Organic PCM Research Articles

Organic Phase Change Materials as Thermal Energy Storage for Automated Solar Seawater Desalination System

A prototype of an automated solar seawater desalination system equipped with thermal energy storage was designed and developed to analyze experimentally the effect of adding organic phase change materials (palm wax and beeswax) to the desalination system’s efficiency. The desalination machine was set up with two configurations: with organic and without organic PCMs. While the setup without a PCM can produce an average of 30.8 mL per day and convert 2.056% of the total volume of input water to an output peak of 48.5 mL using solar energy, the setup with a PCM can produce an average daily water production of 68.9 mL and convert 4.6% of the input water volume with the highest record output of 104.5 mL compared to configurations without PCM, the organic PCM system with a 1:1.2 mixture of beeswax and palm wax can produce an average of 123.7%.

An Experimental Study on the Thermal Performance of a Heat Sink Filled with Porous Aluminum Skeleton/Paraffin Composite Phase Change Material.

Organic phase change material is an ideal solution to solve the heat dissipation problem of electronic devices. However, its low thermal conductivity limits its application. To solve this problem, a new porous aluminum skeleton/paraffin composite phase change material (AS-PCM) was prepared. The effects of porosity and porous aluminum skeletons on temperature control performance were explored. The experimental results show that the addition of AS significantly improves the thermal conductivity of organic PCM, and the thermal conductivity of AS-PCM is 32.3-59.6 times higher than that of pure paraffin. In addition, the temperature difference in AS-PCM with 75% porosity is 1-2 °C lower than that of AS-PCM with 85%, and 5-8 °C lower than that of AS-PCM with 95% porosity. The skeleton structure has an impact on the temperature control performance. The Mcc porous aluminum skeleton/paraffin composite phase change material (MAS-PCM) yields the best thermal performance compared with the Fcc porous aluminum skeleton/paraffin composite phase change material (FAS-PCM). The temperature control time of the MAS-PCM heat sink is increased by 5.3-50.8% relative to the FAS-PCM heat sink. The research results provide a novel approach for improving the thermal conductivity of PCMs.

Eco‐friendly approach to thermal energy storage: Assessing the thermal and chemical properties of coconut biochar‐enhanced phase change material

AbstractPhase change materials (PCMs) can absorb, store, and release substantial latent heat within a specific temperature range during phase transition and have gained huge attention due to environmental concerns and energy crises. However, PCMs have a significant downside in energy storage due to their relatively lower thermal conductivity, leading to inadequate heat transfer (HT) performance. The foremost aim of the research is to synthesize an eco‐friendly coconut shell biochar (CSB) dispersed with organic A46 PCM in the temperature range of 44°C to 46°C to form a green nanocomposite. A two‐step approach is adopted to formulate the nanocomposites with different weight concentrations (0.2% and 0.8%) of green CSB particles. The developed nanocomposite's thermal conductivity and chemical stability were examined using a thermal properties analyzer and a Fourier transforms infrared spectrometer. The developed biochar composites have excellent thermal conductivity (0.39 W/m K) compared with base PCM (0.22 W/m K). Also, the developed nanocomposites were physically mixed together; there were no additional functional groups formed compared to pristine PCM, and the prepared materials were composite. Furthermore, a numerical analysis was performed using two‐dimensional energy modeling software to ascertain the HT rate of A46 composites. These thermally energized green nanocomposites show great promise for thermal energy storage and thermal management applications like battery thermal management, photovoltaic thermal systems, desalination systems, electronic cooling, building applications, and textiles.

