Electrical Energy Recovery Research Articles

Estimation of the power of a MFC type piezoelectric used for electric energy recovery from vibrations

One of the possibilities of piezoelectric transducers applications are systems for electric energy recovering from mechanical vibrations. The obtained amount of electric energy is not big but sometimes it is enough for power supply some elements such us microcontrollers or other electronic devices with low energy consumptions. The main advantage of piezoelectric transducers used as power supply elements is that there is no necessary to replace batteries or use wires. In this paper results of laboratory tests of Macro Fiber Composite piezoelectric transducer that is used for electric energy recovering from mechanical vibrations are presented. The aim of the presented work was to estimate the maximum power of the MFC transducer that can be used as power supply for some electronic device. To do that a series of laboratory tests was done. The MFC transducer was glued on the cantilever beam surface. The beam’s vibrations were excited using the second one MFC transducer. The tested MFC transducer was electrically loaded with a voltage divider of various resistances. The generated electric voltage was measured and electric current was calculated to estimate the maximum power of the piezoelectric MFC transducer.

Effect of Temperature on Nitrogen Removal and Electricity Generation of a Dual-Chamber Microbial Fuel Cell

Microbial fuel cells (MFCs) have gained increasing attention as an effective pathway for wastewater treatment and electrical energy recovery. In this study, the pollutant removal, N2O production, and electricity generation at different temperatures (25–45 °C) in a dual-chamber MFC were investigated. The optimal temperature for pollutant removal and electricity generation was 35 °C. The results showed that maximal removal efficiencies of chemical oxygen demand (COD), ammonium (NH4+), and total nitrogen (TN) were 73.98 ± 0.92%, 99.24 ± 0.85%, and 8.28 ± 0.45%, respectively. The maximum of nitrous oxide (N2O) was 4.27 ± 0.11 mg L−1 at 35 °C. Meanwhile, the maximum of power density, current density, and coulombic efficiency (CE) were 0.54 W m−3, 6.51 A m−3, and 8.12 ± 0.04%, respectively. The results indicate that MFC is a promising technology for simultaneous pollutant removal and electricity generation in temperate regions. Moreover, microbial community analysis suggested that the dominant reaction in the cathode may include aerobic nitrification, autotrophic denitrification, heterotrophic denitrification (aerobic and anoxic), reduction of oxygen, and nitrogen fixation.

Electron donation characteristics and interplays of major volatile fatty acids from anaerobically fermented organic matters in bioelectrochemical systems

ABSTRACTAnaerobic fermentation liquid of waste organic matters (WOMs) is rich in volatile fatty acids (VFAs), which can be treated with bioelectrochemical systems for both electrical energy recovery and organics removal. In this work, four major VFAs in the fermented WOMs supernatant were selected to examine their electron donation characteristics for power output and their complicated interplays in microbial fuel cells (MFCs). Results indicated a priority sequence of acetate, propionate, n-butyrate and i-valerate when served as the sole electron donor for electricity generation. The MFC solely fed with acetate showed the highest coulombic efficiency and power density, and the longest period for electricity production. When two of the VFAs were added with equal proportion, both acids contributed positively to electricity generation, while the selective or competitive use of substrates by diverse microorganisms behaved as an antagonism effect to prolong the degradation time of each VFA. When acetate and propionate, the preferable substrates for electricity generation, were mixed in various proportions, their large concentration difference led to improved electrical performance but decreased organic removal rate.

Analysis and assessment of novel liquid air energy storage system with district heating and cooling capabilities

Integrated energy storage system is essentially proposed to achieve higher exergy recovery through the storage and the recovery of the surplus electrical energy during off-peak and on-peak hours, respectively, while producing other commodities through the charging, storing and discharging processes. The cooling is provided by the use of a solid-gas sorption cycle, which has the ability to provide the cooling effect at different temperatures. The performance of the proposed integrated energy storage system is assessed using the first and second laws of thermodynamics. The proposed system is compared to a standalone energy storage system used to store surplus electrical energy without producing other commodities, to assess whether the integration of heating and cooling production systems in the proposed storage system make sense in terms of energy and exergy. Overall energy and exergy efficiencies are 72.1% and 53.7% for the case where the cooling effect is provided at a temperature of 0 °C, for 100% conversion of the sorption chemical pair. If the cooling provided at a temperature of −35 °C, overall energy and exergy efficiencies become 67.1% and 53.7% respectively. In general, the proposed integrated system has higher energy and exergy efficiencies than the standalone system.

