Presence Of Phase Change Material Research Articles

Using a hybrid system to improve a lithium-ion battery in the presence of phase change material and the effect of air on the battery charge and discharge

In this article, a numerical analysis is done on the temperature of 4 plate-shaped battery cells with phase change material (PCM) chambers around each one in a rectangular shape. The batteries are placed in a channel with air flow. The study is done transiently in a time of 10 min. The batteries are of lithium ion type and the analysis is provided in two dimensions. The battery cells are arranged in the form of two single battery cells at the beginning, and end of the channel and two battery cells in the middle of the channel. These two middle batteries are placed in parallel. By changing the distance between the two middle batteries from two to three cm, this study is conducted to investigate the temperature of each of the four battery cells and changes in the amount of frozen PCM. Finally, the results showed that the temperature of the two batteries at the beginning and the end, increased continuously during the 10 min of the study. At a distance of three cm from the middle batteries, the lowest temperature occurred on the first and last batteries, while at the same distance, the highest temperature occurred on the middle ones. At a distance of two cm from the middle batteries, the lowest amount of frozen PCM was observed, while at a distance of three cm from the middle batteries, the highest amount of frozen PCM was found on the first and last batteries.

Two phase simulation of solar still in the presence of phase change materials in its bottom and aluminum nanoparticles in the water

This article performs a numerical study on a transient solar still (SOST) by utilizing a variable heat flux using COMSOL software. A phase change material (PCM) layer with a thickness of 10–50 mm is placed at the bottom of the desalination. Some aluminum nanoparticles are added to the water in the water desalination, and the two-phase method is used to simulate this part of the desalination water. Other variables include the angle of the glass that changes from 10 to 45⁰ and the heat transfer coefficient (HTFC) on the glass that varies from 5 to 300 W/m2. The effect of these variables on the average PCM temperature (T-PCM), PCM volume fraction (VOF-PCM), average moisture (AV-MO) temperature, and AV-MO concentration is examined in 12 h. The simulations are done using the finite element method (FEM). The results demonstrate that the average temperature and VOF-PCM, AV-MO concentration, and AV-MO temperature are enhanced from morning to noon and decreased from noon to evening. An increment in the thickness of PCM causes the VOF-PCM in desalination water to reduce by 35%. An enhancement in the glass angle reduces the average temperature of PCM, especially in the morning and afternoon. The change in PCM thickness, especially in the evening, significantly enhances the AV-MO temperature.

The impact of using a turbulator at the nanofluid flow inlet to cool a solar panel in the presence of phase change materials using artificial intelligence

Due to the importance of renewable energies in providing energy for the future of human beings, a simulation is performed in this paper on the nanofluid (NFD) flow inside a U-shaped tube placed under a solar panel (SPL). The tube is placed under the panel inside the enclosure containing phase change material (PCM). Alumina-water NFD and an organic PCM are used in this study. A turbulator (TBR) is utilized to improve the heat transfer (HTF) between the NFD flow and the SPL. This study is unsteady and is carried out at different Reynolds numbers (Res) to examine the effect of the TBR. The finite element method (FEM) is employed for the simulations and temperature-dependent relationships are used for the NFD flow. Finally, the best conditions are evaluated using artificial intelligence. The results of this study demonstrated that the use of a TBR causes the panel temperature (TPL) to reduce and the complete melting time of the PCM to enhance. The increment in Re entailed a reduction in the melting process of PCM and the TPL. The enhancement of Re increased the value of the HTF coefficient. Besides, the use of TBR enhanced the HTF coefficient. The minimum amounts of TPL and pressure drop correspond to the case when Re = 211 and the TBR is employed.

