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IntroductionThe increasing global demand for sustainable energy solutions highlights the urgency of exploring renewable resources, particularly sunlight, which is abundant and virtually limitless. This study reviews innovative technologies like solar trees, wind trees, and hybrid solar-wind trees, which are emerging as efficient structures for harnessing renewable energy.MethodsA comprehensive SWOT analysis was conducted to evaluate the strengths, weaknesses, opportunities, and threats associated with solar, wind, and hybrid trees. The analysis also considered sustainability aspects, focusing on the efficiency and practicality of these technologies in various settings.ResultsSolar trees mimic natural foliage, utilizing solar modules to convert sunlight into electricity, while wind trees incorporate micro-wind turbines and solar panels, effectively harnessing both wind and solar energy. Hybrid solar-wind trees combine these technologies to provide a consistent energy supply. These structures are compact, cost-effective, and adaptable to urban landscapes.DiscussionChallenges such as land use, aesthetic considerations, and public perception were identified. The review emphasizes the need for future research to optimize configurations and address these challenges, ensuring the successful integration of these technologies into sustainable urban landscapes.ConclusionThis review provides critical insights for renewable energy researchers, particularly in the development of hybrid wind and solar power systems, promoting energy security and climate resilience.

MXene, a two-dimensional (2D) carbide, carbonitride, and nitride, was discovered in 2011. A certain number of elements in the periodic table have contributed to the synthesis of MXene from the beginning to the present. Most researchers, however, are focused on a particular type of MXene, Ti3C2Tx, although the scientific community seldom considers the synthesis cost of this outstanding and potentially helpful substance. Herein, we explore the cost of MXene by going through each stage of the production process. Instead, the actual cost may vary by a small margin due to differences in the materials and procedures. However, this study provides a clear understanding of the cost, which is governed by the steps directly involved in the synthesis and characterization of MXene. The cost associated with various essential characterization tools like scanning electron microscope (SEM), transmission electron microscope (TEM), ultraviolet–visible spectroscopy (UV–Vis), and x-ray diffraction (XRD) is necessary to ensure the successful synthesis of MXene. All local expenses are converted into USD, except for the instrumental life cycle analysis and infrastructure cost values. The cost of each gram of MXene is predicted to be $20.33. The predicted cost is close to the market price of MXene, proving the accuracy of the cost calculation presented in this research. This work will assist the scientific community in planning and optimizing MXene's synthesis procedures so that the production cost can be potentially reduced if this material is produced on a larger scale.

Primary material supply is the heart of engineering and sciences. The depletion of natural resources and an increase in the human population by a billion in 13 to 15 years pose a critical concern regarding the sustainability of these materials; therefore, functionalizing renewable materials, such as nanocellulose, by possibly exploiting their properties for various practical applications, has been undertaken worldwide. Nanocellulose has emerged as a dominant green natural material with attractive and tailorable physicochemical properties, is renewable and sustainable, and shows biocompatibility and tunable surface properties. Nanocellulose is derived from cellulose, the most abundant polymer in nature with the remarkable properties of nanomaterials. This article provides a comprehensive overview of the methods used for nanocellulose preparation, structure–property and structure–property correlations, and the application of nanocellulose and its nanocomposite materials. This article differentiates the classification of nanocellulose, provides a brief account of the production methods that have been developed for isolating nanocellulose, highlights a range of unique properties of nanocellulose that have been extracted from different kinds of experiments and studies, and elaborates on nanocellulose potential applications in various areas. The present review is anticipated to provide the readers with the progress and knowledge related to nanocellulose. Pushing the boundaries of nanocellulose further into cutting-edge applications will be of particular interest in the future, especially as cost-effective commercial sources of nanocellulose continue to emerge.

Thermal energy storage (TES) and harvesting is an effective technique for optimum building thermal management. Phase-change materials (PCMs) are commonly used for TES applications but are troubled by their degraded thermal conductivity. Recent research progress in latent heat energy storage using PCMs and nano additives provides a viable solution for solar TES. A series of hybrid nano-enhanced phase change materials (HNePCMs) were prepared via two-step synthesis. Hybrid graphene–silver nanofillers were dispersed in commercial paraffin (melting point 25 °C) under different dispersion rates (0.1%, 0.3%, 0.5%). Different characterization techniques, e.g., FESEM, FT-IR, UV-VIS, TGA, XRD, DSC, and Tempos, were used in material characterization. A maximum enhancement of 6.7% in latent heat and 5% in heat storage efficiency was noted for nanocomposites with 0.3 wt% of additives. The nanocomposite with 0.3 Wt% showed great potential in shielding UV rays and showed a reduction of 6.5% in bandgap energy. Furthermore, the thermal conductivity of samples was boosted by a maximum of 90% (from 0.2 W/mK-0.39 W/mK) with 0.3 wt% dispersion of graphene–silver nanofillers. The thermophysical characterization results establish that the synthesized paraffin/graphene–silver hybrid nanocomposites are well suited for building thermal management.

Low thermal conductivity is the major obstacle for the wide range utilization of phase change materials (PCMs), especially organic PCMs, for most practical applications in thermal engineering. This study investigates the potential of enhancing the charging and discharging rates of organic PCM (RT44HC) by introducing polyethylene glycol (PEG) and activated carbon macroparticles (ACMPs). Different concentrations of PEG and ACMPs ranging from 0.3 wt% to 2 wt% were tested separately. The optimized concentrations found were used as dual reinforcements to attain the highest possible thermal conductivity. The specimens were tested for a complete charging–discharging cycle using an improvised thermal apparatus. Use of ACMP alone resulted in a minimal reduction in complete charging–discharging time due to the settlement of ACMPs at the bottom after 2–3 heating–cooling cycles. However, the addition of PEG with ACMPs exhibited a reduction in charging–discharging time due to the formation of a stable dispersion. PEG served as a stabilizing agent for ACMPs. The lowest charging–discharging time of 180 min was exhibited by specimens containing 1 wt% PEG and 0.5 wt% ACMPs which is 25% lower compared to bare PCM.