Design Of Phase Change Materials Research Articles

A study on novel dual-functional photothermal material for high-efficient solar energy harvesting and storage

The solar-heat storage efficiency of devices based on phase change materials (PCMs) is limited due to the light absorption and internal heat transfer within the PCMs, unclear thermal conductivity-enhancement mechanism within nanocomposite PCMs, and uncontrollable photothermal-interface modulation. Therefore, a novel controllable strategy was proposed in this study to fabricate dual-functional photothermal storage three-dimensional (3D) phase change blocks (PCBs) with higher thermal conductivity (27.98 W/m·K) and spectral absorption (98.03%) compared to those of most previously reported PCM-based devices. The as-synthesized PCBs contained millimeter-sized graphite plates with horizontal Van der Waals bonds and oriented micro/nanoscale graphite nanosheets. The structural properties of thin PCM layers between the PCB sheets have synergistically reduced the internal interfacial thermal resistance of the PCBs. Laser-controllable induction was used to fabricate integrated biomimetic-forest 3D optical absorbers on the high thermal conductivity interface of the PCBs, which significantly reduced the thermal resistance of the optical-thermal interface. The resulting 3D-PCBs, integrated with thermoelectric generators, powered portable electronic devices, expanding the applications of traditional PCM heat-storage devices. Therefore, this study will guide the future design of high-performance solar-thermal storage PCMs with a wide range of practical applications.

Transient analysis of PCM discharging in a rotary triplex tube with wave-shaped fins

Phase change material (PCM) based thermal storage units have attracted attention in energy storage technology. To improve its effectiveness, researchers have introduced various techniques. In this study, a novel rotary triplex tube with sinusoidal wave-shaped fin design is proposed as a PCM based thermal storage unit, and its performance is compared with a conventional straight fin design. A two-dimensional numerical model is developed for the transient analysis of discharging process of PCM. The discharging process is modelled using enthalpy porosity technique. The validation of the model is done against the experimental result from the literature. The discharging process of PCM is analyzed at different rotational speeds. Thermal performance and fluid flow dynamics are evaluated by analyzing the molten portion, temperature, and velocity variation. The result showed that an increase in rotational speed led to an increase in the discharging rate of the PCM. When there is no rotation or slow rotation (0.05 and 0.1 RPM), the discharging is faster in the unit with straight fins compared to the unit with wave-shaped fins. However, at higher rotational speeds (0.2, 0.3 and 0.4 RPM), discharging is faster in the unit with wave-shaped fins. Overall, this study provides insights into the design and performance of PCM based thermal storage unit and suggests the use of wave-shaped fins for higher rotational speeds to enhance the discharging rate of PCM.

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 Thermal Performance of Phase Change Material Embedded Solar Air Heater Employing Impinging Stable Air Jet Array Presenting High Power and Energy Density

Abstract This experimental thermal performance investigation presents that the hot air at a significantly high temperature, and simultaneously at high power density and energy density of phase change material (PCM) can be obtained utilizing a novel design of PCM embedded solar air heater employing impinging stable air jet array. Investigation is carried out following two main objectives, i.e., to obtain (i) instant and (ii) long thermal backups. In the reported design configuration, impinging stable air jets on absorber plate are obtained by reducing the flow path of expelled air from upstream air jets that increased the heat transfer rate to air and consequently instant thermal backup. Although, the use of wavy PCM unit provides instant and long thermal backup by increasing heat transfer area that augments the heat transfer to air and the collection of solar radiations, respectively. Moreover, the present study is extended as follows, (i) the use of shutter on glass cover to increase thermal performance during nocturnal hours, (ii) charging of PCM till the maximum solar radiation hours and use of the stored energy during nocturnal hours, (iii) thermal performance analysis to reveal instant thermal backup, (iv) thermal performance investigation during variable weather conditions, and (v) thermal performance investigation for low ambient air temperature. The obtained results revealed that for the unit collector area, significant thermal backup of about 6 h at a temperature rise of ≥5 °C can be obtained by utilizing the above-mentioned provisions in this research.

