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The study focused on investigating the convective heat transfer of nano-encapsulated phase change suspensions in the presence of a non-uniform magnetic field within an annuli space between two square cylinders. The principal equations for the fluid flow and phase change heat transfer were formulated as partial differential equations and then represented into dimensionless format. The finite element method was used to solve these equations and simulate the free convection heat transfer. The effect of various factors, including Hartmann, Rayleigh, Eckert and Stefan numbers, geometry aspect ratio, nanoparticles’ concentration, and fusion temperature, on the heat transfer rate was examined. A neural network was also introduced and trained to establish the connection between the control parameters (inputs) and the heat transfer rate (output). The outcomes were presented in the form of the modified Nusselt number, along with isotherms, heat capacity ratio (phase change) contours, and streamlines. The results demonstrated that the neural network could accurately predict the heat transfer rate and provide a comprehensive map of heat transfer with respect to the control parameters. Nano-Encapsulated Phase Change Materials (NEPCMs) can be considered as a new type of nanofluids, in which the nanoparticle consists of a core and a shell. The core part is made of a Phase Change Material (PCM) which can undergo solid-liquid phase change at a certain fusion temperature, and absorb/release a significant amount of energy due to latent heat of the phase change.

Efficient energy conversion and utilization remain paramount in addressing the growing energy demand and environmental concerns. Concentrating photovoltaic thermal (CPVT) systems have emerged as promising solutions by integrating photovoltaic (PV) cells with thermal components for simultaneous electricity and heat generation. In this paper, we propose the application of the Boosted Regression Tree (BRT) algorithm to predict the entropy generation rate in a CPVT system equipped with a perforated twisted tube turbulator. Brief introduction of numerical analysis of local and global rates of frictional (S˙fr) and thermal (S˙th) irreversibilities in a CPVT system equipped with a perforated twisted tube turbulator. The results approve the efficacy of the BRT algorithm in predicting the entropy generation rate. Through comprehensive simulations and data analysis, we establish a predictive model that considers factors such as solar irradiance, fluid flow rate, tube geometry, and turbulator characteristics. The BRT model exhibits remarkable accuracy in capturing the nuanced interplay of these factors, enabling reliable estimations of entropy generation rate.

In the realm of internal combustion engines, there is a growing utilization of alternative renewable fuels as substitutes for traditional diesel and gasoline. This surge in demand is driven by the imperative to diminish fuel consumption and adhere to stringent regulations concerning engine emissions. Sole reliance on experimental analysis is inadequate to effectively address combustion, performance, and emission issues in engines. Consequently, the integration of engine modelling, grounded in machine learning methodologies and statistical data through the response surface method (RSM), has become increasingly significant for enhanced analytical outcomes. This study aims to explore the contemporary applications of RSM in assessing the feasibility of a wide range of renewable alternative fuels for internal combustion engines. Initially, the study outlines the fundamental principles and procedural steps of RSM, offering readers an introduction to this multifaceted statistical technique. Subsequently, the study delves into a comprehensive examination of the recent applications of alternative renewable fuels, focusing on their impact on combustion, performance, and emissions in the domain of internal combustion engines. Furthermore, the study sheds light on the advantages and limitations of employing RSM, and discusses the potential of combining RSM with other modelling techniques to optimise results. The overarching objective is to provide a thorough insight into the role and efficacy of RSM in the evaluation of renewable alternative fuels, thereby contributing to the ongoing discourse in the field of internal combustion engines.

