Shape-stabilized Phase Change Materials Research Articles

Synergistic phase change and heat conduction of low melting-point alloy microparticle additives in expanded graphite shape-stabilized organic phase change materials

Organic phase change materials (PCMs) have great potential for efficient thermal energy storage and passive thermal management applications due to their non-corrosiveness, high heat storage capacity and stable operating temperature. However, low thermal conductivity and easy leakage seriously restrict the actual application. Meanwhile, heat transfer enhancers typically have a serious negative effect on the heat storage capacity of the PCMs. In this paper, a novel strategy for preparing high performance shape-stable composite phase change materials (CPCMs) is reported, utilizing paraffin wax (PW) as the energy storage material and expanded graphite (EG) as heat transfer enhancers and supporting material, especially in which low melting-point alloy (LMA) micro particles having same phase change temperature as PW are employed with two purposes: one is to provide extra latent heat, and another is to construct a hybrid three-dimensional thermal conduction network in microscale to achieve synergistic thermal conduction with EG. The resulting CPCMs exhibit excellent characteristics in energy storage capacity, thermal conductivity, and thermal cycling stability. The thermal conductivity of ternary CPCM can reach 5.842 W m−1 K−1 when the LMA and EG loading are 4.55 wt% and 9 wt%, which is about 16.4 times higher than that of pure PW, with no obvious volumetric latent heat reduction. This work provides a novel and promising approach for the preparation of CPCMs with high and fast storage properties.

Enhanced Gypsum Boards with Activated Carbon Composites and Phase Change Materials for Advanced Thermal Energy Storage and Electromagnetic Interference Shielding Properties

This work presents the development of novel gypsum board composites for advanced thermal energy storage (TES) and electromagnetic interference (EMI) shielding applications. Activated carbon (AC) derived from spent coffee with a high surface area (SBET = 1372 m2/g) was used as a shape stabilizer, while the commercial paraffin, RT18HC, was used as organic encapsulant phase change material (PCM). The AC showed a remarkable encapsulation efficiency as a shape stabilizer for PCM, with ~120.9 wt% (RT18HC), while the melting enthalpy (ΔHm) of the shape-stabilized PCM was 117.3 J/g. The performance of this PCM/carbon nanocomposite as a thermal energy storage material was examined by incorporating it into building components, such as gypsum wallboards. The microstructure of these advanced panels, their density, and their dispersion of additives were examined using X-ray microtomography. Their thermal-regulated performance was measured through a self-designed room model with a similar homemade environmental chamber that was able to create a uniform temperature environment, surrounding the test room during heating and cooling. The measurements showed that the advanced panels reduce temperature fluctuations and the indoor temperature of the room model, in comparison with normal gypsum panels, by a range of 2–5%. The investigated gypsum board composite samples showed efficient electromagnetic shielding performance in a frequency range of 3.5–7.0 GHz, reaching an EMI value of ~12.5 dB, which is adequate and required for commercial applications, when filled with PCMs.

Carbonated balsa-based shape-stable phase change materials with photothermal conversion and application in greenhouse

Greenhouse enables to promote plant yield through creating optimal environment. Efficient solar energy conversion and storage is a promising strategy to address energy shortage issue of greenhouse in winter. This paper prepares form-stable composite phase change materials (PCMs) to store solar energy efficiently. Lightweight and porous balsa wood subjected to high-temperature carbonization is designed to simultaneously solve the liquid leakage, enhance the thermal conductivity, and improve the photothermal conversion and thermal energy storage of PCM. OP44E and SEBS are utilized as PCM and thickener, followed by vacuum impregnation into the carbonized balsa wood (CW). Results indicate that carbon content of CW increases with the augment of carbonization temperature. Shaping effects of CW and SEBS endow composite PCMs to have highest adsorption rate of 92.7 wt% with enthalpy over 190 J/g. Composite PCMs reveal reliable thermal properties and thermal stability below 100 °C. Composite PCMs have photothermal conversion larger than 88 % under a xenon lamp radiation. Temperature of PCMs on the shallow layer is higher owing to its photothermal conversion capacity. Greenhouse test indicates that CW/OP44E/SEBS greenhouse gains higher PCM temperature of 71.5 °C at 70 min, compared to 40.3 °C in empty and OP44E/SEBS cases. CW/OP44E/SEBS greenhouse maintaining indoor temperature over 20 °C lasts 15.3 min longer than empty and OP44E/SEBS greenhouses. In addition, form-stable composite PCMs featured with excellent thermal stability and photothermal conversion are capable of maintaining stable indoor temperature of greenhouse, indicating potential in the field of agricultural building temperature regulation.

