Higher Life Cycle Costs Research Articles

한강수계 비점오염원 저감시설의 생애주기비용 평가

환경부는 비점오염원 관리를 위해 시범사업으로 12개의 비점오염 저감시설을 경안천 유역에 설치하였으며, 2006년부터 모니터링이 시작되었다. 본 연구는 비점오염 저감시설의 오염부하량, 저감효율, 유지관리 활동 등의 장기간 수행된 모니터링 결과를 바탕으로 각 시설의 경제성을 평가하기 위해 수행되었으며, 생애주기비용(Lifecycle cost, LCC)을 분석하였다. 비점오염 저감시설의 유지관리는 시설경관을 향상시키기 위한 심미적 관리가 중점적으로 수행된 것으로 나타났으며, 저류형 시설(Retention Pond, RP)이 년간 8,483$, 침투형 시설(Infiltration System, IS)이 8,888$로 대부분 비슷한 비용이 발생한 것으로 분석되었다. LCC는 인공습지(Constructed Wetland, CW)가 가장 높은 것($418,324)으로 나타났으며, 반면에 식생형 시설(Vegetated System, VS)이 가장 낮은 것($210,418)으로 분석되었다. 본 연구에서 조사된 비점오염 저감시설의 LCC와 하수처리장 등 수질처리시설의 LCC를 비교한 결과 비점오염 저감시설이 낮은 것으로 나타났다. 한편, 처리용량 대비 생애주기비용이 높아질수록 TSS와 TN의 저감효율은 높아지는 것으로 나타났다. 이러한 연구결과는 비용효율적인 비점오염 저감시설을 설계하는데 유용하게 활용될 것으로 기대되며, 향후 LCC 모델의 기초자료에도 활용될 수 있을 것으로 판단된다. Diffuse pollution management in Korea initiated by the Ministry of Environment (MOE) resulted to the construction of pilot facilities termed Best Management Practices (BMPs). Twelve BMPs installed for the diffuse pollution management in the Kyung-An Stream were monitored since 2006. Data on the mass loading, removal efficiency, maintenance activities, etc. were gathered and utilized to conduct the evaluation of long-term performance of BMPs. The financial data such as actual construction, design and maintenance cost were also collected to evaluate the lifecycle cost (LCC) of BMPs. In this study, most of the maintenance activity was focused in the aesthetic maintenance that resulted to the annual maintenance cost of the four BMP types was closely similar ranging from 8,483 $/yr for retention pond to 8,888 $/yr infiltration system. The highest LCC were observed in constructed wetland ($418,324) while vegetated system had the lowest LCC ($210,418). LCC of BMPs was not so high as compared with the conventional treatment facility and sewage treatment plant. On the other hand, the relationship of removal efficiency on unit cost for TSS and TN was significant. This study will be used to design the cost effective BMP for diffuse pollution management and become models for LCC analysis.

Comparative analysis of separation technologies for processing carbon dioxide rich natural gas in ultra-deepwater oil fields

