Passive cooling of buildings has become increasingly important for green and low-carbon development, especially in the near decade where daytime radiative cooling technology (DRCT) has drawn ...attention with big breakthroughs. However, irresistibly importing heat from sunlight and surroundings results in notable temperature rise, thus limiting the cooling effect. Here, we report a radiative paint with latent heat storage capacity to store imported heat by coupling randomly-distributed phase-change materials (PCMs) based microcapsules with acrylic resin to enhance cooling performance. The bifunctional paint shows good performance in selected-suitable phase transition temperature, high enthalpy, high reflectivity in the sunlight region and strong emissivity in the atmospheric window region. The temperature measurements demonstrate that the paint possesses enhanced cooling performance of temperature drop and time buffering effect compared with the pure radiative cooling paint. This work offers the potential to broaden the applications of PCMs and DRCT for energy saving and environment protection.
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•Bifunctional paint with radiative cooling and latent heat abilities was developed•Phase-Change Materials used for isothermal storage of importing heat•High reflectivity of paint derived from micro size distribution of the microcapsules•Temperature drop and time buffering effect was achieved by bifunctional paint
Phase transitions; Applied sciences; Materials science
Thermal energy plays an indispensable role in the sustainable development of modern societies. Being a key component in various domestic and industrial processes as well as in power generation ...systems, the storage of thermal energy ensures system reliability, power dispatchability, and economic profitability. Among the numerous methods of thermal energy storage (TES), latent heat TES technology based on phase change materials has gained renewed attention in recent years owing to its high thermal storage capacity, operational simplicity, and transformative industrial potential. Here, we review the broad and critical role of latent heat TES in recent, state-of-the-art sustainable energy developments. The energy storage systems are categorized into the following categories: solar-thermal storage; electro-thermal storage; waste heat storage; and thermal regulation. The fundamental technology underpinning these systems and materials as well as system design towards efficient latent heat utilization are briefly described. Finally, the exciting research opportunities available to further improve the overall energy efficiency of integrated TES systems are discussed.
This review highlights the broad and critical role of latent heat storage in sustainable energy systems including solar-thermal storage, electro-thermal storage, waste heat storage and thermal regulations.
Thermal energy storage and utilization is gathering intensive attention due to the renewable nature of the energy source, easy operation and economic competency. Among all the research efforts, the ...preparation of sustainable and advanced phase change materials (PCMs) is the key. Cellulose, the most abundant natural polymer on earth, has the advantages of renewability, biodegradability, recyclability and ease of functionalization, making it a versatile candidate for newly emerging energy applications. Incorporating nanocellulose into PCMs has undergone a booming development as it can overcome the drawbacks of PCMs and form multifunctional sustainable composites. This review summarizes the use of nanocellulose including cellulose nanocrystals and cellulose nanofibers in the field of latent heat storage (LHS). Firstly, the preparation, physical properties and surface modification of nanocellulose are systematically reviewed, followed by the illustration of the preparation of nanocellulose-based materials, including films, hydrogels, foams and aerogels. Then, the fundamentals and applications of PCMs are briefly introduced. In particular, the recent progress in using nanocellulose-based materials for PCM-based LHS applications is intensively reviewed, where nanocellulose-based composite PCM slurries, capsules, fibers, films, and blocks are introduced in detail. The role of nanocellulose in preparing composite PCMs is interpreted from the perspective of its intrinsic properties. Summary and outlook are given to suggest the chances and challenges of using nanocellulose for LHS applications. This work may shed light on the innovative applications of naturally occurring polymers in sustainable energy systems and provide inspiration for the efficient utilization of sustainable thermal energy.
Nanocellulose is a promising nanomaterial for energy applications due to its natural abundance, superb properties and sustainability. Here, nanocellulose-based composite phase change materials for thermal energy storage are comprehensively reviewed.
