Mixture Of Phase Change Materials Research Articles

Impregnation of Activated Carbon with Organic Phase-Change Material.

In this study, we developed a thermal storage medium comprising porous activated carbon filled with organic phase-change materials (PCMs) that utilizes the latent heat of phase-change to absorb heat during heating and release heat during cooling. For the activated carbon, we used both charcoal-based powdered activated carbon (250-350 mesh) and granular activated carbon. The organic phase-change materials used in the experiments were dodecane, tridecane, tetradecane, and pentadecane. Material properties such as thermal conductivity, latent heat, and melting temperature range were evaluated experimentally and theoretically, with the results observed to be consistent. The cyclic thermal performance of the proposed medium was also evaluated. Notably, filling the activated carbon with a mixture of organic PCMs resulted in the highest temperature-moderating effect. The procedure and results presented in this study are expected to aid in further improvement in the performance of thermal storage media containing PCM where stable temperatures are required, including building heating and cooling.

A review on thermal energy storage with eutectic phase change materials: Fundamentals and applications

The storage and use of thermal energy have gained increasing attention from various countries. Phase change materials (PCMs) are commonly used in thermal energy storage (TES) applications due to their high latent heat. More than a hundred single-component PCMs have been reported, each with a specific phase change temperature. In addition to single-component PCMs, eutectic phase change materials (EPCMs) are also used in TES. EPCMs are homogeneous mixtures of binary, ternary, or multiple-component PCMs that melt at a unique temperature lower than the melting point of any of the constituents. Compared to single-component PCMs, EPCMs demonstrate superior performance in TES applications, with a broader phase change temperature range and improved phase stability. This review provides an overview of over 250 organic/inorganic EPCMs from eutectic theory, material classification, thermophysical properties, preparation and characterization methods, techniques for thermal performance improvement, and applications. The review also concludes with a discussion of future prospects and findings that EPCMs can enhance heat storage density and thermal stability when compared to single-component PCMs. This information serves as a reference for the development of heat storage materials with improved thermal physical properties in the future. Overall, this review provides a comprehensive summary of EPCMs from their fundamentals to applications.

Influence of self-cleaning coating on performance of photovoltaic solar system utilizing mixture of phase change material and Graphene nanoparticle

Improvement of electrical efficiency of photovoltaic systems with utilizing self-cleaning approach has been scrutinized in present work. The dust accumulation has a negative efficacy on the performance of the unit and the optical feature of glass has been improved with coating SiO2 nanoparticles. The finned tank of paraffin (RT25) has been utilized for cooling of silicon cell and cooling tube has been utilized in the middle section. The dispersion of Graphene nanoparticles within paraffin and water makes the heat absorption increase. The single phase formulations for both cooling zones have been incorporated and gravity force has been neglected in the model. Numerical approach has been utilized for unsteady simulation and validation section proved the good agreement of current code. The uniformity of cell temperature enhances about 29.53% with mounting fins. Loading nanoparticles causes the liquid fraction to increase about 4.58%. With installing fins, the electrical performance enhances and such increment enhances about 10.22% for coated glass when t = 3600s. Utilizing fins can increase the amount of CO2 reduction about 10.22%. Also, reduction of emission improves about 29% by utilizing glass with coating.

Fuel, cost, energy efficiency and CO2 emission performance of PCM integrated wood fiber composite phase change material at different climates

Wood fiber is a great potential supportive material for creating a new composite the phase change materials (PCM) due to its beneficial qualities, including high sorption competency, low density, enviro -friendliness, economic effectiveness, and chemical inertness. The main objective of this paper is to study the effect of using the wood fiber/eutectic mixture of stearic and capric acid on the fuel, cost, and carbon emission-saving potentials for various PCM cases. Which experiences a phase transition within the thermally pleasant temperature range of buildings, used for the building's thermal energy storing purposes and consumption cost saving. The energy performance analysis was carried out for buildings incorporated with stearic and capric acid eutectic mixture of PCM with wood fiber-based insulation material (INS) in different climate regions. The results showed that the largest energy-saving capacity belongs to PCM5. The energy saving reaches 52.7% for PCM5 for a thickness of 0.1 m. The PCM1, PCM2, PCM3, PCM4 can provide energy saving rates of 23.5%, 34.3%, 44.7% and 50.5%, respectively. INS-PCM5 can provide about 1.74-, 1.5-, and 1.33 times larger cost savings than INS in 2nd, 3rd, and 4th regions for all fuels. The payback period varies between 0.37 and 5.81 years regarding the fuel and Region. Finally, the results indicate that the proposed composite provided a promising energy-saving potential in building applications by reducing.

