High Thermal Performance Research Articles

Straw bale construction towards nearly-zero energy building design with low carbon emission in northern China

With the aim of achieving carbon neutrality, bio-based construction is of increasing interest for decarbonization globally. Among the potential candidates, straw bale is promising due to its ready availability and energy efficiency benefits. However, thermal conductivities of straw bales can vary greatly due to construction details, which may lead to failures in meeting nearly-zero energy building (nZEB) design standards in real practice. In the context, this study applied thermal property and carbon emission assessment of full-size straw bale walls (SBWs) and construction of an experimental building in northern China. The results demonstrated that the thermal conductivities of different monitoring portions of the SBWs ranged from 0.067 to 0.088 W·m−1·K−1. This resulted in U-values (0.16 W·m−2·K−1) marginally higher than the lower limits of nZEB design, indicating the importance of addressing thermal bridging issues of SBWs. The SBWs without additional insulation layers therefore can satisfy nZEB design standards in the severe cold region after certain adjustments. Besides, when not accounting for carbon sequestration, SBWs generated the lowest emissions among the schemes in meeting U-value limits for nZEB design (at least 14.6% lower than those of timber walls), with increasing emission reductions as U-value limit decreased. The results indicated that SBW demonstrated effectiveness in carbon reductions with high thermal performance. The findings of the research can facilitate application of straw bales and development of clean construction and net-zero design in northern China.

Design and Thermal Performance of Ultra-Thin Flat Plate Heat Pipes with Composite Wick for Electronic Cooling

The rapidly increasing heat load and high-density packaging of electronic devices demand heat dissipation devices that possess miniaturization and high thermal performance. A series of ultra-thin flat plate heat pipes (UPHPs) with thicknesses of 1.2 mm was prepared to satisfy this demand. Strengthening rib optimization and capillary optimization were processed to restrict the entrainment limit and capillary limit of the UPHPs. Furthermore, surface modification technology with composite nanostructure coated was introduced to improve the surface wettability of capillary wick. Finally, the heat transfer capacity of the UPHPs was experimentally tested. The influence of capillary structure and liquid filling ratio on the heat transfer characteristic was investigated in detail. This work provides insight into the design and application of UPHPs for the new generation of electronic devices.

NUMERICAL AND EXPERIMENTAL INVESTIGATION OF SEMICIRCULAR SOLAR UPDRAFT TOWER SYSTEM EMPLOYING POROUS COPPER METAL FOAM

The numerical and experimental study was carried out under Iraqi weather conditions to verify the improvement of the performance of the solar updraft tower system SUTS by introducing porous metal foam as a heat-absorbent plate. a semicircular basin of the solar collector was divided into two equal identical quarters. A porous foam material was fixed on one of the basins while the other basin was fixed on a traditional copper plate. The positions of the metal foam absorber plate are changed with two inclination angles (0֯ and 18֯) and the optimum position is achieved when it gives the highest thermal performance. A finite volume modeling technique is used to solve the governing equations and radiation heat transfer equations by using ANSYS Fluent. The experimental part was conducted in Baghdad / Iraq at latitude 33.3°. The presence of the metal foam absorber plate caused a significant decrease in the average temperatures of the heat-absorbent plate. The maximum airflow temperature was recorded with an inclined angle of 18◦. The metal foam as a heat-absorbent plate enhanced the efficiency and the output power of the SUTS to about 51.9% and 47.2% respectively compared to the traditional plate.

Energy efficiency strategies for Brazilian social housing considering a life cycle perspective: Optimisation between thermal autonomy, energy consumption and costs

This study aims to establish optimal cases for energy-efficient social housing projects in Brazil, considering a life cycle cost-benefit analysis. Energy efficiency measures for the building envelope were evaluated in representative single-family and multifamily typology projects for the lower-income sector, considering thermal autonomy, energy consumption and cost indicators. The measures estimated in terms of macrocomponents allowed for comparative evaluation and association with costs. Cases were simulated in EnergyPlus to obtain the building’s expected operational consumption. With the macrocomponents and simulation data, Python routines were used to compute results for each proposed combination. Optimal cases that present high thermal performance in the national standard (NBR 15575) with cost-effectiveness, offering guidelines for projects in the 8 Brazilian bioclimatic zones, were established. Results presented in more detail for bioclimatic zone 8 showed optimal cases, with the increase in the percentage of hours of thermal autonomy reaching 65% to 71%, whereas that of a typical building was 30%, while life cycle cost related to the envelope showed reductions of up to 22%, even with higher initial costs. This study served as a basis for the new Brazilian policy proposed by the National Housing Office (SNH) to develop new social housing projects.

