On-design pre-optimization and off-design analysis of hybrid Brayton thermosolar tower power plants for different fluids and plant configurations
[EN]A working fluid performs a Brayton cycle that is fed by a heat input from a solar power tower and from a combustion chamber, which burns natural gas. This hybrid system is described by a complete model that includes all the main losses and irreversibility sources (optical and thermodynamic). Num...
| Autores: | , , , , , |
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| Formato: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2020 |
| País: | España |
| Recursos: | Universidad de Salamanca (USAL) |
| Repositorio: | GREDOS. Repositorio Institucional de la Universidad de Salamanca |
| OAI Identifier: | oai:gredos.usal.es:10366/141171 |
| Acesso em linha: | http://hdl.handle.net/10366/141171 |
| Access Level: | acceso abierto |
| Palavra-chave: | Thermosolar hybrid plants Multi-stage Brayton On-design pre-optimization Off-design analysis Greenhouse emissions 2213 Termodinámica |
| Resumo: | [EN]A working fluid performs a Brayton cycle that is fed by a heat input from a solar power tower and from a combustion chamber, which burns natural gas. This hybrid system is described by a complete model that includes all the main losses and irreversibility sources (optical and thermodynamic). Numerical implementation and validation is performed based on a Spanish commercial plant. On-design computations are carried out varying the pressure ratio for four working fluids (dry air, nitrogen, carbon dioxide, and helium), for different number of stages and for recuperative and non-recuperative configurations. When adjusting the pressure ratio, an improvement of about 7% in overall thermal efficiency is predicted for a dry air single-stage recuperative configuration with respect to a standard commercial gas turbine. A study about the main energy losses in each plant subsystem for some particular plant layouts is accomplished. A two-compression and expansion stages recuperative Brayton cycle working with air is expected to give overall thermal efficiencies about 0.29 at design conditions, which is about a 47% increase with respect to the simplest single-stage configuration. It is stressing that fuel consumption from the reheaters maybe higher than that of the main combustion chamber for multi-stage layouts. Off-design hourly curves of output records for the four seasons throughout a day are analyzed. Greenhouse emissions are also analyzed. Specific carbon dioxide emissions are smaller for helium than for dry air, when they both work in a single-stage non-recuperative configuration |
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