Numerical analyses of energy screw pile filled with phase change materials

Embedding heat exchangers into a screw pile can form a cost-effective energy pile with a fast installation capability. However, better solutions to handle thermal waves and thermal interferences among energy piles are still required. This work aims to solve the issues by proposing a novel concept of an energy screw pile filled with mixtures of phase change materials (PCM) such as paraffin and “solid” grouting. Numerical simulations are conducted to investigate the utilisation of PCM energy screw piles on reducing fluid and ground temperatures, considering different constituents in PCM-solid mixtures, moisture conditions, phase change temperatures Tpc and operation schemes. Results demonstrate that a mixture with higher effective thermal conductivity λeff slows down the PCM phase transition and results in a lower fluid temperature feeding the ground source heat pump (GSHP). Dry mixtures with higher PCM content benefit the fluid temperature reduction, while a lower PCM content in a wet mixture is also satisfactory. Higher specific heat capacity allows pile back-filling to absorb more heat and reduce the thermal radius of influence, while over-enhancing its λeff might worsen thermal interference. The selection of the PCM phase change temperature Tpc should comply with the GSHP system operation scheme and the project aim.

Thermal design of solar thermoelectric generator with phase change material for timely and efficient power generation

Solar thermoelectric energy-generation technology is being developed to mitigate the limitations of solar cells. Thermal management is essential to creating highly efficient and stable solar thermoelectric generators (STEGs). Phase change materials (PCMs) can be used to improve the performance of STEGs. In this study, we numerically investigate the heat transfer, thermal energy storage, and thermoelectric energy conversion in an STEG with PCMs (STEG-PCM). Based on a parametric study, we present thermal design guidelines for the configurations of an STEG-PCM and the thermal properties of PCMs by considering both the thermoelectric generation performance and thermal stability of the STEG-PCM. We also show that the PCM-impregnated structure is the most crucial component of the STEG-PCM in the thermal design based on a sensitivity analysis. To find the optimal design of a PCM-impregnated structure, topology optimization is performed for the STEG-PCM focused on daytime thermoelectric generation performance. The topology-optimized PCM-impregnated structure shows a thermoelectric generation performance close to that of an STEG-PCM whose PCM-impregnated structure is assumed to be an ideal mixture of PCM and framework material. This study explains how PCMs affect thermal energy transport and conversion in an STEG and sheds light on a highly efficient and stable STEG system.

An intelligent icephobic coating based on encapsulated phase change materials (PCM)

The phase change materials (PCMs) have attracted great interest for applications as smart icephobic coatings because of their capability to restore and release energy. PCMs release a large amount of energy as latent heat upon freezing, which is a stimuli-response behavior for anti-icing applications. Such materials embedded within coatings can be applied to exposed infrastructures to protect them against icing. Here, we encapsulated a mixture of PCMs in a urea–formaldehyde (UF) shell by in situ polymerization and then incorporated the microcapsules into a polydimethylsiloxane (PDMS) coating. Microcapsules 5–15 µm in diameter having a shell thickness of about 200 nm were fabricated. Investigating the chemical composition of the fabricated microcapsules confirmed that PCM material was successfully encapsulated within the UF shell. Moreover, the differential scanning calorimetry (DSC) analysis showed that the PCM preserved its phase-change characteristics when encapsulated and embedded within the matrix. Increasing the abundance of microcapsules within the coating lowered the ice nucleation temperature, verified by DSC, and increased the freezing-delay time because of PCM latent heat release. We utilized a custom-made apparatus, called micro-push-off set-up that allowed us to measure ice adhesion at the exact moment that the water droplet was completely frozen. Therefore, it was observed that the presence of the PCM microcapsules reduced ice adhesion strength, through either possible mechanism of the formation of quasi-liquid layer (QLL) or thermal expansion differences. Furthermore, lower ice adhesion resulted in reduced ice accumulation on the PCM-containing coatings, verified by the static accumulation test (SAT).

