Evaluation of the evacuated solar annular receivers used at the midtemperature solar systems test facility (MSSTF)
Experimental studies at the Sandia/DOE Midtemperature Solar Systems Test Facility (MSSTF) using the parabolic-cylindrical collector field subsystem are described. Tests evaluated vacuum integrity characteristics of ten glass-to-metal sealed concentric-cylinder receivers installed at the MSSTF in May 1977. Additional testing measured heat-loss reductions and related collector performance gains possible by annulus gas evacuation. Structural defects in four receivers and gas desorption from the receiver tubes at temperatures > 470/sup 0/K necessitated continuous annulus gas evacuation. Pressure rises of 1.8 x 10/sup -4/ Pa/s and 2.2 x 10/sup -2/ Pa/s, measured with receiver tube surfaces at 443/sup 0/K and 578/sup 0/K, respectively, are indicative of the outgassing. One-sun heat-loss and collector efficiency tests were performed with air-filled annular spaces maintained at 8.379 x 10/sup 4/ Pa (atmospheric pressure) and at pressures < 10 Pa. Overall collector efficiency improved by 3.5 to 9% and one-sun heat losses were reduced by 20 to 50%, depending upon operating temperature, annulus pressures, and insolation. Failure of the receiver assemblies to maintain annulus pressures below 1 Pa precluded expected overall efficiency improvements of 11 to 12%. Further, onsite vacuum maintenance was proved unfeasible because of the extensive pumpout manifolding and the additional manpower, parasitic energy, and capital equipment costs required.
- Research Organization:
- Sandia Labs., Albuquerque, NM (USA)
- DOE Contract Number:
- EY-76-C-04-0789
- OSTI ID:
- 6082886
- Report Number(s):
- SAND-78-0983
- Country of Publication:
- United States
- Language:
- English
Similar Records
Heat loss reduction techniques for annular solar receiver designs
Utilization of heavy fill gases in annular solar receiver geometries for heat loss reduction
Related Subjects
141000* -- Solar Collectors & Concentrators
COMPUTERIZED SIMULATION
CONCENTRATING COLLECTORS
COST
DEFECTS
DEGASSING
EFFICIENCY
ENERGY LOSSES
EVACUATED COLLECTORS
EVACUATED TUBE COLLECTORS
HEAT LOSSES
INSOLATION
LOSSES
MATHEMATICAL MODELS
MEDIUM VACUUM
PARABOLIC COLLECTORS
PARABOLIC TROUGH COLLECTORS
PERFORMANCE
PERFORMANCE TESTING
PRESSURE MEASUREMENT
SIMULATION
SOLAR ABSORBERS
SOLAR COLLECTORS
SOLAR RECEIVERS
TEST FACILITIES
TESTING
TUBES