Energy Recovery Applications Research Articles

Dual-Band Electrochromic Supercapacitor Utilizing Metal-Organic Coordination Polymer with Multi-Redox Feature.

Electrochromic supercapacitors, which indicate energy states through optical color changes, are gaining significant attention for their potential in energy saving and recycling. In this study, a novel metal-organic coordination polymer (DTPB-MCP) is successfully synthesized using an N,N'-diphenyl-1,4-phenylenediamine (DTPB)-functionalized phenanthroline ligand. The resulting DTPB-MCP film demonstrated desirable electrochromic performance in both the visible light (ΔT:77.6% at 730nm) and near-infrared (ΔT: 49.2% at 1410nm) regions, as well as decent energy-storage capabilities (16.4mFcm- 2 at 0.1mAcm- 2), attributed to the presence of multiple redox centers. Furthermore, a hybrid electrochromic supercapacitor is also developed by combining DTPB-MCP with V₂O₅ (DTPB-MCP//V₂O₅), showcasing a significant optical contrast (47.6% at 750nm and 14.5% at 1420nm), an acceptable capacitance of 11.5mFcm- 2 with good rate performance, and impressive cycling stability (maintaining 81% of capacitance after 2750 charging/discharging cycles). In addition, >60% of electric energy can be reused to drive small household appliances during the bleaching process. The design principles outlined in this study offer valuable insights into the development of high-performance dual-band electrochromic energy-storage materials, highlighting their potential applications in energy recovery and reuse.

Low-cost cascade thermoacoustic electric generator for energy harvesting

The cascade thermoacoustic heat engine has garnered significant attention for its ability to convert various heat sources into acoustic power without the challenges of acoustic streaming. By integrating it with a commercial loudspeaker, it can be further developed into a novel, low-cost thermoacoustic electric generator. This study aims to design and evaluate a thermoacoustic electric generator capable of producing several watts of electricity. The system consists of a cascade thermoacoustic engine, comprising a standing-wave and a traveling-wave unit, coupled with a B&C 6PS38 loudspeaker in a linear configuration. Atmospheric air is used as the working fluid, and standard market components, such as PVC and steel pipes, are proposed to minimize costs. Unlike traditional thermoacoustic generators, this system uses commercially available loudspeakers and a linear configuration, offering a cost-effective solution for low-wattage power generation, free from the issue of acoustic streaming. This makes it suitable for small-scale, distributed energy systems. The numerical simulation tool DeltaEC is employed to design and assess the system's performance. The optimal configuration is 4 m long, with the standing-wave and traveling-wave units centrally positioned. Operating at a frequency of 74.56 Hz, the system generates 90.18 W of electrical power with a total heat input of 1046.74 W and an external load resistance of 19.77 ohms. This corresponds to a heat-to-acoustic efficiency of 18.41 %, an acoustic-to-electric efficiency of 68.98 %, and an overall heat-to-electric efficiency of 8.62 %. The study also emphasizes the importance of operating conditions and impedance matching between the cascade engine and the loudspeaker. These findings represent progress toward developing an affordable thermoacoustic generator for energy recovery and other applications.

Numerical investigation of multiphase flow through self-affine rough fractures

Multiphase flow through fractures has great significance in subsurface energy recovery and gas storage applications. Different fracture and flow properties affect flow through a fracture which is difficult to control in laboratory experiments. Here, we perform lattice Boltzmann simulations in an ensemble of synthetically generated fractures. Drainage simulations are performed at different capillary numbers, wettability, and viscosity ratios. We track the invading front and quantify breakthrough saturations and show that roughness and wettability have a strong effect on fluid invasion through a complex fracture. Invading a more viscous fluid results in more stable displacement regardless of the capillary number while at very low capillary numbers, fluid migration is dependent on the inherent structure of the fracture. We develop a fluid displacement phase diagram in a single rough fracture and compare our results from that in the literature. Finally, we extend the phase diagrams across multiple fractures and demonstrate the importance of natural fracture features of roughness and wettability in identifying stable versus unstable displacement regimes during multiphase flow through rough fractures. Our work presents an end-to-end numerical pathway for testing on experimental data and expanding numerical data sets for testing combinations of different physical phenomenon and make valuable predictions on fluid flow through rough fractures.

