Operating Cost Rate Research Articles

The Effects of Increased Distance Travel on the Operating Costs of Freight Truck Vehicles

Transportation industry is an important part of most countries’ economies with significant effects on productivity and social welfare. However, refrigeration has dramatically altered global food transportation efficiencies in the cold supply chain. Hence, a key factor to optimize transportation is by lowering operational costs, with distance travel having a considerable impact. The paper examines how the operational costs of different truck classes is influenced by the distance travelled. The operating cost equation was utilized to make a comparison between vehicle operating costs and to assess how these costs change in relation to travel distance. The equation consists of influential parameters such as fuel cost, driver wage, and maintenance cost of a vehicle. The result showed that the operating cost rate varies among trucks of different classes. According to the results of the equation and effective parameter analysis, 18-ton trucks had the highest cost, followed by 5-ton trucks. This is due to fact that the cost is influenced by factors of travel distance, tolls, and fuel consumption. Furthermore, based on transportation costs, a green practice framework can be constructed to reduce truck costs for each delivery while reducing CO2 emissions to the environment. By taking into account transportation cost factors in the framework of green practices, effective and practical information can be generated such as product delivery schedules to customers and better routes to improve business performance. Finally, effective transportation management can improve inventory flow by enhancing warehouse efficiency, reducing overall lead time, and saving on storage costs.

Transesterification of Persea americana seed oil to methyl ester using bio-based heterogeneous catalyst: Optimization and techno-economic analysis

The techno-economic analysis of producing biodiesel from agrarian wastes at optimal condition was carried out. The acid activated empty palm fruit bunch ash (AAEPFBA) catalyzed the methyl ester production. The AAEPFBA catalyst was synthesized from waste palm fruit bunch, and modified with phosphoric acid. The activation was best achieved by adding H3PO4 acid in a ratio of 1:2 (g/ml). The modification of the catalyst increased the alkaline properties and surface area and decreased the particle size and adsorption energy. The process variables of temperature 61.9 °C, reaction time of 3.09 h, methanol/oil molar ratio of 10.2:1, catalyst concentration of 3.14wt%, and agitation speed of 321.54 rpm at a desirability of one gave an experimental optimal yield of biodiesel as 90.3%. Based on the experimental study, 3062 litres (2728 kg) of biodiesel was evaluated annually. The annual operating cost, payback period, and internal rate of return are ₦2201288, 1.5 years, and 7.6%, respectively. The sensitivity analysis of oil purchase cost, biodiesel selling price, and labour cost on Return on investment, PBP, IRR, and Net present value were investigated. In this study, the relative biodiesel selling price is a determinant of the profitability of producing avocado pear seed oil methyl ester. The overall results show that investors can embark on biodiesel production using avocado pear seed oil, and AAEPFBA as feedstocks.

Application of Entropy Weight TOPSIS Method in Financial Risk Assessment of Liquor Listed Companies

Taking 14 financial indicators of Shanxi Fenjiu from 2012 to 2022 as samples, this paper uses entropy weight TOPSIS method to establish a financial risk evaluation system from profitability, operating ability, debt paying ability and development ability, and makes a comprehensive evaluation on the financial risk status of Shanxi Fenjiu in recent 11 years. The results show that profitability and operating ability are the first-level indicators that have the greatest impact on financial risk. From the perspective of sub-divided second-level indicators, operating cost rate in profitability, inventory turnover rate in development ability, asset-liability ratio in debt repayment ability, and the proportion of total assets growth rate in development ability have the highest impact on the ranking results. The overall trend of financial risk of Shanxi Fenjiu in the past 11 years has shown "M" type fluctuations, and the recent risk level is relatively low. In order to effectively prevent risks, Shanxi Fenjiu should effectively control the sales expenses, balance the volume and price of products, improve the turnover efficiency, maintain the brand image, maintain the asset-liability ratio within a reasonable range, and strive to resolve the financial risks from the root, so as to enhance the financial value. The research results have certain reference significance for liquor listed companies to formulate reasonable financial management plan.

