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Title: Thermal performance of a geofluid direct-contact heat exchanger

Conference ·
OSTI ID:6457851

A sieve-tray direct-contact heat exchanger was used to transfer heat from a 280/sup 0/F geothermal fluid to the working fluid, isobutane, in the Raft River 60kW prototype plant. A series of experiments were run at different working fluid-to-geofluid flow ratios which produced different boiling conditions. In this paper, the results of these experiments are analyzed on the basis of thermal performance. The flow ratio, the geofluid outlet temperature, the working fluid inlet temperature, the amount of working fluid dissolved or entrained in geofluid, and tray efficiency are varied and preheating temperature profiles are calculated. These are compared with the experimentally obtained temperature profiles and the relative effects of the variables are evaluated. From this, it was determined that the approach temperature difference was on the order of .1/sup 0/ after 17 preheating trays, and the tray efficiencies, which appear to be about the same for all trays, reached approx. 70%. It was also determined that entrainment has a negligible effect on column thermal performance. The thermal performance of this column compares favorably with a spray-tower direct-contact heat exchanger and a shell-and-tube heat exchanger in terms of overall heat-transfer coefficient. Distributor tray and boiling tray behavior are discussed. These is some discussion of operations and thermal hydraulics as well.

Research Organization:
EG and G Idaho, Inc., Idaho Falls (USA)
DOE Contract Number:
AC07-76ID01570
OSTI ID:
6457851
Report Number(s):
EGG-M-23982; CONF-830301-15; ON: DE82013233
Resource Relation:
Conference: ASME-JSME thermal engineering joint conference, Honolulu, HI, USA, 20 Mar 1983
Country of Publication:
United States
Language:
English