Phase Change Material Container Research Articles

Numerical simulation of various PCM container configurations for solar dryer application

In the context of solar dryers, where drying time is constrained by available sunshine hours and excessive heat during these periods can potentially lead to mineral loss in food, the incorporation of phase change material (PCM) for thermal energy storage emerges as a viable solution. However, the response time of PCMs plays a major role in its charging and discharging in solar dryer performance, prompting extensive research into PCM container configurations to reduce this limitation. Investigations have been conducted through numerical simulations and experimental studies to explore various configurations of PCM. In this study, four distinct container configurations were employed, alongside the introduction of fins, with two variations: solid and hollow. In this regard, Paraffin RT58, with its melting point closely aligned with the operating temperature of the solar dryer, is considered a suitable choice in simulation using ANSYS Fluent. The simulation results revealed that the horizontal rectangles demonstrate the quickest rates for melting and solidification, whereas the cylindrical shape exhibits the most extended durations for these processes. The introduction of fins has a notable impact on reducing both melting and solidification times, with a further decrease observed as the number of fins increases. While solid fins provide slightly superior reductions in melting and solidification times, opting for hollow fins presents benefits in terms of material efficiency, weight reduction, and cost savings.

Revolutionizing the latent heat storage: Boosting discharge performance with innovative undulated phase change material containers in a vertical shell-and-tube system

Abstract This paper examines the impact of various parameters, including frames, zigzag number, and enclosure shape, on the solidification process and thermal energy storage rate of a vertical phase change material (PCM) container. The study also assesses the effects of the flow rate of the heat transfer fluid as well as changing the materials of the PCM between RT35 and RT35HC. In addition, the study compares the framed versus unframed systems and, subsequently, the best case was tested with various zigzag pitch numbers before changing the zigzag-shaped structure to arc and reversed-arc. The findings are examined by contrasting the different scenarios’ liquid fractions, temperature distributions, solidification rates, and heat storage rates. The results show that the framed geometry is 66% faster to reach the target temperature compared with the unframed geometry and employing a zigzag enclosure in a PCM can significantly improve the solidification time and heat recovery rate. As the number of pitches in the zigzag enclosure increases, the improvement rate decreases but still improves the solidification time and heat recovery rate. The reversed-arc-shaped structure has the best performance compared with the other undulated surfaces. For the system with RT35HC, the discharge time is 55% higher compared with that of the system with RT35, while the discharge rate is 8.2% higher for the former during the first 3000 s of the discharging process.

Development of snow removal system using embedded pipes inside road with solar thermal energy collector and packed bed latent heat thermal energy storage

To enhance winter safety for drivers and pedestrians, this study developed and assessed an efficient snow removal system. Utilizing a packed bed latent heat thermal energy storage system with a solar thermal energy collector and phase change material (PCM), the research demonstrated performance over sensible thermal energy storage, offering increased storage capacity, isothermal characteristics, and efficient charging and discharging processes. In this study, a packed bed PCM container was proposed for the improved heat transfer performance of latent heat thermal energy storage (LHTES). The heat and fluid flow inside LHTES was numerically and experimentally analyzed for the optimization. The snow removal system comprised solar thermal energy collectors, a packed bed LHTES, and concrete pavement. As a results, the phase change material temperature increases from 30 °C to 75 °C during a 27-hour charging process, accumulating 58 MJ of thermal energy. The system's snow removal effectiveness was validated in an experiment, affirming the efficient transfer of stored heat to melt 10 cm-thick snow at −5 to 13 °C. Notably, no snow accumulation occurred on the concrete pavement surface.

