Economic Performance Of System Research Articles

Optimal scheduling of a cogeneration system via Q-learning-based memetic algorithm considering demand-side response

An optimization scheduling method for cogeneration systems based on the Q-learning-based memetic algorithm (QMA) is developed to enhance the system's wind power absorption capacity and economical operation. First, an optimal scheduling model for cogeneration systems is constructed. The model integrates time-of-use electricity pricing and heating comfort into the demand side, fully exploiting the potential of demand-side response (DR) in power generation and heating. An additional heat source (AHS), which consists of an electric boiler and heat storage tank, is used to uncouple heat and power. In addition, a QMA algorithm is designed to find the optimal operating scheme for the cogeneration system. The Q-learning algorithm is introduced to dynamically adjust crossover and mutation parameters during the global evolution stage, improving the algorithm's search capability. The Taguchi method is utilized for algorithm parameter calibration. Finally, the simulation results under various operating scenarios are compared and analyzed, verifying the feasibility and effectiveness of the proposed method. The simulation results show that DR and AHS can improve the system's economic performance and wind power utilization rate. Compared with the IMA, IPSO, MA, and IABC algorithms, the QMA algorithm reduces the average economic cost by approximately 1.18 %, 2.23 %, 5.69 %, and 14.69 %, respectively.

The Role and Contribution of The New Institutional Economics In Economic System Performance

This study investigates new institutions' contributions and economic implications in current economic developments. This study uses a qualitative approach with a literature study method. The study illustrates key thought concepts and relevant works from figures such as Douglass North, Elinor Ostrom, Oliver Williamson, Ronald Coase, and Avner Greif through analysis of various reference sources, including books, journal articles, and other related publications. The results of the literature study show that New Institutional Economics has an essential contribution to understanding the role of formal and informal institutions in shaping economic behavior and Performance. Legal institutions, such as laws, regulations, and public policies, provide the framework for economic interactions, literature study results whereas informal institutions, such as norms, beliefs, and social networks, influence individual economic decisions. The importance of institutions and organizations in improving economic efficiency and overcoming problems arising in the economic system is also highlighted in this study. In the context of New Institutional Economics, institutions and organizations act as mechanisms for reducing transaction costs, resolving conflicts, and increasing trust and cooperation among economic actors. Its theoretical implications strengthen an understanding of how institutions and organizations can shape economic behavior and Performance. In contrast, its practical implications can provide direction for more relevant and effective public policies addressing economic and social problems.

Impact of heat recovery and thermal load control on combined heat and power (CHP) performance

This research assesses the energy efficiency and techno-economic viability of a Combined Heat and Power (CHP) system designed for a typical building that meets both its electrical (97 kWh/d) and thermal (92 kWh/d) loads. The CHP system comprises wind turbines (WT), photovoltaic panels (PV), batteries, micro gas turbines (MGT), and boilers, which are evaluated for their techno-economic performance. To enhance the system's efficiency and minimize energy wastage in CHP, two strategies, namely heat recovery (HR) from MGT and Thermal Load Control (TLC) for converting surplus renewable power generation into thermal energy, are implemented. Four case studies are conducted to analyze the impact of each strategy on the CHP system's performance. The optimization of hybrid renewable energy systems, considering the overall system's economic performance, is achieved through the integration of MATLAB and HOMER PRO. The study reveals that the incorporation of TLC and HR results in significant reductions in the Cost of Energy (COE), Net Present Cost (NPC), CO2 emissions, loss of Power Supply (LPS), and energy sizing while increasing the renewable fraction in the CHP system. Sensitivity analysis is performed on the capital cost of components, TLC, and HR variations, demonstrating their substantial influence on the economic performance of CHP. The cash flow results show that the integration of these two components reduces the system cost by 25 %. It is also shown that almost 70 % of the CC of the system is related to PV and batteries. The proposed strategies and findings provide valuable insights for enhancing the reliability and techno-economic evaluations of hybrid renewable.

