Investigation the integration of heliostat solar receiver to gas and combined cycles by energy, exergy, and economic point of views

Due to the high amount of natural gas resources in Iran, the gas cycle as one of the main important power production system is used to produce electricity. The gas cycle has some disadvantages such as power consumption of air compressors, which is a major part of gas turbine electrical production and a considerable reduction in electrical power production by increasing the environment temperature due to a reduction in air density and constant volumetric airflow through a gas cycle. To overcome these weaknesses, several methods are applied such as cooling the inlet air of the system by different methods and integration heat recovery steam generator (HRSG) with the gas cycle. In this paper, using a heliostat solar receiver (HSR) in gas and combined cycles are investigated by energy, exergy, and economic analyses in Tehran city. The heliostat solar receiver is used to heat the pressurized exhaust air from the air compressor in gas and combined cycles. The key parameter of the three mentioned analyses was calculated and compared by writing computer code in MATLAB software. Results showed the use of HSR in gas and combined cycles increase the annual average energy efficiency from 28.4% and 48.5% to 44% and 76.5%, respectively. Additionally, for exergy efficiency, these increases are from 29.2% and 49.8% to 45.2% and 78.5%, respectively. However, from an economic point of view, adding the HRSG increases the payback period (PP) and it decreases the net present value (NPV) and internal rate of return (IRR)

Bacterial Endocarditis and Periodontal Disease

Abstract: Bacterial endocarditis is the infection of inner lining of heart and /or heart valves. This disease is usually related to the presence of some pathogenic bacteria in mouth, digestive system or urinary tract. Most of the times, this infection happens in people with heart problems like the presence of prosthetic valves, history of previous endocarditis, some congenital heart defects and heart transplant. Some bacteria which are able to reach into blood and produce bacteremia are able to cause endocarditis in these patients. Some pathogenic bacteria in mouth may produce this disease after causing periodontal infection and reaching into bloodstream. Among these bacteria, some Gram positive cocci and Gram negative bacilli have important roles. To prevent this disease, it is recommended to consider oral hygiene and to receive antibiotic prophylaxis before some dental surgeries. Keywords: Keywords: Bacterial endocarditis, Periodontal disease, Bacteremia, Oral hygien

Techno-economic modelling, analysis and simulation of a water distribution system integrated with pump and autoclave components

Water distribution networks (WDNs), have a complex structure. Their least-cost design and simulation is therefore crucial to convey adequate quantities of water from sources to consumers using the most efficient way. The current research attempts to present an original approach to perform the technical and economic evaluation of a WDN integrated with an autoclave system. For this purpose, a mathematical modelling method is employed to investigate the techno-economic viability of the simulated water system under the effect of the system's design variables. The autoclave's minimum and maximum pressure values as well as the pump flow capacity rates are considered as the free variables of the system and then entered into the proposed analytical model. Afterwards, a tradeoff analysis among the primary components of the system, i.e., pump and autoclave cost has been performed. In the next step, an evaluation on the cost of energy was also carried out to demonstrate the cost variations according to the different pressure values. Results are indicative of the significant changes in the total system cost under the effect of the design variables. In the last stage of this paper, a sensitivity and graphical analysis of the decision variables was also performed to define the input parameters, thus determining the optimum maximum pressure of the autoclave system by which the total cost of the water system is minimized. The technical variables such as the autoclave volume and pump differential head were also investigated during the performed analysis

A new approach for performance assessment of parallel and non-bottleneck machines in a dynamic job shop environment

urpose: The current study aims to propose a new analytical approach by considering energy consumption (EC), maximum tardiness and completion time as the primary objective functions to assess the performance of parallel, non-bottleneck and multitasking machines operating in dynamic job shops. Design/methodology/approach: An analytical and iterative method is presented to optimize a novel dynamic job shop under technical constraints. The machine\u2019s performance is analyzed by considering the setup energy. An optimization model from initial processing until scheduling and planning is proposed, and data sets consisting of design parameters are fed into the model. Findings: Significant variations of EC and tardiness are observed. The minimum EC was calculated to be 141.5 hp.s when the defined decision variables were constantly increasing. Analysis of the optimum completion time has shown that among all studied methods, first come first served (FCFS), earliest due date (EDD) and shortest processing time (SPT) have resulted in the least completion time with a value of 20 s. Originality/value: Considerable amount of energy can be dissipated when parallel, non-bottleneck and multitasking machines operate in lower-power modes. Additionally, in a dynamic job shop, adjusting the trend and arrangement of decision variables plays a crucial role in enhancing the system\u2019s reliability. Such issues have never caught the attention of scientists for addressing the aforementioned problems. Therefore, with these underlying goals, this paper presents a new approach for evaluating and optimizing the system\u2019s performance, considering different objective functions and technical constraints

Technical and economic modelling and evaluation of a water distribution system equipped with an autoclave for industrial production applications

