Phase Change Material Technology Research Articles

Highly dispersed Ag quantum dots anchored on palmitic acid/ graphitic carbon nitride composite phase change materials for enhanced photo-thermal storage

Phase change materials (PCM) have attracted much attention in the field of thermal energy storage because of exceptional heat storage capacity, stable operating temperature, and recyclability. However, organic phase change materials, represented by palmitic acid (PA), are limited by inherent leakage problem, unsatisfactory thermal responsiveness and inefficient photo-thermal storage capacity, which severely hamper the development of PCMs technology. As a means of addressing these challenges, we developed one novel support material with 2D/0D structure for palmitic acid via thermal polymerization, specifically, in which highly dispersed Ag quantum dots (Ag QDs) was firmly anchored on graphitic carbon nitride (g-C3N4). PA was further infiltrated into the layered structure of nanoporous g-C3N4/Ag QDs to successfully synthesize novel shape-stabilized PA/g-C3N4/Ag QDs composite phase change materials (CPCM). On the one hand, benefiting from the tightly stacked porous structure of g-C3N4/Ag QDs, PA is effectively encapsulated to avoid leakage problem during the solid-liquid transition with a superior adsorption capacity up to 65%. On the other hand, the combination of g-C3N4 and Ag QDs in PA/g-C3N4/Ag QDs CPCM demonstrated a synergistic effect resulting in faster heat transfer capability and more efficient solar energy capture capability compared to pure PA, which is capable of dual utilization of heat and solar energy. The newly developed PA/g-C3N4/Ag QDs CPCM features a high melting latent heat and an appropriate phase change temperature, which are 128.35J/g and 61.92 °C, respectively. The corresponding solidification enthalpy and temperature are 121.70J/g and 60.02 °C. The photo-thermal conversion efficiency of the material is improved to 78.6%, facilitating a rapid capture and storage of solar energy. Furthermore, through the optimization of the preparation process, Ag QDs are densely anchored on the surface of g-C3N4, which retains the excellent properties of metallic silver while eliminates the metal agglomeration phenomenon after repeated utilization of CPCMs. PA/g-C3N4/Ag QDs CPCM is proved to be extremely recyclable and thermally stable after massive thermal cycles. This innovative and operational encapsulation modified method significantly optimizes the practicality of phase change materials. The obtained shape-stabilized PA/g-C3N4/Ag QDs CPCM is more versatile, and its unique comprehensive properties can provide high-quality materials for photo-thermal storage systems.

Energy, exergy and sustainability analysis of a photovoltaic-thermal solar system with nano-enhancement and thermal energy storage integration

As a result of using various energy sources such as fossil fuels, harmful gases emerge and endanger the world's future. The search for different energy sources is to diminish the dangers that may arise in the future. Renewable energy sources are also the most basic for a sustainable future. This study aims to increase the performance of photovoltaic thermal collectors (PVT), which are used to obtain thermal energy from solar energy and produce electrical energy. The novelties of this experimental work are the analysis of a combination of a solar air heater and thermal energy storage via a phase change material technology and surface modifications on absorber plates, including a nanotechnological amendment. Furthermore, the adverse impacts on the environment of the manufactured systems were taken into account with the help of such parameters as waste exergy ratio and sustainability index. Initially, PVT with a V-grooved absorber surface (V-PVT) was built. In the second stage, nano-enhanced V-grooved PVT (NE/V-PVT) was produced, in which the absorber plate was coated by graphene nanoparticles. Then, a thermal energy storage entity was mounted onto the system, and the V-grooved PVT with the thermal energy storage entity (TS/V-PVT) was developed. 40 W absorber fans were used to provide airflow in these manufactured collectors. In addition, Styrofoam insulation material was used for the collector case, and a low-cost system was designed. Simultaneous experiments for each PVT were carried out. The waste exergy ratio (WER) and the sustainability index (SI) were also considered. Based on the experimental results, thermal efficiency was calculated as 40.60%, 54.01%, and 53.90% for V-PVT, NE/V-PVT, and TS/V-PVT, respectively. Furthermore, the coefficient of performance (COP) values were obtained as 2.67 for V-PVT, 4.28 for NE/V-PVT, and 3.49 for TS/V-PVT. The findings illustrated that nano-coating and V-grooved modifications on solar collectors substantially increased the system performance.

