Use Of Phase Change Materials Research Articles

Investigating the performance improvement of lithium-ion battery cooling process using copper fins and phase change materials (PCMs)

This study investigates utilizing phase change materials (PCMs) along with metallic fins for passive cooling of lithium-ion batteries. PCMs have low thermal conductivity, which is enhanced by incorporating copper or aluminum fins. Numerical simulations using ANSYS FLUENT's Solidification & Melting solver in an axisymmetric configuration are performed. PCM cooling outperforms air cooling, providing up to 15 °C lower maximum battery temperatures as long as PCM remains solid. The findings from the analysis of air cooling versus cooling with PCM demonstrate that the use of phase-change materials enhances battery cooling performance for a specific duration, provided that these materials do not fully liquefy. Adding fins further improves cooling for 0.2 mm thickness, 6 copper fins of 11.67 mm height give optimal performance with 8 °C lower peak temperatures than without fins. Copper fins outperform aluminum due to 60 % higher thermal conductivity but have 3X higher density. For longitudinal fins, 4 fins of 10 mm height perform better than 10 fins of 3 mm height. With high conductivity PCMs like paraffin wax (0.242 W/m.K), varying fin count has minimal impact as heat distributes rapidly. This study establishes guidelines for optimizing PCM-fin geometries and materials to maximize passive lithium-ion battery cooling performance.

Assessment and validation of a numerical model for phase change materials heatsink on thermoelectric devices

The use of phase change materials (PCM) in heatsink designs are gaining attention due to its many favorable properties. Some PCM heatsinks designs have been suggested for use with thermoelectric cooling devices (TECs), however, the heatsink designs are often arbitrary where PCM is just added to voids within the heatsink to improve the thermal properties. There is a need to systematically understand the effects of PCM on TEC performance. While a numerical model is key to such systematic study and optimization, the application involves multiple physical phenomena and the resulting model can be prohibitively expensive to run. In this contribution, a numercical model using computational fluid dynamics (CFD) is built to predict the performance of PCM heatsink for use with TECs as cooling wearable. Experiments are calibrated and carried out to prescribe the boundary conditions and ensure that the multiphysics phenomena are accurately captured. The numerical methodology described here can be used for design optimizations of PCM heatsinks to be used in conjunction with TECs. Our numerical model shows that for maximum TEC efficiency, the PCM should be kept at a liquid fraction of less than 40%.

Thermo-energy performance of a phase change material integrated into lightweight hollow concrete roofs in warm–subhumid climate

The use of phase change materials in building envelopes has attracted the attention of researchers to minimize cooling and heating loads and for thermal comfort regulation. A research gap was found regarding the numerical analysis of lightweight roofs with PCM considering conjugate heat transfer. Thus, this paper aims to evaluate the thermal performance of a lightweight hollow concrete roof with a phase change material (PCM) in a subhumid climate. Three roof configurations with two PCMs were numerically analyzed through computational fluid dynamics. Simulations were conducted using the open-source code OpenFoam and were verified and validated with good agreements proving the confidence of the proposed methodology for building envelope design purposes. The roof configurations with fully-filled PCM exhibited the best thermal behavior, reaching higher temperature reductions between 1.4 °C to 2.0 °C, respectively, and reductions of indoor peak heat flux by approximately 47 % compared with the reference case. The roof fully-filled with an inorganic PCM with a melting temperature of 25 °C was the most energy-efficient roof configuration because it achieved the highest energy savings of 65.5 %, lowest electricity costs of 0.85–4.33 USD m−2, and lowest CO2 emissions of approximately 18.31 kgCO2e m−2. The results demonstrated that the utilization of PCM into lightweight concrete roofs in subhumid climates is very promising.

