Author: A.E. Bergles

Publisher:

Published: 1977

Total Pages: 0

ISBN-13:

Preliminary studies have shown that the heat exchanger costs for an. Ocean Thermal Energy Conversion (OTEC) system represent approximately one half of the total capital cost. Much of the OTEC research is now directed at development of lower cost heat exchangers which are not unduly affected by biofouling. It appears that reduced size (and cost) will require utilization of enhanced heat transfer surfaces for both the boiler and the condenser. This paper reports on. an initial study directed toward assessing the potential for heat transfer enhancement of the sea water, or single-phase side, of these heat exchangers. Single-phase, forced convection heat transfer can be enhanced by a wide variety of techniques, Of primary interest in large-scale heat ex-'change equipment are a number of "passive" techniques which do not require external power to generate and sustain the improvement. These techniques are:. rough surfaces, extended surfaces, displaced enhancement devices, and swirl flow devices. As part of thin study the world literature was surveyed to locate representative data for these techniques. A computer search of an extensive collection of general literature on heat transfer enhancement was utilized. Heat transfer and friction factor data are presented for various techniques and subgroups of techniques, particularly those data which demonstrate the maximum reported improvements in heat transfer coefficients. The enhancement data are screened using a performance evaluation criterion which represents a measure of the reduction in heat transfer surface area with enhancement, subject to the constraints of constant.