Life Cycle Cost Of System Research Articles

A novel method for sizing of standalone photovoltaic system using multi-objective differential evolution algorithm and hybrid multi-criteria decision making methods

Abstract Standalone photovoltaic system is promising sustainable energy source. Accurate modeling and sizing of these systems strongly affect the system's feasibility. Thus, in this paper, optimal sizing of standalone photovoltaic system is conducted based on multi-objective differential evolution algorithm integrated with hybrid multi-criteria decision making methods. Multi-objective differential evolution algorithm is used to optimize set of configurations of a system by minimizing technical and cost objective functions simultaneously. After that, an analytical hierarchy process integrated with a technique for order preference by similarity to ideal solution are used to order preference of configurations based on the loss of load probability and life cycle cost of system. The results of the proposed sizing method are validated by a numerical method to explain the superiority of the proposed method. According to results, the proposed sizing method is faster than numerical method by around 27 times. This is because the multi-objective differential evolution algorithm requires roughly 0.23 of simulations that is required by numerical method. Furthermore, the performance of multi-objective differential evolution algorithm is evaluated by various metrics. As a result, for the adapted load demand, the optimal configuration is 63 PV modules and 66 battery unit with maximum capacity of 500 Ah.

Solar Assisted Pyrolysis of Plastic Waste: Pyrolysis oil Characterization and Grid-Tied Solar PV Power System Design

The principal objective of this study is to test the performance of plastic waste pyrolysis reactor and to design a grid-tied solar PV power system to serve the energy demand of the reactor. The goal is to convert solid waste to alternative fuels and to use renewable energy to assist in the thermal chemical conversion process. For the experimental study, plastic particles (3-4 mm in diameter) are pyrolyzed in a small laboratory reactor at atmospheric pressure and temperature of 500oC to produce liquid fuel (pyrolysis oil), hydrocarbon gas fuel (syngas), and solid residues (char). The amount of pyrolysis oil and syngas produced are determined. The physical and chemical properties of the pyrolysis oil (density, dynamic viscosity, the calorific value and chemical composition) are measured and compared with standard Diesel fuel. The daily energy demand of the pyrolysis reactor (5.1 kWh/day) is determined based on the voltage and current measurements of the heater system of the reactor. Modeling and simulation analysis using grid-tied solar PV energy system to power the pyrolysis reactor was investigated. The performance and life cycle cost of the hybrid power system was determined. The results show that solar PV can be used to assist the thermochemical conversion process. Solar PV system can generate up to 52% of the total power demand of the reactor AC load. The proposed grid-tied power system with the excess power from solar PV system sold back to the grid is sustainable (the renewable fraction is 50.4%), economically viable (86$/MWh), and produce low greenhouse gas emissions (162 kg CO2/MWh).

Optimal plant layout considering the safety instrumented system design for hazardous equipment

The safety of the process plant depends on the adequate separation between the assets and the hazardous units, along with the installation of protection devices. Several mathematical approaches have been proposed to reduce the risk of the explosions through the solution of the facility layout problem, but no model has included the design of the safety instrument systems. In this work, a MINLP approach was developed to solve three issues at the same time: the process equipment layout, the facility layout, and the safety instrumented system design. This approach aims to find the optimal facility layout that minimizes the land cost, the pipeline cost, and the lifecycle cost of each safety instrumented system, reducing the risk of explosions and keeping safety as much as possible the plant assets. The model was applied to find the optimal facility layout of ethylene oxide plant for different tolerable risk frequencies. In this way, this approach provides valuable information during the design stage and substantial support for decision-makers.

An equivalent photovoltaic solar system to solve the problems of electricity in Iraqi houses

Since 1991, Iraqi society suffers from the lack of electricity power because of an economic embargo imposed from 1991 to 2003 and the mismanagement that hit Iraq after its occupation in 2003. These reasons were leaded to major problems in the power plants and their transmission lines which led to insufficient power generation. To meet this problem, the Iraqi families were tended to use two types of generators (neighborhood and household generators) as alternative sources for compensating the lack of electricity. In this study, a 3 kW photovoltaic (PV) solar system was proposed to use the solar energy in Iraqi houses. An economic feasibility analysis by calculating the life cycle cost was investigated to compare the cost of PV system with the two alternatives sources of generators. At current market price of PV panels (700 IQD/W), a 3 kW PV system has the ability to supply the Iraqi house with electrical energy in total cost about (4,386,366 IQD ≈ 3655 USA$) for five years. The life cycle cost of PV system was investigated about 12.27% less than the two generators cost. Therefore, PV system is more economic in Iraqi houses under the deterioration in the electricity sector. Furthermore, the PV solar not pollutes the environment as the case of using generators.

