Stress in shaped glass evacuated collectors

Conference · Sun Oct 01 04:00:00 EDT 1995

OSTI ID:109863

Garrison, J D ^[1]; Fischer-Cripps, A ^[2]

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1. San Diego State Univ., CA (United States)
2. National Inst. of Standards and Technology, Gaithersburg, MD (United States)

Shaped glass evacuated collectors have the lower portion of the vacuum envelope formed with a truncated CPC shape and the internal glass surface silvered. The silvered surface concentrates the incoming solar radiation onto an internal absorbing tube. The upper portion of the collector is a window to pass the solar radiation in to the absorbing tube. A computer program using analytical equations is used to design these collectors while keeping the glass tensile stress from evacuation below acceptable limits. A finite element computer program is used to test the accuracy of the analytical calculations. The two calculations agree within about 1 MPa. Standard heat transfer methods are used to estimate the temperature distribution around the collector during stagnation. This temperature distribution is used in the finite element program to determine the thermal stress. The maximum thermal stress during stagnation is an order of magnitude lower than the stress from evacuation.

• OSTI ID: 109863
• Report Number(s): CONF-950725--; ISBN 0-89553-167-4
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
CALCULATION METHODS
COMPUTERIZED SIMULATION
PARABOLIC TROUGH COLLECTORS
TEMPERATURE DISTRIBUTION
THERMAL STRESSES