Phase Change Material Heat Storage Research Articles

Kinetics study on inhibiting battery thermal runaway using an inorganic phase change material with a super high thermochemical storage capacity

Lithium-ion batteries are susceptible to fires and explosions due to thermal runaway, a serious safety hazard. This study explores the potential of using hydrated inorganic salt (TCM40) composite phase change materials to prevent thermal runaway in battery packs. TCM40 composites stand out due to their exceptional thermochemical heat storage capacity, which allows them to effectively absorb excess heat during runaway events. The research investigates how thermal conductivity, thermal storage capacity, and cell spacing influence the propagation of thermal runaway. The findings demonstrate that TCM40 composites, with a thermal storage density exceeding 1000 kJ/kg, are significantly more effective in preventing thermal runaway compared to traditional latent heat storage phase change materials with lower capacities. To gain a comprehensive understanding of thermal runaway mitigation, a combined thermal management model was developed. This model integrates a battery thermal runaway model with a kinetic model describing the decomposition of TCM40 composites. The analysis reveals that the high heat absorption capability of TCM40 composites minimizes heat transfer to neighboring cells during thermal runaway. Furthermore, the model provides valuable insights into the synergistic effects of thermal conductivity and heat storage capacity on runaway propagation. This knowledge can be directly applied to design safer battery packs, even for compact configurations where cell spacing is less than 2 mm. This study offers significant advancements in both thermal protection materials and design strategies for lithium-ion battery packs. These advancements have the potential to significantly improve battery system safety and minimize the risk of explosions.

Experimental investigation on the thermal enhancement of spherical macro-encapsulated phase change material assisted soil heat accumulators

Reserved cavities during construction have the potential to serve as the space to efficiently harness shallow geothermal energy resources in light of the underground spaces' rapid expansion. Earth-air heat exchanger technology is an effective way among all the technologies. However, as the heat storage capacity of the surrounding soil gradually diminishes due to the long-term operation of the system, it is recommended to incorporate phase change materials (PCMs) with a stabilized heat storage capacity to improve the overall thermal performance of the system. This research specifically recommends back-filling macro-encapsulated PCMs measuring 15–25 mm in order to prevent backfill contamination caused by PCM leakage. The shells and cores of the PCMs are polypropylene spheres and n-heptadecane. Different volume proportions of macro-encapsulated PCMs are used in the design of modified soil accumulators. 27 groups of orthogonal array experimental tables were made using the Taguchi method to test the improved heat accumulator's performance with different heating sources. According to the results, adding PCMs causes the peak temperature to change and increases overall energy storage by 7.2 %. The most significant factor is the soil moisture content, which accounts for 62.47 % of the overall impact of the PCM's heat storage ratio and total heat storage capacity. With a contribution of 20.41 %, the PCM ratio is ranked second. Furthermore, optimization options for the primary parameters that impact the total heat storage and heat storage ratio of the PCM are offered. This paper offers references for the potential use of the PCM-assisted EAHE system design in real-world engineering applications.

Preparation of Al[sbnd]Si microcapsules with high latent heat and durability via control of shell thickness

Microencapsulation of the AlSi alloy is an effective approach to overcome the challenges of corrosion and oxidation during high temperature operational service when used as phase change heat storage material. Research to date has shown that the prepared microcapsules was not able retain the high latent heat of AlSi alloy and achieve excellent thermal cycling performance at the same time. In this work, AlSi alloy microcapsules with adjustable shell thickness were successfully prepared through hydrothermal reaction, in situ polymerization and heat treatment at different oxygen contents. The phase composition and microstructure of the microcapsules were characterized in detail by XRD and electron microscopy. The thermal performances were tested through thermal cycling and thermal analysis. The results demonstrated that the outer protective shell layer of microcapsules was composed of dense α-Al2O3 and the thickness was adjustable from 372 to 1504 nm by controlling the oxygen content during heat treatment. Meanwhile, the regulation mechanism of shell thickness was analyzed. According to thermal analysis, the latent heat of microcapsules could achieve 450 J·g−1, and the latent heat retention was 100 % after 5000 thermal cycles from 500 °C to 650 °C. This work provides new method of adjusting the shell thickness of AlSi microcapsules to achieve an ultra-high thermal performance in terms of latent heat and retention, which promotes the development of applications for metal-based heat storage materials.

