Environmental Impact Of System Research Articles

A comprehensive 6E analysis of a novel multigeneration system powered by solar-biomass energies

This study presents a novel multigeneration system comprising five different cycles driven by a combination of solar and biomass energy resources. This system includes a modified gas turbine cycle, a trans-critical CO2 cycle (TCO2), a steam Rankine cycle, a biomass-fueled boiler, and a solar collector. The gas turbines exhibit limited thermal efficiency, primarily due to substantial heat losses. Consequently, the TCO2 cycle and the steam Rankine cycle are integrated into the system to improve performance. An innovative aspect of this study is the utilization of a unique configuration of transcritical CO2 and steam Rankine cycles, combined with biomass and solar energies, aimed at maximizing energy recovery and minimizing waste. Furthermore, a proton membrane electrolyzer (PEME) is integrated into the system for hydrogen production, along with a proton membrane fuel cell (PEMFC) to increase electricity generation. In this comprehensive analysis, in addition to energy and exergy analyses, exergoeconomic, exergoenvironmental, emergoeconomic, and emergoenvironmental analyses are conducted. The results indicate that the proposed system achieves notable energy and exergy efficiencies of 20.2 % and 15.2 %, respectively. The total investment cost rate for the system equipment is 0.007554 $/s and the system's environmental impact is 0.0008611 pt/s. The results of the emergy analysis reveal that the emergoeconomic values of the streams are lower than the corresponding environmental values, primarily due to the higher environmental impact throughout the components' life cycle compared to their economic value.

Exergy analysis and Exergetic sustainability index of package boiler

Energy is one of the basic human needs. Economic growth and population growth in a country which continues to increase is directly proportional to the growth in energy needs required by society. Indonesia is the largest energy user in Southeast Asia, namely more than 36% of Southeast Asia's primary energy use. Utilization of the energy used will reduce the increase in production costs for an industry. The use of energy is better known as energy conservation. Energy and exergy analysis based on the first and second laws of thermodynamics is used to analyze the thermal system of industrial units. This can be applied to equipment units in the fertilizer industry to identify sources of inefficiency, determine their location and the amount of exergy destruction that occur. To reduce exergy destruction, this can be done by modifying the operating conditions of the package boiler. The results show that 94.3% of the total exergy destruction from the boiler package is obtained from the evaporator component with a value of 2.7 x 108 kJ/hr Modification of the operating conditions of the evaporator is carried out by reducing Boiler Feed Water (BFW) inlet temperature with T 100C (196 – 116 oC). The decrease BFW temperature will increase the amount of required latent heat and reduce the convection heat that will be carried by the flue gas to generate superheated steam. Optimization of the BFW temperature is performed be calculating the flue gas temperature and exergoeconomic analysis. Exergoeconomic analysis is performed by calculating the cost rate of exergy destruction (ĊD,k) and exergoeconomic factor (fk). The results obtained were that the temperature was optimum of BFW is at 161°C which resulted the reduction of exergy destruction of 6,2x106 kJ/hr and resulting difference cost losses based on actual data (196 oC) of Rp 1,370,354,743/hr. Exergetic Sustainability Index (ESI) used to demonstrate how reducing a system's environmental impact can be achieved by reducing its exergy consumption (destruction and losses) or increasing its exergetic efficiency. In this research, ESI Value was achieved at 0.918.

