Usage Of Phase Change Materials Research Articles

Energy- efficient cementitious mortar containing clay based shape-stable phase change material: Development, characterization and temperature controlling performance

The need for buildings to ensure a comfortable thermal environment is increasing, leading to a surge in energy consumption. This study proposes an innovative approach to tackle thermal energy storage challenges in buildings by formulating a unique cementitious mortar containing a shape-stable composite of Saudi Arabian natural clay and methyl stearate phase change material (PCM). The inclusion of natural clay, chosen for its cost-effectiveness and eco-friendliness, addresses the issue of methyl stearate leakage—a common concern with PCM usage. Despite PCM incorporation, the mixture maintains desirable fluidity and consistency, albeit with a slightly reduced dry unit weight and compressive strength. Differential scanning calorimetry analysis defines key characteristics of the resulting shape-stable NC/MS composite PCM, including a melting point of 33.81°C and a latent heat storage capacity of 56.15 J/g. Empirical testing demonstrates the efficacy of the natural clay/PCM composite in temperature moderation. During periods of elevated external temperatures, the NC/PCM specimen effectively lowers room-center temperatures by up to 4°C and sustains a cooler environment compared to the control room for almost 8 hours. Additionally, the composite PCM limits the maximum increase in room center temperature post-sunset to only 2.49°C, showcasing its capability in stabilizing indoor temperatures. This innovative PCM composite responds dynamically to ambient temperature variations, transitioning between solid and liquid states to release stored latent heat, consequently reducing building heating and cooling loads, enhancing energy efficiency. The natural clay/PCM composite presents a promising solution for advancing building thermal energy storage systems, aligning with energy efficiency and sustainable design objectives.

Phase change materials in textiles: synthesis, properties, types and applications – a critical review

Phase change properties of clothing gain attention of the researcher now for their significant unique ability to absorb, release, store, and deposit temperature during phase transition. Phase change materials have been widely used and utilized now in various fields, as well as in textiles. In apparel products, phase change materials are used to introduce various special features, especially its make garments smart or have technical functions. Various researchers pay attention to this area for its large organic and inorganic resources. This review paper summarizes the road map of phase change materials in textiles, including the way of synthesis, the characteristics of phase change materials, and their applications in smart textiles. In addition, the diverse usage of phase change materials in different textiles is discussed. It also tries to cover the principles of phase change behavior, phase change material types, and their thermal properties. After that, the paper will try to mention the potential benefits and challenges associated with utilizing phase change materials in various applications that have been discussed here. Finally, this paper concludes with the mass acceptance of phase change materials in various technological advancements, along with a short note about future research opportunities.

An Overview of Phase Change Materials and Their Applications in Pavement

The composite of a phase change material (PCM) and bitumen or asphalt as a matrix is expected as a new, advanced material for road construction. The main motivation for this article was to show the new possibilities and perspectives of developing the pavement with the usage of PCMs. Incorporating PCMs into paving materials can improve their properties, including allowing the regulation of the pavement temperature, enhancement of the pavement durability, and avoiding the phenomenon of a heat-island on the road. The main purpose of this article was to evaluate contemporary investigations in the area of the application of PCMs in pavement materials, especially asphalt and bitumen; to summarize the advantages and disadvantages of the implementation of PCM for road construction; and to discuss further trends in this area. This manuscript explored the state of the art in this area based on research in the literature. It shows the possible material solutions, presenting their composition and discussing their key properties and the manufacturing technologies used. The possibilities for further implementations are considered, especially economic issues.

Synthesis, characterization and application of a magnetic nanoencapsulated PCM in enhancing the natural convection in a cube cavity

