Energy Recovery Research Articles

Remanufactured Waste Tire By-product Valorization: Quantitative–Qualitative Sustainability-based Assessment

Automotive tires are a major waste stream and there are currently numerous options for reusing, recycling, and remanufacturing the waste tire rubber (WTR) and other components. Some competing technologies (retreading, product repurposing, energy recovery, pyrolysis oil, waste-tire crumbing, and devulcanized rubber) are discussed here to demonstrate the broad scope of possible applications and identify the advantages/disadvantages of the processes. Based on the industrial maturity of the processes, this study performed a qualitative–quantitative fuzzy analysis of twelve alternative by-products of WTR, including 1) devulcanized or desulfurized rubber; 2) tiles, mats, and rod barriers; 3) composite materials; 4) bitumen; 5) asphalt; 6) heat energy; 7) crude oil; 8) diesel; 9) char and carbon black; 10) gasification gas; 11) activated adsorption carbon; and 12) lightweight concrete. Quantitative sustainability considerations were applied to weight the technical, economic, environmental, and social sustainability factors according to their importance, while qualitative factors were applied to weight the sustainability criteria of productivity, reliability, efficiency, waste tire size range, remanufacturing time, remanufacturing cost, ergonomics, human development, and employment potential based on insights from the published literature. Comparative literature-based statistical analysis of potential tire resources and conventional waste-tire recycling was performed. The results identified remanufacturing of WTR into devulcanized rubber sheets as the best sustainable business option with the highest sustainability index of 0.628, while lightweight concrete was the worst by-product option with a low sustainability index of 0.012. Other very-high-potential options include producing value-added rubber products and composite materials from the devulcanized rubber. These findings provide valuable insights for stakeholders in the field of waste-tire management and small-to-medium businesses looking to add further value to their WTR products. Furthermore, these findings could guide international research to help focus on the most sustainable use of WTR.

Addressing the dollar crisis by investigating underlying causes, effects, and strategic solutions in emerging economies

Foreign exchange reserves (FER), especially dollar assets, are vital for a developing country to maintain economic stability, foster growth, and protect against unexpected amendments. In recent years, particularly since the onset of COVID-19, several emerging countries have experienced significant economic hardship due to a crisis in foreign reserves. This has led to inflation and disruptions in supply chains, healthcare, and various service facilities. Despite the gravity of this issue, previous studies have not investigated the causes and consequences of such sudden crises. This study aims to fill this gap by investigating the causes and consequences of sudden FER crises in a developing country, specifically Bangladesh, through a systematic review. The study also explores innovative process-oriented policies to mitigate the immediate FER crisis. The systematic literature review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. It included 90 articles published between 2020 and 2023. The results discovered that the FER crisis in Bangladesh has been triggered by both external factors (such as the COVID-19 pandemic, the Russia-Ukraine conflict, trade imbalances, and remittances) and internal factors (including large infrastructure projects, complexities in the banking sector, local project subsidies, a managed floating exchange rate, and an over-reliance on the ready-made garments sector). These factors escorted deflation of the national currency, causing further inflation, declining domestic purchasing capacity, and raising concerns about food security. Additionally, price hikes and unauthorized storage of daily necessities made accessing daily essentials challenging for locals. The government has implemented three policy interventions, including managing consumer demand, safeguarding the supply of goods, and regulating continuous market monitoring to overcome the challenges. This study proposes eight innovative process-oriented policy recommendations for mitigating the immediate foreign exchange crisis and promoting sustainable economic development. Overall, this study offers valuable contributions in developing sustainable global economic policies. It fosters improved recovery and reuse of materials and energy while advancing long-term growth in developing nations.

Experimental Energy Recovery from a Backpack Using Various Harvester Concepts

Experimental Energy Recovery from a Backpack Using Various Harvester Concepts

A fast charge algorithm for Li-ion battery for electric vehicles

The renewable solar energy industry and electric vehicle industry are today seeking for fast battery pack recharging methods to achieve higher performances, and fast energy recovery for energy storage systems (ESS) and for electric vehicles. The charge rate of batteries impacts directly the temperature which in turn impacts the capacity fade, thus it should be kept low to prevent the cells from warming up. This not only limits the charging rate but also puts us on a trade-off, a long lifetime or a fast recharge. In this study, we tried to achieve fast charging using a new charging method that combine two charging methods, without much deterring the capacity of the battery, in order to be able to maintain a long battery lifetime. Charging time of around 82 min was achieved for a 1.8 Ah battery. We compared our findings with the literature with known charging profiles.

