Heat Conversion Efficiency Research Articles

Optimal dual-pressure evaporation organic Rankine cycle for recovering waste heat from compressed air energy storage (CAES)

Compressed Air Energy Storage (CAES) is an effective solution to the problems of the intermittency and volatility of renewable energy. However, the process of compressing air consumes energy and converts it into low-temperature waste heat, limiting the improvement of round-trip efficiency. This paper introduces the dual-pressure evaporation organic Rankine cycle (ORC) to recover the waste heat from the CAES system compression process, which enhances the round-trip efficiency. Optimal working fluids and design schemes of parallel and series dual-pressure evaporation ORCs are analyzed. The thermodynamic performance of two cycle types is compared. The exergy loss distribution characteristics of the dual-pressure evaporation ORC are explored, and the impact on the round-trip efficiency of the CAES system is evaluated. Results show that the parallel dual-pressure evaporation ORC has better performance with an optimum working fluid of R1234yf and a maximum waste heat conversion efficiency of 9.3 %. The round-trip efficiency of the CAES system will be relatively increased by 5.2 % by introducing the parallel dual-pressure evaporation ORC. The maximum exergy efficiency of the parallel dual-pressure evaporation ORC is 52.8 %, and the condenser and low-pressure stage expander have larger exergy losses, accounting for 33.8 % and 22.0 % of the total losses, respectively.

Heat transfer inhibition of corundum–mullite insulation tiles through composition regulation

AbstractThe increase in size and efficiency of gas turbines leads to higher temperature in the combustion chamber, putting greater demands on the performance of the thermal insulation tiles. Corundum–mullite has been used because of its high‐temperature resistance, thermal shock resistance, and low thermal conductivity. However, how to inhibit heat transfer through composition regulation while ensuring the safe use of high‐temperature insulation tiles is the key to improving the heat conversion efficiency of gas turbines. In this study, thermal insulation tiles were prepared by casting molding. On the basis of determining the optimal corundum/mullite ratio (22:45 wt%) in the aggregate, the thermal conductivity of the sample was reduced by adding MgO (2 wt%). The results show that phonon intrinsic and defect scattering, caused by changes in phase composition, effectively reduce the thermal conductivity of the insulation tile sample to 2.05 W·m−1·K−1, which is 34.71 % lower than the maximum value before regulation. During 30 cycles of thermal shock (air‐cooling at 1000°C), the residual strength gradually decreased and tended to be stable, with a minimum of 8.6 MPa, indicating that the thermal insulation tile can provide better thermal insulation without affecting the safety of gas turbines, providing new ideas and methods for improving the thermal insulation performance of high‐temperature thermal insulation materials.

Development of thermal insulation material using coconut and kenaf fiber for heat recovery enhancement

Abstract In line with the world’s Sustainable Development Goals (SDG), Malaysia aims to have a clean future energy. The main problem facing the energy revolution is the low conversion efficiency of low-grade heat to useful energy. During the process, a significant fraction of thermal energy is generally lost to the environment as waste heat. Waste heat accounts for 20-50% of industrial energy use, with Southeast Asia processing 40 million tonnes of oil equivalent. Heat losses especially in engines can reduce efficiency, leading to extensive studies to reduce heat loss and improve thermal performance. Heat recovery systems are being studied to recover lower-grade energy, but to the extent of the authors’ knowledge, the majority of them are not economically effective for low temperature waste heat. Therefore, the objectives of this study are to develop low thermal conductivity material for thermal insulators based on natural fibre and investigate their impact on thermal performance. The natural fibre-based materials that were chosen in this study are coconut husk and kenaf fibre due to their supposedly low thermal conductivity level and availability in the Southeast Asia region. The specimens were prepared using two different methods; the first two specimens using needle felting method and for the other two specimens epoxy resin was reinforced to bind the material together to become a polymer. The results revealed that coconut husk fibre reinforced with resin has the lowest thermal conductivity value among the four specimens with 0.0410 W/m.K and the lowest overall heat transfer coefficient of 2.73 W/m2.K, making it a possible thermal insulator to be proposed for heat recovery.

