Building-integrated photovoltaics (BIPV) face significant efficiency losses due to operational overheating. This study numerically investigates a hybrid thermal management system combining phase change materials (PCMs) with embedded copper channel networks to address this challenge. This study addresses this gap through a numerical investigation of a hybrid thermal management system combining PCMs with embedded copper channel networks. Three configurations, PCM-only, PCM with U-channels, and PCM with W-channels, were evaluated using computational fluid dynamics (CFD) for PCM thicknesses of 3-5 cm and two PCM types (RT24HC and Lauryl Alcohol). The results demonstrate that channel geometry and PCM selection dictate a critical trade-off between passive cooling and active heat recovery-a novel finding that provides actionable design guidance. The W-channel configuration with a 5 cm layer of Lauryl Alcohol (LA) PCM proved optimal for passive cooling, maintaining the lowest interior wall temperature of 296.65 K, thereby reducing building cooling loads. Conversely, the U-channel configuration with a 3 cm layer of RT24HC (RT) PCM excelled at active thermal harvesting, achieving the highest outlet fluid temperature of 300.4 K and a heating rate of 0.0072 K/min. The Uchannel design also significantly delayed PCM thermal saturation, retaining a liquid fraction of just 0.10 compared to full melting in the baseline. This work provides validated, configuration-specific design strategies for high-efficiency BIPV systems, enabling enhanced electrical output and dual-function thermal energy utilization.

Achieving carbon neutrality in modern architecture requires energy-efficient passive design strategies that integrate green materials, smart technologies, and high-performance insulation. Windows and skylights play a critical role in Net-Zero Buildings (NZBs), demanding high transparency, superior thermal insulation, and year-round thermal comfort. This study introduces and investigates a novel smart composite material, polyethylene glycol-mediated silicon aerogel (Siag@PEG), as a transparent insulation material (TIM) with dual thermal and optical properties. A key innovation is the use of PEG as a solid-solid phase change material (PCM), which effectively resolves the potential leakage issues associated with solid-liquid PCMs when integrated into window glazing units. A comprehensive numerical model was developed to simulate phase transitions and thermal energy dynamics using a transient conjugate heat transfer approach coupled with the enthalpy-porosity method including thermal radiation. The thermal performance of a double-glazed window filled with Siag@PEG was evaluated and compared to conventional air-filled and pure PEG-filled systems under standard solar irradiance conditions (1 SUN, AM 1.5). Results demonstrate that an optimized Siag@PEG composite with a 5% mass loading of silica aerogel exhibits promising thermal benefits. Specifically, it achieved a decrease in indoor temperature and thermal gradients of 2.57 K, 3.39 K, and 6.41 K at 30, 60, and 90 min, respectively. The optimum energy consumption was determined to be 221.27 kJ/kg, yielding an impressive energy efficiency improvement rate (EEIR) of 86.45%. Furthermore, at the indoor glass surface of the double-glazed unit, the Siag/PEG@5% system showed superior inner heat transfer (−21.21 W), surface heat flux (−424.11 W/m2), and an EEIR of 22.02%, significantly outperforming conventional and pure PEG-filled window glazing systems. These findings reveal the optimal thermal and energy storage/release performance of the Siag@PEG composite, underscoring its significant potential to enhance the energy efficiency of transparent building envelopes and contribute to the realization of Net-Zero energy buildings.

As photovoltaics (PVs) scale from one to multiple terawatts over the next decade, ensuring sustainable deployment is urgently required. Crystalline silicon (c-Si) PVs, the current industry standard, will generate an estimated 160 million tonnes of waste by 2050, and there remains complex technoeconomic challenges associated with their recycling. Metal-halide perovskite (MHP)-based tandem PVs not only promise higher power conversion efficiencies than single-junction c-Si devices, but also offer intrinsic advantages for circularity, including simpler device architectures, low-temperature processing, and more accessible materials recovery routes. At this pivotal juncture when perovskite PVs begin to enter the market, this review examines the critical circularity challenges that must be addressed: substitution of scarce raw materials, scalable recycling protocols, cost-effective stack delamination, safe lead sequestration, and policy frameworks to encourage circularity across the device lifecycle with effective incentives. By integrating the materials, technoeconomic and policy dimensions that go beyond conventional lifecycle assessments, we outline actionable strategies to co-optimize device performance and sustainability. This review aims to guide researchers, policymakers, and industry stakeholders in steering perovskite-based tandem PVs towards a circular and responsible commercialization pathway within the global clean-energy transition.