Research progress of energy regenerative suspension systems

As energy saving and recycling in the automobile industry becoming a hot topic today, the energy recovery and regeneration system attracts the attention of a large number of researchers. However, unlike the energy recycling system of the braking system, the suspension is a relatively more immature technology. This article focuses on the summary of the current development of the energy recycling suspension system. It starts with a brief introduction to suspension systems, including their definition and several types of typical suspension systems with their structures and principles. After that is the description of four types of energy recycling suspension systems: hydraulic type, air pressure type, electric type, and mechanical type. It shares their principles, structures, workings, and the research achievements of others contemporary. The following is a comparison of the four types of energy recovery and regeneration suspension systems from several different aspects. The last part of this article is the summary conclusion of this research, mainly about their development prospect in the future.

Application of energy recovery mechanisms in wearable devices

Wearable devices have almost become a necessity in modern-day society due to their multifaceted functions, providing fitness tracking and health monitoring. Apart from this foundational role, daily wearable devices play a significant role in helping with health recovery, such as Mechanical Exoskeletons, in our high-demand society. However, one of the primary limitations of these devices is their dependency on finite battery life. This review paper aims to address this problem with the concept of energy recovery (ER) technology, which could be a potential solution for prolonging the operational time of wearables. These methodologies are primarily based on the theory of energy conservation and efficiency models, branching out into different aspects of thermodynamics, piezoelectricity, and the basic principles of human motion. Through the analysis of academic journals and primary studies, this review aims to provide a detailed explanation of how ER technology would work from various perspectives, identify constraints within the use of this technology, and suggest directions for future investigation. The objective is to promote the integration of energy recovery technologies into wearable devices, ultimately enhancing their efficiency for users.

BiOClxM1-x (M=I, Br) solid solution-coupled CdS photocatalysts for enhanced visible light-driven organic pollutants degradation with simultaneous hydrogen production

The construction of Z-scheme heterojunction stands out as one of the most effective modification methods for enhancing the performance of photocatalysts. Therefore, BiOClxM1-x (M=I, Br) solid solution-coupled CdS (BiOClxM1-x/CdS) Z-scheme photocatalysts were successfully synthesized by a hydrothermal-precipitation method. BiOCl0.8I0.2/CdS exhibited notable photocatalytic performance with a hydrogen yield of 261 μmol/g, which was 2.23, 1.56 and 1.44 times higher than that of CdS, BiOCl/CdS and BiOCl0.5Br0.5/CdS, respectively. This improvement can be attributed to two key factors: (1) the formation of BiOClxM1-x (M=I, Br) solid solution enhances visible light absorption; (2) The formation of BiOCl0.8I0.2/CdS (M=I, Br) Z-scheme heterojunctions inhibit the recombination of photogenerated carriers to prolong the lifetime of photogenerated carriers, thus increasing the utilization of the photogenerated carriers. Moreover, BiOCl0.8I0.2/CdS also showed good photocatalytic activity in ROW-DFHP (residual organic wastewater from dark fermentation for hydrogen production), with a hydrogen production rate of 42.83 μmol/g and a mineralization rate of organic pollutants of 31.73%. Cycling experiments, XRD and SEM of the samples before and after the photocatalytic reaction showed that BiOCl0.8I0.2/CdS has good stability. Furthermore, the mechanism of BiOCl0.8I0.2/CdS for the photocatalytic degradation of organic pollutants and simultaneous hydrogen production was proposed, offering a novel strategy for organic wastewater purification and hydrogen energy recovery.