Characterization of novel lamellar porous Ti3SiC2 as shape-stabilized high-temperature phase change materials composites for durable enhancement thermal storage properties

In pursuit of leveraging porous media for high-temperature phase change materials (PCMs) to enhance the overall thermal conductivity and encapsulation performance of PCMs, this study delves into the corrosion behavior of Ti3SiC2 with a lamellar porous structure in different corrosive environments at both high and low temperatures. By manipulating the solid content to modify the porous structure, the investigation probes the corrosion phenomena and anti-corrosion mechanisms across various porous configurations. The results reveal that F ions exert the most extensive structural degradation on Ti3SiC2. Based on these insights, a successful fabrication of a molten salt phase change composite material, Ti3SiC2/KCl-NaCl, boasting a lamellar structure was achieved. With an increase in solid content, the thermal conductivity escalates from 6.13 to 9.27 W/(m∙K), tripling the heat conductivity of pure KCl-NaCl. However, this also leads to a reduction in latent heat from 126.7 J/g to 46.2 J/g. Consequently, the phase change energy storage performance of PCM prepared by sample 2 emerges as exceptionally commendable. Following 200 thermal cycles on the composite PCM, no discernible structural damage was observed, albeit a slight performance decline. Hence, the lamellar Ti3SiC2/KCl-NaCl structure not only boasts favorable phase change energy storage capabilities but also demonstrates an extended service life.

Processable and shape-stable phase change materials with enhanced thermal conductivity of UV-cured NPGDMA aided PEG2000 and BN

Polyethylene glycol (PEG) has several drawbacks, including poor shape stability, low thermal conductivity, and challenges with complex molding. In this work, a rapid and simple approach for producing phase change materials (PCMs) with high thermal conductivity and good shape stability is reported. The neopentyl glycol dimethacrylate (NPGDMA) monomer is polymerized utilizing UV-cured technology, which can offer a cross-linked network to stop PEG2000 leakage and enhance the heat conductivity of the composite by adding BN. The best PEG2000-to-NPGDMA ratio in the PEG2000/NPGDMA/BN PCM is found to be 9:1, taking into account the shape stability and energy storage of the PCMs. The ideal amount of BN to add is 5 wt%, which improves the thermal conductivity by about 52.1 %. According to the DSC test, PEG2000/NPGDMA/BN has a significant capacity for storing heat with a melting enthalpy of up to 139.3 J/g. The PEG2000/NPGDMA/BN composite passed with good thermal cycling performance and no change in group composition after 101 thermal cycles. The prepared PCMs can be formed into complex shapes for use in particular applications.

Bio-based sunflower carbon/polyethylene glycol shape-stabilized phase change materials for thermal energy storage.