Encapsulation of phase change materials (PCMs) is an intelligently effective way to overcome the challenges of PCMs usage in heat storage and transfer applications. At the first stage of the current study, a novel magnetic nanoencapsulated PCM (M−NEnPCM) consisting of n-Octadecane (n-C18) coated with a poly methyl methacrylate (PMMA) shell was synthesized through the miniemulsion ultrasonic-assistant polymerization technique. The magnetic property was introduced to the nanocapsules by adding surface-modified Fe3O4 nanoparticles into the core during the formation step. The dynamic light scattering (DLS) results showed an average nanocapsule size of 78 nm. The scanning electron microscope (SEM) along with transmission electron microscope (TEM) images confirmed the spherical shape with a core/shell structure of the M−NEnPCM. According to the differential scanning calorimetry (DSC), M−NEnPCM had melting and crystallization latent heats of 116.47 and 124.71 J/g, respectively. Moreover, based on vibrating sample magnetometry (VSM) results, the superparamagnetic property of M−NEnPCM is proved. At the second stage, the performance of water suspensions containing different amounts of the as-prepared nanocapsules in enhancing the natural convection in a cube cavity was investigated under various heat fluxes and magnetic field flux densities. The results illustrated that the use of nanocapsules leads to enhance the natural convection up to 2 times higher than that of pure water; while there are optimum levels of M−NEnPCM concentration and magnetic field flux density at which the heat transfer coefficient is maximized.

Coupled effects of corrugation and rotation on the phase transition and thermal process in a vented cavity under MHD convection

One of the challenges in the utilization of phase change materials (PCMs) is their low thermal conductivity. Therefore, for effective usage of PCMs in thermal systems, novel methods for phase change process control such as geometry modification and incorporating different boundary conditions can be adopted. In this study, phase transition and thermal process in a triangular shaped wavy enclosure equipped with spherical shaped encapsulated PCM are explored under magneto-convection of nanofluid. The inner walls of region where PCM is embedded is rotating and sinusoidal form of corrugation is considered for the wavy wall of the triangular cavity. Numerical calculations are done for different values of Re (200≤Re≤1000), Rew (−2500≤Rew≤2500), Ha (0≤Ha≤60), wave amplitude (0≤Ap≤0.1H) and wave frequency (2≤Np≤8). It is observed that when rotations are active at Rew=100, phase transition time (TF) is reduced by 12.5% while it is increased by 16.6% at Rew=0. Magnetic field is effective when used without rotation of the inner part. The amount of reduction of TF with magnetic field at the highest strength is obtained as 15.8%. The heat transfer is reduced with higher Ha for stationary and rotating cases while reduction amount up to 14% can be achieved. Amplitude of the wavy form of cavity wall is influential on the phase change process at Rew=0 and TF is reduced by about 14.5%. The contribution of amplitude and frequency of the wave form on the heat transfer is very slight. Optimum parameter set for lowest TF is obtained at (Re, Rew, Ha, Ap, Np) = (600, 2500, 60, 0.075H, 2) while for highest heat transfer rate it becomes (Re, Rew, Ha, Ap, Np) = (1000, 2500, 0, 0.1H, 8). Generalized neural network based modeling is found to be an efficient way of predicting the time dependent behavior of phase change process with respect to changes in operating parameters such as Re, Rew and Ha.

Thermal energy storage via waste heat from finned heater by using different phase change materials in a closed space

In this study, a numerical analysis of the melting of phase change materials (PCMs), is analyzed in a closed space, which is heated from the bottom wall. The heater has a set of fins with constant geometry, placed on the bottom heated wall. The closed space has also two rectangular-shaped containers (placed horizontally), which are attached to the vertical walls at different dimensions and locations. Each of the containers has different types of PCMs, which receive waste heat from the fins. The performance analysis of the combined system is carried out by solving governing equations using the finite volume technique was used to solve the transport equations. The thermal performance of the composite system is assessed for the wide range of geometrical parameters such as length ratios of the fins (Lp), height ratios (c/H), and flow control parameters such as Grashof numbers (Gr). The result showed that the inclusion of PCM containers can effectively utilize the waste heat and can modulate the thermal transport process significantly. The position and size of the fins significantly alter the convective process inside the enclosure. The flow structure shows asymmetric features due to the obstruction by the fins attached to the vertical walls. Too much closure position of the PCM-filled longer fins to the fins assembly leads to the multi-cellular vortices like ‘Bénard cell’ due to the strong temperature gradient between the two sets of fins. For the long fins, too much closure position reduces the total melting time. The usage of PCM 2 is always beneficial for faster acclimation energy due to fast melting for any length and position of the fins. Different phase change materials and their melting behaviors are studied first time in this work to get cooling effect of a finned heating system, which is the main originality and the work. Such a concept could be adopted as thermal energy storage (TES) system, which can benefit the reduction in energy losses.