Energy Efficiency Analysis of Waste-to-Energy Plants in Poland

The issue of enhancing energy recovery efficiency is a key concern within the European Union’s climate protection efforts. In particular, it applies to all processes and plants for the harvesting, gathering, and conversion of energy. The abandonment of fossil fuels in favour of alternative energy sources, and the increasing of energy efficiency and its recovery, is now a widely accepted direction of energy development. This study focuses on facilities that recover and process energy from municipal waste left after recycling processes, known as waste-to-energy (WtE) plants. These plants’ energy recovery efficiency is governed by the R1 Formula in EU countries. This report is based on an analysis of four years of operational data from selected Polish municipal waste incinerators, supplemented by a discussion of various studies on energy recovery efficiency. The primary objective of this report is to evaluate the effectiveness of these plants in contributing to sustainable waste management and energy recovery. The main effect of the developed report is the set of results of the energy recovery efficiency factor values, determined based on the R1 formula valid in the EU legislation, tabulated and graphically illustrated, and calculated for five selected Polish waste-to-energy plants. The presented results, with their graphical interpretation, discussion, and conclusions, provide insights into several factors influencing the value of the R1 efficiency factor. They can be a valuable contribution to operators of waste-to-energy plants, especially those operating in countries outside the EU.

DC electric field assisted heat extraction evaluation via water circulation in abandoned production well patterns: semi-analytical and numerical models

Geothermal energy, recognized for its clean and vast developmental potential, finds untapped promise in many oil fields developed through water injection. However, challenges such as the high costs associated with drilling and development, the expansion of water-clay expansion, and low rock permeability have constrained the broader exploitation of geothermal resources. Here, to address these challenges and harness low-permeability geothermal energy from abandoned wells, this work introduces a novel approach: DC-assisted circulation water injection technology. This study employs the Green function, Newman product, and boundary element methods to develop semi-analytical and numerical models, incorporating a DC electric field to simulate the optimization effect of this field on heat extraction. This work evaluates and optimize the lifetime and economic effects of abandoned wells using the Non Sorting Genetic Algorithm II. Results show that the semi-analytical model monitors the reservoir temperature parameter to optimize the timing for circulation water injection. Additionally, our numerical model demonstrates that, over a span of 5,000 days, a network of wells could generate a revenue of $9.158 million. In summary, DC-assisted abandoned wells to develop geothermal reservoirs is not only feasible but also enhances reservoir permeability and porosity through an electrical conductivity effect, significantly improving heat energy recovery.

Systematic Opportunity Scan of Energy Recovery Technologies Applied to Trucks with Electric Refrigerated Units

This article presents an original research methodology that combines insights from patents and academic research, offering a unique perspective on energy recovery technologies for trucks equipped with refrigeration units. The purpose of the study is to perform a functional analysis of existing solutions and to suggest a mechanism for exposing unexplored areas and opportunities for innovation. To achieve this goal, a systematic opportunity scan is presented, investigating patents and conducting a state-of-the-art search of existing technologies. This scan classifies a diverse range of solutions, elucidating their interconnections and providing an overview of the existing technological area, covering system components and technical trends. Thus, the main functions and components are listed, as well as the system requirements. Once the functions have been surveyed, a morphological matrix is proposed, and five main functions are analyzed. This methodology makes it possible to list the majority of the possible solutions for the functions analyzed, taking into account the components observed in the literature review and patents, including new components raised by the research group. Finally, with the morphological matrix structure, it was possible to combine unexplored elements, achieving innovative solutions.

Sleep Posture Influences Metabolic Rate And Vigilance in The Common Whitethroat (Curruca Communis).

Migration is an important life-history strategy that is adopted by a significant proportion of bird species from temperate areas. Birds initiate migration after accumulating considerable energy reserves, primarily in the form of fat and muscle. Sustained exercise, such as during the crossing of ecological barriers, leads to the depletion of energy reserves and increased physiological stress. Stopover sites, where birds rest and restore energy, play a fundamental role in mitigating these challenges. The duration of resting at stopover sites is influenced by environmental and physiological conditions upon arrival, and the amount of body fat reserves plays an important role. While sleep is recognized as essential for all organisms, its importance is accentuated during migration, where energy management becomes a survival constraint. Previous research indicated that individuals with larger fat reserves tend to sleep less and favor an untucked sleep posture, influencing energy recovery and anti-predatory vigilance. We explored the relationship between sleep behavior and posture, metabolic state, and energy conservation strategies during migration in the common whitethroat (Curruca communis). We were able to confirm that sleeping in a tucked position results in metabolic energy savings, at the cost of reduced vigilance. However, whitethroats did not show alterations of their sleep patterns as a response to the amount of stored reserves. This suggests that they may not be taking full advantage of the metabolic gains of sleeping in a tucked posture, at least at this stage of their migratory journey. We suggest that, to achieve optimal fuel accumulation and maximize stopover efficiency, whitethroats prioritize increased foraging over modulating their sleep patterns.