A comprehensive experimental study of cooling photovoltaic panels using phase change materials under free and forced convection – Experiments and transient analysis

Solar radiation is captured by photovoltaic (PV) panels, which use it to create electricity. However, an overabundance of photons striking the PV's surface raises its temperature, which lowers its efficiency. These days, cooling solar panels is very important, and research on these methods is widely available in the literature. Thus, the study field's problems truly lie in developing new or improved methods for doing the same tasks. The goal of this work is to further boost the efficiency of photovoltaic (PV) panels beyond what can be achieved with PCM and free/forced convection alone. To do this, phase change materials (PCM) are cooled using both free and forced convection. In accordance with the latitude of Lebanon's Bekaa Valley, four cooling techniques are experimentally investigated. A photovoltaic panel using phase-change material (PCM) with copper and aluminum wires in a 70 %–20 %–10 % mass ratio (CPCM-PV), respectively, is the first cooling method. In the second approach, four 5 cm long fins are fixed under free convection using the same combination of aluminum fins inside the PCM container while preserving the same ratio (IEF-PCM-Free-PV). The third technique is the same as the second but with forced convection (IEF-PCM-Forced-PV), while the fourth technique uses an aluminum finned plate with 16 finned plates under forced convection (F-Forced-PV). IEF-PCM-Forced-PV showed the most relative increases in efficiency rate of energy dissipated of 20.36 % and 62.24 %, respectively, as compared to the regular PV panel, according to the results. F-Forced-PV, IEF-PCM-Free-PV, and CPCM-PV showed an increase in relative efficiency of 16.87 %, 6.3 %, and 3.9 % respectively, and correspondingly, these enhancements were accompanied by an increase in energy dissipation of 55.80 %, 44.85 %, and 41.18 % for each system. Economically, the IEF-PCM-Forced-PV had the highest total yearly savings of $17.87 with a payback period of 1.9 years. An appropriate transient energy balance is conducted and permitted to demonstrate clearly the transient behavior of the system under the various cooling techniques. Finally, the percentage of enhancement using the newly suggested composite PCM with internal and external fins under forced convection is compared to the enhancement found in the literature for various classical techniques and shows greater potential for further enhancement of the PV performance.

Enhancing Heat Storage Cooling Systems via the Implementation of Honeycomb-Inspired Design: Investigating Efficiency and Performance

This study presents a novel approach inspired by the hexagonal honeycomb structure found in nature, leveraging image processing algorithms to precisely define complex geometries in thermal systems. Hexagonal phase change material containers and thermally conductive fins were meticulously delineated, mirroring the intricate real-world designs of honeycombs. This innovative methodology not only streamlines setup processes but also enhances our understanding of melting dynamics within enclosures, highlighting the potential benefits of biomimetic design principles in engineering applications. Two distinct honeycomb structures were employed to investigate their impact on the melting process within cavities subject to heating from the left wall, with the remaining walls treated as adiabatic surfaces. The incorporation of a thermally conductive fin system within the enclosure significantly reduced the time required for a complete phase change, emphasizing the profound influence of fin systems on thermal design and performance. This enhancement in heat transfer dynamics makes fin systems advantageous for applications prioritizing precise temperature control and expedited phase change processes. Furthermore, the critical role of the fin system design was emphasized, influencing both the onset and location of the final point of melting. This underscores the importance of tailoring fin systems to specific applications to optimize their performance. Our study highlights the significant impact of the Rayleigh (Ra) number on the melting time in a cavity without fins, revealing a decrease from 6 to 0.4 as the Ra increased from 102 to 105; the introduction of a fin system uniformly reduced the melting time to Ste.Fo = 0.5, indicating fins’ universal effectiveness in optimizing thermal dynamics and expediting the melting process. Moreover, the cavity angle was found to significantly affect the fluid fraction diagram in unfanned cavities but had minimal impact when fins were present, highlighting the stabilizing role of fins in mitigating gravitational effects during melting processes. These insights expand our understanding of cavity geometry and fin interactions in heat transfer, offering potential for enhanced thermal system designs in various engineering applications. Decreasing thermal conductivity (λ) by increasing the fin thickness can halve the melting time, but the accompanying disadvantages include a heavier system and reduced energy storage due to less phase change material, necessitating a careful balance in decision-making.

