E-Mail Alert

Add your e-mail address to receive forthcoming issues of this journal:

Journal Browser

Journal Browser

Special Issue "Phase Change Materials"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Materials Chemistry".

Deadline for manuscript submissions: 30 November 2019.

Special Issue Editor

Guest Editor
Dr. Ana Ines Fernandez Renna

Materials Science and Physical Chemistry, Universtat de Barcelona, Marti Franques 1, 08028 Barcelona, Spain
Website | E-Mail
Interests: material characterization; materials; nanomaterials; mechanical properties; polymers; materials engineering; polymerization; composites; renewable energy; chemical engineering; environmental engineering; nanocomposites; DSC; energy storage; thermal properties; plastics; polymer composites; magnesium; rubber; flame retardants

Special Issue Information

Dear Colleagues,

Phase change materials (PCMs) are key materials for latent heat energy storage. Thermal energy storage (TES) technologies have been identified as key enabling technologies to increase energy efficiency. However, TES systems based on PCM require more research in order to improve their performance. Several issues related to PCM properties should be addressed. While thermal properties such as latent heat are the main criteria for PCM selection, other characteristics should be further investigated and improved for its implementation. The enhancement of thermal conductivity and leakage prevention by encapsulation or the design of shape-stabilized PCMs are currently areas of high interest in the research. Others, such as thermal cycling stability, chemical stability, flammability and fire properties, low vapor pressure, and health-related issues are not as well-studied. This Special Issue aims at gathering the best papers on the development, improvement, and enhancement of PCMs.

Dr. Ana Ines Fernandez Renna
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • phase change materials (PCMs)
  • thermophysical characterization
  • standard methods
  • chemical stability

Published Papers (14 papers)

View options order results:
result details:
Displaying articles 1-14
Export citation of selected articles as:

Research

Jump to: Review

Open AccessArticle
Epoxy–PCM Composites with Nanocarbons or Multidimensional Boron Nitride as Heat Flow Enhancers
Molecules 2019, 24(10), 1883; https://doi.org/10.3390/molecules24101883
Received: 30 April 2019 / Revised: 13 May 2019 / Accepted: 15 May 2019 / Published: 16 May 2019
PDF Full-text (4119 KB) | HTML Full-text | XML Full-text
Abstract
The need for affordable systems that are capable of regulating the temperature of living or storage spaces has increased the interest in exploring phase change materials (PCMs) for latent heat thermal energy storage (LHTES). This study investigates n-nonadecane (C19H40) [...] Read more.
The need for affordable systems that are capable of regulating the temperature of living or storage spaces has increased the interest in exploring phase change materials (PCMs) for latent heat thermal energy storage (LHTES). This study investigates n-nonadecane (C19H40) and n-eicosane (C20H42) as alkane hydrocarbons/paraffins for LHTES applications. An epoxy resin is used as the support matrix medium to mitigate paraffin leakage, and a thickening agent is utilized to suppress phase separation during the curing process. In order to enhance the thermal conductivity of the epoxy–paraffin composite, conductive agents including carbon nanofibers (CNFs), carbon nanotubes (CNTs), boron nitride (BN) microparticles, or boron nitride nanotubes (BNNTs) are incorporated in different gravimetric ratios. Enhancements in latent heat, thermal conductivity, and heat transfer are realized with the addition of the thermal fillers. The sample composition with 10 wt.% BN shows excellent reversibility upon extended heating–cooling cycles and adequate viscosity for template casting as well as direct three-dimensional (3D) printing on fabrics, demonstrating the feasibility for facile integration onto liners/containers for thermal regulation purposes. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Graphical abstract