Offshore oil production in ultra-deepwater, with associated natural gas showing high carbon dioxide content and high gas to oil ratio, poses stringent constraints to upstream gas processing technologies. Under such circumstances, oil and gas are processed in Floating Production Storage and Offloading rigs, whose topside facilities are limited in terms of weight and footprint of equipment. Energy demands, supplied by on-site generation, also reduce the availability of space and weight to oil and gas processing. This work evaluates carbon dioxide separation alternatives applicable to this challenging scenario in terms of technical, economic and environmental aspects, considering early enhanced oil recovery as the destination of carbon dioxide. The Brazilian Pre-Salt fields are used as case study due to their unusual high capacity gas processing on the production topside, a consequence of the high gas to oil ratio and carbon dioxide content. The set of studied carbon dioxide separation technologies encompasses membrane permeation, chemical absorption by aqueous methyl diethanolamine with piperazine, physical absorption with propylene carbonate and hybrid variants physical absorption and membranes, membranes and chemical absorption, and two stages membrane, technically assessed by process simulation. Due to the continuous injection of carbon dioxide to enhanced oil recovery, the reservoir content of carbon dioxide increases along production life-cycle, which means that the performances of technologies have to be compared under short-term, mid-term and long-term carbon dioxide content in the associated gas, respectively, of 10%, 30% and 50% (mol), for gas production of 6 million sm3/d. Chemical absorption exhibits the lowest hydrocarbon losses and the lowest specific electric power consumption at the expense of the highest footprint, for all investigated scenarios. The lowest life-cycle costs are for chemical absorption and two stages membrane, respectively $0.57 and $0.46 million/GJ of exported gas, while the largest cost belongs to the hybrid membrane and chemical absorption ($1.78 million/GJ of exported gas). Chemical absorption holds the lowest carbon dioxide emission per ton of injected carbon dioxide (0.15 t/t), seconded by membrane permeation (0.19 t/t). Hybrid membrane and chemical absorption inherits the small footprint of membrane permeation and, despite its highest life-cycle cost, is recommended for flexibility reasons due to increasing carbon dioxide content in the reservoir life-time in cases of ultra-deepwater fields with high gas to oil ratio, high carbon dioxide content and early carbon dioxide enhanced oil recovery. Contrarily to the widely acceptance of membrane permeation as a leading small footprint solution, the overall performance analysis, under the adopted premises, remarkably favors chemical absorption.

Evaluation of Solar PV and Wind Alternatives for Self Renewable Energy Supply: Case Study of Shrimp Cultivation

The challenges in shrimp cultivation are the intensive electricity consumptions with associated greenhouse gases emissions, security of power supply, and environmental impact from the discharged waste water. Following Thailand energy roadmap, the renewable energy share in power production sector is targeted to be increased, for energy security and climate change mitigation. This paper evaluates six different scenarios of renewable energy implementation for shrimp farm in Thailand. The results show that the system with solar PV has higher reliability compared to the one with wind turbine at equal life cycle cost. The reliability of the system with solar PV and solar PV with battery varies significantly with the life cycle cost at low cost range then becomes stable. On the other hand, it was found to be quite stable in the cases of wind turbine with and without battery. Adding battery to the system significantly increases the reliability of solar PV and slightly increases for wind turbine. At the life cycle cost lower than $1 million, maximum reliability of the system with solar PV is around 53%. By adding battery, the reliability of the system can be up to 90%. The different magnitudes of the reliability between these two scenarios are higher at higher life cycle cost. For this case study, to reach higher than 50% reliability, the recommended renewable alternative is solar PV with battery.

A comparison between the life cycle cost of gravel and of bituminous surfacing options for feeder roads in Ghana

Feeder roads, which constitute a key component of rural transport infrastructure, play a vital role in rural development, but only 5% of the total feeder road network in Ghana has bituminous seal surfacing. The remaining 95% have either gravel or earth surfacing. However, gravel surfacing (G-S) is known to deteriorate rather rapidly necessitating expensive frequent maintenance while bituminous surfacing offers a more durable surfacing. Various life cycle cost studies have suggested that even though G-S may have lower initial construction costs, they tend to have higher life cycle costs than bituminous seal surfaced ones. However, since most of these studies are based on ideal maintenance practices, their conclusions do not reflect actual field conditions. This study seeks therefore to compare the life cycle cost of G-S with that of bituminous seal surfacing options for engineered feeder roads in Ghana using actual cost data. Data were collected from eight feeder road projects with G-S and a similar number with bituminous surfacing from six regions of Ghana completed between 2010 and 2013. The life cycle cost for each road was computed using a discount rate of 12% and an inflation rate of 15% over an analysis period of 21 years. The results for G-S are then compared with those for single bituminous seal surfacing and for double bituminous seal surfacing. The results are further compared with those from trial sections of an experimental study of Otta seal surfacing using natural gravel and using crushed rock as aggregates. The results suggest that based on the high initial construction costs of bituminous seal surfacing and actual low maintenance intervention practices, G-S remain the least cost option. The study recommends the need for alternative surfacing technology that does not involve bitumen.

