The Photovoltaic Thermal (PV/T) system, capable of simultaneously generating electricity and thermal energy, provides an alternative and efficient approach to conventional solar water heater (SWH) systems. Although numerous reviews on PV/T technology exist, they often operate in isolation, concentrating either on thermal performance, electrical efficiency, or a simple enumeration of components, without offering a critical synthesis of their synergistic integration. This review addresses this gap by arguing that the key advancement in PV/T-SWH systems is no longer incremental component design but the holistic integration of advanced materials such as nanofluids and PCMs with digital intelligence such as AI and machine learning. This manuscript provides a critical reassessment of this transition, outlining the evolution from flat-plate and concentrating collectors to the modern hybrid system. We consolidate the principal theoretical frameworks necessary for their design and conclude that the future challenge lies not in technical feasibility but in economic viability and standardization. This review therefore, serves as a roadmap for leveraging material-digital synergy to overcome commercialization barriers and unlock the full potential of the PV/T-SWH system.

The primary objective of this study is to advance the thermodynamic understanding and operational efficiency of flat-plate solar collectors by conducting an exergy-based optimization using real collected experimental data. To achieve this, the research explicitly avoids simplifying assumptions frequently adopted in previous works—including constant overall heat loss coefficient and equalization of inlet fluid temperature to ambient—and instead incorporates actual measured variations from a closed-loop experimental setup. Key scientific contributions include: (i) systematic evaluation of upper, lower, and side reflectors alone and in conjunction with focusing lenses, (ii) quantification of the dynamic behavior of the overall loss coefficient, and (iii) derivation of scenario-specific optimum operational parameters for exergy efficiency based on measured flow rates, solar flux, and inlet temperature. The study reveals that the use of reflectors alone resulted in the highest daily energy efficiency at 55.6

With rising global climate concerns, the countries worldwide are swiftly turning toward renewable energy. This study includes an approach to extract such resources by using an integrated desalination system based on direct contact membrane to desalinate water. A flat plate pancake-type solar thermal collector has been used to enhance the thermal efficiency. It includes copper tubes to exchange the energy absorbed. A direct contact membrane desalination unit is used to absorb energy effectively. The performance evaluation of the system is experimentally done under the climatic conditions of Jamshoro, Pakistan. This study aims at evaluating the efficiency and performance of the thermal collector and the desalination unit. The experimental results indicate that the freshwater production rate of 5.64 l/m2h with relatively low total dissolved solids of 40. The modification in the shape of the thermal collector proved as a more efficient system as it offers less resistance to the flow of fluid and the average consumption of energy is 696.84 W. The maximum overall efficiency of this Pancake-shaped thermal collector is found about 98%, and the temperature difference maximum achieved between the inlet and outlet is 44.8 degrees C.

This paper provides a comprehensive bibliometric analysis of voluntary carbon markets (VCMs), identifying key contributors, influential research works, thematic developments, and emerging trends from 765 scholarly publications sourced from the Web of Science Core Collection (1994–2024). Using VOSviewer and CiteSpace software, the study examines leading countries, institutions, authors, and highly cited documents shaping the VCM research landscape. Findings indicate dominant research clusters centered around carbon market mechanisms, environmental impact assessments, policy frameworks, corporate responsibility, and public engagement. The study underscores critical issues of additionality and leakage in carbon offset projects, highlighting the importance of robust monitoring and verification practices. Gaps identified include inadequate ground-level empirical data collection and limited involvement of Global South researchers. Future research directions emphasize technological innovations, improved transparency, stronger global regulatory integration, and expanded public awareness and participation to enhance the effectiveness and credibility of VCMs. This analysis offers valuable insights for scholars, policymakers, and market practitioners committed to advancing voluntary carbon markets towards meaningful climate action.

This study investigates the performance improvement of an evacuated tube solar collector (ETSC) using Al2O3/ water nanofluids, focusing on energy, exergy, and economic aspects. The thermophysical properties of Al2O3/ water nanofluids, including density, specific heat capacity, and thermal conductivity, were experimentally determined, with stability validated through zeta potential analysis. Two volume fractions (0.05% and 0.3%) were tested at flow rates of 1, 2, and 3 LPM under varying solar irradiance. The nanofluids significantly improved thermal performance, with the highest thermal and exergy efficiencies of 68% and 30.76%, respectively, achieved using 0.05% Al2O3/water nanofluid at 3 LPM. A comparison is also conducted between the proposed system and previously published literature using TiO2/H2O nanofluid. Results suggest that Al2O3/H2O nanofluids demonstrated 5.32% greater thermal efficiency as well as weight and cost reduction of about 85.5% and 69.15%, respectively at a lower volume fraction over TiO2/H2O nanofluid. A life cycle analysis, including energy requirement, CO2 emissions, and 20-year investment, is conducted to assess the system's environmental and economic feasibility. Life cycle analysis revealed a significant reduction in CO2 emissions and total costs for the solar-powered system. Furthermore, predictive modeling using CatBoost and AdaBoost achieved high accuracy, with CatBoost emerging as the superior model for generalization and prognostic efficiency. This work underscores the potential of Al2O3/water nanofluids for sustainable and cost-effective solar thermal applications.