Development and preparation of novel nano-enhanced organic eutectic phase change materials for low-temperature solar thermal applications

ABSTRACT Thermally reliable and stable eco-friendly Phase change materials are of significant aid in thermal energy storage technology, leading to improved energy utilization and reliability of the system. This study develops two novel organic eutectic PCM of Lauric acid – Margaric acid (LM) and Myristic acid – Margaric acid (MM), which are chemically stable and thermally compatible for latent heat energy storage. LM eutectic mixture had a melting temperature of 52.66°C with a latent heat of 163.68 J/g, and MM eutectic mixture had its melting temperature at 44.79°C and a latent heat of 197.31 J/g. The phase change temperatures were favorable for low temperature solar thermal applications with good latent heat capacity. The thermal characteristics of these eutectic mixtures are further enhanced with the dispersion of highly conductive Multi walled carbon nanotubes (MWCNT) at three different mass fractions (.5%, 1% and 1.5% by weight). Nano enhancement could achieve exceptional thermal conductivity enhancement in MM eutectic mixture by 110.6% and 83.73% in LM eutectic mixture. Thermogravimetric analysis and Fourier-transform infrared spectroscopy analysis ensured the thermal and chemical stability of the eutectic mixtures. The optical absorption characteristics were extensively enhanced with nano particle addition, which is highly preferable in solar thermal applications.

Experimental heat transfer analysis of the effects of thermophysical properties on PCM at freezing conditions employing Particle Image Velocimetry

Cold chain logistics of fresh produce distribution are facing new challenges owing to the increasing consumer demand, often traveling long distances, and facing temperature variations during storage and distribution stages. Nowadays, solutions for improving food preservation by searching effective energy storage strategies, such as the use of PCM, are capturing more interest. Nevertheless, most studies are focused on organic PCM with ambient temperature melting points analyses. This leaves an important research gap in the experimentation of other types of eutectic materials with melting points below 0 °C, something of great interest for food preservation in the refrigeration industry. Velocity vector field and heat transfer via natural convection in a small cavity filled with two different PCM at below 0 °C conditions were experimentally investigated employing temperature measurements and Particle Image Velocimetry. In this regard, brine (18.8 wt%) and ethylene glycol-water (EGW) blend (30.5 wt%) PCM with equal melting temperature, but different thermophysical properties, were selected to compare their thermal behavior. It was investigated the effects of thermophysical properties such as density, specific heat capacity, thermal conductivity, and viscosity on melting front, heat transfer and flow patterns through the evaluation of liquid fraction, heat storage, Nu, Gr, Ra, and velocity field. The maximum Nu value for brine was almost the double of that of EGW. Pr values of EGW were in average 1.88 times higher than those of brine. Besides, Gr and Ra values of brine were in average 7.23 and 3.97 higher than those of EGW, respectively.

Expanded graphite nanoparticles-based eutectic phase change materials for enhancement of thermal efficiency of pin–fin heat sink arrangement

This experimental work foresights the synthesis and characterization of the expanded graphite (EG) enhanced organic-organic eutectic PCM (EGePCM) with different weight percentages of the EG (ϕ = 1–5 %). In particular, the expanded graphite nanoparticles were exfoliated from the graphite flakes by acid protonation followed by extraction from the traditional co-precipitation synthesis. A series of EGePCM nanocomposites were fabricated through the homogeneous suspension of EG nanoparticles in the eutectic mixture (1:1) of organic PCM. The surface texture, physical morphology and chemical interaction of individual elements present inside the nanocomposites were thoroughly examined by FTIR, XRD, SEM, and FESEM. Conversely, the physical attributes, thermal stability, thermal degradation, and charging-discharging performance were also investigated. The EGePCM nanocomposite with 3 wt% of EG nanoparticles expresses a favourable increase of thermal conductivity by 232.24 %, with a nominal reduction in the latent heat storage capacity (176.5 J/g) of the PCM. In conjunction with the thermal attribute intensification, the incorporation of EG in nanocomposite reduces the supercooling degree to 9.16 °C with a phase change enthalpy of 174.8 J/g in cooling and 176.5 J/g in heating stage for 3 wt% of EG. A comprehensive experimental methodology was employed to investigate the thermal enactment features of different EGePCM nanocomposites inside a regular pin–fin arrangement imperilled with steady-state heat transfer. The effectiveness of the cooling rate was also encompassed under a variable range of heat flux (1.6–3.2 KW/m2) and EGePCM mixture (ϕ = 1–5 %). The heat transfer effectiveness was optimal at a mass fraction of 5 wt%, resulting in a 30 °C base temperature drop of the heat sink and a decrease in the charging-discharging duration of the nano PCM composite. This observation suggests an improvement in the thermal conductivity of the system with an incorporation of high thermal conductive EG nanoparticles. The enhanced thermal performance and notable thermal, physical and chemical stability facilitate the phase transition progression and render it highly advantageous for electronic or micro-electronic thermal cooling applications.

