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Research on the heat exchangers for the co-generating units was carried out to obtain the best design, by comparing the efficiency and the concepts used by different heat exchangers. The system was designed based on three basic parameters optimization: number of coolant tubes, diameter of the coolant tube and inlet velocity of the cold gases. These three variables were manipulated in order to investigate heat transfer performances, as well as, effects of heat transfer fluids and the system’s efficiency. Simulations using Computational Fluid Dynamic (CFD) were carried out, to have a better understanding and distinct visualization of the fluid flow, and to test and compare the results. The outcomes show that, different size of coolant tube diameter has the biggest impact on the system efficiency, compared to the other two variables. Design improvement, based on the contributions of the key parameters to efficiency of the heat exchanger, is recommended, as a final outcome of the project conducted. [ABSTRACT FROM AUTHOR]

• The coupling of CCPP power generation units to an inlet air cooling system has been presented. • Classifications and performance of the inlet air cooling systems have been reviewed. • Technical characteristics of various inlet air cooling techniques on the CCPP have been compared. • The thermal performance of the inlet air cooling technique and its effect on the CCPP performance augmentation has been reviewed. This work aims to provide a state-of-the-art review of the performance of combined cycle power plant (CCPP) based on several proposed inlet air cooling systems. Investigators strive to meet the significant need to promote and develop inlet air cooling technologies to recover heat from the wasted energy in the exhaust gasses of the CCPP and diminish the environmental impacts. Various types of cooling systems mainly offer a boost for electric power generation during the peak load hours. The output power of the CCPP directly depends on the mass flow rate of air that flows through the air compressor. Therefore, during extremely hot weather conditions, subsequently, the air density drops, and this leads to a drastic decrease in the power output. This paper reviews available studies investigated the impacts of inlet air cooling systems on the performance of the CCPP. The fogging cooling system contributed by up to 17% in improving the total performance of the CCPP; however, with the use of the evaporative cooling, the performance was enhanced by only 4%. The energy consumption of mechanical chiller compared to that of evaporative cooling is high due to the effectiveness of the evaporative cooler which depends on the humidity of inlet airflow. Further, the mechanical cooling system can provide the CCPP with a cooling effect for around 7-hour on-peak periods. This method increases the gain of the CCPP performance by 13.6%. Ultimately, the CCPP equipped with an absorption chiller demonstrates the best solution to increase the performance by up to 23%. [ABSTRACT FROM AUTHOR]

• Novel hybrid rainfall hydropower with solar photovoltaic-battery is introduced. • Photovoltaic-battery and photovoltaic-battery-hydro system are analysed and compared. • Robust energy management is carried out to utilize the excess power for water pumping. • Photovoltaic-battery-hydro and robust energy management reduces levelized cost of energy. • The hybrid photovoltaic-battery-hydro is suiting standalone rural electrification. This paper presents analysis and optimization of standalone hybrid renewable energy system for powering a 3.032 kWh/day housing unit. The hybrid system is strategized to utilize harvesting rainfall and integrating a pumped-hydro storage with a solar photovoltaic-battery system. The optimization, using particle swarm optimization technique, is conceived for minimizing the over sizing of components and secure reliable power supply management with objective function to minimize the levelized cost of energy for loss of power supply probability of 0.0. Four different cases have been optimized, analyzed and compared. Case 1 is a conventional photovoltaic-battery system, Case 2 is photovoltaic-battery integrated with hydro system utilizing only the direct rainfall, Case 3 is photovoltaic-battery integrated with pumped-hydro storage system with the battery bank as the primary power backup, and Case 4 is the photovoltaic-battery integrated with pumped-hydro storage system with hydro system as the primary power backup. Results are revealing that integration of rainfall-based hydropower system of only 100 W with effective water storage of 6.5 m3 at 7.0 m of net water head has resulted in reduction of the installed photovoltaic capacity by about 13.0% compared to power system without rainfall-based hydropower system. The highest hydropower share of 5.0% is observed in Case 4. Case 4 has also resulted in least levelized cost of energy of 0.443 $/kWh. It has been demonstrated that it is possible to achieve environmental appropriateness, reliable and low-cost power generation by integration of harvesting rainfall with photovoltaic-battery system. The suggested system has less dependency on the battery storage as the batteries are the most expensive part with short life span in the proposed integrated renewable systems. [ABSTRACT FROM AUTHOR]