Modeling of energy recovery processes in railway traction power supply systems

Regenerative braking of trains can provide significant energy saving and a sizeable reduction in greenhouse gas emissions. The efficiency of energy recovery can be defined using an efficiency indicator equal to the product of the free-fall acceleration and the fraction of potential energy used in the recovery. Its slope dependence is well approximated by a polynomial of the third degree. The operating conditions of the traction power supply system of the mountain pass section of the main railway were modeled. The results obtained allowed the following conclusions to arrive at: regenerative braking is accompanied by circulating currents in adjacent inter-substation areas and leads to an absolute and relative increase in electrical energy losses in the traction network; the share of active energy losses rises by several times; the energy recovery causes a change in the direction of active energy flows at traction substations with a steep increase in reactive power consumption by trains; the energy recovery produces a significant decrease in voltage on the current collectors of electric locomotives; the voltage on the section under consideration, with three trains weighing tons decreased to 23 kV due to the large reactive energy consumption. © 2024 The Authors. Published by Elsevier Ltd.

Fluorophilic Sigma(σ)‐Lock Self‐Healable Copolymers

Although F‐containing molecules and macromolecules are often used in molecular biology to increase the binding with Lewis acidic groups by introducing favorable C‐F dipoles, there is virtually no experimental evidence and limited understanding of the nature of these interactions, especially their role in synthetic polymeric materials. These studies elucidate the molecular origin of inter‐ and intra‐chain interactions responsible for self‐healing of F‐containing copolymers composed of pentafluorostyrene and n‐butyl acrylate units (p(PFS/nBA). Guided by dynamic surface oscillating force (SOF) and spectroscopic measurements supported by molecular dynamics (MD) simulations, these studies show that the reformation of σ‐σ orbitals in ‐C‐F of PFS and CH3CH2‐ of nBA units enables the recovery of entropic energy via flouorophilic‐σ‐lock van der Waals forces when PFS/nBA molar ratios are ~50/50. The strength of these interactions determined experimentally for self‐healable PFS/nBA compositions is in the order ~0.3 kcal/mol which primarily comes from flouorophilic‐σ‐lock (~70%) contributions. These interactions are significantly diminished for non‐self‐healable counterparts. Strongly polarized ‐C‐F σ orbitals create lateral dipolar forces enhancing the affinity towards ‐C‐H orbitals, facilitating energetically favorable interactions. Entropic recovery driven by non‐covalent bonding offers a valuable tool in designing materials with unique functionalities, particularly self‐healable batteries or other energy storage devices.

Fluorophilic Sigma(σ)-Lock Self-Healable Copolymers.

Although F-containing molecules and macromolecules are often used in molecular biology to increase the binding with Lewis acidic groups by introducing favorable C-F dipoles, there is virtually no experimental evidence and limited understanding of the nature of these interactions, especially their role in synthetic polymeric materials. These studies elucidate the molecular origin of inter- and intra-chain interactions responsible for self-healing of F-containing copolymers composed of pentafluorostyrene and n-butyl acrylate units (p(PFS/nBA). Guided by dynamic surface oscillating force (SOF) and spectroscopic measurements supported by molecular dynamics (MD) simulations, these studies show that the reformation ofσ-σorbitals in -C-F of PFS and CH3CH2- of nBA units enables the recovery of entropic energy viaflouorophilic-σ-lockvan der Waals forces when PFS/nBA molar ratios are ~50/50. The strength of these interactions determined experimentally for self-healable PFS/nBA compositions is in the order ~0.3 kcal/mol which primarily comes fromflouorophilic-σ-lock(~70%) contributions. These interactions are significantly diminished for non-self-healable counterparts. Strongly polarized -C-Fσorbitals create lateral dipolar forces enhancing the affinity towards -C-H orbitals, facilitating energetically favorable interactions. Entropic recovery driven by non-covalent bonding offers a valuable tool in designing materials with unique functionalities, particularly self-healable batteries or otherenergy storage devices.

