scholarly journals Modelling and control of solar-driven humidification–dehumidification desalination plant

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Bahy Gabra ◽  
Mohamed Rady ◽  
A. M. Abdel Ghany ◽  
Mohamed. A. Shamseldin
Keyword(s):  
Plant Performance ◽  
Pid Controllers ◽  
Outlet Temperature ◽  
Desalination Plant ◽  
Environment Model ◽  
Pump Flow Rate ◽  
Static Performance ◽  
Weather Changes ◽  
And Control ◽  
Solar Field

AbstractThis article reports on mathematical modelling and control of a solar-driven humidification–dehumidification desalination plant. Mathematical models for the components are constructed using CARNOT toolbox in MATLAB environment. Model validation has been shown by comparison with published experimental data. Solar collector outlet temperature control is a key parameter to optimize plant performance. In this study, solar field pump flow rate is controlled to maintain the collector outlet temperature at a predetermined set value. Three types of PID controllers are tested. These include PID, nonlinear PID and fractional-order PID. Controllers’ gains are optimized using genetic algorithm technique. The results show that FOPID controller offers a superior dynamic and static performance and can be automatically adjusted to compensate for weather changes.

Development of a Jacobian Module for Advanced Pulp and Paper Simulation and Control

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 4-11
Author(s):  
MOHAMED CHBEL ◽  
LUC LAPERRIÈRE
Keyword(s):  
Control System ◽  
Nonlinear Behavior ◽  
Simulation Software ◽  
Pulp And Paper ◽  
Pid Controllers ◽  
Tuning Parameters ◽  
Pid Tuning ◽  
Fixed Set ◽  
And Control ◽  
Operating Points

Pulp and paper processes frequently present nonlinear behavior, which means that process dynam-ics change with the operating points. These nonlinearities can challenge process control. PID controllers are the most popular controllers because they are simple and robust. However, a fixed set of PID tuning parameters is gen-erally not sufficient to optimize control of the process. Problems related to nonlinearities such as sluggish or oscilla-tory response can arise in different operating regions. Gain scheduling is a potential solution. In processes with mul-tiple control objectives, the control strategy must further evaluate loop interactions to decide on the pairing of manipulated and controlled variables that minimize the effect of such interactions and hence, optimize controller’s performance and stability. Using the CADSIM Plus™ commercial simulation software, we developed a Jacobian sim-ulation module that enables automatic bumps on the manipulated variables to calculate process gains at different operating points. These gains can be used in controller tuning. The module also enables the control system designer to evaluate loop interactions in a multivariable control system by calculating the Relative Gain Array (RGA) matrix, of which the Jacobian is an essential part.

scholarly journals Solar Field Output Temperature Optimization Using a MILP Algorithm and a 0D Model in the Case of a Hybrid Concentrated Solar Thermal Power Plant for SHIP Applications

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3731
Author(s):  
Simon Kamerling ◽  
Valéry Vuillerme ◽  
Sylvain Rodat
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Solar Thermal ◽  
Outlet Temperature ◽  
Field Mass ◽  
Heat Demand ◽  
Process Heat ◽  
Solar Field ◽  
Control Trajectory

Using solar power for industrial process heat is an increasing trend to fight against climate change thanks to renewable heat. Process heat demand and solar flux can both present intermittency issues in industrial systems, therefore solar systems with storage introduce a degree of freedom on which optimization, on a mathematical basis, can be performed. As the efficiency of solar thermal receivers varies as a function of temperature and solar flux, it seems natural to consider an optimization on the operating temperature of the solar field. In this paper, a Mixed Integer Linear Programming (MILP) algorithm is developed to optimize the operating temperature in a system consisting of a concentrated solar thermal field with storage, hybridized with a boiler. The MILP algorithm optimizes the control trajectory on a time horizon of 48 h in order to minimize boiler use. Objective function corresponds to the boiler use, for completion of the heat from the solar field, whereas the linear constraints are a simplified representation of the system. The solar field mass flow rate is the optimization variable which is directly linked to the outlet temperature of the solar field. The control trajectory consists of the solar field mass flow rate and outlet temperature, along with the auxiliary mass flow rate going directly to the boiler. The control trajectory is then injected in a 0D model of the plant which performs more detailed calculations. For the purpose of the study, a Linear Fresnel system is investigated, with generic heat demand curves and constant temperature demand. The value of the developed algorithm is compared with two other control approaches: one operating at the nominal solar field output temperature, and the other one operating at the actual demand mass flow rate. Finally, a case study and a sensitivity analysis are presented. The MILP’s control shows to be more performant, up to a relative increase of the annual solar fraction of 4% at 350 °C process temperature. Novelty of this work resides in the MILP optimization of temperature levels presenting high non-linearities, applied to a solar thermal system with storage for process heat applications.