Numerical investigation on thermal performance of a solar greenhouse with synergetic energy release of short- and long-term PCM storage

To address the problem of low greenhouse temperature at late night in north China, a new strategy of synergetic release of short- and long-term PCM heat storage is proposed in this paper, i.e. supercooled salt hydrate units are activated to release seasonally stored latent heat after the organic PCM north wallboard with daily storage cannot provide the required indoor temperature. To achieve this strategy, a microclimate model considering multiple greenhouse elements, including solar radiation, crops, indoor air, water vapor, soil and PCMs, is developed and 3D computational fluid dynamic (CFD) simulations are employed to examine the thermal performances of this strategy under Beijing climate conditions. The results demonstrated that the new strategy promotes the greenhouse temperature suitable for tomato growth (15 °C) throughout the whole night in winter. The organic PCM (Tm = 25 °C) wallboard can reduce the daytime indoor temperature by 0.5–1.5 °C and increase the nighttime indoor temperature by 4–5.5 °C than without PCM wallboard on January 1st. But the greenhouse temperature with this single daily storage is still lower than the required 15 °C after 4:00 a.m. With consideration of the unit numbers and heating effects, triggering two supercooled sodium thiosulfate pentahydrate (STP) units at one time (rather than sodium acetate trihydrate (SAT) and calcium chloride hexahydrate (CCH)) is the reasonable choice for greenhouse heating under present conditions. The system can achieve synergetic energy release across seasons, days and nights, regulate the thermal environment in the greenhouse, and promote the quantity and quality of crop output.

Utilization of Small Solar-ORC Integrated with Organic PCMs in Hungary Condition

Regarding solar energy resource potential, Hungary has a daily total of around 3.2 to 3.6 kWh/m2 and an annual total of approximately 1168 to 1314 kWh/m2. It makes it a good position for solar thermal collectors in combination with an ORC system. In this study, the authors investigated solar thermal as a heat source to generate electricity, with ORC utilizing R245fa as a working fluid. Due to the limited time for utilizing solar thermal by ORC, while the highest electricity usage is at night, heat storage is carried out by integrating a TES-evaporator using organic PCM.

Investigation of 1-tetradecanol with functionalized multi-walled carbon nanotubes as PCM for high-density thermal energy storage

To evaluate a potential thermal battery material for thermal energy storage applications, this study prepared a stable organic nano-dispersed PCM (NDPCM) with 1-tetradecanol (TD) with a melting point and latent heat of 37.8 °C and 236.4 J/g, respectively, as base PCM and investigated its thermal properties. The high thermal conductive nano-additives of functionalized multi-walled carbon nanotubes (MWCNT-COOH) with a concentration range of 1 wt% to 5 wt% were infused in the pure PCM. As a result, MWCNT-COOH shows better dispersion stability. The SEM microimage confirms no agglomeration was observed for the prepared NDPCM. The supercooling was reduced from 10.6 °C for the pure TD to 7.7 °C for TD with 5 wt% of MWCNT. The latent heat of the NDPCM with 5 wt% MWCNT-COOH was 212.6 J/g with a 10% reduction compared to pure TD. The reduction in latent heat values is lower than the previously investigated TD composite PCM. The thermal stability study through gravimetric analysis confirms that the decomposition of the NDPCMs initiates at 200 °C, which will not be affected by thermal fluctuation in the system. The sample with 5 wt% of nano-additives had the most excellent thermal conductivity (TC) improvement, 56.2% in the liquid phase, whereas 50% in the solid phase. The reported values are significantly higher compared to the previous thermal conductivity improvement of TD using metallic nanoparticles. The prepared NDPCM shows better thermal properties than the pure PCM and can be a possible material for high-density thermal energy storage applications.