Preparation and characterization of Al-12Si/ceramic composite phase change heat storage material

Preparation and characterization of Al-12Si/ceramic composite phase change heat storage material

Study on the Influence of Phase Change Process on the Desorption Characteristics of Gas-Containing Anthracite in Phase Change Heat Storage Materials

Study on the Influence of Phase Change Process on the Desorption Characteristics of Gas-Containing Anthracite in Phase Change Heat Storage Materials

Thermo-economic assessments on building heating by a sewage source heat pump coupled with heat storage system

To enhance the economic feasibility of building heating systems, phase change heat storage materials are often utilized to utilize renewable energy and address system peak loads. This article presents an innovative method of integrating a sewage source heat pump with a heat storage device. Upon an industrial building in Xilinhot as a case study, numerical models for the heat accumulator coupled with the energy consumption of buildings are established, taking into account dynamic hourly loads and meteorological conditions. Through a comprehensive analysis, the thermophysical properties of the heat accumulator as well as the economic implications of the multi-energy complementary heating system are investigated. Results demonstrate that the complete melting time for a 95 % filling rate is significantly reduced, 87.11 % shorter than that of pure phase change material, achieving the highest heat storage efficiency. Furthermore, the phase change storage device with a 75 % filling rate had the shortest investment payback period, requiring only 6 years. These findings have significant implications for guiding green renovation projects in building heating systems.

Effect of arrangement patterns of spheres encapsulating phase change material in packed beds on thermal performance

The NaNO3-KNO3 salt has the disadvantage of poor heat transfer capacity and low heat transfer efficiency in single-tank heat storage systems. However, molten salt can be used as phase change materials (PCM) and encapsulated with highly conductive sphere-shaped metals as PCM spheres. Arranging these spheres can appropriately change the situation. In this study, a heat storage system of a multilayer packed bed of PCM spheres consisting of NaNO3-KNO3 salt and type 316 stainless steel sphere shell was designed. This system's heat transfer and heat storage performance were also investigated using CFD simulation. For the same sphere diameter, the heat storage efficiency of hexagonal close packing (HCP) was 1.1 times that of cubic close packing (CCP). With the same porosity, the heat charging efficiency for the case using the 47.5 mm sphere diameter was the highest, at 99.3 %. When the number of layers of spheres was increased from 3 to 7, the heat flux through the sphere wall and the heat storage density of PCM spheres decreased from 40.8 kW and 67.3 × 105 kJ/m3 to 35.7 kW and 59.2 × 105 kJ/m3, respectively. Therefore, the heat charging efficiency of HCP was better than that of CCP. Reducing sphere size could shorten the heat transfer time and improve the heat storage efficiency. These numerical simulation results are consistent with the commonly known fact that the volumetric heat transfer intensity in the porous media is proportional to the reciprocal particle size since the smaller the particle size, the larger the contact area between the packing and the fluid. The conclusion drawn from the present findings provides an idea for designing a PCM heat storage system with high temperature and high efficiency of molten salt. The idea could also be used as a reference for the optimal design of a packed bed reactor.

Preparation of phase change Heat storage wood with in-situ generation of thermal conductive particles to improve photothermal conversion efficiency

Wood has been developed with phase change heat storage function using balsa as a natural packaging material, and PEG was employed as a material for phase change heat storage (PCHS). Moreover, the thermal conductivity efficiency of the wood was be improved by in-situ synthesizing Fe3O4 in wood. The prepared PCHS wood was characterized by high solidification and melting enthalpies. The temperature of phase change ranged from 21.47 °C to 35.30 °C, consistent with the temperature range that makes humans comfortable in their body. The in-situ generation of Fe3O4 not only improves the PCHS wood's thermal conductivity efficiency, but also forms a 3D network structure with PCHS materials, thereby improving the dimensional stability. Comparing with original wood, PCHS wood shows good temperature regulation function, which can quickly convert light energy into internal energy and has a longer period of thermal radiation at low temperatures. The generated PCHS wood shows a promising application as indoor temperature regulating materials to promote building energy conservation.