Does digital transformation improve the firm’s performance? From the perspective of digitalization paradox and managerial myopia

Following the resource-based view and upper echelons theory, we use data on Chinese A-share listed companies from 2013 to 2020 to investigate the effect of digital transformation on total factor productivity and firm performance, as well as the moderating effect of managerial myopia. The results show that digital transformation can significantly increase total factor productivity but decrease firm performance by increasing the operational cost rate, reducing total asset turnover, and increasing management expenses. Managerial myopia can significantly amplify the negative effects of digital transformation. Low- or high-digital transformation is not conducive to firm performance, whereas median-digital transformation can significantly improve firm performance. The more labor-intensive enterprises, the more negative the effect of digital transformation on firm performance. This study enriches and supplements the resource-based view and upper echelons theory and extends the research on the economic consequences of digital transformation based on the context of developing countries.

The Effect of Financial Digital Transformation on Financial Performance: The Intermediary Effect of Information Symmetry and Operating Costs

The ability of A-share listed companies to adhere to the digital economy and achieve long-term corporate benefits amidst an uncertain external environment through financial digital transformation remains a crucial concern for entrepreneurs and scholars. The objective of this study was to scrutinize the effect of financial digital transformation on financial performance among 2566 of China’s A-share listed companies in the hopes of providing informative recommendations for businesses that are currently undertaking or planning to undertake financial digital transformation. To investigate the mechanism by which financial performance among A-share listed companies was influenced by digital transformation, a panel data regression model was utilized. The findings suggest that, first and foremost, financial digital transformation significantly boosts corporate financial performance for A-share listed companies, and this enhancement is sustainable over time. For every 1% growth in financial digital transformation, corporate financial performance improves by 1.1%. Corporate financial performance is projected to improve by 29.8% during the next three financial years. Secondly, information symmetry and operational expenses function as intermediaries in the financial digital transformation process that affects firm financial performance. For every 1% increase in financial digital transformation, the information symmetry level of firms grows by 15.1%, while the operational cost rate declines by 0.8%. Thirdly, information disclosure and operating costs play a chained intermediary role. Every 1% increase in the level of information symmetry reduces the operating cost rate by 2.3%. Fourthly, in comparison to enterprises in eastern provinces, businesses located in central and western provinces are better positioned to improve their financial performance by undertaking a financial digital transformation.

Two-stage stochastic programming with robust constraints for the logistics network post-disruption response strategy optimization

Logistics networks (LNs) are essential for the transportation and distribution of goods or services from suppliers to consumers. However, LNs with complex structures are more vulnerable to disruptions due to natural disasters and accidents. To address the LN post-disruption response strategy optimization problem, this study proposes a novel two-stage stochastic programming model with robust delivery time constraints. The proposed model jointly optimizes the new-line-opening and rerouting decisions in the face of uncertain transport demands and transportation times. To enhance the robustness of the response strategy obtained, the conditional value at risk (CVaR) criterion is utilized to reduce the operational risk, and robust constraints based on the scenario-based uncertainty sets are proposed to guarantee the delivery time requirement. An equivalent tractable mixed-integer linear programming reformulation is further derived by linearizing the CVaR objective function and dualizing the infinite number of robust constraints into finite ones. A case study based on the practical operations of the JD LN is conducted to validate the practical significance of the proposed model. A comparison with the rerouting strategy and two benchmark models demonstrates the superiority of the proposed model in terms of operational cost, delivery time, and loading rate.

An Operating Cost Calculation Method for Integrated Energy Systems Considering Components Failures

As the energy problem becomes more and more serious, the integrated energy system (IES) becomes a hot research direction in the energy field. Existing studies have not considered the impact of component failures on the operating costs of IES. Therefore, people tend to underestimate operating costs, and accidents such as interruptions in energy supply may occur because of an over-optimism operation strategy. This paper proposes an operating cost calculation method to evaluate the normal and failure states of IES. Moreover, the impact of component failures on the IES is determined based on the incremental operating cost and failure rate. The results verify that the operating cost considering component failure significantly increases compared to the normal calculation method.