Purpose: The purpose of this paper is to investigate the autoclave-pump pressured water distribution system. Pressured water is used in many manufacturing processes, as a raw material or as a service fluid for different applications. Design/methodology/approach: The performances and the total installation costs of such systems are strongly related to its design and to its decision variables definition. The authors first identify the independent variables (i.e. the decision variables) and the dependent variables of the system and, second, propose a techno-economic mathematical method able to determine its minimum installation cost with an integrated approach. Findings: The trade-off between the autoclave installation costs versus the pump installation costs is demonstrated. A sensitive analysis of the cost of the system as function of its decision variables has been performed to propose a practical graphical analysis tools to proper design the integrated pump-autoclave pressured water distribution system. Originality/value: Many previous researches focus only on the pump system optimization or in the tank system optimization without an integrated approach. The wide utilization in industry of the autoclave-pump pressured water distribution system together with the lack of similar contributions in this area enforces the value of this research

Techno-economic design of wind farms: A multi-scenario cost-based application

Wind is a clean source of energy which is spread over wide globe regions. This natural source of energy encourages the planners and stakeholders establishing investments towards installation of wind farms. Wind energy experts are looking through efficient alternatives for the best utilization of the wind energy. Design of wind farms is a fundamental stage of wind energy projects. This study aims to address this issue by considering wind farm design to reduce the levelized cost of the generated wind energy. In the first part of the paper, an analysis of previous research works is carried out to find the latest advancements concerning the design of the wind farm layouts. In the next step, a real application, geo-located in Iran, investigates the effect of different layouts for the wind turbines. A cost approach based on the net present value (NPV) and the levelized cost of energy (LCOE) is used. The results show the optimum positioning of the wind turbines within the site to minimize interferences among the blades maximizing the economic return on the investment

State-of-art review of the optimization methods to design the configuration of hybrid renewable energy systems (HRESs)

The current research aims to present an inclusive review of latest research works performed with the aim of improving the efficiency of the hybrid renewable energy systems (HRESs) by employing diverse ranges of the optimization techniques, which aid the designers to achieve the minimum expected total cost, while satisfying the power demand and the reliability. For this purpose, a detailed analysis of the different classification drivers considering the design factors such as the optimization goals, utilized optimization methods, grid type as well as the investigated technology has been conducted. Initial results have indicated that among all optimization goals, load demand parameters including loss of power supply probability (LPSP) and loss of load probability (LLP), cost, sizing (configuration), energy production, and environmental emissions are the most frequent design variables which have been cited the most. Another result of this paper indicates that almost 70% of the research projects have been dedicated towards the optimization of the off-grid applications of the HRESs. Furthermore, it has been demonstrated that, integration of the PV, wind and battery is the most frequent configuration. In the next stage of the paper, a review concerning the sizing methods is also carried out to outline the most common techniques which are used to configure the components of the HRESs. In this regard, an analysis covering the optimized indicators such as the cost drivers, energy index parameters, load indicators, battery\u2019s state of charge, PV generator area, design parameters such as the LPSP, and the wind power generation to load ratio, is also performed

Techno-economic modelling, analysis and simulation of a water distribution system integrated with pump and autoclave components

Water distribution networks (WDNs), have a complex structure. Their least-cost design and simulation is therefore crucial to convey adequate quantities of water from sources to consumers using the most efficient way. The current research attempts to present an original approach to perform the technical and economic evaluation of a WDN integrated with an autoclave system. For this purpose, a mathematical modelling method is employed to investigate the techno-economic viability of the simulated water system under the effect of the system's design variables. The autoclave's minimum and maximum pressure values as well as the pump flow capacity rates are considered as the free variables of the system and then entered into the proposed analytical model. Afterwards, a tradeoff analysis among the primary components of the system, i.e., pump and autoclave cost has been performed. In the next step, an evaluation on the cost of energy was also carried out to demonstrate the cost variations according to the different pressure values. Results are indicative of the significant changes in the total system cost under the effect of the design variables. In the last stage of this paper, a sensitivity and graphical analysis of the decision variables was also performed to define the input parameters, thus determining the optimum maximum pressure of the autoclave system by which the total cost of the water system is minimized. The technical variables such as the autoclave volume and pump differential head were also investigated during the performed analysis

Theoretical analysis of wind flow characteristics to investigate the mass and momentum parameters using a novel computational fluid dynamics-based approach

In this article, an experimental study of a wind turbine in a wind tunnel is performed. The objective has been to present a novel analytical computational fluid dynamics (CFD)-based approach through considering the residual levels of the mass and momentum parameters under effect of different air flow characteristics surrounding the wind turbine, which have an effect on the power losses, turbine\u2019s performance and the economic viability. The involved decision variables are considered to be the wind velocity, the pressure and the turbulence. Evaluation of the convergence showed that the residual level for the maximum method is estimated to be approximately 10\u20131 to 10\u20133 times higher than the root mean square. Results also concluded that between two studied turbulence models, the turbulence eddy frequency is found to be more efficient compared with turbulence kinetic energy. In higher iterations compared with the initial iterations, a significant difference between the pressure and the Cartesian velocity components has occurred and the residual level of the velocity components indicated a more efficient convergence compared with the pressure. The overall environmental analysis concluded that on the basis of the CFD residual values, it would be possible to adequately determine the CFD efficiency of the wind energy system in a wind tunnel. It has been demonstrated that, among different decision variables, velocity components of the mass and momentum parameters and the turbulence eddy frequency were determined to produce further accurate results in comparison with the pressure and the turbulence kinetic energ