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

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

Analyzing competing effects between heat transfer area and natural convection to enhance heat transfer in latent heat storage

Phase change materials (PCMs) are effective means of storing thermal energy and to balance temporal supply-demand mismatch. To enhance heat transfer within the PCM, internal fins are often employed to increase the heat exchange area, but they usually suppress simultaneously natural convection reducing the performance of the PCM storage. To better understand these two conflicting effects and to find a better trade-off between the different heat transfer means, a comprehensive numerical study of PCM storage with different fin shapes (straight and sinusoidal wavy fins) and surface areas, but with equivalent volume fraction, was accomplished. The results show that increasing the surface area of sinusoidal fins improves only marginally the heat transfer, mainly because the flow velocity of natural convection along the normal direction of the solid interface is inhibited. The velocity normal to the solid interface was found to be the most critical factors to the overall heat transfer efficiency of the system and to the time needed to complete the phase change in the PCM container. The study clearly shows that to enhance the heat transfer in PCM, the effects from natural convection (direction and strength) play a more important role than the heat exchange surface area. To improve the thermal performance and efficiency of PCM storage systems both factors need to be combined in an optimal way.

Optimization of Building integrated photovoltaic and thermoelectric hybrid energy harvesting system for different climatic regions

As energy saving emerges as a critical factor for the sustainable development of humankind, the importance of Zero-Energy Buildings (ZEB) is gradually increasing. Therefore, much research is being conducted on high-efficiency renewable energy technologies that can be applied in urban areas. However, increasing the efficiency of BIPV were proposed and studied because of the need for the renewable energy source. Such as using phase change material (PCM), heat fin, wavelength selection, PV surface temperature decreasing or using a thermoelectric generator (TEG), and convection cooling utilizing the waste heat from the PV. In most previous studies, the performance when each method was analyzed through experiments or simulations. However, the design analysis for maximum performance still needs to be conducted. Therefore, a BIPV combined with a PCM and TEG (BIPV-TEG-PCM) design is analyzed in this study. Herein, the three variables (phase change temperature of the PCM, heat fin spacing in the PCM container, and TEG arrangement) were analyzed through computational fluid dynamics (CFD)-based simulations. Moreover, through multi-objective optimization, the BIPV-TEG-PCM system of the optimal design was derived. Analysis results of the appropriate melting temperature of PCM, heat fin interval, and arrangement of TEG for the proposed system are 40 °C, 12.4 mm, and 187 mm, respectively.

Experimental studies on the enhancement in discharging characteristics of phase change material with steatite nanoparticles

Phase change materials are latent heat energy storage systems that can store huge quantities of thermal energy in a small volume. Latent heat energy storage systems are complicated to design due to the low thermal conductivity of phase change materials for discharging to enhance the heat capacity and latent heat storage. The objective of the study is to examine the discharging of phase change material in a latent heat energy storage system for maintaining the temperature of the water. Paraffin wax utilized as the phase change material due to its higher latent heat capacity. The experiments were performed with the flow of the hot water through a phase change material container by using a copper tube to enhance the discharging of phase change material during solidification to maintain the temperature of the water. Furthermore, the steatite nanoparticle has been dispersed with phase change material to enhance the discharging of characteristics. The steatite nanoparticle has been selected due to its low thermal conductivity, and the weight percentages nanoparticles were varied viz. 10 %, 20 %, 30 %, and 40 %. The increase in water temperature from 0.1 °C to 1 °C has been taken 7 h by enhancing the discharging of phase change material with various concentrations of the steatite nanoparticle. The work shows the significant discharging characteristics of phase change material with steatite nanoparticles. The nano-phase change material has the potential to maintain the temperature of water without any external energy for a particular duration, which shows cost-effectiveness.

Thermal and energy performance evaluation of a dry floor heating system based on hybrid heat storage aggregates for field application

The application of thermal energy storage (TES) systems in buildings has increased with growing interest in renewable energy technology. TES systems that use phase change materials (PCMs) are preferred over other energy storage methods. This study produced an activated carbon (AC)-based shape-stabilized PCM (ACS-PCM) using AC and n-eicosane, which was injected into a polyvinyl chloride (PVC) container to manufacture a heat storage container. The thermal properties of the ACS-PCM were analyzed to evaluate its performance when the manufactured heat storage container was applied to a dry floor heating system. Because of its high thermal conductivity, the ACS-PCM was superior to n-eicosane in heat transfer when heated. Moreover, the ACS-PCM exhibited a time-lag effect owing to heat storage during heating and free cooling. The PCM dry floor heating system consumed 77.3 % of the energy of the wet floor heating system. Finally, to increase the heat transfer efficiency, the ACS-PCM and pure n-eicosane were simultaneously injected into the PCM container to fill the gap between them; however, there was a temperature difference, highlighting the need for improved thermal conductivity of PCM container materials.