Numerical investigation of the air conditioning system performance assisted with energy storage of capsulated concave/convex phase change material

One of the highest energy drains in homes and businesses is the air conditioning (AC) system. Thus, any slight improvement in the AC system performance can result in considerable energy savings. This numerical study aims to boost the AC performance in hot environments via thermal energy storage. This is accomplished by directly cooling the AC condenser using capsulated phase change materials (PCM). The PCM is capsulated in a new design of concave/convex (CX) plates to reduce the lengthy PCM solidification time and also enhance the AC performance. The PCM is solidified during a relatively low nighttime temperature and then cools the AC condenser during daytime operation. The proposed encapsulated PCM design's impact on the AC performance is assessed and compared to those of used flat plates. Using ANSYS Fluent, a mathematical equations model is developed and solved and then validated via an experimental test rig of the PCM flat plates. The effects of varying the size and number of concave/convex configurations are investigated. It is found that concave/convex PCM plates greatly minimize the solidification/melting periods compared to flat plates, making them effective in AC system daily work. Rising the CX diameter and numbers enhances the PCM melting and solidification rates and decreases the air outlet temperature. Moreover, the saved percentage of the power rises with the ambient temperature and airflow rate rising. Further, the AC power usage by adopting PCM concave/convex plates is saved by a maximum value of about 16 % and 7.5 % when working for 120 and 300 min, respectively.

Shape-stable erythritol composite phase change materials with controlled latent heat release for spatiotemporally thermal energy utilization

Phase change materials (PCMs) have been extensively concerned recently as suitable medium for thermal energy storage due to their absorbing or releasing a large amount of latent heat in the phase change process. However, traditional PCMs usually crystallize spontaneously to release their latent heat in the cooling process, which greatly limits their practical application in thermal energy long-term storage and controllable release. Herein, we designed and synthesized a shape-stable erythritol (ERY)-based composite PCM with attractive performance of latent heat controlled storage and release using a facile aqueous fabrication route. In this composite, calcium ions cross-linked with sodium alginate is introduced to construct strong hydrogen bonding with ERY to increase the activation energy barrier for stabilizing supercooling, thus realizing long-term latent heat stored in supercooling state. The supercooled ERY composite can be maintained at room temperature for 50 days and subsequently controllably releases latent heat by thermal or mechanical trigger method. Meanwhile, the ERY composite exhibits excellent shape stability without any leakage over the phase change temperature. In addition, the crystallization enthalpy can reach 181.2 J/g, which can be maintained even after 80 thermal cycles, showing superior thermal energy storage capacity and repeatability. The crystallization kinetics study reveals that the crystallization mode of the ERY composite is three-dimensional growth spherical diffusion. This work provides an important strategy for the design and synthesis of shape-stable PCMs with controllable latent heat storage and release performance, which is of great prospect for the development of spatiotemporally thermal energy storage technology.

Spatiotemporal phase change materials for thermal energy long-term storage and controllable release

Phase change materials (PCMs) have attracted much attention in the field of solar thermal utilization recently, due to their outstanding thermal energy storage performance. However, PCMs usually release their stored latent heat spontaneously as the temperature below the phase transition temperature, rendering thermal energy storage and release uncontrollable, thus hindering their practical application in time and space. Herein, we developed erythritol/sodium carboxymethylcellulose/tetrasodium ethylenediaminetetraacetate (ERY/CMC/EDTA-4Na) composite PCMs with novel spatiotemporal thermal energy storage properties, defined as spatiotemporal PCMs (STPCMs), which exhibit the capacity of thermal energy long-term storage and controllable release. Our results show that the composite PCMs are unable to lose latent heat due to spontaneous crystallization during cooling, but can controllably release thermal energy through cold crystallization during reheating. The cold-crystallization temperature and enthalpy of composite PCMs can be adjusted by proportional addition of EDTA-4Na to the composite. When the mass fractions of CMC and EDTA-4Na are both 10%, the composite PCMs can exhibit the optical cold-crystallization temperature of 51.7 °C and enthalpy of 178.1 J/g. The supercooled composite PCMs without latent heat release can be maintained at room temperature (10–25 °C) for up to more than two months, and subsequently the stored latent heat can be controllably released by means of thermal triggering or heterogeneous nucleation. Our findings provide novel insights into the design and construction of new PCMs with spatiotemporal performance of thermal energy long-term storage and controllable release, and consequently open a new door for the development of advanced solar thermal utilization techniques on the basis of STPCMs.

