Concentrated solar power plants (CSPs) are gaining increasing interest, mostly as parabolic trough collectors (PTC) or solar tower collectors (STC). Notwithstanding CSP benefits, the daily and ...monthly variation of the solar irradiation flux is a main drawback. Despite the approximate match between hours of the day where solar radiation and energy demand peak, CSPs experience short term variations on cloudy days and cannot provide energy during night hours unless incorporating thermal energy storage (TES) and/or backup systems (BS) to operate continuously. To determine the optimum design and operation of the CSP throughout the year, whilst defining the required TES and/or BS, an accurate estimation of the daily solar irradiation is needed. Local solar irradiation data are mostly only available as monthly averages, and a predictive conversion into hourly data and direct irradiation is needed to provide a more accurate input into the CSP design. The paper (i) briefly reviews CSP technologies and STC advantages; (ii) presents a methodology to predict hourly beam (direct) irradiation from available monthly averages, based upon combined previous literature findings and available meteorological data; (iii) illustrates predictions for different selected STC locations; and finally (iv) describes the use of the predictions in simulating the required plant configuration of an optimum STC.
The methodology and results demonstrate the potential of CSPs in general, whilst also defining the design background of STC plants.
The Third Modeling Workshop focusing on bioprocess modeling was held in Kenilworth, NJ in May 2019. A summary of these Workshop proceedings is captured in this manuscript. Modeling is an active area ...of research within the biotechnology community, and there is a critical need to assess the current state and opportunities for continued investment to realize the full potential of models, including resource and time savings. Beyond individual presentations and topics of novel interest, a substantial portion of the Workshop was devoted toward group discussions of current states and future directions in modeling fields. All scales of modeling, from biophysical models at the molecular level and up through large scale facility and plant modeling, were considered in these discussions and are summarized in the manuscript. Model life cycle management from model development to implementation and sustainment are also considered for different stages of clinical development and commercial production. The manuscript provides a comprehensive overview of bioprocess modeling while suggesting an ideal future state with standardized approaches aligned across the industry.
This review covers multiple types and scales of modeling used in the bioprocessing industry from biophysical models at the molecular level and up through large scale facility and plant modeling. The current state of bioprocess modeling is assessed, and an idealized future state is proposed.
Abstract
Simulation is an important technical means to verify the efficiency of discrete event systems. This paper summarizes the research system of plant simulation software based on discrete event ...system, including production layout, routing, material distribution, production line and other aspects. Finally, in view of the shortcomings of plant simulation in simulation, the future improvement and research direction are pointed out.
Scalability is a key feature of reconfigurable manufacturing systems (RMS). It enables
fast and cost-effective adaptation of their structure to sudden changes in product demand.
In principle, it ...allows to adjust a system's production capacity to match the existing orders. However, scalability can also act as a "safety buffer" to ensure a required minimum
level of productivity, even when there is a decline in the reliability of the machines that
are part of the machine tool subsystem of a manufacturing system. In this article, we
analysed selected functional structures of an RMS under design to see whether they
could be expanded should the reliability of machine tools decrease making it impossible to achieve a defined level of productivity. We also investigated the impact of the
expansion of the system on its reliability. To identify bottlenecks in the manufacturing
process, we ran computer simulations in which the course of the manufacturing process
was modelled and simulated for 2-, 3-, 4- and 5-stage RMS structures using Tecnomatix
Plant Simulation software.
As traditional sources of energy recede and demand for energy rises at an unprecedented pace, it is difficult for the available sources to satisfy demands. As a result, this research focuses on ...combining conventional generation with distributed generation, each of which can be used independently. For both industrial and residential electricity suppliers, providing a secure, continuous, and safe electrical supply is a critical necessity. As we progress toward a more sustainable approach to generating electricity (both renewable and nuclear) from the currently prevalent non-renewable sources, a hybrid supply system is an intermediate phase. This project aims to simulate a three-phase power plant that incorporates a conventional steam turbine and a DC-AC inverter generation device powered by solar to produce a total of 100kW of power with a power factor of 1. The input torque to the synchronous generator and the DC voltage to the distributed system vary depending on the output power potential of each system. Both devices achieve a constant voltage at the load. When the two systems work independently, the voltages produced by both are in phase and have the same amplitude.
An optimization of the production process is defined as the search for solutions with improved production efficiency. Process optimization should be one of the main components of a business strategy ...that not only delivers benefits to customers but also helps increase the performance of production processes and benefits the entire business. The traditional approaches to job shop scheduling are based on the exact mathematically formalized model. If the number of model parameters is high and the environment is rather uncertain, the practical applications are quite restricted. That is why the theory proposes an approach based on a large-scale computer simulation. The main goal of this paper is to show that in a concrete company case, the simulation-based approach provides increased productivity. The presented study proposes the practical application of the Tecnomatix software used in the research to optimize the production system. The partial aims of the paper are as follows: (1) to create a simulation model of the production system with the help of the Plant Simulation module, (2) to model the current state of matters in the company, and (3) to propose a solution to the problem. Ultimately, we show that the simulation approach to the production line control provides rather effective solutions when compared to the intuitive one based on trial-and-error experience. The improvement includes a significant (1) shortening of the production cycle and (2) increase in productivity.
► Conventional solar plants achieves an overall efficiency of 15.3%. ► Solar salts increases efficiency with crystallization issues as drawback. ► Innovative lay-outs were investigated aiming at ...higher efficiency and lower costs. ► Innovative lay-out increases efficiency by 16% compared to reference cases.
Solar thermal plants are among the most promising technologies to replace fossil fuel stationary applications, and within solar thermal technologies, parabolic troughs are considered the most mature application in the market. This paper compares different solar field technologies, in terms of both performance at design conditions and annual energy production; an in-house code, PATTO, was used to perform energy balances. We considered a reference case reflecting state-of-the-art Nevada Solar One, which showed a design efficiency and annual average efficiency of 22.4% and 15.3%, respectively, in agreement with actual performance. If solar salts are used as heat-transfer fluid instead of synthetic oil (e.g. ARCHIMEDE plant), the efficiency improved within the range of 6% due to the higher maximum temperature. Further thermodynamic advantages can be achieved with a direct steam generation plant; the main drawback is the more complex transient control and no commercially available storage systems. We propose the innovative Milan configuration, which combines advantages of direct steam evaporation and the use of a heat-transfer fluid, to investigate both synthetic oil and solar salts for steam superheating and reheating. Results for this configuration are very promising, with a sun-to-electric annual average efficiency of 17.8%, which is 16% higher than the reference case. Detailed daily simulations showed that advantages are more significant at low radiation. However, the plant should be optimized on an economic basis and we will discuss this in a future paper.
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