Implementation Of Phase Change Materials Research Articles

An Overview of Phase Change Materials and Their Applications in Pavement

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

Enhancing the thermal performance of polyethylene glycol phase change material with carbon-based fillers

New implementation of phase change materials (PCMs), such as Polyethylene Glycols (PEGs), can alleviate the overconsumption of natural resources and can also be applied in solar-thermal energy conversion applications due to their distinctive semi-crystalline structure. To further enhance the thermal properties of PCMs, carbon-based nanomaterials such as graphene nanoplatelets (GNPs) and milled carbon fibre (MCF) can be incorporated to fabricate PEG-based composites due to their high thermal conductivity. One of the possible drawbacks of the addition of carbon-based fillers is their aggregation at high loadings, leading to a possible reduction in the latent heat of PCM composites. Hence, this study explored the most appropriate loading level (5 wt.%) of carbon-based fillers with pristine PEGs to achieve optimal thermal performance. Specifically, PEG-based composites were synthesised with three fillers (GNPs, graphite and MCF) via a temperature-assisted ultrasonication method and rapid solidification. Then, Raman Spectroscopy was used to quantify the dispersion of fillers among the PEG matrices. The results showed that despite a 32.6 % reduction in enthalpy of fusion to 155.5 J g–1, the addition of 15 wt.% of MCF increased the thermal conductivity up to 0.67 W m–1 K–1, which was approximately 2.5 times higher than that of pristine PEG. Moreover, explanations were provided on the possible heat transfer mechanisms in different types of carbon-based fillers. PEG/MCF PCMs displayed good properties on latent heat, thermal conductivity, aggregation prohibition, volumetric heat capacity, phase change temperature and thermal stability, while PEG/graphite composites exhibited excellent performance on thermal diffusivity, phase change (melting) temperature, specific heat capacity and cyclability.

Novel indicators to evaluate PCM performance under different ventilation strategies by considering the impact of climate change

Due to climate change, the cooling energy demand in the building sector is projected to increase significantly. According to International Energy Agency, for a sustainable future, energy-efficient technology should be implemented in buildings. The potential of Phase change materials (PCM) for reducing building energy consumption has been widely acknowledged by researchers. However, the selection of appropriate PCM and its latent heat exploitation is crucial when PCM is integrated into the building envelope. This research evaluates the implementation of PCM for building cooling energy savings (CES) with climate change in thirty-nine cities located in 13 different zones of the future Koppen-Geiger climate map. Novel performance indicators, energy charging, and discharging coefficients are presented, to evaluate the PCM performance based on the exact latent heat exploitation. A range of PCMs (PCM 18–32) were assessed by coupling PCM with free night ventilation and changeover ventilation using the hybrid downscaled weather files for 2095. The results showed that the optimum PCM varied from PCM27 to PCM30 resulting in substantial CES (1214 kWh-7240 kWh) in all zones except Cfb, Dfa, and Dfb under the indoor HVAC controlled conditions. In natural ventilation conditions, combining PCM with free night ventilation increased CES up to 2490 kWh compared to night ventilation alone, while combining PCM with changeover ventilation, reduced energy consumption by up to 2772 kWh compared to changeover ventilation alone. Overall, free night ventilation with PCM improved the CES by up to a maximum of 35% while changeover ventilation in combination with PCM further increased the CES by up to 96% and appeared to be the best strategy for maximizing the CES in all climate zones.

A novel liquid air energy storage system integrated with a cascaded latent heat cold thermal energy storage

Liquid air energy storage system (LAES) is a promising Carnot battery's configuration that includes thermal energy storage systems to thermally connect the charge and discharge phases. Among them, the high grade cold storage (HGCS) is of paramount importance due to the waste cold recovery of the liquid air regasification process. As of now, most of the literature studies on LAES designed to store the cryogenic energy using sensible heat material and only few works (including one recently carried out by the authors) proposed the implementation of phase change materials (PCMs) as alternative promising solution. This paper goes a step further numerically investigating a novel configuration of the HGCS system utilizing a cascade of multiple PCMs in place of the single PCM HGCS. By enhancing the thermal buffer effect typical of PCM media, the cascaded HGCS augments both the capacity ratio of the charge phase (0.87 vs 0.81) and the utilization factor of the discharge phase (0.87% vs 0.80%). As a result, the novel LAES system based on cascaded PCMs is capable to achieve a liquefaction specific consumption of 0.27 kWhe/kgLA, increasing thus the liquefaction performance of the single PCM HGCS by 6%.