Discrete thermokinetic computational model of laser-induced phase transitions in phase-changing materials

This paper presents a thermokinetic computational model of phase transitions in GST225 (germanium–antimony–tellurium) thin films [as well as other phase change materials (PCMs)] induced and initiated by the impact of nano- and femtosecond laser pulses in a wide energy fluence range according to the results of experimental studies using Raman spectra and thin-film samples of TEM cross-sectional image analysis. Applying this phase transition model makes it possible to understand the mechanism of the induced phase transition regarding the usage of PCMs in photonics and optoelectronic devices, which require precise control of the phase state of their PCM-based active elements for their functioning. The proposed model shows the internal structure of the sample, generating both the profile of the crystalline fraction distribution over the sample's depth, providing images of virtual TEM sections, as well as the volume distribution of the crystalline phase.

Performance enhancement of building energy through the combination of dynamic insulation panels and phase changing materials

The use of phase change materials (PCM), a type of heat transfer thermal storage substance, shows the opportunity to enhance the thermal inertia of these structures lacking significantly altering present construction methods. Because of the decreased indoor temperature swings and the load reduction, the usage of PCMs in buildings has the potential to deliver higher indoor temperatures for inhabitants as well as weaker export power consumption. Thermal energy storage (TES) systems based on phase change material (PCM) is identified as among the most enhanced energy techniques to improve eco-efficiency and conservation. The proposed dynamic insulating material and system (DIMS) allows for thermal resistance to be adjusted based on interior and outside variables. While it can be shown that using PCM and DIMS in facades enhances energy efficiency, there have been no previous studies that looked at the combined effect of the two technologies. Explore a unique wall design that includes a sheet of PCM made up of two levels of DIMS in this research. In most of the seasons and building orientations studied in this research, the PCM-DIMS-integrated wall saves much more energy than the DIMS-only combined barrier or the PCM-only combined walls. The PCM-DIMS-integrated walls can give a 15% to 72% decrease in yearly radiant heat then a 7% to 38% reduction in annual heat loss, based on the environment. The findings of this study highlight the necessity for scaled dynamic insulating layers for structures, as well as thermal storage devices.

Energy, economic and environmental impact analysis of phase change materials for cold chain transportation in Malaysia

The tropical climate of Malaysia presents higher environmental temperatures ranging from 27 to 31 °C and refrigerated semi-trailer trucks are utilized in cold chain transportation which is subjected to high thermal stresses and leads to elevated refrigeration load requirements. This subsequently causes a surge in diesel fuel consumption by the auxiliary refrigeration unit and greenhouse gas emissions into the atmosphere. To address the issue, this research evaluates the integration of phase change material (PCM) in refrigerated vehicle walls for latent heat storage purposes, which consequently reduces refrigeration load. Reference cases without PCM and 10 different PCM cases of commercially available organic-based paraffin PCM are investigated, whereby the conventional insulation method of a refrigerated semi-trailer is modified by adding a layer of PCM within its envelope, to simulate refrigeration loads during an 8-hour vehicle operational period. The PCMs are assessed based on their physicochemical properties, and performance in energy savings, economic, and environmental benefits. Results show that daily refrigeration loads can be reduced up to 34.4 % upon PCM integration in refrigerated vehicle walls, and besides, economically, the solution is highly profitable with a benefit-cost ratio above 1. The highest performing PCMs in terms of energy savings yield short payback periods of <3 years, which are at least 2.6 times lesser than the vehicle's lifetime, whilst providing greenhouse gas emission savings of above 2700 kgCO2/year. This research indeed serves as a starting point to explore the large-scale usage of PCMs in cold chain transportation in Malaysia.

Energy performance enhancement of residential buildings in Pakistan by integrating phase change materials in building envelopes

