This study focuses on thermochemical cavity-type reactor, with a reactive material directly irradiated by concentrated solar energy. General tendencies of reactor performance are analyzed as a function of the reactor geometry. The objective is to define a simplified model that can be adapted easily to different reactor designs or different operating conditions. For this reason, the chemical reaction is not precisely fixed but rather characterized by a reaction temperature and a useful power consumed by the endothermic reaction, inside the reactive material. In order to increase the efficiency, two new reactor designs are proposed. These designs allow obtaining a nonuniform distribution of the useful power consumed by the reaction with the depth in a circular cylindrical cavity (z-axis). This is done in two ways: by varying the reactive material thickness along the axis or by varying its density at a constant thickness. The results show that these reactor concepts lead to a more uniform temperature distribution along the z-axis and a diminution of the heat losses. Thus, the reactor efficiency can increase significantly. The results of the simplified model can be used as a system predesign. A more accurate CFD model could be used afterward to refine the optimal shape.

References

References
1.
Steinfeld
,
A.
, and
Meier
,
A.
, 2004,
Encyclopedia of Energy
, Vol. 5, pp.
623
637
,
Elsevier
,
NewYork
.
2.
Petrasch
,
J.
,
Osch
,
P.
, and
Steinfeld
,
A.
, 2009, “
Dynamics and Control of Solar Thermochemical Reactors
,”
Chem. Eng. J.
,
145
(
3
), pp.
362
370
.
3.
Wieckert
,
C.
,
Palumbo
,
R.
, and
Frommherz
,
U.
, 2004, “
A Two-Cavity Reactor for Solar Chemical Processes: Heat Transfer Model and Application to Carbothermic Reduction of ZnO
,”
Energy
,
29
(
5–6
), pp.
771
787
.
4.
Wieckert
,
C.
,
Frommherz
,
U.
,
Kräupl
,
S.
,
Guillot
,
E.
,
Olalde
,
G.
,
Epstein
,
M.
,
Santén
,
S.
,
Osinga
,
T.
, and
Steinfeld
,
A.
, 2007, “
A 300kW Solar Chemical Pilot Plant for the Carbothermic Production of Zinc
,”
ASME J. Sol. Energy Eng.
,
129
, pp.
190
196
.
5.
Piatkowski
,
N.
,
Wieckert
,
C.
, and
Steinfeld
,
A.
, 2009, “
Experimental Investigation of a Packed-Bed Solar Reactor for the Steam-Gasification of Carbonaceous Feedstocks
,”
Fuel Process. Technol.
,
90
(
3
), pp.
360
366
.
6.
Meier
,
A.
,
Bonaldi
,
E.
,
Cella
,
G. M.
,
Lipinski
,
W.
, and
Wuillemin
,
D.
, 2006, “
Solar Chemical Reactor Technology for Industrial Production of Lime
,”
Sol. Energy
,
80
(
10
), pp.
1355
1362
.
7.
Roeb
,
M.
,
Sattler
,
C.
,
Klüser
,
R.
,
Monnerie
,
N.
,
De Oliveira
,
L.
,
Konstandopoulos
,
A. G.
,
Agraphiotis
,
C.
,
Zaspalis
,
V. T.
,
Nalbandian
,
L.
,
Steele
,
A.
, and
Stobbe
,
P.
, 2006, “
Solar Hydrogen Production by a Two-Step Cycle Based on Mixed Iron Oxides
,”
Sol. Energy Eng.
,
128
, pp.
125
133
.
8.
Müller
,
R.
,
Haeberling
,
P.
, and
Palumbo
,
R.
, 2009, “
Further Advances Toward the Development of a Direct Heating Solar Thermal Chemical Reactor for the Thermal Dissociation of ZnO(s)
,”
Sol. Energy
,
80
(
5
), pp.
500
511
.
9.
Hauater
,
P.
,
Moeller
,
S.
,
Palumbo
,
R.
, and
Steinfeld
,
A.
, 1999, “
The Production of Zinc by Thermal Dissociation of Zinc Oxide—Solar Chemical Reactor Design
,”
Sol. Energy
,
67
, pp.
161
167
.
10.
Abanades
,
S.
,
Charvin
,
P.
, and
Flamant
,
G.
, 2007, “
Design and Simulation of a Solar Chemical Reactor for the Thermal Reduction of Metal Oxides: Case Study of Zinc Oxide Dissociation
,”
Chem. Eng. Sci.
