Nanoparticles In Phase Change Material Research Articles

Examining the Thermophysical Impact of Low Concentrated Nanoparticles Hexagonal Boron Nitride Embedded in Phase Change Material for Photo to Thermal Energy Conversion

Phase change materials (PCMs) have garnered substantial interest for their use in thermal energy storage. However, restricted thermal conductivity of PCMs hinders their effectiveness in application. The objective of this work is to integrate hexagonal boron nitride (h‐BN) in low concentration with RT38 PCM for thermophysical characterization and photo to thermal energy conversion. The composites are prepared by adding 0.03–0.07 weight percent (wt%) nanoparticles with RT38 PCM through two‐step technique. As per the results, prepared samples remain chemically and thermally stable. Besides, addition of 0.05 wt% of h‐BN nanoparticles with PCM (RT38‐0.05) enhances thermal conductivity to 43%. Additionally, latent heat of melting remains at 137 Jg−1 for 0.05 wt% nanoparticle integrated nanocomposite in comparison to base 140 Jg−1 with slight variation in its melting temperatures. Further, PCM and nanocomposites exhibit zero weight degradation on thermal‐stability analysis up to 160 °C. The research examines thermal energy storage behaviour of base PCM and RT38‐0.05 nanocomposite by applying 800 Wm−2 irradiations. The analysis shows that RT38‐0.05 nanocomposite reaches 49 °C in 9 min, whereas base PCM achieves 43 °C. Thus, the integration of h‐BN nanoparticles in PCM results in improved thermophysical properties and greater conversion of photo to thermal energy.

Experimental exploration of nano-phase change material composites for thermal management in Lithium-ion batteries

The present study reports an experimental investigation carried out for the thermal management of cylindrical lithium-ion battery simulators using aluminum oxide (nano particle)-eicosane (phase change material) composites. The experiment involves varying the power input from 4 to 10 W in 2 W increments and adjusting the weight percentage of nanoparticles (wt%) from 0.5 to 0.9 in 0.2 wt% intervals. The examination of battery temperature evolutions in response to heating power, a comprehensive heat transfer analysis incorporating the Nusselt number, the determination of the maximum temperature difference, thermal resistance analysis, and the exploration of temperature variations in the absence of Phase Change Material (PCM) are considered. The results show that an increase in the weight percentage of alumina nanoparticles in phase-change material cannot always improve the thermal performance. The results of the present study give guidelines for designing battery thermal management systems. The power levels used in the experiment vary from 4 W to 10 W in steps of 2 W. For a power level of 4 W, the heat flux is 1.088 kW/m2, and for a power level of 10 W, the heat flux is 2.72 kW/m2.

Investigation of numerical phase transition of nano-enhanced SiC/paraffin wax PCM in solar-assisted water desalination system

Adding nanoparticles in phase change material (PCM) is a new trend for enhancing their thermal energy-storing ability as well as thermal conductivity. From this point of view, a numerical study is carried out to examine the addition of silicon carbide nanoparticles in paraffin wax PCM, used as heat energy storing material in a semi-cylindrical solar water desalination system. The PCM temperature is maintained at 52 °C and the semi-cylindrical tubular section has a wall temperature of 85 °C. The top plane section of the tubular solar collector is made up of graphite material. A semi-circular cross-section is selected for numerical analysis. A finite volume solver is used for solving thermal and fluid flow governing equations. A pressure staggering option algorithm is applied for pressure–velocity coupling. The temporal parameters like temperature, velocity contours, melting fraction, enthalpy, and entropy of nano silicon embedded paraffin wax PCM are widely discussed. The results clearly show that the phase transition of solid PCM to fluid PCM is greatly influenced by nanoparticle addition and enhances the rate of heat transfer. Initially for the first 60 min the melting fraction and temperature of PCM remain uniform as the time step increases above 60 min the behavior of PCM changes abruptly which clearly indicates the random distribution of nanoparticles within the PCM. A critical time and temperature limit exists for nanoparticles-based PCM beyond which, the thermal efficiency of the solar water desalination system gets influenced.