The exploitation of shape-stabilized phase change materials with high thermal conductivity and energy storage capacity is an effective strategy for improving energy efficiency. In this work, sunflower stem carbon/polyethylene glycol (SS-PEG) and sunflower receptacle carbon/polyethylene glycol (SR-PEG) shape-stabilized phase change materials, utilizing sunflower stem and receptacle biomass carbon with high specific surface area and pore volume obtained by carbonization as frameworks and polyethylene glycol as an energy storage material, were prepared by the vacuum impregnation method. The ability to load polyethylene glycol into the pore structure of carbon materials in different sunflower parts was mainly investigated, and the micro-morphology, compositional structure and thermal properties were characterized and analyzed using SEM, IR spectroscopy, XRD, DSC and TG techniques. The results showed that the carbonized sunflower stems maintained the sieve pore structure, and the carbonized sunflower receptacle was a macroporous structure containing a large number of three-dimensional interconnections. At the same time, the interaction between polyethylene glycol and each carbon material occurred through physisorption. The melting enthalpies of SS-PEG and SR-PEG shape-stabilized phase change materials were 153.4 J g-1 and 171.5 J g-1, respectively, and the loading rates reached 81.9% and 91.5%, with initial thermal decomposition temperatures (T 5%) of 344 °C and 368 °C.

Preparation of Waste Incorporated Bio-Smart Shape-Stable Phase Change Material (FSSPCM) with Responsive Fluorescent Properties

Preparation of Waste Incorporated Bio-Smart Shape-Stable Phase Change Material (FSSPCM) with Responsive Fluorescent Properties

Shape-stabilized phase change materials based on polyvinyl alcohol/graphene hybrid aerogels for efficient solar-thermal energy conversion

Shape-stabilized phase change materials based on polyvinyl alcohol/graphene hybrid aerogels for efficient solar-thermal energy conversion

Cellulose nanocrystal stabilized copper nanoparticles for grafting phase change materials with high thermal conductivity

Phase change materials (PCMs) have recently garnered significant attention for thermal energy storage applications. However, widely used PCMs, such as polyethylene glycol (PEG), suffer from low heat conductivity, poor thermal stability, and a tendency to leak, limiting their practical use. Therefore, the objective of this study is to develop a highly thermally conductive composite PCM using PEG and a thermally conductive nanomaterial, specifically cellulose nanocrystals supported by copper nanoparticles (CNC@Cu-NPs). The CNC@Cu-NPs nanocomposite material was used as a matrix to support polyethylene glycol (PEG), resulting in a shape-stable phase change material termed PEG/CNC@Cu-NPs. The obtained PEG/CNC@Cu-NPs were characterized using various analytical techniques. Fourier transform infrared spectroscopy (FTIR) analysis revealed the chemical linkages between PEG and cellulose nanocrystals through a radical polymerization reaction. Polarizing optical microscopy (POM) images of PEG/CNC@Cu-NPs exhibited spherocrystal morphology with smaller sizes compared to pure PEG, suggesting that CNC inhibited PEG side-chain mobility. According to differential scanning calorimetry, the suggested PEG/CNC@Cu-NPs demonstrated a temperature transition between 0.51 °C to 24.5 °C with enthalpies of fusion and crystallization measured at 92.19 and 98.54 J/g, respectively, while also exhibiting excellent cycling stability after 60 heating/cooling cycles. The addition of a modest amount of copper nanoparticles resulted in a remarkable improvement (>50 %) in the thermal conductivity of the PCM. Thermal imaging using an infrared camera showed that PEG/CNC@Cu-NPs exhibited a delay of 10 min in heating compared to pure CNC, confirming the good heat retention capacity of the developed composite material. Based on the aforementioned findings, the proposed PEG/CNC@Cu-NPs PCM offers promising application possibilities in the field of thermal energy storage.

Converting bio-waste rice into ultralight hierarchical porous carbon to pack polyethylene glycol for multifunctional applications: Experiment and molecular dynamics simulations

A structural-functional integrated shape-stabilized composite phase change material (PCM) was synthesized by converting biowaste rice into ultralight (0.08 g/cm3) hierarchical porous carbon (CNR) to pack polyethylene glycol (PEG) PCM. The thermal property and corresponding mechanism were analyzed. The results show that the composite PCM exhibits excellent thermal storage efficiency (93.3 %), considerable solar photothermal conversion efficiency and superior thermal stability. The interfacial thermal resistance (ITR) of PEG/CNR is 73 % lower than graphene foam-based composite PCM thus a fast transient temperature response. Particularly, the package of PEG endowed composite PCM with elastic characteristic thereby an enhanced compressive strength. Furthermore, covering PEG/CNR results in a delay of approximately 1.3 times in reaching the peak temperature on the surface of electronic components, and a delay of 5 times in cooling time. This study presents solid guidelines for societal development that is sustainable and makes some recommendations for construction of composite PCMs combining multifunctional applications.