One-way freezing method to construct MWCNTs/BC framework in melamine foam for composite phase change materials applied in thermal management and energy conversion

Latent heat storage (LHS) possesses a great energy storage density, which can reduce the pressure of imbalance between energy consumption and supply. As a commonly used medium for LHS, solid-liquid phase change materials (PCMs) have received growing attentions. However, some inherent defects such as strong rigidity, easy leakage and low thermal conductivity limit further their applications. In this work, a flexible porous framework was constructed using the melamine foam (MF) as the template and the multi-walled carbon nanotubes (MWCNTs)/bacterial cellulose (BC) hybrids as the fillers, then the PEG was encapsulated to fabricate the composite PCMs. Herein, we investigated the microstructure and flexibility of the three-dimensional (3D) porous matrix, and the microscopic morphology, encapsulation capacity, heat storage/release behavior, temperature regulation ability and light to thermal conversion performance of the composite PCMs were also studied. Experimental results suggested that the prepared 3D scaffold had ultra-light characteristics and outstanding resilience performance. The involvement of BC increased the specific surface area of the MF skeleton, thus its adsorption to PEG was more stable. The thermal energy storage efficiency of composite PCMs was as high as 91.5%. Meanwhile, the composite PCMs performed sensitive thermal response behavior and could generate shape memory driven by heat. Furthermore, it also showed excellent light to thermal conversion performance with a corresponding conversion efficiency of 87.9%. This study provides a new strategy for the design and development of advanced composite PCMs, which is expected to expand the applications of PCMs in heat storage, energy conversion, solar energy utilization, and infrared stealth of military targets.Graphical abstract

Ex‐Ante Optimal Design of Sustainable Phase Change Materials for Latent Heat Storage

AbstractEnergy consumption for residential heating can be reduced using new insulation solutions in the form of phase change materials (PCMs) integrated within the building structure. This work proposes a framework for the optimal design of PCMs considering operational as well as sustainability aspects at the early stages of the material development process. The proposed framework applies computer‐aided molecular design tools and considers a practical simulation model to calculate the functional performance of the PCM, as well as a variety of constraints to impose desirable bounds on the material thermophysical properties and its impact on environment and safety.

Periodic energy transmission and regulation of photovoltaic-phase change material-thermoelectric coupled system under space conditions

Phase change material (PCM) as highly efficient temperature control material has been used in photovoltaic-thermoelectric (PV-TE) coupling system to achieve higher power generation efficiency. The periodic energy balance and PCM regeneration are the key factors that affect the temperature control effect and system total performance. In present paper, a numerical model for space PV-PCM-TE system was established with the composite of paraffin and aluminum foam as PCM. Firstly, the impact of periodic energy imbalance on PCM regeneration characteristics and system overall performance was investigated under space conditions. Then, to regulate the periodic energy transmission of the coupling system, a global structural parameters optimization was performed, and the optimal parameter combination was derived and validated, where porosity of aluminum foam, thickness of PCM layer, thermal concentration factor, length of TE legs, and surface area ratio are 0.94, 4.08 mm, 25.83, 1.09 mm and 1.80, respectively. The validation results show that after optimization, the periodic energy balance and PCM full utilization and regeneration can be achieved. The average total efficiency of optimal case is 30.72%, which is a little lower than that with the surface area ratio of 7.0 (31.77%), but the average power density is 49.64% higher. The present work validates that periodic energy balance design is important for space PV-PCM-TE system and the global parameter optimization method is an effective optimization method, which is significant for the design and optimization of PCM based temperature control system.

Impact of placement and design of phase change materials in thermally activated buildings

Phase change materials (PCMs) and thermally activated building systems (TABSs) are two candidate technologies for reducing the energy consumption of modern buildings due to their favorable thermal storage features. However, the existing relevant studies do not specify the optimal integration schemes of PCMs when used in radiant cooling systems. Hence, this paper reports the first attempt to parametrically optimize the PCM-TABS system integration, considering typical open office space in the hot and dry climate zone of Cairo, Egypt. Using dynamic system simulations, four system configurations are examined, regarding the relative positions of the activated slab and Bio-PCM layer (ceiling or floor), and compared to active ceiling or floor systems (without PCMs). The results demonstrate the feasibility and favorableness of using PCMs in TABS, with energy and cost saving up to 18.80 and 19.78 %, respectively. The largest cost savings are achieved when PCMs are incorporated into the radiant ceiling, with a melting temperature of 22.0 °C and thickness of 6.0 cm. Energy savings also increase as the volume of PCMs increases, with melting temperatures closer to the building's setpoint. The percentage of comfortable hours decreases slightly from ~100 % to >95.5 % when using some PCM designs due to their thermal inertia, but PCMs result in generally lower variations of indoor thermal comfort. By mapping the performance of such system configurations, the study can be valuable for researchers and practitioners alike to determine the optimal integration scheme of PCMs in radiant cooling systems.