Exploring the potential and challenges of phase change materials in future heat storage systems via computations and experiments

The current work describes computational and experimental efforts to enable new heat storage technologies. Approximately 50% of the energy consumed globally is used to generate and manage heat. This is still predominantly acquired from the combustion of fossil fuels, consequently generating just over 40% of the total global CO2 emissions. To achieve a sustainable future, there is a need for sustainable, decarbonised and dependable energy sources. Heat storage is a key technology that could help achieving this goal. Recently published work by the current authors has shown the importance of heat storage in decarbonising heating (and cooling) of buildings using phase change materials (PCMs). The black-box approach followed evaluated the energetic, cost, and environmental impacts of a novel concept PCM storage scheme with microgeneration. The results obtained showed that this system had advantages over current and future competing heating technologies. However, PCM technology remains at low technological readiness levels because of the lack of understanding of the complex heat transfer physics associated with their phase change transition. For example, understanding and characterizing the propagation of the solid-liquid front during charging and discharging in such heat storage modules will be important in predicting and optimising their performance. In the current work, computations have been performed to understand and optimise the effects of container geometry and size on the charging and discharging heat flux profiles of a simple heat storage module. Furthermore, fundamental experiments have also been implemented to identify the complex governing mechanisms of heat transfer and storage in such materials during transient operation.

Techniques for Enhancing Thermal Conductivity and Heat Transfer in Phase Change Materials in Hybrid Phase Change Material–Water Storage Tanks

In recent years, extensive research has been dedicated to enhancing energy efficiency and promoting environmental sustainability in heating and cooling systems. Among the promising solutions, phase change materials (PCM) technology stands out as a key area of exploration. This study focuses on improving the thermal performance of PCM–water hybrid tanks by investigating methods to enhance thermal conductivity and heat transfer. Through experimental testing using techniques such as copper matrices, steel twisted matrices, and copper spirals, this study demonstrates significant improvements in thermal conductivity, particularly with the use of copper matrices. The integration of a copper matrix placed in the PCM reservoir increased the heat transfer coefficient and thermal conductivity of the PCM, and thus, the total phase transformation time for solidification was reduced by 79.19% and for melting by 54.7%. Our experimental results demonstrate that the integration of a copper matrix can increase latent heat transfer from 55,677.6 J up to 125,274.6 J, marking a 125% enhancement over the experiment with pure PCM. Additionally, comparisons of the energy storage potentials for different PCMs underscore the benefits of integrating PCMs into hybrid storage tanks. These findings highlight the immense potential of PCM technology to increase energy storage efficiency in heating and cooling applications.

Advances in phase change building materials: An overview

Abstract Efficient and sustainable thermal management of buildings is critical since the building sector is considered as the largest energy contributor contributing around 40% of the total energy consumption which is responsible for about 38% of greenhouse gas emission. Utilisation of phase-change material (PCM) in building energy systems can enhance the overall energy performance of buildings, thereby making drastic reduction in greenhouse gas emissions. The major shortcoming of organic PCM is their leakage problem; however, this can be overcome through the employment of either encapsulation or shape stabilisation technology. Numerous papers have prepared unlimited number of form stable PCMs for various applications ranging from textiles to thermal energy storage (TES); however, the factors to consider when selecting PCM for an intended application are not clear and the influence of synthesis techniques and processing parameters on the performance of stabilised PCM is yet to be understood. Also, majority of the publications have focused mainly on the encapsulation of paraffins for TES by employing different encapsulation techniques. Therefore, selecting a suitable technique for the synthesis of form stable PCM is the most challenging. This review aims at providing a comprehensive database addressing these issues, focusing mainly on PCMs, processing techniques, performance of encapsulated and composite PCMs, and phase change building materials prepared in previous studies, since this is the most critical information required to widen the potential usage of PCM technology in building applications. A concise summary of environmentally friendly poly(ethylene glycol)-based composite PCMs is also included.