Geothermal energy is a reliable and sustainable renewable energy source due to its continuous availability and eliminating the need for energy storage systems. Among various types of geothermal power plants, double flash (DF) geothermal plants are among the most widely utilized. This paper presents a comprehensive thermodynamic analysis of a DF geothermal power plant, integrating energy, exergy, economic, and exergoenvironmental (4E) evaluations. The study examines the influence of key parameters, including the high‐pressure separator and geothermal production well temperature, on the system performance. The results indicate that the expansion valve of the high pressure separator exhibits the highest exergy destruction rate (EDR) followed by the steam trubine, while both high‐ and low‐pressure separators experience no exergy destruction. The energy and exergy efficiencies are found to be 13.3% and 51.23%, respectively. The condensation heat rate is obtained around 46.551 MW, suggesting potential use for district heating applications. Additionally, the findings demonstrate that increasing the geofluid source temperature and the pressure of high‐pressure separator 1 lead to a decrease in the unit exergy cost, but an increase in overall cost rate, highlighting important trade‐offs for optimizing plant performance.

This study carries out an original thermoeconomic assessment of a hybrid energy system that mixes modified geothermal technology with LNG cold energy to produce sustainable hydrogen. The innovative configuration uses three main parts: a geothermal plant that works in a special way and uses hydraulics instead of usual expansion valves, a water-powered PEM electrolysis plant from a dual-effect desalination facility, and an LNG unit for converting cold energy. Thorough assessments prove that the system has superior technical features, saving 67.4 % of energy and 38.7 % of exergy, as well as producing electricity with 11.01 % efficiency. There is a total of 2.18 MW of exergy destruction, where the desalination part is responsible for approximately half, and the facility remains profitable at $0.021 per kWh by spending $2.02 million a year on operations. Parametric results indicate that increasing the geothermal turbine inlet pressure does not change the exergy efficiency by much and only increases water productivity, while pumping LNG at 70 bar improves all the system's performance. With these changes, the coefficient of performance goes up to 0.29 and each of the aforementioned efficiencies rises, proving that the solution offered here is practical.

This paper explores the use of industrial sludge as a renewable energy source, addressing challenges in sustainable energy production and waste management. It investigates the varied composition and properties of sludge from sectors like wastewater treatment, power generation, and chemical production, highlighting its potential for energy recovery. The paper provides an elemental analysis to underscore the energy content of different sludge types and examines methods for converting sludge into viable energy resources. Techniques such as anaerobic digestion, pyrolysis, gasification, and advanced thermal and electrochemical conversions are evaluated for their feasibility, environmental impact, and economic implications. The research emphasizes optimizing these methods for integration into existing energy systems and the importance of comprehensive cost and environmental impact assessments. It identifies main challenges in sludge conversion, including high moisture content and the presence of contaminants, underlining the need for effective management strategies. Future research directions proposed include diversifying across industries, refining energy extraction methods, conducting thorough environmental assessments, and developing supportive policies for this innovative approach. The paper concludes with a call for collaborative stakeholder efforts to advance this sustainable energy paradigm, highlighting the significant contribution of harnessing industrial sludge's energy potential for a more sustainable and environmentally friendly future.

To create freshwater, desalination procedures use a lot of electricity and heat from fossil fuels. Solar desalination has recently gained popularity as a practical technique for sustainably producing freshwater with little negative environmental effects. A solar photovoltaic (PV) thermal collector is a system that combines a solar PV and solar thermal collector to produce electricity and heat at the same time. The current work analyzes desalination systems that integrate PV thermal collectors, including membrane distillation, solar stills, humidification dehumidification, multiple-effect distillation, reverse osmosis (RO), and multiple-stage flash. The main goal is to successfully utilize the heat and power produced by the PV thermal collector in desalination systems to lower costs, use less primary energy, and enhance system efficiency. There are new prospects for improving and exploring PV thermal-driven desalination systems. Other desalination systems, such as electrodialysis, forward osmosis (FO), vapor compression, adsorption desalination, etc., may also use PV thermal collectors as an energy source. Comparative investigation demonstrates that desalination systems linked with a separate PV panel and solar thermal collector perform worse overall than systems connected with a PV thermal coupled system. Even if the initial expenses are slightly higher, photovoltaic thermal (PVT) desalination opens the door for stand-alone desalination in remote locations.

