•A new floating salt rejecting solar desalination system is developed and tested.•The water yield increases by 64% compared to the reference passive solar still.•The Life-Cycle Unit Water Cost is 46% ...less than the reference.•Multi-layer basin provides adequate salt-rejecting and capillary water intake.•Advantages and limitations of the system, and future research avenues are discussed.
In this article, a novel floating salt rejecting solar still with a low vacuum condition on the evaporation chamber is developed and the performance is experimentally investigated. The new design adopts solar heat localization for interfacial evaporation and capillary water circulation to improve the evaporation rate and prevent the basin surface from residual salt accumulation. The basin is made in tubular structure composed of multi layers of porous foam and hydrophilic cellulose fabric for improved capillary water supply. The solar still consists of an external condensing coils coupled with the basin structure. It completely submerges into the water while the solar still is floating in the saline water reservoir (e.g. oceans). This enables the natural cooling of the condensing coils which increases the condensation rate. A low-cost hemispherical clear acrylic cover is used to capture the solar radiation from all directions on the basin. The system performance was examined under different scenarios. The system was found to generate distilled water at a daily rate of 4.3 L m−2 d−1 with the distillation efficiency of 35.6% during summer in Melbourne, Australia. The life cycle cost per litre of drinking water generated by the solar still is calculated at 4.7US ¢ L−1 which is substantially lower than conventional solar stills. This system is expected to have a lower maintenance cost as it does not require as much periodic cleaning. The new system developed is a feasible alternative to address the water security challenge for water-stressed communities at remote areas or disaster-stricken areas with no access to an energy infrastructure.
•The structural effects of multiple formulations of tornadic wind loads are examined.•A framework to assess performance capacity of a vertical structure is proposed.•Artificial neural networks are ...used to approximate structural fragilities.•Probability of limit state failure under tornadic loading is evaluated.•Modeling uncertainty affecting life-cycle cost assessment is quantified.
Despite significant advancements in computational technologies and methods, the comprehensive assessment of the performance capacities and risk of structures built in environments prone to severe natural hazards is still a daunting task under standard Monte Carlo-based simulation schemes. This issue is particularly relevant for the consideration of wind actions from loads generated by non-stationary phenomena (e.g. tornadoes) because of extreme complexities in the simulated flow field and the fluid-structure interaction. To mitigate such computational burdens, this study proposes a surrogate modeling approach that utilizes predicted fragilities from artificial neural networks (ANNs) to facilitate the performance-based assessment of a vertical structure subjected to tornadic wind loads. Calibration data for the feedforward ANNs are extracted from numerically generated responses based on a derived wind loading model that capitalizes on the developments of various analytical formulations of a tornado’s wind field. Uncertainties in the structural behavior and in the overall modeling procedure are incorporated in the process, culminating in a life-cycle cost assessment that incorporates a practical, economic value to the simulation framework. The novel application of ANNs in this study, therefore, empowers a more robust performance-based framework for the risk evaluation of structures subjected to tornado wind loads.
New thermal insulation materials made from textile waste based on acrylic and wool were developed using needle punching method. The aim of this work is to investigate the thermal performance of an ...external building wall outfitted with the developed insulation materials and submitted to the real climatic conditions of Casablanca, Morocco. A numerical finite volume model is developed and validated against the experimental results of a thermally controlled cavity at reduced scale. The numerical model is used to study the thermal performance of the considered wall in winter and summer season and to compute the annual heating and cooling loads. The thermal and energetic performances of the developed insulation materials are compared to the ones of some classical thermal insulation materials (i.e. Rock wool and Expanded polystyrene). Furthermore, a Life Cycle Cost (LCC) analysis is conducted with the local market cost in order to investigate the competitiveness of the new insulation materials and to seek the optimal insulation thicknesses. The results show that the developed thermal insulation materials are a competitive solution in terms of annual loads compared to the conventional thermal insulations. The optimum insulation thicknesses of the new materials and of the considered classical thermal insulations materials are determined using the LCC analysis. The effect of the specific cost of the developed insulation materials is studied and findings show that, the developed insulation can be a competitive solution if their initial cost don’t exceed 590 MAD/m3.
•Multiobjective optimization algorithm is used to optimize the size of PVPS.•The aggregated objective function composes of technical and economic objectives.•A wide range sets of weights of objective ...functions are tested.