Numerical Investigation of the Effect of Ethylene Glycol with SnFe2O3 Hybrid Nanofluid on Heat Transfer in Flat, Face Step, and Radial Corrugated Microchannels

Nanofluid technology is one of the latest technics aims to enhance the heat exchangers working systems. The nanofluid is used because it has better thermal performance properties than common fluids like water. Tin Oxide (SnO2) and Ferric Oxide (Fe2O3) has used due to their availability and low cost for manufacturing. Flat, face step and radial corrugated microchannels have been studied at the Reynolds number range (4000-7000 Re). In this study, a hybrid nanofluid combined Ferric Oxide and Tin Oxide SnFe2O3 at (0, 5, 15%) of Tin Oxide concentration. The volume concentration of the nanoparticles was from (1-5)% suspended in ethylene glycol as base fluid due to its high thermal performance compared with water. The performance evaluation criteria (PEC) are studied and the results were validated with experimental and numerical results from previous studies. Performance evaluation criteria (PEC) studied the heat transfer in all study steps and found that the 15Sn85Fe2O3 hybrid nanofluid in ethylene glycol at 5% volume concentration in radial corrugated microchannel increased 104% compared with base fluid ethylene glycol in the flat microchannel. The performance evaluation criteria value has increased by 82% from flat microchannel to radial microchannel at 5% of volume concentration of 15Sn85Fe2O3 hybrid nanofluid

Preparation and thermal properties of phase change energy storage composite material based on modified fly ash

Fly ash (FA) is a kind of porous solid waste from coal-fired power plant, It is nominated as adsorption carrier for solid-liquid phase change material (PCM), While shape-stabilized composite phase change materials (SSCPCM) prepared directly has low thermal performance due to limited adsorption capacity of FA. Therefore, modification methods have become increasingly attractive, and four modification methods were investigated to improve the adsorption capacity of FA. Modification treatment experiment proved that the surface structure of FA is significantly corroded. Test analysis displays that the surface microspheres in FA have abundant particles and pores by destroying the Si–O–Si and Si–O–Al network structures. The mass ratio of Al/Si increased from 0.59 to 0.726, and the specific surface area of FA has been greatly increased. Experimental results indicate that alkali modification followed by high-temperature calcination is the desirable process for FA. For obtaining high thermal performance materials, two kinds of SSCPCM were prepared according to the mass ratio of 65:35 by vacuum adsorption while Alkali modified FA serves as carrier, binary eutectic of lauric acid-stearic acid (LA-SA) and lauric acid-myristic acid (LA-MA) serves as PCM respectively. The LA-SA/AFA-OH (NaOH alkali leaching treatment for FA) and LA-MA/AFA-OH (NaOH alkali leaching treatment for FA) could reach 54.49 J/g and 47.15 J/g and the phase transition temperature (PTT) is 37.45 °C and 32.36 °C, respectively. The SSCPCM has good thermal, chemical and morphological stability over 500 thermal cycles, while the LA-MA/AFA-OH had higher stability and less thermal performance slightly. Research finding provide a feasible process for composite modification of FA, and application scope is extended due to high thermal performance of composites.

Effect of Rotating Channel Turning Section Clearance Size on Heat Transfer Characteristics of Supercritical Pressure Hydrocarbon Fuel

For the problem of power generation turbine blade ablation in hypersonic vehicles, hydrocarbon fuel carried by the vehicle is used to cool the turbine blades. In order to fully utilize the cooling capacity of hydrocarbon fuel, the structure of the cooling channels needs to be optimized. In this study, a variable clearance hydrocarbon fuel cooling channel is applied for the first time to the rotating turbine blades of a hypersonic vehicle to enhance the heat transfer ability of hydrocarbon fuel. The effect of clearance size on the heat transfer performance of hydrocarbon fuel under rotating conditions is investigated. The accuracy of the calculations is verified by comparison with experimental data. The results of the study show that the heat transfer performance can be significantly improved by changing the clearance of the turning section. The clearance size 2.5 D channel has the highest thermal performance with a maximum improvement of 1.8 times. The law of change of thermal performance is affected by crossing the critical temperature point, as it is different before and after the crossing. Thermal performance changes from decreasing then increasing to increasing then decreasing as the clearance size increases for high rotation speed conditions as the temperature of the entrance straddles the critical temperature. The Nusselt number first increases and then decreases for all channels with different clearance sizes with an increasing rotational speed. The friction factor changes from first increasing and then decreasing to decreasing and then increasing as the clearance size increases for high rotation speed conditions as the temperature of the entrance straddles the critical temperature.