Thermodynamics modelling and optimisation of a biogas fueled decentralised poly-generation system using machine learning techniques

In the forthcoming era of smart energy systems, decentralised solutions are gaining increasing prominence due to their superior adaptability for interconnecting sectors, reduced inefficiencies, and environmentally friendly operation. This study introduces a new medium-scale biogas-based power plant that utilises a gas turbine to meet the energy needs of a specific locality, encompassing electricity, heating, cooling, and water supply, all whilst considering the system's environmental impact. To optimise the plant's performance, three different multi-objective optimisation scenarios employing machine learning methodologies and Greywolf algorithms with distinct objective functions are analysed. Under the base conditions, the proposed plant showcases impressive capabilities, delivering 1372 kW of electricity, 246.2 kW of heating, 293.3 kW of cooling, and 4.1 kg/s of distilled water. It operates with first and second law thermodynamics efficiencies of 72.3 % and 41.4 %, respectively, while maintaining a CO2 emission index of 0.778 kgCO2/kWh. Furthermore, the net present value and investment return period for the investment are estimated to be approximately 4.4 million USD and 4 years, respectively. Through optimisation (scenario 1) that prioritises maximising efficiency while minimising product costs and environmental impact, the following parameters are achieved: an exergy efficiency of 42.7 %, a cost of products at 28.8 $/GJ, and a reduced CO2 emission index of 0.762 kgCO2/kWh. The results reveal that the proposed system not only excels in efficiency but also proves to be economically viable and environmentally beneficial.

Life-cycle assessment of a radiant high-temperature cooling system in the Mediterranean climate

As sustainable development increases its significance in policy-making, methods for quantifying the sustainability of a project become more important. One such method is life-cycle assessment (LCA). In this study, an LCA assessment of a radiant cooling system was conducted for a retrofit project of a small office building. The studied building is located in Sant Cugat in north-eastern Spain. The radiant cooling system was also compared with a conventional alternative, an all-air variable air volume system. The goal of the study is to provide a generalisable methodology for conducting an LCA-assessment in a retrofit project involving cooling. The methodology of the assessment consists of two parts. Building energy models in IDA-ICE 4.8 were used to determine the energy use of the systems and the resulting thermal comfort conditions in the building, while SimaPro 9.4 was used to carry out the LCA assessment. A major novelty in the study is the use of thermal comfort as the functional unit for the LCA assessment. The results show that the radiant system has a lower environmental impact in all ReCiPe2016 midpoint impact categories during the systems' estimated lifetime of 50 years. However, a sensitivity analysis revealed that while the radiant system's environmental impact is mainly dependent on the manufacturing process, the conventional system's impact is largely determined by its operational energy use. Therefore, the conventional system is significantly more sensitive to decarbonisation of electricity production.

Multi-objective optimization of milk powder spray drying system considering environmental impact, economy and product quality

Performance optimization of the milk powder spray drying system is of great significance to the sustainable development of the dairy industry with the growing market demand for milk powder. The present study aims to propose a multi-objective optimization framework for the drying system to improve the environmental performance, economic performance, and product quality of the system. For this purpose, inlet air temperature, feed pump speed, and atomization pressure are taken as the decision variables. A multi-objective optimization model of the system is established to minimize the system's environmental impact and life cycle cost and maximize the quality of milk powder. In order to solve the problem more efficiently, the non-dominated sorting ant colony genetic algorithm is proposed. The artificial neural network is adopted to construct the surrogate model for the life cycle assessment of the system and the Pareto front is obtained. The TOPSIS method is used to make decisions from the Pareto front to obtain the optimal scheme. The deviation index is adopted to evaluate the schemes obtained by different optimization methods. To demonstrate the advantages of the proposed framework, a case study is carried out and the optimal scenario obtained by the framework is compared with two different goal-oriented solutions, including bi-objective optimization that minimizes the environmental impact and life cycle cost of the system, and single-objective optimization that maximizes the quality of milk powder. The results show that the multi-objective optimization scheme can improve the performance of the system more comprehensively compared with dual-objective optimization and single-objective optimization. The optimized system achieves a good trade-off between environmental friendliness, economy, and quality of milk powder at the following conditions: the inlet air temperature of 182.98 °C, the feed pump speed of 80.74 rpm, and the atomization pressure of 180.34 bar. The environmental impact and the life cycle cost of the optimized system are reduced by 9.0% and 10.56%, respectively, compared with the original system, and the quality of milk powder is improved by 4.35%. The performance of the proposed method in the generational distance, spread and inverted generational distance is improved by more than 36.58%, 30.76% and 87.10%, respectively, compared with common algorithms such as NSGA-II, MOEA/D, NSGA-III, SPEA2. The solutions obtained using the proposed approach have the best performance in the three objectives compared with the schemes obtained by the other algorithms. The LCA surrogate model can reduce the solving time of the optimization from 3.5 h to 8.68 s on the premise of meeting the accuracy.