The accumulation of dust, water, and other environmental contaminants on photovoltaic (PV) panel surfaces significantly reduces light transmission and overall energy conversion efficiency. To address this challenge, self-cleaning coatings based on hydrophobic and hydrophilic mechanisms have emerged as promising PV panel surface modification strategies. This review comprehensively explores recent developments in both hydrophobic and hydrophilic self-cleaning coatings tailored for photovoltaic applications. Hydrophobic coatings, characterized by high water contact angles, enable contaminant removal through water droplet roll-off, whereas hydrophilic coatings facilitate uniform water spread and removal via sheeting action. The article discusses various coating material’s design, including metal oxides, polymers, and nanocomposites, fabricated using techniques such as sol-gel processing, dip coating, spin coating, and chemical vapor deposition. Emphasis is placed on the influence of surface roughness, surface energy, and environmental durability on coating performance. Comparative analysis of these two self-cleaning strategies highlights their respective advantages, limitations, and suitability under different climatic conditions. Furthermore, the integration of multifunctional coatings—combining self-cleaning with anti-reflective, UV-resistant, and antimicrobial properties—is addressed as an emerging direction. The review concludes with insights into current challenges and future perspectives, aiming to guide the development of efficient, durable, and scalable self-cleaning solutions for long-term photovoltaic performance enhancement.

CuI is a well-known thermoelectric (TE) material recognized for its p-type characteristics. However, the development of its n-type counterpart and the integration of both p- and n-type CuI in thermoelectric generators (TEGs) remain largely unexplored. In this study, we successfully tuned the thermoelectric properties of CuI by strategically incorporating Ag, enabling the synthesis of both p-type (Ag0.2Cu0.8I) and n-type (Ag0.9Cu0.1I) materials using a cost-effective, greener, and scalable successive ionic layer adsorption and reaction (SILAR) method. The p-type Ag0.2Cu0.8I exhibited a figure of merit (ZT) of 0.47 at 340 K, driven by a high Seebeck coefficient of 810 μV·K-1. In contrast, the n-type Ag0.9Cu0.1I achieved an exceptional ZT of 2.5 at 340 K, attributed to an ultrahigh Seebeck coefficient of -1891 μV·K-1. These superior thermoelectric properties make CuI-based materials attractive alternatives to conventional TE materials, such as Bi2Te3 and PbTe, which are limited by toxicity and resource scarcity. Furthermore, a prototype thermoelectric glazing unit (5 × 5 cm2) demonstrated a 14 K temperature differential, highlighting its dual functionality in power generation and building heat loss mitigation. These findings underscore the potential of low-cost CuI-based materials for advancing sustainable energy technologies.

This study develops a transparent, biocompatible hydrogel membrane (HGM) for sustainable building fenestration. Made from hydroxypropyl cellulose, poly(acrylic acid), and starch derived from waste potato peels, the HGM leverages bio-waste valorization. It exhibits thermotropic behavior, dynamically adjusting optical transparency with temperature. Extensive physicochemical analyses confirmed the molecular interactions governing its optical and thermal properties. When incorporated into a prototype double-glazed window, the HGM significantly enhanced indoor thermal regulation, achieving a low thermal conductivity at 0.23 W m-1 K-1 and thermal transmittance (U-value) of 1.84 W m-2 K-1 and effectively mitigating temperature differentials of up to 30 degrees C. The synthesized hydrogel exhibits a tunable transition temperature, high luminous transmittance of 72%, notable solar modulation efficiency of 75%, and exceptional durability. In addition to thermal performance, the HGM improved the efficiency of the underlying silicon photovoltaic cell by up to 15% compared with its standalone performance. This enhancement is attributed to the presence of light-scattering centers within the HGM, which facilitate total internal reflection and contribute to thermal buffering. Functioning dually as a passive radiative cooling layer and an optical modulator, the HGM material demonstrates multifunctionality tailored for building-integrated photovoltaic systems. This study advances the domain of energy-efficient architecture by integrating sustainable materials with improved solar and thermal regulation properties, thereby promoting the development of climate-responsive building designs.