Advancements in Phase Change Materials: A Path to Sustainable Energy Solutions in China

With the rapid development of China, the country's demand for energy has significantly increased. According to the "World Energy Outlook 2020," China's annual average growth rate of primary energy consumption is 1.9%, and it is predicted that China's energy consumption will account for over 20% of global energy consumption by 2050. In the energy budget, 90% is allocated to thermal energy conversion, transmission, and storage. Facing an impending energy crisis, enhancing energy production while minimizing energy loss has become a matter of widespread concern. Phase Change Materials (PCMs), also called phase change energy storage materials, have garnered attention as a novel energy-efficient and environmentally friendly material. PCMs refer to substances that undergo a change in state and provide latent heat without changing their temperature. Phase change thermal storage materials utilize phase transitions during heat exchange processes to store energy by means of these phase changes. Compared to chemical energy storage materials, PCMs offer high thermal efficiency and energy storage density, maintain constant temperature, and are more easily controllable. They hold great potential as a promising material in the field of thermal energy storage and have been widely applied in areas such as solar energy, lithium batteries, building insulation, and medical applications. This article offers a comprehensive overview of the principles and classification of Phase Change Material (PCM), including organic PCM, inorganic PCM, and composite PCM. It discusses their applications in solar thermal energy storage, cooling of photovoltaic panels, building materials, and industrial waste heat recovery. The article also highlights China's research and development efforts in these areas, emphasizing the country's significant contributions to advancing PCM technology.

Phase-Change Material Thermal Energy Storage for the Smart Retrofitting of Existing Buildings

This article presents the use of phase-change material (PCM) thermal storage within the Horizon 2020 HEART project (Holistic Energy and Architectural Retrofit Toolkit), aimed at decarbonising the European building sector through the retrofitting of existing structures into energy-efficient smart buildings. These buildings not only reduce energy consumption, but also incorporate advanced technologies for harnessing green energy, thereby promoting environmental sustainability. The HEART project employs state-of-the-art technologies for electricity production/dispatching and heat generation/storage, managed by a cloud-based platform for the real-time monitoring of parameters and optimising energy utilisation, enabling users to control their environmental comfort. The article provides a detailed examination of one of the project’s demonstration sites in Italy, focusing on various components such as heat pumps, photovoltaic systems (PV), controllers, and particularly emphasising the significance of storage tanks. The study involved the measurement and analysis of three heat storage tanks, each with a total volume of 3000 L. These tanks utilised PCM modules for latent heat storage, significantly enhancing overall heat accumulation. Water served as the heat transfer fluid within the tanks. Through meticulous calculations, the article quantifies the accumulated heat and presents a comparative evaluation between PCM-based storage tanks and conventional water tanks, showcasing the advantages of PCM technology in terms of increased heat retention and efficiency.

Thermal performance enhancement methods of phase change materials for thermal energy storage systems – A review

Phase Change Materials (PCMs) have emerged as a promising solution for efficient thermal energy storage and utilization in various applications. This research paper presents a comprehensive overview of PCM technology, including its fundamental working principles, classification and different shapes of container used for PCM storage. The study investigates the optimal melting temperature of PCMs and explores various Thermal Energy Storage (TES) methods and their types. This paper discusses novel approaches to enhance the thermal performance of PCMs, such as incorporating high-conductivity materials, Nano-encapsulation, Composite formation, and Shape stabilization. These innovative techniques have shown great potential in enhancing efficiency of PCM-based TES systems. The information presented in this paper is an in-depth analysis of research papers published over the last five years (2019 to 2023). It is a valuable source for researchers seeking to stay current with the modern advancements in PCM technology and its applications. This research contributes to advancing sustainable and efficient thermal energy utilization by promoting a deeper understanding of PCM's capabilities and challenges.