Integrated spatially explicit landscape and cellulosic biofuel supply chain optimization under biomass yield uncertainty

This paper proposes an integrated stochastic mixed-integer linear programming model for biofuel supply chain and landscape design optimization that considers the interactions between uncertainty in biomass yield, spatially explicit feedstock availability, supply chain configuration, operational decisions, and the system's environmental impact. By modeling crop establishment and fertilization as strategic decisions made before the realization of uncertainty, model solutions identify integrated supply chain configurations better suited to mitigate uncertain biomass yields. Importantly, the paper presents an approach for gathering and processing the large amount of necessary real-world data, including an accurate accounting of soil carbon sequestration. A case study located in Michigan, USA, demonstrating the capabilities of the integrated model with realistic data, is presented. Results at a variety of harvesting site resolutions and number of uncertainty scenarios, show that large-scale instances, at fine spatial resolutions, identify attractive environmental solutions and that solving the stochastic problem leads to an economic benefit.

Machining feasibility and sustainability study on end milling process of Monel alloy

Minimizing the resource consumption and reducing the manufacturing system's environmental impact has been increased in today's manufacturing trend. The proposed study deals with the sustainability of the machining process of Monel (K-400) in the End milling process. Spindle speed feed and depth of cut are process parameters of the milling process and are set as four levels. Surface roughness, MRR, Tool wear, tool life, and energy consumption were considered as sustainability factors. The result revealed that factors such as Lower surface roughness (1.26 µm), Minimum tool wear (0.2 mm), Maximum tool life (8,79,200 min), Maximum material removal rate (32 mm3/s) increased the sustainability of the end milling process of Monel material.

Exergy efficiency of solar energy conversion to biomass of green macroalgae Ulva (Chlorophyta) in the photobioreactor

Offshore production of macroalgae biomass, which was recently given the name seagriculture, is one of the important but least explored alternative energy resources. Unlike microalgae, macroalgae cultivation can be done offshore and therefore brings real news to the biofuel – food land agriculture conflict. A wide variety of small-scale laboratory experiments are done lately in order to deepen the knowledge and develop expertise in macroalgae cultivation and its downstream processing. For energy applications, it is common to evaluate the performance of an energy source or system in exergy efficiency terms. Another important parameter that is evaluated to determine the system's environmental impact is it’s volumetric and areal footprint. The current work examines two exergy efficiency indexes, the Exergy Efficiency (EE), which takes into account all exergy inputs, and the Exergy Return On Investment (ExROI), that includes only fossil fuel exergy inputs, both on a green macroalgae Ulva grown in the macroalgae photobioreactor system (MPBR) incorporated into a building. Cultivation of macroalgae in the building embedded MPBR achieved maximal values of 0.012 and 0.22 for EE and ExROI, compared to a range of 0.05–8.34 and 0.013–0.327 found in published papers of microalgae systems. In addition, a modelled optimization of the initial biomass density leads to maximal values of about 0.035 for EE and 0.433 for ExROI, while further improvement may be achieved by optimization of nutrient addition and mixing methodology. This work demonstrates a tool to measure the performance of laboratory scale macroalgae biomass cultivation systems, followed by preliminary efficiency and environmental impact values, important for future upscaling.