Research Progress of Photovoltaic Cooling Systems Based on Phase Change Materials: An Overview

Photovoltaic technology plays a crucial role in harnessing renewable energy. While photovoltaic panels directly convert solar energy into electricity, more than 50% of solar radiation is lost as waste heat, diminishing the overall efficiency of the panels. This study reviews various cooling technologies for photovoltaic systems, focusing on the use of phase change materials for cooling in photovoltaic systems. Phase change materials, known for their high latent heat capacity, are extensively used in thermal energy storage applications. Incorporating phase change materials in photovoltaic systems can increase thermal storage potential by 30–50% compared to conventional systems, leading to a 70% extension in heat storage duration and various levels of enhanced power output. The main purpose of the article is to review the advantages and disadvantages of various technologies, determine the research direction of phase change materials for cooling systems in photovoltaics, and ensure the reliability of this technology.

Analysis of NePCM melting flow inside a trapezoidal enclosure with hot cylinders: Effects of hot cylinders configuration and slope angle

Hot cylinders within the cavity can find diverse thermal applications, ranging from electronic devices and heat exchangers to solar systems, nuclear reactors, and the thermal design of passive cooling systems. Consequently, considering the use of phase change materials (PCM) close to hot cylinders emerges as a viable method for both cooling and storing thermal energy. In this work, two hot cylinders are arranged vertically and horizontally in the nano-enhanced phase change material (NePCM) trapezoidal enclosure with varying angles. The novelty of the current study lies in the fact that no prior research has explored the impact of hot cylinders arrangement on the melting process of a NePCM within a trapezoidal cavity, considering various inclination angles. The fixed grid, adaptive mesh refinement, and enthalpy-porosity method are used to model the melting flow. The numerical results indicate that the trapezoidal enclosure with vertically arranged hot cylinders exhibits better thermal performance than the other configuration. It is also found that the full melting time for both arrangements is minimum when the angle of the trapezoidal enclosure is γ=+40°. The reduction in full melting times for the vertical and horizontal arrangements of this angle are 25.3% and 29.6%, respectively, compared to the trapezoidal enclosure with γ=0.0°. Moreover, the NePCM with the graphite nanoplatelets (GNPs) of φ=1.0% has the shortest melting time for 0.0%≤φ≤3.0%. As future research, further exploration into the complexities of non-Newtonian NePCM flow can be pursued. Additionally, there is potential to explore modifying the cylinders' geometry into elliptical forms, encompassing a range of aspect ratios.

A review of integrated battery thermal management systems for lithium-ion batteries of electric vehicles

Lithium-ion batteries have emerged as a promising choice for electric vehicle applications. However, thermal runaway and related catastrophic issues perplex the research community when batteries are subjected to varying charging/discharging and different ambient temperatures. In order to keep the batteries under a safe zone of temperature, battery thermal management occupies utmost importance and hence researchers are switching over to a combination of either two or three strategies since single stragaty could not meet effective thermal management. In a combined strategy, the use of phase change materials and is highly essential due to their inherent thermo-physical properties; both organic and inorganic types have been explored. To enhance the heat dissipation, the phase change materials, regarded as composite phase materials, are being added with graphite powder, nanomaterials, metal foams, and fins are being arranged to the battery cells. The present review enumerates the recent progress made in achieving good thermal performance with hybrid/integrated battery thermal systems with an emphasis on the use of composite phase change materials. The review revealed that the hybrid strategy is performing well, machine learning and advanced optimization methods are being applied to understand the state of health of batteries. Few works are focussed on the mitigation of thermal runaway propagation serving the composite phase change materials as effective flame retardants. The current status and challenges being faced in the use of LIBs is also briefed. It is essential to develop economical integrated battery thermal management systems with parasitic power losses that are compact and safe to attract many city dwellers to adopt pure electric vehicles besides meeting the mandate of sustainable development goals. The review is an attempt to provide a ready reckoner in the area of integrated battery thermal management involving composite phase materials.

Experimental Investigation of the Effect of Phase Change Material in Mitigation of Heat

The use of a latent heat storage system using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. PCMs have been widely used in latent heat thermal storage systems for heat pumps, solar engineering, and spacecraft thermal control applications. The uses of PCMs for heating and cooling applications for buildings have been investigated within the past decade. There are large numbers of PCMs that melt and solidify at a wide range of temperatures, making them attractive in a number of applications. This paper also summarizes the investigation and analysis of the available thermal energy storage systems incorporating PCMs for use in different applications.