Polymer Template Synthesis of CuOx/Clay Nanocomposites with Controllable CuOx Formation

AbstractMetal oxides have the excellent functions including high thermal stability, electrical properties, catalytic performance, and adsorption properties of acid gases such as CO2 via the acid‐base interactions. However, they suffer from low reserves, porosity control, and low adsorption efficiency per weight compared with lightweight materials including carbon and silica. To solve these issues, various methods for supporting metal oxides on porous carriers, such as decomposition‐precipitation and impregnation, have been investigated, but controlling the formation of metal oxide on clay nanosheets remains as a challenge. Herein, we developed a soft‐template method for supporting metal oxide (CuOx) nanoparticles on activated clay nanosheets. The intercalation of polyethyleneimine (PEI)−Cu2+ complexes between the layers of clay nanosheets followed by calcination to construct CuOx and remove the PEI templates afforded CuOx/clay nanocomposites. The constructed CuOx/clay nanocomposites had the close porosity to that of clay. Tuning the Cu2+/PEI ratio in PEI−Cu2+ complex allowed to control CuOx states (loadings, particle sizes, etc.). Tuning of the supporting conditions allowed constructing a structure suitable for CO2 uptake. These findings will contribute to the development of the material science of metal oxide nanoparticles and their hybrid materials in diverse fields including CO2 adsorbents, energy devices, and catalysts.

Thermal Performance and Parametrical Analysis of Topologically-optimized Cross-flow Heat Sinks Integrated with Impact Jet

In this work, two novel cross-flow heat sink structures are firstly designed by means of topological optimization with the objective function which aims to achieve the minimum temperature difference and pressure drop or with the other objective function which aims to get the minimum mean temperature and pressure drop, namely, TOS1 and TOS2. By analyzing the effect of six channel heights Hch of TOS1 and TOS2 with the evaluation criterion j/f, we obtain that TOS2 with the Hch of 5 mm has the best ability of heat dissipation. A impact jet part is then implemented into the TOS2 to form a new integrated heat sink, that is, ITOS. Numerical results show that the ITOS exhibits much better thermal performance than TOS2 and TOS1. The in-depth parametric study on the flow and thermal behaviors of the ITOS shows that the average temperature of the bottom surface of the ITOS increases with the height of the channel of the bottom plate, while the temperature difference peaks at the Hch of 2 mm. The increase of the ratio of cross-flow fluid to total fluid leads to a reduction of the heat dissipation ability, implying that the high thermal performance of the impinging jet plays an important role in the heat transfer process of such ITOS. Finally, the convective heat transfer experiment of the ITOS with the Hch of 5 mm is conducted to testify the optimization and simulation results.

Evaluating cooling and thermal performances of a double pipe rectangular Earth-to-Air Heat Exchanger provided with a convection zone

Earth-to-Air Heat Exchanger performances depend on many parameters, among them the pipe geometric shape which is also found be influential. On account of their large exchange surface, rectangular buried pipes are more performing compared to the circular ones. In this study, an innovative technique of improving heat transfer consisting in incorporating a convection zone within these systems is proposed. In view of its high thermal performance and harmless nature compared to organic liquids, water is used for filling the convection zone within a double pipe rectangular underground exchanger operating in cooling mode and submitted to the summery climatic conditions of the Algerian Saharan region. Moreover, a thorough investigation is conducted for assessing the response of the double pipe rectangular exchanger to the variation of its sizing and operating parameters in the presence of such a layer. The findings reveal that the presence of a convection zone makes the double pipe rectangular exchanger more performing in terms of the air temperature reduction and cooling energy production, even in the case where the basic system usually is ineffective due to using a larger pipe section, a smaller length, or higher air flow. For instance, the outlet temperature supplied by the exchanger with a convection zone at a pipe section of 1256 cm2 is found to dwindle by 2 °C compared to the basic system. Likewise, the average efficiency at a pipe length of 20 m rises to 83 % for the former, while drops to 72 % for the latter. It is also shown that at high air flow of 1780.4 m3/h, the cooling energy yielded by the improved exchanger rises to more than twice of that obtained with the unimproved one. Further, the integration of a convection zone is a cheaper and useful way for more enhancing the performance of commercial rectangular PVC pipes on account of their low aspect ratio. Thus, it follows that the novel technique of using rectangular buried pipes integrated with convection zones can to be considered as a powerful improving way that could be eventually combined with other techniques for further maximizing the profitability of these systems.