Equalizing multi-temporal scale adequacy for low carbon power systems by co-planning short-term and seasonal energy storage

Power supply faces seasonal security risks due to the large seasonal volatility of renewable energy sources (RES) generation. Power systems with high shares of RES generation are more difficult to keep seasonal and daily/hourly supply adequacy at the same level. Therefore, this paper first addresses multi-temporal adequacy detail accounting for differences in RES output and timing of production, and demand. Then a planning approach is proposed for sizing short-term and seasonal energy storage accompanying with RES to achieve multi-temporal adequacy equilibrium. Unlike existing methods based on linking typical days or 8760-h simulations, the seasonal electricity adequacy constraints are captured by orderly clustering yearly net power curves, then the energy balance constraints are decoupled into long-term (i.e., seasonal) and short-term (i.e., hourly) energy balances. At the short-term scale, the robust optimization is used to address the uncertainty and randomness of wind and solar generation, in the same time realizing the coordination of short-term and seasonal energy storage. A modified column and constraint generation algorithm is used to solve the min-max-min model with binary variables. Finally, case studies are carried out on the Garver-6 system and the Northwest China Power Grid. The results demonstrate that the proposed planning method ensures multi-temporal scale adequacy equilibrium for high-RES power systems, and improving the planned system's economic performance.

Study on the thermodynamic and economic performance of power generation cycle with small temperature difference

The low thermal efficiency and low economic benefits of power generation systems under small temperature difference conditions have always hindered their practical operation. In order to explore effective ways to achieve performance optimization of thermodynamic cycle electrical power generating systems under small temperature difference conditions, this study constructs a static analysis model of an organic Rankine cycle with small temperature difference, selects six different commonly used refrigerants, and investigates the influence of key parameters on the thermodynamic and economic performance of the system using difference working fluids. The outcomes indicate that key parameters such as evaporation temperature and condensation temperature play a critical role in the thermodynamic and economic performance of the power generation system. For the working fluids, R227ea provides the highest net power output, while ammonia (R717) is the best performer in regard to system thermal efficiency and economic performance.

Technical-economic evaluation of various photovoltaic tracking systems considering carbon emission trading

Renewable energy generation plays a crucial role in mitigating global climate change and achieving carbon peak and carbon neutrality targets. Photovoltaic (PV) power is an important component of renewable energy generation. With China's commitment to meet its dual carbon targets on time, the application of PV tracking systems, which significantly increase the amount of PV power generated, has become a trend for the future. However, the suitability of PV tracking systems varies significantly between regions. This paper aims to assess and compare the technical and economic performance of PV systems using different PV tracking systems in six different latitude regions in China under the consideration of carbon trading. By utilizing the PVsyst software, the monthly/yearly unit electricity generation of different tracking systems in each region is calculated. Furthermore, the technical and economic performance of these systems is assessed by computing the levelized cost of electricity (LCOE), net present value (NPV), and discounted payback period (DPP) with and without carbon benefits, taking into account sensitivity analyses. The results indicate that the dual-axis tracking (DAT) system achieves the highest electricity generation, providing a gain of 17.94 %–31.52 % compared to the fixed-tilt (FT) system. The horizontal axis tracking North-South (HATNS) system and the tilted-axis tracking (TAT) system are probably the most economically viable systems in areas with high radiation levels, with NPV values 2.02 %–25.55 % and 6.44 %–19.45 % higher, respectively, compared to the FT system. The introduction of carbon benefits significantly increases the economic viability of all tracking systems.

