Energy Balance Analysis Research Articles

Energy efficiency for wine companies: Regional sustainability initiatives in the Guadalupe valley from a transdisciplinary perspective

Energy efficiency is an aspect highly related to the sustainability and competitiveness in the medium and long term of any company. This paper describes the theoretical and technical generalities of some case studies related to wine-producing companies located in the Guadalupe Valley, Mexico, which began the implementation of an energy management system based on ISO 50001 to optimize the use of energy and minimize the carbon footprint of its products (wine). The framework for these Capstone Projects and the multi-year energy balance analysis using Sankey diagrams are presented to determine the Energy Performance Indicators and Significant Energy Uses. In addition, considering the experiences gained in these projects, a transdisciplinary analysis is carried out to strengthen the sustainable life cycle of the wine based on resource efficiency as the main element from a circular economy approach.

Determining Optimal Temperature Combination for Effective Pretreatment and Anaerobic Digestion of Corn Stalk.

Temperature is one of the important factors affecting both chemical pretreatment and anaerobic digestion (AD) process of corn stalk (CS). In this work, the combined ways between pretreatment temperature (40 °C and 60 °C) and AD temperature (35 °C and 55 °C) were selected to investigate the AD performance for sodium hydroxide (NaOH) pretreated CS. Three organic loading rates (OLRs) of 1.6, 1.8 and 2.0 g·L−1·d−1 were studied within 255 days using continuously stirred tank reactors (CSTR). The results revealed that biogas yields of CS after pretreated were higher than that of untreated groups by 36.79–55.93% and 11.49–32.35%, respectively. When the temperature of NaOH pretreatment changed from 40 °C to 60 °C, there was no significant difference in enhancing the methane yields during the three OLRs. The mesophilic AD (MAD) of CS pretreated with 2% NaOH under 40 °C and 60 °C conditions produced 275 and 280 mL·gvs−1 methane yield at OLR of 1.6 g·L−1·d−1. However, as the OLR increased, the methane yield of CS under thermophilic AD (TAD) condition was further higher than under MAD condition. Furthermore, from the perspectives of energy balance and economic analysis, AD of 40 °C-treated CS recovered more energy and TAD is less expensive. Therefore, temperature of 40 °C was considered as an appropriate for pretreatment whether in mesophilic or thermophilic AD system. On the other hand, TAD was chosen as the optimal AD temperatures for higher OLRs.

Study the effect of different operation parameters on the reaction shaft performance of a copper flash smelting furnace: Mass and energy balance analysis

Mass and energy balance analysis is one of the classical methods of modeling applied in the flash furnace smelting process. This method is an efficient method for degrading the theoretical parameters of silica flux and air required for oxidation processes. In this study, the reaction shaft of the Sarcheshmeh flash smelting furnace has been modeled using the mass and energy balance method. A modeling code has been developed to calculate the oxygen content required for oxidation processes and the silica flux for slagging. Different parameters are effective in the working conditions of the flash smelting furnace. In this research, the effect of concentrate mineralogical analysis, oxygen enrichment, flue dust share, and the amount of natural gas was investigated. The modeling results show that by increasing chalcocite in the feed mixture, the average temperature in the reaction shaft will decrease. Increasing the oxygen enrichment increases the temperature and reduces the amount of off-gases that leave the furnace. The calculation can be repeated via modeling from different modes until improved furnace conditions are achieved and smelting operation is controlled.

Feasibility assessment of biogas production from the anaerobic co-digestion of cheese whey, grease interceptor waste and pulped food waste for WRRF

This study investigates the impact of co-digestion of waste activated sludge (WAS) and primary sludge (PS) with cheese whey (CW), grease interceptor (GI) waste, and pulped food waste (PFW) using lab-scale mesophilic anaerobic digesters (AD) and bench-scale biogas potential assays. The addition of CW (20% v/v) and GI waste (10% v/v) with PS resulted in the increase of biogas productions (methane) by 15% and 2%, respectively compared to PS digestion only. The corresponding VS removal increased by 92% and 5% for CW and GI waste addition, respectively. Results from biogas potential assay experiments indicated that CW co-digestion with PS did not improve biogas productions but GI waste and PFW have the potential for improved biogas productions when mixed with PS. The experimental data were further used for detailed energy balance analysis of a water resource recovery facility (WRRF) to understand the influence of co-digestion on energy neutrality.