Environmental impact analysis of organic phase change materials for energy storage by using ReCiPe endpoint method

Today, phase change materials are often used in our daily lives. These organic components contain a variety of ingredients, A few have a greater impact on the environment than others. Organic PCM are a type of material that can be used for thermal energy storage applications. The purpose of this research is to look at how organic phase change materials affect the environment, allowing technologists to assess environmental factors. A mid - term evaluation approach was used to analyze the life cycle of organic PCM. One of the software Simapro 9.2 were used to develop the life cycle assessment, which was based on the lifecycle inventory Ecoinvent v3.4 data source. Environmental impact values ​​were quantified using the ReCiPe methodology and an extensive range of outcome are produced. There was a significant difference between the results obtained with EcoInvent organic PCM and the results obtained 82% with PCM. Analyzed organic PCMs are a global concern for the environment, because these substances have significant environmental consequences and their availability has expanded in recent centuries, which is a reason for anxiety in the global industry.

Preparation and Thermal Model of Tetradecane/Expanded Graphite and A Spiral Wavy Plate Cold Storage Tank

A cold storage unit can store the cold energy off-peak and release it for building cooling on-peak, which can reduce the electricity load of air conditioning systems. n-tetradecane is a suitable cold storage material for air conditioning, with a phase change temperature of is 4–8 °C and a phase change enthalpy of 200 kJ/kg. However, its low thermal conductivity limits the application of n-tetradecane for high-power cold storage/release. This paper prepares a tetradecane/expanded graphite (EG) composite phase change material (CPCM), whose thermal conductivity can be increased up to 21.0 W/m·K, nearly 100 times over the raw n-tetradecane. A novel model to predict the maximum loading fraction of paraffin in the EG matrix is presented, with an error within 1.7%. We also develop a thermal conductivity model to predict the thermal conductivity of the CPCM precisely, with an error of less than 10%. In addition, an innovative spiral wave plate cold storage tank has been designed for the tetradecane/EG composite. The power and energy density of the cold storage tank are significantly improved compared to that of raw tetradecane. The energy density reaches 40 kWh/m3, which is high among the organic PCM thermal storage tank. This paper shows the significance of thermal conductivity enhancement in designing a cold storage tank.

Effects of Hybrid Nanoparticles on Thermophysical Property of Cu-TiO2 Embedded Palmitic Phase Change Material for Energy Storage Applications

This experimental investigation studies the thermo physical effects of Cu-TiO2 hybrid nanoparticles embedded into organic PCM (palmitic acid) for energy storage applications. This Nano Embedded PCM (NEPCM) or Hybrid Nano composite (HNPCM) is used for heating, cooling and numerous energy storage applications. This hybrid nano composite mixture was synthesized by mixing different weight percentage Cu-TiO2 hybrid nanoparticles in palmitic acid. The dispersion is facilitated with the help of ultrasonicator. The hybrid nanoparticles were characterized with Scanning Electron Microscope. Fourier Transform Infrared spectroscopy analysis was used to determine the chemical stability and composition of composite mixture. LFA 467 flash diffusivity apparatus was used to measure the increase in thermal conductivity. The test results suggest that, by embedding HyNC into pure PCM. It has credited for achieving chemical stability, concurring phase transition temperature, favourable latent heat. HyNC particles have effectively enhanced the thermal conductivity of the PCMs by 52% without sacrificing chemical stability or thermal degradation. This result shows that the addition of HyNC into the palmitic acid increases the solidification and melting time, thus confirming the enhancement in thermal conductivity. This enhanced thermal characteristic makes HNPCM’s as a potential candidate for energy storage and heat transfer applications.

Size effect at discharging process of coconut oil as latent thermal energy storage

Coconut oil is one of the organic PCM materials with high thermal energy storage capability in the form of sensible and latent heat. Ideally, the latent heat storage occurs at a relatively constant temperature associated with phase change transition. Due to relatively low thermal conductivity, the size effect is important to optimize material performance, particularly at the discharging process related to latent heat release. This study will show the simulation results of the size effect in the solidification process of coconut oil by using ANSYS FLUENT. Three plastic balls with radii 2 cm, 3 cm, and 6 cm filled with coconut oil solidified from 308 K to 293 K, and several temperature detectors were placed in the ball to study the heat exchange process. The input parameters of density, heat capacity, thermal conductivity, and viscosity were taken from previous experimental studies. We reported the time evolution of temperature and liquid fraction until the molten coconut oil solidified from different detector positions in each ball.