Efficient Power Conversion Using a PV-PCM-TE System Based on a Long Time Delay Phase Change With Concentrating Heat

Based on the characteristics of phase change concentrated heat, this paper proposes a photovoltaic/phase change/thermoelectric (PV-PCM-TE) self-supply system with sidewall integrated TE. In the system, an intelligent control circuit for phase change time is designed to intelligently switch the TE working mode using real-time temperature tracking. Therefore, the phase change time of the phase change material (PCM) is delayed with enhanced heat absorption and storage capacity, resulting in greater suppression of the PV temperature rise. Based on the constant temperature difference during the delayed phase change, more electrical power output can be obtained with integrated multistage thermoelectric generators (TEG) in the sidewall of the PCM container. With the supplementary TEG energy injected into the PV battery, a complete self-powered design is constructed, leading to improved system energy efficiency. Experimental results show that compared with the PV-PCM-TEG system, the PCM phase change time of the proposed system is extended by 15 min, where the peak PV temperature after suppression is only 68.5 °C, which is 8 °C lower than that of the conventional PV-TEG-PCM system. The conversion efficiency of the entire system reached 30.26%, an improvement of 43.15%. The proposed self-powered PV-PCM-TE power conversion system with a long-time delay and high efficiency can operate during both day and night, providing a green scheme for intelligent low-power electrical systems.

Battery thermal management of a novel helical channeled cylindrical Li-ion battery with nanofluid and hybrid nanoparticle-enhanced phase change material

Electric vehicles (EVs) have emerged as a viable alternative to Internal Combustion (IC) engine-powered vehicles, and efforts have been directed toward developing EVs that are more reliable and safer to operate. The safe working of EVs necessitates the use of an efficient battery cooling system. In this paper, cooling of cylindrical type Li-ion battery embedded with helical coolant channels is proposed. The effects of nanoparticles on removing heat from the battery cooling system have been investigated for four different nanoparticle concentrations: 0, 2, 5, and 10% of Al2O3 in the base fluid. Two cases of base fluids are considered: phase change material kept in a concentric container surrounding battery volume and coolant water circulated through liquid channels attached to the outer walls of the PCM (phase change material) cylindrical container. This study presented the three configurations (i) base case PCM-WLC: battery cooling system with a cylindrical enclosure filled with RT-42 phase change material. (ii) base case nePCM-WLC: battery cooling system filled with nano-enhanced phase change material. (iii) nePCM-LC: battery cooling system with helical liquid channels and filled with nano-enhanced PCM. The nanofluid was circulated through the liquid passages connected to the PCM container. Results showed using the helical channels, the nePCM-LC arrangement efficiently removes accumulated heat from the phase change material and provides better battery cooling than straight rectangular channel-based BTMS (battery thermal management system).

Geometry modification of a vertical shell-and-tube latent heat thermal energy storage system using a framed structure with different undulated shapes for the phase change material container during the melting process

This study aims to modify the melting performance of a vertical latent heat double-pipe heat exchanger by geometry modification of the phase change material (PCM) container. To modify the configuration of the PCM container placed in the outer tube, a framed structure is embedded in the inner surface of the outer tube. Different framed structures i.e. smooth, arc-shaped, reverse arc-shaped, and zigzag-shaped structures are examined and compared with that of the unframed enclosure. Moreover, different numbers of pitches are also examined. The results show that the melting duration drops by almost 55 % and the thermal energy storage rate improves by 115 % using a smooth framed structure for the PCM container compared with that of using an unframed structure. The thermal energy storage rate and melting time are ∼9.5 W and 244.4 min, respectively, for the system using an unframed structure. The analysis of the pitch number for the zigzag-shaped structure reveals that increasing the number of pitches from 0 to 11 enhances the thermal energy storage rate by 36.5 %. The evaluation of different shapes of the framed structure shows that the case with reverse arc-shaped structure is the most enhanced unit which has the thermal energy storage rate of ∼34 W and melting time of 63.15 min heated by water at the Reynolds number 1000 and inlet water temperature of 50 °C. The sensitivity analysis of the HTF characteristics reveals that by increasing the Re from 1000 to 2000, the thermal energy storage rate increases by around 6 W. Furthermore, by increasing the inlet temperature of HTF from 50 °C to 55 °C, the thermal energy storage rate enhances by around 10 W. This paper shows the capability of geometry modification in enhancing the thermal energy storage rate of the systems.