Ballast Water Treatment System Integration and Life Cycle Cost Analysis for Dry Bulk Carrier

Ballast Water Treatment System Integration and Life Cycle Cost Analysis for Dry Bulk Carrier

Optimal planning of renewable energy source and energy storage in a medium‐ and low‐voltage distributed AC/DC system in China

As the quantity of DC load and distributed generation system increases in China, AC/DC distribution system is arousing more and more research interest for its high-efficiency distribution ability. In this study, the optimal size and location of renewable energy source (RES) and energy storage in a medium- and low-voltage distributed AC/DC system is studied. A modelling method for the optimisation of such hybrid AC/DC system is developed. The objective of the proposed optimisation method is to minimise the life cycle cost of the system with consideration of the life span of RES. The planning method is based on energy balances and constraints of system operation. The utility requirements and subsidy in China for such system are also considered in the planning process. The method is demonstrated in a 10 kV and low-voltage distributed AC/DC system considering installing photovoltaic system, wind turbines, and electric storage system. The provided results indicate that the method is effective and applicable for the optimisation of the size and location of RES in distributed AC/DC system. The life cycle cost of such system is significantly reduced with the subsidy of the Chinese government compared with the system without RES.

Life Cycle Cost of Heat Supply to Areas with Detached Houses—A Comparison of District Heating and Heat Pumps from an Energy System Perspective

There are different views on whether district heating (DH) or heat pumps (HPs) is or are the best heating solution in order to reach a 100% renewable energy system. This article investigates the economic perspective, by calculating and comparing the energy system life cycle cost (LCC) for the two solutions in areas with detached houses. The LCC is calculated using Monte Carlo simulation, where all input data is varied according to predefined probability distributions. In addition to the parameter variations, 16 different scenarios are evaluated regarding the main fuel for the DH, the percentage of combined heat and power (CHP), the DH temperature level, and the type of electrical backup power. Although HP is the case with the lowest LCC for most of the scenarios, there are alternatives for each scenario in which either HP or DH has the lowest LCC. In alternative scenarios with additional electricity transmission costs, and a marginal cost perspective regarding the CHP investment, DH has the lowest LCC overall, taking into account all scenarios. The study concludes that the decision based on energy system economy on whether DH should expand into areas with detached houses must take local conditions into consideration.

Rural water asset management practices in Ghana: the gaps and needs

AbstractThis study evaluates primary and secondary data from two districts to assess the status of asset management practices, and to examine requirements for improved asset management. Asset inventory data shows that asset management practices in the districts are currently poor, leading to high rates of nonfunctionality and low service levels. The existing ‘fix on failure’ approach to water systems’ repair has become a common practice. However, many repairs which relied on ‘fix on failure’ were found to have delayed, often due to the length of time it takes to mobilise financial resources from ‘post‐paid’ water users. This paper contends that without an improved asset maintenance, system it is likely that rural water systems in Ghana will continue to provide unsustainable services. The Findings demonstrate that improving the current asset management practices is dependent on human and financial resources, access to timely water service monitoring data at district levels, and planning and budgeting regime to reflect life cycle costs of water systems.

RAMS Analysis of Train Air Braking System Based on GO-Bayes Method and Big Data Platform

The RAMS (reliability, availability, maintainability, and security) of the air braking system is an important indicator to measure the safety performance of the system; it can reduce the life cycle cost (LCC) of the rail transit system. Existing safety analysis methods are limited to the level of relatively simple factual descriptions and statistical induction, failing to provide a comprehensive safety evaluation on the basis of system structure and accumulated data. In this paper, a new method of safety analysis is described for the failure mode of the air braking system, GO-Bayes. This method combines the structural modeling of the GO method with the probabilistic reasoning of Bayes methods, introduces the probability into the analysis process of GO, performs reliability analysis of the air braking system, and builds a big data platform for the air braking system to guide the system maintenance strategy. An automatic train air braking system is taken as an example to verify the usefulness and accuracy of the proposed method. Using ExtendSim software shows the feasibility of the method and its advantages in comparison with fault tree analysis.