Thermal Protection Performances of the Macro and/or Nano Enhanced PCM in a Representative Battery Pack

ABSTRACT This experimental study focused on the comparison of thermal protection performances of macro and/or nano enhanced organic PCM in a representative battery pack from low to high discharge rates. The macro/nano enhanced RT-44 provides the desired battery thermal protection requirements in terms of criteria such as maximum temperature and maximum temperature difference restriction and uniform temperature distribution throughout the battery pack. It increases the effective battery thermal protection time by 117%-32% depending on the discharge rates. While PCM thermal protection provides a more homogeneous temperature distribution throughout the battery pack, nano and/or macro enhanced one provides it throughout the cell. The macro enhancement essentially makes a major contribution to shortening the cooling time for the next use.

Investigating the single pass baffled solar air heater (SAH) with an organic PCM (OPCM)

The current work shows the results of an experimental assessment into the performance of a baffled solar based air heater (SAH-BP) with the organic phase changing material (OPCM) back-up. The experiments were conducted in two modes of operation during two identical solar days in the month of February 2021 at 11.0168° North, 76.9558° East. They were SAH having baffled absorber without any PCM (SAH-BP), and baffled SAH with OPCM (SAH-BP-OPCM). The baffle plates were attached over the absorber surface in alternative sequential way and OPCM was stored beneath the absorber. The normal commercial grade paraffin was employed as OPCM and the experimentations were carried-out at the constant flow rate of 0.18 kg/s. The results substantiated that the amalgamation of OPCM within the baffled SAH enhanced its performance in terms of energy efficiency. The OPCM improved the energy efficiency of the SAH-BP by 11.25%.

Performance analysis of nanoparticles-enhanced PCM: An experimental approach

In this paper, an experimental analysis of organic PCM is conducted. It includes an experimental study of paraffin type organic phase change material while suggesting a way to improve the low thermal conductivity, a feature that is the main disadvantage of especially organic phase change materials. In particular, temperature profiles of PCM for different hot source temperatures are examined, while determining the heat stored in the material and the speed at which the melting front moves under the assumption of uniform movement of the melt interface and solid material. Subsequently, and in order to increase the conductivity of the PCM and thus the rate of evolution, copper and aluminum oxide nanoparticles powder are added and the hybrid PCM is compared in terms of temperature profiles and storage capacity with the pure PCM. The presence of 0.165% Cu nanoparticles reduces the thermal charge duration by 25.3% while the presence of Cu-Al2O3 hybrid nanoparticles at a concentration of 0.165% −0.816% reduces the duration by 10.8%.

Preparation and thermal properties of encapsulated 1-Decanol for low- temperature heat transfer fluid application

The high heat-carrying capacity of encapsulated phase change material slurries (EPCMS) is instrumental in improving the performance of heat transfer fluid system (HFS). In the present study, we analysed 1-Decanol, a low-cost organic PCM, encapsulated in a urea-formaldehyde shell (UFS) for potential usage in low-temperature heat transfer fluid application (LTHFA). Discrete and uniformly shaped EPCM capsules have been prepared with an encapsulation efficiency of 59.56 % at an optimised core content of 10 g. Further, the thermal response of EPCM was enhanced by preparing EPCM modified (EPCMM) with 2, 6, and 10 wt% GnP or CuO nanoparticles (NP). SEM analysis revealed the rough and smooth surface morphologies of EPCMM with GnP and CuO, respectively. Particles size analysis showed that the prepared capsules are in the submicron size, and FTIR results revealed that 1-Decanol, UFS, and NP are chemically compatible with each other. DSC, FTIR, and TGA results proved that 1-Decanol had been encapsulated inside UFS. Based on the acquired results, EPCMM with 6 wt% GnP and 10 wt% CuO exhibited the most suitable thermal characteristics with an encapsulation efficiency of 56.14 % and 54.52 %, respectively, and thermal conductivity enhancement of 2.19 and 1.98 times that of EPCM, respectively. Experimental results concede that the prepared capsules have suitable thermal and heat transfer characteristics, proving its applicability in LTHFA.