Numerical study on the influence of embedded PCM tubes on the energy storage properties of the geothermal energy pile

Geothermal energy pile is a remarkable alternative energy source that can provide heating and cooling energy to meet the energy demands in buildings. This study aims to quantify and expand the knowledge on the thermal storage performance of the geothermal pile system embedded with phase change material containers as compared to the one without, as a goal to expand the wide application of the system. In this study, numerical predictions were conducted on lab-scale energy pile systems, namely Design A (i.e., no PCM) and Design B (i.e., with PCM). The work aimed to investigate and quantify the energy storage properties of geothermal energy piles, and the influence of the incorporation of paraffin wax PCM tubes in the pile, at different flow rates. Incorporating PCM in a geothermal energy pile demonstrated considerable improvement in the amount of energy stored and extracted compared to the one with no PCM. For 735, 1470 and 2100 mL/min, Design B exhibited an increase in the energy stored by 42.21%, 44.71% and 46.23%, respectively compared to Design A. On the other hand, for the flow rate 735, 1470 and 2100 mL/min Design B illustrated an increase in the energy extracted by 45.87%, 53.09% and 59.55%, respectively compared to Design A. The use of PCM in the energy pile has a promising solution to enhance the storage capacity and improve the heat exchange capacity.

Performance optimization for a novel two-stage thermoelectric generator with different PCMs embedding modes

In this study, a novel two-stage TEG with different phase change materials (PCMs) embedding modes is proposed to improve the efficiency of TEG systems. The output power and electrical energy of single-stage and two-stage TEG combined with different PCMs is firstly compared at the limit of total length of the PCM containers. Furthermore, the effect of different PCMs embedding modes, including arranged at the heat source side, between two TEGs and heat sink side, on the performance of two-stage TEG system was discussed. Finally, the amount of different PCMs arranged at different locations was optimized. The results showed that although application of high temperature PCM on the heat source side can alleviate the effect of heat source fluctuations to provide more stabilized output power, the total electrical energy is seriously reduced in the two-stage TEG system. Compared with the single-stage TEG system, the two-stage TEG system provides a much higher output power and electrical energy, in which the harvested total electrical energy of the optimum two-stage TEG system is increased by 44.8% with a conversion efficiency of 6.9%. These results are of great significance to the design of advanced TEG system for waste heat recovery.

A numerical examination on the use of phase change materials to improve the sun-tracking photovoltaic panels' performance

The power generation of a photovoltaic (PV) panel is inherently affected by the amount of solar radiation striking the panel and the PV temperature. Tracking PV panels reach higher temperature than fixed panels due to more received radiation. Phase change materials (PCMs) are widely used as a passive method for cooling fixed PV panels. The melting dynamics of the PCM is very different during tracking compared to previous research carried out on fixed panels due to the changing orientation. A tracking PV-PCM system is numerically modeled in this research, and the temperature distribution and convection in the PCM are analyzed. The numerical results are presented as temperature-time curves for several different positions inside the PCM container, liquid fraction and streamlines in melted PCM, and isothermal curves. The temperature variation shows that the temperature of solid PCM increases rapidly in the initial time, reaching the melting temperature. The PCM changes from the solid phase to the liquid phase at a constant temperature. After complete melting, the PCM temperature increases over time. The PCM temperature changes were compared at two different distances from the photovoltaic panel. The streamlines show that the PCM starts to melt near the heated wall at the container's top corner. The melted PCM expands toward the down of the container due to vortex circulation created in the molten material. It is observed that the increase in PV panel temperature between 1.5 and 7 h is only 5.3 K, showing that using PCM is an effective method for absorbing heat from the PV panels during melting. Results show that the temperature of PV panel with PCM is on average 6.9 K lower than that without PCM.

