Bio-based Phase Change Material Research Articles

Development of bio-based flexible phase change materials utilizing lauric acid for battery thermal management systems

Lithium-ion batteries, serving as the cornerstone of electric vehicles, generate significant thermal output during their operation. This underscores the imperative need for the implementation of an appropriate battery thermal management system (BTMS). Extensive attention has been directed towards thermal-induced flexible phase change material (FPCM) within the domain of BTMS. However, it is notable that the predominant choice in contemporary practice for FPCM in BTMS remains paraffin (PA)-based, sourced from petroleum origins. This study utilizes an environmentally friendly bio-based phase change material (PCM), lauric acid (LA), to fabricate FPCM. The FPCM is skillfully crafted through the incorporation of styrene-ethylene-propylene-styrene (SEPS) and expanded graphite (EG) as supporting materials, forming the LA/SEPS/EG composite phase change material (CPCM). The addition of EG increases the thermal conductivity of CPCM by 4.97 times and enhances the leakage resistance. Furthermore, comprehensive assessments were conducted to evaluate the thermal performance, thermally induced flexibility, heat storage, release characteristics, and cyclic stability of the fabricated FPCM. In the battery discharge tests conducted at 2C/3C/4C rates, the battery containing FPCM consistently maintained its maximum temperature below 50 °C, with a minimal temperature difference of <1 °C, showcasing excellent thermal management performance.

Mechanical and thermal properties of building mortars incorporating bio based phase change material

Mechanical and thermal properties of building mortars incorporating bio based phase change material

Bamboo-encapsulated bio-based PCM panel as thermal stabiliser for glamping in a highland area of Indonesia

Glamping has become an alternative to camping with a unique nature experience. However, maintaining the temperature and humidity for glamping tents in highland areas remains challenging. Thermal conditions inside a tent fluctuate more drastically than outdoors, affected by the outdoor conditions, leading to significantly higher temperatures inside the tent during daytime and lower temperatures during nighttime. This study investigates the performance of bamboo-encapsulated bio-based phase change materials (PCM) panels as thermal stabilisers inside glamping tents in highlands. For five cycles, the environmental factors were measured, including temperature and relative humidity (RH) inside glamping tents, with (Tent 1) and without PCM panels (Tent 0), and outdoors in a highland area in Indonesia. The measured temperature within the glamping tents was compared with the outdoor temperature, divided into four periods in the daytime (Periods A-D) and one in the nighttime (Period E). Additionally, response surface methodology was performed to understand the response of various factors influencing the performance of PCM panels. This study demonstrates that PCM panels substantially improve temperature control in glamping tents. During the daytime, bio-based PCM panels effectively maintained the indoor temperatures of Tent 1 up to 3.99 °C colder than Tent 0. In conclusion, this study highlights the significant impact of PCM panels in stabilising the temperature inside the glamping tent, which also affects RH.

Bio‐based phase change material for enhanced building energy efficiency: A study of beech and thermally modified beech wood for wall structures

AbstractThis study investigated the impregnation of beech and thermally modified beech (TMB) with a ternary mixture of capric acid, palmitic acid, and stearic acid as a bio‐based phase change material (BPCM). Finite element method (FEM) was used to complement the experimental analysis by providing new insights into computational methods for simulating the behavior of BPCMs in untreated and TMB. The analyzed specimens namely beech and TMB were impregnated with BPCM; the TMB achieved 54% weight percentage gain (WPG) while untreated beech got 37%. Accordingly, a greater increase in the latent heat was obtained for TMB up to 90 J/g, while for untreated beech with BPCM up to 75 J/g. Impregnated specimens absorbed less moisture at relative humidity of air above 50%, likely caused by the high uptake and hydrophobic nature of the BPCM. The study highlights the research gap in performing mathematical simulations on wood samples with BPCM using material thermal properties derived from differential scanning calorimetry or T‐History analysis. It shows that the direct use of these values for simulations leads to unacceptable outputs that result in high errors. The root mean square error for untreated and TMB samples impregnated with BPCM was in the range from 1.06 to 3.1 while that for untreated samples was in the range from 0.57 to 0.87, indicating that the main challenge in simulating and characterizing the samples is due to the interaction of the phase change material with the wood structure.