A study on novel dual-functional photothermal material for high-efficient solar energy harvesting and storage

The solar-heat storage efficiency of devices based on phase change materials (PCMs) is limited due to the light absorption and internal heat transfer within the PCMs, unclear thermal conductivity-enhancement mechanism within nanocomposite PCMs, and uncontrollable photothermal-interface modulation. Therefore, a novel controllable strategy was proposed in this study to fabricate dual-functional photothermal storage three-dimensional (3D) phase change blocks (PCBs) with higher thermal conductivity (27.98 W/m·K) and spectral absorption (98.03 %) compared to those of most previously reported PCM-based devices. The as-synthesized PCBs contained millimeter-sized graphite plates with horizontal Van der Waals bonds and oriented micro/nanoscale graphite nanosheets. The structural properties of thin PCM layers between the PCB sheets have synergistically reduced the internal interfacial thermal resistance of the PCBs. Laser-controllable induction was used to fabricate integrated biomimetic-forest 3D optical absorbers on the high thermal conductivity interface of the PCBs, which significantly reduced the thermal resistance of the optical-thermal interface. The resulting 3D-PCBs, integrated with thermoelectric generators, powered portable electronic devices, expanding the applications of traditional PCM heat-storage devices. Therefore, this study will guide the future design of high-performance solar-thermal storage PCMs with a wide range of practical applications.

Thermal performance of an active casing pipe macro-encapsulated PCM wall for space cooling and heating of residential building in hot summer and cold winter region in China

Phase change material (PCM) wall is expected to match the building type and its climate region effectively. In order to meet the space cooling and heating of residential buildings in hot summer and cold winter regions in China, a new active casing pipe macro-encapsulated PCM wall is proposed, in which the cold storage and heat storage PCMs are sealed between the inner pipe and outer pipe with no leakage. To obtain the optimal structure parameters and better thermal performance of the PCM wall, the mathematical model of the PCM wall is established and validated by experiment, and the effects of PCM filling pattern, structural parameter of casing pipe, water temperature in inner pipe and indoor setting temperature are simulated and analyzed. The results show that the optimal PCM filling pattern is to fill the cold storage PCM and heat storage PCM in the gap between the inner pipe and outer pipe separately; the optimal PCM filling thickness is 13 mm; the optimal structural parameters are inner pipe diameter of 20 mm and casing pipe centre spacing of 61 mm. The water temperature in the inner pipe and PCM energy storage/release time reasonably match the indoor setting temperature. Under the optimal operating conditions, the average PCM wall surface temperatures of 20.5 and 26.8 ℃ and the PCM wall surface heat fluxes of 45.9 and 57.2 W/m2 can be obtained in summer and winter conditions, respectively. The research provides an optimized casing pipe macro-encapsulated PCM wall system that can reliably and efficiently meet both the space heating and cooling demands of residential buildings in hot summer and cold winter regions in China.

Study on thermal storage performance of a novel conical spiral tube heat storage system

Due to the structural advantage of the conical spiral tube, which is narrow at the top and wide at the bottom, it helps to improve the thermal response rate of the heat storage system. Therefore, this study proposes a novel conical spiral tube heat storage system. The software Fluent is used to conduct three-dimensional unsteady state calculations and investigate the effects of the conical ratio, taper, and length-to-diameter ratio on the phase change material (PCM) thermal storage performance. The results indicate that when the conical ratio is increased from 1.0 to 3.0, the PCM heat storage capacity is reduced by 1.05%, the melting time is shortened by 17.60%, the average heat storage rate is increased by 20.10%, and the heat storage efficiency is reduced by 0.10%. Continuing to increase the conical ratio, the optimization of the performance is not obvious. Subsequently, a conical ratio of 3.0 heat storage tank is used as the reference unit. When the tank taper is increased from 0 to 0.22 and the length-to-diameter ratio is increased from 1.44 to 1.85, the melting time is shortened by 7.59% and 32.62 %, the heat storage capacity is reduced by 3.45% and 9.24%, the average heat storage rate is increased by 4.47% and 34.69%, and the heat storage efficiency is reduced by 0.02% and increased by 7.99%, respectively. Continuing to increase the taper from 0.22 to 0.32 does not result in an effective improvement of the performance. This study is a good guide for the optimization of the thermal storage performance of spiral tube heat storage systems and the efficient use of solar energy.