Investigation on the performance and environmental impact of a latent heat thermal energy storage system

The present work provides an investigation into the performance of a thermal energy storage system. The energy storage device considered in the work is paraffin wax, which is a phase change material. Air serves as the heat transfer fluid in the present work. The performance of the system was evaluated in terms of overall energy and exergy losses, overall energy and exergy efficiencies, as well as heat exchanger effectiveness. The environmental impact of the system was also considered in term of sustainability index. The computational work was performed using the Engineering Equation Solver (EES) software. Parametric studies were also carried out to study the effects of various influential parameters like inlet temperature of heat transfer fluid during charging and discharging periods, air flow rate, and surrounding temperature. It was found that increasing the inlet temperature during charging and discharging, and air flow rate leads to increase in losses, thus reduces the efficiencies. However, effectiveness of the heat exchanger was observed to increase with a rise in the inlet fluid temperature during the charging period. Exergy loss and efficiency of the system reduce with an increase in the surrounding temperature. The surrounding temperature does not, however, affect the energy loss and overall energy efficiency of the system. Results further showed that the sustainability index of the system increases with any parameter that leads to an increase in the exergy efficiency.

Life cycle assessment optimization of hybrid power gas heat pump integrated with photovoltaic

Building energy consumption accounts for a large proportion in the total social energy consumption and solar energy plays an important role in the building renewable energy system. A novel hybrid power gas heat pump system integrated with photovoltaic is put forward in this paper. An optimization design based on life cycle assessment for the solar assisted hybrid power gas heat pump system (SHPGHP) is proposed in consideration of three main environmental impact factors: human health, ecosystem quality and resources. The normalized environmental impact for the system during the whole life cycle is chosen as the objective to minimize the life cycle environmental impact. The influence of main independent decision variables is employed including the photovoltaic ratio, transmission ratio and mixing degree. Results show that the optimal photovoltaic ratio is 0.4. The system's environmental impact potential increases with the increase of transmission ratio and decreases with the increase of mixing degree.

Carbon footprints of heating oil and LPG heating systems

For European homes without access to the natural gas grid, the main fuels-of-choice for heating are heating oil and LPG. How do the carbon footprints of these compare? Existing literature does not clearly answer this, so the current study was undertaken to fill this gap.Footprints were estimated in seven countries that are representative of the EU and constitute two-thirds of the EU-27 population: Belgium, France, Germany, Ireland, Italy, Poland and the UK. Novelties of the assessment were: systems were defined using the EcoBoiler model; well-to-tank data were updated according to most-recent research; and combustion emission factors were used that were derived from a survey conducted for this study.The key finding is that new residential heating systems fuelled by LPG are 20% lower carbon and 15% lower overall-environmental-impact than those fuelled by heating oil. An unexpected finding was that an LPG system's environmental impact is about the same as that of a bio heating oil system fuelled by 100% rapeseed methyl ester, Europe's predominant biofuel. Moreover, a 20/80 blend (by energy content) with conventional heating oil, a bio-heating-oil system generates a footprint about 15% higher than an LPG system's.The final finding is that fuel switching can pay off in carbon terms. If a new LPG heating system replaces an ageing oil-fired one for the final five years of its service life, the carbon footprint of the system's final five years is reduced by more than 50%.

Consequences of Different Meteorological Scenarios in the Environmental Impact Assessment of Tritium Release

The environmental impact of systems managing large (kg) tritium amount represents a public scrutiny issue for the next coming fusion facilities as ITER and DEMO. Furthermore, potentially new dose limits imposed by international regulations (ICRP) shall impact next coming devices designs and the overall costs of fusion technology deployment. Refined environmental tritium dose impact assessment schemes are then overwhelming. Detailed assessments can be procured from the knowledge of the real boundary conditions of the primary tritium discharge phase into atmosphere (low levels) and into soils. Lagrangian dispersion models using real-time meteorological and topographic data provide a strong refinement. Advance simulation tools are being developed in this sense. The tool integrates a numerical model output records from European Centre for Medium range Weather Forecast (ECMWF) with a lagrangian atmospheric dispersion model (FLEXPART). The composite model ECMWF/FLEXTRA results can be coupled with tritium dose secondary phase pathway assessment tools. Nominal tritium discharge operational reference and selected incidental ITER-like plant systems tritium form source terms have been assumed. The real-time daily data and mesh-refined records together with lagrangian dispersion model approach provide accurate results for doses to population by inhalation or ingestion in the secondary phase.