Aerogels Meet Phase Change Materials: Fundamentals, Advances, and Beyond.

Benefiting from the inherent properties of ultralight weight, ultrahigh porosity, ultrahigh specific surface area, adjustable thermal/electrical conductivities, and mechanical flexibility, aerogels are considered ideal supporting alternatives to efficiently encapsulate phase change materials (PCMs) and rationalize phase transformation behaviors. The marriage of versatile aerogels and PCMs is a milestone in pioneering advanced multifunctional composite PCMs. Emerging aerogel-based composite PCMs with high energy storage density are accepted as a cutting-edge thermal energy storage (TES) concept, enabling advanced functionality of PCMs. Considering the lack of a timely and comprehensive review on aerogel-based composite PCMs, herein, we systematically retrospect the state-of-the-art advances of versatile aerogels for high-performance and multifunctional composite PCMs, with particular emphasis on advanced multiple functions, such as acoustic-thermal and solar-thermal-electricity energy conversion strategies, mechanical flexibility, flame retardancy, shape memory, intelligent grippers, and thermal infrared stealth. Emphasis is also given to the versatile roles of different aerogels in composite PCMs and the relationships between their architectures and thermophysical properties. This review also showcases the discovery of an interdisciplinary research field combining aerogels and 3D printing technology, which will contribute to pioneering cutting-edge PCMs. This review aims to arouse wider research interests among interdisciplinary fields and provide insightful guidance for the rational design of advanced multifunctional aerogel-based composite PCMs, thus facilitating the significant breakthroughs in both fundamental research and commercial applications.

Sodium alginate and Chitosan aided design of form-stable Polyrotaxane based phase change materials with ultra-high latent heat

We prepared a series of highly porous Polyrotaxane/sodium alginate, and Polyrotaxane/Chitosan foam alloys according to a sustainable pathway by using water as the only solvent. The foam alloys were further used as supporter materials for poly (ethylene glycol) (PEG) encapsulation, to fabricate shape-stable bio-based phase change materials (PCMs). The pore morphology and the internal interface between PEG and foam alloys were characterized by scanning electron microscope (SEM). Due to the good compatibility between foam alloys and PEG, the PCM performed perfect anti-leakage properties. The introduction of sodium alginate or Chitosan ensures the shape stability of the PCMs during the phase transition. The PCMs performed good cycle stability and showed ultra-high latent heat (171.6 J g−1–189.5 J g−1). Finally, we compared the typical indicators of this work with those reported in the literature, and the comparison highlighted that the present PCMs have the significant advantages: high melting enthalpy, convenient preparation and outstanding sustainability. Notably, the work provided a sustainable idea for the design of anti-leakage and shape-stable PEG-based PCMs.

Strategic design of PCM integrated burnt clay bricks: Potential for cost-cutting measures for air conditioning and carbon dioxide extenuation

Globally, the energy demand of the building sector has increased intensely. The use of air conditioning in buildings for thermal comfort consumes a large percentage of this energy. The significant worldwide energy demand stresses the importance of net-zero or green buildings for a sustainable future. The present work investigates the air-conditioning cost-saving potential of the duplex house designed with various phase change materials (PCMs) incorporated burnt clay bricks. Five PCMs were selected, including three organic mixture PCMs (OM18, OM21, and OM29) and two form-stable PCMs (combination of organic and inorganic mixture). Besides, six different PCM arrangements in bricks (i.e. PCM layer on the outer side, on the middle layer, on the inner side, on the outer side and middle, on the middle and inner side, and on the outer side and inner side) are studied. The thermo-physical properties and latent heat of various PCMs (liquid and solid phases) were measured experimentally. The results showed that the duplex house with outer side PCM layer brick with OM29 PCM provides the best annual energy cost saving ($2079 in hot-arid climates and $2095 in composite climates), the highest carbon emission mitigations (87.80 ton-CO2/year in hot-arid climates and 88.42 ton-CO2/year in composite climates), and reasonable payback period (11.29 years in hot-arid climates and 11.21 years in composite climates).

