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Title: Analytical model of an irrigated packed-bed direct-contact heat exchanger at high temperature

This paper presents an analytical model of direct-contact heat exchange (DCHX) in an irrigated packed bed at high temperatures. The specific application is heat exchange between molten salt and air where the molten salt is a sensible heat storage medium and high temperature air is required for an end process. The model defines several heat transfer mechanisms between the three components in the bed - the liquid, the gas, and the packing. It also includes the effect of conduction in the packing. Correlations found in the literature are used to calculate the associated heat transfer coefficients. The model is restricted to liquids that wet the packing material and to gas/liquid flow rates below the loading point. Three dimensionless equations describe the heat balance between the three bed components. The resulting dimensionless parameters reveal that for commercial DCHX systems, radiation heat transfer is unimportant relative to the convective heat transfer, which is consistent with previous experimental results for air/mercury and nitrogen/molten lead systems. The model also predicts volumetric heat transfer coefficients of about 10,000 W/m/sup 3/K, which is consistent with experimental work.
Authors:
Publication Date:
OSTI Identifier:
7058886
Report Number(s):
SERI/TP-252-2976; CONF-870307-17
ON: DE87001119
DOE Contract Number:
AC02-83CH10093
Resource Type:
Conference
Resource Relation:
Conference: ASME/JSME/ISES solar energy conference, Honolulu, HI, USA, 22 Mar 1987; Other Information: Portions of this document are illegible in microfiche products
Research Org:
Solar Energy Research Inst., Golden, CO (USA)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; DIRECT CONTACT HEAT EXCHANGERS; MATHEMATICAL MODELS; THREE-DIMENSIONAL CALCULATIONS; HEAT TRANSFER; HIGH TEMPERATURE; MOLTEN SALTS; ENERGY TRANSFER; HEAT EXCHANGERS; SALTS SOLAR THERMAL CENTRAL RECEIVER; MOLTEN SALT; HEAT TRANSFER; PACKED BED 140700* -- Solar Thermal Power Systems