Hydrogen-based microgrid: Development of medium level controls in a multilevel algorithm framework

In renewable-based microgrids, intermittency caused by some energy sources highlights the important role of energy storage systems. Nowadays, hydrogen and thermal energy storage are expected to play key roles in grid-scale applications, for facilitating effective penetration of clean energy sources. This paper, through a multilevel control framework for the energy management of a renewable and reversible solid oxide based microgrid, develops medium level controls accounting for the dynamic behaviour of storage systems. The storage systems considered are a hydrogen storage tank and a thermal energy storage based on phase change material technology. In particular, the proposed algorithm is helpful in the microgrid design phase as well as for clearly assessing high-level energy management strategies, since dynamic and transient behaviours of tanks during both charging and discharging phases are validated. In this way, top-level energy management strategies can be further refined and optimized in addition to a techno-economic design being pursued, primarily through shrinking the initial sizes of storages and thereby achieving significantly lower initial capital costs. For the analyzed microgrid, its feasibility is demonstrated by reducing by as much as 40% the size of the hydrogen tank and by up to 20% the energy capacity of the thermal storage. Finally, the proposed medium level control in a multilevel algorithm framework for a hydrogen-based microgrid is also seen to be fruitful for avoiding waste energy, which can be beneficial against the background of distributed energy systems acting in virtual power plants.

Heat transfer characteristics of triple-tube latent heat storage system placed horizontally and vertically

Phase change heat storage technology can realize the utilization of thermal energy across time and space, which is of great significance for solving the problem of mismatch between supply and demand of renewable energy and promoting the energy structure adjustment of our country. However, the low thermal conductivity of phase change materials (PCM) severely limits the application and development of PCM technology. Compared with the traditional two-tube phase change heat storage system, the three-tube latent heat storage system (TTLHSS) has the advantages of large heat transfer area and good heat transfer uniformity. However, there is a lack of comparative research on the heat storage and release performance of the triple tube phase change heat storage system placed horizontally and vertically. Based on the above, this paper studies the heat transfer characteristics of the triple tube phase change heat storage system placed horizontally and vertically, and compares the influence of the tube length on the heat storage and release performance. The coagulation/melting model and Boussinesq model of Fluent software were used to calculate the coagulation and melting process of lauric acid with the same structural parameters placed horizontally and vertically. The results show that when the tube length is 250 mm, the solidification and melting time of lauric acid in the case of horizontal placement is less than that in the case of vertical placement, decreasing by 8 % and 45.9 %, respectively. In addition, it is found that the natural convection has little influence on the axial heat transfer, so the tube length has little influence on the horizontally placed TTLHSS, which can be simplified to a two-dimensional structure for calculation. Due to the phenomenon of temperature stratification in the heat storage process in the case of vertical placement, the heat storage performance will decrease significantly with the increase of tube length, so the tube length has a certain impact on the heat storage and release performance of the triple tube phase change heat storage system placed vertically.

Revolutionizing the Building Envelope: A Comprehensive Scientific Review of Innovative Technologies for Reduced Emissions

The energy and thermal performance of buildings is heavily dependent on the building envelope. As such, innovative environmental building envelope technologies are being developed to improve building energy efficiency and reduce greenhouse gas emissions. This paper provides a comprehensive review of the latest environmental building envelope technologies, such as phase-change materials (PCM), aerogel, and active and adaptive systems, to offer an overview of the current state-of-the-art in the field and identify future research directions. PCM technology has the potential to improve thermal comfort and reduce energy consumption by reducing peak heating and cooling loads. Paraffin wax is the most reliable PCM for use in building envelopes, and studies have shown that it can reduce heating and cooling energy consumption by up to 20 % compared to traditional insulation materials. Aerogel is a low-density and highly insulating material that has been shown to enhance thermal insulation and reduce heat transfer in buildings. Silica aerogel can provide thermal performance up to 2–4 times higher than traditional insulation materials, resulting in significant energy savings of up to 50 %. Active and adaptive systems, such as smart windows and dynamic insulation, allow for real-time control of building envelope performance, further improving energy efficiency and indoor comfort. Smart windows can lead to energy savings of up to 20–30 % compared to traditional windows, while dynamic insulation systems can provide energy savings of up to 50 % compared to traditional insulation materials. The review assesses various adaptive facade solutions based on their suitability for diverse climate zones, versatility in application, global availability of materials used, and energy efficiency. Despite the challenges and limitations of these technologies, including high costs, lack of widespread adoption, and limited understanding of long-term performance, the authors conclude that continued development and implementation of these technologies have the potential to make significant contributions to improving building energy efficiency and reducing greenhouse gas emissions. This review provides a valuable resource for researchers and practitioners working in the field of building envelopes and offers insights into the future research directions necessary to further advance the field.