A method to improve integrated product service offerings based on life cycle costing

Although a few papers have reported on life cycle cost (LCC) analysis of integrated product service offerings (IPSOs), insight on how to improve IPSOs based on LCC analysis is missing. This paper presents a method and an Excel and MATLAB-based tool that support IPSO design by employing LCC analysis, both from the provider and customer perspectives. This method takes advantage of exchangeability between products and services, being enabled within IPSO design. The method has been applied to an existing IPSO and potential improvements have been identified, e.g. one cheap component causing high LCC that could be reduced significantly by redesign.

The Effects of Multiple Green Factors on Condominium Prices

This paper analyzes the transaction prices of green buildings assessed on the basis of multiple green factors. Our theoretical model demonstrates that the initial green premium can be negative but becomes positive as the building ages if a green building has a higher life-cycle cost and a longer economic life. Our empirical analysis of green condominiums in Tokyo confirms this prediction. We additionally find that the longer-life design is associated with a price premium, but the use of renewable energy and recycled materials and water is associated with price discounts. The price discounts are interpreted as the capitalization of a greater life-cycle user cost.

Possibility to Improve Strength and Structural Stability of Bridge Deck Slabs by Using Ultra High Performance Fiber Reinforced Concrete

Parts of the bridges in Sweden and other countries have shown to have a too low resistance with respect to deterioration. This leads to costly repair interventions that disturbs the traffic and results in high Life Cycle Costs (LCC) for the bridges. This investigation primarily focuses on the mechanical behavior, durability and rheological properties and application of UHPFRC to develop more robust bridge deck slabs. UHPFRC shows better performance at post-cracking due to the strain hardening behavior with distributed micro-cracks, enhancing the service life of bridge deck slabs. The main idea is to use Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) to harden those zones of the structure that are exposed to severe environment and high mechanical loading. This conceptual idea combines efficiently protection and resistance properties of UHPFRC and significantly improves the structural performance of the rehabilitated concrete structure in terms of durability and life-cycle costs. The concept is validated by means of four applications demonstrating that the technology of UHPFRC is mature for cast in-situ and prefabrication using standard equipment for concrete manufacturing. Moreover an inventory of two bridges in Sweden has been used as case study to investigate the possibility of use of UHPFRC for rehabilitation. I. INTRODUCTION Reinforced concrete is the most widely used construction material for bridges. The bridge decks are constantly subjected to concentrated traffic loads and are exposed to environment actions. Consequently, they deteriorate faster than other parts of the bridge. Also during winter, de-icing salts are used to keep the roads and bridges free from ice. De-icing salts, which are generally a mixture of sodium chloride and calcium chloride penetrate into the concrete and cause deterioration of the concrete structure and in particular, the steel reinforcement. These structures show excellent performance in terms of structural behavior and durability except for those zones that are exposed to severe environmental and mechanical loading (1). Rehabilitation of deteriorated concrete structures is a heavy burden also from the socio-economic viewpoint since it also leads to significant user costs. As a consequence, novel concepts for the rehabilitation of concrete structures must be developed. Sustainable concrete structures of the future will be those requiring just minimum interventions of only preventative maintenance with no or only little service disruptions. Over the last 10 years, considerable efforts to improve the behavior of cementicious materials by incorporating fibers have led to the emergence of Ultra-High Performance Fiber Reinforced Concretes (UHPFRC). These novel building materials provide the structural engineer with an unique combination of (a) extremely low permeability which largely prevents the ingress of detrimental substances such as water and chlorides and (b) very high strength, i.e., compressive strength higher than 150 MPa, tensile strength higher than 10 MPa and with considerable tensile strain hardening (up to more than 2‰ of strain) and softening behavior (with fracture energy of more than 15'000 J/m2). In addition, UHPFRC have excellent rheological properties in the fresh state allowing for easy casting of the self-compacting fresh material with conventional concreting equipment (2). Consequently, UHPFRC has an improved resistance against severe environmental and mechanical loading thus providing significantly improved structural resistance and durability to concrete structures. This paper presents an original concept for the rehabilitation of concrete structures. The concept is described and validated by means of four applications. Finally, two case studies were performed. In the first case study, the use of UHPFRC for rehabilitation of existing bridges was theoretically applied on a bridge deck slab. An existing bridge with insufficient durability for the deck slab and deteriorated edge beams was chosen as a reference bridge. In second case study, a comparison was made between an industrially produced bridge alternative and a reference composite bridge, conventionally produced with a cast in-situ normal strength concrete bridge deck slab. The new alternative bridge solution considered of main steel girders and prefabricated normal strength bridge deck elements joined and covered with UHPFRC.