Open AccessArticle
Excellent Temperature-Control Based on Reversible Thermochromic Materials for Light-Driven Phase Change Materials System
Molecules 2019, 24(8), 1623; https://doi.org/10.3390/molecules24081623
Received: 28 February 2019 / Revised: 22 April 2019 / Accepted: 23 April 2019 / Published: 24 April 2019
PDF Full-text (2545 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Light-driven phase change materials (PCMs) have received significant attention due to their capacity to convert visible light into thermal energy, storing it as latent heat. However, continuous photo-thermal conversion can cause the PCMs to reach high thermal equilibrium temperatures after phase transition. In [...] Read more.
Light-driven phase change materials (PCMs) have received significant attention due to their capacity to convert visible light into thermal energy, storing it as latent heat. However, continuous photo-thermal conversion can cause the PCMs to reach high thermal equilibrium temperatures after phase transition. In our study, a novel light-driven phase change material system with temperature-control properties was constructed using a thermochromic compound. Thermochromic phase change materials (TC-PCMs) were prepared by introducing 2-anilino-6-dibutylamino-3-methylfluoran (ODB-2) and bisphenol A (BPA) into 1-hexadecanol (1-HD) in various proportions. Photo-thermal conversion performance was investigated with solar radiation (low power of 0.09 W/cm2) and a xenon lamp (at a high power of 0.14 W/cm2). The TC-PCMs showed a low equilibrium temperature due to variations in absorbance. Specifically, the temperature of TC-PCM180 (ODB-2, bisphenol A and 1-HD ratio 1:2:180) could stabilize at 54 °C approximately. TC-PCMs exhibited reversibility and repeatability after 20 irradiation and cooling cycles. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Figure 1

Open AccessArticle
Stearic Acid/Inorganic Porous Matrix Phase Change Composite for Hot Water Systems
Molecules 2019, 24(8), 1482; https://doi.org/10.3390/molecules24081482
Received: 19 March 2019 / Revised: 12 April 2019 / Accepted: 14 April 2019 / Published: 15 April 2019
PDF Full-text (5783 KB) | HTML Full-text | XML Full-text
Abstract
The storage and utilization of waste heat in low and medium temperature ranges using phase change materials (PCMs) is an effective technology to improve energy utilization efficiency in combined cooling, heating, and power (CCHP) systems. In this paper, stearic acid/inorganic porous matrix phase [...] Read more.
The storage and utilization of waste heat in low and medium temperature ranges using phase change materials (PCMs) is an effective technology to improve energy utilization efficiency in combined cooling, heating, and power (CCHP) systems. In this paper, stearic acid/inorganic porous matrix phase change composites were developed to store waste heat for hot water systems. Among them, stearic acid/expanded graphite (EG) phase change composite was highlighted and the thermal physical properties, the dynamic response, and the long-term cyclic stability were evaluated. The stearic acid concentrations in the composites were over 95 wt%. The thermal diffusion coefficients were 3–5 times higher than pure stearic acid, independent of composite densities. Accordingly, the heat storage and release times were decreased by up to 41% and 55%, respectively. After 100 cycles, the composites maintained good dynamic response and long-term cyclic stability, with heat storage density of 122–152 MJ/m3. Hence, this stearic acid/EG phase change composite exhibits excellent comprehensive performances. It is also easy to be prepared and flexible for various types of heat exchangers. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Figure 1