Enhancing efficiency of PVT systems with finned PCM technology

An increase in solar panel temperature reduces panel electrical efficiency, necessitating efficient active and passive cooling methods. This study proposes the introduction of Phase Change Material (PCM) on the backside of the solar panel, along with extended fins. The experimental investigation focuses on utilizing extended surfaces known as Thermal Conductivity Enhancers (TCE) in the PV-PCM (Photo Voltaic - Phase Change Material) module. Two independent aluminum fin designs are considered to enhance the thermal conductivity (k) of the PCM, analyzing the influence of the surface contact area and material volume fraction on the PV surface temperature during the charging period of the Production Validation Test-Pulse Code Modulation (PVT-PCM) panel. The experimental results demonstrate that an array of longitudinal and lateral fins with an optimal thickness of 3 mm maintains a lower temperature gradient throughout the process, significantly reducing the surface temperature of the PV panel. Numerical simulations using ANSYS Fluent were conducted for both the lateral- and cross-fin configurations, showing good agreement with the observed experimental data. This study aims tofill this research gap by optimizing PV panel cooling through the selection ofthe fin geometry, size, shape, and PCM.

Chalcogenide Phase-Change Material Germanium Telluride for Radio-Frequency Applications: An overview

Chalcogenide phase-change materials (PCMs) have been widely used in optical storage media and nonvolatile memory devices applications. Over the past several years, there has been interest in exploiting PCM technology, especially germanium telluride (GeTe) and its alloys, for radio-frequency (RF) applications. The principle of operation of PCM-based RF devices is based on the ability of the material to transform from a high-resistivity (amorphous phase) to low-resistivity state (crystalline phase) and vice versa, with the application of a short, thermal pulse. Actuation pulses are applied to microheaters embedded with the PCM junction to switch between the two states. The PCM switch can exhibit more than five orders of resistance change between the two states. PCM-based RF switches are expected to bridge the gap between semiconductor switches and microelectromechanical systems (MEMS) switches as they combine the low insertion loss performance of MEMS technology and the small size and reliability performance of semiconductor technology. In addition to miniaturization, GeTe-based switches offer unique latching functionality and ease of monolithic integration with other RF circuits. This article presents an overview of PCM technology and its applications to RF circuits. A brief history of the technology is presented first, followed by a discussion of the basic characteristics of PCMs. The steps of a fabrication process of PCM RF devices are illustrated. A description of RF-PCM switch is presented in detail along with a comparison between RF performance of PCM switches and other existing commercial switches. As examples of application of the PCM technology to other RF circuits, the article concludes by presenting a crossbar switch matrix, phase shifter, and variable attenuator, realized using the PCM technology.

Does socket liner material affect clinical outcomes in lower limb prosthesis users? Insights from a randomized control trial.

Among the noted disadvantages of prosthesis suspension by flexible liner is the increased rate of perspiration within the socket, which has the potential to cause discomfort, suspension issues, and tissue damage. In recent years, phase change material technology has been adopted for the use in prosthesis liners. These promise to improve temperature control and, consequently, reduce sweating. Previous work has demonstrated that this approach is effective in slowing the temperature increase at the limb-socket interface, but it was not clear how this would translate to clinical outcomes. This study had the aim to compare conventional and phase change material liners regarding prosthesis utilization, physical performance, and patient-reported outcome measures. A randomized double-blind cross-over study design with 6-month intervention periods was used. Of the 42 enrolled participants, only 50% completed the protocol. The high attrition was in large part because of the COVID-19 pandemic that started disrupting daily life and thereby the data collection midway through the study period. The findings indicate that the temperature control liners were, by trend, associated with better prosthesis utilization. The found effects did not reach the level of statistical significance, which is likely a result of the unduly reduced sample size.

