This study aims to optimize biogas production at the laboratory scale using a batch-mode bioreactor and Response Surface Methodology (RSM). The main objective is to assess the effects of key parameters substrate composition (household waste and cow manure), pH, fermentation temperature, and agitation speed on biogas yield.series of experiments were designed using a central composite RSM to evaluate the influence of substrate composition and temperature. The experimental data were analyzed through ANOVA to assess model significance and accuracy.The results show that the developed quadratic models are statistically significant, with a determination coefficient (R²) of 0.90 for cumulative biogas production. These findings confirm the adequacy of the models and the effectiveness of RSM in identifying optimal operating conditions for enhanced biogas yield.

The unpredictable nature of energy markets makes precise electricity price forecasting (EPF) necessary to improve bidding strategies and lower risk. For instance, this study introduces a hybrid deep learning model CNN-GRU-VAE, that learns sequences using Gated Recurrent Units (GRU), finds features using Convolutional Neural Networks (CNN), and becomes more general using a Variational Autoencoder (VAE). In tests that looked ahead one day, the CNN-GRU-VAE performed better than the CNN, ANN, GRU, and CNN-GRU models. The model’s Root Mean Squared Error (RMSE) is 0.8733, Mean Squared Error (MSE) is 0.7627, and Mean Absolute Error (MAE) is 0.6373. These findings demonstrate improved accuracy and stability across diverse market conditions. The integration of convolutional, recurrent, and generative components within a unified framework provides superior predictions compared to traditional methods, demonstrating robustness and practical applicability for day-ahead electricity price forecasting in competitive energy markets.

In many places, including Iraq, wind energy is a cheap, sustainable resource that is also environmentally benign. Despite its substantial wind potential, Iraq continues to experience an energy deficit due to the underutilization of renewable resources. To close this gap, this study will use a multi-criteria evaluation (MCE) technique in a Geographic Information System (GIS) context to determine the best places for wind energy development in Iraq. The assessment considers several geographic elements that affect wind farm placement, such as wind speed, land slope, distance from water bodies, and proximity to power lines and key roadways. A final suitability map that highlighted locations with differing degrees of acceptability for wind energy harvesting was created by integrating these parameters. According to the results, about 31% of the research region is highly favorable to wind farms, 30% is somewhat reasonable, and 39% is unsuitable. The southern and portions of central Iraq were the most promising regions for wind energy development. These results provide a sound scientific foundation for strategic planning and investment in sustainable energy infrastructure by energy planners and decision-makers. The study helps Iraq meet its sustainable development objectives, lessen its dependency on fossil fuels, and lessen its environmental effects.

The main challenge in the development of the oil and gas industry is the reduction in hydrocarbon production using traditional methods due to the increasing share of hard-to-reach oil and gas reserves in the production structure and the insufficiency and practical unfeasibility of innovative resource-efficient methods and techniques for enhancing oil productivity from heterogeneous reservoirs. The objective of this study is to develop a new hydromechanical perforation technique for enhancing oil well productivity from heterogeneous reservoirs of oil and gas fields using an innovative method called "tunnel perforation". The application of the new approach to stimulating heterogeneous reservoirs allows for a significant increase in oil production without the use of explosives. Within a single tripping operation, three technological processes are conducted simultaneously: perforation (primary and secondary), destruction of the cement sheath behind the casing, and acid treatment of the near-wellbore zone. After the completion of the acid treatment, using the initial set of downhole tools, the products of chemical reactions are extracted to the surface without associated material components. The use of tunnel perforation technology allows for effective oil and gas production for subsurface users within a single tripping operation, compared to existing technologies such as cumulative perforation. The system was implemented and tested in three oil fields in different countries, namely, Group of reservoirs A, Group of reservoirs Ach, and Group of reservoirs B. The field test results showed an increase in the reservoir's productivity by 319% for group A, 120.2% for group Ach, and 114.8% for group B.

