Effects of Vaporizer and Evaporative Condenser Pinch Points on Geofluid Effectiveness and Cost of Electricity for Geothermal Binary Power Plants

摘要

A brief study was conducted in support of the DOE/DGHT Heat Cycle Research Program to investigate the influences of minimum approach temperature differences occurring in supercritical-heater/vaporizer and evaporative-condenser heat rejection systems on geothermal-electric binary power plant performance and cost of electricity. For the systems investigated optimum pinch points for minimizing cost of electricity were estimated to range from 5 to 7 exp 0 F (3 to 4 exp 0 C) for the heater vaporizer. The minimum approach of condensing temperature to wet-bulb temperature for evaporative condensers was estimated to be about 15 exp 0 F (8 exp 0 C) in order to achieve the highest plant net geofluid effectiveness, and approximately 30 exp 0 F (17 exp 0 C) to attain the minimum cost of electricity. (ERA citation 09:047685)