An Updated Review on Low-Temperature Nanocomposites with a Special Focus on Thermal Management in Buildings

Buildings contribute to 33% of total global energy consumption, which corresponds to 38% of greenhouse gas emissions. Enhancing building’s energy efficiency remains predominant in mitigating global warming. Advancements in thermal energy storage (TES) techniques using phase change material (PCM) have gained much attention among researchers, primarily to minimize energy consumption and to promote the use of renewable energy sources. PCM technology stays as the most promising technology for developing high-performance and energy-efficient buildings. The major drawback of PCM is its poor thermal conductivity which limits its potential use which could be resolved by dispersing conductive nanofillers. The acquired database on synthesis routes, properties, and performance of nano-dispersed phase change materials (NDPCMs) with various techniques presented in the paper should deliver useful information in the production of NDPCMs with desirable characteristics mainly for building construction applications. An outline of contemporary developments and use of NDPCMs as TES medium is delivered. Finally, a brief discussion on challenges and the outlook was also made. In-depth research is needed to explore the fundamental mechanisms behind the enhanced thermal conductivity of NDPCM with nanofillers dispersion and also a thorough investigation on how these mechanisms drive improvement in building performance.

PCM Thermal Storage Technology and its Military Applications: A Review

Abstract: Phase Change Materials (PCM) are the most promising and budding technology in the field of Thermal Energy Storage (TES) and thermal comfort in buildings. PCMs are being extensively used and researched across the world for the improvement of thermal performance of buildings by smoothening temperature peaks as well as act as a power-saving tool in buildings where heating or cooling is required. PCMs can absorb and release heat or cold energy when it undergoes a phase change from solid to liquid and vice versa. This process takes place at a constant temperature absorbing a huge amount of energy in form of latent heat of fusion or vaporization in comparison to sensible heat which is absorbed with an increase of temperature. India’s frontiers stretch across a few of the world’s extreme terrains having extreme climatic conditions varying from extremely hot climates on western borders to extremely cold climates on its northern extremities. The unique characteristic of PCM based latent heat storage system can be utilized in lightweight prefabricated PUF insulated shelters used by security forces, to increase its thermal resistance or store excess heat from intermittent renewable sources during daytime for use during the night, thereby helping in maintaining a comfortable temperature inside the shelters. The PCMs characteristic of absorbing and releasing heat at a constant temperature can be effectively utilized in various other applications where thermal management or temperature control is of importance. It can also help in enhancing the mission reliability of its vehicles, equipment, plant, and electronic instruments when deployed in areas having extreme temperatures. In the present work, a broad study has been conducted based on recent progress and research across the world on PCM technology and its probable applications in the defense sector. The aim is to highlight the potential of PCMs to be utilized for the enhancement of the performance of manpower and critical equipment deployed under extreme climatic conditions encountered by the Security forces. Keywords: Phase Change Material, Thermal Energy Storage, Latent Heat Storage, Military Applications, Security forces, Indian Armed forces.