2D representation of life cycle greenhouse gas emission and life cycle cost of energy conversion for various energy resources

We suggest a 2D-plot representation combined with life cycle greenhouse gas (GHG) emissions and life cycle cost for various energy conversion technologies. In general, life cycle assessment (LCA) not only analyzes at the use phase of a specific technology, but also covers widely related processes of before and after its use. We use life cycle GHG emissions and life cycle cost (LCC) to compare the energy conversion process for eight resources such as coal, natural gas, nuclear power, hydro power, geothermal power, wind power, solar thermal power, and solar photovoltaic (PV) power based on the reported LCA and LCC data. Among the eight sources, solar PV and nuclear power exhibit the highest and the lowest LCCs, respectively. On the other hand, coal and wind power locate the highest and the lowest life cycle GHG emissions. In addition, we used the 2D plot to show the life cycle performance of GHG emissions and LCCs simultaneously and realized a correlation that life cycle GHG emission is largely inversely proportional to the corresponding LCCs. It means that an expensive energy source with high LCC tends to have low life cycle GHG emissions, or is environmental friendly. For future study, we will measure the technological maturity of the energy sources to determine the direction of the specific technology development based on the 2D plot of LCCs versus life cycle GHG emissions.

Comparison of building enclosures designed to the minimum requirements of the 2011 NECB

The objective of this study was to compare the life cycle costs of lightweight and thermally massive building enclosures designed to meet the prescriptive requirements of the 2011 National Energy Code of Canada for Buildings (NECB) in Edmonton, Alberta, Canada. Nine enclosure systems matched to three buildings (office, school, and apartment) were designed to meet the NECB requirements. Energy costs were estimated from local energy prices and hygrothermal analyses conducted using WUFI Plus. Construction and maintenance costs were estimated using “bids” from local contractors and RS Means cost data. Life cycle cost analysis (LCCA) was carried out and the enclosures were compared based on equivalent annual cost. LCCA demonstrated that the high initial cost of heavier materials is largely offset by greater durability and reduced sensitivity to moisture. Despite relatively low initial costs, EIFS on stud framing was shown to have very high life cycle costs if not properly maintained.

Sustainability assessment of renovation packages for increased energy efficiency for multi-family buildings in Sweden

In this paper, we propose a method for assessing renovation packages drawn up with the goal of increasing energy efficiency. The method includes calculation of bought energy demand, life-cycle cost (LCC) analysis and assessment of the building according to the Swedish environmental rating tool Miljöbyggnad (MB). In this way the methodology assesses economic, indoor environmental quality (IEQ) and specifically environmental aspects associated with energy demand of such packages from a sustainability point-of-view. Through MB, energy efficiency packages are placed in context with other necessary measures required to improve environmental performance in buildings, providing a consistent and systematic basis other than simply financial performance by which to compare capital improvements.The method is further explained and analyzed by applying it in three case studies. In each case study a multi-family building representing a typologically significant class in the Swedish building stock is considered, and for each building a base case and two renovation packages with higher initial investment requirement and higher energy efficiency are defined. It is shown that higher efficiency packages can impact IEQ indicators both positively and negatively and that packages reducing energy demand by approx. 50% have somewhat higher LCC. Identified positive IEQ impacts point to added value for packages that may not otherwise be communicated, while negative impacts identify areas where packages need to be improved, or where MB indicators may be referred to as specifications in procurement procedures.

