STG-8 Analysis of Data from Brine - Hydrocarbon Heat Exchangers Used in the Heber Geothermal Binary Power Plant

A. Salehpour, K. Ishihara, and J. Herringer

This paper discusses the analysis of heat exchanger data from a commercial-size geothermal binary power plant. The data are from a train of four NTIW (No-Tube-in-the-Window), F-shell exchangers in series. The heating medium is hot brine which flows in the tube side of the exchangers. The shellside fluid is a mixture of isobutane and isopentane. The shellside fluid condition changes from subcritical to supercritical as it passes through the train. The thermophysical properties of the hydrocarbon change drastically with the temperature near the critical region. The data have been analyzed using the Heat Transfer Research, Inc. (HTRI) ST Computer Program. The analysis has shown that the effect of the nonlinearity of the properties has to be taken into account by designing the exchangers through a stepwise procedure.