Submillimeter‐Scale Superlubric Triboelectric Nanogenerator

AbstractTriboelectric nanogenerator (TENG) for mechanical energy harvesting has been regarded as one of the most prospective energy technologies for the new era. However, inevitable material wear during triboelectrification results in output reduction and even failure of the TENG. In this work, a submillimeter‐scale superlubric TENG (SS‐TENG) is reported that enables ultra‐low friction coefficient (µ) and stable power generation. By using the micro/nano‐processing technology, the interdigital electrodes are embedded into the dielectric layer as a flat surface, on which the highly‐hydrogenated diamond‐like carbon (PLC) is deposited as the triboelectric layer to effectively reduce the friction coefficient. The frictional properties are systematically investigated at different parameters, in which a submillimeter‐scale (130 µm) superlubricity state (µ = 0.0084) is achieved at 4 N, 2 Hz and nitrogen atmosphere. Meanwhile, the SS‐TENG has a maximum power density of 3 mW m−2, which can remain stable at the superlubric condition. This work has first realized the freestanding‐mode superlubric TENG in submillimeter scale and provided a viable strategy for the development of long‐lifetime TENG, which may have great applications in frictional energy recovery from mechanical components, human joint motion, and the natural environment.

Design and development of a novel Four-Links rotational hybrid Energy-Harvesting suspension system compatible with conventional suspension technologies

This study introduces a novel rotational Energy Harvesting Shock Absorber (EHSA), specifically designed for use alongside existing vehicle suspension systems. Addressing issues faced by standalone EHSAs, this design incorporates a four-bar mechanism coupled to a rotary energy recovery system. The proposed EHSA system, dubbed the FL-EHSA (Four Links Energy Harvesting Shock Absorber), is based on link connections and is highly versatile. It has the potential to significantly improve vehicle efficiency by harnessing energy usually wasted by traditional shock absorbers. Using a geometric definition process influenced by various factors such as vehicle suspension type and commercial availability of components, the FL-EHSA system was modeled, and bench-tested to validate the system’s energy recovery potential and performance. The movement of the mechanism was analyzed to achieve the target damping value matching the value of a conventional suspension and to maximize efficiency through DOE analysis and to avoid mechanical locking (singular positions). It explains the effect of backlash in mechanical components through simulation and highlights the importance of using dedicated gearboxes for energy recovery. In addition, this work highlights the untapped potential of four-bar mechanisms in automotive energy recovery applications. Moreover, the proposed design is easily integrated into any vehicle, making it a promising solution for EHSA systems.

Co-adjustable guide vane and diffuser vane to improve the energy generation potential of an axial-flow pump as turbine

Operating an axial-flow pump as turbine (APAT) with a high head can be a cost-effective solution for energy recovery applications. However, axial-flow pumps are characterized by a low head, which makes it difficult for an APAT to achieve high efficiency. In this study, computational fluid dynamics–based numerical simulations were performed using steady and unsteady Reynolds-averaged Navier-Stocks equations and a shear stress transport reattachment modification turbulence model to investigate how the energy performance and operating range of an APAT can be improved under low-head conditions. The experiment was conducted to evaluate the accuracy and reliability of the numerical results. Adjusting the diffuser vane (DV) and guide vane (GV) were identified as candidate solutions. The adjusting mechanism was designed and presented in both 2D drawings and 3D model. Further simulations were performed to evaluate the effect of the clearances at the hub and shroud of the GV and DV. While the clearances at the GV had no adverse effect on the energy performance, clearances at the DV greatly reduced the energy performance because of the formation and growth of leakage vortex flows. Adjusting the DV improved the energy performance more than adjusting the GV. A co-adjustable GV and DV is a comprehensive solution that was found to increase the efficiency of the APAT by 40.15 % under low-head conditions and weaken vibration and noise by suppressing the separation flow in the GV domain.

Research and application of thermal energy recovery and automatic monitoring system for motor equipment

In order to achieve an automatic monitoring system for the operation status of motor equipment, the author proposes a research and application based on the thermal energy recovery and automatic monitoring system of motor equipment. The author first analyzes the operating characteristics of the motor and collects four basic parameters of the motor, namely voltage, current, speed, and temperature, in order to determine whether the motor is in normal working condition. Secondly, the system combines electrical parameter detection and acquisition, wireless network technology, industrial field bus technology, and computer user software to achieve remote real-time monitoring, control, and management of the motor?s remote travel status. This enables the entire system to achieve intelligent, networked, and systematic management, solving the technical problem of real-time control and system management that cannot be achieved in motor systems distributed in multiple locations. Finally, the monitoring results indicate that after installation and debugging, the data is displayed on the upper computer. This effect is the data collection of the motor during low speed operation, which is reflected in real-time on the control panel. The actual parameters of the motor were compared with the test parameters of this system, and the test basically achieved the desired effect, with accurate detection data.