Origin of the unusual property contrast in K2Bi8Se13 phase-change material

Phase-change materials are promising foundations for both nonvolatile storage and neuro-inspired computing applications. An attractive phase change material K2Bi8Se13 (KBS) was recently discovered to possess fast structural transition and outstanding property contrast, yet the underlying mechanism remains unclear. We conducted ab initio molecular dynamics simulations to investigate the transition of KBS from a crystalline to amorphous phase. Initiated by the Bi–Se bond breaking at the boundaries of atom blocks, the simulated phase transition proceeds through the conversion between BiSex octahedral and pyramid structures. Remarkable discrepancies in electronic structures and absorption spectra between the two phases are further illustrated by density functional theory simulations, which reproduce the experimental observations. The optical and electrical contrasts between the two phases are found to originate from the band edge states localized at various atom blocks that uniquely appear in the crystalline phase. These states provide pseudo one-dimensional transport channels with resonant bonding that may further intensify the electrical contrast. The distinct phase change properties compared with traditional phase change materials can be attributed to the hierarchical KBS crystal structure comprised of loosely bound atom blocks. The above findings pave an avenue toward the design of phase change materials beyond the traditional scope of the Ge–Sb–Te triangle map.

Numerical analysis of multiple phase change materials based heat sink with angled thermal conductivity enhancer

Phase change materials (PCM) RT-28HC, RT-35HC, and RT-44HC with three different melting temperatures, 29 °C, 36 °C, and 44 °C, with similar thermal properties, are considered. The PCM is oriented from the left to right side of the heat sink in its increasing order. The fins are attached to the heat sink longitudinally, and its orientation effects are studied low (100–500 W/m2) and high (1000–5000 W/m2) heat fluxes applied on the horizontal bottom surface of the heat sink. A 2D model is developed using ANSYS Fluent 19, and the fin orientation effects are investigated numerically. The orientation of fins at different angles such as 0°, +15°, +30°, +45°, +60°,-15°,-30°,-45°, −60° are considered. The effect of fins on the charging cycle is assessed by comparing a single and double PCM heat sink. Three initial conditions are investigated by altering the initial temperature 300 K, 303 K, and 310 K. At increasing heat input, the negative angled fins possess a higher melting rate. For different initial conditions, −60° provides higher enhancement, and +60° possesses prolonged melting for almost all cases. The performance of a triple PCM design is compared with single and double PCM counterparts under similar conditions.

A numerical study on applying the movable PCM design to disaster‐relief prefabricated temporary houses used in different climate regions to improve indoor thermal environments in summer

Prefabricated temporary houses (PTHs) are extensively used for temporarily accommodation disaster victims. However, the thermal environment inside PTHs can be intolerable in summer. Previous related studies showed the success of applying a movable phase change material (PCM) design to PTHs for improving indoor thermal environments in Chengdu, China; it only represented the “warm temperate-fully humid-hot summer” climate. Since various natural disasters may occur around the world, it became necessary to study the effectiveness of applying the movable PCM design to PTHs installed in other climate regions globally. Therefore, following the previous experimental and numerical studies where only one climate condition was considered, in the current article, a numerical study is reported on applying the movable PCM design to PTHs in 12 selected cities in different climate regions to improve their indoor thermal environments in July. The results from the numerical study showed that, in all the 12 selected cities in July, after introducing the movable PCM design to the PTHs, both the maximum indoor air temperature, the monthly averaged air temperature inside the PTHs, the daily peak and daily average indoor air temperature on the hottest day were lowered. It was further demonstrated that on the hottest day in July, the difference between the daily peak air temperature values inside the disaster-relief PTH with and without incorporating the movable PCM design varied from 2.12°C to 5.34°C, and that between the daily air temperature values varied from 1.53°C to 3.56°C. In all the 12 selected cities, although applying the movable PCM design to disaster-relief PTHs in July was functional, it was more effective for the following seven cities, that is, Singapore, Miami, Bangkok, Chengdu, Damascus, Hanoi, and Urumqi (with Δ $$ \Delta $$ values being not less than 300°C·h and Δ ′ $$ \Delta^{\prime } $$ being not less than 46%), with six of the seven cities located in both tropical and temperate climate regions, based on the evaluating criteria proposed in this article.