Submerged anaerobic membrane bioreactor applied for mainstream municipal wastewater treatment at a low temperature: Sludge yield, energy balance and membrane filtration behaviors

The anaerobic membrane bioreactor (AnMBR) has potential as a low-cost wastewater treatment process with the benefit of energy production. However, to ensure satisfactory treatment performance, an AnMBR is operated at a relatively high temperature currently. Research focused on the operation of the AnMBR at low temperature is significant since the energy required for heating is an impediment to the application of AnMBRs for municipal wastewater treatment. Hence, in this study, a constant low-temperature (15 °C) AnMBR was evaluated for the treatment of real municipal wastewater with hydraulic retention times (HRTs) in the range of 6–24 h. During the long-term experiment, a chemical oxygen demand (COD) removal efficiency of approximately 90.5% was obtained with a sludge yield below 0.13 g-VSS/g-CODrem at HRTs of 16 and 24 h. The amount of energy generated was theoretically calculated based on biogas production, with a high of 0.62 kWh/t. The energy balance analysis showed that the AnMBR process can be energy positive under the optimal operational conditions investigated. Membrane filtration performed well during operation at 15 °C with HRTs ranging between 12 and 24 h, while it was compromised at the extremely short HRT of 6 h. In this study, the effectiveness of optimizing the conditions on the performance of the AnMBR operating at low temperature was confirmed, along with the potential for energy recoverability under those conditions.

Diurnal Surface Heating and Roof Material Effects on Urban Pollution Dispersion: A Coupled Large-eddy Simulation and Surface Energy Balance Analysis

Diurnal Surface Heating and Roof Material Effects on Urban Pollution Dispersion: A Coupled Large-eddy Simulation and Surface Energy Balance Analysis

Comparison of Two Analytic Energy Balance Models Shows Stable Partial Ice Cover Possible for Any Obliquity

Abstract In this study, we compare two analytic energy balance models with an explicit dependence on obliquity to study the likelihood of different stable ice configurations. We compare the results of models with different methods of heat transport and different insolation distributions. We show that stable partial ice cover is possible for any obliquity, provided the insolation distribution is sufficiently accurate. Additionally, we quantify the severity of the transition to the snowball state as different model parameters are varied. In accordance with an earlier study, transitions to the snowball state are more severe for higher values of the albedo contrast and energy transport across latitudes in both models; however, we find that the snowball transition is not equally likely across both models. This work is general enough to apply to any rapidly rotating planet and could be used to study the likelihood of snowball transitions on planets within the habitable region of other stars.

Interfacial adhesion assessment of SiN/GaAs film/substrate system using microcantilever bending technique

In this study, a microcantilever bending technique was applied to evaluate the interfacial adhesion of a silicon nitride (SiN) film on a gallium arsenide (GaAs) substrate. Miniaturised cantilevers in micrometre scale were machined on the SiN/GaAs cross-section using focused ion beam milling. Subsequent bending tests was performed on a nanomechanical testing system. Static and cyclic loadings were applied to bend the cantilevers until they fractured. All cantilevers failed at the SiN/GaAs interface. A finite element analysis (FEA) model was used to simulate the deflection of the cantilevers and the stress state at the locus of failure was analysed. Interfacial fracture strength σ in was derived from the FEA model. The mean values of σ in from the static and cyclic loading tests were 0.8 ± 0.2 and 0.5 ± 0.1 GPa, respectively. An energy balance analysis was then used to evaluate an interfacial toughness of G in = 0.18 ± 0.05 J m−2.

Energy transfer analysis of the SH626 sheet rotary dryer on the production system perspective

The energy transfer process occurred at all stages of the production system and could demonstrate potential changes in the state of the system during production. The cut tobacco production process also would require a large amount of heat energy to make a high-quality product. Based on the energy balance analysis of the SH626 dryer, the energy consumption of the tobacco drying process was the highest unit, which accounts for approximately 60% of the energy consumption of the whole tobacco production process. The energy transfer efficiency of the sheet heating system was only 0.46 ∼ 0.58 and was mainly influenced by the working temperature of thin plates. The energy transfer efficiency of the hot air heating system was 0.24 ∼ 0.33 and was influenced by the hot air mass flow rate. The energy transfer system remained low levels of energy transfer efficiency and had great potential for saving energy. Those conclusions of this study could provide a theoretical basis to improve dryer system energy transfer efficiency by the thermal integrated system and the intelligent control system.