Open AccessArticle
Tests on Material Compatibility of Phase Change Materials and Selected Plastics
Molecules 2019, 24(7), 1398; https://doi.org/10.3390/molecules24071398
Received: 28 February 2019 / Revised: 5 April 2019 / Accepted: 8 April 2019 / Published: 10 April 2019
PDF Full-text (2722 KB) | HTML Full-text | XML Full-text
Abstract
Practical applications of Phase Change Materials (PCMs) often require their encapsulation in other materials, such as metals or plastics. This raises the issue of compatibility between PCMs and encapsulating materials, which has still not been sufficiently addressed. The study presented here follows existing [...] Read more.
Practical applications of Phase Change Materials (PCMs) often require their encapsulation in other materials, such as metals or plastics. This raises the issue of compatibility between PCMs and encapsulating materials, which has still not been sufficiently addressed. The study presented here follows existing research and provides experimental evaluation of the suitability of selected PCMs for proposed integration in building structures. Two organic PCMs, two inorganic PCMs and three representative plastics (polypropylene (PP-H), high density polyethylene (PE-HD) and polyvinylchloride (PVC-U)) were selected for compatibility tests. Evaluation of the results is based on the mass variations of the plastic samples during the test period. Plastic samples were immersed in PCMs and subjected to periodic heating and cooling (for 16 weeks) in a small environmental chamber simulating real operational conditions. The results show that the organic PCMs have a greater ability to penetrate the PE-HD and PP-H compared with the inorganic PCMs. The penetration of all PCMs was most notable during the first four weeks of the experiment. Later it slowed down significantly. Overall, the mass changes in PE-HD and PP-H samples did not exceed 6.9% when immersed in organic PCMs and 1.8% in inorganic PCMs. PVC-U samples exhibited almost negligible (less than 0.1%) mass variation in all cases. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Figure 1

Open AccessFeature PaperArticle
Corrosion Assessment of Myo-Inositol Sugar Alcohol as a Phase Change Material in Storage Systems Connected to Fresnel Solar Plants
Molecules 2019, 24(7), 1383; https://doi.org/10.3390/molecules24071383
Received: 27 February 2019 / Revised: 31 March 2019 / Accepted: 4 April 2019 / Published: 9 April 2019
PDF Full-text (7834 KB) | HTML Full-text | XML Full-text
Abstract
Thermal energy storage systems work in conjunction with solar technologies with the aim of increasing their dispatchability and competitiveness in the energy market. Among others, latent heat thermal energy storage systems have become an appealing research subject and many efforts have therefore been [...] Read more.
Thermal energy storage systems work in conjunction with solar technologies with the aim of increasing their dispatchability and competitiveness in the energy market. Among others, latent heat thermal energy storage systems have become an appealing research subject and many efforts have therefore been invested in selecting the best phase change material (PCM) to fit the final application. In this study, an extended corrosion characterization was performed for two PCM candidates, solar salt (40 wt.% KNO3/60 wt.% NaNO3) and myo-inositol (C6H12O6), to be applied in Fresnel solar plants. Corrosion rates were determined in aluminium, stainless steel (AISI 304), carbon steel (AISI 1090), and copper by gravimetric tests, gauging the weight loss after 2000 h of immersion at 250 °C. The corrosion products were characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD). The corrosion tests carried out with myo-inositol did not show accurate enough results to draw conclusions regarding corrosion on the metals. However, it was observed that this sugar alcohol strongly sticks to the metal specimens, making myo-inositol extremely difficult to manage as an energy storage material. Therefore, the present paper discourages the use of myo-inositol as a PCM beyond its corrosion rate. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Figure 1

Open AccessArticle
Investigation of the Role of Nano-Titanium on Corrosion and Thermal Performance of Structural Concrete with Macro-Encapsulated PCM
Molecules 2019, 24(7), 1360; https://doi.org/10.3390/molecules24071360
Received: 4 March 2019 / Revised: 28 March 2019 / Accepted: 4 April 2019 / Published: 6 April 2019
Cited by 4 | PDF Full-text (6873 KB) | HTML Full-text | XML Full-text
Abstract
The present study aims to investigate the impact of thermal energy storage aggregate (TESA) and nano-titanium (NT) on properties of structural concrete. TESA was made of scoria encapsulated with phase change materials (PCMs). Coarse aggregates were replaced by TESA at 100% by volume [...] Read more.
The present study aims to investigate the impact of thermal energy storage aggregate (TESA) and nano-titanium (NT) on properties of structural concrete. TESA was made of scoria encapsulated with phase change materials (PCMs). Coarse aggregates were replaced by TESA at 100% by volume of aggregate and NT was added at 5% by weight of cement. Compressive strength, probability of corrosion, thermal performance, and microstructure properties were studied. The results indicated that the presence of TESA reduced the compressive strength of concrete, although the strength was still high enough to be used as structural concrete. The use of TESA significantly improved the thermal performance of concrete, and slightly improved the resistance of corrosion in concrete. The thermal test results showed that TESA concrete reduces the peak temperature by 2 °C compared to the control. The addition of NT changed the microstructure of concrete, which resulted in higher compressive strength. Additionally, the use of NT further enhanced the thermal performance of TESA concrete by reducing the probability of corrosion remarkably. These results confirmed the crucial role of NT in improving the permeability and the thermal conductivity of mixtures containing PCM. In other words, the charging and discharging of TESA was enhanced with the presence of NT in the mixture. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Figure 1