Phase-changing hydrogels incorporated with copper sulfide-carbon nanotubes for smart thermal management and solar energy storage

Organic phase change materials (PCMs) have great potential in solar energy storage and thermal management. Herein, a novel system of integrated photothermal-thermal storage function was designed and prepared based on sodium alginate (SA) hydrogel combined with photothermal materials (CuS-CNTs) and pure polyethylene glycol-6000 (PEG-6000). The CuS-CNTs composites were synthesized mainly by hydrothermal reaction, and the resulting CuS was a 3D nanoflower structure with excellent light absorption and photothermal conversion. When Ca2+ is introduced, SA underwent a cross-linking polymerization reaction to encapsulate CuS-CNTs and PEG-6000 to form light-thermal phase change hydrogel (LTPCH). With 93% PCM loading, the hydrogel exhibited a high latent heat of over 150.8 J/g and reliable thermal stability, as well as inherited the excellent photothermal properties of CuS. Inside the LTPCH, CuS-CNTs and PEG-6000 were in direct contact, and the heat energy generated from the photothermal conversion of CuS-CNTs can be immediately absorbed by PEG-6000, demonstrating efficient thermal management. The solar energy storage efficiency was as high as 91.4% under simulated sunlight. Light-thermal thermal storage composite hydrogels had great potential in solar energy storage systems, providing insights into the functional integration design of PCMs.

A template-method synthesis of mesoporous-MgO/expanded graphite for enhancing thermal properties of methyl palmitate-lauric acid phase change materials

Relatively weak thermal conductivity and antileakage performance of phase change materials (PCMs) limit their applications. The present work focuses on the development of a novel composite PCM (MP-LA/MgO/EG) based on the dispersion of expanded graphite (EG) and magnesium oxide (MgO) nanoparticles in a binary mixture of methyl palmitate-lauric acid (MP-LA). MgO/EG, a new supporting material, is assembled using expanded graphite and specially shaped MgO prepared with the surfactant-assisted high-temperature thermal decomposition method. In addition to maintaining the porous structure of EG and preventing the leakage of MP-LA, MgO/EG reduces the interface thermal resistance between the matrix and the PCM molecules because MgO maximizes heat conduction. The thermal conductivity of the proposed material (4.568 W/m/K) is 8.16 times higher than that of MP-LA, and its faster heat transfer rate is reflected directly in the infrared images. The enthalpy of MP-LA/MgO/EG-9 floats in a narrow range with the value of 1.88% during the process of heating-cooling cycles 100 times. The results reported herein can serve as a reference for the functional design of PCM supporting carriers that form good thermal conducting networks and provide the form-stable effect.

Heat transfer mechanism and structure design of phase change materials to improve thermoelectric device performance

In recent years, the use of phase change materials (PCM) to improve the output performance of semiconductor thermoelectric generators (TEG) and maintain the long-term work of TEG has received widespread attention. Because of the lack of a unified understanding of the existing PCM-TEG combination mode and PCM structure design, this paper first established a PCM-TEG coupling mathematical model, the accuracy of which is proved by experimental data. Secondly, for the three most common combinations of PCM and TEG, namely cold-sided, hot-sided and dual-sided PCM-TEG, the effect of PCM on TEG, the effect of finned PCM on system performance, and the system anti-interference ability when the heat source is unstable are respectively studied from the heat transfer mechanism. The results show that 1) PCM's high heat storage characteristics can effectively protect TEG and avoid device failure due to excessive temperature; 2) Designs of metal fins within PCM can effectively maintain advantages of the PCM and significantly enhance the temperature difference between the hot and cold ends of TEG, thereby significantly improving the system performance; 3) The cold-sided PCM-TEG system has the best output but the worst anti-interference ability compared to the hot-sided or dual-sided design. On a comprehensive basis, the dual-sided design is recommended in practice; 4) The cooling capacity of the PCM-TEG system significantly affects the performance. Enhancing the heat transfer coefficient of the cold end of the TEG can significantly improve PCM-TEG systems' performance.