Effect of Chinese Currency Appreciation on Investments in Renewable Energy Projects in Countries along the Belt and Road

Foreign investment in renewable energy generation projects is a critical part of the Belt and Road Initiative. Under the background of the market economy, the electric energy will participate in power market competition among the countries along the line, and the sales revenue will be settled in the local currency. The exchange rate of the countries along the Belt and Road fluctuates frequently and widely, thereby posing significant risks to the investment income of the projects. To address this problem, this paper proposes the concept of Ek as the effective exchange rate expressed by the on-grid price, investment cost per kilowatt electricity generation equipment, and annual operating cost rate of unit power generation capacity. Moreover, this paper presents a model of power generation cost, income, and earning expressed by the real exchange rate. The flexibility formula of the fluctuation of power generation cost, income, profit, and internal rate of return relative(IRR) to Ek is derived, and the effect of exchange rate level and fluctuation on projects is analyzed. With the wind power projects invested by China in Pakistan taken as an example, the trend during the entire life cycle is calculated. The changes in net profit rate, IRR, and levelized cost of energy (LCOE) are calculated under Chinese currency appreciation of 10%, 20%, and 35% and 5% and 10% reduction of investment cost per unit. As the Chinese currency appreciates and the project IRR declines significantly, LCOE decreases slightly, but this decrease is not sufficient to compensate for the losses caused by the decline in IRR. The following effective measures are proposed to deal with the exchange rate fluctuation of foreign renewable energy generation projects: building energy Internet, reducing project cost, and using Chinese currency as the settlement currency. In this paper, a solution is provided for investments in renewable energy projects in regions where exchange rates fluctuate greatly.

A c/μ‐Rule for Job Assignment in Heterogeneous Group‐Server Queues

We study a dynamic job assignment problem in queueing systems with one class of Poisson arrivals and K groups of heterogeneous servers. A scheduling policy prescribes the job assignment among servers in each group at every state n (number of jobs in the system). Our goal is to obtain the optimal policy to minimize the long‐run average cost, which involves the increasingly convex holding cost for jobs and the operating cost for working servers. This problem has wide application scenarios in operations management, such as job scheduling in manufacturing systems, packet routing in communication systems, and staffing in service systems. We prove that the optimal policy has monotone structures and quasi bang–bang control forms. Specifically, we discover that the optimal policy is governed by the marginal cost rate c − μG( n), where c is the operating cost rate, μ is the service rate, and G( n) is called the perturbation realization factor at state n. Under the condition of scale economies which can be guaranteed by any increasingly concave operating cost in μ, we prove that the optimal policy obeys a so‐called c/ μ‐ rule: Servers with a smaller c/ μ should be occupied by jobs with higher priority. Optimality of multi‐threshold type policies is further proved when the c/ μ‐rule is applied. Our c/ μ‐rule in group‐server queues can be viewed as a counterpart of the famous cμ‐rule in polling queues, which both significantly reduce the complexity of optimization problems. By utilizing these optimality structures, we also develop computational‐efficient algorithms to determine the optimal policy numerically. Simulation experiments demonstrate the good scalability and robustness of the c/ μ‐rule, which are important for managerial practice.

Simulation and exergoeconomic analysis of the syngas and biodiesel production process from spent coffee grounds

The integrated production of biofuels from agro-industrial wastes is increasing around the world. The thermodynamic performance and economic analysis of these processes have become topics of interest given the need to reduce the cost of biofuels and their impact on the environment. This study develops a simulation of the production process of syngas and biodiesel from spent coffee grounds, and an exergoeconomic analysis that mainly determines the exergy destruction rate, the investment and operational cost rate, and the exergy destruction cost rate at component level and for the overall system. The total investment cost for the integrated process resulted in 13.2 million dollars. The specific cost of syngas and biodiesel from spent coffee grounds were estimated in $0.36/kg and $0.71/kg, respectively. The results show that the drying process including the air heating for the pretreatment of the biomass had an exergy destruction rate of 11,463 kW and was responsible of the 92% of the overall exergy destruction cost rate. An increment of the dead state temperature reduced the specific cost of syngas and biodiesel in 17% and 8%, respectively. Future studies should focus on the exergoeconomic optimization of the drying process of biomass in order to minimize the operational costs.