Numerical investigation of the integration of new bio-based PCM in building envelopes during the summer in Algerian cities

This paper investigates the integration of a new bio-based phase-change material (PCM) into walls to improve energy storage in buildings. Three PCMs with ecological and highly renewable properties, combined by blending local vegetable oils with purified beeswax are investigated. The numerical study, using the optimal sample, concentrated on representative Algerian cities over a three-month summer period. A COMSOL software model is developed to solve the non-linear equations governing the physical phenomena. The results indicate that the use of bio-based PCM significantly improves energy storage capacity in all the cities studied. The performance of bio-based PCM energy storage highly depends on the specific climatic conditions of each city. The optimal location of the PCM layer in the walls is determined for all cities. The PCM is decreasing the maximum temperature of the inner surface, with differences of 3.95 °C, 3.25 °C, 3.17 °C and 2.98 °C respectively for Bachar, Tamanrasset, Constantine and Annaba. Those results enable the use of the developed bio-based material for building walls.

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.

Toroidal tube latent heat exchanger: An experimental study

Concentric shell and tube latent heat exchangers integrated with phase change material (PCM) are widely used in many heat storage/transfer applications specially for building energy management due to their high energy storage density and fair simplicity in design. However, inadequate phase change in such systems reduces the thermal performance. The innovative geometric design is key in addressing this issue and accelerating the phase change process. The present work reports an experimental effort to investigate the progression of the melting process of PCM inside a novel design of toroidal tube embedded in the system as a shell and tube latent heat exchanger. The experimental setup consists of a toroidal enclosure filled with a bio-based PCM (i.e., coconut oil) and a constant temperature bath as a heat exchange environment. Digital images of melting progression and melting front at three different boundary temperatures (high, middle, and low temperature differences) are captured. Moreover, the time dependent temperature at a selected prob. point is also measured during the phase change process. As expected, decreasing temperature difference, decrease the melting rate, as the experiments show that the completed melting times are 20, 32, and 75 min for the high, middle, and low temperature differences. The melting front is sharper and more distinct to track for higher temperature differences as well. To observe the melting pattern and melting front inside the system (cross-sectional area of the tube) better, the melting progression in different selected times in a half-toroidal tube is also investigated. Furthermore, an extensive uncertainty analysis associated with measuring devices is reported.

Experimental study and gradient-based ensemble intelligent computing to investigate effect of ultrasound on rheological behavior of bio-based phase change materials

The influence of ultrasound on the rheological behavior of new phase change material (PCM) is investigated. The PCMs are made from natural biological materials containing silicon carbide (SiC) nanoparticles or expanded graphite (EG) powders with weight fractions of 0, 0.05, 0.1, and 0.2 %. The rheological behavior of PCM composites is tested by a rheometer with shear rates of 10 up to 250 rpm. Surveys showed the smallest PCMs' viscosity at shear rates over 100 rpm is obtained for the highest sonication time. Results depict an ignorable change in the dynamic viscosity of PCMs with shear rate, and the shear thinning behavior reduces the PCMs' viscosity by raising the shear rate by 10–140 rpm. Results for EG/PCM and SiC/PCM composites showed non-Newtonian behavior at low shear rates. However, steadiness in viscosity at a shear rate higher than 140 rpm is observed for the Newtonian behavior of PCMs. The other outstanding consequence of this study is the development of novel robust machine learning, namely CatBoost, to simulate the rheological behavior of understudy nano-PCMs based on the weight fraction, sonication time, and shear rate. The multigene genetic programming (MGGP) as a comparative model is adopted to validate the primary model and provide a relationship for estimating the viscosity of each nano-PCMs. Simulation results revealed the superiority of the CatBoost (PCM-EG: R = 0.978 and RMSE = 1.739 mPa·s; PCM-SiC: R = 0.996 and RMSE = 0.374 mPa·s) to the MGGP (PCM-EG: R = 0.967 and RMSE = 2.103 mPa·s; PCM-SiC: R = 0.992 and RMSE = 2.368) in PCM composites.

Experimental analysis of a commercial size bio-based latent thermal energy storage for air conditioning

Future smart and efficient energy management systems for space cooling and heating in building applications require novel solutions to store heat to decouple the energy demand and the availability of renewable energy sources. Latent thermal energy storages represent one of the most promising solutions; however, their cost-effective implementation in terms of energy and cost savings and payback time needs to be verified case by case. Thus, simplified, though accurate, performance correlations during both charging and discharging phases are strongly needed to be implemented into the different dynamic simulation tools. This work is intended to present the experimental behavior of a novel 18 kWh latent thermal energy storage that uses the roll-bond technology to efficiently store and release cold energy by exploiting the solid/liquid phase change process of 300 kg of a biobased phase change material having a melting temperature of 9 °C. The effects of the inlet water temperature and flow rate are studied to elucidate how the performance varies and to identify possible control strategies. On the basis of the experimental results, two correlations are proposed to accurately predict the performance of the latent thermal energy storage to be implemented in general dynamic simulation tools that can help in evaluating the system performance and the achievable energy and cost savings.