Microencapsulation of Al-Si-Fe alloys for high-temperature thermal storage with excellent thermal cycling performance

Metal-based phase change heat storage materials have become a potent candidate to regulate supply and demand of thermal energy due to their high conductivity, latent heat and stability. With the development of high-efficiency energy storage systems, materials with higher phase change temperatures are in demand urgently for more effective energy storage, which had not been achieved. Herein, the industrial Al-Si-Fe alloy with phase change temperature of 869 °C was chosen as heat storage material in this research. Furthermore, to prevent the alloy from the inherent problems such as liquid leakage, oxidation and corrosion at high temperature, a new and simple strategy was developed to micro-capsulate the alloy. The prepared process of microcapsules involved two steps: pre-coated of aluminum hydroxide along with hydrothermal carbon and heat treatment in nitrogen atmosphere. The composition, morphology, and thermal performance of the microcapsules were characterized by XRD, SEM, TEM, and TG-DSC. The results indicated the shell below 1 μm was composed of α-Al2O3 strengthened by network AlN fibers formed through the V-S mechanism. The latent heat of microcapsules reached 187.6 J·g−1 which was 82.9 % relative to raw material. Moreover, the total latent heat of the microcapsules did not change much after 300 cycles between 500 and 900 °C, although the phase transition behavior was altered. Overall, this research provides a novel idea for the encapsulation technology and the application of thermal energy storage materials from preparation and structure, which is conducive to promote the application of high-temperature phase change materials.

Thermal management of honeycomb heat sink filled with phase change material for smart lighting applications

Recently, thermal management of LEDs lamps has become increasingly essential due to the widespread integration of LEDs in smart lighting applications. In this work, we focus on the thermal analysis of convective heat transfer using a honeycomb heat sink designed for LEDs lamp cooling. Three different heat sink geometries were examined: an aluminum-filled honeycomb radiator, a hollow honeycomb radiator, and a hollow honeycomb radiator incorporating a phase change material (PCM) layer. The results obtained from numerical simulations using COMSOL Multiphysics® showed that the third heat sink geometry, when employed in short-duration lighting applications, led to a 25% reduction in temperature for a 20W power lamp. We also determined the optimal operational time, during which the temperature drop is maximum. Moreover, we observed that the integration of a PCM-filled honeycomb radiator in cyclic lighting applications (involving on/off cycles and high/low power settings) significantly mitigates temperature rise in the lamp by leveraging the PCM's heat storage capacity. This approach effectively prevents thermal shocks, ensures prolonged LEDs performance, and contributes to energy savings in the lighting sector. By addressing the thermal management challenges associated with LEDs lamps through innovative heat sink designs and the utilization of PCM, our research offers valuable insights for enhancing the overall performance and efficiency of LED lighting systems.

Thermal performance of solar flat plate collector using energy storage phase change materials