3D Nanostructuring of Phase-Change Materials Using Focused Ion Beam toward Versatile Optoelectronics Applications.

In recentyears, phase-change materials have gained importance in nanophotonics and optoelectronics. Sizable optical contrast and added degree of freedom from phase switching drive the use of phase-change materials in various optical devices with outstanding results and potential for real-world applications. The local crystallization/amorphization of phase-change materials and the corresponding reflectance tuning by the crystallized/amorphized region size have potential applications, for example, for future dynamic display devices. Although the resolution is much higher than in current display devices, the pixel sizes in those devices are limited by the locally switchable structure size. Here, the spot sizes are further reduced by using ion beams instead of laser beams, dramatically increasing pixel density, demonstrating superior resolution. In addition, the power to sputter away materials can be utilized in creating nanostructures with relative height differences and local contrast. The experiment focuses on one archetypal phase-change material, Sb2 Se3 , prepared by pulsed-laser deposition on a reflective gold substrate. This study demonstrates that structural colors can be produced and reflectance tuning can be achieved by focused ion beam milling/sputtering of phase-change materials at the nanoscale. Furthermore, the local structuring of phase-change materials by focused ion beam can produce high-pixel-density display devices with superior resolutions.

A Numerical Study to Improve the Efficiency of Solar Collector used for water heating using Phase Change Material

Solar water heaters are an effective technology for harnessing renewable solar energy to provide hot water for households and businesses. However, their efficiency can be impacted by factors like intermittent sunshine, heat losses, and low radiation intensity. The aim of this study is to increase the efficiency of solar water heaters through the use of phase change materials (PCMs). PCMs have the ability to store latent heat during phase change, releasing it later when needed. This study uses numerical simulations to analyze the effect of integrating different PCMs into a flat plate solar collector design. The findings could then be validated experimentally and applied to improve the real-world performance of solar water heating systems. The PCMs are placed inside the collector to absorb heat during the day and release it after sunset to continue heating the water. The research seeks to determine the optimal PCM properties, structure, and placement within the collector to maximize heat storage and transfer. The efficiency and performance of the solar collector system with different PCM configurations have been compared to those of a conventional collector without PCM. The outcomes uncover that the use of suitable PCMs can significantly improve the efficiency and heat output of the solar collector, especially during periods of low radiation and after sunset. The optimal PCM configuration maintains higher water temperatures for longer, allowing solar water heating to continue into the evening. The results may provide valuable insights for using PCMs to boost the efficiency of solar thermal technologies

An Economic Analysis of Energy Saving and Carbon Mitigation by the Use of Phase Change Materials for Cool Energy Storage for an Air Conditioning System—A Case Study

Phase change materials are increasingly used because they can be used for cold energy storage in air conditioning systems to increase system efficiency and achieve energy savings. However, many potential adopters of phase change cold storage systems fail to consider environmental and economic factors, so feasibility assessments are difficult and significant gaps between expected benefits and actual outcomes become apparent. This study establishes an economic analysis model using a technology company in Taiwan as an example. The model determines the costs and energy-saving carbon reduction benefits of implementing phase change materials to allow businesses to achieve energy-saving, carbon reduction, and sustainable development objectives. The results of this study demonstrate that companies can achieve a 32% reduction in electricity costs, reduce energy consumption by 118,411 kWh per year, and reduce carbon emissions by 60,272 tons per year by adopting phase change materials. The dynamic payback period is as little as 2.9 years for low-load conditions. A cost–benefit analysis also shows that the use of phase change materials for energy storage, coupled with the prior construction of energy storage areas, provides the maximum economic benefits and is the optimal choice.