Open AccessArticle
Analysis of the Thermal Storage Performance of a Radiant Floor Heating System with a PCM
Molecules 2019, 24(7), 1352; https://doi.org/10.3390/molecules24071352
Received: 28 February 2019 / Revised: 28 March 2019 / Accepted: 2 April 2019 / Published: 5 April 2019
PDF Full-text (3607 KB) | HTML Full-text | XML Full-text
Abstract
This study first reviewed previous studies on floor heating systems based on the installation of a phase change material (PCM) and the current status of technical developments and found that PCM-based research is still in its infancy. In particular, the improvement of floor [...] Read more.
This study first reviewed previous studies on floor heating systems based on the installation of a phase change material (PCM) and the current status of technical developments and found that PCM-based research is still in its infancy. In particular, the improvement of floor heat storage performance in indoor environments by combining a PCM with existing floor structures has not been subject to previous research. Thus, a PCM-based radiant floor heating system that utilizes hot water as a heat source and can be used in conjunction with the widespread wet construction method can be considered novel. This study found the most suitable PCM melting temperature for the proposed PCM-based radiant floor heating system ranged from approximately 35 °C to 45 °C for a floor thickness of 70 mm and a PCM thickness of 10 mm. Mock-up test results, which aimed to assess the performance of the radiant floor heating system with and without the PCM, revealed that the PCM-based room was able to maintain a temperature that was 0.2 °C higher than that of the room without the PCM. This was due to the rise in temperature caused by the PCM’s heat storage capacity and the emission of waste heat that was otherwise lost to the underside of the hot water pipe when the PCM was not present. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Figure 1

Open AccessArticle
Investigation of Lactones as Innovative Bio-Sourced Phase Change Materials for Latent Heat Storage
Molecules 2019, 24(7), 1300; https://doi.org/10.3390/molecules24071300
Received: 28 February 2019 / Revised: 25 March 2019 / Accepted: 28 March 2019 / Published: 3 April 2019
PDF Full-text (1549 KB) | HTML Full-text | XML Full-text
Abstract
In the presented work, five bio-based and bio-degradable cyclic esters, i.e. lactones, have been investigated as possible phase change materials for applications in latent heat storage systems. Commercial natural lactones such as ε-caprolactone and γ-valerolactone were easily purchased through chemical suppliers, while 1,2-campholide, [...] Read more.
In the presented work, five bio-based and bio-degradable cyclic esters, i.e. lactones, have been investigated as possible phase change materials for applications in latent heat storage systems. Commercial natural lactones such as ε-caprolactone and γ-valerolactone were easily purchased through chemical suppliers, while 1,2-campholide, oxa-adamantanone and dibenzochromen-6-one were synthesized through Baeyer-Villiger oxidation. The compounds were characterized with respect to attenuated total reflectance spectroscopy and gas chromatography coupled with mass spectroscopy, in order to confirm their chemical structures and identity. Subsequently, thermogravimetric analysis and differential scanning calorimetry were used to measure the phase change temperatures, enthalpies of fusion, degradation temperatures, as well to estimate the degree of supercooling. The lactones showed a wide range of phase change temperatures from −40 °C to 290 °C, making them a high interest for both low and high temperature latent heat storage applications, given the lack of organic phase change materials covering phase change temperature ranges below 0 °C and above 80 °C. However, low enthalpies of fusion, high degrees of supercooling and thermal degradations at low temperatures were registered for all samples, rendering them unsuitable as phase change materials. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Figure 1