Thermal performance of a radial-rotating oscillating heat pipe and its application in grinding processes with enhanced heat transfer

Grinding difficult-to-machining materials can generate massive heat. The heat generated by grinding easily accumulates in the grinding zone (the contact area between workpiece and wheel), leading to high temperatures, which harms the grinding quality and efficiency. Radial-rotating oscillating heat pipe (RR-OHP) can achieve high thermal performance and can potentially to apply in grinding with enhanced heat transfer. The RR-OHP is supposed to be designed in the grinding wheel to improve the heat transport ability, in this case, grinding heat can transfer out directly via the grinding wheel. RR-OHP needs to obtain high thermal performance under radial rotations, while the related research is still insufficient. In this paper, the influence of centrifugal acceleration (0 – 1620 m/s2), working fluid properties (methanol, DI water), and heat flux (1.5 × 104 – 4 × 104 W/m2) on the heat transport capacity are studied. A prototype of a grinding wheel combined with RR-OHPs is developed. A grinding simulation by the wheel is built to demonstrate the enhanced heat transfer of RR-OHPs in grinding process. Results show that the increment of heat flux and centrifugal acceleration can improve the thermal performance of RR-OHPs. The thermal resistance of RR-OHP filled with methanol is smaller than that of RR-OHP filled with DI water. In addition, under the condition that grinding speed of 12 m/s, infeed speed of 360 mm/min, and 1 mm depth of cut, the grinding wheel embedded with 16 RR-OHPs can transfer out 79% of total heat and control the temperature under 262 °C, based on the grinding simulation. On the contrary, the grinding wheel without RR-OHPs transfers only 34% of the total grinding heat, and the temperature reaches up to 766 °C.

Effect of Flow Resistance of Floating-Type Check Valves on Heat Transfer Characteristics of an Oscillating Heat Pipe

Abstract An oscillating heat pipe with check valves (CVOHP) is an attractive heat transfer device for future spacecraft with considerable heat dissipation and ground applications. This study aims to clarify the effect of the flow resistance of floating-type check valves on the heat transfer characteristics of the CVOHP using a one-dimensional slug flow model, which simulates the five-turn CVOHP used in the on-orbit experiment by the authors. The numerical simulations were conducted for different flow resistances, positions, and numbers of check valves. The results showed that the thermal resistance of the CVOHP increases with the flow resistance of the check valves, while there is no significant effect on the startup characteristics. The thermal resistance increased by more than 100% in the worst case, and the recommended flow resistance coefficient of the check valve was below 100 in this study for high thermal performance. The thermal resistance increases with an increasing number of high-resistance check valves but is less affected by the position of the valve. Additionally, the higher the heat input, the greater the effect of the flow resistance of the check valves. According to the findings in this study, it is necessary to control the flow resistance of the floating-type check valves at a low level for the high thermal performance of a CVOHP.

A resveratrol based active ester cured epoxy film with low dielectric loss and high thermal performances

The production of epoxy resins with low dissipation factor (Df) remains an alluring yet challenging task. In this work, we successfully synthesized a novel resveratrol based active ester (ResE) by a one-step method using the renewable resveratrol as raw material. The structure of ResE was characterized using FTIR and NMR techniques. The phenol biphenyl epoxy (SQXN-324) was cured with ResE, the SQXN/ResE system boasted a favorable dielectric constant (Dk) of 2.78 and dissipation factor (Df) of 3.5 × 10−3 at a high frequency of 10 GHz. Additionally, the SQXN/ResE system exhibited impressive thermal performances, with a 5 % weight loss temperature (T5%) of 368 °C, a residual carbon of 34 wt% at 800 °C in N2 atmosphere, a glass transition temperature (Tg) of 154 °C, a coefficient of thermal expansion (CTE) of 61.9 ppm/°C from 25 °C to Tg and the CTE of 130 ppm/°C from Tg to 250 °C. These findings suggested that a biomass curing agent for epoxy with low Df and high thermal performances were successfully developed, it had potential applications in the high frequency communication field and microelectronics industry.