Assessment of the impact of the kinetic effect of ion parallel heat conduction on DEMO-relevant SOL plasma using integrated SOL-divertor code SONIC

In plasmas of lower collisionality, such as the scrape-off layer (SOL) of a fusion tokamak device, the parallel heat conductivity of ions becomes smaller than the classical Spitzer–Harm model due to a nonlocal kinetic effect. We have assessed, by simulation, the impact and role of the kinetic effect of ion heat conductivity (abbreviated as ion KE in this paper) on DEMO-relevant tokamak SOL plasma, using the Japanese demonstration tokamak reactor concept JA DEMO. A series of test simulations, where the ion KE is modeled by a widely used free-streaming energy (FSE)-limited model, has demonstrated: (a) the ion KE decreases the ion parallel heat flux density in JA DEMO SOL (at the baseline operation scenario) around the X-point and further upstream of the low-field side (LFS) area along the separatrix, where the parallel collisionality is smaller. Up to 40%–60% decrease is observed, compared to the case without (w/o) ion KE, among the test cases where the ion KE level is scanned over the possible range (i.e. parameter α i of the FSE-limited model is varied over ); (b) the ion KE leads to significant increase in the ion temperature T i (up to 600% increase) and significant decrease in the ion density n i (up to −80%) over wide area of the SOL upstream. Energy balance analysis has suggested that the ion KE affects the upstream n i and T i by the power of 0.4 and −0.4, respectively, of the flux limiting factor, as long as spatial changes in plasma parameters are moderate. The results of this study serve as a fundamental assessment of the ion KE for DEMO- relevant SOL plasma, clarifying the need for further sophistication of the model toward more quantitative prediction.

Energy balance analysis of a DI diesel engine with multiple pilot injections strategy and optimization of brake thermal efficiency

• Timing and quantity changes of two pilot injections were applied to diesel engine. • The effects of each change on total fuel energy distribution were investigated. • 2nd PiI quantity change has the strongest effect on components of total fuel energy. • 2nd PiI timing change has the least effect on components of total fuel energy. • NSGA-III optimization maximized brake thermal efficiency with an increase of 0.29%. • An increase of 0.74% was obtained in the total exhaust energy percentage which is recoverable. In this study, multiple pilot injections (MPI) strategy having two pilot injections was applied to direct injection (DI) diesel engine running at partial load which is usually within legal emission cycle. Optimization of timing and quantity of the pilot injections is a key factor in achieving performance and emission targets. Due to the advantages of pilot injections in terms of smooth and gradual release of energy from the fuel, the energy distribution in the engine has been put under scope and investigated thoroughly. The effects of varying the timing and quantity of both pilot injections within a reasonable range on brake thermal efficiency, total exhaust energy, in-cylinder heat transfer and friction were investigated and results were presented using a well calibrated and validated thermodynamic model. Relative sensitivity analysis and Spearman correlation coefficients analysis were performed to show the effects of each MPI parameter on the total fuel energy components. The variation of 2nd pilot injection quantity determined the most influential parameter on brake thermal efficiency with a relative sensitivity value of 0.4612, on in-cylinder heat transfer with a relative sensitivity value of 0.4708, on total exhaust energy with a relative sensitivity value of 0.4757 and on friction power with a relative sensitivity value of 0.4677 respectively. Similar to the variation in the 2nd pilot injection quantity, the variation in the 1st pilot injection quantity affected these responses in the same way but with less effect. Timing variations in both pilot injections were found out to be the third and the fourth parameters affecting responses. Especially the variation in 2nd pilot injection timing has the least effect on components of total fuel energy. Retarding both pilot injections increased the brake thermal efficiency and the variation of both pilot injection timing has similar effect on brake thermal efficiency. Retarding the 1st pilot injection timing augmented the total exhaust energy while reducing the in-cylinder heat transfer to coolant and friction power. Non-dominated Sorting Genetic Algorithm-III (NSGA-III) optimization tool was used for finding the optimal timing and quantity of both pilot injections to maximize brake thermal efficiency. A growth of 0.29% at a rate of %1 in the brake thermal efficiency was achieved. Additionally, an increase of 0.74% at a rate of 2.4% in the total exhaust energy has the potential to be used and recovered in the turbine.