Critical review on thermal performance enhancement techniques for flat plate solar collectors

Supply of energy against continuous increase in energy demand is a great challenge for the present time. This has compelled the researchers to develop energy-efficient and performance-enhanced devices. Solar energy, being the capable source to supply the clean energy can be harvested with the help of flat plate solar collectors (FPSCs). In order to enhance the thermal performance of FPSC researchers have considered various aspects, for example, design modification, heat transfer fluid having enhanced thermophysical properties, use of nanofluids, reduction in heat loss, use of enhancement devices, use of phase change materials and porous materials. The present article describes in detail these methods and compares the results obtained by the respective researches. Experimental as well as numerical works have also been presented. A comprehensive review for the thermal performance enhancement techniques used in FPSC has been presented. The objective of this review is to provide a valuable framework for evaluating and comparing different techniques for enhancing FPSC performance. The review aims to help identify the most appropriate approach and gaps in current research and proposes potential areas for future enhancements, which is expected to assist researchers.

Research on modified expanded graphite/eutectic salt composite phase change material in cold chain transportation

Attention to the use of phase change materials (PCMs) in cold chain transportation has increased in recent years. In this work, a form-stable composite phase change material (CPCM) prepared by a novel eutectic salt (Na2SO4·10H2O-MgSO4·7H2OH2O) PCM composite with modified expanded graphite (MEG) was investigated. The hydrophilicity of expanded graphite (EG) and its compatibility with the eutectic salts were improved by coating SiO2. The results showed that microstructure of the EG was maintained after modification, and adsorption of the PCM by the MEG was 55.23 wt% higher than that of the EG. The CPCM with 20 wt% MEG exhibit a high enthalpy of 180.8 J/g, the phase transition temperature of −5.6 °C and a high thermal conductivity of 5.183 W/(m·K). The thermal conductivity of CPCM was 8 times as large as that of the PCM. Moreover, the thermal performance of the CPCM was small change after 200 thermal cycling, exhibiting good thermal cyclic reliability. Besides, a potential application test of the form-stable CPCM was performed through a low temperature insulation box. It showed that form-stable CPCM can control sudden temperature fluctuation and maintain stable temperature for longer time inside the insulation box.

Enhancement of perovskite spontaneous emission by phase change materials

Controlling the spontaneous emission intensity of perovskites is one of the main unsolved problems of perovskite photonics. To date, to solve this problem, chemical methods have been used to passivate defects in the material and thereby to increase the radiation intensity. However, this method does not allow reversible control of the spontaneous emission intensity of perovskites. Here, we theoretically demonstrate the reversibly controlling the spontaneous emission of perovskites through the use of phase change materials (PCMs). We show changes in the Purcell factor by more than 50% with a change in the PCM phase in the all-visible wavelength range. We also conduct a comparative analysis of the two most popular PCMs, namely Ge–Sb–Te and SbSe. We anticipate that our theoretical results will serve as a foundation for future technological solutions for the development of tunable radiation sources.

The Use of Phase Change Materials to Improve the External Walls' Thermal Parameters of Heated Buildings

Currently, it is estimated that the construction sector consumes over 40% of the energy produced and about 50% of the mass of processed materials. As a consequence, there is a challenge to look for alternative material solutions allowing for the storage and conversion of energy. Phase change materials give us such opportunities. Their introduction leads to additional benefits related to thermal parameters. The work presents a short overview of PCMs along with the possibility of their application. Then, as part of the research, the selected phase change material was applied to the internal plaster layer of an external wall to check its activity. The obtained results were compared to the values of reference samples (without PCM). The proposed solution leads to the improvement of the analyzed partitions' thermal parameters.

Passive and Active Techniques for Cooling Photovoltaic Cell using PCM: An Investigation of Recent Advances