Energy Recovery Applications of Microbial Fuel Cells in Wastewater Treatment

Energy Recovery Applications of Microbial Fuel Cells in Wastewater Treatment

Resorufin retainment by extracellular DNA ensures efficient extracellular electron transfer of Geobacter biofilm

Electrochemically active bacteria (EAB) have promising applications in renewable energy recovery, biofuel production, environmental remediation, and wastewater treatment. Resazurin (RZ) is an effective exogenous electron mediator to facilitate extracellular electron transfer (EET) in EAB, but it is not fully understood that how it catalyzes EET within thick electroactive biofilm. Using Geobacter sulfurreducens as a model EAB, this study investigated the effect and mechanisms of RZ-mediated electron transfer in anode biofilm in a bioelectrochemical system. It was found that the amendment of RZ substantially enhanced current generation of anode biofilm, and the facilitating effect of RZ remained even after fresh electrolyte replacement without RZ replenishment. As an intermediate product of RZ, resorufin (RR) was the actual electron shuttle retained within the entire anode biofilm, responsible for the observed stable electron shuttling efficiency. The retention of RR in anode biofilm might be the consequences of insoluble RR deposition and RR binding with extracellular DNA (eDNA) through intercalative interactions. This study provided in vivo and in vitro evidences for the first time that eDNA provided binding sites for RR in Geobacter biofilm, and proposed a novel electron shuttling mechanism of phenoxazine catalyzing efficient EET of electroactive biofilm.

The utilisation of thermally treated poultry farm waste for energy recovery and soil application

The thermal treatment was analysed of poultry farm waste, excrement and litter, and their mixture. Two thermal treatment methods were chosen: Torrefaction at 300 °C and hydrothermal carbonisation (HTC) at 250 °C. The characterisation of raw materials and solid products was performed by proximate and ultimate analysis, and analysis of the high heating value. Thermogravimetric analysis (TGA) was performed of the combustion of raw materials and solid products in an air atmosphere. The kinetic and thermodynamic parameters were determined according to the Flynn–Wall–Ozawa (FWO) kinetic model. The contents of total organic carbon, chemical oxygen demand, total nitrogen and total phosphorus, as well as the content of total phenols, were determined in the process fluids. In addition, a germination test was performed with garden cress.The results show that the torrefied biomass had a higher carbon (C) content and a higher calorific value than raw biomass. The FWO kinetic model proved to be suitable for describing the kinetic of combustion of the tested samples' high fitting coefficients. The Eα for torrefied litter, excrement and their mixture ranged between 129 and 338, 108–550 and 136–489 kJ/mol, while for the HTC-treated samples generally lower Eα values were measured, 187–364, 121–229 and 126–428 kJ/mol, respectively. Germination tests with garden cress and analysis of nutrients showed that the tested products of torrefaction and HTC have a perspective for agricultural use at a sample concentration of up to 10 wt% in the substrate.

First Principle Investigations on Structural, Mechanical, Electronic, And Thermoelectric Properties of XCoP (XTi, Zr, Hf) Half Heusler Alloys for Energy Recovery Application

AbstractXCoP (XTi, Zr, Hf) half Heusler alloys are investigated through density functional theory in stable non‐magnetic phase. The exchange‐correlation functional Generalized Gradient Approximation (GGA) is used to study these alloys. The equilibrium lattice constants and corresponding ground state energies of the studied alloys are calculated in stable γ‐phase. All these three reported alloys exhibit semiconducting behavior with corresponding bandgap values of 1.40, 1.29, and 1.38 eV for TiCoP, ZrCoP, and HfCoP, respectively. The studied alloys are mechanically stable and ductile in nature. The obtained thermoelectric figure of merit for p‐type TiCoP, ZrCoP and HfCoP are 0.5, 0.6, and 0.7 at 1200 K. Similarly, the figure of merit obtained for n‐type TiCoP, ZrCoP, HfCoP are 0.54, 0.37, and 0.31, respectively, at the same temperature. The investigated favorable transport properties of these alloys show that they are the potential candidates for waste heat energy harvesting application.