The progression of research in concentration photovoltaic systems parallels the advancement of high-efficiency multi-junction solar cells. To translate the theoretical optical framework into practical experimentation, a modular and structurally validated mechanical configuration for a high-concentration photovoltaic (HCPV) system was developed, incorporating boundary conditions and ensuring full system integration. The system incorporates a modular mechanical architecture, allowing flexible integration and interchangeability of optical components for experimental configurations. The architecture offers a high degree of mechanical flexibility, providing each optical stage with multiple linear and angular adjustment capabilities to support precision alignment. To ensure tracking precision, the system was coupled with a three-dimensional sun tracker capable of withstanding torques up to 60 Nm and supporting a combined payload of 80 kg, including counterbalance. The integration necessitated implementation of a counterbalance mechanism along with comprehensive static load analysis to ensure alignment stability and mechanical resilience. A reinforced triangular support structure, fabricated from stainless steel, was validated through simulation to maintain deformation below 0.1 mm under stress levels reaching 5 MN/m2, confirming its mechanical robustness and reliability. Windage analysis confirmed that the tracker could safely operate at 15 m/s wind speed for tilt angles of 35° (counter-clockwise) and −5° (clockwise), while operation at a 80° (counter-clockwise) tilt is safe up to 12 m/s, ensuring compliance with local environmental conditions. Overall, the validated system demonstrates structural resilience and modularity, supporting experimental deployment and future scalability.

Barium stannate (BaSnO3) has emerged as a promising alternative electron transport material owing to its superior electron mobility, resistance to UV degradation, and energy bandgap tunability, yet BaSnO3-based perovskite solar cells have not reached the efficiency levels of TiO2-based designs. This theoretical study presents a design-driven evaluation of BaSnO3-based perovskite solar cell architectures, incorporating MAPbI3 or FAMAPbI3 perovskite materials, Spiro-OMeTAD, or Cu2O hole transport materials as well as hole-free configurations, under varying light intensity. Using a systematic device modelling approach, we explore the influence of key design variables—such as layer thickness, donor density, and interface defect concentration—of BaSnO3 and operating temperature on the power conversion efficiency (PCE). Among the proposed designs, the FTO/BaSnO3/FAMAPbI3/Cu2O/Au heterostructure exhibits an exceptionally effective arrangement with PCE of 38.2% under concentrated light (10,000 W/m2, or 10 Sun). The structure also demonstrates strong thermal robustness up to 400 K, with a low temperature coefficient of −0.078% K−1. These results underscore the importance of material and structural optimisation in PSC design and highlight the role of high-mobility, thermally stable inorganic transport layers—BaSnO3 as the electron transport material (ETM) and Cu2O as the hole transport material (HTM)—in enabling efficient and stable photovoltaic performance under high irradiance. The study contributes valuable insights into the rational design of high-performance PSCs for emerging solar technologies.

The combined effect of TiO2 and CeO2 as the electron transport layer (ETL) in the hole transport layer (HTL)-free carbon-based perovskite solar cells (C-PSCs) to enhance performance characteristics is a less explored research area. In this context, we investigated the effect of morphology-tuned CeO2 in combination with TiO2 in the C-PSCs. Considering the light scattering effect in C-PSCs and the property of extending the light-traveling distance across the photoelectrode, we synthesized rod and cubic CeO2 nanostructures. The synthesized nanoparticles were used over the TiO2 layer, and their photovoltaic performance was compared to that of the TiO2-only C-PSC and analyzed by using impedance and quantum efficiency studies. The light-scattering effect on the C-PSCs, investigated with the diffused reflectance study, found that the rod structure of CeO2 provides better light travel toward the photosensitizer, and the highest power conversion efficiency (PCE) of nearly 12.5% was recorded for the rod-shaped CeO2 in the HTL-free C-PSC, which is 24% higher compared to a pristine TiO2-based C-PSC. Moreover, the devices with rod-shaped CeO2 demonstrated suitable charge transport properties along the perovskite layer and a lower charge recombination rate when compared with the cube structure. This work demonstrates a major breakthrough in the performance enhancement of HTL-free C-PSCs by nanomaterial morphology alteration and fabrication engineering, which can significantly influence future research.

Integrating PV solar cells with concentrators into window systems can not only generate electricity for a building, but also has the potential to enhance the thermal resistance of the building's windows without a significant sacrifice of light transmittance for passive daylight. A novel system, known as the crossed compound parabolic concentrator photovoltaic window, has been recently studied for its electrical properties. However, its thermal and optical performance, particularly in terms of the overall heat transfer coefficient (U-value) and total optical transmittance when integrated into a building, remains unexamined. These factors are crucial for predicting the system's impact on a building's energy efficiency and indoor comfort. Therefore, this paper aims to investigate the U-value of this window system under various temperature scenarios and the optical transmittance of the window at different incident angles. The thermal conductance was assessed through numerical simulations using a computational fluid dynamics model, which was validated by experimental measurements conducted in a large climate chamber. The optical transmittance was investigated using a validated 3D ray-tracing model. The total optical transmittance and electricity generation were calculated for typical sunny days in winter and summer under London's climate conditions. Additionally, alternative designs were developed to explore the impact of pitch between adjacent optics on the thermal conductance and optical transmittance of the window. The results showed that the window with a configuration of Dx = Dy = 5 mm (where Dx and Dy represent the horizontal and vertical pitches, respectively, between two adjacent solar optics) achieved the lowest U-value (2.566 W/m2 & sdot;K). This U-value is slightly lower than that of the original window design, which has a U-value of 2.575 W/m2 & sdot;K. The original window configuration with Dx = Dy = 1.77 mm produces the highest power output. Specifically, it generates 499.25 Wh/m2 on a typical sunny day in winter and 162.73 Wh/m2 on a typical sunny day in summer. However, it exhibits the lowest transmittance (14.6 % on a typical sunny day in winter and 25.2 % on a typical sunny day in summer, respectively), indicating that it is more suitable for buildings with a higher window-to-wall ratio to ensure an adequate amount of natural light. For buildings with a lower window-to-wall ratio, the CCPCPV window should be designed with a larger horizontal pitch, such as 15 mm and 30 mm, to meet indoor illuminance requirements while also providing enhanced thermal performance and additional power output.