Photovoltaic (PV) technology is one of many renewable energy sources, which converts solar energy directly received into electricity. In recent years, PV has advanced quickly as researchers try to make it more effective. 80% of the solar radiation that hits PV cells is absorbed, but only 12–18% of that energy is converted into electricity, with a maximum conversion rate of 24%. This indicates that a significant amount of sunlight is lost irretrievably. when a significant portion of the solar energy that is absorbed but not used by the photovoltaic process is converted to heat, which causes PV cells' operating temperature to increase above their design temperature, Consequently, the cell's effectiveness declines as a result of this increase. The crystalline silicon-based PV cells’ efficiency drops by 0.5% for each Celsius increase in temperature of operating. When operating temperature of cell exceeds design temperature, open-circuit voltage decreases significantly while the closed-circuit current slightly increases. Research has shown that PCMs can be applied in a variety of ways to enhance performance of PV cells, including as a coating applied directly onto the surface of the modules, as a heat exchanger in contact with module's back, or as an integrated component within the module itself. One recent advancement in the area of PCM-based cooling of PV modules is the development of hybrid cooling systems that combine PCMs with other cooling methods, such as air or water cooling. These hybrid systems have been shown to significantly improve the temperature stability and efficiency of PV modules compared to single PCM-based systems. PCMs have unique thermal properties that make them suitable for use in cooling systems because they can store and release thermal energy when phase transitions occur due to their high latent heat capacities. Recommendations for the use of phase change materials in Photovoltaic cooling, continue to research and develop new phase change material-based cooling systems that are more stable, have higher thermal conductivity and are effective in a wider range of temperatures.

Recent advances in phase change materials for thermal energy storage.

Efficient storage of thermal energy can be greatly enhanced by the use of phase change materials (PCMs). The selection or development of a useful PCM requires careful consideration of many physical and chemical properties. In this review of our recent studies of PCMs, we show that linking the molecular structures of organic molecules to their physical properties can be used to focus attention on the most useful PCMs, including eutectic mixtures. Two of the major limitations concerning broader use of phase change materials are low thermal conductivity, especially for organic phase change materials, and suitable containment. We have addressed both issues in our recent investigations of novel form-stable composite PCMs with a freeze-cast matrix. The use of thorough experimental investigations, including cycling of materials hundreds or thousands of times through the melt-freeze processes, promotes our goals of advancing the use of PCMs for increased energy efficiency and sustainability.

Experimental Investigation of the Performance of a Household Refrigerator Using Phase Change Material

A household refrigerator represents an essential device for all houses nowadays. The electric energy consumed by the refrigerator and the fluctuation of the temperature inside the fresh food cabin is the main two problems affecting its performance. Incorporating phase change material (PCM) inside the refrigerator is one of the solutions for the previous mentioned problems. In the present study, a water PCM is added to the cabinet of 220-litters double door refrigerator. The PCM (0.5 ml of water) is added at three different locations, touch the front of the evaporator part inside the cabin, touch the rear of the evaporator part in the cabin, and far away from the evaporator part inside the cabin. The location of the PCM determines how much energy is released and stored from the evaporator. The use of phase change material (PCM) touch to the evaporator increases the rate of heat transfer due to the conduction method being used throughout the whole heat transfer process from the evaporator to the phase changematerial (PCM), which raises the refrigeration system's COP (coefficient of performance). The experimental test period is 24 hours for each day. Firstly, the refrigerator is tested without using PCM, and the power consumption, the temperatures at different points for the refrigerator, suction pressure, discharge pressure, the ambient temperature, and the time on period and time off period of the compressor are measured. Secondly, for same testing period all previous parameters are measured with using PCMat different locations inside the refrigerator. The results show that, adding the PCM (water) behind the evaporator led to increase the COP by 21.97%, increase the compressor off time by 73 minutes, reduction in power consumption of 14.4%, decrease of exergy losses of the system by 8% and temperature fluctuation reduced inside the fresh food cabin, that enhance the quality of stored food. Adding the PCM front the evaporator improve the previous parameters but less than that of the first case. The third location, adding the PCM far away from the evaporator has no improvement on the refrigerator's performance.