Multimodal Fluorescence Switching Materials: One Dye to Have Them All

AbstractOff/on, on/off, and on1/on2 fluorescence switching systems find application in a variety of areas, for each of which a particular dye or dye‐switch tether must be specifically designed and synthesized. Herein it is demonstrated that such tight requirement can be avoided by using easily prepared mixtures of readily available emitters and phase change materials (PCMs). By proper selection of the PCM and, if needed, additives, thermo‐ and photothermoresponsive materials showing all classes of emission switching modes can be prepared from a single dye and without chemical modifications. This strategy can be generalized to distinct emitters and, thanks to the facile and versatile printability of dye–PCM mixtures, it can be used for the fabrication of fluorescent patterns showing complex (photo)thermal responses with direct applicability in sensing and anti‐counterfeiting.

Thermal performance improvement of energy storage materials for low operating temperature solar water heating systems

Recent studies have shown the attractive energy storage capabilities of phase change materials (PCMs); however, PCMs may not be fully effective due to their poor heat transfer characteristics. Moreover, the melting point of PCMs restricts direct integration into a solar collector for low operating solar water heating (SWH) applications. This study investigates the heat transfer enhancement of PCMs as well as aiming to lower their melting point onset to expedite the latent heat storage initiation. The selected types of PCMs are paraffin waxes with melting point temperatures of 28–72 °C. In Phase I, silicone oil is selected as a heat transfer medium to be used with the PCMs to establish natural convection enhancement, which led to maximum melting point depression of approximately 3 °C in the PCM72. In Phase II, the conductive heat transfer enhancement was studied by adding nanoparticles with varying mass concentrations. From this analysis, it was determined that PCM72 with 1% multi-walled carbon nanotubes (MWCNT) has shown an increase of approximately 3.81% in thermal conductivity. The obtained results from this study can lead to overall efficiency improvement of SWH systems by employing the PCM mixtures with low melting point, while keeping the high latent heat capacity, and high thermal conductivity.

Development of an effective algorithm for selection of PCM based filler material for thermocline thermal energy storage system

Thermocline Thermal energy storage is an imperial technology to improve the reliability of solar thermal energy systems. Inorganic Phase Change Materials (PCM) are more promised filler materials to increase the energetic and exergetic efficiency of the thermocline tank. Due to technological advancement, new materials are developed every year that support thermal energy storage. This article proposes the ITARA-TOPSIS-MODM methodology for the PCM selection process effectively. The final obtained results are experimentally validated, and the performance has been evaluated in the computation domain - Ansys, Fluent-21. The 62-commercially available inorganic salt and its mixture of PCM are collected and solved in the ITARA-TOPSIS method. The weightage of the attributes is found from the proposed ITARA method, and results are compared with conventional methods. In the pre-screened process, the attribute weights are obtained and substituted in the TOPSIS algorithm and sorted into ten materials in each category (i.e., L, M, and H). The properties of the sorted material are formed by two vital variables such as energy storage per unit volume and equivalent thermal diffusivity. The collected results are solved by the MODM tool. Finally, found L7, M7, and H17 (i.e. LiOH (6)-NaNO3(67)-NaOH (27), NaOH, Li2CO3(44)-Na2CO3(56), and NaF) to be more promised materials for the thermocline tank in solar thermal concentrating applications.

Functionally graded optimisation of adsorption systems with phase change materials

Adsorption phenomena are encountered in several engineering applications. One of its uses is in the storage and transport of gas in the form of adsorption tanks. The exothermic nature of the adsorption process decreases adsorption capacity presenting an impetus to understand the thermal characteristics of the gas storage process. Studies using mixtures of phase change materials and adsorbents in adsorption tanks demonstrate potential improvements in the adsorption capacity of the tanks. They also show that the distribution of phase change materials and adsorbent are important. Thus, this work presents two approaches for optimising the adsorbent domain. The first is to use a semi-analytic model to determine the best homogeneous material concentration for the adsorbent and phase change material for the vessel composition. The other is to use a 2D axisymmetric model to perform FGM optimisation to distribute material in the tank. Results for both models are presented and discussed for different conditions. The study shows that, for the cylindrical geometry, FGM optimisation is always, at least, marginally better than the homogeneous distribution from the semi-analytic model. However, FGM optimisation demands more computing time increases the complexity of implementation and results assembling. The semi-analytic approach is a possible alternative for optimising adsorption systems with phase change material mixed with adsorbents.

Effect of Paraffin and Silica Matrix Phase Change Materials on Properties of Portland Cement Mortars.