Investigation on Thermal and Electrical Performance of Late-Model Plate-and-Tube in Water-Based PVT-PCM Collectors

A large amount of redundant energy gained from incident solar energy is dissipated into the environment in the form of low-grade heat, which significantly reduces and limits the performance of photovoltaic cells, so removing or storing redundant heat and converting it back into available thermal energy is a promising way to improve the utilization of solar energy. A new combined water-based solar photovoltaic-thermophotovoltaic system embedded in the phase change material (PCM) mainly is proposed and designed. The effects of the water flow rate, cell operating temperature, the presence of PCM, and the thickness of the PCM factor on the overall module performance are explored comprehensively. The maximum thermal power output and the corresponding efficiency of the combined-system-embedded PCM are calculated numerically, The results obtained are compared with those of the PV (photovoltaic) and PVT(photovoltaic-thermal) cells with the same solar operating conditions. In addition, the PVT-PCM system possesses a higher power output and overall efficiency in comparison with the PVT and PV system, and the maximum cell temperature reduction of 12.54 °C and 42.28 °C is observed compared with PVT and PV systems. Moreover, an increased average power of 1.13 W and 4.59 in PVT-PCM systems is obtained compared with the PVT system and the PV system. Numerical calculation results illustrate that the maximum power output density and efficiency of the PVT-PCM are 3.06% and 16.15% greater than those of a single PVT system and PV system in the working time range, respectively. The obtained findings show the effectiveness of using PCM to improve power output and overall efficiency.

Effect of key parameters on the transient thermal performance of a building envelope with Trombe wall containing phase change material

The thermal behavior of a building envelope having a Trombe wall incorporating phase change material (PCM) is investigated during heating season, using experimentally validated 3D computational fluid dynamics (CFD) simulations. The effects of transient versus steady-state ambient irradiation and temperature, presence of PCM and different solar irradiation intensities on the spatial and temporal variation of temperature and airflow rate in the conditioned room are investigated. The results show that the flow transition and temperature rise mainly happen in the near-wall regions close to the room ceiling and in the air channel. They also indicate that the Trombe wall with PCM tends to prevent large fluctuations in room temperature and airflow rate. More importantly, it is determined that under constant radiation flux and ambient temperature, the PCM significantly improves the thermal performance of the envelope and effectively shifts the heating load, but under diurnally transient solar radiation flux and ambient temperature, these benefits seem less evident. Accordingly, caution must be exercised in extrapolating results obtained under constant ambient conditions to situations involving transient ambient conditions.

Applying machine learning based on multilayer perceptron on building energy demand in presence of phase change material to drop cooling load

In this study, by developing a multi-layer neural network, energy consumption in buildings with phase change material (PCM) was investigated. Three input parameters including transition temperature, setpoint, and PCM thickness were combined in a way that covers 324 different cases. The results of the neural network indicated that it is possible to predict the amount of cooling load with an accuracy of more than 95%. In a situation where the temperature is set at 20°C, if PCM with a melting point of 26°C is added with a thickness of 10 cm, the cooling demand experience a sharp decrease by 373.8 kWh/m2. Considering energy saving of 59.1 kWh/m2 for heating load, the annual energy demand of the building declined by 432.9 kWh/m2. As the setpoint increases, the effect of the phase change becomes more intense in heating demand than in cooling one. At a setpoint of 28°C, only the PCM with a phase change temperature of 29°C is useful and in this case, the cooling/heating loads are reduced by 242.7 and 218 kWh/m2 which resulted in annual energy saving of 460.7 kWh/m2. The neural network showed that if the internal temperature is adjusted between 22 and 28°C, the phase transition of 29°C is the most suitable case.

