High energy storage density titanium nitride-pentaerythritol solid–solid composite phase change materials for light-thermal-electric conversion

Selection of a suitable phase change material (PCM) for thermal energy storage systems is important. There are an enormous number of available PCM and hence choosing a particular PCM for a certain application is difficult. Many researchers rely on their expertise or the material available to use PCM for a specific application. The purpose of the selection of a certain PCM is to choose the best material from the commercially available PCM for a given application. An effective evaluation approach is essential to enhance the quality of the decisions. The issue of choosing a material for different applications can be managed as a multi-criteria decision-making issue. In this paper, the Analytic Hierarchy Process (AHP) method is used to select between five PCM for solar heating systems considering both the technical specification and the criteria of the materials. The selected materials have a melting temperature in the required working temperature range. Seven criteria are used in this study and these include the latent heat of fusion, thermal conductivity of the material, specific heat, density, thermal stability, cost, and corrosion. The results show that the paraffin is the best material from the selected PCM using the AHP method for this solar heating system using all known thermo-physical properties and the weights of these criteria to achieve the objective.

Solidification enhancement of PCM in a triplex-tube thermal energy storage system with nanoparticles and fins

NH4Al(SO4)2·12H2O-Na2SO4 eutectic-based phase change materials with excellent light absorbance, enhanced thermal conductivity, and high latent heat performance

Buildings use more than 40% of the total power consumed in India. Therefore, implementing energy conservation within buildings is of prime concern. Utilization of passive design parameters, such as Phase Change Material (PCM) incorporation, for energy conservation in buildings is thus a lucrative option. Incorporating PCMs within elements result in lowering of heat gain and temperature within the building. A number of simulation and experimental studies on PCM incorporated buildings, have been carried out. The advancements made in last forty years in the field of PCMs and their utilization as Thermal Energy Storage (TES) medium for buildings have been reviewed and presented in this study. This study focusses on PCM incorporation which is sensitive to its properties and climatic parameters of the location. Thus, there is a need of benchmarking the PCM for their application in buildings. Focus is on buildings in tropical hot climatic conditions, where reduction in cooling load is a challenge. This study lays emphasis on selection of appropriate PCMs based on its phase change temperature. Thermal conductivity, specific heat and latent heat are other properties which must be evaluated before PCM selection and implementation within buildings. The study also encompasses different methods of PCM incorporation being implemented across the world and have marked advantages and disadvantages of each followed by their impact in terms of energy savings.

Latent Heat Thermal Energy Accumulation Systems (LHTEAS) using Phase Change Materials (PCM) represent enormous opportunities in improving the performance of thermal energy systems. PCM have a high energy density, and these also play a vital role in energy conservation, environment protection, and sustainability. Low and high thermal range LHTEAS have been predominantly designed, analyzed, and optimized. However, no such attempts for the medium thermal range have been made. The sorting and selection of suitable candidate PCM is an uphill task because of the availability of numerous commercially available PCM with distinct thermo-physical properties. The present study aims to explore the selection of PCM using multi-criteria decision methods (MCDM). For this purpose, 91 organic PCM from the literature have been chosen for a medium temperature range of 40–120°C. The present study explored the ranking of PCM, and the findings reveal that the TOPSIS and VIKOR could have high acceptance for sorting PCM. The selection of organic PCM based on the TOPSIS and VIKOR methods are highly reliable and logical, as both produced highly consistent results with a correlation coefficient of 0.992.

Solid-solid phase change materials (SSPCMs) are potential materials for energy storage and thermal management, and improving mechanical property and heat transfer performance is the key to practical application. After modified graphene oxide (TGO) was prepared by toluene diisocyanate, a kind of super-tough, form-stable and leak-proof polyurethane composite phase change material (PU-TGO) was constructed by the two-step polymerization of isophorone diisocyanate and 1, 4-butanediol using polyethylene glycol and TGO. TGO has more uniform and stable dispersion than traditional graphene oxide, and its chemical crosslinking with polyurethane phase change materials makes the composite have better shape stability, mechanical strength, thermal conductivity and flexibility. PU-TGO has thermal conductivity and elongation at break up to 0.3072 W/(m•K) and 540%, respectively, and maintains excellent thermal stability and 72.09 J/g enthalpy after 500 thermal cycles. PU-TGO prepared by chemical crosslinks in this paper further demonstrates the great potential of phase change materials in the field of thermal management of new electronic devices.

Integrating phase change material with building envelopes is an effective way to reduce cooling or heating loads, improve indoor thermal comfort and save building energy consumption. In this paper, the composite phase change material of sodium acetate and urea is prepared and its thermal–physical properties with different mixing mass ratios are investigated through experiment and T-history method. Moreover, the heat transfer model of building envelopes with phase change material is established and different phase change material locations in external walls for thermal insulation are compared based on integrated uncomfortable degree. The results show that (1) with rising urea mass fraction, both phase change temperature and latent fusion heat (enthalpy) decline; (2) strontium sulfate is an effective nucleating additive to decrease super-cooling degree for such phase change material solidification and (3) to improve indoor thermal comfort, it is preferable to put phase change material in the middle of external walls. Furthermore, the illustrative example of an office building in Chengdu indicates that phase change material insulation can lead to time lag and decrement for indoor air temperature variations. It also indicates that after inserting such phase change material into building external wall, the highest indoor temperature can be decreased by 7℃, leading to 60% cooling energy saving in one typical summer day. This work can provide guidance for building thermal design with phase change materials. Practical application:The studied sodium acetate–urea composite phase change material has been used as energy storage and thermal insulation materials inserted in envelopes for the demonstration project of low/zero energy consumption passive buildings in China.

Investigation on the effect of physical parameters of PCMs on the exothermic properties of energy storage units of bilayer tubes

Numerical Model for Solidification and Melting of PCM Encapsulated in Spherical Shells

Intrinsic photothermal phase change materials with enhanced toughness and flexibility for thermal management in extreme environments

Energy storage potential analysis of phase change material (PCM) energy storage units based on tunnel lining ground heat exchangers

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.

Thermal energy storage (TES) using thermocline technology with phase change materials (PCM) is a promising technique for peak-shaving operation in cogeneration units. One of the disadvantages of this connotation is the use of the highly cost PCM capsules in a water tank. To circumvent this issue, a new thermocline tank connotation is proposed. The tank is packed with a mixture of solid filler pills and PCMs capsules, forming a multi-layered packed-bed system. A transient concentric-dispersion model is developed to assess the dynamic performance of a solid-PCM multi-layered packed-bed (SPMLPB) tank. The influences of the PCMs volume fraction (VF) and the charge and discharge dimensionless cutoff temperatures criterion on the dynamic performance have been investigated. The results show that the VF of PCMs influences the system's behavior, in terms of both energy storage and release. As the PCMs volume fraction increases from 10% to 40%, the amount of energy storage, energy release, and latent utilization ratio increased by 82.65%, 73.94%, and 55%, respectively, while the overall exergy efficiency drops by 6.3%. Besides, increasing both the charge and discharge cutoff temperatures criterion (STch*/STdisch*) enhances the total utilization ratio and energy recovered. When STch* increases from 0.27 to 0.7, the total utilization ratio and energy recovered increased by 63.63% and 28.67%, respectively, by maintains STdisch*=0.26.

Exploring additives for improving the reliability of zinc nitrate hexahydrate as a phase change material (PCM)

Review on Heat Transfer Enhancement of Phase Change Materials (PCMs)