In the search for methods to incorporate Phase Change Materials (PCM) into Portland cement mortar mixtures, PCM based on paraffins adhered to a silica-based matrix appear as a suitable option. However, paraffin particles have been observed to escape from the silica matrix when water is added. There are only limited data on how the use of such PCM affects the behaviour of mortars. To evaluate the effect of this PCM addition, Portland mortar mixtures were elaborated with 5%, 10% and 15% of PCM content, and using CEM 42.5 I R and CEM I 52.5 R cement types. Physical properties such as density, open porosity, air content and water absorption were analysed for fresh and dry samples. The results obtained show that the PCM-added mixtures require greater water and cement amounts than the standard mortar mixtures to achieve similar compressive strengths. Compared to non-PCM mixtures the PCM-added mortars present a density lowering of 37% for fresh mixtures and near 45% for dry state forms. A maximum compressive strength of 15.9 MPa was reached for 15% PCM mixtures, while values beyond 40 MPa were achieved for 5% PCM mixtures. Thus, the proposed study contributes to broad the available knowledge of PCM cement mortar mixtures behaviour and their mix design.

Thermal analysis of Fe2O3 - myristic acid nanocomposite for latent heat storage

Phase change materials (PCM) are commonly utilized materials in latent heat energy storage (LHES) systems. In the present study, Fe2O3 was incorporated into myristic acid. The composites were prepared by melting and mixing method. The acids dispersed with Fe2O3 were prepared to enhance the thermal properties of the PCM mixtures and heat transfer at various nanoparticle loadings of 1 wt%, 2 wt%, 3 wt%, and 4 wt% were investigated. It was observed from the experimental results that the duration of melting and cooling rates for PCM composites increased in all nano compositions with respect to the pure myristic acid. Fourier transform infrared spectrum confirmed higher chemical stability of the nanoenhanced phase change material.

Studies on thermal properties of microencapsulated eutectic phase change material incorporated different mortar mixes

Microencapsulated eutectic mixture of phase change material (ME-PCM) was incorporated in different mortar ratios (that are used as an outer building envelope)to elucidate the ME-PCM effect on the thermo-physico properties. Thermo-physico parameters like compressive strength, bulk density, porosity, thermal conductivity, specific heat and water absorption were considered in the present work. Results obtained revealed that the physical parameters like compressive strength and bulk density decrease due to ME-PCM incorporation while water absorption increases with the increase in the ME-PCM content. Moreover, thermal conductivity and thermal diffusivity of mortar samples decrease gradually as compared to control samples, on the other hand, heat storage capacity increases with an increase in ME-PCM content. The findings of work will be of great use in the future and ME-PCM may be used in outer envelopes also as it epitomizes the delayed heat transfer from outer to inner envelope due to decreased thermal conductivity.

Optimization and Thermal Analysis of Fe2O3 Nanoparticles Embedded Myristic Acid-Lauric Acid Phase Change Material

Phase change materials (PCM) are commonly utilized materials in latent heat energy storage systems. In the present study, Fe2O3 was incorporated into the eutectic mixture of myristic acid and lauric acid. The composites were prepared by a melting and mixing method. Fourier transform infrared spectroscopy and dynamic light scattering results revealed the physicochemical properties of the eutectic mixture. Thermal analysis was performed on the optimized PCM mixtures with various Fe2O3 loadings of 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, and 5 wt.%. It is observed from the experimental results that the duration of melting and cooling rates for PCM composite with 4 wt.% Fe2O3 loadings was significantly improved, i.e., 85.72% and 78.31%, respectively, when compared to its pristine counterparts. These enhanced heating/cooling rates and thermal conductivity are attributed to the optimized impregnation of 4 wt.% Fe2O3 nanostructures into the eutectic mixture.

Experimental study of lithium-ion battery cooling using mixture of phase change materials

Phase change materials (PCM) are of attractive interest in electricity storage and power management applications. In this paper, PCMs are used for thermal management of an electric battery pack. Paraffin with a melting temperature of 58°C, OM35 with melting temperature of 35°C, two PCMs (paraffin and OM 35) were used for the study, as mixtures at two different ratios (50 : 50 and 60 : 40). Computations and experiments were allotted to estimate the heat transfer, solidifying and melting characteristics of the PCM utilised in the Li-ion cell battery module. Since PCM has low thermal conduction, thermal improvement techniques were investigated by inserting the copper plate into the PCM mixtures to boost the thermal conduction. PCM combination 50 : 50 is capable of holding battery running temperature compared to PCM combination 60 : 40. PCM combination 50 : 50 evidences to be ideal and lowered the operating temperature of the battery pack to 47°C.