Open AccessArticle
Effects of Pressure-Induced Density Changes in the Thermal Energy Absorbed by a Micro-Encapsulated Phase-Change Material
Molecules 2019, 24(7), 1254; https://doi.org/10.3390/molecules24071254
Received: 22 February 2019 / Revised: 21 March 2019 / Accepted: 22 March 2019 / Published: 30 March 2019
PDF Full-text (10820 KB) | HTML Full-text | XML Full-text
Abstract
Density changes produced by pressure increments during melting of a spherically confined phase-change material have an impact on the thermal energy absorbed by the heat storage unit. Several authors have assumed incompressible phases to estimate the volume change of the phase-change material and [...] Read more.
Density changes produced by pressure increments during melting of a spherically confined phase-change material have an impact on the thermal energy absorbed by the heat storage unit. Several authors have assumed incompressible phases to estimate the volume change of the phase-change material and the thermal balance at the liquid–solid interface. This assumption simplifies the problem but neglects the contribution of density changes to the thermal energy absorbed. In this work, a thermal balance at the interface that depends on the rate of change of the densities and on the shape of the container is found by imposing total mass conservation. The rigidity of the container is tuned through the coupling constant of an array of springs surrounding the phase-change material. This way, the behavior of the system can be probed from the isobaric to the isochoric regimes. The sensible and latent heat absorbed during the melting process are obtained by solving the proposed model through numerical and semi-analytical methods. Comparing the predictions obtained through our model, it is found that even for moderate pressures, the absorbed thermal energy predicted by other authors can be significantly overestimated. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Figure 1

Open AccessArticle
Own-Synthetize Nanoparticles to Develop Nano-Enhanced Phase Change Materials (NEPCM) to Improve the Energy Efficiency in Buildings
Molecules 2019, 24(7), 1232; https://doi.org/10.3390/molecules24071232
Received: 21 February 2019 / Revised: 20 March 2019 / Accepted: 23 March 2019 / Published: 29 March 2019
PDF Full-text (3167 KB) | HTML Full-text | XML Full-text
Abstract
The use of adequate thermal energy storage (TES) systems is an opportunity to increase energy efficiency in the building sector, and so decrease both commercial and residential energy consumptions. Nano-enhanced phase change materials (NEPCM) have attracted attention to address one of the crucial [...] Read more.
The use of adequate thermal energy storage (TES) systems is an opportunity to increase energy efficiency in the building sector, and so decrease both commercial and residential energy consumptions. Nano-enhanced phase change materials (NEPCM) have attracted attention to address one of the crucial barriers (i.e. low thermal conductivity) to the adoption of phase change materials (PCM) in this sector. In the present study two PCM based on fatty acids, capric and palmitic acid, were nano-enhanced with low contents (1.0 wt.%, 1.5 wt.% and 3.0 wt.%) of copper (II) oxide (CuO) nanoparticles. Copper (II) oxide (CuO) was synthesized via coprecipitation method obtaining 60–120 nm diameter sized nanoparticles. Thermal stability and high thermal conductivity were observed for the nano-enhanced phase change materials (NEPCM) obtained. Experimental results revealed remarkable increments in NEPCM thermal conductivity, for instance palmitic acid thermal conductivity was increased up to 60% with the addition of 3 wt.% CuO nanoparticles. Moreover, CuO nanoparticles sedimentation velocity decreases when increasing its content. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Figure 1