Phase‐change materials (PCMs) offer tremendous potential to store thermal energy during reversible phase transitions for state‐of‐the‐art applications. The practicality of these materials is ...adversely restricted by volume expansion, phase segregation, and leakage problems associated with conventional solid‐liquid PCMs. Solid–solid PCMs, as promising alternatives to solid–liquid PCMs, are gaining much attention toward practical thermal‐energy storage (TES) owing to their inimitable advantages such as solid‐state processing, negligible volume change during phase transition, no contamination, and long cyclic life. Herein, the aim is to provide a holistic analysis of solid–solid PCMs suitable for thermal‐energy harvesting, storage, and utilization. The developing strategies of solid–solid PCMs are presented and then the structure–property relationship is discussed, followed by potential applications. Finally, an outlook discussion with momentous challenges and future directions is presented. Hopefully, this review will provide a guideline to the scientific community to develop high‐performance solid–solid PCMs for advanced TES applications.
An holistic analysis on the recent developments of solid‐state phase‐change materials (PCMs) for innovative thermal‐energy storage (TES) applications. The phase‐transition fundamentals of solid‐to‐solid (S–S) PCMs are introduced and discussed, developing strategies and molecular engineering design toward potential applications. The current challenges and future research directions on S–S PCMs in TES applications are also proposed.
Thermal energy storage technologies based on phase‐change materials (PCMs) have received tremendous attention in recent years. These materials are capable of reversibly storing large amounts of ...thermal energy during the isothermal phase transition and offer enormous potential in the development of state‐of‐the‐art renewable energy infrastructure. Thermal conductivity plays a vital role in regulating the thermal charging and discharging rate of PCMs and improving the heat‐utilization efficiency. The strategies for tuning the thermal conductivity of PCMs and their potential energy applications, such as thermal energy harvesting and storage, thermal management of batteries, thermal diodes, and other forms of energy utilization, are summarized systematically. Furthermore, a research perspective is given to highlight emerging research directions of engineering advanced functional PCMs for energy applications.
A comprehensive review regarding the tuning of the thermal conductivity of phase change composites for thermal energy conversion, storage, and utilization is provided, which gives an insightful understanding of the thermal energy storage and conversion processes. The aim is to stimulate potential emerging applications of phase change materials.
Polyurethane (PU) based phase change materials (PCMs) undergo the solid-solid phase transition and offer state-of-the-art thermal energy storage (TES). Nevertheless, the exploration of these PCMs in ...real-life applicable smart devices is generally hindered by the technical bottleneck of structural rigidity, low thermal storage capacity and lack of functionalities. Herein, for the first time, we systematically tuned the thermal storage capacity and flexibility of PU-based PCMs (PU-PCMs) by controlling the molecular weight of polyethylene glycol and figured out the optimum selection through the tradeoff between flexibility and thermal storage capacity. We further incorporated functionalized carbon nanotubes (CNTs) in flexible PU-PCMs to improve the thermal conductivity and solar-driven thermal conversion and storage capability. The results demonstrate that the thermal conductivity of the PU-CNT composite is improved by 2.3 times with only 5% weight content of CNTs, and the solar-thermal energy storage efficiency reaches 85.89% at 125 mW cm
−2
of irradiation power. Benefitting from the unique mechanical and thermal properties, we further explored our developed composite PCM for solar-driven thermal management of human body parts.
By tuning the molecular weight of the polyethylene glycol segment, the thermal storage capacity and flexibility of polyurethane-based phase change materials (PCMs) are engineered towards wearable applications.
Abstract
Passive daytime radiative cooling technology (DRCT) has recently gained significant attention for its ability to achieve sub‐ambient temperature without energy consumption, making it an ...attractive option for space cooling. The cooling performance can be further improved if radiative cooling materials also exhibit high thermal insulation performance. However, synthesizing radiative cooling materials that possess low thermal conductivity while maintaining mechanical durability remains a challenge. Here, a vapor exchange method is developed to prepare particles‐based poly(vinylidene fluoride‐co‐hexafluoropropylene) sponge materials for scalable and efficient daytime radiative cooling. By tailoring the particle diameter distribution, high solar reflection (94.5%), high infrared emissivity (0.956), and low thermal conductivity (0.048 W m
−1
K
−1
) are achieved, resulting in a sub‐ambient cooling of 9.8 °C under direct solar irradiation. Additionally, the sponge material exhibits good mechanical durability, sustaining deformation with a strain up to 40%, making it adaptable to diverse scenarios. A radiative cooling material with mechanical durability and thermal insulation can thus pave the way for large‐scale applications of DRCT.