Flat plate solar collectors are widely employed in applications operating at low to moderate temperatures, including domestic water heating and various industrial uses. Their thermal performance is strongly influenced by the absorber tube, through which solar energy is transmitted to the circulating fluid. Conventional designs are often limited by low convective heat transfer, which has motivated studies on geometric enhancements to improve overall efficiency. The present work examines the thermo-hydraulic characteristics of a flat plate solar air collector fitted with twisted tape inserts having various twist ratios ($\delta$ = 3, 4, 5, 6), and compares the results with a plain tube collector. Air serves as the working fluid, and simulations were carried out over a Reynolds number range of 200–2000. A three-dimensional CFD approach was employed to study critical performance characteristics, including outlet temperature, Nusselt number, friction factor, pumping power, and thermal efficiency. The results show that twisted tape collector (TTC) provide considerably greater heat transfer compared to the plain collector (PC). At Re = 1000, the Nusselt number enhancement reached 35.19%, 44.55%, 50.15%, and 54.96% for twist ratios $\delta$ = 6, 5, 4, and 3, respectively. Although this improvement is associated with increased pressure drops, the findings confirm that twisted tape inserts substantially enhance the heat transfer effectiveness of solar collectors by promoting turbulence and better fluid mixing.

While solar still technology offers a sustainable solution to freshwater scarcity, its practical application is often limited by low productivity. This study aims to enhance the water production of a double-slope solar still through the simultaneous implementation of a glass cover cooling mechanism and a flat-plate solar collector. Three configurations were experimentally compared: a conventional solar still (SSC), a solar still with cover cooling (SST1), and a solar still integrating both cover cooling and a solar collector (SST2). Experimental results show that SST2 achieved lower glass cover temperatures than the SSC and higher water temperatures than the SST1, thereby accelerating both evaporation and condensation rates. Quantitatively, the SST2 configuration yielded a freshwater productivity of 2092 g/m², a significant increase of 147% compared to the SSC. Furthermore, its energy efficiency reached 44.53%, in contrast to 27.38% for SSC and 27.27% for SST1. Economically, SST2 demonstrated the lowest freshwater production cost at $0.082/(L·m²). These findings rigorously prove that the simultaneous use of cover cooling and a solar collector is a highly effective strategy for increasing the productivity and improving the economic viability of solar stills.

In a global context where buildings account for approximately 30% of final energy demand and 26% of energy-related greenhouse gas emissions, improving the building envelope is a key strategy for achieving sustainability goals. This study investigates the energy, environmental and visual performance of a dynamic Second Skin Fac¸ade (SSF) system applied as a passive retrofit solution for a typical office building located in Trondheim, Norway. The SSF integrates adaptive technologies and is composed of 3D-printed panels in Acrylonitrile Styrene Acrylate (ASA): solid panels for opaque walls and perforated panels for windows. A simulation-based methodology using TRNSYSsoftware was implemented to compare the performance of the retrofitted building against a reference case. Additionally, a gate-to-gate Life Cycle Assessment was performed to assess the environmental impact of the 3D-printed components. Results highlight a reduction in primary energy demand by up to 25.5% and an annual decrease of approximately 1.4 tCO_2eq, particularly when the dynamic shading control is based on vertical solar radiation. Although the Global Warming Potential of ASA panels is higher than that of conventional materials, the local production and Norway’s low-carbon electricity grid contribute to a favorable environmental profile. The f indings underline the potential of 3D printing for adaptive envelope solutions.

This research is devoted to the electromechanical properties of axle mount devices with piezoelectric elements and their performance under various loading conditions. It performs a complex computational simulation of the interaction between mechanical energy and electrical generation. In the study, the research team examined the technical aspects and scale-up issues of integrating piezoelectric energy harvesting networks into conventional roads. The function of piezoelectric material in car wheels, which senses patient head movement and stability via pressure, is covered in the study. Important considerations include the material’s size, voltage, and Deformation. The extracted materials’ power frequency ranges from 62 Hz to 80 Hz, with 80 Hz used for mechanical energy extraction. The COMSOL 6.3 Multiphysics program was used as a simulation program. The research studies the association of piezoelectric materials, as well as power car tires, concentrating on their mechanics, electronic components, and thermal properties. The study shows that the pulse electric value is proportional to material thickness, voltage, and strain. Being a function of strain and electric power, the electromotive force, mechanical power, and electric power also change with increasing frequency. The temperature dynamics of piezoelectric mechanisms rely heavily on the resistance of the material, which results in a temperature rise that, in turn, produces an input voltage and electron movement. The 1e9 ohm resistance is the best choice, as it provides increased current flow and an electrical potential of 0.7 volts.