Influence of particle stacking modes on the fluidization characteristics of biomass particles in binary particle systems

Spouted bed is widely used in biomass combustion and other industrial production due to the advantages of good heat transfer performance and sufficient gas–solid mixing. In order to achieve higher heat and mass transfer performance and conversion efficiency, inert particles are often added to assist in the fluidization of biomass particles. However, the stacking patterns of different particles in a binary particle system can have some effects on particle flow, distribution, and bed stability. Therefore, in this study, the computational fluid dynamics–discrete element method was used to analyze the particle fluidization characteristics under four different particle stacking modes in a spouted bed. The results show that the average bed height of larger spherocylindrical particles is prioritized in binary particle systems. The void fraction of spherocylindrical particles tends to increase in the near-wall region, whereas spherical particles tend to decrease. When the binary particles are mixed at the initial moment, the change rule of vertical velocity of the two particles remains consistent. In addition, the vertical velocities of two kinds of particles when layered stacking is used are gradually close to each other only after a period of time. In addition, the orientation angle of the spherocylindrical particles in the spouted bed tends to be horizontal for both the single-component spherocylindrical particle system and the wall effect attenuates this phenomenon.

Numerical study on solar photovoltaic/thermal system with tesla valve

In recent years, photovoltaic/thermal (PV/T) systems have played a crucial role in reducing energy consumption and environmental degradation, nonetheless, the low energy conversion efficiency presents a considerable obstacle for PV/T systems. Therefore, improving heat conversion efficiency is essential to enhance energy efficiency. In this paper, the PV/T system with the Tesla valve is proposed to solve this problem. Firstly, the cooling effect is simulated and analyzed in the system with four different flow channel structures: semicircle, rectangle, triangle and Tesla valve. The results indicate that the system with the Tesla valve exhibits superior cooling performance. Subsequently, several factors including angle, valve number, valve type, and pipe diameter ratio for the Tesla valve are further studied through numerical and simulation analysis. The results reveal that Tesla valves demonstrate optimal cooling performance when possessing the following structural parameters: complete symmetry, more valves, a 30-degree angle and a pipe diameter ratio of 1. Finally, four different types of fluid are selected to explore the Tesla valve. The conclusion shows that nanofluids with high density, low specific heat, and high thermal conductivity also improve the cooling performance. Thus, the PV/T system with the Tesla valve exhibits good heat dissipation and energy storage efficiency, electrical efficiency can reach 16.32% and thermal efficiency reach 59.65%.

Colorimetric and photothermal double-model immunochromatographic assay based on MoS2@Au nanocomposite for high sensitive detection of imidacloprid in food

In this work, a colorimetric and photothermal double-model immunochromatographic assay for the detection of imidacloprid (IMI) was developed using gold nanoparticles (AuNPs) deposited on two-dimensional layered molybdenum disulphide nanosheets (MoS2 NSs). Here, as a signal amplification carrier, the AuNPs on the surface of MoS2 NSs can be well connected with antibody to prepare the photothermal signal probe, this probe has good biocompatibility and high heat conversion efficiency. It is worthing mentioning that the assay realizes the double-mode signal output of semi-quantitative visual detection and quantitative photothermal detection under 808 nm excitation. Under optimal conditions, the limit of detection (LOD) of assay based on photothermal model for IMI was 0.18 μg L-1 and the visual limit of detection (vLOD) of assay based on colorimetric model was 12 μg L-1. The proposed assay has good specificity and other neonicotinoid pesticide analogues have no effect on assay performance. The detection results of this assay were consistent with that of HPLC, indicating the good accuracy of this proposed quantitative detection method. This double-model assay can be used as a promising candidate for sensitive and rapid detection of IMI, which provides a new strategy for real-time monitoring of pesticide residues in food safety test.