Bidirectional handshaking LSTM for remaining useful life prediction

Abstract Unpredictable failures and unscheduled maintenance of physical systems increases production resources, produces more harmful waste for the environment, and increases system life cycle costs. Efficient remaining useful life (RUL) estimation can alleviate such an issue. The RUL is predicted by making use of the data collected from several types of sensors that continuously record different indicators about a working asset, such as vibration intensity or exerted pressure. This type of continuous monitoring data is sequential in time, as it is collected at a certain rate from the sensors during the asset's work. Long Short-Term Memory (LSTM) neural network models have been demonstrated to be efficient throughout the literature when dealing with sequential data because of their ability to retain a lot of information over time about previous states of the system. This paper proposes using a new LSTM architecture for predicting the RUL when given short sequences of monitored observations with random initial wear. By using LSTM, this paper proposes a new objective function that is suitable for the RUL estimation problem, as well as a new target generation approach for training LSTM networks, which requires making lesser assumptions about the actual degradation of the system.

Development of Software for Life Cycle Cost Analysis of Solar Photovoltaic (PV) and Diesel Generator Systems in Nigeria

The human and economic development of any nation is largely tied to the availability of energy, hence the need for an adequate supply of electricity by reliable energy systems. Nigeria’s economic growth is undermined by the epileptic nature of its electricity supply system. Consequently, the populace is forced to turn to alternative sources of power. However, this presents another problem - conflict of choice between available options for power generation. There is, therefore, the need to assist electricity consumers in Nigeria make better and cost-effective choices in this regard. In this paper, a software computer program is developed to determine/compare life cycle cost (LCC) of solar photovoltaic (PV) and diesel generator systems as preferences for electricity generation in Nigeria. The software is developed through an approach involving load determination, energy resources determination, system sizing and a typical residential building. The key methodology adopted is evolutionary prototyping which focuses on vertical dimension approach. Typical load description of a household located in Amawbia Awka of Anambra state in Nigeria was used to test the efficiency of the source code. The initial cost and life cycle cost for the two systems over a period of 30 years was ascertained. The test results showed the solar PV system to be a more cost-effective solution than the diesel generator based on total life cycle costs. The study recommends among others, the need to increase awareness of the long-term benefits of solar energy systems as an alternative source of electricity in Nigeria.

Smart working fluid selection in refrigeration systems

The choice of trade-off working fluid in the reverse Rankine cycle was studied as a problem of fuzzy optimization. Three main criteria were chosen as objective functions: thermodynamic (COP – coefficient of performance), economic (LCC – cost of life cycle) and ecological (GWP - global warming potential). The control variables (X) were considered as information characteristics of the working fluid. Critical parameters and a normal boiling point represented the latter. A sustainable solution that implements a compromise between the criteria based on information technology, defines a "smart" working fluid. The local criteria were expressed through the thermodynamic properties restored from the information characteristics of the working fluid X. The life cycle cost of the refrigeration system was calculated according to standard economic ratios. GWP values were selected from the refrigerant database. The class of substances considered is represented by possible alternative refrigerants for replacing R410A.

Economic Analysis of WECSs Using LCOE and PVC Approaches in Northern Ethiopia

In this study, the relative economic contrast of wind energy conver-sion systems (WECSs) are examined using levelized cost of electricity(LCOE) and present value cost (PVC) as measures of merit of systemlife cycle cost. From the analysis of data and discussion, capacity factorand useful life of the wind turbine have a positive impact on the costof electricity produced by the WECS, while the other input parametersof LCOE and PVC increase the system life cycle cost, as their values in-creases. The trend of capacity factors decreased linearly, and the simul-taneous increase in LCOE and PVC was noticed.