PERFORMANCE IMPROVEMENT OF CIRCULAR PARABOLIC CONCENTRATING SOLAR COOKER USING NANO-MIXED BINARY SALT PHASE CHANGE MATERIAL

A multi-objective investigation has been carried out for a parabolic concentrator-type solar cooker with the use of nano-mixed binary salts phase change material (PCM) materials. Binary salts like NaNO<sub>3</sub> and KNO<sub>3</sub> are mixed with alumina (Al<sub>2</sub>O<sub>3</sub>) nanoparticles in the ratio of 0.5%, 1%, and 1.5% by weight. Properties such as thermal conductivity, specific heat, melting point, and thermal diffusivity are computed experimentally. Two food items, namely rice and dal, are selected for cooking purposes. The experimental results obtained from this research work show some promising returns. As compared to the plain PCM, the nano-mixed PCM reduces the cooking time, and with an increase in the addition of nanoparticles in PCM, the overall cooking time for both food items decreases. A difference of 5-6 minutes has been observed between plain PCM and nano-mixed PCM cooking. Another important observation made during this study is that the thermal properties of PCM material are affected by the addition of nanoparticles. The thermal conductivity increases by almost 10% and thermal diffusivity increases by 20%. The melting point of PCM decreases by 22°C, and the specific heat decreases by 12% and 17% at a temperature of 100°C and 250°C, respectively. Finally, it is concluded that the use of alumina nanoparticles in the binary salts PCM improves the thermal storage capacity of the PCM material.

Impact of hybrid nano PCM (paraffin wax with Al2O3 and ZnO nanoparticles) on photovoltaic thermal system: Energy, exergy, exergoeconomic and enviroeconomic analysis

Global renewable energy efforts place a significant preference on substantial solar photovoltaic (PV) systems. Photovoltaic thermal (PVT) systems are the upgraded version of PV modules that concurrently produce both electricity and heat. Hybrid nano-particles (2.0 wt % ZnO and 2.0 wt % Al2O3) into the phase change material (PCM) known as HNPCM system has been introduced in this current study for enhancing the electrical and thermal performance of the PVT system by improving the thermophysical properties of paraffin wax as used for passive cooling. Three PV systems were compared in terms of performance: a conventional PV system, a PVT system using paraffin wax as a PCM (PVT/PCM), and a PVT system with 2.0 wt % of Al2O3 and ZnO in PCM (PVT/HNPCM). Upon investigation, the PVT/HNPCM system under outdoor environmental condition shows that the inclusion of different nanoparticles in PCM led to improvements in thermal and overall efficiency of 17.32 % and 13.82 % compared to PVT/PCM, respectively. This results in increase of electrical efficiency of 34.84 % when compared to conventional PV panel and incremental peak exergy efficiency of 36.47 %. Besides, for PVT/HNPCM, cost of electricity production ($/kWh) is almost 16.67 % less than the conventional PV configuration and the payback time is about 2.1 years on the overall exergy basis. Additionally, PVT/HNPCM system exhibits the long-term life cycle conversion efficiency compared to conventional PV panel and maximum sustainability index of 1.21 has been also found. Finally, the conclusion can be drawn positively for PVT/HNPCM as the most effective system from the exergy efficiency, exergy cost, and CO2 avoidance rates point of view.

Exploring the temperature-dependent thermal stability of nano-enhanced phase change materials: An experimental study using eicosane as the base material

Recently, studying phase change materials (PCMs) has brought many researchers' attention to be applied in thermal energy storage and battery thermal management (BTM) applications. Nano-materials have been used recently to improve the advantages of the PCM which makes them suitable materials to be used in thermal management systems. Moreover, the selection of the nanomaterials and the proper concentration of nano-particles in PCM affects the thermophysical characteristics of PCM. According to the fact that PCM requires to be thermally stable, the principal aim of this study is to analyze the thermal stability of PCMs composites by loading different mass fractions of CuO nano-particles. In order to add nano-particles to the eicosane-based PCM, a two-step method has been used. The thermal stability of the Nano-enhanced phase change materials (NePCM) has been measured by using the thermogravimetric analyzer. Results demonstrated that 0.5 wt% is the best value of additive nano-particle which showed a remarkable increment in thermal stability. Therefore, all the presented results indicate the importance of selecting an optimal PCM nano-composite for various applications including NePCM-based thermal energy storage and BTM systems. The brand and model of the device used in this study are Hitachi and STA7000 respectively.