A model for measuring complexity of automated and hybrid assembly systems

The demand for delivering product variety has been increasing. Increased product variety caused by product customization, personalization, evolution and changes in their manufacturing systems. Variety allows manufacturers to satisfy a wide range of customer requirements, but it can also be a major contributing factor to increased complexity of assembly. Complexity is generally believed to be one of the main causes of the present challenges in manufacturing systems such as lengthy and costly design processes, higher life cycle costs and the existence of numerous failure modes. Complex assembly systems are costly to implement, run, control and maintain. Assessing complexity of assembly helps guides designers in creating assembly-oriented product designs and following steps to reduce and manage sources of assembly complexity. On the other hand, reducing complexity of assembly helps lower assembly cost and time, improves productivity and quality and increases profitability and competitiveness. The complexity of assembly should be assessed by considering both products and their assembly systems. In this paper, a structural classification coding scheme has been used to measure assembly systems complexity. It considers the inherent structural complexity of typical assembly equipment. The derived assembly systems complexity accounts for the number, diversity and information content within each class of the assembly system modules. A domestic appliance drive assembly system is used to demonstrate the use of the classification code to calculate the assembly system complexity. The developed complexity metrics can be used by designers as decision support tools to compare and rationalize various automated assembly systems alternatives and select the design that meets the requirements while reducing potential assembly complexity and associated cost.

Which 'Greenness' Is Valued? Evidence from Green Condominiums in Tokyo

This paper analyzes the transaction prices of green buildings assessed on the basis of multiple green factors. Our theoretical model demonstrates that the initial green premium can be negative but becomes positive as the building ages if a green building has a higher life-cycle cost and a longer economic life. Our empirical analysis of green condominiums in Tokyo confirms this prediction. We additionally find that the longer-life design is associated with a price premium, but the use of renewable energy and recycled materials and water is associated with price discounts. The price discounts are interpreted as the capitalization of a greater life-cycle user cost.

복원가능 시스템 설계를 위한 복원도 할당

Most engineered systems are designed with high levels of system redundancies to satisfy required reliability requirements under adverse events, resulting in high systems' LCCs (Life-Cycle Costs). Recent years have seen a surge of interest and tremendous advance in PHM (Prognostics and Health Management) methods that detect, diagnose, and predict the effects of adverse events. The PHM methods enable proactive maintenance decisions, giving rise to adaptive reliability. In this paper, we present a RAP (Resilience Allocation Problem) whose goal is to allocate reliability and PHM efficiency to components in an engineering context. The optimally allocated reliability and PHM efficiency levels serve as the design specifications for the system RBDO (Reliability-Based Design Optimization) and the system PHM design, which can be used to derive the detailed design of components and PHM units. The RAP is demonstrated using a simplified aircraft control actuator design problem resulting in a highly resilient actuator with optimally allocated reliability, PHM efficiency and redundancy for the given parameter settings.

Integrating life cycle costs and environmental impacts of composite rail car-bodies for a Korean train