Economic paper blending optimization model with competing materials

PurposeDemanding customers, legislation and raw materials shortages in the modern world have forced companies to minimize the system's environmental impact. The paper seeks to analyze the economic impact of blending in sustainable paper industries in countries such as India.Design/methodology/approachA linear programming model for a paper supply chain is proposed to minimize paper manufacturing cost by optimally blending wood pulp and after‐use paper under various conventional supply chain constraints. The issues of quality, environmental concern and reusability in the paper industry have also been taken into account.FindingsImproving quality of after‐use paper by proper recovery network reduces the manufacturing cost. Increasing proportion of wood fiber in the finished paper decreases the cost, even at the cost of degradation in the environment. Thus, it is up to the manufacturer to reflect its degree of environmental concern to the government and society by assigning appropriate environmental and quality opportunity costs in the model.Research limitations/implicationsDifficulty in obtaining the estimates of the environmental and quality cost is a major limitation of the study.Practical implicationsThis research provides manufacturers with a simple mathematical model to compare the economic feasibility of blending wood pulp and after‐use paper depending on the market situation.Originality/valueThe major contribution of the model is its capability to study the economic impact of blending by considering some of the important sustainable development issues like environment, quality, shortage, and reusability under one objective function.

Environmental evaluation of an air-conditioning system supplied by cooling energy from a bore-hole based heat pump system

An evaluation of the environmental impacts of an air-conditioning system which uses a bore-hole system for heating and cooling is the aim of this case study. To facilitate the evaluation, the bore-hole based air-conditioning system is compared with a reference system that uses a more traditional source of heat (district heating) and cooling energy (refrigeration). Environmental impacts of the system are examined by the life cycle assessment (LCA) method, including the weighting step. Results show that the bore-hole based system performs better in three of the four impact categories investigated: acidification, eutrofication, and global warming potential (GWP) with a 100-year horizon. This is mainly due to the fact that it uses less material in the production phase and less operating energy during the user stage. However, in the category of photochemical ozone creation potential (POCP), it performs four times worse than the more traditional system. Nevertheless, the overall environmental impact of the bore-hole based system, evaluated by common weighting methods, is better than the more traditional system. The most dominant environmental impact of both systems arises from the operating energy, although the energy use in the building studied is low.

Assessment and Improvement of the Efficiency of Nitrogen Use in Clover Based and Fertilizer Based Dairy Systems. 2. Beyond Benchmarking to Internal System Components

ABSTRACT In order to understand better how the losses of N from farm systems may be controlled and reduced, it is necessary not only to consider farm gate budgets, which provide a useful benchmark for the overall potential environmental impact of a system. Internal flows of nitrogen were quantified for two dairy systems; GC relying on N fixation by white clover and GN using purchased mineral N fertilizer, both before and after modifications to improve the nitrogen efficiency (N in milk/N in inputs) of the whole systems. The greatest difference in N balance between GC and GN systems was found in the soil/crop component. This component showed a greater imbalance between inputs and outputs for GN (58%) than for GC (originally 82%, improved to 88%), indicating more potential for losses from the GN system to the environment. The animal was shown to be the least efficient component of all systems, with an initial efficiency of 20%, improving to 23% (GC) or 24% (GN) following modifications. The efficiency of nitrogen use for milk production is greater when animals are housed than during grazing, since diets can be more carefully controlled. The limitations of assessing the environmental impact of systems using parameters based partly on estimates must be recognized. Tolerance limits must be established if such values are used in advice or legislation.