Carbon black as an alternative cathode material for electrical energy recovery and transfer in a microbial battery

Rather than the conventional concept of viewing conductive carbon black (CB) to be chemically inert in microbial electrochemical cells (MECs), here we confirmed the redox activity of CB for its feasibility as an electron sink in the microbial battery (MB). Acting as the cathode of a MB, the solid-state CB electrode showed the highest electron capacity equivalent of 18.58 ± 0.46 C/g for the unsintered one and the lowest capacity of 2.29 ± 0.48 C/g for the one sintered under 100% N2 atmosphere. The capacity vibrations of CBs were strongly in coincidence with the abundances of C=O moiety caused by different pretreatments and it implied one plausible mechanism based on CB’s surface functionality for its electron capturing. Once subjected to electron saturation, CB could be completely regenerated by different strategies in terms of electrochemical discharging or donating electrons to biologically-catalyzed nitrate reduction. Surface characterization also revealed that CB’s regeneration fully depended on the reversible shift of C=O moiety, further confirming the functionality-based mechanism for CB’s feasibility as the role of MB’s cathode. Moreover, resilience tests demonstrated that CB cathode was robust for the multi-cycles charging-discharging operations. These results imply that CB is a promising alternative material for the solid-state cathode in MBs.

Prototype of a scaled-up microbial fuel cell for copper recovery.

BackgroundBioelectrochemical systems (BESs) enable recovery of electrical energy through oxidation of a wide range of substrates at an anode and simultaneous recovery of metals at a cathode. Scale‐up of BESs from the laboratory to pilot scale is a challenging step in the development of the process, and there are only a few successful experiences to build on. This paper presents a prototype BES for the recovery of copper.ResultsThe cell design presented here had removable electrodes, similar to those in electroplating baths. The anode and cathode in this design could be replaced independently. The prototype bioelectrochemical cell consisted of an 835 cm2 bioanode fed with acetate, and a 700 cm2 cathode fed with copper. A current density of 1.2 A/−2 was achieved with 48 mW m−2 of power production. The contribution of each component (anode, electrolytes, cathode and membrane) was evaluated through the analysis of the internal resistance distribution. This revealed that major losses occurred at the anode, and that the design with removable electrodes results in higher internal resistance compared with other systems. To further assess the practical applicability of BES for copper recovery, an economic evaluation was performed.ConclusionAnalysis shows that the internal resistance of several lab‐scale BESs is already sufficiently low to make the system economic, while the internal resistance for scaled‐up systems still needs to be improved considerably to become economically applicable.© 2017 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Microbial fuel cell with high content solid wastes as substrates: a review

With the increasing concern about the serious global energy crisis and high energy consumption during high content solid wastes (HCSWs) treatment, microbial fuel cell (MFC) has been recognized as a promising resource utilization approach for HCSW stabilization with simultaneous electrical energy recovery. In contrast to the conventional HCSW stabilization processes, MFC has its unique advantages such as direct bio-energy conversion in a single step and mild reaction conditions (viz., ambient temperature, normal pressure, and neutral pH). This review mainly introduces some important aspects of electricity generation from HCSWand its stabilization in MFC, focusing on: (1) MFCs with different fundamentals and configurations designed and constructed to produce electricity from HCSW; (2) performance of wastes degradation and electricity generation; (3) prospect and deficiency posed by MFCs with HCSWas substrates. To date, the major drawback of MFCs fueled by HCSW is the lower power output than those using simple substrates. HCSW hydrolysis and decomposition would be a major tool to improve the performance of MFCs. The optimization of parameters is needed to push the progress of MFCs with HCSW as fuel.

Development of portable measuring system for testing of electrical vehicle's heat energy recovery system

Nowadays the consumer society applies a huge amount of energy in many fields including transportation sector. Internal combustion vehicles contribute substantially to the air pollution. An alternative solution for reducing energy consumption is replacing the internal combustion vehicles by electrical or hybrid vehicles. Today one of the biggest disadvantages of the electrical vehicles is the finite capacity of batteries. The research topic presented in this paper is the „Energy Harvesting”, and development of energy recovery system for electrical vehicles which largely contributes in increasing the driving range. At the current phase of the research efficiency analysis of the heat energy recovery devices are investigated in real driving circumstances. Computer based mobile and wireless measurement system for the analysis was developed, tested and installed in a real vehicle. Driving tests were performed and analysed in different circumstances.