Holistic Integrated Process Solutions for Patterning Phase Change Memory Devices

Phase change materials (PCM) have emerged as the leading candidate for next generation non-volatile storage class memory as demonstrated by the commercialization of 3D Cross Point memory. More recently, PCM memories have been explored for non-von Neumann system architectures with potential applications in neuromorphic computing. To accelerate the widespread adoption of PCM technology, better understanding of the unit processes and its interactions is needed to cost effectively produce high fidelity PCM devices.Challenges in creating cross point PCM architectures are significantly different from more dominant technologies such as DRAM and 3DNAND. From a device perspective, the PCM composition is sensitive to crystallization temperature, which translates to potentially large changes in the switching resistance for small changes in composition. From a material perspective, phase change chalcogenides readily etch in various plasma etch chemistries with the many etch chemistries exhibiting bulk composition changes. Furthermore, slight changes in the PCM composition can be removed by wet clean. In this regard, one of the main process challenges is to not etch chalcogenides laterally in order to maximizing the device volume. Finally, from a structural perspective, PCM are relatively soft with Young’s modulus that can be 3x smaller than materials found in DRAM/3DNAND stacks (e.g. Si, SiOx). Soft chalcogenides can lead to increased line bending, especially when the chalcogenide is at the bottom of the stack. As a result, post wet clean pattern collapse and line bending from film stress can be challenging to manage.To meet the material and structural challenges, we developed an integrated system combining dry etch, wet clean, and deposition process modules. Comprehensive understanding of each process module as well as the interactions of different process modules has been obtained. We will present some holistic process solutions combining dry etch, wet clean, and deposition to deliver collapse free, high fidelity PCM structures.

Phase change materials for building construction: An overview of nano-/micro-encapsulation

Abstract Buildings contribute to 40% of total global energy consumption, which is responsible to 38% of greenhouse gas emissions. It is critical to enhance the energy efficiency of buildings to mitigate global warming. In the last decade, advances in thermal energy storage (TES) techniques using phase change material (PCM) have gained much attention among researchers, mainly to reduce energy consumption and to promote the use of renewable energy sources such as solar energy. PCM technology is one of the most promising technologies available for the development of high performance and energy-efficient buildings and, therefore, considered as one of the most effective and on-going fields of research. The main limitation of PCM is its leakage problem which limits its potential use in building construction and other applications such as TES and textiles, which can be overcome by employing nano-/micro-encapsulation technologies. This paper comprehensively overviews the nano-/micro-encapsulation technologies, which are mainly classified into three categories including physical, physiochemical and chemical methods, and the properties of microcapsules prepared. Among all encapsulation technologies available, the chemical method is commonly used since it offers the best technological approach in terms of encapsulation efficiency and better structural integrity of core material. There is a need to develop a method for the synthesis of nano-encapsulated PCMs to achieve enhanced structural stability and better fracture resistance and, thus, longer service life. The accumulated database of properties/performance of PCMs and synthesised nano-/micro-capsules from various techniques presented in the paper should serve as the most useful information for the production of nano-/micro-capsules with desirable characteristics for building construction application and further innovation of PCM technology.

Performance study of solar photovoltaic cold storage system using phase change materials

Phase change material technology has great potential in energy storage and cost-saving in the applications of cold thermal energy storage. This study presents the performance and evaluation of phase change material (PCM) in the Prototype Solar Cold Storage (PSCS) system. Five different experiments were conducted to measure the performance of the PSCS system. The experiment results showed that 16 kg of PCM charged in 75–90 min and able to maintain the temperature within the setpoint about an average of 150 min. However, PCM is a promising material for cold thermal energy storage applications. Also, Solar Photovoltaic (PV) integrated with the cold storage system and the tested results indicate the grid energy replaced by solar and PCM about 16% of the total power consumption. Besides, the proposed technologies are suitable for solar PV generation & reduction of greenhouse gas emissions.

Performance evaluation of latent heat TES system-case study: Dimensions improvements of annular fins exchanger

Thermal Energy Storage (TES) is an important challenge for the development and implementation of Concentrated Solar Power (CSP) plants. The heat can be stored in a sensible, thermochemical or latent form. Recently, the latent heat thermal energy storage (LHTES) kind has gained the most of research interest as it has the advantage of increasing the energy density of the current commercial TES systems through the use of a Phase Change Materials (PCM). However, the main limitation of PCMs technology is the low thermal conductivity, which affects the system performances and lead to significant energy losses. In this sense, a good container design can impact positively the system performances. For that sake, several designs have been proposed to overcome the decreasing heat transfer rate. For this purpose, this study propose many enhancements and improvements of the fins method based on the integration of PCM in an exchanger with annular fins. The main objective of this paper is to study the impact of finned exchangers on the total flow transferred and also on the height of these annular fins. Finally, the physical model describing the thermal behavior of the studied system is developed and simulated after 80 min of charging process.