Techniques for reducing thermal conduction and natural convection heat losses in annular receiver geometries
Analytical and experimental work has been undertaken to analyze thermal conduction and natural convection heat losses in annular receiver geometries. Techniques studied for reducing conduction heat loss include evacuation of the annulus gas, oversizing of the annular space while maintaining slight vacuum levels, and use of gases other than air in the annular space. For the geometry considered, total heat loss reductions of 10 percent to 50 percent may be obtained depending on the means by which the conduction heat loss is limited. In addition, natural convection studies considering the effects of nonuniform temperature distributions and eccentric cylinders are discussed. The numerical analysis performed indicates that highly nonuniform temperature distributions are required to appreciably affect the natural convection process between concentric cylinders and that rather large eccentricities cause only a slight increase in natural convection heat transfer.
- Research Organization:
- Fluid Mechanics and Heat Transfer Division, Sandia Laboratories, Albuquerque, N. M. 87185
- OSTI ID:
- 6049489
- Journal Information:
- J. Heat Transfer; (United States), Journal Name: J. Heat Transfer; (United States) Vol. 101:1; ISSN JHTRA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
141000* -- Solar Collectors & Concentrators
ANNULAR SPACE
CONFIGURATION
CONVECTION
ENERGY LOSSES
ENERGY TRANSFER
EVACUATED COLLECTORS
EVACUATED TUBE COLLECTORS
HEAT LOSSES
HEAT TRANSFER
HIGH TEMPERATURE
LOSSES
LOW PRESSURE
MEDIUM PRESSURE
MEDIUM TEMPERATURE
MEDIUM VACUUM
NATURAL CONVECTION
PRESSURE DEPENDENCE
SOLAR COLLECTORS
TEMPERATURE DISTRIBUTION
THERMAL CONDUCTION