The residential sector of Pakistan is a prime consumer of energy. With the fossil fuel-dependent energy generation setup and an increasing energy supply–demand gap, Pakistan is headed towards an energy fiasco. Therefore, drastic measures are required to enhance the energy efficiency of residential buildings in Pakistan. The current study is aimed to numerically investigate the energy performance enhancement of residential buildings by integrating Phase Change Materials (PCM) in the building envelopes of five major cities of Pakistan having different climates. The numerical computations are carried out in open-source building-simulation software, EnergyPlus. Initially, fifteen suitable PCMs are evaluated for a single-room base case house. CrodaTherm24 having a melting temperature of 24 °C with a thickness of 40 mm is found to be the optimum PCM choice when it is placed on the inner sides of building envelopes. It is then integrated into typical single-Storey and two-Storey multi-zone residential buildings. For a single-Storey building, the average monthly energy saving of 44.9% is achieved in Islamabad, 35% in Karachi, 32% in Lahore, 35% in Peshawar, and 49.6% in Quetta while for two-Storey buildings the average monthly energy saving of 12%, 21.4%, 15.5%, 12.9%, and 13.5% are achieved, respectively. The economic feasibility of implementing PCM in building envelopes is evaluated through static and dynamic payback period calculations. The usage of PCM for energy efficiency enhancements of residential buildings is found to be economically feasible for Lahore, Karachi, and Peshawar whereas, it is unsuitable for Islamabad and Quetta.

Incorporating phase change materials into glazing units for building applications: Current progress and challenges

• Both light and heat transfer characteristics of glazing systems should be considered. • Usage of phase change materials helps reducing energy loss through glazing systems. • Measurement and numerical models are inadequate to study photo-thermal transmission. • More research on effect of phase change materials on acoustic performance is needed. • Database lacks optical properties of solid and molten nano-phase change materials. Building envelopes consist of transparent and non-transparent components, and pose distinct opportunities and challenges in energy conservation. Glazing envelopes, which are transparent, are mainly responsible for the lighting and ventilation of buildings, but the acoustic performance may be weakened. Since glazing envelopes suffer from the defects of high solar transmittance, poor thermal insulation, and low thermal inertia, their energy-saving technologies are significantly different from those of non-transparent envelopes. Different energy-saving technologies have been studied to improve the optical and thermal performance of glazing envelopes. However, there is a lack of a review study involving the phase transition process and the improvement of photo-thermal transmission in glazing envelopes containing phase change materials. The present work provides a comprehensive overview of research advances in optical transmittance, thermal resistance, and thermal inertia along with photo-thermal transmittance in glazing envelopes, with a special focus on the integration of phase change materials. The study reveals that measurement and numerical models are inadequate to study photo-thermal transmission. Besides, it is identified that there is a research gap in the acoustic performance of glazing systems incorporating phase change materials, and there is a lack of database on the optical properties of phase change materials containing nanoparticles.

Improving the thermo-economic performance of hemispherical solar distiller using copper oxide nanofluids and phase change materials: Experimental and theoretical investigation

In the present work, a thermo-economic performance of the modified hemispherical solar still (MHSS) was studied and compared to traditional hemispherical solar still (THSS). The modulations accounted for two additives, namely: paraffin wax as phase change materials (PCM), and copper oxide (CuO) nanoparticles. Three cases of MHSS were investigated and compared to THSS: (0.3 wt%) CuO nanomaterials were immersed in the basin water, implementing PCM container below the basin, and combining PCM container below the basin plus mixing CuO nanoparticles in the basin water. The basin water depth in all stills was set at 1.0 cm in all cases. Moreover, the thermo-economic performance of the four studied cases was compared and evaluated by determining the freshwater productivity, the daily energy efficiency, and the freshwater cost. Experiments have been carried out on the proposed hemispherical distillers under hot climatic conditions of El-Oued (33°27′N, 7°11′E), Algeria. The results show that the single utilization of CuO/water nanofluid and pure PCM improved productivity by 60.41% and 29.17%, respectively, compared to THSS. While, the dual usage of PCM and CuO/water nanofluid further enhanced the productivity by up to 80.20%, relative to THSS. Moreover, the daily energy efficiencies of the hemispherical distillers under the different studied cases (THSS, MHSS/PCM, MHSS/CuO-water nanofluid, and MHSS/PCM + CuO-water nanofluid) were found to be 35.52%, 45.45%, 56.46%, and 63.61%), respectively. The economic feasibility of these modifications presented that the dual usage of PCM and CuO/water nanofluid is more effective as it reduces the cost of freshwater production by 75% compared to THSS. In the third distiller (Modified hemispherical solar still with 0.3 wt% CuO/water nanofluid (MHSS-CuO/water NF)), the modified was done by adding (0.3 wt%) copper oxide (CuO) nanomaterials to the basin water, to improve the thermal properties of nanofluid and increase the intensity of the absorbed solar energy. In the fourth distiller (Modified hemispherical solar still with paraffin wax as phase change materials and 0.3 wt% CuO/water nanofluid (MHSS-PCM + CuO/water NF)), it was designed and constructed a circular galvanized steel container 1 mm thick, 340 mm diameter, and edge height 40 mm, coated with the black pained. This container was placed inside the wooden basin of the hemispherical solar still. A gap of 20 mm thickness was maintained between the container and the wooden basin on the bottom side and sidewall. 2.0 kg of paraffin wax as phase change materials was placed in the gap between the container and the wooden basin, to store the solar energy in the periods of higher solar rays and recovery it in the periods of low solar rays and after sunset. Moreover, in this modification copper oxide (CuO) nanomaterials were also added to the basin seawater with a concentration of 0.3 wt%, to improve the thermal properties of saline water and increase the intensity of absorbed solar energy, and improve the rates of heat transfer. • Dual usage of PCM and CuO nanofluid has great influence on hemispherical distiller performance. • Thermo-economic performance of the modified hemispherical solar still was studied. • Dual usage of PCM and CuO/water nanofluid enhanced the productivity by 80.20%. • Dual usage of PCM and CuO/water nanofluid reduces the freshwater cost by 90%. • Daily efficiency of MHSS with dual usage of PCM and CuO/water nanofluid reached 63.61%.