Thermal and economical performances analyses of a desiccant wheels-assisted atmospheric water harvesting system used in humid climate regions

The thermal and economic performance of an atmospheric water harvesting system that uses four-stage desiccant wheels to pre-humidify processed air was analyzed. A vapor-compression refrigerator was used as the cold source. Two types of heat sources, i.e., heat pump and solar water heater, were considered, and their performance was evaluated. First, thermal performance of the system using different heat sources was analyzed under humid ambient conditions (relative humidity was 40–90 %, dry bulb temperature was 15–35 °C). The results showed that the water harvesting rate was 25.1–94.1 kg/h under these ambient conditions. When a heat pump was used, the water harvesting efficiency with heat recovery was 0.97–2.48 kg/kWh, and 2.41–4.59 kg/kWh when the solar water heater was used. The economic performance of the system was investigated by using diesel generators as the power source. To provide drinking water for 100 people, who consume 3–8 kg/day/person, as compared with bottled water sold in the market, the recovery period of the systems with heat recovery were 0.97–2.58 years and 0.34–0.91 years when the heat pump and solar water heater were used, respectively.

A comparative study on design and performance evaluation of Organic Rankine Cycle (ORC) under different two-phase heat transfer correlations

Organic Rankine cycle (ORC) is considered to be a good solution to the high-efficient recovery of low-grade heat for saving energy and reducing carbon emissions. As the core component, the heat exchanger plays a significant role in the thermo-economic performance evaluation of an ORC plant and its heat transfer correlations greatly influence the cycle performance. In this paper, 8 two-phase heat transfer correlations (4 flow boiling ones and 4 flow condensation ones) are utilized to design the plate-type heat exchangers, and a comparative study among different correlations is carried out. The result shows the designed evaporators are finitely affected by heat transfer correlations whereas the situation with the designed condensers is the opposite. The net output power is slightly influenced with a relative difference within 1.1% but the system's economic performance is significantly affected with the maximum relative difference of electricity production cost up to 11.2%. The environmental performance is hardly affected by correlations with the maximum relative difference of total greenhouse gas emission within 0.96%. This paper analyzed the performance variation of the ORC under different correlations and provided a guideline for designing heat exchangers and evaluating the off-design performance of ORC systems.

Thermal economy analysis and multi-objective optimization of a small CO2 transcritical pumped thermal electricity storage system

With expansion of application scale of distributed renewable energy, importance of researching small electricity storage system is increasing. Thermal economic performance of a small CO2 transcritical pumped thermal electricity storage system (SCT-PTES) is studied in this paper. NSGA-II optimization method and TOPSIS decision method are used to optimize system performance. This paper also proposes a small CO2 transcritical pumped thermal electricity storage coupled building heating system (STC-PTES-H) scheme. The system performance is also studied. Results show that: (a) When round-trip efficiency and LCOS of SCT-PTES are 26.93% and 0.3862 $/(kW·h), respectively, thermal economic performance is optimal. (b) When amount of electricity produced by renewable energy sources is 10 MW, LCOS of SCT-PTES is 0.2002$/(kW·h). (c) Correlation between thermodynamic performance and economic performance of system is fitted, and optimization time is reduced. It provides a theoretical basis for optimization of thermal economic performance of system. (d) Energy utilization of SCT-PTES-H can reach 97.66%. It makes better use of energy. This research provides technical support for application of SCT-PTES in distributed renewable energy power plants.

Optimal design of a novel hybrid renewable energy CCHP system considering long and short-term benefits

The combination of biomass and solar energy in the combined cooling heating and power (CCHP) system is conducive to reducing carbon dioxide emissions of the system. To improve the system's economic performance under the punishment of carbon tax, this paper optimizes the system from system design and operation strategies. A hybrid renewable energy CCHP system with shaft power distribution structure of an internal combustion engine (ICE) is proposed. By optimizing the shaft power distribution of ICE, the direct drive heat pump is realized, and the efficiency of the shaft power of ICE is improved. A double-layer optimization method considering the long and short-term benefits is proposed based on the system, fully improving the system economy in design and operation. The case study shows that the CCHP system reduces the annual cost by 40.37% and the CO2 emission by 88.93% compared with the separate production system. Compared with the non-shaft power distribution system, the maximum daily operation cost is saved by 557.11CNY. Compared with the hourly optimization method, the proposed optimization method based on total daily benefit reduces the annual cost by 7.73% and CO2 emission by 35.87%, and the utilization rate of the energy storage device is higher.