A novel liquid-based battery thermal management system coupling with phase change material and thermoelectric cooling

The present study experimentally investigates a novel type of battery thermal management system that works based on water cooling and thermoelectric cooling (Peltier effect). In the current proposed system, water cooling is targeted by a number of thermoelectric coolers (TEC) and the temperature of the hot side of the TECs is controlled by the RT35 phase change material (PCM). To conduct a comparison, the results are compared with the case in which the hot side of the TECs' temperature is managed using forced convection (FC) driven by fans. Moreover, the variations of TECs number, assuming constant applied power are examined. Results indicated that the thermoelectric module is considerably effective on controlling the battery pack temperature. Such that, after 90 min of the initiation of the experiment, the cases of 2TEC which benefit from FC and PCM reduce the battery pack temperature 11.3 °C and 17.75 °C respectively in comparison with the system without a cooling device. The obtained results show that the implementation of PCM in comparison with FC is more effective on controlling the temperature of the battery pack simulator (BPS). In other words, the temperatures of the battery pack for the PCM cases are 4.1 °C to 12.64 °C lower than that of the corresponding FC cases. Results also indicated that the coefficient of performance of the system is proportionally related to the number of the cooling modules and is inversely affected when the applied power to the thermoelectric module rises. Results also revealed that among the cases, in 14 conditions the temperature of the battery pack lowers to a value <40°C; 9 cases of which contains PCM and 5 systems benefits from FC cooling. The best case among the studied ones is 3TEC/P2/PCM which suggests maximum battery temperature of 37.8 °C, 12.4 W power consumption and 3.23 coefficient of performance.

Mitigation of firefighters’ skin burn injuries utilizing auxiliary measures

The improvement in the thermal resistance of firefighter’s outer garments has been traditionally achieved with the implementation of phase change materials or aerogel as an added protective measure. This study proposes supplementary novel cost-effective measures to enhance the thermal resistance of conventional firefighter outer garments. The proposed measures consist of auxiliary protective layers of meta-aramid fabric of a plain weave and a honeycomb structure. A custom built vertically oriented bench-scale apparatus was used to simulate extreme to life-threatening fire environments characterized in terms of an incident radiative flux of 84 kW/m2 and 126 kW/m2. The fluctuations in experimental heat flux density were treated by employing a Gaussian empirical model. The heat dissipation rate within the skin layers was predicted with a numerical model based on finite element methodology. The skin burns were classified with Henrique’s integral. The conventional outer garment when exposed to 84 kW/m2 and 126 kW/m2 resulted in a superficial second and third-degree burn. The auxiliary layers, in conjunction with the outer garment, mitigated second and third-degree burns. The meta-aramid fabric of a plain weave exhibited better thermal resistance than the honeycomb structure layer. The proposed measures reduced the epidermis temperature by 32%. An inner garment made of meta-aramid fabric is recommended to be worn concurrently with an outer protective suit for severe fire incidents due to its relative ease of use. Honeycomb structure layers are not recommended due to their weak structure and restriction in mobility.

Implementation of phase change material for cooling load reduction: a case study for Cairo, Egypt

Integrating a phase change material (PCM) into building envelopes can reduce energy needs in the built environment, and the consequent greenhouse emissions. This research examines the impact of PCM integrated into a traditional wall in Egypt on peak and average cooling energy consumption. A MATLAB code based on the finite volume technique using the Crank-Nicolson method for discretization is implemented. Several benchmark cases and experimental results validate the code. The time-dependent boundary conditions of the cases examined were based on the irradiance and ambient temperatures measured in Cairo, Egypt. Simulations are performed on eight different PCMs, using their real published DSC curve. The study aims to investigate the performance of each PCM at different positions, thicknesses, and wall orientations. The calculations revealed that using the proper PCM type and the proper position could decrease the average by 38.14%, Also the peak heat flux could be decreased by 58.53%.