Influence of the number of holes and two types of PCM in brick on the heat flux passing through the wall of a building on a sunny day in Medina, Saudi Arabia

In this article, the impact of using two types of phase change material (PCM) in brick on a summer day according to the climate of Medina, Saudi Arabia is studied numerically. Bricks with square holes filled with PCM are used for the inner sidewall. For this purpose, PCMs P116 and n-Eicosane are used to fill the bricks and are compared with the case without PCM to determine its effect on the amount of heat flux passing (HEFP) through the wall. The effect of the different number of holes (1–4) is also studied. Two-dimensional numerical simulations are performed using the control volume method. The results show that the maximum HEFP through the wall occurs in the afternoon. Examination of the melting front of PCMs indicates that the melting front moves from the hot wall toward the cold wall and the type of PCM are important during the completion of the melting process. In general, the usage of PCM minimizes the amount of HEFP through the wall. The usage of PCM n-Eicosane results in a greater decrease in the quantity of heat flux going through the wall. At midday, the biggest drop in heat flow occurs. Using additional holes, particularly when the bricks are filled with PCM n-Eicosane, dramatically lowers the HEFP through the wall. The kind of PCM used to decrease flux going through the wall is determined by the temperature of the building.

Thermal control of crystalline silicon photovoltaic (c-Si PV) module using Docosane phase change material (PCM) for improved performance

As crystalline silicon photovoltaic (c-Si PV) module demonstrates circa 0.45% drop in conversion efficiency for every 1 °C cell temperature rise above 25 °C standard test condition (STC), thermal control of the system is critical to improving its efficiency especially for elevated temperature climate deployment. This research demonstrates the utilisation of Docosane C22H46 paraffin wax phase change material (PCM) to lower the operating temperature of c-Si PV module operating in hot climatic conditions. Employing computational fluid flow fluent analysis in Ansys software package, the thermal responses of finite element (FE) models of the module to environmentally induced loads are simulated for 24-hour period. The results are validated analytically. Findings reveal that temperature difference between ambient and solar cell is maximum at noon at 23.7 °C and monotonically decreases afterwards to zero at 6.00 am and 8.00 pm. The implementation of PCM delivers a PV-PCM module that is 10.88% more conversion efficient than the conventional c-Si PV module. Further findings show the improved efficiency results from PV-PCM module achieving cell temperature reduction of 78.4% at peak heat flux and 31.1% overall. The PV-PCM module produces 6.1% more voltage, 2.1% more electric power and 8.1% more maximum power daily than the conventional c-Si PV module. In addition, it is found to be 1.05% more efficient and has 34.0% longer fatigue life. The PCM usage demonstrates effectiveness in control of thermal characteristics of c-Si PV module by improving its performance – crucial for its reliable operations in hot climates.