Hybrid sensible-latent heat thermal energy storage using natural stones to enhance heat transfer: Energy, exergy, and economic analysis

Latent heat thermal energy storage addresses the mismatch between energy supply and demand; however, phase change materials (PCM) commonly have the issue of low thermal conductivity. Natural stones, as low-cost and environmentally friendly sensible heat storage media, are used to enhance the heat transfer of the PCM in the current study. Different stone types, sizes, and filling heights are tested, and a comprehensive energy, exergy, and economic analysis is performed. Results indicate that granite has the best heat transfer enhancement performance owing to superior thermal diffusivity, which accelerates the melting by 108 % (initial temperature: 23 °C; heating temperature: 75 °C). Basalt with high specific heat contributes to the large energy capacity. The total exergy is hardly influenced by the stone size ranging from 15 mm to 40 mm, where the minimum is only 5.1 % lower than the maximum. The exergy storage rate benefits from stones surrounding the inner tube and is increased by 246 % with a filling height of 112.0 mm. The 40 mm-sized stones are the most cost-effective in the current testing conditions, and a 560 % increase in the economy is achieved. This study demonstrates a high-performance, low-cost, environmentally friendly energy storage configuration and provides comprehensive information for potential energy recovery applications.

Road Piezoelectric Power Output Model and Experimental Study under Bidirectional Vehicle Load Excitation

Recently, piezoelectric transducers have gained significant attention for energy recovery applications in road engineering. However, in laboratory tests, vehicle loads are often simplified using vertical vibration loads, thus ignoring the role of vehicle tangential loads. In this study, a power output model of a piezoelectric transducer under vertical and tangential loads was proposed through theoretical analysis. A bidirectional cyclic dynamic load test was conducted on the piezoelectric-concrete specimens in combination with a large dynamic and static straight shear instrument, and the power output law of the piezoelectric transducer under vertical and horizontal shear was investigated. The results revealed that the vertical vibration load was the main factor affecting the output performance of the piezoelectric transducer; however, with the addition of the tangential load, the electric energy output of piezoelectric pavement increased with an increase in the horizontal shear rate and displacement. When vibrating vertically (200 kPa and 4 Hz), the electric energy output of piezoelectric pavement was 4.979 μW. However, under the action of vertical vibration and horizontal shear with the working conditions of 200 kPa and 4 Hz, and 0.1 mm and 1 Hz, the electric energy output of piezoelectric pavement was 21.04 μW, which was 3.2 times that of the vertical vibration load alone. Therefore, by considering the influence of vehicle tangential loads, the power output of piezoelectric transducers can be calculated more accurately, which provides a reference for actual installed capacities in real engineering applications.

Enhanced Thermoelectric Properties of p-Type Bi0.5Sb1.5Te3-Cu8GeSe6 Composite Materials.

Bismuth-telluride-based thermoelectric materials have been applied in active room-temperature cooling, but the mediocre ZT value of ∼1.0 limits the thermoelectric (TE) device's conversion efficiency and determines its application. In this work, we show the obviously improved thermoelectric properties of p-type Bi0.5Sb1.5Te3 by the Cu8GeSe6 composite. The addition of Cu8GeSe6 effectively boosts the carrier concentration and thus limits the bipolar thermal conductivity as the temperature is elevated. With the Cu8GeSe6 content of 0.08 wt %, the hole concentration reaches 5.0 × 1019 cm-3 and the corresponding carrier mobility is over 160 cm2 V-1 s-1, resulting in an optimized power factor of over 42 μW cm-1 K-2 at 300 K. Moreover, the Cu8GeSe6 composite introduces multiple phonon-scattering centers by increasing dislocations and element and strain field inhomogeneities, which reduce the thermal conductivity consisting of a lattice contribution and a bipolar contribution to 0.51 W m-1 K-1 at 350 K. As a consequence, the peak ZT of the Bi0.5Sb1.5Te3-0.08 wt % Cu8GeSe6 composite reaches 1.30 at 375 K and the average ZT between 300 and 500 K is improved to 1.13. A thermoelectric module comprised of this composite and commercial Bi2Te2.5Se0.5 exhibits a conversion efficiency of 5.3% with a temperature difference of 250 K, demonstrating the promising applications in low-grade energy recovery.