The most interesting themes worldwide are those relating to sustainable water and energy supplies. They have a significant impact on any society's economic wellbeing. Desalination of brackish water has proven to be a good solution to the freshwater issue that many regions of the world face. Solar stills (SSs) are a simple distillation technique for freshwater purification. From the conventional SSs to the modified SSs, several studies have been carried out to improve the effectiveness of this technique. Pyramid solar stills are effective and efficient, according to researches that have been done to develop several types of solar stills for increased distillate production. In this review, we aim to provide an extensive review of recent advancements in pyramid solar distillation techniques, including new technologies, methods, and best practices. Consequently, this paper helps researchers choose the optimal technique to get the best-optimized productivity from a pyramid solar still. This review highlights the efforts of researchers to improve the efficiency of solar distillation systems by exploring recent techniques and innovations in pyramid solar distillers up to 2023. Various results have demonstrated the significance of modifications or improvements to pyramid SSs, such as utilizing storage materials, which can significantly increase productivity by approximately 35%. Additionally, a v-corrugated absorber with PCM can enhance the yield by about 87.4%. Furthermore, the use of wick materials can increase freshwater production by up to 122%, with jute wick outperforming cotton wick. Integrating evacuated tubes and carbon black nanofluid into a pyramid solar still can also improve freshwater production by approximately 57.1%. Combining nano and wick materials can further boost pyramid distiller productivity by up to 176% and increase thermal efficiency to 60.44%. Moreover, using pyramid distillers with revolving cylinders and electrical heaters can result in a daily output increase of 214%, producing up to 9100 ml/m2/day.

Zeolite desiccant particles are well known for their strong affinity to adsorb water vapor molecules; however, they require significant regeneration energy to be created. This paper presents an experimental study of the adsorption and regeneration processes of a monolayer zeolite for indoor dehumidification to the 13X zeolite beads with a 4 × 8 mesh bead size and a pore opening 10 A⁰ were used as this monolayer. An experimental investigation was conducted to determine the effects of the relative humidity, temperature, and air flow rate on the adsorption and regeneration processes. The results show the effectiveness of the monolayer coating method and the relative humidity significantly affects the adsorption process, and that the airflow rate surrounding and through the zeolite beads increases the adsorption and desorption of the water vapor molecules. In the absence of the meniscus radius formation due to the monolayer arrangement prevents external condensation. With an airflow rate of Re = 1773, the full adsorption process at a relative humidity of 99% was obtained within 37 min; meanwhile, the regeneration process proceeded at 100 °C within 66 min. The adsorption time was reduced by 27% and 43% as the Reynold number increases to 2586 and 3325, respectively. Likewise, the effectiveness of the regeneration time is decreased by 0.07% and 14% within the same Reynold number increases. Results obtained from this research can be used to guide the future development of polymer-coated energy exchangers.

‏ Manipulating in fuel injection strategies and introduce renewable fuel in diesel engine can provide clean combustion and lower pollutant emissions. The effect of fuel injection pressures (FIPs) and RME on combustion characteristics, NOx emissions and soot nanoparticle emissions when rapeseed methyl esters was used have been investigated at 1500 rpm and two brake mean effective pressure of 2.5 and 5 bar. A calibrated electrostatic mobility spectrometer (EMS) was used to measure the soot nanoparticle number size distributions. The peak cylinder pressure and heat release rates were evaluated when the FIP increased for all fuels studied. The results showed that further advanced in combustion with RME, meanwhile a shorter ignition delay from the fuel was exhibited in comparison with diesel fuel combustion under various FIP. Furthermore, the values of BSFC decreased by 3.7% and 17.8% from the RME combustion at high and low engine load, respectively. The reduction in NOx emissions was obtained when FIP increased during RME combustion in comparison with ULSD under low engine load. In contrast, RME generated higher NOx by 7% and lower soot nanoparticles by 27% compared to the ULSD under high engine load. RME combustion produced lower nucleation particle numbers in comparison with those emitted from ULSD under all engine operating conditions as well as the accumulation mode particles was higher for ULSD.