Evaluation of shape-stabilized phase-change materials using calcium carbonate-based starfish microporous materials for thermal energy storage

This study investigates the synergistic potential of shape-stabilized phase-change materials (PCMs) integrated with calcium carbonate-based starfish microporous materials for efficient thermal energy storage. By addressing challenges related to traditional PCMs, such as leakage and stability, this research aims to enhance thermal energy storage capabilities. Starfish and bio-based PCMs prepared from starfish were subjected to porosity, thermophysical, and chemical analyses. The porosity analysis revealed that the surface and skeleton of the starfish had sufficient porosities to contain liquid PCMs inside, and the bio-based PCM formed closed cells in the starfish, effectively blocking leakage to the outside. The maximum latent heat, which indicates the thermal energy storage capacity, was 57.66 J/g. This demonstrated thermal stability below 150 °C, making it suitable as a building material. The chemical analysis revealed that bio-based PCM was composed of carbon, oxygen, and calcium commonly found in sea creatures, and it was confirmed that there was no chemical change during phase stabilization, confirming that it was chemically stable. Therefore, the manufactured bio-based PCM has potential as an eco-friendly heat-storage material.

Effect of CNTs length on thermophysical properties of paraffin/CNTs/graphene aerogel nanocomposite as a shape stabilized phase change material

In this work, paraffin/carbon nanotubes/graphene aerogel (Pa/CNTs/GA) nanocomposite with different CNTs lengths were synthesized. CNTs' length was changed by refluxing them in a mixture of acids for different times, by which the initial micrometer length of CNTs was reduced to 1200 and 205 nm after 0.5 and 1 h refluxing. To complete dispersing CNTs in paraffin, they were functionalized for the second time using dodecylamine. By inserting paraffin composites into the aerogel using vacuum impregnation, the thermal conductivity of the aerogel increases greatly. Melting and freezing latent heat of both samples of graphene aerogel composite containing 0.5 and 1 h refluxed CNTs was reduced compared to that of the pure paraffin and Pa/CNTs composite. The specific heat of the Pa/CNTs/GA composite containing 1 h refluxed CNTs was reduced compared to that of the Pa/CNTs (1 h refluxed) composite, but it was increased for the samples containing 0.5 h refluxed CNTs. Also, Pa/ZnO, Pa/TiO2, and Pa/Al2O3 composites were prepared and their thermophysical properties were compared with those of Pa/CNTs composites.

Experimental and numerical study of adaptive ventilation and sunlight regulation building envelope combining variable transparency shape-stabilized phase change material

The development of adaptive building envelopes with advanced PCM to reduce building energy consumption is a promising topic. This study proposed an adaptive ventilation and sunlight regulation wall (AVSRW) by combining the variable transparency shape-stabilized PCM (VTSS-PCM), reflective film, and ventilation cavity. The combination of VTSS-PCM and reflective film could passively regulate the solar absorptivity (SA) of AVSRW. The ventilation cavity with airflow control enhanced the heat storage and release efficiency of VTSS-PCM. A dynamic photo-thermal coupling model of the AVSRW was presented and validated by a full-scale experiment in summer and winter conditions. Then, based on the weather data of the typical meteorological year of Changsha, China, the performances of AVSRW on days, months, and a year were evaluated. The impact of three influential factors and their combined effects on the performance of AVSRW were analyzed. Ultimately, a global optimization was conducted to improve the performance of AVSRW, and compared with the massive wall. The results showed that the AVSRW passively decreased its SA on summer days and increased its SA on winter days. The total annual undesired heat exchange (TAHE) of AVSRW first decreased and then increased with the increase of melting temperature (Tm) and thickness (L) of VTSS-PCM. The reflective film had an opposite effect on the annual heat gain (AHG) and annual heat loss (AHL) of AVSRW, resulting in the TAHE remaining unchanged with the increase of reflectivity (R) of the reflective film. The greater the L, the smaller effect of the Tm and R on the AHG and AHL, and the greater the R, the greater effect of the Tm and L on the AHG and AHL. After optimization, the values of the Tm, L, and R corresponding to the optimal solution were 24.60 °C, 0.17 m, and 0.63, respectively. Compared with the reference wall, the AVSRW with the best performance had lower AHG and AHL, and the annual energy-saving rate of the AVSRW reached 43.49%. This study guides the application and parameter optimization of AVSRW in hot summer and cold winter regions.