Characteristics of the energy regeneration and reutilization system during the acceleration stage of the swing process of a hydraulic excavator

Although the traditional energy regeneration system which uses electric or hydraulic energy recovery to regenerate part of the overflow energy loss during the acceleration and braking stages of the swing process of a hydraulic excavator, the modification cost is high and the control system is complex. To reduce the overflow energy loss of the swing process of the hydraulic excavator and to simplify the control system, a novel swing driving system based on a hydraulic accumulator to regenerate and utilize the energy automatically during the acceleration process is presented. The working mode and the assessment criteria of the swing system are analysed. The characteristics of the traditional swing system and the proposed swing system are compared. The relationships between the pressures of the two motor chambers, the pressures of the hydraulic accumulator and the motor speed of the proposed swing system in one working cycle are studied. The experimental results showed that the energy recovery efficiency of the proposed swing driving system, which can regenerate the energy automatically based on the hydraulic accumulator, was up to 80% during the acceleration stage of the swing process, and the energy consumption of the power system in one working cycle was reduced by 16.5% in comparaison with that of the traditional driving system.

Glycerol-fed microbial fuel cell with a co-culture of Shewanella oneidensis MR-1 and Klebsiella pneumonae J2B.

Glycerol is an attractive feedstock for bioenergy and bioconversion processes but its use in microbial fuel cells (MFCs) for electrical energy recovery has not been investigated extensively. This study compared the glycerol uptake and electricity generation of a co-culture of Shewanella oneidensis MR-1 and Klebsiella pneumonia J2B in a MFC with that of a single species inoculated counterpart. Glycerol was metabolized successfully in the co-culture MFC (MFC-J&M) with simultaneous electricity production but it was not utilized in the MR-1 only MFC (MFC-M). A current density of 10mA/m(2) was obtained while acidic byproducts (lactate and acetate) were consumed in the co-culture MFC, whereas they are accumulated in the J2B-only MFC (MFC-J). MR-1 was distributed mainly on the electrodein MFC-J&M, whereas most of the J2B was observed in the suspension in the MFC-J reactor, indicating that the co-culture of both strains provides an ecological driving force for glycerol utilization using the electrode as an electron acceptor. This suggests that a co-culture MFC can be applied to electrical energy recovery from glycerol, which was previously known as a refractory substrate in a bioelectrochemical system.

Kinetic energy recovery systems in motor vehicles

The article draws attention to the increasing environmental pollution caused by the development of vehicle transport and motorization. Different types of design solutions used in vehicles for the reduction of fuel consumption, and thereby emission of toxic gasses into the atmosphere, were specified. Historical design solutions concerning energy recovery devices in mechanical vehicles which used flywheels to accumulate kinetic energy were shown. Developmental tendencies in the area of vehicle manufacturing in the form of hybrid electric and electric devices were discussed. Furthermore, designs of energy recovery devices with electrical energy storage from the vehicle braking and shock absorbing systems were presented. A mechanical energy storing device using a flywheel operating under vacuum was presented, as were advantages and disadvantages of both systems, the limitations they impose on individual constructions and safety issues. The paper also discusses a design concept of an energy recovery device in mechanical vehicles which uses torsion springs as the main components of energy accumulation during braking. The desirability of a cooperation of both the mechanical- and electrical energy recovery devices was indicated.

A Thermally-Regenerative Ammonia-Based Flow Battery for Electrical Energy Recovery from Waste Heat.

Large amounts of low-grade waste heat (temperatures <130 °C) are released during many industrial, geothermal, and solar-based processes. Using thermally-regenerative ammonia solutions, low-grade thermal energy can be converted to electricity in battery systems. To improve reactor efficiency, a compact, ammonia-based flow battery (AFB) was developed and tested at different solution concentrations, flow rates, cell pairs, and circuit connections. The AFB achieved a maximum power density of 45 W m(-2) (15 kW m(-3) ) and an energy density of 1260 Wh manolyte (-3) , with a thermal energy efficiency of 0.7 % (5 % relative to the Carnot efficiency). The power and energy densities of the AFB were greater than those previously reported for thermoelectrochemical and salinity-gradient technologies, and the voltage or current could be increased using stacked cells. These results demonstrated that an ammonia-based flow battery is a promising technology to convert low-grade thermal energy to electricity.

