Natural convection and sidewall losses in trapezoidal groove collectors

Journal Article · Fri May 01 04:00:00 EDT 1981 · J. Sol. Energy Eng.; (United States)

DOI:https://doi.org/10.1115/1.3266223· OSTI ID:5747303

Iyican, L ^[1]; Witte, L C ^[2]; Bayazitoglu, Y ^[3]

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1. Shell Development Co., Houston, TX
2. Univ. of Houston, TX
3. Rice Univ., Houston, TX

Experimental data for heat transfer across air-filled inclined trapezoidal enclosures are reported for a Rayleigh number range of approximately 2 x 10 to the 3rd to approximately 5 x 10 to the 7th. The large side was cooled to uniform temperature while the opposing small side was electrically heated. The enclosures were completed by two aluminum sidewalls which simulated the reflective surfaces in moderately-concentrating solar collectors. The experiments show that conductive heat losses up the sidewalls can be very large even when the sidewalls are thermally insulated from the top and bottom surfaces. However, the conductivity of the sidewalls has only a small effect on convective heat transfer across the groove. Natural convection heat transfer in the groove can be correlated reasonably well by an equation of the form Nu C Ra exp 0.345.

• OSTI ID: 5747303
• Journal Information: J. Sol. Energy Eng.; (United States), Journal Name: J. Sol. Energy Eng.; (United States) Vol. 103; ISSN JSEED
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
141000* -- Solar Collectors & Concentrators
CONVECTION
ENERGY LOSSES
ENERGY TRANSFER
EQUIPMENT
HEAT LOSSES
HEAT TRANSFER
LOSSES
NATURAL CONVECTION
NUSSELT NUMBER
PHYSICAL PROPERTIES
SOLAR COLLECTORS
SOLAR EQUIPMENT
TEMPERATURE DISTRIBUTION
THERMAL CONDUCTION
THERMAL CONDUCTIVITY
THERMAL INSULATION
THERMODYNAMIC PROPERTIES