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.

Experimental characterization, parameter identification and numerical sensitivity analysis of a novel hybrid sensible/latent thermal energy storage prototype for industrial retrofit applications

Hybrid design combinations of sensible and latent heat thermal energy storage (TES) leverage the advantages and reduce the disadvantages of both types. Thus, the range of application of said individual storage types is extended and crucial retrofit opportunities are enabled. Such hybrid TES concept consisting of a Ruths steam storage (RSS) and a surrounding layer of storage containers filled with an eutectic mixture of sodium nitrate (NaNO3) and lithium nitrate (LiNO3) as phase change material (PCM) was for the first time realized and investigated during operation in a steel production plant.In this work, the hybrid TES prototype is characterized with the help of detailed modelling and real measurement results. Uncertain model parameters are identified via parameter optimization and the numerical models show satisfactory validation results. Additional 30% of thermal energy could be stored in the PCM containers retrofitted to the lab-scale RSS. Charging/discharging times and specific thermal power of the PCM containers were roughly measured as 8h and 12h and 560kWm−3/−802kWm−3, respectively, in the typical operation region. A sensitivity analysis of the performance indicators reveals potential but also engineering challenges for following generations of the hybrid TES concept. Compared to the achieved experimental results, charging/discharging power could be increased by up to 10 and 5 times, respectively, in the future by adequate measures to increase heat transfer between both storage types.

A novel application of the geothermal asphalt pavement: A feasible E-fuel source

In this study, a novel application of geothermal technology was proposed and evaluated as a potential sustainable clean energy source. The proposed system incorporates thermoelectric generators (TEG) to transform the extracted heat from the pavement into electricity and enclose an enhanced geothermal system into the asphalt structure, intending to cool the pavement surface and provide the thermal gradient required for energy harvesting simultaneously. The study hypothesized the amplification of the thermal gradient through geothermal pipes embedded in the asphalt layer, a phase change material container in the subgrade, and an external cooling system in direct contact with the TEGs. A comprehensive experimental study was conducted to evaluate the thermal, electrical, and structural performance of the proposed geothermo-electrical asphalt pavement system. Also, a large-scale experimental physical model was established to simulate and assess the system's performance under real-life conditions. By monitoring the system's performance over six consecutive days, the results showed that the enhanced geothermal system efficiently reduced the surface temperature of the asphalt pavement by 40% and sustained a thermal gradient of around 40 °C, which was sufficient to sustainably harvest energy through using the TEGs. The harvested energy was then successfully used to charge an attached battery. The results of this study demonstrate the feasibility and potential of using geothermal technology in asphalt pavements as a sustainable energy source. Furthermore, the proposed system not only improves the performance of the pavements in terms of structural behavior but also introduces a new way of energy harvesting, opening the door for new possibilities in the renewable energy field.

Annual Thermal Management of the Photovoltaic Module to Enhance Electrical Power and Efficiency Using Heat Batteries

Several studies state that phase change material (PCM) improves the electrical power and efficiency of the photovoltaic (PV) module. To find the suitable PCM for tropical climatic conditions, multi-PCMs are examined simultaneously with melting temperatures of 31 °C, 35 °C, 37 °C, and 42 °C. In this study, PCM containers are integrated behind the PV module with a thickness of 50 mm. The performance of the multi PV-PCMs is monitored year-round and compared with PV-noPCM. The experimental results show that the selected four PCMs performed the cooling process autonomously in all the climates, such as PCM with a melting temperature of 37 °C and 42 °C enhanced the higher cooling rate in summer, and the same PCMs failed to achieve a higher cooling rate in winter. The lowest temperature drop was noted for pre-monsoon and monsoon seasons due to the low irradiance. On the other hand, the highest temperature drop of 16.33 °C is observed for pre-summer (March) and 15.7 °C, and 17.14 °C for summer (April) as compared to PV-noPCM. The results of the present investigation highlight the requirement for choosing the proper PCM melting temperature based on optimal year-round performance. Further, it is recommended that a single PCM melting temperature for cooling the PV modules year-round in tropical climates is inappropriate, and instead, a cascaded structure with different PCM melting temperatures is recommended.