Open AccessArticle
Recycled Polyethylene/Paraffin Wax/Expanded Graphite Based Heat Absorbers for Thermal Energy Storage: An Artificial Aging Study
Molecules 2019, 24(7), 1217; https://doi.org/10.3390/molecules24071217
Received: 11 February 2019 / Revised: 18 March 2019 / Accepted: 21 March 2019 / Published: 28 March 2019
PDF Full-text (2029 KB) | HTML Full-text | XML Full-text
Abstract
An artificial aging study of novel heat absorbers based on phase change materials (PCMs) prepared from recycled high-density polyethylene (HDPE), paraffin wax (PW), and expanded graphite (EG) was investigated. The optimal composition of PCMs contained 40 wt% HDPE, whereas the paraffin wax content [...] Read more.
An artificial aging study of novel heat absorbers based on phase change materials (PCMs) prepared from recycled high-density polyethylene (HDPE), paraffin wax (PW), and expanded graphite (EG) was investigated. The optimal composition of PCMs contained 40 wt% HDPE, whereas the paraffin wax content ranged from 40 to 60 wt% and the expanded graphite content ranged from 5 to 15 wt%. PCMs were artificially aged through exposure to UV irradiation, enhanced temperature, and humidity. It was clearly demonstrated that the addition of EG to PCMs led to the suppression of PW leakage and improved the photooxidation stability of the PCMs during the aging process. The best performance was achieved by adding 15 wt% of EG to the PCMs. The sample shows a leakage of paraffin wax below 10%, retaining a melting enthalpy of PW within PCMs of 54.8 J/g, a thermal conductivity of 1.64 W/mK and the lowest photooxidation, characterized by an increase in the concentration of carbonyl groups from all investigated materials after artificial aging. Furthermore, PCMs mixed with EG exhibited good mechanical properties, even after 100 days of exposure to artificial aging. Finally, this work demonstrates a justification for the use of recycled plastics in the formation of PCMs. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Figure 1

Open AccessArticle
A Smart Epoxy Composite Based on Phase Change Microcapsules: Preparation, Microstructure, Thermal and Dynamic Mechanical Performances
Molecules 2019, 24(5), 916; https://doi.org/10.3390/molecules24050916
Received: 6 January 2019 / Revised: 24 February 2019 / Accepted: 1 March 2019 / Published: 6 March 2019
PDF Full-text (7665 KB) | HTML Full-text | XML Full-text
Abstract
Microencapsulated phase change materials (MicroPCMs)-incorporated in epoxy composites have drawn increasing interest due to their promising application potential in the fields of thermal energy storage and temperature regulation. However, the study on the effect of MicroPCMs on their microstructure, thermal and viscoelastic properties [...] Read more.
Microencapsulated phase change materials (MicroPCMs)-incorporated in epoxy composites have drawn increasing interest due to their promising application potential in the fields of thermal energy storage and temperature regulation. However, the study on the effect of MicroPCMs on their microstructure, thermal and viscoelastic properties is quite limited. Herein, a new type of smart epoxy composite incorporated with polyurea (PU)-shelled MicroPCMs was fabricated via solution casting method. Field emission-scanning electron microscope (FE-SEM) images revealed that the MicroPCMs were uniformly distributed in the epoxy matrix. The thermal stabilities, conductivities, phase change properties, and dynamic mechanical behaviors of the composite were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), thermal constant analyzer and infrared thermography. The results suggested that the heat storage ability of the composites was improved by increasing the MicroPCMs content. The thermal stability of MicroPCMs was found to be enhanced after incorporation into the matrix, and the MicroPCMs-incorporated epoxy composites showed a good thermal cycling reliability. Moreover, the incorporation of MicroPCMs reduced the composites’ storage modulus but increased the glass transition temperature (Tg) as a result of their restriction to the chain motion of epoxy resin. Besides, a less marked heating effect for the composite was explored through infrared thermography analysis, demonstrating the good prospect for temperature regulation application. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Figure 1