A critical assessment of the implementation of phase change materials in the VCC of refrigerator

The ultimate heat storage system is an alternative way of improving the heat exchange in the home refrigerator. This research is a systematic analysis of the studies that are being performed with its advantages and limitations. Comments of the researcher on potential improvements in the current work to enhance efficiency are also checked. Key parameters influencing system performance and key issues related to effective system integration are discussed here. PCM integration with the standard setup is restricted by the use of low-temperature PCMs, which is why PCM analysis with Nano-particle additives can be performed. Most experiments are limited to a hot wall form only, the investigation of a PCM application for another form of the condenser is subject to further work. Besides, a combination of two thermal enhancement methods, such as LSHX and PCM, can be used to test the performance.

Nonvolatile Plasmonics Based on Optically Reprogrammable Phase Change Materials

Here, a new platform for a realization of novel nonvolatile optical switching devices was proposed that takes an advantage of high field confinement provided by plasmonics and multi-state programming capabilities of chalcogenide phase change materials. A high reduction in the overall energy consumption consists of a high field enhancement provided by plasmonic that allow to lower the switching energies and implementation of phase change materials that allow to operate under a zero-static power consumption. A combination of plasmonics and phase change materials provide additionally an essential improvement in terms of a switching time, attenuation contrast and possibility to perform a phase shift with the wide bandgap phase change materials. In most of the all-optical switching photonic devices, a switching mechanism is realized optically through heating of phase change materials. Here, two stage heating process is proposed that is based on the absorption of light by phase change materials itself, and a heat transfer from the metal stripe under an absorption of light by a metal. Thus, compared to any other previously presented optical switches, even a wide bandgap phase change materials that show zero absorption of light can be implemented in the proposed structure. The proposed plasmonic waveguide arrangement is extremely sensitive to any changes of the phase change material properties, thus, even a minor change of temperature provides an essential change in the transmitted light.

Electrical power consumption reduction in the bitcoin mining process using phase change material

In this paper, the idea of applying phase change materials (PCMs) as a method of energy use reduction in bitcoin mining will be investigated. The possible applications discussed include the implementation of PCMs in the mining equipment itself, the integration of PCMs into the mining warehouse envelope, and the use of PCMs in air conditioning systems. These applications aim to decrease energy requirements for warehouse climate control systems by decreasing their cooling load, and by increasing the efficiency of the miners by keeping them at a cooler operating temperature. This reduction in energy usage will help reduce bitcoin’s carbon footprint produced by fossil fuels electricity production.

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

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

An Explicit Finite Element Method for Thermal Simulations of Buildings with Phase Change Materials

The thermal performance of building envelopes is essential for building thermal comfort and the reduction of building energy requirements. Phase change materials (PCMs) implemented in building envelopes can improve thermal performance. An explicit finite element method (ex-FEM) has been developed based on a previous study to investigate the heat transfer performance through building walls with installed PCMs. For verification, we introduce an electrical circuit analogy (ECA) method. For model validation, at first, COMSOL is used. For comparison, data were collected from experiments using a small hotbox, part of the sides are covered by PCMs with different configurations. This work shows how the ex-FEM model can predict the wall’s temperature profile with and without incorporated PCM. With the implementation of PCMs, the work problematizes unpredictable influences for modeling. In addition, the study introduces results from simulations of sequencing of PCM layers in wall construction.

Parametric study of solid-solid translucent phase change materials in building windows

Thermal energy storage and solar radiation management are crucial to improve the sustainability and energy efficiency of buildings. Compared with the implementation of phase change materials (PCMs) in opaque components, the energy saving potential of incorporating PCMs in transparent glazing windows is much less studied and not well understood. Here we present a comprehensive parametric study of novel PCM windows for building energy saving with a focus on optimizing and quantitatively distinguishing the contributions from the optical and thermal properties of the PCM, which is particularly useful for the design of solid-solid PCM windows. We investigate a reference commercial office building using EnergyPlus by developing an equivalent model of our PCM window that is compatible with EnergyPlus’s modeling capabilities. Compared with a clear-clear double-pane window, the integration of 3 mm solid-solid PCMs with optimal properties in warm, mixed, and cold climates can respectively save up to 17.2%, 14.0%, and 5.8% energy for the HVAC (heating, ventilation, and air conditioning) system, and 9.4%, 6.7%, and 3.2% energy for the whole building. We also demonstrate that these energy savings are most sensitive to the solar absorptance of PCMs for all three climates. The optimal transition temperature varies with climate and is related to the climate and solar radiation heat gain. Other issues are also briefly discussed, such as hysteresis, window orientations, and the effect of interior lighting. Although the optimal PCM windows show energy saving performance comparable with low-emissivity windows, the PCM windows provide a unique advantage in terms of shifting HVAC loads which can provide benefits to the electrical grid.