Energy and exergy analysis of an unglazed transpired collector connected to a dryer with a porous plate and phase change material

In the present work, an experimental study was performed by designing and constructing an unglazed transpired solar collector connected to an indirect solar dryer with a new design equipped with a porous plate and phase change material. Teucrium polium was considered to analysis the drying process. The experiments were conducted at two airflow rates (0.0125and 0.015kg/s) for the drying system with and without phase change material. The results implied the use of phase change material reduced the temperature of the drying chamber during the day (approximately 0.5 to 2.5°C) compared to the collector without phase change material. In the afternoon, it increased due to presence of phase change material in the porous plate and releasing the stored thermal energy. At the airflow rate of 0.0125 kg/s, without phase change material, the highest outlet temperature of the collector was 68.8°C. Moreover, using phase change material reduced the specific energy consumption from 12.25 to 11.05 MJ/kg and the overall efficiency in the drying process increased from 39.48 to 42.54 %. Using phase change material increases the exergy efficiency by about 6 %. The maximum energy efficiency for unglazed transpired solar collector (about 45.92%) was related to a mass flow rate of 0.015 kg/s with phase change material. Besides, the color changes for Teucrium polium dried by solar dryer with and without phase change material were about 19.42 and 21.26. Thus, it can be expressed that the use of phase change material improved the drying and thermal efficiency and color of the dried product.

Investigation Enhancement of Solar Still by Analysis Heat Transfer with Fresnel Lens and Phase Change Materials

One of the major issues facing the globe today is the lack of access to clean drinking water. Due to causes like population expansion, industrialization, urbanization, etc., water contamination significantly rises. Desalination has occasionally seen the development of a number of innovative methods, while solar distillation is thought to be more cost-effective. In this study, a steps distillation basin slope single basin solar still was used to examine the effect discusses the transformation of salt water into drinkable water by the Fresnel lens. When distillers were used with phase change materials, the temperature increased than it was without phase change materials, by increasing the working hours of the distillers, and thus increased productivity. But when distillers were used with phase change materials and a Fresnel lens, the productivity increased than it was due to the increase in temperature, as well as increased evaporation of water, as well as increased work The distiller works at night due to the presence of phase change materials, and thus the productivity of the distiller increased than it was before the lenses were placed. The outcomes demonstrate that the employment of Fresnel lenses and phase change materials can successfully transform salt water into drinking water.

Thermal management of lithium-ion battery in the presence of phase change material with nanoparticles considering thermal contact resistance

This work is devoted to investigating the thermal management of a lithium-ion battery during four stages of charging and discharging in the presence of phase change material. In this regard, the phase change material is located between the battery and ambient temperature considering thermal contact resistance. The analytical solution calculates the temperature jump at the interface between the battery and the phase change material to validate the numerical results under non-melting conditions. The lattice Boltzmann method is used to cover the momentum and energy equations with two relaxation times preventing numerical diffusion in the solid-liquid interface. Also, copper oxide nanoparticles in the range of 1 % to 5 % have been used to enhance the thermal conductivity of the phase change material. It is found that the maximum temperature of the battery in the absence of phase change material increased by 17 %, while it increases only by 1.7 % in the presence of phase change material when the ambient temperature changes from −20 to 50 °C. Results show that in conditions where there is complete melting, increasing the thickness of the phase change material causes a decrease in the maximum temperature of the battery. Also, it is shown that increasing the contact thermal resistance increases the maximum temperature of the battery and decreases the liquid fraction so that when the resistance reaches 0.0052 Km2/W, the maximum temperature of the battery increases by 1.1 °C, and the liquid fraction decreases by 11.23 %. Moreover, adding 5 % copper oxide nanoparticles to the phase change material reduces the battery temperature by 1 °C and increases the liquid fraction by 15.17 %.

Enhanced Energy Storage Using Pin-Fins in a Thermohydraulic System in the Presence of Phase Change Material

Energy storage has been an essential topic in thermal management. With the low conductivity of phase change material, the effort is to propose the best mechanism for heat transfer. In the present paper, pin-fins are used in the hydraulic system to transfer the heat coming from wastewater management into phase change material. Different flow rates have been tested, and it was found that pin-fins can create mixing in the flow chamber allowing a large convective heat flux to move heat into the phase change material. In the present design, it was found that natural convection assists in heat transfer. Additional findings suggested that the pin-fins height influence the heat transfer process. In the current configuration, 5 mm in height pin-fins demonstrated the best heat transfer when compared to pin-fins varying from 1 mm to 6 mm, respectively.