Energy and economic performance assessment of a solar-assisted regenerative vacuum membrane desalination system

Vacuum membrane water desalination is a promising technology for freshwater production with the advantages of low conduction heat loss and mass transfer resistance, compared to other membrane technologies. Such systems can be driven by solar thermal collectors for green water production, yet there is a lack of dynamic system simulations in the literature to comprehensively assess the energy and economic system performance and evaluate the impact of brine recirculation as a method of regeneration, especially under hot desert climates where solar resources are abundant, but freshwater resources are scarce (e.g., the northern coast of Egypt, considered as the case study here). In this study, a dynamic system simulation model is developed in TRNSYS, where a new “Type” is introduced for the vacuum membrane module. Initial sizing of the system with ∼20 % solar fraction resulted in annual average gained output ratio and specific thermal energy consumption of 2.51 and 133.5 kWh/m3, respectively, with levelized cost of water and payback period of 14.7 USD/m3 and 1.53 years, respectively. By increasing the solar collectors’ area from 8 to 16 m2, the levelized cost of water increased by 14.54 %. The storage volume was highly influential on the solar fraction, which increased by 101.39 % as the volume increased from 0.3 to 0.7 m3. Increasing the membrane area from 0.3 to 0.5 m2 increased the gained output ratio by 76.75 % while decreasing the levelized cost of water by 14.79 %. Internal heat regeneration through brine recirculation enhanced the system performance at lower recirculation ratios. Without recirculation, the levelized cost of water increased by 117.41 % and the system met the daily distillate water demand for only 90 days of the year.

Power, cooling, freshwater, and hydrogen production system from a new integrated system working with the zeotropic mixture, using a flash-binary geothermal system

The current paper proposes a new hybrid system based on a binary-geothermal system to generate power, cooling capacity, freshwater, and hydrogen. This system includes an internal integration of the organic Rankine cycle and ejector refrigeration cycle with zeotropic working fluids, proton exchange membrane electrolyzer, and reverse osmosis desalination unit. The system is analyzed by developing a precise model in the Matlab software, and then a multi-objective grey wolf optimization is employed to optimize the proposed system performance. The net present value, payback period, and sum unit cost of products are considered the system's economic performance criteria to study the system's feasibility for investment. Results indicate that the Isobutene-R114 provides the best net output power, and the R12-R114 combination has the best cooling performance. Also, the R12-R114 reports the best overall performance as the organic Rankine cycle working fluid. Based on optimization results, the exergy and thermal efficiency reached 17.84% and 34.24%, respectively. The system could provide 856.06 kW net output power, 2410.54 kW cooling capacity, 0.743 kg/h hydrogen, and 40.22 kg/s freshwater with a sum unit cost of 25.5 $.GJ−1, and the total profit and payback period of 6.82 $M and 3.76 years.

Efficiency Evaluation of Regional Environmental Management Systems in Russia Using Data Envelopment Analysis

The concept of eco-efficiency has recently become an issue of great importance due to the growing trend of environmental degradation, and many approaches based on Data Envelopment Analysis (DEA) are used in the literature to evaluate the environmental performance of economic systems. However, research to date has paid little attention to the possibility of extending the DEA approach to the problem of measuring the economic feasibility of eco-efficiency improvement. The main aim of this study is to evaluate the efficiency of investments focused on improving the eco-efficiency of the regional economy in Russia using the DEA approach. The various types of costs for environmental protection measures are considered as inputs and the annual decrease in specific environmental impacts of the regional economy are considered as outputs of DEA models. This is different from previous research, which generally focused on environmental efficiency only, omitting the integration of economic aspects in eco-efficiency measures. This study compares three different modifications of basic DEA models in the context of technical complexity and practical feasibility. The results show that the efficiency of regional environmental management in many Russian regions has a great potential for improvement. From a practical point of view, the Slack-Based Measure (SBM) model provides the most accurate results for policy applications. Unlike other ratings, the DEA-SBM model may stimulate an optimization of environmental protection spending and the introduction of technological and organizational eco-innovations.