Fabrication of Janus Liquid marbles With Tunable Particle Coverage by Controlling the Surface Tension of the Core Liquid

Janus Liquid marbles (JLMs) are next-generation liquid marbles enwrapped with multi-particles of different sizes, hydrophobicity, and/or chemical properties. The functionally distinct surface of Janus Liquid marble enables the selective and precise manipulation of liquidmarble in a controllable manner. Here, we present an efficient method to tune the particle coverage of Janus Liquid marble by controlling the surface tension of the core liquid. The impact-based fabrication strategy is used for the continuous productionof JLMs of different volumes. The tunability in particle coverage is achieved for JLMs of volumein the range 5-10 μL. A simple energy balance analysis is employed for the theoretical estimation of the maximum spread parameter (βm) and found to be in reasonableagreement with the experimentally measured value.

Hydrothermal carbonization of biomass: experimental study, energy balance, process simulation, design, and techno-economic analysis

Hydrothermal carbonization of biomass: experimental study, energy balance, process simulation, design, and techno-economic analysis

Methodological framework for wastewater treatment plants delivering expanded service: Economic tradeoffs and technological decisions

With emerging decarbonization to deploy more integrated waste management, there is a burgeoning need for re-managing waste-related infrastructures in urban environments. Wastewater treatment plants are key contributors to expanded environmental services, but relevant technological decisions and economic tradeoffs have to be assessed from a systems perspective. This study provides a methodological framework that consolidates the multiple technological and economic aspects of system retrofitting for such an evaluation purpose. Complex leachate from refuse transfer stations has been recently identified as the decarbonization roadblock of urban waste management, and it was chosen for investigations by this new methodological approach. The system impacts by complex leachate on the existing facilities were validated by experimental trials. To derive the financial outlooks for decision making, the evaluation matrix includes the quantitative impacts of bioenergy profiles, energy balance analysis of biogas utilization methods, needs of system retrofitting, economic factors, and their uncertainties. Due to the detected inefficiency of bioenergy recovery, bioinformatic analysis was proceeded for understanding the underlying mechanism to propose a mitigation solution. Overall, the methodological framework can provide a quantitative assessment of the centralized capability of wastewater treatment plants for systems planning in the new policy agenda of urban decarbonization, where the methodological potentials of expanded framework applications are also highlighted.

Energy Sustainable House: A Case study and validation through Revit

Reducing carbon footprints and adopting green energy sources is the need of modern time. Green sources of energy need to find preference over traditional sources. Unconventional sources of energy like solar, wind are alternatives of traditional energy sources. Lack of awareness, high initial investment and lack of government incentive are few challenges in adoption of green sources of energy in housing sector, especially in developing economies. Construction, design and aesthetics of traditional residential building have a significant effect on energy consumption and environment. Town planners, private housing developers and individual house owners have to become aware and adopt the non-traditional sources of energy like solar energy for meeting their daily need of energy. An energy sustainable house has minimum dependency on traditional sources of energy like coal based thermal power plants. For moving a step closer to energy sustainable building, in this research paper authors have studied the design, energy consumption and transformation of energy dependencies on roof top solar plant of a residential building by situation actor process & learning action performance (SAP-LAP) methodology. Further authors tried to validate the observations and findings of study by energy balance analysis of the same residential building by Autodesk Revit software. Studying the economical aspect of current case authors observed that the case house got 60% saving in monthly electricity bill after installing rooftop solar power plant and payback period of total investment on solar power plant is 6.5 to 7 years only.