A Petri Net-based life cycle cost analysis approach

Railway infrastructure providers, such as Network Rail, who owns and manages the British railway infrastructure, can improve the performance and reduce the life cycle cost of their assets through delivering effective asset management. Having the capability to use computer-based models to predict the future performance and life cycle cost of an asset group is a key enabling mechanism for implementing effective asset management. Decision makers can determine the optimum maintenance strategy and the best allocation of capital expenditure based on evidence from modelling results. This paper shows how probabilistic modelling can be used to evaluate asset management projects of the railway overhead line equipment system and undertake a life cycle cost analysis through the use of a stochastically timed high-level Petri Net. A complete modelling framework has been developed, where the components and their maintenance strategies are selected as inputs, and the Petri Net model is used to calculate outputs associated with the performance and life cycle cost of the overhead line equipment system for the corresponding components and strategies considered. This paper presents the practical use of the developed model and describes how the outputs can be used by asset managers to understand the expected system performance and cost over its life cycle. The range of outputs described are the most detailed for such models studying the overhead line equipment and other engineering systems in literature. Whilst the railway overhead line equipment system is used as an example study, the modelling framework is transferable to asset management projects for other engineering systems.

Economic Analysis of WECSs Using LCOE and PVC Approaches in Northern Ethiopia

ABSTRACTIn this study, the relative economic contrast of wind energy conversion systems (WECSs) are examined using levelized cost of electricity (LCOE) and present value cost (PVC) as measures of merit of system life cycle cost. From the analysis of data and discussion, capacity factor and useful life of the wind turbine have a positive impact on the cost of electricity produced by the WECS, while the other input parameters of LCOE and PVC increase the system life cycle cost, as their values increases. The trend of capacity factors decreased linearly, and the simultaneous increase in LCOE and PVC was noticed.

Predictive Maintenance Optimization for Aircraft Redundant Systems Subjected to Multiple Wear Profiles

Researchers and industry practitioners have recently demonstrated great interest in maintenance planning since it directly impacts the lifecycle cost and availability of systems. Considering the aviation industry, this impact is even more relevant due to high-availability expectations from aircraft operators and high costs incurred when an aircraft becomes out of service. For this reason, some minor maintenance activities are carried out near the gate, between two consecutive flight legs. These activities are referred to as aircraft line maintenance. The usage of prognostics and health management techniques may help the prevention of unexpected events when caused by degrading components. The application of prognostics techniques together with a line maintenance planning optimization approach is not a trivial task and requires sophisticated mathematical approaches especially when dealing with complex and integrated systems. This paper proposes a methodology for predictive line maintenance optimization of redundant aeronautical systems subjected to multiple wear conditions. Degradation trends and future wear values are estimated considering an implementation of a multiple model approach of the extended Kalman filter technique. Planning optimization is based on the minimization of operational costs comprising several aspects of the aviation industry such as dispatch requirements, delays, cancellations, and equipment costs. A case study is conducted using field prognostics data of hydraulic systems to evidence the efficiency and benefit of the proposed methodology.

Thermoeconomic modeling of a small-scale gas turbine-photovoltaic-electrolyzer combined-cooling-heating-and-power system for distributed energy applications

Abstract The purpose of this study is to investigate the potential of a small-scale, combined-cooling-heating-and-power system, consisting of a 1 MWe gas turbine subsystem coupled to a 0.5 MWe photovoltaic (PV) subsystem for application in Cyprus. The proposed system is completely autonomous, without any interconnections to a central power grid. To allow maximum utilization of the electricity generated by the PV subsystem, an electrolyzer unit is coupled to the system to convert excess renewable electricity to hydrogen. The generated hydrogen is injected to the natural gas supply for the gas turbine. For the generation of useful cooling and heating, the system recovers heat from the flue gas exiting the gas turbine; the recovered heat is supplied to a heat-activated absorption chiller/heater to generate cooling or heating. An electric chiller/heater is integrated to the system to supplement thermal energy when necessary. The thermal energy is supplied to nearby buildings through a district energy network. The annual average primary energy ratio of the proposed system is 0.806. For an assumed system lifetime of 20 years, the lifecycle cost of the proposed system is 11.12 million USD, resulting to a unit cost of electricity at 0.06 USD/kWh, which is a 62% reduction of the current cost in Cyprus. The results of the parametric study suggest that the economic performance of the proposed system is highly dependent on price fluctuations of the unit cost of natural gas, while the specific cost of the electrolyzer unit is also critical. The proposed system could become an important candidate for power and thermal energy generation in Cyprus as a measure to reduce the presently high cost of electricity.

