A thermodynamic analysis was performed in order to study the possibility of upgrading the thermodynamic performance of a direct-steam geothermal power plant through the use of a separating expander which produces work while achieving effective separation of the two phases. One such device is the Biphase rotary separator. Preliminary testing of this device demonstrated that the isentropic efficiency is about 34% and that the separation efficiency is greater than 99.5%. The analysis indicates that separating expanders can provide a marked thermodynamic improvement over the flash tank arrangement. The analysis shows that even with relatively inefficient separators similar to the prototype tested an improvement of 18 to 21% is possible depending on the initial temperature of the liquid (the improvement is greater for low initial temperature). If the efficiency of the separating expanders can be upgraded from 30% to 50%, single stage systems can produce from 35% (T/sub i/ = 250°C) to 52% (T/sub l/ = 150°C) more work than the equivalent single-flash systems. On the other hand, with the same level of expander efficiency, the two-stage system reflects a 26% advantage over the equivalent dual-flash system. It should be noted, however, that the optimum intermediate temperatures exhibit a pronounced dependence on the efficiency of the expanders. It is also noted that the Biphase device is not the only one that can achieve separation of the phases while producing work. The same functions may be performed by a combination of a total flow expander and a conventional separator. (JGB).

Thermodynamic Analysis and Optimization of Geothermal Power Plants guides researchers and engineers on the analysis and optimization of geothermal power plants through conventional and innovative methods. Coverage encompasses the fundamentals, thermodynamic analysis, and optimization of geothermal power plants. Advanced thermodynamic analysis tools such as exergy analysis, thermoeconomic analysis, and several thermodynamic optimization methods are covered in depth for different configurations of geothermal power plants through case studies. Interdisciplinary research with relevant economic and environmental dimensions are addressed in many of the studies. Multiobjective optimization studies aimed at better efficiency, lower cost, and a lower environmental impact are also discussed in this book. Addresses the complexities of thermodynamic assessment in almost all operational plant configurations, including solar-geothermal and multigeneration power plants Includes an exemplary range of case studies, from basic to integrated Provides modern optimization methods including exergoeconomic, artificial neural networks, and multiobjective particle swarm Covers environmental impact considerations and integration with renewable energy systems

Comprehensively covers geothermal energy systems that utilize ground energy in conjunction with heat pumps to provide sustainable heating and cooling The book describes geothermal energy systems that utilize ground energy in conjunction with heat pumps and related technologies to provide heating and cooling. Also discussed are methods to model and assess such systems, as well as means to determine potential environmental impacts of geothermal energy systems and their thermal interaction. The book presents the most up-to-date information in the area. It provides material on a range of topics, from thermodynamic concepts to more advanced discussions of the renewability and sustainability of geothermal energy systems. Numerous applications of such systems are also provided. Geothermal Energy: Sustainable Heating and Cooling Using the Ground takes a research orientated approach to provide coverage of the state of the art and emerging trends, and includes numerous illustrative examples and case studies. Theory and analysis are emphasized throughout, with detailed descriptions of models available for vertical and horizontal geothermal heat exchangers. Key features: Explains geothermal energy systems that utilize ground energy in conjunction with heat pumps to provide heating and cooling, as well as related technologies such as thermal energy storage. Describes and discusses methods to model and analyze geothermal energy systems, and to determine their potential environmental impacts and thermal interactions. Covers various applications of geothermal energy systems. Takes a research orientated approach to provide coverage of the state of the art and emerging trends. Includes numerous illustrative examples and case studies. The book is key for researchers and practitioners working in geothermal energy, as well as graduate and advanced undergraduate students in departments of mechanical, civil, chemical, energy, environmental, process and industrial engineering.