Machine Learning-Based Approach for Modeling the Nanofluid Flow in a Solar Thermal Panel in the Presence of Phase Change Materials

Considering the importance of environmental protection and renewable energy resources, particularly solar energy, the present study investigates the temperature control of a solar panel using a nanofluid (NFD) flow with eco-friendly nanoparticles (NPs) and a phase change material (PCM). The PCM was used under the solar panel, and the NFD flowed through pipes within the PCM. A number of straight fins (three fins) were exploited on the pipes, and the output flow temperature, heat transfer (HTR) coefficient, and melted PCM volume fraction were measured for different pipe diameters (D_Pipe) from 4 mm to 8 mm at various time points (from 0 to 100 min). Additionally, with the use of artificial intelligence and machine learning, the best conditions for obtaining the lowest panel temperature and the highest output NFD temperature at the lowest pressure drop have been determined. While the porosity approach was used to model the PCM melt front, a two-phase mixture was used to simulate NFD flow. It was discovered that the solar panel temperature and output temperature both increased considerably between t = 0 and t = 10 min before beginning to rise at varying rates, depending on the D_Pipe. The HTR coefficient increased over time, showing similar behavior to the panel temperature. The entire PCM melted within a short time for D_Pipes of 4 and 6 mm, while a large fraction of the PCM remained un-melted for a long time for a D_Pipe of 8 mm. An increase in D_Pipe, particularly from 4 to 6 mm, reduced the maximum and average panel temperatures, leading to a lower output flow temperature. Furthermore, the increased D_Pipe reduced the HTR coefficient, with the PCM remaining un-melted for a longer time under the panel.

Halloysite based geopolymers filled with wax microparticles as sustainable building materials with enhanced thermo-mechanical performances

This work proposes a novel protocol for the fabrication of halloysite based geopolymers filled with beeswax microparticles obtained from Pickering emulsions. The actual filling of the microwax into the geopolymers has been demonstrated by using several techniques, including thermal analyses, spectroscopies, microscopies and contact angle experiments. According to the morphological and structural investigations, microwax spherical particles (diameter ranging between ca. 3 and 5 µm) have been homogeneously dispersed within the geopolymeric network conferring excellent properties to the hybrid geopolymers in terms of mechanical performances and heat storage capacity although their low content in the hybrid material. For comparison, we have prepared and characterized hybrid geopolymers obtained by the loading of variable amounts of beeswax within the geopolymeric matrix. Reliable enhancements of the flexural characteristics and heat absorption capacity have been achieved only with a large content of beeswax. Moreover, the removal of microvax and wax from the hybrid geopolymers has been obtained by rinsing with ethanol. The washed geopolymers have been characterized by wettability and water vapour permeability experiments, which have been proved that the beeswax has been removed and the porosity of the materials can be controlled by the initial composition of the hybrid geopolymers.In conclusion, this paper puts forward an easy strategy to fabricate composite geopolymers with heat storage capacity due to presence of phase change materials (microwax particles) confined in the geopolymeric network. Their enhanced flexural performances make the hybrid geoppolymers suitable as building materials.

Impacts of phase change materials on performance of operational peak load shifting strategies in a sample building in hot‐arid climate