Facile synthesis of microencapsulated 1-dodecanol/melamine-formaldehyde phase change material using in-situ polymerization for thermal energy storage

In this study, a new microencapsulated organic PCM (MicroPCM) was developed and its thermal energy storage (TES) properties were experimentally investigated. The microcapsules were prepared through a facile in-situ polymerization process using 1-dodecanol as the core PCM and the melamine-formaldehyde as the shell material. The microstructural analysis results infer that, the as-prepared microcapsules were spherical in shape, and the existence of carbon, oxygen and nitrogen elements have confirmed the effective formation of the MicroPCM. The average particle size (490.2 nm), surface roughness and with no chemical interaction between the core and the shell materials have paved way for achieving improved storage stability of the MicroPCM. The microcapsules with high thermal storage capability of 91.2 % have exhibited good latent heat of fusion of 79.45 kJ/kg. The microcapsules were thermally stable up to 132.82 °C, which was substantially higher than that of the operating temperature range of the pure PCM. The measured thermal conductivity of the MicroPCM was relatively lower (0.1727 W/m K) which has satisfied the thermal insulation criteria as well. The thermal cycling test conducted for microcapsules showed excellent thermal reliability (reliability index of 94.4 %). Also, no chemical interaction was observed between the core and the shell materials even after 200 heating/cooling process. Based on the test results, it is inferred that, the MicroPCM with enhanced properties can be a promising candidate for low temperature thermal energy storage.

Preparation and thermal properties of shape-stabilized 1, 8-octanediol /SiO2 composites via sol gel methods

A series of 1, 8-octanediol (ODL)/silicon dioxide (SiO2) shape-stabilized composite phase change materials (ss-CPCMs) with different mass fraction of ODL loadings were made via sol–gel method. In ODL/SiO2 ss-CPCMs, ODL acted as the organic PCM and silica gel played the role of supporting matrix to maintain a stable shape of the composites during the phase change. The prepared composite with the 70% mass fraction of ODL still kept the solid form without leakage even if the temperature was much higher than the melting point of ODL. Differential scanning calorimetry (DSC) measurements indicated that the melting temperature of the composites was lower than the pristine ODL and the phase change enthalpy of the composite was close to the theoretical values. Fourier transform infrared (FT-IR) spectroscopy implied that the interaction between the ODL and silica gel was physical adsorption. Moreover, the thermal performance tests indicated that the thermal storage and release rates of the as-prepared ODL/SiO2 ss-CPCMs were enhanced compare to pure ODL. In summary, the composites showed excellent thermal stabilities and reliability, which were suitable for thermal energy storage applications in building envelopes.

Reducing PV module temperature with radiation based PV module incorporating composite phase change material

• Paraffin wax organic PCM was used for numerical simulation. • PV-PCM heat transfer resistivity was investigated using pPCM and cPCM. • Average PV module temperature reduction of cPCM was 6.7 C. • Average PV module efficiency of cPCM increased by 0.46.%. Temperature reduction in a photovoltaic module can improve its efficiency. This paper presents a radiation based photovoltaic module cooled by using composite phase change material that are not in direct contact with the photovoltaic module. A thermal heat transfer network is developed which improves efficiency of the photovoltaic module by using radiation mode to eliminate the issue of phase change material re-conduction, thereby controlling excess thermal energy stagnation in the module. Pure phase change material and composite phase change material are investigated and compared by integrating them 0.6 cm behind the photovoltaic module and performing simulations to determine the optimal thickness of the phase change material matrix. It was found that by using composite phase change material, the thermal resistance between the photovoltaic and the phase change material could be reduced and the photovoltaic module temperature decreased, due to the higher thermal conductivity of the composite phase change material. The simulated efficiency and temperature of the photovoltaic module with composite phase change material installed at the optimum thickness of 2.5 cm were 14.75% and 47.81 C, respectively. The numerical simulation of the new PV-PCM setup was validated experimentally, and simulation results were accurate within an average of 0.4 C.