Enzyme pretreatment of yard waste to improve anaerobic biodegradability: Modeling the interactive effects of enzyme dose, treatment temperature and treatment duration on delignification

Laccase pretreatment of yard waste (YW) was conducted for improving its anaerobic biodegradability. The optimum pretreatment condition based on response surface methodology for maximum delignification was: solid loading 19.7% (w/v) of total solid, treatment duration 9 h, and pretreatment temperature 44.5 °C. The mechanism of biomass delignification was further investigated by the change in physical and chemical properties. Specifically the increase in water retention value (2.05 times), specific porosity (1.72 times), and crystallinity index (1.25 times) in pretreated YW indicates the capability of laccase pretreatment to remove lignin selectively. The methane yield after 30 days of anaerobic digestion for untreated YW was 294 ± 12 mL/g volatile solid (VS) and for laccase pretreated yard waste at the optimum condition was 405 ± 15 mL/gVS. The Modified Gompertz model showed the best fit for untreated yard waste however for pretreated YW logistic function model was the best. The energy balance analysis of the studied method confirmed a positive energy gain of 1.6 kJ/g VS indicates further validation in field scale studies.

Response surface analysis of energy balance and optimum condition for torrefaction of corn straw

Response surface analysis of energy balance and optimum condition for torrefaction of corn straw

Raised bed planting increases economic efficiency and energy use efficiency while reducing the environmental footprint for wheat after rice production

Finding sustainable ways to produce more grain while minimizing negative environmental impacts is critical. The raised bed planting (RBP) pattern was shown to be an effective measure to enhance the productivity of wheat after rice production in areas vulnerable to waterlogging. However, comprehensive evaluations from environmental, economic and ecosystem benefit perspectives have rarely been performed. In this study, a consecutive 5-year field experiment was conducted in the Yangtze River Plain, China, with two planting patterns, flat planting (FP) and RBP, to assess the environmental footprint, energy balance and cost-benefit analysis for wheat after rice production. The results showed that the RBP pattern generated significant effects—increased grain yield, net return and energy use efficiency and a decreased carbon footprint per unit of yield/biomass—compared with the FP pattern. The advantages of the RBP pattern over the FP pattern were ascribed mainly to the 13.6% reduction in production costs, 10.1% lower energy inputs, and 10.0% reduction in indirect greenhouse gas emissions benefiting from saved machinery, diesel and seed inputs. The energy output and gross crop value for the RBP pattern were 13.3% and 15.1% higher than those for the FP pattern. Therefore, the RBP pattern reduced production costs and energy inputs but increased wheat production, energy use efficiency, and economic benefits and minimized the environmental impact. In conclusion, the RBP pattern is promising for wheat after rice cultivation from the perspective of achieving sustainable agricultural development and ensuring national food security.

Pilot-scale study on downdraft gasification of municipal solid waste with mass and energy balance analysis

The current study investigated the gasification of heterogeneous feedstock with municipal solid waste fed into a downdraft gasifier. The air from the blower for the combustion zone entered the hearth through the six nozzles. The whole combustion zone was supplied with air at a rate of 150 kg/h, based on an equivalence ratio of 0.3 to 0.5. The proposed gasifier was designed with a capacity of around 100 kg/h, and could be operated at 0.035 bar atmospheric pressure to generate product gas. The experimental findings were effectively described by a theoretical mass and energy balance. Air flow rates of 140 to 150 kg/h were used to produce good product gas quality. For 8 h, each test was run in continuous operation and steady condition. The maximum gas of 250 kg/h was generated with an equivalence ratio of 0.35 and an energy content value of 1380 kcal/Nm3. Cold gas efficiency was found to be 89.31% at an optimum equivalence ratio of 0.35. With more efficient hot gas generation from the gasifier, the cost of thermal energy using the factory's energy consumption could be significantly reduced. Although a traditional downdraft gasifier has a throat at the bottom, the adopted design had no throat and the gasification agent was supplied on the reactor downside. The heat and mass balance discrepancy of 2% between energy intake and output was minimal and could be explained by several factors not considered in the balance, such as heat loss to the environment, less tar, and unburned carbon in the ash.

Ferromanganese Production in a Submerged Arc Furnace: Thermodynamic and Energy Balance Analysis

Ferromanganese Production in a Submerged Arc Furnace: Thermodynamic and Energy Balance Analysis