Capacity optimization of hybrid energy storage system for flexible islanded microgrid based on real-time price-based demand response

The islanded microgrid (IMG) is universally accepted as an important method to solve the island power supply problem. The optimal capacity of the hybrid energy storage system (HESS) is necessary to improve safety, reliability, and economic efficiency in an IMG. To improve the IMG ability to deal with uncertainty, this paper proposed a flexible islanded microgrid (FIMG) model with real-time price (RTP)-based demand response (DR). Through RTP to guide users’ electricity consumption behaviors more in line with renewable energy sources (RES) output law, the capacity allocation of the HESS was optimized and the system had sufficient flexibility in each scheduling period. In this paper, two decision variables of the HESS, the number of lead-acid batteries and supercapacitors, were determined based on the objective of comprehensive operating cost (COC) and flexibility insufficiency rate (FIR) minimization. Firstly, the non-dominated sorting genetic algorithm II (NSGA-II) was devoted to obtaining the Pareto set that satisfies the FIMG day-ahead scheduling. Then, both the loss of produced power probability (LPPP) and the loss of power supply probability (LPSP) corresponding to each Pareto solution were gotten based on the real-time dispatch strategy. Finally, taking COC, FIR, LPPP, and LPSP as evaluation indicators, the improved Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) was applied to select the optimal solution from the Pareto set. In the case study, a FIMG on an island in Guangdong province was analyzed and discussed. By studying typical days in winter and summer of the FIMG, the superiority of the proposed model and methods was verified.

Energetic, Exergetic, Environmental, and Economic Assessment of a Cascade Refrigeration System Operating with Four Different Ecological Refrigerant Pairs

In this work, a cascade refrigeration system operating with four different ecological refrigerant pairs was modeled. This system uses R744 (Carbon dioxide) in the low-temperature cycle and operates with R290 (propane), R1234yf (2,3,3,3-tetrafluoropropene), R152a (1,1-difluorethane), and R717 (ammonia) in the high-temperature cycle. Energetic, exergetic, environmental, and economic performance of the cascade system was investigated to determine the most appropriate ecological refrigerant couple. The parameters used in each mentioned performance were COP (Coefficient of Performance), [Formula: see text] (Exergy Efficiency), TEWI (Total Equivalent Warming Impact), ECOP (Ecological coefficient of performance), and [Formula: see text] (Total plant cost rate), respectively. The results showed that the cascade refrigeration system operating with R744/R717 provided the best performance for the thermodynamic conditions analyzed, presenting a COP of 2.10, [Formula: see text] of 56.9%, [Formula: see text] of 24 334 USD/year, ECOP of 4.86, and TEWI of 25.67 tons of CO2. Finally, evaluating the total plant cost rate of this cascade system, it was noted that the capital and maintenance cost rate [Formula: see text] corresponds to 89.1% of the [Formula: see text] value, the operational cost rate [Formula: see text] corresponds to 10.27% of the [Formula: see text] value and the environmental cost rate [Formula: see text] corresponds to 0.63% of [Formula: see text].

Thermo-economic and environmental analysis of a small capacity vapor compression refrigeration system using R290, R1234yf, and R600a

Abstract In recent years, the international community has been continuously encouraged the development of new vapor compression refrigeration systems, that operate with ecological refrigerants, to replace systems with non-ecological refrigerants. In view of this need, this paper presents a mathematical model of a small cooling capacity vapor compression refrigeration system. This model was used to design an energy-efficient system, with low cost, that operates with the most appropriate ecological refrigerant in terms of overall environmental impact, focusing the refrigerants R290, R600a, and R1234yf. The environmental analysis was performed based on TEWI (Total Equivalent Warming Impact), while the thermo-economic analysis was performed based on COP (Coefficient of Performance), ηexergy (Exergy Efficiency), and C ˙ total (Total plant cost rate). Also, the contribution of each individual cost rate related to C ˙ total was identified. A similar procedure was also carried out on the total exergy destruction. The thermo-economic and environmental analysis indicated that the system with R290 has higher energy, exergy, environmental, and economic performance among the evaluated systems for the studied thermodynamic conditions. Thus, the system with R290 is the most suitable to replace systems with R134a. Finally, analyzing the three cost rates related to C ˙ total in each system, it was noted that the operational cost rate was the most relevant cost, and it corresponds to more than 73% of the C ˙ total value, while the penalty cost rate due to carbon dioxide emission was the least relevant cost, corresponding to less than 2.60% of the C ˙ total value.