Innovative flexible thermal storage textile using nanocomposite shape-stabilized phase change materials

A novel flexible thermal storage system based on organic phase change materials (PCMs) deposited on a non-woven polyester (PET) substrate is described in this article. Thermally regulating effects were created via encapsulation of polyethylene glycol (PEG) in carbon nanofibers (CNFs) to manufacture a shape-stable phase change material (SSPCM). Improvement in the thermal conductivity (TC) of the system was obtained by incorporating reduced graphite oxide nanoparticles (rGONP) into the CNFs. A new method was applied to load and secure the manufactured SSPCMs on the fibrous substrate so that an acceptable level of flexibility was preserved (change in bending length less than 30%). The sample performance was evaluated by measuring its thermal properties. The physical properties, wash fastness, abrasion resistance, morphology, and PCM leakage of the samples were also assessed. The results point to a good thermal storage ability of the samples with characteristic phase change temperature ranges of 30.1–31.4 °C and 19.2–24.3 °C for melting and freezing, respectively, and a latent heat of 8.9–22.9 J g−1 for meting and 11.2–21.4 J g−1 for freezing. The use of the CNF-rGONP for PEG enhanced the TC of the system by 454%, thus providing a rapid thermal response, and efficiently prevented the leakage of PEG. Finally, the loading and fixation method on the non-woven substrate allowed an acceptable level of durability with less than 4% of weight loss during washing and abrasion tests. This system provides a promising solution for rapid response, flexible thermal storage wearables.

Gold tailings-solar salt shape-stabilized phase change materials for medium-high temperature thermal energy storage

Gold tailings (GT) are a form of industrial solid waste generated by gold production that occupy large areas of land and cause a significant environmental burden. This study accordingly prepared a novel composite phase change material (CPCM) for medium-high temperature thermal energy storage using a hybrid sintering method to combine GT as the base material with solar salt (SS) as the phase change material. The resulting gold tailings composite phase change materials (GT-CPCM) was able to retain up to 45 wt% of SS without leakage. The results of an X-ray diffraction analysis suggested excellent chemical compatibility between the GT and SS, and scanning electron microscopy demonstrated an even distribution of SS within the GT structure. A mechanical characterization of GT-CPCM specimens revealed a maximum compressive strength of 36.66 MPa. Furthermore, the maximum latent heat of the GT-CPCM was 45.01 J/g, its thermal conductivity was 0.435 W/(m·K), and its energy storage density was 563.01 J/g within 25–400 °C. Critically, the GT-CPCM specimens had good cycling reliability after 100 thermal cycles. Thus, the mechanical and thermal properties of this novel CPCM make it ideal for waste heat recovery with the benefit of utilizing GT as a resource.