Multifunctional flexible composite phase change material with high anti-leakage and thermal conductivity performances for battery thermal management

Composite phase change material (CPCM) as passive battery thermal management system (BTMS) still confronted many challenges such as easy leakage, high rigid and low thermal conductivity. In this study, a multifunction flexible CPCM with high anti-leakage and thermal conductivity performances has been proposed which is utilized the polymerizing and crosslinking reaction with polyethylene glycol and hexamethylene diisocyanate to address the leakage of CPCM in essence. The results revealed that the CPCM exhibited excellent antileakage and elastic performance. Especially, the thermal conductivity of CPCM is obviously improved by 2.8 times owing to the synergistic effect of 3 wt% aluminum nitride and 2 wt% carbon nanotubes. Besides, the maximum temperature of the battery module with multifunction flexible CPCM can be controlled below 45 °C even at 1.5C discharge rate, and the corresponding temperature difference is maintained within 4.3 °C. With these outstanding properties, the multifunctional flexible PEAC can provide an efficient solution to improve the thermal safety of battery packs in applications, which will significantly promote the development of EVs.

Vapor Exchange Induced Particles‐Based Sponge for Scalable and Efficient Daytime Radiative Cooling

AbstractPassive daytime radiative cooling technology (DRCT) has recently gained significant attention for its ability to achieve sub‐ambient temperature without energy consumption, making it an attractive option for space cooling. The cooling performance can be further improved if radiative cooling materials also exhibit high thermal insulation performance. However, synthesizing radiative cooling materials that possess low thermal conductivity while maintaining mechanical durability remains a challenge. Here, a vapor exchange method is developed to prepare particles‐based poly(vinylidene fluoride‐co‐hexafluoropropylene) sponge materials for scalable and efficient daytime radiative cooling. By tailoring the particle diameter distribution, high solar reflection (94.5%), high infrared emissivity (0.956), and low thermal conductivity (0.048 W m−1 K−1) are achieved, resulting in a sub‐ambient cooling of 9.8 °C under direct solar irradiation. Additionally, the sponge material exhibits good mechanical durability, sustaining deformation with a strain up to 40%, making it adaptable to diverse scenarios. A radiative cooling material with mechanical durability and thermal insulation can thus pave the way for large‐scale applications of DRCT.

Three-Dimensional Macroporous rGO-Aerogel-Based Composite Phase-Change Materials with High Thermal Storage Capacity and Enhanced Thermal Conductivity.

Three-dimensional porous network encapsulation strategy is an effective means to obtain composite phase-change materials (PCMs) with high heat storage capacity and enhanced thermal conductivity. Herein, macroporous reduced graphene oxide (rGO) aerogels with adjustable pore size are prepared by the emulsion template method and hydrothermal reduction process. Further, the shape-stabilized rGO-aerogel-based composite PCMs are constructed after the combination of 3D porous rGO supports and paraffin wax (PW) through vacuum melting infiltration. By regulating the pore structure of the rGO aerogel network, the rGO-based composite PCMs achieve excellent energy storage properties with a phase-change enthalpy of 179.94 J/g for the loading amount of 95.61 wt% and an obvious enhancement in thermal conductivity of 0.412 W/m-1·K-1, which is 54.89% higher than pristine PW and enduring thermal cycling stability. The obtained macroporous rGO-aerogel-based composite PCMs with high thermal storage and heat transfer performance effectively broaden the application of PCMs in the field of thermal energy storage.

Fabrication of intrinsic flame-retarding rigid polyurethane foam with enhanced compressive strength and good thermal insulation

The rigid polyurethane foam (RPUF) with excellent flame retardancy, high compressive strength and good thermal insulation performance is of great importance to its widely application, especially the application in high-rise building exterior wall materials. In this work, two kinds of flame-retarding polyols (DADP and APDP) containing phosphorus and nitrogen elements were prepared via a simple salinization reaction and reacted into RPUF chains. When only 15 wt% of APDP was incorporated, the material passed the UL-94 V-0 rating with a limiting oxygen index (LOI) of 24.5% while 20 wt% of DADP incorporated to realize the same flame-retarding effect. For the RPUF/APDP15, the peak heat release rate (PHRR) decreased by 28.2% comparing to the neat RPUF and the fire growth rate (FIGRA) was the lowest 8.3, indicating the lowest flame spread speed among all the flame-retarding RPUF. The compressive strength of the RPUF/APDP15 material increased by 41.8% comparing to that of neat RPUF, mainly causing by the good compatibility and the enhancement of hardness of polyurethane via the benzene ring. Moreover, it was concluded that the gas-phase mechanism dominated in enhancing the flame-retarding effect for the RPUF material, and the APDP showed a higher flame-retarding effect with a higher content of phosphorus and nitrogen elements than that of DADP.

