0
Research Papers

Numerical Analysis of Heat Loss From a Parabolic Trough Absorber Tube With Active Vacuum System

[+] Author and Article Information
Matthew Roesle, Volkan Coskun, Aldo Steinfeld

Department of Mechanical and Process Engineering,  ETH Zurich, Sonneggstrasse 3, 8092 Zurich, Switzerlandmroesle@ethz.chDepartment of Mechanical and Process Engineering,  ETH Zurich, Sonneggstrasse 3, 8092 Zurich, Switzerland;andSolar Technology Laboratory,  Paul Scherrer Institute, 5232 Villigen PSI, Switzerland e-mail:  aldo.steinfeld@ethz.chmroesle@ethz.ch

J. Sol. Energy Eng 133(3), 031015 (Jul 28, 2011) (5 pages) doi:10.1115/1.4004276 History: Received May 06, 2011; Accepted May 11, 2011; Published July 28, 2011; Online July 28, 2011

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.

FIGURES IN THIS ARTICLE
<>
Copyright © 2011 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Parabolic trough receiver [1]

Grahic Jump Location
Figure 2

Radial distribution of incident solar flux on absorber tube and vacuum jacket

Grahic Jump Location
Figure 3

Heat loss as a function of temperature for irradiated and unirradiated receivers

Grahic Jump Location
Figure 4

Glass temperature as a function of receiver temperature for irradiated and unirradiated receivers

Grahic Jump Location
Figure 5

Circumferential temperature distributions in (a) the absorber tube and (b) vacuum jacket

Grahic Jump Location
Figure 6

Conduction heat loss from irradiated and unirradiated receivers with air with P = 1 Pa in the annular gap

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In