Network dynamics, economic transition, and policy design\u2014an introduction

Network dynamics, economic transformation, and policy design are closely related phenomena that influence the performance of economic systems in a variety of ways. In this introductory paper, we set the stage for a series of excellent contributions addressing some still largely unexplored questions in this research field. At the core of our introduction, we provide a contextual structuration and classification of the contributions to this special issue. Finally, we address some contemporary issues that deserve some attention since they open up highly interesting opportunities for future research.

Control performance monitoring and degradation recovery in automatic control systems: A review, some new results, and future perspectives

This paper addresses control performance monitoring (CPM) and degradation recovering in automatic control systems. It begins with a re-visit of CPM techniques and a summary of the major limitations of the existing CPM methods. They are (i) deficit in assessing control performance degradation caused by different types of disturbances and environment uncertainties, (ii) incapability for predicting performance degradation, and (iii) deficiency of efficient performance degradation recovering methods. In order to meet increasing demands of next generation automatic control systems for higher system performance, novel CPM methods have been developed in recent years, including performance assessment of control systems with deterministic disturbances and uncertainties, prediction of control performance degradation, and recovery of control performance degradation. Some of these methods and algorithms are introduced in the second part of this paper. The basis of these methods is a so-called residual centred model of feedback control systems, which allows a unified handling of control, monitoring and diagnosis in feedback control systems corrupted by disturbances and uncertainties. The focuses of these methods are on (i) introduction of the loop performance degradation index for the assessment and prediction of performance degradation in automatic control systems, (ii) predictive detection and estimation of loop performance degradation, and (iii) a data-driven performance degradation recovering scheme. The paper is concluded by a short summary of three future perspective topics, (i) prediction of economic system performance monitoring and estimation, (ii) reinforcement learning aided system performance recovery, and (iii) CPM digital twin.

Application of Economic Model Predictive Control in Integrated Energy System

Due to the uncertainty of the energy supply and the power demand, the stability and economic performance of the integrated energy system has become a key problem. In this paper, economic model predictive control with augmented model was directly applied to optimize the performance index while responding power demand. Based on the prices of power and hot water, the economic objective function was designed and two modes of operation of heating have been studied which include providing domestic hot water and space heating. The simulation result shows, compared with traditional model predictive control, economic model predictive control could improve economic performance of system by 20% while providing domestic hot water, and showed similar performance while working on space heating.

Multi-objective two-stage adaptive robust planning method for an integrated energy system considering load uncertainty

An integrated energy system (IES) is considered as an effective approach to reduce carbon emissions, lower energy supply costs and increase system flexibility. As numerous energy conversion and storage devices with various features have been developed, determining their types and capacity size and optimizing the synergic action of all selected energy devices under load uncertainty have become challenging issues during the planning and designing of a new IES. To address these issues, a load uncertainty model is constructed by integrating the regional equivalent standard building-integrated load prediction method, the robust uncertainty set method and the fuzzy C-means clustering algorithm. Based on this uncertainty model, this paper proposes a planning method that incorporates the fuzzy multi-objective decision and two-stage adaptive robust optimization methods for handling these challenging issues. The multi-objective decision method enables comprehensive optimization based on the system's economic performance, carbon emissions and grid integration level. The two-stage adaptive robust optimization method aims to optimize the single-objective problem transformed by the multi-objective decision method. The planning method is implemented in an industrial park in the Baoding City of China. The influence of load budget uncertainty, annual load growth rate and energy purchase price is then investigated. The results show that the load budget uncertainty and annual load growth rate only affect the optimal capacity size of the selected devices, whereas the energy purchase price influences both the optimal device types and their capacity size. The optimal capacity size remains constant when the load budget uncertainty exceeds 3. This study provides a methodology to select the suitable device types and determine their capacity size for IES under load uncertainty, which will benefit the design of a new IES.