In this paper, a differential evolution based multiobjective optimization algorithm is proposed to optimally size a photovoltaic water pumping system (PVPS). Three weighted individual objectives are aggregated by a single function to optimize the configuration of PVPS. Loss of load probability, life cycle cost and the volume of excess water are considered as three individual objective functions. The proposed pumping system is supposed to provide a daily water volume of 30m3 with a static head of 20m. The complexity of the initializing of the weights for each individual objective function is overcome by testing a wide range sets of weights. The performance of the system is tested based on hourly meteorological data. The performance results of the proposed system show that the loss of load probability and the average hourly water flow rate over a year time are around 0.5% and 3.297m3/h, respectively. The life cycle cost, water deficit, and cost of water unit of the system are 9911USD, 55.015m3, and 0.045USD/m3, respectively.
Building renovation is urgently required to decrease the energy consumption of the existing building stock and reduce greenhouse gas emissions coming from the building sector. Selecting an ...appropriate renovation strategy is challenging due to the long building service life and consequent uncertainties. In this paper, we propose a new framework for the robust assessment of renovation strategies in terms of environmental and economic performance of the building's life cycle. First, we identify the possible renovation strategies and define the probability distributions for 74 uncertain parameters. Second, we create an integrated workflow for Life Cycle Assessment (LCA) and Life Cycle Cost analysis (LCC) and make use of Sobol’ indices to identify a prioritization strategy for the renovation. Finally, the selected renovation scenario is assessed by metamodeling techniques to calculate its robustness. The results of three case studies of residential buildings from different construction periods show that the priority in renovation should be given to the heating system replacement, which is followed by the exterior wall insulation and windows. This result is not in agreement with common renovation practices and this discrepancy is discussed at the end of the paper.
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•Changing only the heating system is more efficient than doing a full renovation.•Social and economic parameters are crucial during the probabilistic assessment.•Heating system is the most influential parameter in building renovation.•Global sensitivity analysis is performed using Sobol’ indices.•Uncertainty quantification is performed using polynomial chaos expansion.
In recent years, much progress has been made on the development of aerospace materials for structural and engine applications. Alloys, such as Al-based alloys, Mg-based alloys, Ti-based alloys, and ...Ni-based alloys, are developed for aerospace industry with outstanding advantages. Composite materials, the innovative materials, are taking more and more important roles in aircrafts. However, recent aerospace materials still face some major challenges, such as insufficient mechanical properties, fretting wear, stress corrosion cracking, and corrosion. Consequently, extensive studies have been conducted to develop the next generation aerospace materials with superior mechanical performance and corrosion resistance to achieve improvements in both performance and life cycle cost. This review focuses on the following topics: (1) materials requirements in design of aircraft structures and engines, (2) recent advances in the development of aerospace materials, (3) challenges faced by recent aerospace materials, and (4) future trends in aerospace materials.
This paper presents a model to quantify the economic value gained by implementation of an inspection and preventive maintenance program for managing an ageing component population. The proposed ...approach is a refinement of the Bayesian value of information analysis through the consideration of an intricate interaction between parameter and temporal uncertainties associated with the gamma process of degradation. This paper presents an analytical formulation and computational approach to solve this complex problem in a multivariate setting. The paper shows that the economic value is significantly sensitive to the prior information and relative costs of preventive and corrective maintenance. Since the value of inspection is dominated by a reduction in the parameter uncertainty of the gamma process model, lifecycle cost optimization which ignores this aspect would lead to a sub-optimal solution of the problem.
•Economic value of an inspection and replacement program for ageing components.•Solution of the value of information (VOI) problem for gamma degradation process.•Study of role of epistemic & temporal uncertainties in a stochastic VOI problem.•Value of synergistic effect of information in a multiple component population.
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The demand for green buildings is growing, but the trend is below the expected level due to the perceived higher construction cost required by building investors. In addition, the ...industry or the practitioners knowledge and awareness of major operational cost savings of facilities is questionable. on that note, this study aims to establish the cost implications of green buildings via a comparative life-cycle cost analysis of two green certified industrial and one traditional building. The industrial sector is one of the largest energy consuming sectors in the world with over 50% of the world’s total delivered energy is absorbed by the sector. Energy consumption of industrial sector is likely to increase more due to the economic and population growth.
The data for the analysis were extracted from construction, operation, and maintenance expenditure budget records of the selected organisations. The analysis shows that in terms of life-cycle costs, green industrial buildings are 17% cheaper than that of traditional buildings. Though the initial construction cost of a green industrial building is 29% higher, the operation and maintenance costs of green buildings result in 23% and 15% overall savings throughout the life cycle. The findings provide further empirical proof of the benefits of green buildings, especially in industrial manufacturing where it is expected to improve future uptakes and consequently the achievement of sustainable development initiatives.