Experimental study of lithium-ion battery cooling using mixture of phase change materials

Experimental study of lithium-ion battery cooling using mixture of phase change materials

Investigation of a binary eutectic mixture of phase change material for building integrated photovoltaic (BIPV) system

The incorporation of phase change material (PCM) into the building integrated semi-transparent photovoltaic (BISTPV) system is a promising technology to regulate the enhanced surface temperature of the photovoltaic (PV) system. In this work, Sodium Sulfate Decahydrate (Na2SO4·10H2O) and Zinc Nitrate Hexahydrate (N2O6Zn·6H2O) were mixed to form the binary eutectic PCM by heating mixing method. The results of Differential Scanning Calorimeter (DSC) characterization of those eutectic mixtures showed that the molar mass proportion of 70% weight of Na2SO4·10H2O and 30% weight N2O6Zn·6H2O was an optimum eutectic mixture for the solar energy applications. The developed eutectic mixture was employed in the specially designed and fabricated building-integrated semi-transparent photovoltaic phase change material (BISTPV-PCM) system to regulate BISTPV cell temperature. The experimentation was carried out at the outdoor environmental conditions in the region of Kovilpatti (9°10′0″N, 77°52′0″E), Tamilnadu, India throughout the year of 2018. The instantaneous peak temperature was reduced up to 12 ᵒC for the BISTPV-PCM system compared to the non-PCM counterpart. The annual output power generated from the BISTPV module was 34,287 W h/year which increased to 37,024 W h/year by using PCM.

Thermal stability enhancement of d-mannitol for latent heat storage applications

Phase change materials (PCM) are suitable to store high thermal energy densities in narrow temperature ranges due to the phase change from solid to liquid. Sugar alcohols are potential PCMs in the temperature range between 100 °C and 250 °C. Their melting enthalpy is higher than the one of most other PCMs, but their latent heat tends to degrade when heated above the melting temperature. In the present study, degradation rates of the sugar alcohol d-mannitol at three temperatures above the melting temperature are examined and strategies to enhance its thermal stability are demonstrated. These are the use of an antioxidant and the exposure to an inert atmosphere.The degradation shows the highest rate for pure d-mannitol under air and the lowest one for a mixture of PCM and antioxidant under argon. The thermal stability of pure d-mannitol under argon is higher than the one for a mixture of d-mannitol and antioxidants under air. The use of antioxidants and argon or their combination yield to an improved stability compared to pure d-mannitol under air, but cannot stop the degradation completely under the performed conditions.

Binary and Ternary Mixtures of Eicosane with Fatty Alcohols and Fatty Acids as Phase Change Material for Building Applications

Stable phase change materials (PCMS ) of binary and ternary mixtures of organic compounds were prepared in this work to be installed in buildings for purposes of heat energy storage. Binary mixtures of PCMS as salt hydrates, paraffins were heavily investigated but most of the mixing was within the same group very few articles deal with mixing PCMS from different organic groups or mixing more than two materials. A preparation and a differential scanning calorimetry ( DSC) investigation of binary and ternary mixtures of eicosane with fatty alcohols and fatty acids were performed. The eutectic mixtures of the binary systems were determined to be( 70% eicosane – 30% cetyl alcohol ) , (50% eicosane – 50% lauric acid) and (25% eicosane – 75% capric acid ) with melting temperature and latent heat of ( 33.77 ºC , 237.6 J/g ) , ( 30.63 ºC , 207.7 J/g ) and ( 24.96 ºC , 200.3 J/g ) respectively . The last one is very suitable for building applications. An eutectic mixture of eicosane with myristyl alcohol from previous work was considered as a new material and used to prepare two ternary mixtures( for the first time in literature) with both Cetyl Alcohol and Capric acid . An exciting results of temperatures were obtained : 26.86 ºC for the first ternary mixture and 16.23 ºC for the second one with moderate latent heats of 133.5 J/g and 157.7 J/g. The first one is very suitable for building applications and the second one is suitable for low thermal applications .These results will open the door to try ternary mixtures of common phase change materials to obtain various melting temperatures to suit different applications