The optical ultra-high concentration ratio levels are still not demonstrated enough due to the high complexity of the associated optical designs offering restricted angular freedom, and the expansive cost that might be required for such a breakthrough. This research proposes a novel optical design of an ultra-high concentrating photovoltaic system that can achieve a geometric concentration of 5831×. The system consists of four flat silicon-on-glass (SOG) Fresnel lenses as primary optics, four reflectors as secondary optics, and four-domed tertiary optical elements (TOE) that will refract the sunlight onto a 5.5×5.5mm2 triple-junction solar cell. A complete proof-of-concept module has been developed, assembled, and tested. The experiments were conducted based on instantaneous and one hour of continuous measurement. The obtained results showed that the system can achieve a higher effective concentration ratio of 1291 suns when deploying ReflecTech polymer compared to aluminium reflective film of 984 suns and PilkingtonOptimirror of 1220 suns. The developed and tested compact ultra-high concentrator photovoltaic system yielded the highest geometrical concentration ratio and the highest effective concentration ratio achieved experimentally.

AbstractTo address the pressing need for reducing building energy consumption and combating climate change, thermoelectric glazing (TEGZ) presents a promising solution. This technology harnesses waste heat from buildings and converts it into electricity, while maintaining comfortable indoor temperatures. Here, we developed a TEGZ using cost-effective materials, specifically aluminium-doped zinc oxide (AZO) and copper iodide (CuI). Both AZO and CuI exhibit a high figure of merit (ZT), a key indicator of thermoelectric efficiency, with values of 1.37 and 0.72, respectively, at 340 K, demonstrating their strong potential for efficient heat-to-electricity conversion. Additionally, we fabricated an AZO-CuI based TEGZ prototype (5 × 5 cm²), incorporating eight nanogenerators, each producing 32 nW at 340 K. Early testing of the prototype showed a notable temperature differential of 22.5 °C between the outer and inner surfaces of the window glazing. These results suggest TEGZ could advance building energy efficiency, offering a futuristic approach to sustainable build environment.

This paper explores the utilisation of horizontally and vertically converging microchannel heat sinks for cooling concentrator photovoltaic systems. These are compared to a straight microchannel, which is used as the control test. The primary performance parameters considered are the system’s energy and exergetic efficiency and the thermal stresses generated in the solar cell. Horizontally converging channels yield more uniform temperature distributions, but the peak and average thermal stress generation increased due to the higher cell temperature. Conversely, vertically converging channels demonstrated a reduction in thermal stress generation. However, channels which converge more sharply require a substantial increase in pumping power for the same cooling-fluid flow rate which negatively impacts energy and exergetic efficiency. Notably, the control design for straight microchannels is specified to have the same manufacture difficulty across configurations, which is an often-overlooked aspect.The evaluation incorporates two irradiance profiles from concentrator optics to enhance the applicability of results. The straight microchannel structure and the vertically converging channel with a taper ratio of 0.75 are identified as the most applicable for concentrator photovoltaic application. The outcomes provide valuable insights on heat sink design and sheds light on the trade-offs between thermal performance, energy efficiency and manufacturability.