,
62
(
22
), pp.
6323
6333
.
11.
Hahm
,
T.
,
Schmidt-Traub
,
H.
, and
Leβmann
,
B.
, 1998, “
A Cone Concentrator for High-Temperature Solar Cavity-Receivers
,”
Sol. Energy
,
65
(
1
), pp.
33
41
.
12.
Steinfeld
,
A.
, and
Schubnell
,
M.
, 1993, “
Optimum Aperture Size and Operating Temperature of a Solar Cavity-Receiver
,”
Sol. Energy
,
50
, pp.
19
25
.
13.
Palumbo
,
R.
,
Keunecke
,
M.
, Mö
ller
,
S.
, and
Steinfeld
,
A.
, 2004, “
Reflection on the Design of Solar Thermal Chemical Reactors: Thoughts in Transformation
,”
Energy
,
29
, pp.
727
744
.
14.
Harris
,
J. A.
, and
Lenz
,
T. G.
, 1985, “
Thermal Performance of Solar Concentrator/Cavity Receiver Systems
,”
Sol. Energy
,
34
(
2
), pp.
135
142
.
15.
Shuai
,
Y.
,
Xia
,
X. L.
, and
Tan
,
H. P.
, 2007, “
Radiation Performance of Dish Solar Concentrator/Cavity Receiver Systems
,”
Sol. Energy
,
82
(
1
), pp.
13
21
.
16.
Tescari
,
S.
,
Neveu
,
P.
, and
Mazet
,
N.
, 2010, “
Thermochemical Solar Reactor: Simplified Method for the Geometrical Optimization at a Given Incident Flux
,”
Int. J. Chem. React. Eng.
,
8
(
24
), pp.
1
17
.
17.
Charvin
,
P.
,
Abanades
,
S.
,
Neveu
,
P.
,
Lemont
,
F.
, and
Flamant
,
G.
, 2008, “
Dynamic Modeling of a Volumetric Solar Reactor for Volatile Metal Oxide Reduction
,”
Chem. Eng. Res. Des.
,
86
(
11
), pp.
1216
1222
.
18.
Z’graggen
,
A.
,
Haueter
,
P.
,
Trommer
,
D.
,
Romero
,
M.
, De
Jesus
,
J. C.
, and
Steinfeld
,
A.
, 2006, “
Hydrogen Production by Steam Gasification of Petroleum Coke Using Concentrated Solar Power-II. Reactor Design, Testing and Modelling
,”
Int. J. Hydrogen Energy
,
31
(
6
), pp.
797
811
.
19.
Azoumah
,
Y.
,
Mazet
,
N.
, and
Neveu
,
P.
, 2004, “
Constructal Network for Heat and Mass Transfer in a Solid-Gas Reactive Porous Medium
,”
Int. J. Heat Mass Transfer
,
47
(
14–16
), pp.
2961
2970
.
20.
Azoumah
,
Y.
,
Neveu
,
P.
, and
Mazet
,
N.
, 2007, “
Optimal Design of Thermochemical Reactors Based on Constructal Approach
,”
AlChE J.
,
53
(
5
), pp.
1257
1266
.
21.
Tescari
,
S.
, 2010, “
Optimisation géométrique dérivée de l’approche constructale pour réacteurs thermochimiques sous rayonnement solaire concentré
,” Ph.D. thesis, Université de Perpignan, France, Septembre.
22.
Leuenberger
,
H.
, and
Person
,
R. A.
, 1956, “
Compilation of Radiation Shape Factors for Cylindrical Assemblies
,” Paper No. 56-A-144.
23.
Buschman
,
A.
, and
Pittman
,
C. M.
, 1961, “
Configuration Factors for Exchange of Radiant Energy Between Axisymmetrical Sections of Cylinders, Cones, and Hemispheres and their Bases
,” Report No. NASA TN D-944.
24.
Modest
,
F. M.
, 2003,
Radiative Heat Transfer
,
2nd ed.
,
Academic
,
San Diego.
25.
Gokon
,
N.
,
Murayama
,
H.
,
Nagasaki
,
A.
, and
Kodama
,
T.
, 2009, “
Thermochemical Two-Step Water Splitting Cycles by Monoclinic ZrO2-Supported NiFe2O4 and Fe3O4 Powders and Ceramic Foam Devices
,”
Sol. Energy
,
83
, pp.
527
537
.
You do not currently have access to this content.