A Systematic Review on Bio-Based Phase Change Materials

Global warming and energy depletion are the main problems faced in recent years due to energy consumption by industries and the global population. Phase change materials (PCMs) with significant properties tend to store and release energy and fill the demand and supply gap. Most organic and inorganic PCMs are not considered environmentally eco-friendly when used for thermal energy storage (TES). Because they are formed from non-conventional energy resources, their carbon footmark and environmental effect are not ignored. To reduce problems, an urgent need for eco-friendly materials is required. Green substitute bio-based phase change materials (BPCMs) have gained extensive attention and are considered the best suitable replacement for organic and inorganic PCMs because BPCMs exhibit significant properties that are cost-effective, eco-friendly, renewable and convenient for thermal energy storage. However, the thermal conductivity of BPCMs is too low, which delays TES and heat transfer rates. Furthermore, this paper summarizes the reduction of low thermal conductivity problems with the help of highly conductive nanoparticles dispersed into the BPCMs and the fabrication methods of BPCMs composites. This article also provides information for futuristic researchers about the methods of fabrication and factors for enhancing the thermal conductivity of an eco-friendly BPCM composite and draws an important conclusion from the literature.

Can vegetable oils be used as sustainable phase change materials for thermal energy storage in building?

In a context where the need to reduce the carbon footprint of the building sector is increasingly pressing, this article looks at the potential application of vegetable oils as biobased phase change materials (PCM), offering a sustainable alternative to often harmful petrochemical products. The first part of our work detailed the different sources of production of vegetable oils worldwide. Secondly, the chemical characteristics of 45 vegetable oils were analyzed to propose their classification according to the average number of unsaturations (ANU) per fatty acid. Then, differential scanning calorimetry (DSC) was used to characterize the thermal properties of these vegetable oils, especially during their change of solid-liquid state. These measurements led to the precise determination of the melting and crystallization temperatures and the associated enthalpies. These characteristics, which vary from one vegetable oil to another, were discussed considering the structural information previously established. Then, determining which plant oils were most suitable for PCM functions in various application areas was possible. The materials identified in this paper have the advantage of being useable in many different countries and at reduced costs.

Economics and lifecycle carbon assessment of coconut oil as an alternative to paraffin phase change materials in North America

Globally, almost 40% of carbon emissions are attributable to building operation and embodied carbon. Phase change materials (PCMs) can store solar energy during peak periods to decrease summer cooling loads and overnight winter heating loads and emissions. At present, most PCMs are non-renewable paraffins with high embodied carbon; plant-based oils such as coconut oil may maintain the conditioning load reductions, while reducing the sustainability and embodied carbon of PCMs. The objective of this study was to determine the economic and emissions of coconut oil as an alternative to paraffins via full house simulations in three North American locations within different climate zones. It was found that paraffin PCM had greater embodied carbon and annual heating and cooling reductions than the coconut oil, causing the lifecycle carbon footprint to be lower with paraffin PCM than with the coconut oil over the house lifetime. This indicates the importance of developing bio-based PCMs with latent heat capacity that more closely compare to paraffins, in order to minimize total building carbon footprint. It was also found that the economic payback period of both PCMs may exceed the lifetime of the house and thus render the PCMs infeasible without reductions in capital costs or increased carbon pricing.

Effect on the Thermal Performance of a Bio-based Phase Change Material with the Addition of Graphite with Surfactants

This work presents an experimental investigation into how adding graphite with different surfactants to a bio-based phase change material (PCM) affects its cooling performance. Graphite-based phase change materials (GraPCMs) are prepared by stirring and sonicating graphite with different surfactants, including Sodium Stearoyl Lactylate, Sodium Dodecylbenzene Sulfonate (SDBS), and Sodium Dodecyl Sulfate (SDS), in a liquid bio-based PCM. Based on the experiments, the thermal conductivity of the bio-based PCM is increased by 240% to 0.748 W/m⋅K and 218% to 0.70 W/m⋅K when mixed with graphite-SDBS and graphite-SDS, respectively, at a 5% mass fraction of graphite. The ratio of 1:3 graphite to surfactant at a 5% mass fraction of graphite results in the longest amount of time for GraPCM-SDBS and GraPCM-SDS to reach the reference temperature of 43 °C, with delays of 185 and 175 s, respectively. It is observed that increasing the concentration of surfactant leads to further delay in reaching the reference temperature in the case of GraPCM-SDS. The results agree with the literature, as the surfactants and graphite enhanced the thermal conductivity of the PCM.

