement system (MDF) for solar receiver evaluation
fATELL CORPORATION
Certifícate of CalibrationModel Number:Serial Number:Date Calibrated:Recalibration Due Date:Sensor Coating:
HFM7EL08527-27-20007-27-2001Zynolyte
Heat Flux Microsensor Calibration DataThe following coefficients are for use with equations in the document, "Use of Vatell Heat FluxMicrosensor Calibration Equations", enclosed. This document should be completely read toefíectively understand sensor measurements. These coefficients apply only to the sensor with theserial number above.
COEFF.
ab
cd
e
f
9h*
VALUÉ
0.0
0.0
3.77309-490.257
0.265035
. 129.9353
0.093488
126.734
UN1TS
xlO"
xlO'3
n/°co.uV/W/cm2/°CuV/W/crrf
Resistance Temperatura Sensor (RTS)Resistance (@ 22°C): 135 OCalibrated Range: 30°C-180°C
Heat Flux Sensor (HFS)Resistance (@ 22°C):Calibrated Heat Flux:
3.18 k Q.12.635 W/cm 2
• Sensitivity is for incident heat flux based on an emissivity of 0.94 at 2 microns.
These calibrations were performed using instruments
whose accuracy is traceable to the National Institute of
Standards and Technology (NIST) and following
procedures set in the Vatell Quality Assurance Manual.
Calibrated I
I--MAII.- v;ilrl|í"-l)i-v.|j<-t IUIMI-: l'ACil-:. hll|)://ww\v.(;:i.l lcl/v;ilrll/ FAX: (."4OI <);"">:•!-:!<> I (> HI-IONli: lf>4()| !i ' o i i o x (i(>. <:i i n i s n . \ N s i ' , r i « i . V A 2 4 ( M J S • a-K) JI:NNI-:LI.I-: K O A U .
J. Ballestrín 32
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