Open AccessArticle
Compounding MgCl2·6H2O with NH4Al(SO4)2·12H2O or KAl(SO4)2·12H2O to Obtain Binary Hydrated Salts as High-Performance Phase Change Materials
Molecules 2019, 24(2), 363; https://doi.org/10.3390/molecules24020363
Received: 21 December 2018 / Revised: 19 January 2019 / Accepted: 19 January 2019 / Published: 21 January 2019
Cited by 2 | PDF Full-text (5885 KB) | HTML Full-text | XML Full-text
Abstract
Developing phase change materials (PCMs) with suitable phase change temperatures and high latent heat is of great significance for accelerating the development of latent heat storage technology to be applied in solar water heating (SWH) systems. The phase change performances of two mixtures, [...] Read more.
Developing phase change materials (PCMs) with suitable phase change temperatures and high latent heat is of great significance for accelerating the development of latent heat storage technology to be applied in solar water heating (SWH) systems. The phase change performances of two mixtures, NH4Al(SO4)2·12H2O-MgCl2·6H2O (mixture-A) and KAl(SO4)2·12H2O-MgCl2·6H2O (mixture-B), were investigated in this paper. Based on the DSC results, the optimum contents of MgCl2·6H2O in mixture-A and mixture-B were determined to be 30 wt%. It is found that the melting points of mixture-A (30 wt% MgCl2·6H2O) and mixture-B (30 wt% MgCl2·6H2O) are 64.15 °C and 60.15 °C, respectively, which are suitable for SWH systems. Moreover, two mixtures have high latent heat of up to 192.1 kJ/kg and 198.1 kJ/kg as well as exhibit little supercooling. After 200 cycles heating-cooling experiments, the deviations in melting point and melting enthalpy of mixture-A are only 1.51% and 1.20%, respectively. Furthermore, the XRD patterns before and after the cycling experiments show that mixture-A possesses good structure stability. These excellent thermal characteristics make mixture-A show great potential for SWH systems. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Figure 1

Review

Jump to: Research

Open AccessReview
Carbon-Filled Organic Phase-Change Materials for Thermal Energy Storage: A Review
Molecules 2019, 24(11), 2055; https://doi.org/10.3390/molecules24112055
Received: 15 April 2019 / Revised: 25 May 2019 / Accepted: 27 May 2019 / Published: 29 May 2019
PDF Full-text (3243 KB) | HTML Full-text | XML Full-text
Abstract
Phase-change materials (PCMs) are essential modern materials for storing thermal energy in the form of sensible and latent heat, which play important roles in the efficient use of waste heat and solar energy. In the development of PCM technology, many types of materials [...] Read more.
Phase-change materials (PCMs) are essential modern materials for storing thermal energy in the form of sensible and latent heat, which play important roles in the efficient use of waste heat and solar energy. In the development of PCM technology, many types of materials have been studied, including inorganic salt and salt hydrates and organic matter such as paraffin and fatty acids. Considerable research has focused on the relationship between the material structure and energy storage properties to understand the heat storage/emission mechanism involved in controlling the energy storage performance of materials. In this study, we review the application of various carbon-filled organic PCMs in the field of heat storage and describe the current state of this research. Full article
(This article belongs to the Special Issue Phase Change Materials)
Figures

Figure 1

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Author: Claudia Luhrs
Affiliation:Mechanical and Aerospace Engineering Department,Naval Postgraduate School,700 Dyer Road. Watkins Hall Rm. 305,Monterey, CA,USA
Title: Development of Epoxy-PCM composite formulations with BN or CNT as heat flow enhancers
Abstract: We employed nonadecane (with a transition temperature that peaks at 32 degrees C) as phase change material, epoxy resin as encasing media and boron nitride or carbon nanotubes as enhancers to optimize heat flows in the composites. We plan to introduce the fabrication protocols, the characterization of the products by DSC, TGA and SEM and introduce our efforts to 3D print the formulations. The materials developed can find application in temperature control of living or storage spaces.

Molecules EISSN 1420-3049 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top