Development of a new lightweight gypsum composite: Effect of mixed treatment of barley straws with hot water and bio-based phase change material on the thermo-mechanical properties

Regenerative construction currently enables the development of regenerative composites intended for the thermal rehabilitation of outside walls. The composite studied is the gypsum lightened by barley straws treated with hot water (BS.HW) and then treated with the bio-based phase change material (palm oil (PO)). The aim is to improve the thermophysical properties of the composite studied. The results show that the new lightweight gypsum composite with the ratio 2.6:1 of (PO:BS.HW.3%) has improved the thermal diffusivity, with a reduction of 12.1% compared to the basic composition. The microstructural analysis results are also very interesting, especially considering the good chemical stability.

New hybrid bio-composite based on epoxidized linseed oil and wood particles hosting ethyl palmitate for energy storage in buildings

In this study, the incorporation of ethyl palmitate (EP) as a bio-based phase change material (BPCM) in wood particles, the preparation and properties of the novel biocomposite for building applications were investigated. The wood particle-based composites hosting BPCM were produced by cold compression moulding. The EP impregnation step was optimized in terms of uptake and its ratio by post-addition of non-impregnated fibers. The optimized wood particles/EP ratio were combined with 37.5% epoxidized linseed oil (ELO) as a binder to produce a composite with energy storage function containing more than 99% bio-ingredients. The optimum BPCM content in the composite was 25%. The produced biocomposites were characterized by T-hystory, DSC, TGA, and a moisture buffer test. The results revealed excellent moisture buffer values (2.07 g/m2 RH%) according to the Nordtest protocol, significant thermal mass, ability to store excessive energy in terms of latent heat and maintain the temperature constant for longer time, good thermal stability and improved specific heat capacity when compared to a reference composite without BPCM. The effect of incorporating BPCM into biocomposite for regulating temperature fluctuations was confirmed by comparing test prototype cubes, with and without BPCM, subjected to temperature fluctuation between 0 and 40 °C.

Biobased Phase Change Material with Reduced Thermal Conductivity: From Preparation to Analysis of Thermal Insulation Performance

Coaxial fiber membranes (CFMs) with poly(ethylene oxide) (PEO) encapsulated by biobased poly(L-lactic acid) (PLLA) were prepared by coaxial electrospinning technology, whose thermal management capacity was investigated. The coaxial structure and thermal reliability were studied by transmission electron microscopy, cycle-heating experiment, differential scanning calorimetry, thermogravimetric analysis, and wide-angle X-ray diffraction. Both heat conduction experiment and insulation experiment confirmed that the coaxial fibers have excellent thermal management capability. CFMs with PEO content of 49 wt % exhibit remarkable thermal stability and energy storage, while the thermal insulation efficiency could be improved by more than 21% comparing with a pure PLLA membrane. A Fourier equation corrected by the melting enthalpy of PEO can well describe the heating curves of CFMs, suggesting the primary and secondary effects from latent heat of PEO melting and reduced thermal conductivity of PLLA glass transition. The excellent thermal management capability and thermal stability underlies the wider application of CFMs.

Rheological, Spectroscopic, and Chemical Characterization of Asphalt Binders Modified with Phase Change Materials, Polymers, and Glass Powder