AbstractBuildings consume around 32% of the produced energy, worldwide and around 19% of the greenhouse gas emissions are related to them. It makes the buildings one of the largest energy consumers and one of the major sources of greenhouse gases emission. HVAC systems are one of the largest consumers of energy in buildings. In hot arid climates, cooling systems used in buildings impose a large pressure on the power grid, which may lead into blackouts. In order to address this problem, several approaches have been examined. Thermal energy storage, in particular, latent heat storage using phase change materials (PCM) has been notably considered in construction applications because of high energy storage densities. In this paper, the effect of using PCMs on energy consumption and peak load demand of a sample building is studied. Besides, impacts of precooling as a peak load shifting strategy is also investigated in presence of PCMs on the energy consumption of the sample building. The study was carried out for the weather condition of Kerman, Iran and the simulation is performed by TRNSYS software. Three types of phase change materials were investigated for two different scenarios. The simulation was performed at two stages and two modes for each stage which each mode had its own set point temperature. The application of PCMs was considered at the first stage and precooling added to the simulation at the second stage. The results of the first stage showed that employing PCMs in the studied building reduces the cooling load up to 13%. With precooling, the cooling load reduction was up to 16%. At all stages peak loads decreased with maximum 14% at the first stage and 42.5% at the second stage. It has been showed that the solid–liquid phase change temperature of the PCMs close to the selected room temperature, have significant impact on the performance of PCMs for reducing the energy consumption of the sample building compared to the other thermal properties. Due to the low electricity prices in Iran, despite the high amounts in load reduction achieved by each strategy, the cost savings during hot months of the year was not significant.

Thermal performance assessment of phase change material for electronic cooling: An experimental investigation

AbstractIn the present study, an experimental investigation is performed to check the performance of phase change material (PCM) OM42 for passive electronic cooling applications. Rectangular fins were used as PCM thermal conductivity enhancers (TCEs) to enhance the thermal conductivity of PCM. The experiments were performed (a) by maintaining the required input heat flux to the heater and (b) by maintaining the set point temperature (SPT) of the heater. The heater wattage controller was used to supply the required power to the heater and thermostat W1209 was used to control the SPT of the heater. The experiments were performed in the combination of PCM and fins, with fins only, With PCM only, and with PCM and fins. The obtained results signify improved performance of the heat sink when PCM with fins was used. At input heat flux of 1, 2, 3, 4 and 5 kW/m2 the heat sink reaches the critical temperature in 80, 60, 55, 50 and 40 minutes respectively in the absence of PCM without fins, but with the presence of PCM without fins and PCM with fins, the heater sink is well below the critical temperature for a complete charging cycle. At input heat flux of 4 and 5 kW/m2, the intensity of PCM melting rate is faster and hence solid‐liquid interface decreases quite rapidly as the buoyancy force dominates the viscous force since the volume of liquid PCM rises as the natural convection effect increases in the liquid region.

Sustainable and renewable energy management by investigating the effect of the diameter of finned tubes of a solar collector on its heat production in the presence of phase change materials in a residential building

This paper examines a flat-plate solar panel numerically. Phase change material (PCM) is used at the bottom of the collector to store solar energy. Three tubes are placed inside the PCM, on each of which a number of fins are installed. A transient study is performed in a period of 1000 s for three tube diameters of 4, 6, and 8 cm. The aim is to evaluate the collector temperature, PCM phase, water inlet temperature, and the amount of thermal energy generated by the collector for domestic hot water. This numerical study is done using the finite element method. Using a larger diameter can cool the collector but make the outlet water temperature slightly lower. The use of tubes with 4 and 6 cm in the collector causes the whole PCM to become molten in a short time, but the use of a tube with 8 cm causes the molten PCM to remain constant for a while and no other phase change occurs in the PCM, resulting in some of the PCM remain solid. A tube with a diameter of 8 cm can generate the maximum amount of heat in the collector and the maximum amount of heat received from the sun is 483 W.

Using phase change material (PCM) to improve the solar energy capacity of glass in solar collectors by enhancing their thermal performance via developed MD approach

One of the key ways to improve energy storage performance is to use advanced materials and elements in building coatings. Dense exterior walls with high thermal insulation properties and absorbent and heat-retaining elements can be made by intelligently combining products to store latent heat based on PCMs. In the present study, the thermal behaviour of glass in the presence of PCM (Decane) has been investigated by molecular dynamics simulation. In this paper, the atomic behaviour of the structure is investigated by temperature and density profiles. And the thermal behaviour of the simulated structure is investigated by heat flux and thermal conductivity. The numerical results show that the maximum density and temperature in fluid particles are 0.09643 atom/Å3 and 1067.51 K. The structure's heat flux and thermal conductivity reach 650.27 W/m2 and 0.74 W/m.K, respectively. In general, the use of phase-change materials can prevent energy loss, reduce energy costs, and while changing the phase of materials, quickly has a positive effect on the appearance of the building (as a result of beauty and performance, which are an integral part) Will leave.