Scheduling Preventive Maintenance Considering the Saturation Effect

During the useful life period of a costly system, it has been a common practice to perform imperfect preventive maintenances (PMs) with the purpose of failure prevention and useful life extension. Nevertheless, a system cannot be restored to an as-good-as-new state even though the imperfect PM actions are performed with a high frequency. This is known as the saturation effect and it is commonly overlooked in the existing literature. Motivated by a PM problem in a manufacturing company, this study proposes two PM models to capture the dynamics of the saturation effect. The first model divides the system deterioration into recoverable damage and irreversible intrinsic fatigue. The PMs are assumed to be effective only in healing the first type of damage. When the intrinsic fatigue for some complex systems cannot be well defined, we propose another model that generalizes the existing virtual age models by allowing the proportion of virtual age reduction to depend on the PM frequency. The long-run average costs of the two models are derived, and optimization of the cost models is investigated. The proposed PM models are then applied to two types of mechanical systems in the manufacturing company. The case study shows that ignorance of the saturation effect will make inferior maintenance policy that incurs substantial losses. The proposed models are also shown to be robust in the sense that the parameter estimation errors cannot significantly increase the system operational cost rate.

Environmentally friendly disposition decisions for end-of-life electrical and electronic products: The case of computer remanufacture

Increasing concerns about environmental sustainability strategies, take-back laws and natural resource limitation has highlighted the impact of disposing end-of-life (EOL) electrical and electronic products. To cope with this challenge, manufacturers have integrated reverse logistics into their supply chain or chosen to outsource product recovery activities to third parties. This research studies the remanufacturing processes of reusable products and parts, cost and demand of remanufactured products and parts to determine return quality thresholds during multiple production period. We present a general framework for a third party remanufacturer, where the remanufacturer has the alternative of supplying parts to external suppliers or bringing the disassembled parts to ‘as new’ conditions. The problem is formulated as a mixed integer non-linear programming (MINLP) problem, where with proposed discretization, the problem turns into a quadratic mixed integer programming (QMIP) problem. Finally, the impact of the quantity of returns, operational cost and upper bound disposal rate using a case numerical study of a personal computer (PC) remanufacturing facility has been studied.

Exergy and thermoeconomic analysis of cream pasteurisation plant

Cream is a milk derivative comparatively rich in fat, present in the form of emulsion of fat in skimmed milk, and acquired by physical extraction from raw milk with the help of centrifugal separator. The cream with variable fat content (10–40%) is commonly employed as an ingredient to traditional or modern desserts. It is also used in the production of value-added milk products such as butter and ghee apart from regular cooking applications. The pasteurisation, being an important safety requirement of milk food products, is usually materialised by heating the milk cream at a temperature of 90 °C for a period of one second. In the current work, thermodynamic and thermoeconomic derivatives in combination with all available constraints have been determined for high temperature short-time cream pasteurisation plant. The energy and exergy efficiency of cream pasteurisation plant was determined to be 86.88% and 66.11%, respectively. The cumulative value of energy destruction and exergy demolition in subunits of cream pasteurisation plant was estimated to be 93.88 kW and 11.39 kW, respectively, which mainly ascribed to complete enzymatic denaturation of fluid cream. The overall operating cost rate of complete cream pasteurisation plant was calculated as 1649.10 Rs./H, 22.02% portion of which was associated with electrical energy consumption. Further, the cost rate of exergy degradation for chilling and cooling activities was reported as 617.57 Rs./H and 357.55 Rs./H, respectively. The exergoeconomic factors of heating (14.75%) and chilling activity (0.82%) articulated that capital investment was dominant in the former while thermal degradations were enunciated most flagrant in latter.