An Overview of Energy Recovery from Local Slaughterhouse-Based Gallus gallus domesticus Greasy Residues and Latest Applications

Gallus domesticus is one of the world’s most consumed animals, with a significant presence in all parts of the planet. Chicken oil appears to be a credible raw material in the context of alternative energy research. This study focuses on a literature review to highlight the chicken’s energy potential and the application of energy recovery from local slaughterhouse-based Gallus gallus domesticus greasy residues and it is proposed to make biodiesel from the fatty residues of Gallus gallus domesticus. The transesterification reaction takes place at 60°C. Methanol is used in a 1 : 6 oil-to-alcohol mass ratio. Catalysis is carried out with 1% (m/m) potassium hydroxide (KOH). The accepted reaction time under light agitation is 120 minutes. The reaction yield is estimated to be 85.6%, and the biodiesel produced is characterized. The postcharacterization values are consistent with the EN14214 biodiesel standard. Gas chromatography coupled with mass spectrometry reveals the intrinsic composition of the acids derived from the developed biodiesel methyl esters. The latter reveals a predominance of oleic acids with a value of 29.47% and palmitic acids with a value of 29.21%. The viscosity of greasy residues appeared to be relatively high at 69.32 mm/s. The low calorific value is 38775.363 KJ/Kg and the cetane index is 50. It has been observed that, for 1000 g of fat waste, it is possible to extract by cooking 507.807 g of oil, or an extraction yield of 51%. Fatty chicken residues from tropical market areas can be used as a raw material for biofuel development.

Thermal performance of various adiabatic section lengths of closed-loop pulsating heat pipe designed for energy recovery applications

This experimental study aims to emphasize on thermal performance and temperature variation of the closed-loop pulsating heat pipe (CLPHP) affected by various adiabatic section lengths. A capillary copper tube has been bent to have 10 and 20 meandering turns to form the CLPHPs with 1.78 mm internal diameter. The evaporator section length was 150 mm, which was the same as of the condenser section length. The adiabatic section length was varied from 75 to 150, 300, and 450 mm. Ethanol, R123, and water was selected to be working fluid with the volumetric filling ratio of 50%. Hot water was pumped through the heating jacket for supplying the heat input to the evaporator section. Heat flux selected as the thermal performance in this study was measured by means of the calorific method across the cooling jacket enveloping the condenser section. It could be concluded that effect of the adiabatic section length has two different trends that are: (i) When the adiabatic section length increases, the heat flux continuously increases until the evaporator section length exceeds a certain value, the heat flux then decreases. And (ii) when the adiabatic section length increases, the heat flux continuously increases. The different effects between both trends are depended on the working fluid’s flow velocity, surface tension, density, and viscosity.

Environmental impacts and nutrient distribution routes for food waste separated disposal on large-scale anaerobic digestion/ composting plants.

Centralized biological treatments, i.e., anaerobic digestion (AD) and in-vessel composting (IVC), were supposed to be the promising processes for the disposal of food waste (FW) after source separation, while the systematic benefits were unclear for FW with high water content, salt and oil and thus influenced the selection by the local decision-makers. In this study, two large-scale working AD and IVC plants were compared for environmental impacts, nutrient recovery and economic benefits. For unit amount of FW, 89.26kg CO2-eq was released in IVC mainly due to 47.89kWh electricity consumption, and 57.02kg CO2-eq was produced in AD. With the application of compost and energy recovery, 26.88 and 93.55kg CO2-eq savings were obtained in IVC and AD, respectively. NH3 emissions were the main contributor to acidification (0.35kg SO2-eq) in IVC, while AD exerted less impact on acidification (0.09kg SO2-eq) and nutrient enrichment (0.25kg NO3-eq) attributed to the counteract of energy recovery. 2029 would be the inflection point for global warming potential in AD with more clean energy applied in electricity mix in China. For nutrient recovery, more C (8.3%), N (37.9%) and P (66.7%) could be recovered in compost, while those were discharged via leachate and biogas residue in AD. The cost of IVC was 16 CNY/t (2.40 USD/t) lower than AD. Combing the three key indexes and the sale routes of products, IVC was recommended to be used in areas dominated by agriculture and forestry industries, and AD was more suitable for large cities.