A comparative study of various fatty acids as phase change material to enhance the freshwater productivity of solar still

The scarcity of potable water due to rapid growth in population, industrialization, and the continuous extraction of groundwater has led to an impending crisis. Researchers have invented numerous techniques to obtain freshwater in order to fulfill the increased requirements, and solar desalination using a solar still is one of the low-cost methods to generate freshwater. In a solar still, the usage of PCM (Phase Change Material) storage under the absorber plate enhances the productivity during the nighttime so that the still continues to generate freshwater even in the absence of solar energy. The present study undertakes the experimental, energy, exergy and economic analysis for a conventional solar still and solar stills using different types of fatty acids as PCM storage along with pin fins for enhanced heat transfer. For a comparative study of different organic fatty acids as PCM storage materials- lauric acid, palmitic acid and stearic acid were used along with high-conductive aluminum pin fins which were inserted in the PCM storage to enhance the rate of heat conduction. The results obtained using the PCM along with pin fins were compared with the output from the conventional solar still (CSS). Thus, four different cases were considered for the current study, namely: the conventional solar still (CSS); the solar still with lauric acid and pin fins (SSLA); the solar still with palmitic acid and pin fins (SSPA), and, the solar still with stearic acid and pin fins (SSSA). The experiments were performed in the months of January (representing the winter season) and May (representing the summer season), at the location Gandhinagar, Gujarat (23.22°N 72.650°E), India, with variation in the depth of water (1 cm, 2 cm and 3 cm) in the basin of solar still. The accumulated productivity, energy efficiency, and exergy efficiency were observed as 4.43 L/m2, 47.9% and 2.23% for SSLA in January, which was the maximum amongst all cases in January. The accumulated productivity, energy efficiency and exergy efficiency were 5.74 L/m2, 56.2% and 2.96% for the case of SSSA in the month of May, which was the maximum amongst all the cases. The SSSA was the economical solar still amongst all cases; the payback period and cost per liter of SSSA were 72 days and 0.016 $/L/m2, respectively.

Thermal performance of phase change material embedded in building Wall- a numerical analysis

Due to the energy demand the Phase Change Material (PCM) is used in the building envelope to reduce the inner room temperature. The PCM plays an important role in Thermal Energy Storage (TES). So, the PCM is used in the construction for energy conservation. Mostly device, by using a comparatively high storing density, constant phase change temperature and latent heat property. PCM is potentially appropriate as construction material as it is possible to combine into the building covering used for energy management. The main objective of using PCM is to enhancing the thermal performance of building to maintain a human thermal comfort. Ansys Transient thermal is the selected software to simulate the PCM in the building envelope. In this article a detail discusses about the numerical analysis of building thermal features with PCM materials on the wall for climatical situations in Chennai. The n- Octadecane (C18H38), Calcium chloride hexahydrate (CaCl2·6H2O) and Sodium carbonate decahydrate (Na2 CO3·10H2O) PCM are used in this analysis. The numerical test results show that nearly 4 to 5℃ fewer temperatures throughout the diurnal in the PCM filled building model, related by the without PCM packed model. From the simulation result can concluded that the usage of PCM in the building wall will also decrease the energy consumption for cooling that chamber.

Enhancing thermophysical properties of phase change material via alumina and copper nanoparticles

The usage of phase change materials (PCMs) in thermal energy storage (TES) systems has been a promising approach in recent years. An accurate estimation of their thermophysical properties is a key factor in their optimal and efficient performance in TES systems. In this study, aluminum oxide (Al2O3) and copper (Cu) nanoparticles were incorporated in paraffin wax as a PCM to enhance its thermophysical properties. The effects of the nanoparticle type, mass fraction, and its size on the specific heat, density, thermal conductivity, and TES density of the nanocomposites, were investigated. A field emission scanning electron microscope (FESEM) was used to study their morphology. The experiments were based on three factors, nanoparticle type (Al2O3 and Cu), nanoparticle mass fraction (1%, 3%, and 6%), and nanoparticle size (30, 70, and 110 nm), while pure paraffin wax was applied as the control sample. The addition of nanoparticles to paraffin has been proven to be a promising technique. The results showed that the specific heat changes of the NePCMs have not been influenced by the factors under consideration. Also, higher mass fractions and smaller sizes of nanoparticles resulted in higher densities in NePCMs. Moreover, the thermal energy storage density of NePCMs increased at higher loading and smaller size of the nanoparticles. The improvement in thermal conductivity is especially significant if the smallest nanoparticle size with mass fractions of 3% and 6% is used. An improvement in thermal conductivity of up to 72% has been achieved at a mass fraction of 6% of 30 nm copper nanoparticles. Finally, the NePCM containing 6% mass fraction and 30 nm size of the nanoparticle (A6S and C6S) were selected as optimal NePCMs.