Cesaro fins parametric optimization for enhancement in the solidification performance of a latent heat storage system with combined fins, foam, and nanoparticle

The use of Phase Change Materials (PCMs) for latent thermal energy storage enhances the availability of solar energy. PCMs can store a large amount of energy in a small volume using almost entirely isothermal processes. Despite this, the poor thermal conductivity of PCMs is a significant disadvantage of current PCMs, severely limiting their energy storage capabilities. As a result, the solidification/melting rates are reduced to an unacceptable level, and the system reaction time is increased unreasonably. By combining the novel fin arrangement, nanoparticles, and metal foam, the current study improved the solidification rate of the PCM in the Latent Heat Thermal Energy Storage System (LHTESS). LHTESS was numerically evaluated in ANSYS Fluent 18.1 using a solidification and melting model. The addition of cesaro fins, nanoparticles, and metal foam significantly improved PCM solidification in the LHTESS. PCM solidification time was reduced by 42.42% and 39.39% in Type-3 and Type-5 fin configurations, respectively, when compared to Type-4 fin configuration. Furthermore, a temperature difference of 27 K between the Heat Thermal Fluid (HTF) and the PCM ensures the best solidification performance. By incorporating nanoparticles into PCM and metal foam, the solidification time is reduced by 73.68%. Depending on the foam structure and volume fraction of the nanoparticles, dispersing nanoparticles in PCM with metal foam saves up to 75% of the time.

Effect of nanoparticle size during discharging of NePCM in TTHE: A numerical investigation

The addition of nanoparticles is an effective strategy to upgrade the thermo-physical properties of phase change material. This paper concerns the effect of nanoparticle size on the discharging (solidification) of nanoparticles enhanced phase change material in triple-tube heat exchanger. The commercial tool Ansys Fluent is used to create the two-dimensional numerical model. For solidification, enthalpy-porosity has been adopted, while the change in properties of the material due to addition of nanoparticles is defined by the user defined function. The size of nanoparticles is varied as 20 nm, 30 nm and 40 nm during the analysis. The model has been validated against the reported result in the literature. The results from the transient numerical analysis shows that the total discharging time being shortened by around 25% and 40% for the phase change material with 30 nm and 40 nm size nanoparticles respectively compared to the phase change material with 20 nm size nanoparticles. It is observed that the drop of average temperature during the discharging process increases while increasing the size of nanoparticles in phase change material.

Enhancement of phase change material melting using nanoparticles and magnetic field in the thermal energy storage system with strip fins

In this work, the numerical analysis of heat transfer and the enhancement of the melting of phase change material (PCM) in a three-dimensional cylindrical thermal energy storage system has been investigated. The RT82 is as PCM and the finite volume method is as the numerical solution method. Porosity-enthalpy method has been used to simulate the phase change melting process. The effects of strip fins, Fe3O4 nanoparticles, and uniform and non-uniform magnetic fields on the PCM melting are studied in details. Different modes have been considered for the non-uniform magnetic fields, both constant and variable with location. The predicted results display that the PCM melting time of the energy storage system using the new arrangement of strip fins is reduced by about 51 % compared to the that without fins. The addition of nanoparticles in PCM with volume fractions of 2.5 % and 5 % has improved the melting time by about 15 % and 22 % compared to those without nanoparticle. The use of a uniform magnetic field does not have much effect on the melting process without fins. But in the finned cases, in the initial melting (<1000 s), it has a noticeable effect on the amount of releasing energy in the desired system compared to the that without magnetic field, the mount of releasing energy is almost doubled. Using a variable magnetic field has a positive effect on the melting process of thermal energy storage and has improved the phase change process by about 39 % compared to the case without a field. It has also been concluded that in the case where the changes of the origin of the variable magnetic field (electric voltage) in the z-direction are parabolic, >60 % reduction in the melting time is noted.