AbstractThe present study has been carried out to improve the overall efficiency of a conventional flat plate solar collector (FPSC) using two different heat storage phase change materials (PCMs). Two grades of paraffin wax—Paraffin‐P116 (PCM‐1) and Paraffin‐5838 (PCM‐2) as PCM are selected for the analysis based on their high heat fusion rate, low thermal conductivity, and suitable phase transition temperature. The present code has been validated with experimental results and it showed a maximum error of 6.43% in predicting the water outlet temperature. Absorber plate temperature, useful heat transfer rate, water outlet temperature and efficiencies are estimated to improve the performance of FPSC with and without PCM for various flow rates (15 lph and 30 lph) with two different weights of PCM (9 kg and 14 kg) for three different locations in India, [Chennai (13.0827° N, 80.2707° E), Bengaluru (12.9716° N, 77.5946° E), and Delhi (28.7041° N, 77.1025° E)]. The maximum increment in the efficiency of FPSC with the use of PCM‐1 is 19.59% and with the use of PCM‐2 is 16.53%. Using 14 kg of PCM‐1 with the conventional FPSC at water inlet flow rate of 15 lph increases the overall thermal efficiency up to 19.59% compared with conventional FPSC. The maximum increase in the percentage of efficiency with PCM‐1 from conventional FPSC for different cases of 15 lph‐09 kg is 16.34%, 15 lph‐14 kg is 19.59%, 30 lph‐09 kg is 14.57% and 30 lph‐14 kg is 18.45%. From the present study, it can be concluded that the overall efficiency of FPSC is increased with the use of 14 kg of PCM‐1 with conventional FPSC at the inlet water flow rate of 15 lph.

Experimental study of breathable and heterogeneous phase change material (B&H-PCM) wall for all-season thermal performance enhancement

Physical parameters of existing building walls are relatively stable, making it difficult to meet the thermal requirements under different seasons. In this study, phase change materials (PCMs) with different thermal conductivities and melting points were adopted to form a breathable heterogeneous phase change material (B&H-PCM) wall to achieve the year-round heating and cooling load reduction. The effects of operation parameters on B&H-PCM and ventilated block (VB) wall were experimentally analyzed. As the hot air inlet temperature rose from 30 to 80 °C in winter, the heat storage capacity and liquefaction ratio continuously increased. The PCM heat storage rate was maximized at 50 °C with 26.7 %, and the liquefaction ratio of internal PCM was 100 % at 60 °C. As the air inlet velocity went up in winter/summer, the heat storage/dissipation capacity increased and the heat storage/dissipation rate changed oppositely. The maximum heat storage rate was 36 % at 0.5 m/s in winter, and the maximum heat dissipation rate was 58.7 % at 3 m/s in summer. The external/internal heat capacity and thermal resistance of B&H-PCM wall were 5.9/7.2 and 1.1/0.8 times of VB wall respectively, indicating that B&H-PCM wall had a better heat storage and resistance capacity both in winter and summer.

Revolutionizing solar water distillation: maximizing efficiency with pyramid solar stills enhanced by fins, evacuated tubes, nanomaterial, and phase change materials—a comprehensive review

Abstract The availability of water and energy is crucial for human survival, yet rising industrialization and population growth have escalated demand, particularly in developing economies. Despite efforts to address water scarcity, contamination persists, leading to widespread diseases. Conventional purification methods like reverse osmosis are effective but expensive and energy-intensive while boiling exacerbates air pollution. In this context, solar still systems present a promising solution, harnessing abundant sunlight to distill seawater into drinkable water. By integrating phase change material (PCM) and sensible heat storage, these systems can enhance efficiency and reduce energy consumption. This article explores the optimization of solar still systems through the selection of suitable PCM and sensible heat storage materials. The primary objectives are to improve distillation efficiency and heat recovery, making the process more eco-friendly and cost-effective. By addressing water scarcity and energy consumption simultaneously, these optimized systems offer a sustainable approach to water production, particularly in regions with ample sunlight. Through a comprehensive review, this research aims to advance the understanding of solar still technology and facilitate its widespread adoption, ultimately contributing to global efforts toward water security and environmental sustainability.

Analysis of thermal characteristics and thermal storage performance of energy-saving phase change thermal storage materials in buildings

In order to explore the thermal characteristics and thermal storage performance analysis of energy-saving phase change heat storage materials in buildings, taking the common exterior wall insulation composite wall structure in southwestern China as an example, the influence of insulation board structure thickness design on the total cost of residential air conditioning energy consumption and insulation board cost is studied, thus clarifying the concept and calculation origin of economic insulation thickness. The experimental results show that by drawing mathematical functions of energy consumption cost, total cost, and insulation material cost in the same 2-D coordinate, it is intuitively demonstrated that the minimization of total cost can be ensured when the insulation thickness is in an economic state, and the specific economic thickness can be accurately calculated through example data. Therefore, specific measures for improving external wall insulation from refined insulation structure design are proposed. It has been proven that the design of the exterior wall insulation layer structure is an important way to improve the overall energy-saving benefits of building exterior wall insulation.