Phase Change Material Integration in Building Envelopes in Different Building Types and Climates: Modeling the Benefits of Active and Passive Strategies

Among the adaptive solutions, phase change material (PCM) technology is one of the most developed, thanks to its capability to mitigate the effects of air temperature fluctuations using thermal energy storage (TES). PCMs belong to the category of passive systems that operate on heat modulation, thanks to latent heat storage (LHS) that can lead to a reduction of heating ventilation air conditioning (HVAC) consumption in traditional buildings and to an improvement of indoor thermal comfort in buildings devoid of HVAC systems. The aim of this work is to numerically analyze and compare the benefits of the implementation of PCMs on the building envelope in both active and passive strategies. To generalize the results, two different EnergyPlus calibrated reference models—the small office and the midrise apartment—were considered, and 25 different European cities in different climatic zones were selected. For these analyses, a PCM plasterboard with a 23 °C melting point was considered in four different thicknesses—12.5, 25, 37.5, and 50 mm. The results obtained highlighted a strong logarithmic correlation between PCM thickness and energy reduction in all the climatic zones, with higher benefits in office buildings and in warmer climates for both strategies.

Implementation of phase change materials for thermal regulation of photovoltaic thermal systems: Comprehensive analysis of design approaches

This work was focused on the investigation of various photovoltaic thermal (PVT) solar collector designs incorporating phase change materials (PVT-PCM systems) as suitable material for thermal management. In general, the PCM materials utilized in such systems were analyzed along with a discussion regarding the main thermal properties. The experimental works were covered from existing literature and related to PVT-PCM systems in various climates. The results revealed the importance of a PVT-PCM collector design concerning the overall efficiency improvement of systems. Depending on the specific design, as well as on the specific working fluid (water, air, or nanofluids), the electrical efficiency improvement was usually less than 20%, while the improvement in thermal efficiency was usually up to 70%. The electrical efficiency improvement is especially sensitive to the specific PVT-PCM collector design. The economy of the PVT-PCM system was not addressed well in the existing literature as well as its environmental evaluation. The usual payback time of the PTV-PCM systems ranged from 4 to 15 years. The conducted review indicated the necessity for more intense research investigations related to improvements in collector designs (tube geometry and layout, novel absorbers, optimization of the PCM layer) and for an integral assessment of PVT-PCM collector designs, considering performance, economic and environmental evaluations.

A novel solar-geothermal system integrated with earth–to–air heat exchanger and solar air heater with phase change material—numerical modelling, experimental calibration and parametrical analysis

In order to compensate drawbacks of traditional earth–to–air heat exchanger (EAHE) system, such as the unstable outlet air temperature, the overheating and the limited operation period, a novel coupled system systematically integrating an EAHE and a solar air heater (SAH) with phase change material (PCM), was proposed in this study. The complementary between geothermal and solar energy is exploited and served for building energy savings. On-site experimental testing and enthalpy-based numerical modelling using the control volume method were conducted for thermal and energy performances prediction. Systematic and parametrical analyses have been conducted using the developed mathematical model to investigate the effects of critical parameters on the thermal and energy performances. Our findings illustrate that the implementation of PCM can effectively stabilize the outlet air temperature for nearly 4.5 h and prolong the working period to 24 h. Due to the heat transfer enhancement, the increase of the airflow rate can significantly increase the system heating capacity, whereas the outlet air temperature is decreased with a maximum magnitude of 5.3 °C. Furthermore, the diurnal thermal performance of the system is highly dependent on the phase change temperature, whereas the time-duration of the effective operation is highly dependent on the PCM latent heat. Moreover, the system nocturnal thermal behavior can be improved with the increase of the PCM thermal conductivity, whereas a saturated improvement can be noticed when the PCM thermal conductivity is 1.0 W/(m·K). This study proposes a complementary geothermal and solar energy system, together with phase change material for the performance stability improvement, which are important for the promotion of green buildings with energy-efficient utilization of geothermal and solar energy.