Numerical Investigation of the Damage Effect on the Evolution of Adiabatic Shear Banding and Its Transition to Fracture during High-Speed Blanking of 304 Stainless Steel Sheets.

This paper investigates numerically the effect of damage evolution on adiabatic shear banding (ASB) formation and its transition to fracture during high-speed blanking of 304 stainless steel sheets. A structural-thermal-damage-coupled finite element (FE) analysis is developed in LS-DYNA considering the modified Johnson-Cook thermo-viscoplastic model for both plasticity flow rule and damage law, while further, a temperature-dependent fracture criterion is implemented by introducing a critical temperature. The modeling approach is initially validated against experimental data regarding the fracture profile and ASB width. Next, FE simulations are conducted to examine the effect of strain rate and temperature dependence on damage law, while the effect of damage coupling is also evaluated, aiming to highlight the connection between thermal and damage softening and attribute them a specific role regarding ASB formation and transition to fracture. Also, the influence of dynamic recrystallization (DRX) softening is studied macroscopically, while further, a parametric analysis of the Taylor-Quinney coefficient is conducted to highlight the effect of plastic work-to-internal heat conversion efficiency on ASB formation. The results revealed that the implementation of damage coupling reacts to reduced ASB width and provides an S-shaped fracture profile, while it also decreases the peak force and results in an earlier fracture. Both findings are enhanced when accounting further for DRX softening and a higher value of the Taylor-Quinney coefficient. Finally, the simulations indicated that thermal softening precedes damage softening, showing that the temperature rise is responsible for ASB initiation, while instead, damage evolution drives ASB propagation and fracture.

Light- and electro-driven phase change materials derived from activated porous biochar nanosheets and encapsulated polyethylene glycol

Biochar-based phase change materials (PCMs) are suitable for energy conservation to regulate the environment of greenhouses, but would benefit from higher specific surface area biochar to increase the polyethylene glycol (PEG) loading and enhanced thermal conductivity to promote efficient heat transfer. Moreover, since solar radiation is not constant for photo-thermal conversion, a material with an additional energy conversion process, e.g. electro-thermal conversion, would be advantageous. Herein, maize straw-derived activated porous biochar nanosheets were prepared and impregnated with PEG to afford PCMs. Due to their high specific surface area, the PEG loading capacity in the biochar nanosheets reaches 88.9%, with no leakage observed during phase transitions. The latent heat and photothermal conversion efficiency of the materials increase with the loading content of PEG. Hierarchical porous structures in the biochar nanosheets endow the material with a high thermal conductivity exceeding 0.585 W m−1 k−1. In addition, electro-thermal conversion of the materials was achieved due to increased graphitization of the biochar nanosheets. The electrical conductivity and electro-thermal conversion efficiency decrease with the loading content of PEG. The material with 85.7% PEG content is the most favorable in terms of thermal conductivity as well as light- and electro-driven phase change behaviors.

H2S‐Mediated Gas Therapy and HSP90 Downregulation Synergically Enhance Tumor Microwave Thermal Therapy

AbstractMicrowave thermal therapy (MWTT) is a novel clinical treatment of tumors via inducing thermal effect and anti‐tumor immune response, exhibiting advantages of deep penetration, minimal invasion, and high heat conversion efficiency. However, effective ablation is difficult to cover the entire tumor area, and heat‐shock protein 90 (HSP90) is often upregulated after ablation to generate heat tolerance of sublethal tumors and weaken the induced antitumor immune effect, resulting in a high rate of tumor recurrence and metastasis. Herein, a multifunctional nanoregulator of metal phenolic network‐coated ZnS (ZnS@Ga‐tannic acid, ZGT) is proposed to release H2S for synergically enhancing MWTT. Under the costimulation of MW radiation and acidic tumor microenvironment, ZGT can improve the MW thermal effects of tumors to promote thermal damage and release H2S to induce tumor apoptosis. The released H2S can also inhibit the production of ATP and then downregulate the expression of HSP90, strengthening the activated systemic antitumor immune response after ablation. This nanoregulator provides a new way for achieving compensation effect for MWTT. The strategy of H2S gas to downregulate HSP90 and positively regulate antitumor immune response introduces a novel direction for reducing the risk of tumor recurrence and metastasis after thermal therapy.