Quantifying thermophysical properties, characterization, and thermal cycle testing of nano-enhanced organic eutectic phase change materials for thermal energy storage applications

Dispersion of highly conductive nanoparticles in Phase Change Materials (PCMs) tends to improve the thermophysical properties of nanocomposites. The current research condenses the synthesis, chemical, physical, and thermal characterization of novel nano-enhanced eutectic phase change materials (NeUPCMs) dispersed with TiO 2 nanofillers for thermal management applications. The base matrix primarily comprises of a eutectic of paraffin wax and palmitic acid. Detailed analysis of the uncertainty of each thermophysical property measured was performed. The synthesized nanocomposite logged a maximal thermal conductivity of 0.59 W/mK (2.3-fold as compared with the base-0.25 W/mK) with 0.5% nanofillers. The composites displayed excellent solar transmissivity (82%) as they were doped with nanofillers having a high refractive index. The latent heat of the NeUPCMs got enhanced by 17% whereas the melting point showed a slight decrement in nanocomposites. Further, zero phase segregation, no subcooling, stable phase transition temperature, and good chemical, and thermal stability were noted from digital scanning calorimetry results with NeUPCMs. The composites exhibited good thermal reliability beyond 500 thermal cycles. It could be potentially deployed in the thermal management of medium-temperature systems like PVT and LCPVT systems. • Novel nanocomposites were synthesized using paraffin wax, palmitic acid, and TiO 2 . • Nanocomposite had a maximal enhancement of 131.5% in thermal conductivity. • 38% rise in solar transmittance when compared with the eutectic base. • Thermophysical properties remained stable even after 500 thermal cycles.

Application of Artificial Intelligence to Improve the Thermal Energy and Exergy of Nanofluid-Based PV Thermal/Nano-Enhanced Phase Change Material

Photovoltaic-thermal (PVT) technologies have demonstrated several attractive features, such as higher power and comparative efficiencies. Improving the thermal recovery from the PVT system would further improve the power output and the efficiency of the PVT system. This paper identifies the best operating factors of nanofluid-based PV thermal/nano-enhanced phase change material using artificial intelligence. The target is the maximization of thermal energy and exergy outputs. The suggested approach combines ANFIS modelling and particle swarm optimization (PSO). Four operating factors are taken into consideration: PCM (phase change material) layer thickness, HTF (heat transfer fluid) mass flow rate, MFNPCM (“mass fraction of nanoparticles in PCM”) and MFNfluid (“mass fraction of nanoparticles in nanofluid”). Using a dataset, an “adaptive neuro-fuzzy inference system” (ANFIS) model has been established for simulating the thermal energy and exergy outputs in terms of the mentioned operating factors. Then, using PSO, the best values of PCM thickness, mass flow rate, MFNPCM and MFNfluid are estimated. The proposed model’s accuracy was examined by comparing the results with those obtained by response surface methodology and the experimental dataset.

Experimental investigation of eutectic phase changing materials (KCL + Na2SO4) mixed with graphene (Gr) nano-particles on refrigeration test rig

There has been increasing interest of various researchers in sustainable solutions towards HVAC and R. As we know that Indian refrigeration market has had remarkable growth of around 8.1 % Compound Annual Growth Rate (CAGR) over the period 2021–27. In India, several industries introduced deep freezers, refrigerators, refrigerated trucks for the preservation of different commodities like fruits, veggies, milk, Ice-cream, meat, medicines, etc., at 0 to 15 °C temperature. Thus, an attempt has been given on energy-saving opportunities for power saving by considering the above scope of refrigeration and cold chain applications. In this context, the present research is to prolong the cooling period during a power outage and minimize the losses which are occurred due to temperature fluctuations of the evaporator cabinet of the refrigeration test rig by using Nano-phase change material (KCl + Na2SO4 + Graphene) with water as base fluid. The experimental setup is tested during power ON and OFF conditions and performance is studied on the basis of cooling time, power consumption, and COP. The dispensability of nanoparticles and PCM is observed with the help of Scanning Electron Microscopy (SEM). The experiments were tested for 1 % and 5 % (KCl + Na2SO4 + Graphene) Nano-PCM mixture and it has been found that the addition of graphene nanoparticles in phase change material results in an enhanced heat transfer as well as improvement in 12 % COP. Also, power consumed with the advancement of Nano-PCM in the evaporator side is 10 % lesser than that of the conventional one. It is observed that with the use of 5 % (KCl and Na2SO4) addition of 1 % (Gr) with water as the base fluid it is possible to maintain 7 to 9 degrees for 13 to 15 hrs time span even though a power outage exists. The temperature range 5 to 10 degree is standard temperature for storing the fruits, veggies and medicine/vaccine. It is observed that thermal energy storage by using Nano-phase changing material for lower temperature application is the most appropriate way and method to correct the gap between the demand and supply of energy in cold chain applications.

