•Battery cooling system is modified with phase change material.•Novel cell-to-cell air cooling provides temperature rise less than 5 °C.•Cell-wise phase material cooling maintains temperature ...uniformity within 0.12 °C.•Modular arrangement simplifies capacity build-up and replacement of faulty cell.•Conjugate active and passive cooling reduces the maximum temperature in module.
In a conventional system, the cells of the entire battery pack are sandwiched in a single phase change material (PCM). The PCM material confining the corner cells may reject heat at a faster rate to the adjoining ambient air as compared to the cells located in the middle of the pack. In this work, the conventional battery layout system is modified to induce active and passive cooling for each cell of a battery module. For this, battery pack is arranged into several modules; each module comprised of six cylindrical cells in a 1S6P arrangement. Each cell is placed in a 4 mm cylindrical gap enclosure filled with phase change material and interconnected together for further cooling at inter-spacings. Cooling performance of such modified layout is reported at different discharge rates (2C and 4C) and ambient condition (27 °C, 35 °C and 40 °C). It is found that confined phase change material around each cell help in better heat dissipation from PCM and improved temperature uniformity in the module.
•Optimisation of PCM based cooling coupled with liquid cooling system.•System weight and consumption of different configurations is evaluated.•Suggesting a 2-sided cold plates hybrid system for BTMS ...of pouch cells.•Suggested hybrid BTMS can withstand cell-to-cell variation of battery cells.
In this paper, a novel design for hybrid battery thermal management systems (BTMS) is proposed and evaluated from the economic and engineering perspectives. Numerical models are compared with phase change materials (PCM) BTMS. Further, the suggested hybrid cooling system’s thermal performance at the pack level is investigated considering cell-to-cell variation. A three-dimensional thermal model is used for the numerical simulation of the battery cooling system. The probability distributions is utilised for the cell-to-cell variations of a 168-cell battery pack. Results shows that for a 53 Ah lithium-ion battery (LIB) under a 5C discharge rate, a hybrid cooling system with two-sided cold plates can reduce the maximum temperature from ∼64 ∘C to 46.3 ∘C with acceptable system weight and power consumption, which is used for further pack level simulation. It is concluded that the two-sided cold plate hybrid design system can manage the maximum average temperature as well as temperature difference of cells in the desirable range at extreme cases.
•The performance of a photovoltaic-thermoelectric hybrid system is investigated.•An integrated phase change material/cobalt oxide nanofluid heat sink is proposed.•Around 14% higher electrical power ...is experimentally achieved by this heat sink.•The exergy efficiency of the unit is improved by 17.8% at noon.
Nowadays, photovoltaic panels have been known as effective devices to harness solar energy. These panels mainly convert the UV and visible areas of the solar spectrum into electricity and the rest of the energy is dissipated. One of the favorable methods to take advantage of such dissipated heat is to combine thermoelectric generators (TEG) utilizing the IR area of the solar radiation with photovoltaic panels. Having the different and opposite impact on the efficiency of thermal photovoltaic cells (PV/T) and thermoelectric generators (TEG), the system operating temperature appears as a critical parameter in the productivity of a PV/T-TEG hybrid unit. In the present study, a novel heat sink for a PV/T-TEG hybrid system is introduced. The effectiveness of simultaneous usage of the Co3O4/water nanofluid and the improved phase change material (paraffin wax/Alumina powder) as a cooling method on the performance of the PV/T-TEG is examined throughout an experimental study. Then, the overall electrical, thermal and exergy efficiency of such a system is compared to the units with divers working fluids including water and 0.25%, 0.5%, and 1% nanofluid and the unit consisting of 1% nanofluid with non-enhanced PCM cooling method. The results reveal that using 1% nanofluid with enhanced PCM, as a cooling method, would improve the overall electrical efficiency by 12.28% compared to water cooling technique. Also, an increase of 11.6% in the exergy efficiency of the PV/T-TEG is observed in comparison with PV/T-TEG with the water cooling method. Hence, it could be concluded that the combination of this unit could contribute to harnessing solar energy more efficiently, compared to solo photovoltaic panels.
•Inclusion of n-eicosane reduces temperature more significantly than paraffin wax.•A higher latent phase completion time was found in case of 3mm diameter pin-fin.•A higher enhancement in operation ...time is obtained in case of 3 mm diameter pin-fin.•The maximum thermal capacities of 2.24kJ/K and 2.90kJ/K are obtained for 3mm tpin-fin.•Thermal conductance of 6.95×10-1W/K and 5.69×10-1 are obtained for paraffin wax and n-eicosane.