Net zero energy analysis and energy conversion of sustainable residential building in Muscat, Oman

The building sector is the predominant consumer of primary energy globally. The building sector accounts for around 40% of global energy production.Net Zero Energy Buildings (NZEBs) are highly suggested by energy experts as an effective option to alleviate the strain on primary energy sources caused by the building sector. The disparity between energy performance predictions provided during the design phase and the actual energy performance of residential buildings is mostly attributed to a limited comprehension of the components that influence energy consumption and the constraints of whole building simulation software. The objective of this research was to perform a comparison analysis of the expected and actual energy consumption of a prototype net-zero energy house built at the University of Technology and Applied Sciences in Muscat. The Hourly Analysis Programme (HAP V4.2) was utilised to forecast the energy consumption of a Net Zero Energy Building (NZEB) at HCT, taking into account the availability of an Energy Recovery Ventilator (ERV) and the absence of an ERV. The newly built house underwent a one-month testing phase to fulfil many duties according to competition regulations. One of the main goals was to generate on-site energy through photovoltaic panels, producing an amount proportional to the energy consumed by the house. Upon comparing the actual energy consumption data with the simulated result, it was noticed that the actual energy demand of the house was around 20% lower than the prediction made by the simulation tool.

Insights into PVC-promoted hydrothermal carbonization of manure: Dechlorination, inorganic metals removal, and combustion behaviors

Hydrothermal carbonization (HTC) can serve as a promising route to effectively co-valorize biomass and plastic wastes for solid fuel production. However, manure-derived hydrochar for fuel application remains a significant challenge due to its high ash content and low energy density. Polyvinyl chloride (PVC), as a chlorine-containing plastic, subjected to HTC commonly results in the generation of massive acidic wastewater. Herein, we proposed a PVC-promoted HTC route for high energy–density hydrochar production. By utilizing PVC as an in situ acidic additive, the HTC condition was optimized at 275 °C, 30 min, with a PVC addition of 10 %. The hydrochar obtained under the optimized condition exhibited a higher heating value (HHV) of 25.89 MJ/kg, comparable to bituminous coals, and achieve a high energy recovery rate of nearly 70 %. Moreover, the excellent removal efficiencies of inorganic metals and chlorine both exceeding 95 % (except for Fe at 86 %) were observed, owing to the strong interactions between dechlorination and inorganic metals removal. Importantly, it was evidenced that acidic reaction environment was demonstrated to enhance the carbonization degree and modify the hydrochar formation mechanism. Furthermore, the high comprehensive combustion index S of 3.22 × 10−7 %2/( °C3·min2) and low average Ea of 134.20 kJ/mol were achieved, indicating the favorable combustion behaviors. Overall, this work systematically and comprehensively investigated the PVC-promoted HTC of manure waste for advanced solid fuel production and examined its combustion characteristics, unveiling the hydrochar formation mechanism.

Ionic liquid catalyzed low-temperature hydrothermal carbonization of sewage sludge to produce hydrochar with low heavy metal content and positive energy recovery

An ionic liquid (IL, [DMAPA]HSO4) was prepared to facilitate the removal of heavy metals by hydrothermal carbonization (HTC) in sewage sludge (SS) and to obtain a positive energy recovery (ER, (Energyoutput/Energyinput − 1) > 0). The results found that the removal efficiencies of the Fe, Mn, Zn, Co, and Cd from SS exceeded 75 % with positive ER (6 %) at 20 wt% IL dosage (IL:SS). IL promoted the HTC reactions of proteins and polysaccharides to produce fixed carbon and small molecule polymers. The process mainly relies on IL to catalyze the dehydration and graphitization of SS and to destroy the heavy metal binding sites such as carboxyl and hydroxyl groups. Additionally, IL aids in constructing the macropore structures in hydrochar, thereby facilitating the release of heavy metals and water during the HTC process. This discovery holds promise for removing heavy metals from SS by one-pot HTC processes with positive energy recovery.