Evaluation of efficiency of double slope solar still and drinking water yield using silver nanoparticle mixed with phase change material

ABSTRACT This study shows the contribution of silver nanoparticles mixed with macro-encapsulated phase change material (PCM) in a double slope solar still. Experiments are carried out in three different depths and settings, first using simple double slope solar still, then by addition of PCM, and finally using PCM mixed with silver nanoparticles. Results obtained are compared during the sunshine period and also after sunset. The study shows that the silver nanoparticles in PCM results in reducing the yield and efficiency of the double slope solar still by 7.64% and 5.26% during the charging period. However, it continues to deliver potable water even after sunset due to the stored latent heat in the PCM. The higher thermal capacity of the PCM and the higher thermal conductivity of the silver nanoparticles resulted in a 16% increase in drinking water yield and a 62.53% rise in the thermal efficiency of the double slope solar still. The final cost per liter of the potable water generated using the double slope solar still was reduced to 3.80 INR and the payback time is 2 years which can be reduced further using PCM and nano-enhanced PCM inside the solar still.

Impact of nano‐enhanced phase change material on thermal performance of building envelope and energy consumption

Using phase change material (PCM) in the building envelope can provide energy saving advantages by shaving peak heating and cooling loads. However, the poor thermal conductivity of PCMs limits their application and potential benefits because of inadequate heat storage/release rates. Increasing effective thermal conductivity by adding metal nanoparticles with high thermal conductivity to PCM (NPCM) could be a promising method to accelerate the phase change process, thereby exploiting latent heat more effectively. The potential impact of the utilization of NPCM technology has not yet been adequately explored for building external walls. This study aimed to reveal whether the dispersal of highly conductive nanoparticles in PCM in external building walls helps conserve energy or not. PCM enriched with aluminium oxide nanoparticles (Al2O3) with a content of 1, 2, and 3 vol% was used. The outputs showed that the nanoparticle addition decreased the energy-saving performance of PCM since the reduction in the thermal resistance and latent heat capacity caused by the nanoparticles loading was more profound than the enhancement provided by the improvement of latent heat exploitation caused by the increased thermal conductivity. For example, heating energy saving was reduced by 0.6% when a 3-cm PCM with 1 vol% Al2O3 was used instead of a pure PCM. The negative impact increased to 1.7% by increasing the nanoparticle concentration to 3 vol%. Thus, augmenting the thermal conductivity for higher latent heat activation by adding nanoparticles was not beneficial for building wall applications in a hot-summer Mediterranean climate. Highlights Effect of nanoparticle-enhanced PCM on building energy saving. PCM with Al2O3 content of 0, 1, 2, and 3 vol% embedded in external wall. Yearly energy saving of 20.7% was achieved with pure PCM in the wall. Adding 3 vol% Al2O3 to PCM reduced heating energy saving by 1.7%. Negative effect on energy saving increased with increasing nanoparticle concentration.

Phase change materials: Agents towards energy performance improvement in inclined, vertical, and horizontal walls of residential buildings