Controllable large-scale processing of temperature regulating sheath-core fibers with high-enthalpy for thermal management

Temperature regulating fibers (TRFs) with high enthalpy and high form stability are the key factors for thermal management. However, the enthalpies of most TRFs are not high, and the preparation methods are still at the laboratory scale. It remains a great challenge to use industrial spinning equipment to achieve continuous processing of TRFs with excellent thermal and mechanical properties. Here, polyamide 6 (PA6) based TRFs with a sheath-core structure were prepared by bicomponent melt-spinning. The sheath-core TRF (TRFsc) are composed of PA6 as sheath and functional PA6 as core, which are filled with the shape stable phase change materials (ssPCM), dendritic silica@polyethylene glycol (SiO2@PEG). With the aid of the sheath structure, the filling content of SiO2@PEG can reach 30 ​%, so that the enthalpy of the TRFs can be as high as 21.3 ​J/g. The ultra-high enthalpy guarantees the temperature regulation ability during the alternating process of cooling and heating. In hot environment, the temperature regulation time is 6.59 ​min, and the temperature difference is 12.93 ​°C. In addition, the mechanical strength of the prepared TRFsc reaches 2.26 cN/dtex, which can fully meet its application in the field of thermal management textiles and devices to manage the temperature regulation of the human body or precision equipment, etc.

Investigation on low-carbon shape-stable phase change composite by steel slag and carbide slag for solar thermal energy storage

Resources utilization of a variety of industrial solid wastes including steel slag (SS) and carbide slag (CS) is an effective measure that reduces environmental destruction and greenhouse gas emissions. In this work, seven shape-stable phase change materials (SSPCMs) with different mass fractions were prepared by cold compression-hot sintering (CCHS) method utilizing SS and CS as the skeleton material (SM) and NaNO3 as the phase change material (PCM). Research on critical properties of SSPCMs including thermal energy storage properties, microscopic morphology, mechanical properties, chemical compatibility, and economic properties was undertaken. Results indicated that various properties were optimized when the mass ratio of SS, CS, and NaNO3 was 2.5:2.5:5 (SC4). The mechanical strength of sample SC4 was 131.2 MPa, and the optimum thermal energy storage (TES) density in the temperature range of 100 °C–400 °C was 371.1 J/g. The maximum thermal conductivity of sample SC4 was 1.263 W/(m·K) after 1307 heating and cooling cycles. The sample SC4 exhibited favorable chemical compatibility and the elements were uniformly distributed in the sample SC4.

Adaptive building envelope combining variable transparency shape-stabilized PCM and reflective film: Parameter and energy performance optimization in different climate conditions

Developing an adaptive building envelope (ABE) to cope with drastic changes in the ambient environment contributes to achieving the goal of net-zero emissions by 2050 in the building industry. In this study, two types of ABE, namely, adaptive ventilation and sunlight regulation wall (AVSRW) and adaptive sunlight regulation wall (ASRW), were designed by combining variable transparency shape-stabilized PCM (VTSS-PCM) and reflective film, and the AVSRW had an air cavity to control the heat storage and release of VTSS-PCM. The numerical models of the two ABEs and the massive wall (MW) were developed and validated by a full-scale experimental test. Based on these validated numerical models and weather datasets in four climate zones of China, the energy performances of AVSRW were simulated under the influence of melting temperature (Tm) of VTSS-PCM, thickness (L) of VTSS-PCM, and reflectivity (R) of reflective film. Then, a bi-objective global optimization was conducted to find the optimal performance and design parameters of AVSRW. Finally, the AVSRW and the ASRW with the optimal design parameters were compared with and the MW. The parameters analysis revealed that the combined action of Tm, L, and R on AVSRW determined the trade-off among the heat conducted to the interior, the solar energy stored by VTSS-PCM, and the solar energy reflected by the reflective film. The optimization results showed that, in the climate conditions of Beijing, Changsha, Guangzhou, and Harbin, the optimal values of Tm were 24.02 ℃, 24.37 ℃, 25.86 ℃, and 23.43 ℃, respectively; the optimal values of L were 0.16 m, 0.16 m, 0.09 m, and 0.16 m, respectively; the optimal values of R were 0.23, 0.29, 0.79, and 0.33, respectively. Under the optimal values of Tm, L, and R, compared with MW, the annual ESRs of AVSRW and ASRW were 84.26 % and 38.71 % in Beijing, 81.98 % and 39.45 % in Shanghai, 70.28 % and 55.53 % in Guangzhou, 76.20 % and 29.54 % in Harbin. This study provides the basis for the design and optimization of AVSRW and ASRW in different climate regions.