Unlocking the potential of passive cooling: A comprehensive experimental study of PV/PCM/TEC hybrid system for enhanced photovoltaic performance

In recent times, one major direction in which researchers are taking interest is the cooling of PV systems, and in that direction, passive cooling techniques like thermoelectric cooling, the use of phase change material, or hybrid PV systems based on TEC and PCM are at the forefront of this research interest as the first-generation solar PV has a very low conversion efficiency that is primarily caused by the high temperature of the cells. This research conducts a thorough long-term experimental study on PV/PCM/TEC, exploring their effectiveness under changing weather conditions. A new design integrates PCM and TEC on the PV module's backside, ensuring free convection is maintained. The study aims to assess the potential of these cooling techniques for enhancing photovoltaic system performance. On average, the phase change temperature of the ternary mixture gradually increases from 27.97 °C to 41.59 °C, providing a complete pattern of effectiveness and ineffectiveness of phase change material. The highest average value for maximum temperature reduction of 9.28 °C and maximum output power of 9.69 % was achieved by PV/PCM/TEC in comparison to reference PV module. Another notable finding is that TECs based on PCM offer higher power output compared to TECs without PCM, while in the absence of PCM, TECs and the PV interface require a conductive thermal paste to enhance heat transfer and improve power output. Despite the limitations posed by the fixed encapsulation thickness and quantity of the phase change material, the reported results demonstrate the positive impact of PCM in comparison to both standard PV and PV/TEC systems.

Characterization of 1-tetradecanol’s performance as a phase change material in thermally modified ash wood

The use of phase change materials in thermally modified wood presents an innovative way to enhance the thermal properties of wood, contributing to energy efficiency and thermal comfort in various applications. However, careful consideration of the materials and methods used is essential to ensure the effectiveness and practicality of this technology. Phase change materials (PCM) can be integrated into thermally modified wood through various methods. One common method is impregnation, where the PCM is infused into the wood structure. Another method could be the application of PCM in coatings or finishes applied to the wood surface. In this study, 1-tetradecanol (TD) was used as a PCM and its effectiveness on thermally modified ash wood (TMA) was investigated. TMA has better thermal insulation properties, which are essential in energy storage applications to minimize heat loss. For this purpose, the leaching of TD from TMA was examined. Differential scanning calorimetry (DSC), thermogravimetric analyses (TGA), fourier transform infrared spectroscopy (FTIR) were examined. According to the results, there was a small amount of leakage in the leakage test. TGA analysis showed that TD/TMA left a lower residue of 16.30% at 800°C compared to the residue of 18.20% left by untreated thermally modified wood (TMA).

Evaluation of Phase Change Materials for Pre-Cooling of Supply Air into Air Conditioning Systems in Extremely Hot Climates

This research investigates the use of phase change materials (PCMs) in thermal energy storage (TES) unit-based cooling systems to increase the efficiency of air conditioners (ACs) by reducing the air inlet temperature. This study aims to evaluate different configurations of PCM enclosures, and different PCMs (paraffin and salt hydrate), by changing the speed of inlet air to achieve heat reduction of inlet air. The study includes experimental and simulation investigations. Every configuration simulates the hot-season atmospheric conditions of the UAE. A duct containing enclosures of paraffin RT-31 and salt hydrate (calcium chloride hexahydrate) was used for the simulation study using ANSYS/Fluent. A conjugate heat transfer model employing an enthalpy-based formulation is developed to predict the optimized PCM number of series and optimum airflow rate. Four designs of the AC duct were modelled and evaluated that contained one to four series of PCM containers subjected to different levels of supplied air velocities ranging from 1 m/s–4 m/s. The simulation study revealed that employing four series (Design 4) of PCM enclosures at a low air velocity of 1 m/s enhanced the pre-cooling performance and reduced the outlet air temperature to 33 °C, yielding a temperature drop up to 13 °C. The performance of salt hydrate (calcium chloride hexahydrate) was observed to be better than paraffin (RT-31) in terms of the cooling effect. Characterization of paraffin wax (RT-31) and salt hydrate was performed to establish the thermophysical properties. The experimental setup based on a duct with integrated PCM enclosures was studied. The experiment was repeated for three days as the repeatability test incorporating RT-31 as the PCM and a 3 °C maximum temperature drop was observed. The drop in the outlet air temperature of the duct system quantifies the cooling effect. Net heat reduction was around 16%.