Torrefaction Upgrading of Heterogenous Wastes Containing Cork and Chlorinated Polymers

Torrefaction of two mixed wastes composed of cork and chlorinated polymers was studied at temperatures from 200 to 350 °C, for residence times of 30 and 60 min. These wastes were recovered from sandwich panels with cork core, have different contents of cork biomass and chlorinated polymers and present poor fuel properties for energy recovery applications. The raw wastes and the produced biochars were characterized for proximate and ultimate analysis, chlorine content, mineral composition, calorific value, mass yield, energy density, particle size distribution, and adsorption capacity towards cationic and anionic dyes. Torrefaction enabled the production of biochars with mass yields from 97.2 to 54.5%, with an increase in 12.1 to 37.9% in apparent density relative to the raw wastes, and HHV from 18.2 to 20.7 MJ/kg. Nevertheless, the chlorine content of the biochars was increased to values higher than 5%, inadequate for solid fuels. Dechlorination of the biochars by washing with hot water enabled 84 to 91% removal of the chlorine species achieving final concentrations lower than 1%, without significant reduction in the biochars calorific values. For the waste with higher polymer and ash content, the torrefaction process reduced the heating value; therefore, energy valorization was not adequate. Both the raw wastes and the biochars were tested as adsorbents for cationic and anionic dyes. After activation with KOH, both the raw materials and the biochars had removal efficiencies higher than 90% for methylene blue, a cationic dye often found in industrial effluents. The results showed that torrefaction combined with hot water washing converted these wastes to biochars with the potential for energy or material valorization contributing to a circular economy in the cork industrial sector.

Paper industry wastewater treatment by electrocoagulation and aspect of sludge management

The paper production process comprises various manufacturing steps and generates an enormous amount of effluent, which consists of a large variety of contaminated chemicals. The higher color and chemical oxygen demand (COD) of the wastewater create a negative effect on all living forms and the natural environment. Electrocoagulation is a versatile process for the elimination of color and COD content from wastewater. In this study, the EC treatment has been used to identify the ideal conditions using several process variables such as pH, current density, time, and the dose of electrolyte. COD and color were reduced by up to 68% and 94%, respectively. Afterward, the treated water was compared with the standards of the world health organization (WHO) and the central pollution control board (CPCB) to find out the suitability of treated water for reuse for farming purposes. Germination tests of mung beans were conducted, and it was observed that the EC treated water is suitable for irrigation. The corrosion rate of mild steel was determined to be 2.85 mils/year, which has shown the short life span of mild steel electrodes. Furthermore, sludge produced by the EC process was analyzed and characterized for physicochemical analyses by using a variety of analytical techniques. The 69.93% iron content of the sludge was also recovered using the acid digestion method. After the physicochemical analyses, it was observed that sludge could also be utilized as a compelling supplement for plant growth, energy recovery, and industrial applications. According to this study, treated water could be a powerful alternative for reducing freshwater consumption in agricultural areas and increasing water availability in water-scarce areas. Effect of operating parameters on electrocoagulation treatment of pulp and paper industry wastewater, treated water and sludge management. • The higher COD and color 68% and 94%, respectively, were removed from wastewater by using EC treatment. • The greater removal of pollutants occurred at a near neutral pH. • It was observed that there was an encouraging improvement in the biodegradability index of wastewater after EC process. • Treated water is found to be suitable for reuse in agriculture. • The produced sludge could be a compelling supplement for plant growth, energy recovery, and industrial applications.

Mechanical Destabilization and Cage Transformations in Water Vacancy-Contained CO2 Hydrates

Clathrate hydrates show wide applications in energy recovery and storage, CO2 capture and storage, and other sustainable technologies. Water vacancy in clathrate hydrates is a common defect; however, its effects on the mechanical properties of clathrate hydrates, especially CO2 hydrates, have not been well studied. Herein, the mechanical characteristics of CO2 hydrates with three different types of water vacancy defects are investigated for the first time through molecular dynamics simulations with several popular water force fields. It turns out that the mechanical properties of CO2 clathrate hydrate vary with the type of water vacancy and water force field. Upon critical strains, a variety of unconventional cages of 425862, 425863, 425864, 4151062, 4151063, and 4151064 form, of which 4151062 predominates and is identified to be transient and a clathrate intermediate in forming 425862, 425863, and 425864. Moreover, diverse cage transformations of 51262 ↔ 4151063, ↔ 4151062, ↔ 425863, ↔ 425864 and 512 ↔ 4151062, ↔ 425862 occur via two distinct transformation mechanisms including insertion/removal and rotation of a pair of water molecules. This study provides new perspectives on the mechanics and microstructural transformations of CO2 hydrate, which are crucial for evaluating the formation and mechanical stability of CO2 hydrate-bearing sediments as well as the CO2 geological storage by hydrate-based technologies.