This study focused on exergo–conomic and parametric analysis for Taji station in Baghdad. This station was chosen to reduce the emission of waste gases that pollute the environment, as it is located in a residential area, and to increase the production of electric power, since for a long time, Iraq has been a country that has suffered from a shortage of electricity. The main objective of this work is to integrate the Taji gas turbine’s power plant, which is in Baghdad, with the Rankine cycle and organic Rankine cycle to verify waste heat recovery to produce extra electricity and reduce emissions into the environment. Thermodynamic and exergoeconomic assessment of the combined Brayton cycle–Rankine cycle/Organic Rankin cycle (GSO CC) system, considering the three objective functions of the First- and Second-Law efficiencies and the total cost rates of the system, were applied. According to the findings, 258.2 MW of power is produced from the GSO CC system, whereas 167.3 MW of power is created for the Brayton cycle (BC) under the optimum operating conditions. It was demonstrated that the overall energy and exergy efficiencies, respectively, are 44.37% and 42.84% for the GSO CC system, while they are 28.74% and 27.75%, respectively, for the Brayton cycle. The findings indicate that the combustion chamber has the highest exergy degradation rate. The exergo–economic factor for the entire cycle is 37%, demonstrating that the cost of exergy destruction exceeds the cost of capital investment. Moreover, the cost of the energy produced by the GSO CC system is USD 9.03/MWh, whereas it is USD 8.24/MWh for BC. The results also indicate that the network of the GSO CC system decreases as the pressure ratio increases. Nonetheless, the GSO CC system’s efficiencies and costs increase with a rise in the pressure ratio until they reach a maximum and then decrease with further pressure ratio increases. The increase in the gas turbine inlet temperature and isentropic efficiency of the air compressor and gas turbine enhances the thermodynamic performance of the system; however, a further increase in these parameters increases the overall cost rates.

Enhancing the sustainability and diversification of Iraq’s electricity system is a strategic objective. Achieving this goal depends critically on increasing the use of renewable energy sources (RESs). The significance of developing solar-powered technologies becomes essential at this point. Iraq, similar to other places with high average direct normal irradiation, is a good location for concentrated solar thermal power (CSP) technology. This study aims to recover the waste heat from the gas turbine cycle (GTC) in the Al-Qayara power plant in Iraq and integrate it with a solar power tower. A thermoeconomic analysis has been done to support the installation of an integrated solar combined cycle (ISCC), which uses concentrated solar tower technology. The results indicate that the examined power plant has a total capacity of 561.5 MW, of which 130.4 MW is due to the waste heat recovery of G.T.s, and 68 MW. is from CSP. Due to the waste heat recovery of GTC, the thermal and exergy efficiencies increase by 10.99 and 10.61%, respectively, and the overall unit cost of production is 11.43 USD/MWh. For ISCC, the thermal and exergy efficiencies increase by 17.96 and 17.34%, respectively, and the overall unit cost of production is 12.39 USD/MWh. The integrated solar combined cycle’s lowest monthly capacity was about 539 MW in September, while its highest monthly capacity was approximately 574.6 MW in April.

The heat exchanger is crucial to all systems and applications that use it. Researchers are primarily focused on improving this component’s thermal conductivity to improve its efficiency. This was achieved by using one or more of the following strategies: inserting tapes with various shapes and numbers, inserting rings of various shapes and spacing between each, and transforming a basic liquid into a nanoliquid by adding nanomaterials with high conductivity and ultra-small particle sizes. Different types of nanomaterials were added in varying concentrations. In earlier studies, it was found that every increase in heat transfer was accompanied by a pressure drop at both ends of the exchanger. The amount of heat transferred and the pressure drop are affected by many factors, such as the torsion tape ratio, the pitch of the ring, and whether the pitch faces the direction of flow or not. Heat transfer rates can also be impacted by factors such as the length and angle of the wings, how many rings and tapes there are, and whether the rings and tapes contain holes or wings. In addition, the Reynolds number, the type, conductivity, and size of nanomaterials, and the base fluid used in the nanofluid affect this. It is possible for the shape of the exchanger tube, as well as varying rates of rise, to introduce such impacts. In this study, the factors, costs, and benefits of using any technology to increase the efficiency of the heat exchanger are reviewed so that the user can make an informed decision about the technology to use.

This study aims to develop, evaluate, and improve a polygeneration system that combines solar and Brayton cycle technologies and focuses on the sequential integration of heat. In this configuration, the exhaust gases from the Al-Qayyarah gas turbine power plant and the parabolic trough collector (PTC) array generate steam through a high recovery steam generation process. An absorption refrigeration system also supplies the Brayton circuit with low-temperature air. This process is evaluated from a 3E perspective, which includes exergy, energy, and exergoeconomic analyses for two different configurations. These configurations are integrated solar combined cycle (ISCC) with and without absorption systems (ISCC and ISCC-ARC). In addition, a comprehensive analysis was carried out to assess the impact of critical factors on the output generated, the unit cost of the products, and the exergy and energy efficiency for each configuration. The results revealed that the power produced by the ISCC-ARC and ISCC systems is 580.6 MW and 547.4 MW, respectively. Accordingly, the total energy and exergy efficiencies for the ISCC-ARC are 51.15% and 49.4%, respectively, while for the ISCC system, they are 50.89% and 49.14%, respectively. According to the results, the total specific costs for the ISCC-ARC system increased from 69.09 $/MWh in June to 79.05 $/MWh in December. ISCC’s total specific costs also fluctuate throughout the year, from 72.56 $/MWh in June to 78.73 $/MWh in December.

In this study, it is proposed to generate electrical energy by recovering the waste heat of an annealing furnace (AF) in an iron and steel plant using combined cycles such as steam Rankine cycle (SRC), organic Rankine cycle (ORC), Kalina cycle (KC) and transcritical CO₂ cycle (t-CO₂). Instead of releasing the waste heat into the atmosphere, the waste heat recovery system (WHRS) discharges the waste heat into the plant’s low-temperature oxygen line for the first time, achieving a lower temperature and pressure in the condenser than conventional systems. The waste heat of the flue gas (FG) with a temperature of 1093.15 K from the reheat furnace was evaluated using four different cycles. To maximize power generation, the SRC input temperature of the proposed system was studied parametrically. The cycles were analyzed based on thermal efficiency and net output power. The difference in SRC inlet temperature is 221.6 K for maximum power output. The proposed system currently has a thermal efficiency and total power output of 0.19 and 596.6 kW, respectively. As an environmental impact, an emission reduction potential of 23.16 tons/day was achieved. In addition, the minimum power generation cost of the proposed system is $0.1972 per kWh.