Recently, asphalt modifiers have increasingly gained attention for improving the mechanical and thermal characteristics of asphalt mixtures. As a result, innovative additives are being constantly developed to achieve this purpose. However, some modifiers can significantly impact the chemical and rheological properties of the asphalt binder. This paper investigates the rheological, spectroscopic, and chemical properties of asphalt binders modified with a bio-based phase change material (PCM) and phase change material mixed with glass powder (GPCM). Two binders were investigated, PG 58-28 and PG 70-28 polymer modified asphalt binder with 3% SBS. Two different percentages of GPCM (5% and 7%) were added to PG 58-28 and PG 70-28, and 5% PCM was added to PG 58-28. The results indicated that the PCMs effectively reduced the viscosity values of the asphalt binder. Moreover, testing the modified binders using differential scanning calorimetry (DSC) showed that the PCMs released the stored heat when the melting/freezing temperature was reached. However, adding glass powder with the PCMs negatively affected the thermal properties of PCMs in the asphalt mix. In addition, considerable changes in the stiffness of the binders modified with GPCM at an intermediate temperature were obtained when tested using DSR. Finally, the TGA results revealed that this specific type of PCM would not be suitable as a hot mix asphalt (HMA) modifier as its evaporation temperature is lower than the mixing temperature HMA. However, the use of PCM in warm mix asphalt (WMA) would be a more viable option. The results showed that the evaporation temperature for the PCMs was low; therefore, the PCMs cannot be used in HMA. In addition, modified binders with PCMs and GPCM showed lower viscosity compared to the control binder. The DSR rheological analysis showed that the control binder and 5%PCM, 5%GPCM, 7%GPCM, 5%GPCM, and 7%GPCM binders had similar overall properties. However, the addition of GPCM significantly decreases the stiffness at intermediate temperatures.

A novel bio-based phase change material of methyl palmitate and decanoic acid eutectic mixture: Thermodynamic modeling and thermal performance

One of the most sustainable methods of energy management is thermal energy storage using renewable phase change materials. Phase change materials (PCMs) with high latent heat can store thermal energy when available and release it effectively when required. In this study, the thermal properties of a set of binary mixtures of methyl palmitate (MP) and decanoic acid (DA) have been evaluated as a new bio-based and renewable PCM. Both phase change materials are obtained from vegetable oil and are biomass-based materials. The results show that the binary eutectic mixture consisting of 30% MP and 70% DA has the desired properties as a PCM for applying as thermal energy storage in the building materials. These features include the convenient melting and freezing temperatures (Tm = 20.19 °C, Tf = 15.08 °C) and the high value of corresponding latent heats (ΔHf =202.3 J.g−1, ΔHm = 201.43 J.g−1). Evaluating other thermo-physical properties of this mixture also confirms its fitness for the PCM role. The composition and melting point of the eutectic point and the solid-liquid phase equilibrium for these mixtures were predicted by several thermodynamic models from which UNIQUAC showed the lowest Average Relative Deviation percentage (ARD%) of 0.29%.

Impregnation of Norway spruce with low melting-point binary fatty acid as a phase-change material

Norway spruce was impregnated with a eutectic mixture of capric acid and stearic acid. The binary fatty acid was used as a bio-based phase-change material (PCM) for further applications with wood as a latent heat-storage material in building components. For this purpose, different concentrations of impregnation were evaluated. The weight-percentage gain of 124% was the highest for the pure fatty acid mixture, and the PCM-impregnated wood increased density from 470 kg/m³ (untreated wood) to 1045 kg/m³. Compressive strength and hardness were significantly elevated with higher content of fatty acids in the wood. Microscopy analysis confirmed the presence of the PCM within the wood cells. The treated wood also exhibited a larger time delay during heating and cooling due to the temperature shift in the phase transition. Depending on the concentration of the fatty acid in the wood, the latent heat during melting ranged from 50 to 125 J/g in the temperature from about 24°C to 30°C. These results suggest that the use of the capric acid and stearic acid mixture has a great potential to increase the heat-storage capacity of wood and reduce energy consumption for heating and cooling indoor spaces.

Microencapsulation of bio-based phase change materials with silica coated inorganic shell for thermal energy storage

This study investigates the use of cenospheres to encapsulate a low-cost, bio-based phase change material (PCM) derived from refined edible vegetable oil. Chemical etching was applied on the cenospheres to create holes through which melted PCM was loaded to produce a PCM microcapsule. Subsequently, a silica-based coating was applied to seal the perforations and prevent leakage of PCM from the microcapsule. Microstructural, chemical compatibility, thermal, and leakage properties of the produced silica coated PCM microcapsule (SCPCM) were assessed. No leakage was found for this new microcapsule, and higher thermal stability and conductivity were noted. Thermal decomposition of the PCM in SCPCM was delayed by about 16 °C attributable to the silica coating. An enhanced compressive strength performance was achieved at 10 vol% of sand replacement with SCPCM. 20–30 vol% replacement of sand with cenosphere microcapsules seems to be the optimal range for reasonable compressive strength. The workability of the mortar incorporated with SCPCM decreased when the replacement level increased to more than 30 vol% due to the hydrophilic nature of the silica deposit. This study has demonstrated the potential of cenospheres as inorganic shell for PCMs and the potential for incorporation of SCPCM into construction materials for thermal energy storage (TES).