A sandwiched denitrifying biocathode in a microbial fuel cell for electricity generation and waste minimization

A denitrifying biocathode in a microbial fuel cell was developed to investigate the replacement of the costly Pt-coated abiotic cathodes for electricity generation. The denitrifying biocathode was sandwiched between the dual-anode systems. The study investigated the performance for simultaneous treatment of wastewater on the anode, biological denitrification on the cathode and the potential recovery of electrical energy. Autotrophic biofilms performed denitrification on the cathode using supplied electrons by the biodegradation of organics on the anode. Graphite granules were used as electrodes for biofilm attachment, and nafion membranes were used as separators between electrodes. The system achieved a volumetric power of 7 ± 0.4 W m−3 net cathodic compartment (NCC) with the simultaneous removal of 229.5 ± 18 mg L−1 COD on anode and 88.9 g m−3 NCC day−1 nitrogen on cathode, respectively. The columbic efficiency for cathodic and anodic reactions was 98.9 ± 0.57 and 23.54 ± 0.87 %, respectively. This is a combined study for domestic wastewater treatment and biological denitrification in a compact MFC reactor. Further optimization of the system is desired to improve its performance and applicability.

GASTONE – Development of a New Powertrain Concept Based on the Integration of Electric Generation, Energy Recovery and Storage

The new challenge in the reduction of CO2 emissions by heavy duty trucks is leading to a technological evolution in powertrain efficiency.Towards this objective, the EU has funded in the frame of the 7th framework program the project GASTONE: a collaborative project between several private and public companies and institutions: CRF, FTP, Continental, GENTHERM, MAGNA and U. Politécnica de Valencia, targeting the development of a new powertrain concept based on the integration of electric generation, energy recovery and storage with engine system and control strategies.The main features of this CNG engine concept are:•The energy recovery from the exhaust gases heat with a cascade approach thanks to the adoption of an advanced thermoelectric generator and a turbo-generator.•The integration of a smart kinetic energy recovery system to substitute the alternator with a smarter electrical machine.•The electrification of the main auxiliaries (coolant and oil pumps, auxiliary e-supercharger and air conditioning compressor).The electrification process is supported by an improvement of the performance of the CNG engine (the actual average value is about 38%): this number is expected to rise by 4% thanks to the engine control strategy improvement, by 1% due to the introduction of the water charge air cooler, by 2% from the reduction of the belt drive and gear losses, by 1% from the system strategy and management optimization and by 7% from the exhaust heat recovery (thermo-electric generator plus turbo-generator).This paper presents the details of the new powertrain concept design, the simulation tool developed to support the design and optimize the system and a cost per function tool to perform an economic analysis in the hypothesis to introduce the system in the market.The obtained benefits are expressed in terms of fuel saving for a target real driving cycle and effects related to the new devices are developed and tested.The project is in the design phase and the paper collects a first estimation of results based on the design, strategy and control improvement.

Evaluation of greenhouse gas emissions for several municipal solid waste management strategies

Burgeoning of municipal solid waste treatment issues and concerns on climate change have drawn massive attention. The Taiwanese Government is taking a concerted effort to voluntarily reduce greenhouse gas emissions to meet global warming protocols. This study evaluated the greenhouse gas emissions from five municipal solid waste treatment scenarios, including landfilling, waste to energy, and material recovery. The findings from this study indicate that a material recovery facility (8.08 × 103 to 1.52 × 104 kg CO2-eq/day) or a landfill site (4.45 × 103 to 4.45 × 104 kg CO2-eq/day) emits less greenhouse gases than a waste to energy plant (1.10 × 106 to 4.39 × 106 kg CO2-eq/day) for handling 20,000 tonne/day of municipal solid waste. The greenhouse gas emissions from a waste to energy plant are mainly carbon dioxide and nitrous oxide, but can be offset by electricity generation and energy recovery. Furthermore, potential of greenhouse gas mitigation from waste recycling in a material recovery facility can be more effective than electricity generation in a waste to energy plant. This study provides valuable insights into the applicability of a policy framework for municipal solid waste management practices with regards to reduction of greenhouse gas emissions.