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•We investigated the costs and GHG emissions of three blue hydrogen production technologies.•Blue hydrogen cost ranges from $1.69-$2.55 per kg H2 depending on the production ...technology.•Autothermal reforming (ATR) with carbon capture and storage (CCS) and natural gas decomposition with CCS produce H2 has the lowest and highest cost, respectively.•Blue hydrogen from ATR process has the lowest GHG emissions, 3.91 kgCO2eq/kg H2.•The economics of a steam reforming plant depends on the CO2 capture rate.
Interest in blue hydrogen production technologies is growing. Some researchers have evaluated the environmental and/or economic feasibility of producing blue hydrogen, but a holistic assessment is still needed. Many aspects of hydrogen production have not been investigated. There is very limited information in the literature on the impact of plant size on production and the extent of carbon capture on the cost and life cycle greenhouse gas (GHG) emissions of blue hydrogen production through various production pathways. Detailed uncertainty and sensitivity analyses have not been included in most of the earlier studies. This study conducts a holistic comparative cost and life cycle GHG emissions’ footprint assessment of three natural gas-based blue hydrogen production technologies – steam methane reforming (SMR), autothermal reforming (ATR), and natural gas decomposition (NGD) to address these research gaps. A hydrogen production plant capacity of 607 tonnes per day was considered. For SMR, based on the percentage of carbon capture and capture points, we considered two scenarios, SMR-52% (indicates 52% carbon capture) and SMR-85% (indicates 85% carbon capture). A scale factor was developed for each technology to understand the hydrogen production cost with a change in production plant size. Hydrogen cost is 1.22, 1.23, 2.12, 1.69, 2.36, 1.66, and 2.55 $/kg H2 for SMR, ATR, NGD, SMR-52%, SMR-85%, ATR with carbon capture and sequestration (ATR-CCS), and NGD with carbon capture and sequestration (NGD-CCS), respectively. The results indicate that when uncertainty is considered, SMR-52% and ATR are economically preferable to NGD and SMR-85%. SMR-52% could outperform ATR-CCS when the natural gas price decreases and the rate of return increases. SMR-85% is the least attractive pathway; however, it could outperform NGD economically when CO2 transportation cost and natural gas price decrease. Hydrogen storage cost significantly impacts the hydrogen production cost. SMR-52%, SMR-85%, ATR-CCS, and NGD-CCS have scale factors of 0.67, 0.68, 0.54, and 0.65, respectively. The hydrogen cost variation with capacity shows that operating SMR-52% and ATR-CCS above hydrogen capacity of 200 tonnes/day is economically attractive. Blue hydrogen from autothermal reforming has the lowest life cycle GHG emissions of 3.91 kgCO2eq/kg H2, followed by blue hydrogen from NGD (4.54 kgCO2eq/kg H2), SMR-85% (6.66 kgCO2eq/kg H2), and SMR-52% (8.20 kgCO2eq/kg H2). The findings of this study are useful for decision-making at various levels.
The utilization of alternative power systems is prominent for energy transmission, supply, and security. This paper conducts an economic analysis for offshore wind farms, in which bulk power of wind ...energy is transmitted from offshore wind farms with high voltage direct current through submarine cables. The motivation is the examination of the hypothesis that any asset should be conditional on the total cost of infrastructure and installation, being at least amortized or generating profits depending on the interest rates of any countries. This hypothesis is tested with a life-cycle cost analysis using 40-year lifetime. The operation time is 27 years and conducted with a cumulative cash flow calculation. The transmission route starts from Bozcaada and Gokceada and ends in Istanbul (Turkey). Based on 600 MW voltage source converter, 222 km submarine cables are proposed to be a project for investors and decision makers. The investment seems feasible in terms of the generated profit and economic findings such as 10-year break-even point, and 121.11 M$ net present value. Sensitivity analysis reveals that government subsidies on the infrastructure and environmental costs are powerful incentives and create solutions. Thereby, economic and environmental advantages of this investment can provide a model for other selected regions in Turkey and any other country.
•The proposed transmission line starts from Bozcaada and Gokceada, ends in Istanbul.•The operation time conducted with a cumulative cash flow calculation is 27 years.•Based on 600 MW voltage source converter, 222 km submarine cables are proposed.•HVDC investment seems feasible in terms of the generated profit and economics.•Sensitivity analysis is applied concerning government subsidies and environment.
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