Constructing independent CNTs conductive network to boost combustion performance of metastable intermixed composites

AbstractNovel metastable intermixed composites (MICs) constructed by carbon nanomaterials are expected to achieve high energy content and high combustion efficiency, but traditional preparation technologies always bring barely improvement in performance. Herein, novel PVDF/CuO/Al@CNTs MICs with independent continuous carbon nanotubes (CNTs) conductive networks were prepared by thoroughly utilizing the conductivity and photothermal properties of CNTs. A conductive network can be constructed at the interface of each encapsulated PVDF/CuO/Al particle with the addition of >0.5 wt% CNTs. The great increase in electrical and thermal conductivity of PVDF/CuO/Al@CNTs MICs indicates excellent energy transfer efficiency across the sample. Significant enhancement of the combustion reaction has been achieved, with the minimum ignition energy and ignition delay time of PVDF/CuO/Al@CNTs3 reduced by ~31% and ~50%, respectively. This indicates that the CNTs with unique photothermal properties can be utilized as an effective igniter. Moreover, the optimal PVDF/CuO/Al@CNTs1 MICs enhanced the pressurization rate (~300%), energy output (~55%), and combustion velocity (~200%). The mechanism of the fast combustion reaction can also be discussed by the weak interface interaction and the energy conductive of the CNTs network throughout the sample. This work provides a modern strategy for strong combustion MICs that can be generalized and applied in the field of energetic materials.Highlights An independent continuous CNTs conductive network was prepared with a small amount of CNTs. The electrical and heat conversion efficiency is greatly improved. CNTs with unique photothermal properties can be utilized as an effective igniter. The laser sensitivity is improved, and the reaction energy, pressure, and pressure rates are significantly increased. The combustion performance was significantly improved, and more intense, and the combustion speed was significantly increased.

CsxWO3-doped PEG/sweet potato form-stable composites for light-thermal conversion and energy storage

Abstract Cesium tungsten bronze (CsxWO3)-doped PEG/sweet potato form-stable composites are fabricated through a facile two-step method of lyophilization and vacuum impregnation. Abundant starch microsphere enhances the PEG loading capacity above 72 % and also supplies capillary force as well as hydrogen bonding to improve the form-stability of the composites. Here, the latent heat, relative crystallinity (Xc), and light-thermal conversion efficiency of the system with 0.99 wt% CsxWO3 reach to 137.7 J/g, 97.7 %, and 83.5 %, respectively. The light-thermal conversion efficiency increases from 64.3 % to 91.1 % with 2.00 wt% CsxWO3. Besides, the composites exhibit improved thermal stability and excellent thermal reliability. The prepared bio-based composites with low-cost have broad application prospects in the field of energy storage.

Fresh water collection strategy: Invasive plant-based cellulose aerogels for highly efficient interfacial solar evaporation

Interfacial solar steam generation (ISSG) is promising technology to solve global scarcity of freshwater resources, hence highly efficient, robust photothermal conversion materials as key components for ISSG were urgently needed. Herein, the threat of invasive plant Solidago canadensis L. (SCL) to agricultural environment and ecosystem diversity was explored and further utilization was demonstrated by stripping and purification of raw SCL to three-dimensional crosslinked SCL-based cellulose aerogel (SCL-CA) with polyethylene glycol (PEG) as green cross-linking agent. After dopamine (DA) in situ polymerized on the SCL-CA surface, PDA@SCL-CA exhibits a high evaporation rate of 2.05 kg m−2 h−1 with photothermal conversion efficiency of 95.5 % under one sun upon the customized evaporation equipment with simulated seawater. The result is much better than that of other state-of-art samples due to the unique 3D-macro interlaced structure and hierarchical microcapillary structure of overpass bridge-shaped cellulose chains. The excellent outdoor experiment further demonstrated the practical application owing to the full solar spectrum absorption, superhydrophilicity, anti-salinity, robust structure, etc. Especially, the design strategy can be universal, and PPY@SCL-CA modified with polymerized pyrrole (PPY) can also work as a highly efficient photothermal material. The mild synthesis methods and abundant sources of raw material render it possible to fabricate efficient photothermal materials on a large scale, realizing the control of biological invasive species and resource utilization. Combining with the future upgrade of evaporator components, the heat conversion efficiency, water yield, and economic benefits of the evaporator would be further improved, which has broad application prospects in alleviating the freshwater crisis.