Removal of silica in rice husk derived Ni/biochar modifies reaction intermediates formed and minimizes coking in steam reforming of glycerol

Metal/biochar catalyst features with the advantages for easy recovery of chemical energy of biochar carrier and metal species via simply combustion. Another unique feature of biochar carrier is intrinsic inorganic species, which might also interact with metal species in resulting catalyst. This was investigated herein by synthesis of the Ni/biochar with rice husk-derived biochar carrier pretreated with NaOH for removal of SiO2 and evaluation of the resulting catalysts in steam reforming of glycerol. The solid phase reactions between NaOH and biochar (mass ratio: 2) plus subsequent washing removed 94.6% of ash (mainly SiO2). This formed Ni/biochar of fragmented surface with specific surface area increasing from 207.8 to 457.4 m2g-1 and simultaneously increasing mesopore percentage from 15.5% to 24.0%. NaOH treatment also effectively removed significant portion of both Lewis and Brønsted acidic sites but created abundant alkaline sites. These drastically enhanced nickel dispersion and activity for steam reforming. In-situ IR characterization suggested enhanced adsorption/activation of CO2 and H2O over Ni/biochar treated with NaOH (Ni/biochar-NaOH), which mitigated accumulation of coke precursors bearing CO or CC via accelerated gasification reactions. This led to the reduced amount of coke (mass ratio to catalyst) from 193.4% to 94.7% over Ni/biochar treated with 2-fold of NaOH or to 111.3% over Ni/biochar treated with 1-fold of NaOH. The coke formed was mainly catalytic type in form of carbon nanotube over Ni/biochar-NaOH. The superior resistivity to coking originated from developed pores, enhanced Ni dispersion and abundant alkaline sites from the NaOH treatment.

The determinants of municipal solid waste management efficiency in EU countries

The main purpose of this paper is to assess the municipal solid waste management (MSWM) efficiency of European Union countries and to identify the determinants of this efficiency before and after introducing Directive (EU) 2018/851. The research was conducted for 23 EU Member States in order to analyse the two highest-priority waste treatment methods (material recycling and energy recovery) and the level of greenhouse gases emitted by the waste management sector. The data for 2015-2020 were extracted from the Eurostat database. The period of data was divided into two sub-periods: 2015-2017 (the period before introducing the Directive) and 2018-2020. MSWM efficiency scores were calculated using the DEA method. Later, the Tobit Regression Model (TRM) was applied to identify the determinants. The efficiency analysis showed that the countries which joined the EU before 2000 improved their MSWM efficiency in 2018-2020 compared with 2015-2017. On the other hand, the average efficiency scores of the countries that joined the EU after 2000 decreased. In 2015-2017, the following determinants of MSWM efficiency occurred to be statistically significant: population density, unemployment rate, the number of patents and the tourism intensity index, while in 2018-2020: population density, unemployment rate, Research & Development (R&D) expenditure, higher education proportion and MSW generated. A detailed analysis of these variables showed that the countries that joined the EU after 2000 should first increase their R&D expenditure and support their inhabitants in increasing their educational level.

Dynamics of seaweed-inspired piezoelectric plates for energy harvesting from oscillatory cross flow

Inspired by the vibrations of aquatic plants such as seaweed in the unsteady flow fields generated by free-surface waves, we investigate a novel device based on piezoelectric plates to harvest energy from oscillatory cross flows. Towards this end, numerical studies are conducted using a flow-structure-electric interaction model to understand the underlying physical mechanisms involved in the dynamics and energy harvesting performance of one or a pair of piezoelectric plates in an oscillatory cross flow. In a single-plate configuration, both periodic and irregular responses have been observed depending on parameters such as normalized plate stiffness and Keulegan–Carpenter number. Large power harvesting is achieved with the excitation of natural modes. Besides, when the time scale of the motion and the intrinsic time scale of the circuit are close to each other the power extraction is enhanced. In a two-plate configuration with tandem formation, the hydrodynamic interaction between the two plates can induce irregularity in the response. In terms of energy harvesting, two counteracting mechanisms have been identified, shielding and energy recovery. The shielding effect reduces plate motion and energy harvesting, whereas with the energy recovery effect one plate is able to recovery energy from the wake of another for performance enhancement. The competition between these mechanisms leads to constructive or destructive interactions between the two plates. These results suggest that for better performance the system should be excited at its natural period, which should be close to the intrinsic time scale of the circuit. Moreover, using a pair of plates in a tandem formation can further improve the energy harvesting capacity when conditions for constructive interaction are satisfied.