Due to the unique thermal absorption and release capabilities, phase‐change materials (PCMs) are used in various industrial fields, such as photo‐thermal storage and building‐energy saving. In recent ...years, more and more research has been dedicated to applying PCMs to the medical field with substantial progress, opening new avenues for disease treatment and healthcare. The safety and reliability of PCMs may be taken into serious consider for continuous application in the medical field, while the relevant review on the related development is currently lacking. In this work, the methods for enhancing the applicability and reliability of PCMs in the medical field are systematically summarized, including microencapsulation, electrospinning technology, and porous framework encapsulation, which effectively address the issues of liquid leakage. Subsequently, the emerging advances of PCMs in medical healthcare, including medical dressings treatment, drug delivery, cold chain transport, and bio‐bone cement are summarized. By exploring and analyzing the encapsulation methods, principles as well as the emerging advances of PCMs in medical field, the challenges and perspectives promoting the applications are identified, presenting the guidelines for further development.
This work systematically summarizes the encapsulation methods for enhancing the applicability and reliability of phase change materials (PCMs) from the perspective of safety and reliability, as well as the emerging advances of PCMs in medical healthcare, clarifying the challenges and prospects for promoting the applications in the medical field, presenting the guideline for the further development.
The efficient utilization of solar energy requires advanced heat storage technology, while phase change heat storage materials cannot utilize their high-density latent heat storage performance due to ...defects such as poor light absorption and leakage. To address these deficiencies, here, shape-stabilized phase change materials (SSPCMs) of polyethylene glycol (PEG) encapsulated by polypyrrole (PPy) aerogel were prepared through chemical polymerization and physical infiltration methods. Particularly, our findings demonstrated that PPy aerogel simultaneously enhances the shape stability and improves the solar-thermal conversion efficiency of PEG. The developed SSPCMs have a melting enthalpy of 142.4 J/g and 86% solar-thermal conversion efficiency. SSPCMs can maintain a stable shape, enthalpy value, and heat release time after 100 cycles. When used as a solar-thermal conversion material in a solar thermoelectric power generation system and thermal therapy, a long-term stable output voltage of 318 mV and temperature of 40–50 °C are generated, respectively, achieving effective conversion from renewable solar energy to applicable electricity and heat energy. This work may pave an effective way for the integrated design of encapsulating materials and light-absorbing materials in SSPCMs.
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•Polypyrrole aerogel the dual function of light absorption and encapsulation.•SSPCMs have a melting enthalpy of 142.4 J/g.•SSPCMs show 86% solar-thermal conversion efficiency.•SSPCMs can keep good thermal stability after 100 cycles.
Phase change materials (PCMs) present a dual thermal management functionality through intrinsic thermal energy storage (TES) capabilities while maintaining a constant temperature. However, the ...practical application of PCMs encounters challenges, primarily stemming from their low thermal conductivity and shape-stability issues. Despite significant progress in the development of solid-solid PCMs, which offer superior shape-stability compared to their solid-liquid counterparts, they compromise TES capacity. Herein, a universal phase engineering strategy is introduced to address these challenges. The approach involves compositing solid-liquid PCM with a particulate-based conductive matrix followed by surface reaction to form a solid-solid PCM shell, resulting in a core-shell composite with enhanced thermal conductivity, high thermal storage capacity, and optimal shape-stability. The core-shell structure designed in this manner not only encapsulates the energy-rich solid-liquid PCM core but also significantly enhances TES capacity by up to 52% compared to solid-solid PCM counterparts. The phase-engineered high-performance PCMs exhibit excellent thermal management capabilities by reducing battery cell temperature by 15 °C and demonstrating durable solar-thermal-electric power generation under cloudy or no sunshine conditions. This proposed strategy holds promise for extending to other functional PCMs, offering a compelling avenue for the development of high-performance PCMs for thermal energy applications.