Life cycle assessment of lignite pyrolysis: a case study in China

In this study, a life cycle assessment was conducted using the ReCiPe method to estimate the environmental impact of lignite pyrolysis, which is one of the most commonly used technologies for lignite upgrading. Technological advancements significantly affect climate change, human health, and fossil depletion. The influence of lignite pyrolysis on the effect of other categories on the environment was small. Improved efficiency in electricity consumption and energy (i.e., steam and electricity) recovery from oven gas, optimized transportation (i.e., type and distance), and lignite drying technologies, as well as decreased levels of mined lignite and direct air emissions (e.g., heavy metals, benzene, and carbon dioxide) from the lignite pyrolysis stage, are the key factors in reducing the overall environmental impact of lignite pyrolysis.

Case study of an MBT plant producing SRF for cement kiln co-combustion, coupled with a bioreactor landfill for process residues

The paper describes the performances of the energy recovery pathway from the residual waste based on the production of a Solid Recovered Fuel (SRF) to be exploited via co-combustion in a cement kiln. The SRF is produced in a single stream Mechanical–Biological Treatment plant, where bio-drying of the waste is followed by mechanical refining in order to fulfil the quality requirements by the cement kilns. Peculiar of this MBT is the fact that sorting residues are disposed in a nearby landfill, managed according to a bioreactor approach, where landfill gas is collected for electric energy recovery. A detailed mass and energy balance of the system is presented based on one year operational data, followed by its Life Cycle Assessment. Results show that the system is energetically and environmentally effective, with most of the impacts being more than compensated by the savings of materials and energy. Major role in determining such outcome is the displacement of petcoke in the cement kiln, both in terms of its fossil CO2 emissions and of its life cycle impacts, including the trans-oceanic transport. To check the robustness of the results, two sensitivity analyses are performed on the landfill gas collection efficiency and on the avoided electric energy mix.

Production of waste energy and heat in hospital facilities

Highly efficient utilization of the energy potential of waste is a crucial matter in the process of thermal conversion. A vast majority of research studies published to this date on electrical energy and heat recovery have been concerned with large MSW (municipal solid waste) incineration systems. Only few of the publications presented the research on electrical energy and heat recovery in small and medium incinerating plants. They were focused on the production of syngas (waste gasification) and its combustion in gas engines. The research studies described in the article included electrical energy and heat recovery from the medical waste incineration installation with the efficiency of 220 kg/h. The research was carried out in a large hospital facility. The tested installation consisted of three basic elements: HSRG (heat recovery steam generator), MT (microturbine) producing electrical energy and steam/water heat exchanger. The efficiency values of individual units were high: HRSG–78%, MT-79% and HT-99%. The total disposable enthalpy flux of steam entering the turbine was low and it was not possible to produce a sufficient amount of electricity. The average electrical energy flux produced during the tests amounted to Ėue-MT = 31.6 kWe, which constituted 4.2% of the total flux of usable energy recovered by the installation. The rest was the enthalpy flux of hot water – Ėue-HE = 729 kW (95.8%). Such installations can be used, provided that there are systems that are capable of receiving that type of heat throughout the entire calendar year. It was proven that the experimental installation had small impact on the environment. The SPB (simple payback period) of the investment expenditures incurred in order to complete the installation amounted to 3.1 years.

Use of low cost and easily regenerated Prussian Blue cathodes for efficient electrical energy recovery in a microbial battery

A microbial battery (MB) equipped with a Prussian Blue (PB) cathode is reported.

Study of the efficiency of the electric energy recovery process in the subway

Experimental research of qualitative efficiency indicators of the electric energy recovery process in the subway was carried out in the paper. It was found that in Dnipropetrovsk Metro there is a significant untapped reserve of energy-saving from the electric energy recovery in the range of 15...50% of energy expenditure for train operation. However, train traffic volumes, strongly variable nature of tractive electric energy consumption and lack of regenerative braking system in subway trains do not allow to realize this potential today. The prospect of buying new and upgrading existing cars requires prior research of efficiency indicators of regenerative energy from braking of trains in the subway. As a result of the study, it was found that the energy, generated by electric trains while electric braking has intermittent nature (8...20 seconds) with decreasing power and contains a considerable variable component (30...50%). Taking into account these indicators is relevant when selecting measures for the effective use of excess regenerative energy in subway trains since the return of unstabilized energy with such parameters to the primary energy system may make significant distortions and negatively affect operation of nontractive consumers.