A computational fluid dynamic (CFD) and machine learning approach is used to investigate heat transfer on NASA airfoils of type NACA 0012. Several different models have been developed to examine the effect of laminar flow, Spalart flow, and Allmaras flow on the NACA 0012 airfoil under varying aerodynamic conditions. Temperature conditions at high and low temperatures are discussed in this article for different airfoil modes, which are porous mode and non-porous mode. Specific parameters included permeability of 11.36 x 10-10 m2, porosity of 0.64, an inertia coefficient of 0.37, and a temperature range between 200 K and 400 K. The study revealed that a temperature increase can significantly increase lift-to-drag. Additionally, employing both a porous state and temperature differentials further contributes to enhancing the lift-to-drag coefficient. The neural network also successfully predicted outcomes when adjusting the temperature, particularly in scenarios with a greater number of cases. Nevertheless, this study assessed the accuracy of the system using a SMOTER model. It has been shown that the MSE, MAE, and R for the best performance validation of the testing case were 0.000314, 0.0008, and 0.998960, respectively, at K = 3. However, the study shows that epoch values greater than 2000 increase computational time and cost without improving accuracy. This indicates that the SMOTER model can be used to classify the testing case accurately; however, higher epoch values are not necessary for optimal performance.

This study attempted to identify the effect of optimized intake manifold geometry on the behaviors and emission level of hydrogen compressed natural gas (H2CNG) fueled engine. For this purpose, a commercial Hyundai Sonata spark ignition engine (SIE) is modified to operate with CNG and hydrogen blend. The optimal intake pipe length was predicted using an analytical acoustic method. A new intake manifold is designed and implemented utilizing natural supercharging managed by over-pressure waves acoustic propagation. Several tests are conducted on the engine using the new manifold with a speed range from 1000 to 5000 rpm. Based on various engine speeds, the variation of brake torque (BT), in -cylinder pressure, NOx and CO emissions investigated by using gasoline, CNG and hydrogen CNG blend (HCNG) fueled engines via external mixtures. The first finding of the study is that the novel geometry improves the in -cylinder pressure by 10% at 3500 rpm. However, high engine speeds show a reduction of 14% in NOx and 40% in HC while speeds below 2000 rpm reduce CO by 40%. The second finding is that the new optimized geometry serves to get rid of both the auto-ignition and the backfire for high ratio of hydrogen in the blend.

Maintaining soil fertility and structure in Libya requires attention to water quality and irrigation practices due to limited arable land. This study aims to assess groundwater quality in the Brack-Ashkada, Libya agricultural project based on physicochemical parameters such as electrical conductivity, total dissolved solids, total hardness, and irrigation water quality index (IWQI), as well as some cations and anions, and irrigation indices such as sodium adsorption ratio (SAR), residual sodium carbonate, percentage sodium, permeability index, Kelly's index, potential salinity, total hardness (TH), and magnesium hazards percentage. The results indicated that IWQI is positively correlated with SAR and TH and negatively correlated with the remaining indices. Based on the irrigation indices, the groundwater of the three wells was suitable for irrigation and can be classified as moderately water-restricted. The Piper diagram suggests that the mixed-type Ca-Mg-Cl-SO4 was dominant in the wells. The study concludes that groundwater is partially safe for agricultural use, but specific safety measures must be taken. These findings will assist farmers in enhancing soil management, crop cultivation, and land sustainability.

The accelerated growth in renewable energy systems offers resolutions for reaching clean and sustainable energy production. Electrical Energy Systems (ESS) present indispensable tools with diverse applications to satisfy intermittent characteristics of renewable energies and enable the transition to clean energy production. The applied methodology to assess and review the hybridization concept summarizes the employments of the technical evaluations in the mutual resolutions between the energy production and consumption sectors while the high-efficiency EES has been considered as a synchronizer. Optimized smart grids and microgrids benefit from EES, making energy systems more efficient and reliable. The rise of electric vehicles as an eco-friendly transportation solution also depends on EES to overcome energy storage challenges. The novel aim of this work lies in the elaboration of the large-scale EES for storing and harvesting energy for effective peak-shaving purposes. This multidisciplinary review put a higher emphasis on the essence of the interconnection between different industrial subdivisions for environmentally benign, high-efficiency, and economical process reflections. Mechanical energy storage, thermomechanical energy storage, thermal energy storage, chemical energy storage, electrical energy storage, and electrochemical energy storage are the involved concepts in this study. These divisions collectively form a comprehensive strategy for optimizing energy utilization. RE sites increasingly utilize energy storage systems to enhance system flexibility, grid stability, and power supply reliability. Whether the primary energy source is solar, wind, geothermal, hydroelectric, or oceanic, EES provides the critical ability to store and manage energy efficiently.