AbstractLaser wireless energy transmission is a widely utilized method, yet its efficiency is constrained by a variety of factors. In order to improve the conversion efficiency of the receivers of the laser wireless power transmission (LWPT) system, the square elliptic hyperboloid (SEH) concentrating module designed for LWPT system receivers is developed. By analysing the I–V characteristic curves from the results of the experiments and employing non‐linear parameter regression, a corrected battery characteristic curve was derived within a specific laser irradiation range. On this basis, an optical–thermal–electric multi‐field coupling characteristic model was developed. The finite element method is used to simulate the multi‐field coupling characteristics and conversion efficiency of the receiving end under diverse working conditions (including different rotation angles and different divergence angles) of the concentrating photovoltaic module. Research shows: First, the larger the divergence half‐angle β of the laser beam, the more obvious the improvement of the effective optical efficiency of the system by the SEH concentrator. Second, the short‐circuit current and the maximum output power of the PV cell at the receiving end are significantly improved by the SEH concentrator, and the improvement effect is more obvious with the increase of the divergence angle and the rotation angle. Third, SEH concentrators did not significantly affect the fill factor of PV cells.

Phase Change Materials (PCMs) present cutting-edge technology with substantial promise for advancing sustainable and energy-efficient cooling in buildings. These materials can absorb and release latent heat during phase transitions, facilitating thermal energy storage and temperature regulation. This comprehensive literature review explores various strategies and methods for implementing passive cooling with PCMs in buildings. The integration of PCMs enhances multiple passive cooling approaches, including solar control, ground cooling, ventilation-based heat dissipation, radiative cooling, and thermal mass-based heat modulation. The analysis delves into PCM classifications, encapsulation techniques, melting enthalpies, integration into diverse building envelopes, and performance across different climates. The findings from this comprehensive review indicated that PCM walls introduce a 2-hour delay in heat transfer and mitigate external temperature fluctuations. Windows equipped with PCM panels reduce heat transfer by 66 %. Combining PCMs with nocturnal radiative cooling leads to interior surface temperature reductions exceeding 13 degrees C. Natural ventilation with PCMs results in notable energy savings of up to 90 % in hot climates. The combination of free cooling and PCM thermal storage reduces charging times by 35 % while enhancing heat transfer. Simulations performed in the open literature suggested that strategic placement of PCMs in lightweight building walls reduces heat flux and overall energy consumption. Despite facing challenges related to scalability, compatibility, reliability, and recycling, PCM solutions demonstrate robust potential. When integrated thoughtfully into building design, PCMs significantly improve thermal performance and energy efficiency. Experimental validations confirm energy reductions ranging from 14 % to 90 %, underscoring the adaptability of passive cooling techniques leveraging PCM thermal storage and heat transfer capabilities across various climates.

Most electronic devices are powered by electricity, and the transfer of energy to related electronic devices is a critical issue. Laser wireless power transmission(LWPT) has a broad prospect in the field of wireless energy transmission, such as distributed charging system (DLC), spacecraft sensor network, satellite-to-satellite communication and medium and long distance power transmission, ground to unmanned aerial vehicle (UAV), and so on. In this paper, a multi-field coupled model of LWPT system for laser transmission at medium and long distances is established. Through the existing LWPT experimental platform and test, the test obtained the correlation coefficient of the I-V relationship formula with the change of light intensity and temperature. On the basis of the modified parameters, the attenuation efficiency of laser power with transmission distance is calculated, and the heat transfer and electrical characteristics of photovoltaic cells are solved by finite element method. It is found that different atmospheric environment and laser transmission distance have obvious effects on the voltage, current and temperature variation of photovoltaic cells. The temperature of a photovoltaic cell has a huge impact on its output efficiency. The temperature can be controlled effectively by setting the laser interval of pulse mode reasonably. The cooling capacity of photovoltaic cells is the key to improve the electrical conversion efficiency of LWPT systems.

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Considering environmental concerns, electric vehicles (EVs) are gaining popularity over conventional internal combustion (IC) engine-based vehicles. Hybrid energy-storage systems (HESSs), comprising a combination of batteries and supercapacitors (SCs), are increasingly utilized in EVs. Such HESS-equipped EVs typically outperform standard electric vehicles. However, the effective management of power sources to meet varying power demands remains a major challenge in the hybrid electric vehicles. This study presents the development of a MATLAB Simulink model for a hybrid energy-storage system aimed at alleviating the load on batteries during periods of high power demand. Two parallel combinations are investigated: one integrating the battery with a supercapacitor and the other with a photovoltaic (PV) system. These configurations address challenges encountered in EVs, such as power fluctuations and battery longevity issues. Although batteries are commonly used in conjunction with solar PV systems for energy storage, they incur higher operating costs due to the necessity of converters. The findings suggest that the proposed supercapacitor–battery configuration reduces battery peak power consumption by up to 39%. Consequently, the supercapacitor–battery HESS emerges as a superior option, possibly prolonging battery cycle life by mitigating stress induced by fluctuating power exchanges during the charging and discharging phases.