Visual Simulation of Composite Material Performance Inspection and Interior Decoration Based on Sensor Image Recognition

Abstract Wood-plastic composites, as green eco-materials, are widely used in the field of home and building materials, but with a single function. Phase-change heat storage materials can store or release heat through a physical phase transition to achieve energy savings and emission reduction. In this paper, plant fibers are used as the matrix, which is introduced into wood-plastic composites to construct a function/structure-integrated shaped phase change heat storage wood-plastic composites and endow the wood-plastic composites with the function of storing and releasing heat. The performance of wood-plastic composites is examined using image recognition and X-ray imaging. Simulating and analyzing the thermoregulatory and energy-saving functions of phase change wood-plastic composites in the building heating environment was done by establishing a heat transfer model. Finally, the material was visualized and applied to the interior decoration. The results show that the apparent density of the wood-plastic composite material is 1.15 g/cm3, the tensile property is 42.8 MPa, the flexural modulus is 2455 MPa, and its comprehensive physical and mechanical properties are better than those of the solid wood core when the amount of plant fiber added is 40 phr. At the same time, the thermal conductivity of this material is improved by 7.74% compared with the traditional solid wood core, which shows good energy saving and temperature regulation effects and possesses the potential of energy saving when applied in interior decoration.

Thermal performance analysis and thermal environment creates effect of a novel solar hot-air phase change bed

Comprehensive heating provides a comfortable indoor but consumes significant energy. Temporal-spatial partitioned heating can meet differentiated thermal demands while reducing energy consumption. A novel solar hot-air phase change bed heating system has been proposed for achieving temporal-spatial partitioned heating. Theoretical analysis models have been established to study the heat transfer process of the hot-air phase change heating bed, and numerical simulations have been conducted to analyze its thermal performance and creation of a comfortable environment. The results demonstrate that at the end of the heat storage, the bed board temperature increased by 1.5 °C for every 5 °C increase in the wind temperature. The maximum temperature difference of the bed board reached 6.1 °C under three different wind speed schemes. During heat release, the bed board heat flux was affected by the phase change material heat storage difference, and the maximum temperature difference of the bed board reached 4.3 °C ∼ 6.7 °C under different schemes. After the first cycle, both indoor and bed board temperature were higher than the initial values. During the daytime, there was excessive heat indoors, and the maximum environmental temperature exceeded the comfortable range by 8.7 °C. At night, the bed was covered with a high-temperature layer, and the bed surface temperature was uniformly distributed, remaining in the thermal comfort zone for 3.8 h to 5.1 h. The research results provide a basis and guidance for utilizing solar hot-air phase change beds to improve differentiated thermal demands.

Optimization research on battery thermal management system based on PCM and mini-channel cooling plates

A phase change materials (PCM) coupled mini-channel cooling plates model was established for the optimization of the battery thermal management system (BTMS). Specific cooling strategies with different discharge rates of the battery were discussed. For a discharge rate of under 2C, using PCM can meet the heat dissipation needs. Particularly, for a discharge rate below 1.2C, external cooling was not necessary. For a discharge rate above 2C, active cooling should be added to compensate for the lack of heat storage of PCM. In the research of optimization structure, it was found that the scheme of four cooling plates and each cooling plate with two mini-channels was the most ideal in this research, which not only reduced the battery temperature efficiently but also maintained a good temperature uniformity of the battery. For the optimization parameters, the effect of the ethylene glycol solution temperature, ethylene glycol solution volume fraction and the start-up time of active cooling on the maximum temperature of the battery and the melting fraction of PCM were discussed. After the multi-factor parameters optimization by Response Surface Methodology, three optimization schemes were put forward, which could reduce the driving power consumption by 35% – 40%. The research could provide valuable information support and optimization suggestions for the design of BTMS.