The numerical research of a wall (wall or ceiling) in the presence of phase change materials is undertaken in this work due to the relevance of energy consumption in buildings. One side of the wall has a high temperature, and the other side has a low temperature. The phase change materials is placed inside a cavity with an aluminum panel. For better examination, the number of cavities varies from 1 to 15 in the wall. The effect of different ceiling angles from 0 to 90° is evaluated. Graphene nanoparticles are added to increase the thermal conductivity of phase change materials, and the effects of varying the volume percentage of nanoparticles from 0 to 5% are explored. Finally, for phase change materials charging and discharging processes, as well as phase change time and wall temperature, a wall with variable numbers of cavities and angles for nano-phase change materials with varied volume percentage is simulated. The finite element method is used for the simulations by employing COMSOL. The findings of this research show that using nanoparticles in phase change materials decreases the melting time in the charging process and the freezing time in the discharging process, particularly with high volume percentages. Thus, in the cases of 1 and 15, a 5% enhancement in the number of nanoparticles in PCM intensifies the amount of molten PCM by 4.51% and 4.79%, respectively. The addition of nanoparticles also reduces the wall temperature. An increment in the number of cavities causes the charge and discharge processes to become faster. Further, it enhances the molten fraction of phase change materials in the charging process and the solid fraction of phase change materials in the discharging process.

Numerical investigation of nano-enhanced phase change material melting in the 3D annular tube with spiral fins

In the annular tube with spiral fins, adding the nanoparticles in phase change material (nano-PCM) can significantly improve the energy storage efficiency. The use of spiral fins coupled with nanoparticles could greatly broaden the application of PCM in the annular tube in the energy storage field. However, the energy storage process of nano-PCM in the annular tube with spiral fins is a research gap that has not been investigated before. In this study, the energy storage process and enhancement rate of this system are numerically investigated, which could provide a reference for the future design of this energy storage system. Results show that the melting rate of PCM added graphene is six times as fast as PCM added Al2O3 in the same situation. Adding 1% graphene into the PCM could significantly enhance the energy storage process. Increasing the volume concentration of nanoparticles of Al2O3 or graphene from 0% to 5% reduces the total energy storage capacity per unit mass of nano-PCMs to 16.53% or 10.87%, but increasing the spiral cycle (the distortion degree of the spiral fin) does not. With the synergistic effects of spiral cycle and nanoparticles, the maximum enhancement rates of energy storage of PCM added Al2O3 or graphene are 40.28% and 92.84%, respectively.

Nanomaterials based on phase change materials for antibacterial application.

Bacterial infections seriously threaten human health. Although antibiotics can significantly treat infectious diseases, antibiotics abuse has brought a series of serious problems, such as multidrug-resistant bacteria, adverse effects, and so on. Therefore, it is indispensable to develop alternative therapies with superior efficacy and minor toxicity to enhance the anti-infective outcome, overcome drug resistance and reduce adverse effects. The phase change material (PCM) is a substance that changes its physical properties with elevated temperatures. Nanoparticles based on PCM have been widely used in biomedical research due to their excellent biocompatibility, sustained release, and outstanding targeting properties. In this manuscript, the applications of PCM-based nanoparticles in the treatment of bacterial infections were summarized. Firstly, the composition and biotoxicity of PCM nanocarriers were described. Secondly, various antibacterial strategies based on PCM nanoparticles for combination therapy were highlighted. Finally, the prospects for antibacterial therapy of PCM nanomaterials were summarized.

Investigation of enhancement in the thermal response of phase change materials through nano powders