Research on dolomite-based shape-stabilized phase change materials for thermal energy storage: Feasibility study of raw and calcined dolomite as skeleton support materials

Mid and high-temperature inorganic salts have limited applications due to their corrosiveness and low thermal conductivity. Shape-stabilized phase change materials (SSPCMs) can ease these issues. This study explored using dolomite, an affordable and abundant mineral with good thermal properties, in SSPCMs. We developed SSPCMs using raw and calcined dolomite at 700 °C, 750 °C, and 800 °C (700Do, 750Do and 800Do) as skeletal support materials (SSMs) and NaNO3-KNO3 as the phase change materials (PCMs). Calcined dolomites had a porous structure compared to raw dolomite (RawDo). 700Do, 750Do and 800Do require a minimum of 50 wt%, 40 wt% and 30 wt% to stabilize the shape of the sintered material by 100 cycles. RawDo was unsuitable for SSM during cycling. XRD confirmed chemical compatibility between components, and SEM showed an even distribution of SSMs within the PCMs. The thermal conductivity of SSPCMs ranged from 1.09 to 1.27 W/(m·K), compared to 0.52 W/(m·K) for NaNO3-KNO3. The NaNO3-KNO3 has a latent heat of about 110.60 J/g and a supercooling degree of 5.84 °C. The latent heat of SSPCMs depends on the proportion of SSMs, slightly lower than the theoretical value by 0.01 %–2.37 %, and the supercooling degree of SSPCMs varies between 4.75 °C and 6.25 °C. The SSPCMs were chemically stable with little latent heat change after 100 cycles, showing excellent cycling stability. The thermal decomposition temperature of SSPCMs containing 700Do was about 580 °C, while SSPCMs containing 750Do and 800Do exhibited a minor decomposition onset at around 380 °C, attributed to Ca(OH)2 decomposition. The best-performing SSPCM contained 30 wt% 800Do, offering a thermal conductivity of 1.27 W/(m·K) and thermal energy storage density of 359 kJ/kg in the 100–320 °C range. In general, calcined dolomite-based SSPCMs offer excellent thermal energy storage performance at a low cost compared to many SSPCMs.

Preparation and properties of shape-stable phase change material with enhanced thermal conductivity based on SiC porous ceramic carrier made of iron tailings

SiC porous ceramic carriers with adjustable porosity of 79.9%–90.7% were prepared by foam gel-casting forming and carbothermal reduction reaction sintering, using industrial waste fine-grained iron tailings and graphite powder as raw materials. Then paraffin/SiC shape-stable phase change materials were prepared by spontaneous infiltration employing paraffin as phase change material. Thermal conductivity of the SiC carriers (0.17–0.31 W/m·K) is 2.7–3.7 times higher than that of iron tailings porous ceramics with the same porosity. A thermal conductivity model of the SiC carrier is established and verified by experimental data. Phase composition, microstructure, molecular structure, mechanical properties and thermal properties of the shape-stable phase change materials were characterized by XRD, SEM, FT-IR, WDW, Hot Disk and DSC, respectively. There is only a physical combination between paraffin and SiC carriers. The compressive strength of the shape-stable phase change materials (2.0–2.3 MPa), weight loss and latent heat loss are less than 5% and 4.7% after 100 thermal cycles, respectively, which can meet the application requirements as a functional material. Thermal conductivity of the shape-stable phase change materials (0.7–0.73 W/m·K) is significantly improved, a latent heat of 138.5 J/g, and the efficiency of energy storage and release is 2.3–3.3 times as good as than that of paraffin, suggesting that this material is capable of recycling and reusing waste heat as a highly efficient thermal energy storage system.