Control of room temperature fluctuations in the building by incorporating PCM in the roof

The energy demand for maintaining the required thermal comfort in the building is always an increasing trend. The use of an air conditioner in the building for providing thermal comfort consumes more energy, and it leads to negative environmental impacts. Thermal energy storage (TES) systems are essential to reduce energy consumption in the building. The phase change material (PCM)-based TES in the building has attracted attention in the recent years. In the PCM-based TES system, the heat energy gained during daytime is absorbed by the PCM and the stored energy is released during the night time. The objective of the work is to control the room temperature fluctuations by incorporating PCM in the building roof. The experiments are conducted in two identical model buildings: one is constructed with the implementation of PCM, and another one is constructed without the implementation of PCM in the building roof. It has been observed that the temperature fluctuations in the building are reduced by the use of PCM in the roof. The average peak temperature rise is reduced about 1–2 °C in the building with PCM incorporation in the roof, and thus, the energy required for maintaining the thermal comfort of the room is greatly reduced.

ANÁLISIS DE CONSUMOS ENERGÉTICOS DE AISLANTES TRADICIONALES Y MATERIALES DE CAMBIO DE FASE APLICADOS A CONTENEDORES MARÍTIMOS PARA DESPLIEGUES MILITARES

Standardized out-of-service maritime containers can be used as occupation solutions in military deployments. This type of constructions generally experience strong fluctuations of indoor temperatures due to the low thermal mass of its envelope. The implementation of Phase Change Materials (PCM) in the enclosure is a solution to cushion thermal changes and reduce energy demands. In this work, several insulations with PCM in maritime containers are compared as a passive solution to achieve energy savings under different climatic conditions. The results show the capacity of the PCM technology, which must be selected based on the climate where the module is located, in order to reduce both heating and cooling demands. Keywords: maritime containers, insulating, thermal simulation, EnergyPlus, energy savings

“Simulation of Double Pipe Heat Exchanger with Implementation of PCM”

In the present time several techniques have been developed in managing and storing thermal energy. Use of Thermal energy storage systems (TES) are one of the solutions for this issue. Hence in the present work, phase change materials (PCM) are used for storing thermal energy. D-mannitol and Hydroquinone are the two PCM materials used in double pipe heat exchanger and simulations are carried out analytically on ANSYS. Study of temperature variation is done with respect to time and values are calculated for time, t = 200, 500, 2200 and 4200 seconds. The results also include contour plots and numerical values for mass fraction for each of the case. The result shows, that with increase in the time step, the temperature gradually increases for both the cases of PCM materials.

Thermal transport properties at interface of fatty acid esters enhanced with carbon-based nanoadditives

There has been growing interest in the development and use of sustainable, bio-based phase change materials (PCMs), as an alternative to conventional paraffinic PCMs. Among possible choices, two fatty acid esters, i.e., methyl palmitate and methyl 9,10-dihydroxystearate, are investigated in this study. The physical properties of these two bio-based PCMs are first characterized using the molecular dynamics method. Upon validating the results with the experimental test data, the reverse non-equilibrium molecular dynamics (RNEMD) method is employed to evaluate the thermal performance of these two PCMs in both pristine and enhanced conditions. The interplay between the molecular structure and thermal properties is then determined using a radial distribution function analysis. To address the issue of low thermal conductivity of these two PCMs, the possibility of enhancing them with carbon-based nanoaddivities, such as graphene, is investigated. The interface between the PCM matrix and the graphene filler is modeled at nanoscale and the interfacial thermal conductance is characterized using the RNEMD simulations. A separate set of vibration power spectra analyses are conducted to shed light on the thermal energy transfer mechanisms across the interface of bio-based PCMs and carbon-based nanoadditives. The outcome of this study is expected to transform the design and implementation of PCMs for sustainable energy storage technologies.