In current designs of parabolic trough collectors for concentrating solar power plants, the absorber tube is manufactured in segments that are individually insulated with glass vacuum jackets. During the lifetime of a power plant, some segments lose vacuum and thereafter suffer from significant convective heat loss. An alternative to this design is to use a vacuum pump to actively maintain low pressure in a long section of absorber with a continuous vacuum jacket. A detailed thermal model of such a configuration is needed to inform design efforts for such a receiver. This paper describes a combined conduction, convection, and radiation heat transfer model for a receiver that includes the effects of nonuniform solar flux on the absorber tube and vacuum jacket as well as detailed analysis of conduction through the rarefied gas in the annular gap inside the vacuum jacket. The model is implemented in commercial CFD software coupled to a Monte Carlo ray-tracing code. The results of simulations performed for a two-dimensional cross-section of a receiver are reported for various conditions. The parameters for the model are chosen to match the current generation of parabolic trough receivers, and the simulation results correspond well with experimental measurements.

Issue Section:
Research Papers
Keywords:
computational fluid dynamics, convection, design engineering, flow simulation, heat conduction, heat losses, heat radiation, Monte Carlo methods, pipe flow, radiative transfer, rarefied fluid dynamics, solar absorber-convertors, solar power stations, vacuum pumps
Topics:
Convection, Heat conduction, Heat losses, Heat transfer, Parabolic troughs, Radiation (Physics), Solar energy, Temperature, Vacuum, Computational fluid dynamics, Glass, Simulation, Vacuum equipment, Pressure, Computer software, Numerical analysis

References

1.
Price
,
H.
 et al., 2002, “
Advances in Parabolic Trough Solar Power Technology
,”
J. Sol. Energy Eng.
,
124
(
2
), pp.
109
–
125.
Crossref
Search ADS
 
2.
Lüpfert
,
E.
 et al., 2008, “
Experimental Analysis of Overall Thermal Properties of Parabolic Trough Receivers
,”
J. Sol. Energy Eng.
,
130
(
2
), p.
021007
.
Crossref
Search ADS
 
3.
Price
,
H.
 et al., 2006, “
Field Survey of Parabolic Trough Receiver Thermal Performance
,”
Proceedings of the ASME International Solar Energy Conference
,
ISEC2006-99167, ASME
, pp.
109
–
116.
4.
Forristall
,
R.
, 2003,
“Heat Transfer Analysis and Modeling of a Parabolic Trough Solar Receiver Implemented in Engineering Equation Solver,”
National Renewable Energy Laboratory
,
Golden, CO
, Report No. NREL/TP-550-34169.
5.
Eck
,
M.
,
Feldhoff
,
J. F.
, and
Uhlig
,
R.
, 2010, “
Thermal Modelling and Simulation of Parabolic Trough Receiver Tubes
,”
Proceedings of the ASME 2010 4th International Conference on Energy Sustainability
,
ES2010-90402, ASME
,
2
, pp.
659
–
666.
6.
Sharipov
,
F.
, and
Seleznev
,
V.
, 1998, “
Data on Internal Rarefied Gas Flows
,”
J. Phys. Chem. Ref. Data
,
27
(
3
), pp.
657
–
706.
Crossref
Search ADS
 
7.
Sharipov
,
F.
, 2004, “
Data on the Velocity Slip and Temperature Jump Coefficients
,”
Proceedings of the 5th International Conference on Thermal and Mechanical Simulation and Experiments in Micro-Electronics and Micro-Systems
, pp.
243
–
249.
8.
Sharipov
,
F.
, 2003, “
Application of the Cercignani–Lampis Scattering Kernel to Calculations of Rarefied Gas Flows II. Slip and Jump Coefficients
,”
Eur. J. Mech. B/Fluids
,
22
(
2
), pp.
133
–
143.
Crossref
Search ADS
 
9.
Burkholder
,
F.
, and
Kutscher
,
C.
, 2009,
“Heat Loss Testing of Schott’s 2008 PTR70 Parabolic Trough Receiver,”
National Renewable Energy Laboratory
,
Golden, CO
, Report No. NREL/TP-550-45633.
10.
Churchill
,
S. W.
, and
Bernstein
,
M.
, 1977, “
A Correlating Equation for Forced Convection From Gases and Liquids to a Circular Cylinder in Crossflow
,”
J. Heat Transfer
,
99
(
2
), pp.
300
–
306.
Crossref
Search ADS
 
11.
Burkholder
,
F.
, and
Kutscher
,
C.
, 2008,
“Heat-Loss Testing of Solel’s UVAC3 Parabolic Trough Receiver,”
National Renewable Energy Laboratory
,
Golden, CO
, Report No. NREL/TP-550-42394.
12.
Churchill
,
S. W.
, and
Chu
,
H. H. S.
, 1975, “
Correlating Equations for Laminar and Turbulent Free Convection From a Horizontal Cylinder
,”
Int. J. Heat Mass Transfer
,
18
(
9
), pp.
1049
–
1053.
Crossref
Search ADS
 
13.
Kennedy
,
C. E.
, 2008, “
Progress to Develop an Advanced Solar-Selective Coating
,”
Proceedings of the 14th Biennial CSP SolarPACES Symposium
.
Copyright © 2011
 by American Society of Mechanical Engineers
You do not currently have access to this content.