Bio‐based building components: A newly sustainable solution for traditional walls made of Arundo donax and gypsum

AbstractTo contribute to the use of bio‐based materials in the building sector, a novel bio‐based wall panel, with a high thermal performance level, is proposed in this work. The panel is based on an ancient rural technique, widely diffused in southern Italy, which makes use of Arundo donax L. canes combined with gypsum plaster to build walls and ceilings of rural buildings. The enhancement of the thermal capacity of these panels by means of the introduction in the canes of a natural wax oleogel (WO) is proposed in this paper. A specific experimental campaign aiming at the comparison of traditional and innovative panels was carried out to assess the enhanced thermal performance of the proposed solution. The maximum value of heat flow absorbed from the panel with WO was 61.08 W/m2 around a mean panel temperature of 24°C, corresponding to the melting temperature range of the WO. The panel without WO at the same temperature absorbed an incoming heat flow of 34.64 W/m2 which is about 57% of the panel with WO. The panel with WO released at a temperature of about 27.5°C, a heat flow of 43.42 W/m2. At the same temperature of about 27.5°C, the panel without WO released a heat flow of 34.38 W/m2 which is about 80% that of the panel with WO. The results highlighted that the addition of natural WO has enhanced the thermal capacity of the panel facilitating heat dissipation through the borders. These characteristics make the panel a suitable component for internal partitions of controlled temperature zones such as residential rooms, storage food areas, livestock buildings, and where it is necessary to obtain a constant environmental temperature. In particular, the null or low toxicity of the panel's materials allows for partition use, also in hygienically safe environments.

Performance improvement of a double tube heat exchanger using novel electromagnetic vibration (EMV) method in the presence of Al2O3-water and CuO-water nanofluid; An experimental study

In this research, the novel approach of the electromagnetic vibration (EMV) method was utilized for the first time to increase heat transfer in a double-tube heat exchanger (DTHEX). In this method, a magnetic turbulator (comprising a magnet and an oscillator) was installed inside a central tube that vibrated using an AC magnetic field. The influences of various parameters such as the geometry of the oscillator, magnet position, employing nanofluids, and fluid flow were assessed on the thermal-frictional behavior. The thermal enhancement factor (TEF) was assessed to select the optimal option. The studied options were economically evaluated based on energy efficiency. According to the results, the maximum heat transfer rate could be achieved when the magnet is positioned at 0.374. L from the tube inlet. The highest value observed for overall heat transfer was related to CuO-water 1% nanofluid, which was 277.5% more than simple heat exchanger. Also, the findings showed that heat transfer can be increased up to 13.3 times the energy used and reached to TEF = 3.92, which is a very significant number. Regarding the high potential of the EMV in reaching high thermal performance, it can be utilized as a game changer to save materials, energy, and compaction of the heat exchangers and solar systems.

Mannitol enhanced thermal conductivity and environmental stability of highly aligned MXene composite film

Multifunctional thermal management materials with high flexibility are urgently required to tackle the heat dissipation issues of highly integrated electronics. MXene is considered a promising two-dimensional (2D) material for preparing composite with high thermal conductivity. However, there still is a challenge to prepare highly aligned MXene composite for simultaneously achieving high thermal performance and excellent mechanical properties. Herein, a novel MXene composite film was synthesized by vacuum-assisted filtering MXene nano-sheets suspension containing non-toxic and pollution-free mannitol. Under the connection of mannitol, MXene nano-sheets in the MXene/mannitol composite film form a highly aligned structure, resulting in outstanding thermal and mechanical properties. In-plane and through-plane thermal conductivities are 36.3 and 1.06 W m−1 K−1 for the MXene/mannitol composite film prepared using MXene suspension with a mannitol content of 0.2 mol/L, which are higher by 172% and 193% than those of pure MXene film, respectively. As the heat sink for a high-power LED, the MXene/mannitol composite film also demonstrated an excellent heat dissipation efficiency outperforming pure MXene film. Moreover, the MXene/mannitol composite film exhibited noteworthy mechanical property and stable thermal conductivity after bending for 300 times. Our findings provide a promising approach to prepare high-performance heat spreader for the thermal management of modern electronic components.