A coupled Life Cycle Costing and life cycle assessment has been performed for car-bodies of the Korean Tilting Train eXpress (TTX) project using European and Korean databases, with the objective of assessing environmental and cost performance to aid materials and process selection. More specifically, the potential of polymer composite car-body structures for the Korean Tilting Train eXpress (TTX) has been investigated. This assessment includes the cost of both carriage manufacturing and use phases, coupled with the life cycle environmental impacts of all stages from raw material production, through carriage manufacture and use, to end-of-life scenarios. Metallic carriages were compared with two composite options: hybrid steel-composite and full-composite carriages. The total planned production for this regional Korean train was 440 cars, with an annual production volume of 80 cars. The coupled analyses were used to generate plots of cost versus energy consumption and environmental impacts. The results show that the raw material and manufacturing phase costs are approximately half of the total life cycle costs, whilst their environmental impact is relatively insignificant (3–8%). The use phase of the car-body has the largest environmental impact for all scenarios, with near negligible contributions from the other phases. Since steel rail carriages weigh more (27–51%), the use phase cost is correspondingly higher, resulting in both the greatest environmental impact and the highest life cycle cost. Compared to the steel scenario, the hybrid composite variant has a lower life cycle cost (16%) and a lower environmental impact (26%). Though the full composite rail carriage may have the highest manufacturing cost, it results in the lowest total life cycle costs and lowest environmental impacts. This coupled cost and life cycle assessment showed that the full composite variant was the optimum solution. This case study showed that coupling of technical cost models with life cycle assessment offers an efficient route to accurately evaluate economic and environmental performance in a consistent way.

Icarus’ predicament: Managing the pathologies of overspecification and overdesign

The phenomenon of overspecification and overdesign is well known in all industries: developing features that are not needed by the customer causes excess development efforts, missed due dates, terminated projects and higher lifecycle costs. The paper defines the phenomena, exploring inherent causes and prescribes solutions for both business-to-business and business-to-customer industries. It presents illustrative cases of overspecification and overdesign, proposes a self-assessment to determine the severity of these phenomena in an organization and resolves the conflicts driving these phenomena. Solutions suggested include adapting Simon’s satisficer approach, resolving the marketing conflict by focusing on the 20% of features that account for 80% of the value, breaking the assumption that overspecification is beneficial for future growth potential, resolving the product manager’s conflict via a global system view, implementing the 25/25 principle, freezing and stabilizing the specifications, constraining developer time to eliminate spontaneous overdesign, and piecemeal feature launch.

Report: Risk factors associated with treatment of mixed municipal solid waste in the Indian context

Across India, all small and large urban local bodies (ULB) alike are grappling with the problem of municipal solid waste (MSW), which has reached critical dimensions because of, among others, rapidly increasing quantities and complex characteristics, inadequate regulation, lack of awareness, concern and cooperation on the part of the urban residents, limited resources for collection, transport and safe disposal, and limited expertise on the part of the ULBs. A number of ULBs have attempted to address the two-fold constraint of resources and land by setting up treatment plants under the premise of generating revenue and reducing liability of safe disposal. Over the last three decades, under the paradigms of converting 'waste to energy' and 'waste to wealth' various technologies have been tried out, however time and again it is seen that irrespective of the technology, MSW treatment plants run in to difficulties and/or close down. The issues do not pertain just to technology but are systemic and encompass project development, feedstock delivery system including quality and quantity, climate, high life-cycle costs, low value realization on outputs and adverse environmental and social impacts. With such a wide range of risk factors, experience has shown that the probability of manifestation of any one of them or a combination thereof at one or the other stages of the project is quite high. Investment in a mixed MSW treatment plant therefore can not deliver positive financial returns, rather it can become a non-performing asset without even guaranteeing the desired environmental and public health benefits. This paper therefore argues for the adoption of a robust, elastic and most forgiving option of sanitary landfill as a dependable and safe disposal system for MSW.

Fuel Cell Development for NASA’s Human Exploration Program: Benchmarking With “The Hydrogen Economy”

