Transient natural convection in enclosures with application to solar thermal storage tanks

Journal Article · Sat Aug 01 04:00:00 EDT 1992 · Journal of Solar Energy Engineering; (United States)

DOI:https://doi.org/10.1115/1.2930002· OSTI ID:6991546

Reindl, D T; Beckman, W A; Mitchell, J W ^[1]

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1. Wisconsin Univ., Madison, WI (United States). Solar Energy Lab.

Many previously studied natural convection enclosure problems in the literature have the bounding walls of the enclosure responsible for driving the flow. A number of relevant applications contains sources within the enclosure which drive the fluid flow and heat transfer. The motivation for this work is found in solar thermal storage tanks with immersed coil heat exchangers. The heat exchangers provide a means to charge and discharge the thermal energy in the tank. The enclosure is cylindrical and well insulated. Initially the interior fluid is isothermal and quiescent. At time zero, a step change in the source temperature begins to influence the flow. The final condition is a quiescent isothermal fluid field at the source temperature. The governing time-dependent Navier-Stokes and energy equations for this configuration are solved by a finite element method. Solutions are obtained for 10[sup 3] [le] Ra[sub D] [le] 10[sup 6]. Scale analysis is used to obtain time duration estimates of three distinct heat transfer regimes. The transient heat transfer during these regimes are compared with limiting cases. In this paper correlations are presented for the three regimes.

• OSTI ID: 6991546
• Journal Information: Journal of Solar Energy Engineering; (United States), Journal Name: Journal of Solar Energy Engineering; (United States) Vol. 114:3; ISSN JSEEDO; ISSN 0199-6231
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
141000 -- Solar Collectors & Concentrators
142000* -- Solar Energy-- Heat Storage-- (1980-)
25 ENERGY STORAGE
250600 -- Energy Storage-- Thermal
42 ENGINEERING
420400 -- Engineering-- Heat Transfer & Fluid Flow
CONTAINERS
CONVECTION
CONVERSION
DIFFERENTIAL EQUATIONS
ENERGY
ENERGY CONVERSION
ENERGY SOURCES
ENERGY STORAGE
ENERGY TRANSFER
EQUATIONS
EQUIPMENT
FINITE ELEMENT METHOD
HEAT EXCHANGERS
HEAT STORAGE
HEAT TRANSFER
ISOTHERMAL PROCESSES
MASS TRANSFER
NATURAL CONVECTION
NAVIER-STOKES EQUATIONS
NUMERICAL SOLUTION
PARTIAL DIFFERENTIAL EQUATIONS
RENEWABLE ENERGY SOURCES
SEASONAL THERMAL ENERGY STORAGE
SOLAR COLLECTORS
SOLAR ENERGY
SOLAR ENERGY CONVERSION
SOLAR EQUIPMENT
SOLAR THERMAL CONVERSION
STORAGE
TANKS
THERMAL ENERGY STORAGE EQUIPMENT
TRANSIENTS