The present paper covers the comparison of two different configurations (square and circular) pin-fin heat sinks embedded with two different phase change materials (PCMs) namely paraffin wax and n-eicosane having different thermo-physical properties were carried out for passive cooling of electronic devices. The pin-fins, acting as thermal conductivity enhancers (TCEs), of 2mm square and 3mm circular fin thickness of constant volume fraction of 9% are chosen and input heat fluxes from 1.2kW/m2 to 3.2kW/m2 with an increment of 0.4kW/m2 are provided. Two different critical set point temperatures (SPTs) 45°C and 65°C are chosen to explore the thermal performance in terms of enhancement ratios, enhancement in operation time, latent heating phase duration, thermal capacity and conductance. The results show that 3mm diameter of circular pin-fins has the best thermal performance in passive thermal management of electronic devices.
•Two nano-enhanced fatty acids with Tm within building application were developed.•Capric acid and capric–myristic mixture were successfully enhanced by adding nSiO2.•The NEPCM obtained showed high ...thermal conductivity and specific heat capacity.•Both are thermal-stable, ensure long-term performance and behave as Newtonian fluid.•NEPCM are promising available materials to store thermal energy.
Fatty acids are promising organic phase change materials (PCMs) for thermal energy storage (TES) in buildings because of their high storage capacity, non-toxic nature and little subcooling. Their phase change temperatures make them suitable for heating, ventilating and air conditioning (HVAC) applications in the building sector. However, one of their main drawbacks is their poor thermal conductivity which limits their application. In the present study two fatty acids within the building application temperature range, capric acid (CA) and capric–myristic acid (CA–MA) eutectic mixture, were nano-enhanced throughout silicon dioxide nanoparticles (nSiO2) addition (0.5 wt.%, 1.0 wt.% and 1.5 wt.%). Main properties of the nano-enhanced phase change materials (NEPCM) obtained were characterized by means of differential scanning calorimetry (DSC), Hot wire technique, Fourier transformed infrared (FT-IR) spectroscopy, thermogravimetric analyses (TGA), scanning electron microscopy (SEM), and rheological measurements. Furthermore, their long-term performance was evaluated after 2000 cycles by means of cycling stability tests. The NEPCM obtained showed high thermal conductivity and specific heat capacity. Additionally, both are thermally stable within their working temperature range and ensure a long-term performance.
Due to the unique thermal absorption and release capabilities, phase‐change materials (PCMs) are used in various industrial fields, such as photo‐thermal storage and building‐energy saving. In recent ...years, more and more research has been dedicated to applying PCMs to the medical field with substantial progress, opening new avenues for disease treatment and healthcare. The safety and reliability of PCMs may be taken into serious consider for continuous application in the medical field, while the relevant review on the related development is currently lacking. In this work, the methods for enhancing the applicability and reliability of PCMs in the medical field are systematically summarized, including microencapsulation, electrospinning technology, and porous framework encapsulation, which effectively address the issues of liquid leakage. Subsequently, the emerging advances of PCMs in medical healthcare, including medical dressings treatment, drug delivery, cold chain transport, and bio‐bone cement are summarized. By exploring and analyzing the encapsulation methods, principles as well as the emerging advances of PCMs in medical field, the challenges and perspectives promoting the applications are identified, presenting the guidelines for further development.
This work systematically summarizes the encapsulation methods for enhancing the applicability and reliability of phase change materials (PCMs) from the perspective of safety and reliability, as well as the emerging advances of PCMs in medical healthcare, clarifying the challenges and prospects for promoting the applications in the medical field, presenting the guideline for the further development.
Integrating phase change material (PCM) into building envelopes significantly reduces building energy consumption and improves indoor environment. Among different integration techniques, ...macro-encapsulation allows for an efficient, safe and convenient way of using PCM, and its applications have been widely investigated in recent years. However, this study argues that there is a lack of a systematic analysis regarding the thermal performance of macro-encapsulated PCM, particularly for building envelope applications. Also, a number of important issues have seldom been addressed such as material selection and PCM melting processes at a component level, and optimal locations at a system level. Such a research gap remains a barrier to architects and engineers succeeding at making rational decisions during building design stages, thereby achieving the optimal building performance. This paper aims to provide a comprehensive overview of macro-encapsulated PCM and its integration into building envelopes. The discussion mainly includes: definition and material selection for PCM macro-encapsulation, common macro-encapsulation forms and PCM melting processes within these forms, the optimal locations of systems in building envelopes, and thermal performance enhancement for PCM and shells. In addition, the key issues in future studies are discussed. It is hoped that this comprehensive review will contribute to a deeper understanding of the design and application of macro-encapsulated PCM in building envelopes.