The energy sector is an intrinsically dynamic and complex system, and therefore its behaviour is not solely controlled by constituent components. Rather, it is a consequence of dynamic interactions among them. To properly manage such a system in a sustainable manner, it is necessary to understand the underlying dynamics of component interactions. Despite this, the interconnections between components of the energy sector in research and policy have received little attention. Here, we outline crucial limitations of previous efforts and emphasize the importance of using systems thinking in addressing the energy sector's sustainability challenges. We demonstrate this by a case study of the Australian energy sector, which has experienced emerging sustainability issues. Research findings show that current policies promoting energy development in the country are likely to be ‘fixes that fail’ that ultimately undermine sustainability. To achieve in building a sustainable energy sector, the policy must focus on implementing long-term solutions and avoid short-term quick fixes.

A numerical study of the Buoyancy-driven flow in a porous enclosure, having a bottom heated wavy wall, filled with Cu-Al2O3/water hybrid nanofluid is performed using the local thermal non-equilibrium model. The non-dimensional governing equations of fluid flow and heat transfer are solved using the Galerkin finite element method. The state variables change in the porous enclosure is represented using the Darcy-Brinkman model. The impacts of various effective parameters which include nanoparticle volume fraction (0 ≤ Φ ≤ 0.04), Darcy number (10−5 ≤ Da ≤ 10−2), modified conductivity ratio (0.1 ≤ γ ≤ 1000), the number of undulations (1≤ N ≤ 5) and the amplitude of waviness (0.05 ≤ A ≤ 2). The results showed that the Darcy number is the first controlling parameter on the fluid flow and temperature distributions followed by A, N and γ. Additionally, the heat transfer rate is increased by increasing the thermal conductivity of the nanoparticles reaching its maximum value at Φ = 0.04. Furthermore, by comparing the temperature fields of the fluid phase and solid matrix, it is clear that the effects of the local thermal non-equilibrium are significant at a low modified thermal conductivity ratio and high Darcy number.

Flat solar collectors are extensively utilized in various domestic and industrial applications to reduce energy consumption. In this study, an-active flat plate solar collector (FPSC) with an internal absorber tube receiver was fabricated and tested in Al-Samawa city, Iraq (latitude 31.19°N and longitude 45.17°E). The ambient temperature and incident solar radiation at the experimental location were reached 39 °C and 840 W/m2, respectively. In this study, the number of riser tubes connected to headers that are covered with a glass sheet in a conventional FPSC were replaced with a single serpentine-shaped collector tube covered with a plastic sheet. The proposed solar collector used a smooth copper tube with internal and exterior diameters of 9.5 and 12 mm, respectively, and a total length of 1000 mm. A TRNSYS model of a flat plate collector integrated with an absorber tube was developed, simulated, and validated using the experimental data. Temperature and flow rate data were obtained concurrently throughout the experiments to evaluate the performance of the fabricated solar collector. The temperature at the solar collector input stayed relatively constant at 37.7 °C, and the water flow rate remained constant at 0.75 L/min. The results indicated that the temperature at the solar collector output ranged from 52 to 61 °C, with an average of 58 °C. The efficiency of the proposed solar collector ranges from approximately 45% to 67%, with an average of 58%. Overall, the simulation results of the TRNSYS model are in excellent agreement with experimental data. The average discrepancy between the tests and simulations for temperature differential and collector efficiency is approximately 1%.

The performance of microchannel with sidewall dimples and fillet profile in the bottom surface is investigated. Two dimple sizes of (0.5 mm and 1 mm) are systematically clustered along the channels with and without fillet are considered. The laminar flow regime is assumed with Reynolds numbers ranging from 200 to 1200. The results show that the dimples and fillet profile have a significant effect on the thermal performance of microchannel. The Nusselt number of the microchannels with 1 mm dimples is 20% higher than the plain microchannel. However, an increase in pressure drop of 10% was obtained. In addition, the fillet profile impacts the thermal performance of microchannels without pressure drop penalty increase. Combining both dimples and fillet profile causes a significant enhancement in the thermal performance. Nusselt number of microchannels heat sink with 1 mm dimple size and fillet profile is 60% higher compared to the plain microchannel.