Loading phase change material in a concrete based wall to enhance concrete thermal properties

In this study, energy analysis was performed to improve the thermal behavior of the concrete-based wall of the building in the presence of phase change material (PCM). PCMs have low conductivity, acceptable specific capacity, and high latent enthalpy, which makes them a superior candidate for building applications. Considering the thermal properties of concrete in the range of 100–200 mm, PCM was added to the concrete. At concrete thickness of 100 mm, the impact of PCM was maximized so that the combination of PCM with concrete significantly reduced heat load (by 71.5%) as well as cold load (by 61%). Annual analysis showed that in the concrete thickness of 100 mm–200 mm, the presence of PCM reduces energy demand. At a thickness of 100 mm, the energy consumption was reduced by 64.1% while at the thickness of 150 and 200 mm, energy demand reduction was 59% and 56.8%. Due to loading PCM into concrete, an annual energy-saving of 231.6 kWh/m2 at the concrete thickness of 100 cm was achieved. This value at 150 cm and 200 cm was 176.5 and 156.3 kWh/m2, respectively.

A study of nanoparticle shape in water/alumina/boehmite nanofluid flow in the thermal management of a lithium-ion battery under the presence of phase-change materials

The passive method of using phase-change materials (PCMs) and the active method of using forced nanofluid flow are employed to control the temperature of a battery pack. The battery pack is of the cylindrical lithium-ion (Li-ion) type and in the form of a cubic pack. The PCM used occupies the whole space in the cube. The nanofluid flows in a helical channel inside the battery pack. Water/alumina/boehmite was used as the nanofluid with different nanoparticle shapes. Parameters such as the temperature of the battery and the heat transfer coefficient (HTCO) were numerically studied by varying the nanofluid velocity. COMSOL software is used to simulate the battery pack and the nanofluid flow inside it. The major results indicated that the blade-shaped nanoparticles led to the largest drop in the maximum (MAX) temperature and the amount of molten PCM at different times compared to other nanoparticle shapes. Increasing the nanofluid velocity from 0.02 to 0.06 m/s reduced the amount of molten PCM by 4.7% and resulted in a 70% increase in HTCO nanofluid. In addition, this rise in velocity reduced the MAX and average (AVG) temperature of the battery by 1.24 °C and 1.53 °C, respectively, and decreased the outlet nanofluid temperature by 0.44 °C.

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.

Challenges in incorporating phase change materials into thermal control units for lithium-ion battery cooling

Keeping cool the lithium-ion battery improves its performance. In this study, focusing on battery cooling, a thermal control unit (TCU) containing metal fins was integrated into the battery. To boost TCU effectiveness, phase change material (PCM) was injected into it. By numerical solution, the temperature distribution in three areas of battery, fins and PCM was determined. Using Fourier's law, TCU heat dissipation to the environment was evaluated at different convection coefficients (5, 10, and 20 Wm2.K). It was observed that the presence of PCM is not always advantageous. The presence of PCM can only be useful if the PCM undergoes phase changes. This happened at 5 Wm2.K, and at best conditions, the battery temperature dropped by 8°C due to the PCM presence. After the melting process, the PCM presence significantly augmented the battery temperature. At 20 Wm2.K battery temperature was increased by 4.8 °C when PCM was loaded into TCU. Therefore, adding PCM to TCU with convection coefficient is not recommended. Increasing the number of fins declined the battery temperature. If the number of fins increases from three to five, the battery cooled by 1 to 1.7°C at convection coefficient range of 5–20 Wm2.K