Numerical Evaluation of Heat Transfer and Conversion Efficiency by Tube Design and Flow Configuration for a Compact Steam-Methane Reformer

In the chemical industry, hydrogen (H2) production through steam-methane reforming is a well-established process. With the growing demand for H-fueled vehicles and charging stations, there is a need for compact reformers with efficient heat transfer capabilities. In this study, computational fluid dynamics simulations were performed to evaluate the methane (CH4) conversion and heat transfer efficiency of various reformer designs. These designs include single, double, and triple tubes, each with parallel- and counter-flow configurations between the reformate feed and heat source. The findings revealed substantial disparities in methane conversion between the tube designs and flow configurations. Notably, the triple-tube design outperforms single and double tubes, exhibiting higher methane conversion and improved heat transfer efficiency. This superior performance is attributed to the larger wall area facing the heat source and additional heat recovery from the reformate flowing in the inner annulus. This led to the highest temperature at the catalyst exit among the cases, increasing methane conversion, and the lowest reformate temperature at the reformer tube exit, which is also beneficial for the subsequent water–gas shift reaction process. Installing external fins on the reformer tube provided a more effective enhancement of heat transfer than using internal fins in the catalyst section. Regardless of the tube design employed, the counter-flow configuration consistently enhanced the heat transfer efficiency, resulting in 4.6–11.9% higher methane conversion than the parallel-flow configuration. Consequently, the triple-tube design with the counter-flow configuration achieved the highest methane conversion, offering flexibility in the reformer design, including the potential for lower heat input and a reduced catalyst volume.

Selective Nitridation of Ceramic Open Cell Foams for Efficient Photothermal Heating

AbstractThis study presents the synthesis of ceramic open cell foams as a new platform for photothermal energy conversion based on the inert structural ceramic alumina and the plasmonic transition metal nitride TiN. TiO2 precursor grains inside the mixed ceramic matrix are converted to TiN via the molten salt synthesis route. Photothermal measurements using an 850 nm LED as a light source show that the ceramic foams with only ≈5% TiN in the alumina matrix showed a 34% increased efficiency in converting light to heat compared to flat ceramic discs of the same composition. The TiN content in the flat discs does not affect the heat conversion efficiency, indicating that the available surface area and the material's ability to trap and direct light to the plasmonic nanostructures are the most important parameters for its photothermal activity. These results show the feasibility of synthesizing mixed ceramics based on inert materials like alumina and transition metal nitrides. Applications in solar heating, water evaporation, and related use cases of photothermal energy conversion can be realized with improved performance over 2D materials. Particularly processes that are based on continuous flow like solar thermal heating or photothermal catalysis will benefit from this new material platform.