Configuration Selection Based On Lifecycle Cost Of Subsea Production System: Case Of Indonesia Deepwater Field

Subsea tie back systems are important parts of oil and gas production project. The decision to select a subsea tie-back configuration with the objective goal of lowest lifecycle cost can be configured in multiple ways based on the field specifications and operator’s approach to operation. This paper presents an Analytic Hierarchy Process (AHP) method to determine economical levels of subsea tie-back wells configuration, based on lifecycle cost of subsea deepwater production systems with respect to wells number alternative. Field reservoir located in deepwater of eastern Indonesian with the depth of 1400 meters and field life 40 years is studied. From this study, it is identified that the most economical configuration in subsea production systems: satellite tie-back configuration to develop small field with 6 numbers of wells; for 12 numbers of wells, template subsea tie-back configuration is the best .

A model-based design optimization strategy for ground source heat pump systems with integrated photovoltaic thermal collectors

This paper presents a model-based design optimization strategy for ground source heat pump systems with integrated solar photovoltaic thermal collectors (GSHP-PVT). A dimension reduction strategy using Morris global sensitivity analysis was first used to determine the key design parameters of the GSHP-PVT system. A model-based design optimization strategy was then formulated to identify the optimal values of the key design parameters to minimize the life-cycle cost (LCC) of the GSHP-PVT system, in which an artificial neural network (ANN) model was used for performance prediction and a genetic algorithm (GA) was implemented as the optimization technique. A simulation system of a GSHP-PVT system developed using TRNSYS was used to generate necessary performance data for dimension reduction analysis, and for the ANN model training and validation. The results showed that the ANN model used was able to provide an acceptable prediction of the operational cost of the GSHP-PVT system. In comparison to two baseline cases, the 20-year life cycle cost (LCC) of the GSHP-PVT system studied can be decreased by 20.1% and 10.2% respectively, when using the optimal values determined by the proposed optimization strategy. This design optimization strategy can be potentially adapted to formulate the design optimization strategies for GSHP systems and other building energy systems.

Toronto TO360 Pilot Evaluation and the Case for Pedestrian Wayfinding ( breakout presentation )

Background Following other ‘legible city’ projects, the City of Toronto initiated the TO360 Wayfinding Strategy in support of walking as the connecting mode that enables sustainable transportation. A pilot scheme delivered in 2015 provided a baseline for evaluation in support of a business case for citywide roll-out. Description TO360 is comprehensive multimodal strategy for pedestrian, vehicular, cyclist and transit users. The pedestrian pilot consists of on-street signage and maps at transit shelters and street furniture. Signs are deployed to support the most legible routes connecting arrival points and destinations, but also reveal the offer of the area, promoting wandering and exploration. Maps incorporate features to support walking such as 5-min walking circle, heads-up orientation and landmark buildings. Outcomes The objective of the pilot is two-fold: test user understanding and physical qualities of products, and provide an evaluation baseline. Pre- and post-implementation surveys were undertaken 12 months apart to measure change. After the pilot, rating for users to help finding their way around increased from 61% to 89%; to help making informed choices about walking routes increased from 39% to 83%; and, to learn about new and interesting locations or attractions increased from 44% to 82%. Results are comparable to other cities, notably to Legible London which also run an evaluation three years after implementation that demonstrated that as the wayfinding system expands it delivers increased awareness and confidence to explore. Implications Based on the system life-cycle costs and benefits, the indicative benefit cost ratio for Toronto is estimated at 3.7:1. This means that for every dollar invested, nearly $4 is returned through transportation benefits such as pedestrian and auto journey time savings. The case for TO360 is further enhanced by other non-monetized benefits such as additional tax revenues from retail, tourism, reduction in emissions and health care costs. However, benefits in terms of footfall and visitor expenditure are harder to justify beyond downtown areas. A recommended implementation would be to combine high quality signage in dense areas with potential for walking with more cost-effective solutions such printed and digital maps across the city, creating a consistent pedestrian information fabric.