A major problem faced by Phase Change Materials (PCM) based latent heat thermal energy storage systems is the slow thermal response. In this study, the feasibility of nano phase change materials composites is investigated experimentally by using various types of nanoparticles in PCM, to improve thermal response by increasing the thermal conductivity. Heat transfer enhancement of PCM composites (RT26 and coconut oil) is achieved by acquiring better thermophysical properties through seeding nanoparticles in PCM. RT26 and coconut oil are beneficial due to the absence of corrosion to metallic containers. A thermal response investigation is conducted with a flat slab type latent heat thermal energy storage unit. It was observed that the increase in thermal conductivity of PCM by seeding nanoparticles is useful for the improvement of heat transfer. Carbon nanotubes have shown better performance as compared to Al2O3 and Fe3O4 nanoparticles. It was further analyzed that at a 1 wt percent concentration of nanoparticles, the maximum heat transfer enhancement in RT26 caused by Fe3O4, Al2O3 and carbon nanotubes nanocomposites is up to 20.01, 36.68 and 64.21% respectively. The maximum heat transfer enhancement in coconut oil caused by Fe3O4, Al2O3 and carbon nanotubes nanocomposites is up to 8.83, 14.84 and 33.38% respectively. Therefore, it is revealed that RT26 has more potential for heat transfer enhancement as compared to coconut oil. This is due to the percentage improvement in the thermophysical response of RT26 as compared to coconut oil. The economic and environmental analysis was conducted to compare the performance of latent heat thermal energy storage unit with and without the application of nanoparticles in PCM, to estimate the most viable candidate among various nano composites. The economic analysis presented the lowest annual energy running cost and Net Present Value(NPV) for nanocomposite of carbon nanotubes in RT26 is Rs.-4381 and RS.-36375 respectively. Whereas the maximum annual energy cost and NPV for pure RT26 are Rs.-12240 and Rs. -75548 respectively. The NPV for Fe3O4 and Al2O3 is Rs.-62207 and Rs.-53062 respectively. The cost and NPV were Rs.-6646 and Rs.-55226 in the case of carbon nanotubes in coconut oil. It shows that the trend is the same in the case of Fe3O4 and Al2O3 nanoparticles in both RT26 and coconut oil, unlike of carbon nanotubes. The environmental analysis shows that the maximum and minimum payments of carbon dioxide by carbon nanotubes and Fe3O4 nano composites respectively in RT26, are Rs.7000 and Rs.2176. While the corresponding values are Rs.2975 and Rs.798 in the case of coconut oil. Hence, carbon nanotubes in RT26 have the highest economic and environmental viability. Accordingly, the enhancement in heat transfer using these nanoparticles will be helpful in air conditioning applications like animal houses.

Thrombin Based Photothermal-Responsive Nanoplatform for Tumor-Specific Embolization Therapy.

The specific coagulation in the tumor vasculature has the potential for the ablation of solid tumors by cutting off the blood supply. However, the safe delivery of effective vessel occluding agents in the tumor-specific embolization therapy remains challenging. Herein, it is reported that the photothermal responsive tumor-specific embolization therapy based on thrombin (Thr) is delivered by intravenous injection via the phase-change materials (PCM)-based nanoparticles. The wax sealing profile of PCM enables safe delivery and prevents the preleakage of Thr in the blood circulation. While in the tumor site, the thermal effect induced by IR780 triggers the melting of PCM and rapidly releases Thr to generate coagulation in the tumor blood vessels. Based on the safe delivery and controllable release of Thr, thermal responsive tumor-specific embolization therapy could be achieved with high efficiency and no significant damage to normal organs and tissues. The safe administration of Thr to induce vascular infarction in tumors based on PCM nanoparticles in this work shows a promising strategy for improving the therapeutic specificity and efficacy of coagulation-based tumor therapy.

Evaluation and Improvement of PCM Melting in Double Tube Heat Exchangers Using Different Combinations of Nanoparticles and PCM (The Case of Renewable Energy Systems)

In this work, the melting process of phase change material (PCM) in double tube heat exchangers was investigated and evaluated through the use of different combinations (1, 2, 3% Nano-Enhanced PCM and 1, 3, 5% Nano-HTF) of GQD, as well as SWCNT nanoparticles and PCM (RT82). In this study, the effect of three different methods, namely the dispersion of nanoparticles in PCM (nano-enhanced PCM), the dispersion of nanoparticles in HTF (nano-HTF), and the simultaneous dispersion of nanoparticles in PCM and HTF (nano-enhanced PCM, nano-HTF) concerning the nanoparticles participation in the thermal energy storage system in a double tube heat exchanger was evaluated. Other effective factors, such as the inlet fluid temperature, different Reynolds numbers, fin as well as new parameter of pipe, and fin thickness were also evaluated. The results showed that the highest effect of different parameters on the PCM melting process was related to the 1% nano-HTF and 3% nano-enhanced PCM nanoparticles of SWCNT, which decreased the PCM melting rate by about 39%. The evaluation of the effect of pipe and fan thickness also showed that the melting rate improved by 31% through reducing the thickness of the HTF fin and pipe. In general, the current study followed two purposes first, to examine three methods of the dispersion of nanoparticles in the thermal energy storage system; second, to reduce the thickness of the tube and fin. Findings of the study yielded positive results.