Advanced electromagnetic shielding and excellent thermal management of flexible phase change composite films

Endowing the integration of electromagnetic interference (EMI) shielding and thermal management is of great practical significance but remains extremely challenging, especially EMI stability in solid-liquid phase transformation process. Here, innovative flexible composite phase change films (PF/AC/PEG-X (X = 2, 4, 6, 8)) was developed inspired by the unique inter-structure of seedpod composed by scattered honeycomb pores and large multicellular interlocking of lotus seeds and lotus houses. The rich porous structure of eucalyptus-derived carbon not only realizes the high load of PEG (67.4%) and enhanced heat conversion efficiency, but also complete the reflection and absorption of electromagnetic waves (59.83 dB), and develop the steady-state EMI properties during solid-liquid transition under photo-thermal interaction. Optimized PF/AC/PEG-2 film has highlighted a mechanical strength of 45.1 MPa, an energy storage density of 121.3 J/g, a photothermal conversion efficiency of 89.42%, high light/thermal cycle stability (95%), and excellent flexibility. This flexible composite phase change films are promising for a wide range of applications in efficient thermal management and electromagnetic shielding of electronic devices.

Plasmon-Mediated Solar Steam Generation over Au@Cu7S4 Yolk@Shell Nanocrystals

In recent years, solar steam generation has attracted extensive attention because it can address the shortage of water resources. Traditional techniques enabling solar steam generation are based on heating water under concentrated solar irradiation, suffering from low solar to heat conversion efficiency. By exploiting the heat localization effect from photothermal materials, the efficiency of solar steam generation can be significantly improved. Similarly, electromagnetic field confinement induced by plasmonic materials has also proven efficient for promoting solar steam generation. In this study, Au@Cu7S4 yolk@shell nanocrystals were prepared and employed as plasmonic mediums for superior solar steam generation. Here, Au was a typical plasmonic metal showing a plasmon resonance peak around 550 nm. Cu7S4, on the other hand, represented a self-doped plasmonic semiconductor capable of absorbing photons beyond 1000 nm. The combination of Au and Cu7S4 in Au@Cu7S4 nanocrystals allowed a broadband light absorption across the visible and near infrared regions. The superior solar steam generation over Au@Cu7S4 was attributed to the broadband light absorption and the enhanced solar to heat conversion efficiency rendered by the combined plasmonic effects of Au and Cu7S4.

Automated Open-Loop in Vitro photothermal TherapyUsing Near-Infrared Emitting Graphene Quantum Dots

Graphene-based materials have been the subject of interest for photothermal therapy due to their high light to heat conversion efficiency. Graphene quantum dots (GQDs) are expected to both possess advantageous photothermal properties and facilitate visible and near-infrared (NIR) fluorescence image-tracking, while surpassing the other graphene-based materials in their biocompatibility. To test these capabilities several different GQD structures were synthesized using top-down (RGQDs from reduced graphene oxide) and bottom-up (HGQDs from molecular hyaluronic acid) approaches. RGQDs and HGQDs possess nanometer-scale sizes, are hydrophilic, and exhibit fluorescence throughout the visible and NIR. The high biocompatibility of RGQDs (1.5 mg/ml) and HGQDs (1.7 mg/ml) and substantial absorption tail in the NIR make them suitable for biological photothermal therapy applications. In aqueous suspensions of RGQDs and HGQDs, a low power (0.8 W/cm2) 808 nm NIR laser irradiation facilitates heating up to 46.0 and 47.0 °C, respectively, making them sufficient for cancer tumor ablation. In vitro photothermal studies were performed via cost-effective open-loop automated approach involving a 3D printer head controlling the laser and a thermocouple. These experiments are carried out in a 96 well plate to show that GQDs can facilitate HeLa cancer cells heating up to 54.5 and 43.5 °C from 37.0 °C, leading to the inhibition of cell viability down to 23%. GQDs’ fluorescence in the visible and NIR effectively tracks their intracellular accumulation verifying effects of photothermal treatment. The combination of therapeutic and imaging capabilities makes GQDs developed in this work highly prospective anticancer agents.

