Abstract

This research presents an exergy analysis of a gas turbine power plant situated in Assiut, Egypt, operating under high-temperature conditions. The aim of the study is to assess the performance of the simple gas turbine cycle and identify the sources of thermodynamic inefficiencies using the second law of thermodynamics as a basis for analysis. To accomplish this, a model was developed in EES software utilizing real operational data obtained from the plant's control system. The investigation focused on the impact of varying ambient temperature on the exergy efficiency, exergy destruction, and net power output of the cycle. The results revealed that the combustion chamber accounted for the highest exergy destruction, amounting to 85.22%. This was followed by the compressor at 8.42% and the turbine at 6.36%. The overall energy and exergy efficiencies of the system were determined to be 28.8% and 27.17%, respectively. Furthermore, the study examined the effects of increasing ambient temperature from 0 to 45°C on the system's performance. It was observed that as the temperature rose, the overall exergy efficiency decreased from 27.91 to 26.63%. Simultaneously, the total exergy destruction increased from 126,407 to 138,135 kW. Additionally, the net power output exhibited a decline from 88,084 to 84,051 kW across the same ambient temperature range. These findings highlight the significant influence of ambient temperature on the thermodynamic performance of gas turbine power plants. As temperature rises, a greater amount of exergy is lost, resulting in reduced efficiency and diminished net power output. Therefore, optimizing the design of the combustion chamber is crucial for mitigating the adverse effects of hot weather conditions. The insights obtained from this study can be utilized to enhance the design and operation of gas turbine plants operating in hot climates.

Abstract

This study evaluates the recent investigations and economic assessments on using the solar-driven organic Rankine cycle (ORC) as a power source for membrane-based desalination systems, specifically reverse osmosis (RO) systems. Several numerical and experimental studies from the last decade on the design and performance of RO-ORC desalination systems have comprehensively been reviewed. This intensive study aims to critically review RO-ORC systems and update on the recent advancements in systems performance, design, and characteristics. It also focuses on the main challenges, limitations, improvements, and techno-economic factors affecting RO-ORC performance. Four categories were used to group the investigations: the RO desalination process, the Organic Rankine cycle (ORC), the solar ORC-powered RO desalination, and economic assessment criteria. RO-ORC performance is affected by the system design parameters, RO unit characteristics, feed water qualities, climatic conditions, and the ORC process’s working fluid. The assessment focuses on recovery ratios, water quality, system efficiency, system, and plant design and the SEC as performance evaluation measures. The literature review declared that improved membrane materials and module designs have reduced energy usage because of the continual process improvements and cost savings. These advances cut membrane costs per unit of water produced in half. In addition, many modern technology combinations have been studied and used to boost efficiency and reduce energy needs in reverse osmosis plants. Using solar-driven ORC-RO has shown promising results in places with ample solar resources or low-grade thermal energy. Many conclusions and expected remaining challenges are highlighted in the study.