The theoretically high efficiency and low temperature operation of hydrogen-oxygen fuel cells have motivated them to be the subject of much study since their invention in the 19th century, but their relatively high life cycle costs have kept them as a “solution in search of a problem” for many years. The first problem for which fuel cells presented a truly cost effective solution was that of providing a power source for NASA’s human spaceflight vehicles in the 1960s. NASA thus invested, and continues to invest, in the development of fuel cell power plants for this application. This development program continues to place its highest priorities on requirements for minimum system mass and maximum durability and reliability. These priorities drive fuel cell power plant design decisions at all levels, even that of catalyst support. However, since the mid-1990s, prospective environmental regulations have driven increased governmental and industrial interest in “green power” and “the hydrogen economy.” This has in turn stimulated greatly increased investment in fuel cell development for a variety of commercial applications. This investment is bringing about notable advances in fuel cell technology, but as these development efforts place their highest priority on requirements for minimum life cycle cost and field safety, these advances are yielding design solutions quite different at almost every level from those needed for spacecraft applications. This environment thus presents both opportunities and challenges for NASA’s Human Exploration program.

Sustainability analysis of renewables for climate change mitigation

Carbon dioxide is a major greenhouse gas (GHG) responsible for climate change. The energy sector accounts for approximately 75 % of the total carbon dioxide emissions in the world. The main options for reducing carbon dioxide emissions in energy systems are energy efficiency, and utilization of renewable energy and nuclear energy. In the present global energy scenario, the share of modern renewables in the total primary energy use is marginal (about 4.5 %). This paper assesses the sustainability of renewables for the world using the criteria of life-cycle cost, net energy ratio, resource constraint and greenhouse gas emissions. Renewable options for electricity generation and hydrogen generation for vehicles are assessed on the basis of these criteria. Life-cycle assessment (LCA) is carried out using SimaPro 6 LCA software. For electricity generation the base case considered is thermal power generation using coal. The options considered are wind energy, solar photovoltaics and biomass gasification. For hydrogen production three methods based on renewables (photovoltaic (PV)-electrolysis, wind energy conversion systems (WECS)-electrolysis and biomass gasification) are compared with the steam methane reforming (SMR) method. The renewable-based technologies seem to be sustainable on the basis of all criteria except the high life-cycle cost. In some cases, e.g., in biomass-based systems, land availability may constrain sustainability. Biomass is likely to be a sustainable solution only if marginal/scrub lands can be used for biomass plantation with adequate yield. However, this option needs to be studied to see if the net energy ratio is greater than one. It is found that hydrogen production by photovoltaic-electrolyzer can be a non-renewable method at low load factor (~0.15) and PV module efficiency (10 %). However, this method is renewable for higher values of load factor and PV module efficiency. The framework developed in this paper can form the starting-point for sustainability analysis.

Impacts of aero-engine deteriorations on military aircraft mission's effectiveness

Abstract International political and socio-economic developments have led the armed forces of many countries to become more aware of how their increasingly-stringent financial budgets are spent. One major expenditure for military authorities is upon aero-engines, because in-service deterioration in any mechanical device, such as an aircraft's gas-turbine engine, is inevitable. Each deterioration has an adverse effect on the performance and shortens the reliable operational life of the engine, thereby resulting in higher life-cycle costs. For a military aircraft's mission-profiles, the consequences of an aero-engine's deterioration upon the aircraft's operational-effectiveness as well as its fuel consumption and life have been predicted in this project using validated computer-simulations. These help in making wiser management-decisions, so leading to the achievement of improved engine utilisation, lower overall life-cycle costs and optimal mission effectiveness for squadrons of aircraft.

Consequences of aero-engine deteriorations for military aircraft

Political and socio-economic increasingly-stringent restrictions have led the armed forces of democratic countries to become more aware of how their financial budgets are spent. One major expenditure for military authorities is upon aero-engine maintanence because in-service worsening performance of any mechanical device, such as an aircraft's gas-turbine engine, is inevitable. Each deterioration also shortens the reliable operational life of the engine, thereby resulting in a higher life-cycle cost (LCC). For a military aircraft's mission-profiles, the consequences of an aero-engine's deterioration upon the aircraft's operational-effectiveness, its fuel consumption and life have been predicted, in this project, using validated computer-simulations. These help in making wiser management-decisions, so leading to the achievement of improved engine-utilization, lower overall life-cycle costs and greater mission effectiveness for squadrons of aircraft.