Energy, exergy and exergoeconomic analysis of high temperature short time milk pasteurisation plant

India produces 19.54% of the total annual milk production of the entire world (819 MT) with yearly rise of 3.6%. The thermal and electrical energies consume 10%-20% of manufacturing cost of pasteurised milk. In the present work, energy, exergy and exergoeconomic appraisals of skim milk pasteurisation plant have been performed. The exergy gauge registered an exergy efficiency of 68.84% with 35% exergy recovery potential. The analysis revealed that relative irreversibility ratio of regeneration-3 (7.87%) was higher than regeneration-2 (4.24%) followed by regeneration-1 (1.25%), which represented their excellent sustainability characteristics. The thermoeconomic analysis has identified the immensity of exergoeconomic indices such as total operating cost rate, exergoeconomic factor and percentage relative cost difference. The exergoeconomic factor was reported to be most significant in holding coil (62.45%), heat exchanger (49.25%) and regeneration-1 (20.18%). The high and low values of exergoeconomic factor magnify the role of capital investment and thermodynamic inefficiencies respectively.

Exergoeconomic analysis and optimization of a hybrid system based on multi-objective generation system in Iran: a case study

The present work aims to study a multi-objective generation system based on renewable solar and wind energy that has been selected according to the climatic conditions of the area under study, i.e. Bandar Abbas, Iran. In general, the system includes six different sections such as solar cycle, single effect absorption chiller, Rankine cycle with ammonia–water fluid, wind turbine, electrolyzer, and multi-stage flushing desalination. First, the system is investigated in terms of thermodynamic and exergy principles. Then, exergoeconomic analysis with specific exergy costing method (SPECO) is carried out based on the concepts of product, fuel, and cost balancing. The sensitivity analysis investigates the effect of decision parameters on energy and exergy efficiencies. Finally, single-objective optimization is analyzed using conjugate method and the multi-objective optimization is analyzed using genetic algorithm. Results show that, based on multi-objective optimization, isentropic efficiency of turbine is 81%, isentropic efficiency of pump is 77%, pressure ratio of Rankine cycle is 40.32, solar cycle mass flow is 0.8 k/s, outlet temperature of boiler is 113.62°C, exergy efficiency is 32.88%, and operating cost rate is 8.45 dollars per hour. Using multi-objective optimization, operating cost rate decreases by 22.6% and exergy efficiency increases by about 5.31%.

Performance Comparison of Real-Time Yard Crane Dispatching Strategies at Nontransshipment Container Terminals

Yard crane operations are often a bottleneck at a container terminal. This paper aims to investigate the effects of various real-time yard crane dispatching strategies on operational cost and gross crane rate (GCR) for nontransshipment container terminals. A general cost estimation model is introduced to incorporate the detailed costs incurred during container handling process within terminal area. The formulas of container handling related parameters are mathematically derived to validate the simulation model. Results reveal that the common nearest truck first served strategy yields the lowest operational cost but the lowest GCR. On the other hand, earliest YT strategy achieves the highest GCR at the expense of higher operational cost with more vessel calls, while nearest YT strategy produces the highest GCR and is the second economical with fewer vessel calls. Under any of the proposed yard crane dispatching strategies, the strategy that separately stacks import and export containers into different blocks outperforms the scattered stacking strategy in terms of GCR, although no distinct cost advantage is obtained. The results provide fundamental insights into the connection between real-time yard crane dispatching strategies and operational performance at manually controlled nontransshipment container terminals.

Analysis of an integrated cryogenic air separation unit, oxy-combustion carbon dioxide power cycle and liquefied natural gas regasification process by exergoeconomic method

Exergoeconomic and sensitivity analyses are performed on the integrated cryogenic air separation unit, oxy-combustion Carbon dioxide power cycle and liquefied natural gas regasification process. Exergy destruction, exergy efficiency, cost rate of exergy destruction, cost rate of capital investment and operating and maintenance, exergoeconomic factor and relative cost difference have been calculated for the major components of the process. The exergy efficiency of the process is around 67.1% and after mixers, tees, tank and expansion valves the multi-stream heat exchanger H-3 have the best exergy efficiency among all process components. Total exergy destruction rate of the process is 1.93×107kW. Results of exergoeconomic analysis demonstrates that maximum exergy destruction and capital investment operating and maintenance cost rate are related to the multi-stream heat exchanger H-1 and pump P-1 with the values of 335,144 ($/h) and 12,838 ($/h), respectively. In the sensitivity analysis section the effects of the varying economic parameters, such as interest rate and plant life time are investigated on the trend of the capital investment operating and maintenance cost rate of the major components of the process and in another cases the effect of the gas turbine isentropic efficiency on the exergy and exergoeconomic parameters are studied.