Assessing Greenhouse Gas Emissions and Energy Efficiency of Four Treatment Methods for Sustainable Food Waste Management

Food waste (FW) increases with urbanization and population growth, which puts pressure on the treatment system, causing a variety of harmful impacts on the environment. Proper FW treatment is imperative for ecological integrity and public health. Even though FW treatment is an extensively studied topic, the sustainable FW treatment considering holistic-lifecycle-based environmental impacts has rarely been evaluated. This study addresses this gap through a comprehensive analysis of various FW treatment methods, including co-treatment with sewage, anaerobic digestion, incineration, and aerobic composting. The impacts of greenhouse gas (GHG) emission and energy use efficiency are assessed by analyzing diverse FW treatment methods in Shenzhen, China. The study indicates that FW addition to sewage does not adversely affect the current sewage treatment plant, but benefits GHG avoidance and energy recovery. Compared with the other FW treatment methods, FW anaerobic digestion avoids the most GHG emissions with −71.3 kg CO2 eq/FU and recovers the most energy with −223 kWh/FU, followed by FW co-treated with sewage. The energy conversion efficiency of the combined heat and power (CHP) unit greatly affects FW incineration, while energy consumption in incineration and anaerobic digestion (AD) process is relatively minor. Perturbation analysis pinpoints key parameters influencing outcomes, including CHP efficiency, GHG emission factor of local electricity, and chemical oxygen demand (COD) in FW with ratios of −13~−0.942, −0.518~0.22, and −13~1.01, respectively, that should be given special attention. This study sheds light on sustainable FW management strategies, not only in China but also transferrable to regions confronting similar challenges. Advocating ecologically balanced and resource-efficient approaches, the study aligns with broader aims of fostering sustainable development.

Realizing High Thermoelectric Performance in N‐Type Mg3(Sb, Bi)2‐Based Materials via Synergetic Mo Addition and Sb–Bi Ratio Refining

AbstractDeveloping thermoelectric (TE) performance is impeded by the compromise of TE parameters, resulting in inadequate conversion efficiency of heat to electricity. Herein, this work reports that Mo is a particularly effective additive in Mg3Sb2‐based alloys with significantly improved electronic transport via grain‐boundary engineering and band‐structure regulation synergy. In addition, phonon transport is simultaneously suppressed by employing multiple effects, lattice imperfection scattering, reduced phonon group velocity, and enhanced atomic disorder, leading to a minimum κlat = 0.52 W m−1 K−1 at 723 K. As a result, an outstanding ZT peak of ≈1.84 at 723 K and ZTav = 1.34 within 323–723 K are achieved in Mg3Sb2‐based alloys, and the corresponding fabricated single‐leg TE module shows an exceptionally high conversion efficiency of ≈12% under a hot‐side temperature of 450 °C. These results demonstrate the great potential for advancing mid‐temperature heat harvesting in Mg3Sb2‐based materials.

Co-gasification of rural solid waste and biomass in rural areas: Simulation and plant-scale process

Co-gasification technology is considered to be one of the most potential technologies for solid waste treatment, and the co-gasification treatment of rural solid waste (RSW) and biomass can effectively promote waste reduction and resource utilization. In the present study, the co-gasification of RSW and biomass in an updraft fixed bed gasifier was simulated using the Aspen Plus software, where the simulation results were validated via plant-scale experiments. In this scenario, the impacts of biomass source (i.e., rice husk, rice straw, tree bark and corn straw), co-gasification ratio (CGR) (0–40%) and air equivalence ratio (AER) (0.30–0.55) on the performance of the fixed-bed were investigated. Results showed that Aspen Plus could describe the plant-scale co-gasification process well. Besides, the tree bark-RSW system had the highest heat conversion efficiency of 6.00 MJ/kg the simulation temperature of the gasification layer increased greatly from 485 to 913 °C when the AER increased from 0.40 to 0.55. In addition, the co-gasification of RSW and tree bark could achieve the highest efficiency at the AER of 0.45 and CGR of 20% w, in which the gasification temperature reached 799 °C with the gasification efficiency of 57.17%. This study explored the use of co-gasification of RSW and biomass in rural areas by simulation and plant-scale processes, which promotes the commercial application of co-gasification technology and contributes to sustainable waste management in rural areas.