Performance analysis and optimization of a cold standby system subject to [formula omitted]-shocks and imperfect repairs

This paper analyzes and optimizes the economic performance of a cold standby system subject to δ-shocks and imperfect repairs. Specially, the system consists of two components with different reliability characteristics. It is assumed that shocks arrive according to a Poisson process. When a component is active during operation, it will fail whenever the interarrival time between successive shocks is less than a threshold influenced by the number of repairs performed on this component. For reliability analysis, geometric process models are utilized to characterize the lifetime and repair time of the active component subject to δ-shocks and imperfect repairs. Using the supplementary variable method, some reliability measures of the system are obtained. Moreover, an explicit expression for the long-run cost per unit time is derived to quantify the system's economic performance. Finally, the optimal repair policy is determined based on this economic performance measure, and a sensitivity analysis is conducted to provide managerial insights for the efficient operation of such a system.

Operation and Sensitivity Analysis of a Micro-Scale Hybrid Trigeneration System Integrating a Water Steam Cycle and Wind Turbine under Different Reference Scenarios

Renewable energy sources, such as solar, wind, biomass, and geothermal energy, are being more and more adopted in small and micro-scale distributed generation systems. In this context, different hybrid configurations and layouts that may adopt, lead to different energy and economic performance of energy generation systems. In micro-scale applications, biomass and solar energy sources are more frequently investigated in literature compared to other combinations as biomass and wind energy. The analysis of the performance of a novel small-scale trigeneration system is presented in this paper. The system includes biomass boiler, water steam turbine, absorption chiller, and wind turbine, and it is linked to the electric grid by means of a bidirectional connection, allowing to the store virtually the electrical energy produced in excess, and use when needed. For the proposed system, a zootechnical farm and a residential building are considered as case study, including different scenarios for the reference energy system. The Transient System Simulation (TRNSYS software is used to model, simulate, and investigate the system performance under realistic operation conditions. Energy and economic performance of the system is assessed by means of a daily, weekly, and yearly analysis. The effect of the main design parameters, as steam and wind turbine power on the system performance, is investigated by means of a sensitivity analysis. The investigations show that the Simple Pay Back time of the proposed system is below 6 years, when the biomass is free, capacities of steam and wind turbines lower than 4 kW are selected, and a reference system with a natural gas boiler and electrical grid is considered. The system allows one to achieve satisfactory energy and economic performance under the considered conditions, when a proper design of the system component capacities is adopted.

ВЕКТОРНАЯ МОДЕЛЬ МНОГОКРИТЕРИАЛЬНОЙ ОЦЕНКИ

To assess the performance of economic systems, criteria and performance indicators are used that show the degree of achievement of the desired performance result. To characterize complex systems in most real cases, one criterion is not enough. Therefore, several criteria are used to comprehensively characterize the system. The multi-criteria problem raises the problem of matching individual criteria when used together. There are many ways to select alternatives in the face of multiple decision criteria. This article discusses the multi-criteria comparison of objects with Pareto dominance, vector estimates with arbitrary non-negative coordinates of vectors. The advantages of vector estimates in comparison with average estimates are considered. In this work, three important theorems of multi-criteria estimation are proved. The theorems define the conditions for the equivalence of three options for comparing objects by a variety of attributes: 1) arithmetic mean values; 2) the lengths of the corresponding vectors; 3) scalar products of vectors. As the research results, the application of the developed methods for aggregating the quality indicators of the educational process into a single assessment is shown. The following indicators of the educational process were used: coefficient of diligence, coefficient of interest, coefficient of difficulty of mastering the studied material, assessment of academic performance. A four-criteria optimization problem is formulated. It is shown that the objective function reaches its extreme value at the point that is as close as possible to the point of the optimal solution of the formulated problem. The issues of multi-criteria assessment developed in the article can find application in the management of the educational process in the formation of individual trajectories of trainees, in the tasks of working with the personnel of firms and organizations (selection, training, retraining), in assessing the quality of products and in other areas of activity.