In high-temperature solar-thermal systems the conversion of solar to thermal energy requires a radiation absorbing surface to transfer the radiative solar energy to the working fluid. The present study focuses on the generation of a moving radiation absorber using particles suspended in the working fluid. Three methods of particle entrainment in a gas were investigated. Elutriating fine particles from a spouted bed was found to be the preferred method. The diameter range of the entrained carbon black particles was 0.030-25μm, with 99.7% of the particles having an equivalent diameter less than 1μm, and 48% of the projected surface area was due to agglomerated particles with average equivalent diameter >5μm. The moving radiation absorber was tested in a solar receiver using nitrogen as a working fluid. The inner wall temperatures in the receiver cavity were below the gas exit temperature, which shows that the bulk heat transfer from the incoming solar radiation to the gas takes place via the moving radiation absorbing particles.

1.
Pitz-Paal
,
R.
,
Hoffschmidt
,
B.
,
Boehmer
,
M.
, and
Becker
,
M.
, 1997, “
Experimental and Numerical Evaluation of the Performance and Flow Stability of Different Types of Open Volumetric Absorbers under Non-Homogeneous Irradiation
,”
Sol. Energy
0038-092X,
60
(
3∕4
), pp.
135
150
.
2.
Karni
,
J.
,
Kribus
,
A.
,
Doron
,
P.
, and
Rubin
,
R.
, 1997, “
The DIAPR, A High Pressure, High Temperature Solar Receiver
,”
ASME J. Sol. Energy Eng.
0199-6231,
119
, pp.
74
78
.
3.
Levy
,
M.
,
Rubin
,
R.
,
Rosin
,
H.
, and
Levitan
,
R.
, 1992, “
Methane Reforming by Direct Solar Irradiation of the Catalyst
,”
Energy
0360-5442,
17
(
8
), pp.
749
756
.
4.
Flamant
,
G.
, 1982, “
Theoretical and Experimental Study of Radiant Heat Transfer in a Solar Fluidized-Bed Receiver
,”
AIChE J.
0001-1541,
18
(
4
), pp.
529
535
.
5.
Hunt
,
A. J.
, and
Brown
,
C. T.
, “
Solar Testing of the Small Particle Heat Exchanger
,” LBL-16497,
Lawrence Berkley Laboratory
, 1982.
6.
Bertocchi
,
R.
,
Karni
,
J.
, and
Kribus
,
A.
, 2004, “
Experimental Evaluation of a Non-Isothermal High Temperature Solar Particle Receiver
,”
Energy
0360-5442,
29
, pp.
687
700
.
7.
Trommer
,
D.
,
Hirsch
,
D.
, and
Steinfeld
,
A.
, 2004, “
Kinetic Investigation of the Thermal Decomposition of CH4 by Direct Irradiation of a Vortex-Flow Laden With Carbon Particles
,”
Int. J. Hydrogen Energy
0360-3199,
29
(
6
), pp.
627
633
.
8.
Hunt
,
A. J.
, and
Brown
,
C. T.
, “
Solar Testing of the Small Particle Heat Exchanger (SPHER)
,” LBL-16497,
Lawrence Berkeley Laboratory
, 1982.
9.
Funken
,
K.-H.
,
Luepfert
,
E.
,
Hermes
,
M.
,
Bruehne
,
K.
, and
Pohlmann
,
B.
, 1999, “
Oxidation Rates of Carbon Black Particles Exposed to Concentrated Sunlight
,”
Sol. Energy
0038-092X,
65
(
1
), pp.
15
19
.
10.
Dahl
,
J.
,
Buechler
,
K. J.
,
Weimer
,
A. W.
,
Lewandowski
,
A.
, and
Bingham
,
C.
, 2004, “
Solar-Thermal Dissociation of Methane in a Fluid-Wall Aerosol Flow Reactor
,”
Int. J. Hydrogen Energy
0360-3199,
29
, pp.
725
736
.
11.
Hunt
,
A. J.
,
Ayer
,
J.
,
Hull
,
P.
,
McLaughin
,
R.
,
Miller
,
F.
,
Noring
,
J.
,
Russo
,
R. E.
, and
Yuen
,
W.
, “
Solar Radiant Heating of Gas-Particle Mixtures. FY 1984 Summary Report
,” LBL-20447,
Lawrence Berkley Laboratory
, 1986.
12.
Bertocchi
,
R.
, 2002, “
Carbon Particle Cloud Generation for a Solar Particle Receiver
,”
ASME J. Sol. Energy Eng.
0199-6231,
124
, pp.
230
236
.
13.
Milioli
,
F. E.
, and
Foster
,
P. J.
, 1995, “
Entrainment and Elutriation Modeling in Bubbling Fluidized Beds
,”
Powder Technol.
0032-5910,
83
, pp.
233
243
.
14.
Geldart
,
D.
, 1973, “
Types of Gas Fluidization
,”
Powder Technol.
0032-5910,
7
, pp.
285
292
.
15.
Kogan
,
A.
,
Kogan
,
M.
, and
Barak
,
S.
, 2005, “
Production of Hydrogen and Carbon by Solar Thermal Methane Splitting III. Fluidization, Entrainment and Seeding Powder Particles into a Volumetric Solar Receiver
,”
Int. J. Hydrogen Energy
0360-3199,
30
(
1
), pp.
35
43
.
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