Design, development, and performance testing of thermal energy storage based solar dryer system for seeded grapes

The deterioration of food crops after harvest can be prevented using the appropriate drying method. Solar energy can be used in several beneficial ways, and a solar-aided dryer is one of the prominent applications. A forced convection medium-sized solar dryer with Phase Change Material (PCM) was designed and fabricated for conducting drying experiments. Organic paraffin wax, a PCM, was used for thermal energy storage in the solar dryer. The PCM will enhance drying efficiency even during off sunshine hours and reduce the overall drying period. The study compares the drying performance characteristics of seeded grapes between open sun drying, solar drying without and with PCM(100 and 200 g). The results of the drying experiments showed that grapes were effectively dried out using the PCM-based solar dryer. The grapes dried in a shorter duration using a solar dryer with 200 g of PCM compared with other drying methods. The grapes were dried out from an initial moisture content of 80.2% to a final moisture content of about 18.6%. The prototype model of the solar dryer with PCM was recommended to limit the use of the workforce, avoid improper drying, and reduce the overall drying period. An increase in the quantity of PCM in the solar dryer reduced the overall drying time of the grapes. The outcomes revealed that PCM usage helped retain the chamber’s heat for a longer time than the test without PCM.

Enhancement of the charging and discharging performance of a vertical latent heat thermal energy storage unit via conical shell design

Adopting phase change materials (PCMs), the latent heat thermal energy storage (LHTES) technology provides a potential solution to solve the fluctuation and instability of solar energy utilization. However, its applicability is strictly limited by the poor thermal conductivity of PCM. In this study, a novel shell structure of the LHTES unit was designed and optimized to enhance the charging and discharging performance. Verified by experimental data, a three-dimensional computational model considering the effect of natural convection based on the enthalpy-porosity method is established to simulate the melting and solidification processes of PCM. The results reveal that the melting time decreases with the increase of R/r (the ratio of the upper radius to the lower one of LHTES unit) until a nearly constant value is reached, while the solidification time first decreases and then increases. An optimum conical shell design was obtained based on the summation of melting and solidification time, which is independent on the inlet velocity and temperature of the heat transfer fluid (HTF). Although the deviation of heat stored or released varies little among different designs, significant reduction in the charging and discharging time is observed for the LHTES unit with the optimum conical shell if compared with the cylindrical shell under the same heat transfer area and PCM usage.

Battery Thermal Management System for electric vehicles using Phase Change Materials

Electric Vehicles (EVs) owing to their relatively low emissions and noise pollution are the most suitable alternatives for conventional vehicles. Lithium-ion batteries which are widely used in Electric Vehicles are meant to operate within a strict temperature range of 20 °C–50 °C Battery Thermal Management Systems (BTMS) plays a vital role in maintaining this temperature range, improving performance, service life and safety of the battery. Conventionally, there are two categories of BTMS, namely active cooling and passive cooling. Owing to the drawbacks such as power consumption and design complexities involved in active cooling, passive cooling techniques are increasingly gaining popularity. Passive cooling using Phase Change Materials (PCMs) are excellent candidates for BTMS application. PCMs have high latent heat and can absorb a large quantity of heat generated from the battery, with minimal change in temperature. Two PCMs (n-Docosane and Sodium Thiosulfate Pentahydrate) were chosen based on their properties such as melting temperature, Latent heat, Specific heat, Thermal Conductivity, Dynamic Viscosity and Density. This article also provides a methodology to optimize the usage of PCM for BTMS applications. While excess usage of PCM will add to the battery’s weight and also lead to ineffective use of PCM, using insufficient amount of PCM might lead to uncontrolled rise in cell temperature. This objective can be achieved by observing the trends of two specific output parameters – Mean Cell Temperature and Liquid Fraction derived from computational methods.