•Comprehensive review on macro-encapsulated PCM in building envelopes.•Definition and material selection for PCM macro-encapsulation.•Common macro-encapsulation forms and PCM melting processes within these forms.•Thermal performance enhancement for macro-encapsulated PCM.
The objective of this study is to overcome the leakage and low thermal conductivity problems of paraffin as PCMs (phase change materials) for thermal energy storage by impregnating SEBS/paraffin/HDPE ...FSPCMs (form-stable phase change materials) into metal foam. The form-stable composites were prepared by absorbing paraffin into the network of powder-like styrene-b-(ethylene-co-butylene)-b-styrene (SEBS) triblock copolymer and covering high-density polyethylene (HDPE) on pre-prepared SEBS/paraffin mixture. The composites were characterized by using differential scanning calorimetry (DSC), Scanning electron microscope (SEM), Fourier Transform Infrared Spectrometer (FT-IR), X-Ray Diffraction (XRD) and Hot disk. Paraffin leakage was investigated by accelerated degradation test at 80°C. The melting temperature and latent heat of the composites were determined as 50.56°C and 151.6J/g, respectively. FT-IR results revealed good chemical compatibility among paraffin, SEBS and HDPE. SEM images and XRD test results demonstrated that the paraffin had uniformly dispersed into SEBS. This composite was testified able to keep paraffin from seepage with only 2.39wt% of paraffin loss after 50 thermal cycles test (150h). In addition, the thermal conductivity of SEBS/paraffin/HDPE was 0.272W/mK, which was increased up to 2.142W/mK when copper foam was embedded in the composite.
•SEBS/paraffin/HDPE form stable PCM was prepared using a direct impregnation method.•Microstructure and thermal properties of the composites were examined.•The FSPCMs show nearly no leakage under accelerated degradation thermal tests.•The FSPCMs are able to impregnate into metal foam to enhance heat transfer.
Increased energy consumption in buildings is a worldwide issue. This research is concerned with the implementation of a phase change material for thermal storage. This concept has gained great ...attention as a solution to reduce energy consumption in buildings. Beeswax, which is a phase change material with a high thermal capacity, is investigated in this research. This paper is intended to measure and analyze the thermal properties of beeswax/graphene as a phase change material. The melting temperature, thermal capacity and latent heat were determined using differential scanning calorimetry (DSC), and the thermal conductivity was investigated using a thermal conductivity measurement apparatus. To discover the change in the physical properties due to the effect of nanoparticles, the viscosity of the material was investigated as well. Based on the result from the DSC, the latent heat of 0.3wt% beeswax/graphene increased by 22.5%. The thermal conductivity of 0.3wt% beeswax/graphene was 2.8W/mK. The existence of graphene nanoplatelets enhanced both the latent heat and thermal conductivity of the beeswax. Therefore, based on this result, beeswax/graphene is concluded to have the potential to reduce energy consumption in buildings.
•Nanocomposite phase change materials were prepared and characterized.•Larger specific surface area is more efficient to enhance specific heat.•Columnar structure is more efficient to enhance thermal ...conductivity.•Thermal conductivity enhancement is the key.•Single walled carbon nanotube is the optimal nanomaterial additive.
To enhance the performance of high temperature salt phase change material, four kinds of carbon nanomaterials with different microstructures were mixed into binary carbonate eutectic salts to prepare carbonate salt/nanomaterial composite phase change material. The microstructures of the nanomaterial and composite phase change material were characterized by scanning electron microscope. The thermal properties such as melting point, melting enthalpy, specific heat, thermal conductivity and total thermal energy storage capacity were characterized. The results show that the nanomaterial microstructure has great effects on composite phase change material thermal properties. The sheet structure Graphene is the best additive to enhance specific heat, which could be enhanced up to 18.57%. The single walled carbon nanotube with columnar structure is the best additive to enhance thermal conductivity, which could be enhanced up to 56.98%. Melting point increases but melting enthalpy decreases with nanomaterial specific surface area increase. Although the additives decrease the melting enthalpy of composite phase change material, they also enhance the specific heat. As a combined result, the additives have little effects on thermal energy storage capacity. So, for phase change material performance enhancement, more emphasis should be placed on thermal conductivity enhancement and single walled carbon nanotube is the optimal nanomaterial additive.
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