Effect of blood viscosity on the performance of virtually wall-less venous cannulas

Perfusion ◽  
2019 ◽  
Vol 35 (5) ◽  
pp. 393-396
Author(s):  
Saad Abdel-Sayed ◽  
Philippe Abdel-Sayed ◽  
Denis Berdaj ◽  
Enrico Ferrari ◽  
Maximilian Halbe ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Target Volume ◽  
Inlet Pressure ◽  
Thin Wall ◽  
Test Medium ◽  
Lower Reservoir ◽  
Pump Flow Rate ◽  
Pump Inlet ◽  
And Control

Aim: This study was designed to quantify the influence of blood as test medium compared to water in cannula bench performance assessment. Methods: An in vitro circuit was set-up with silicone tubing between two reservoirs. The test medium was pumped from the lower reservoir by centrifugal pump to the upper reservoir. The test-cannula was inserted in a silicone tube connected between the lower reservoir and the centrifugal pump. Flow rate and pump inlet-pressure were measured for wall-less versus thin-wall cannula using a centrifugal pump in a dynamic bench-test for an afterload of 40-60 mmHg using two media: blood 10 g/dL and 5.6 g/dL and water 0 g/dL. Results: The wall-less cannula showed significantly higher flows rates as compared to the thin-wall cannula (control), with both hemoglobin concentrations and water. Indeed, for a target volume of 200-250 mL of blood (Hg 10 g/dL) in the upper reservoir, the cannula outlet pressure (P) was −14 ± 14 mmHg versus −18 ± 11 mmHg for the wall-less and control respectively; the cannula outlet flow rate (Q) was 3.91 ± 0.41 versus 3.67 ± 0.45 L/min, respectively. At the same target volume but with a Hg of 5.7 g/dL, P was −16 ± 12 mmHg versus −19 ± 12 mmHg and Q was 4 ± 0.1 versus 4 ± 0.4 L/min for the wall-less cannula and control respectively. Likewise, P and Q values with water were −1 mmHg versus −0.67 ± 0.58 mmHg and 4.17 ± 0.45 L/min versus 4.08 ± 0.47 L/min for the wall-less and control respectively. Conclusion: Walls-less cannula showed 5.6% less pump inlet-pressure differences calculated between blood and water, as compared to that of thin-wall cannula (−21 times). Flow differences were 6% and 10% for the walls-less and thin-wall cannula respectively. We conclude that testing the cannula performance with water is a good scenario and can overestimate the flow by a 10%. However, superiority for wall-less is preserved with both water and blood.

Innovative Computing Techniques for Development of an Integrated Computer Control System

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1365-1374 ◽  
Author(s):  
G. G. Patry ◽  
M. W. Barnett
Keyword(s):  
Wastewater Treatment ◽  
Object Oriented Programming ◽  
Plant Performance ◽  
Organic Load ◽  
Model Parameters ◽  
Process Data ◽  
Wastewater Treatment Process ◽  
Deterministic Modelling ◽  
Linear Differential ◽  
And Control

Over the past decade there has been a shift in emphasis from design and construction of wastewater treatment facilities to operation. Poor plant performance, high costs and damage to the environment have resulted from operational problems. Wastewater treatment consists of a complex sequence of inter-dependent biological, physical and chemical processes subject to time-varying hydraulic and organic load conditions. Wastewater treatment process operation and control is a knowledge intensive task. Research on improving operation and control has centred on identifying important mechanisms responsible for observed behaviour and modelling both the process and optimum ways of operating the process. These models have served as useful tools for improving operation and control. Many different approaches have been used, including deterministic modelling, stochastic modelling and, more recently, linguistic modelling. Complex mathematical models of wastewater treatment processes consisting of large numbers of non-linear differential equations can be constructed using tools such as the General Purpose Simulator (GPS) and, given appropriate data, model parameters can be evaluated and updated using existing optimization routines. Object oriented programming (OOP) and a model based reasoning (MBR) approach provides a useful framework for development of deep-knowledge expert systems (ES). Data-driven modelling methods, including both time series analysis and artificial neural network (ANN) techniques, can also be employed to make maximum use of information contained in process data. Each of these model types is a necessary component of a computer system for operational control of wastewater treatment but, in isolation, none are sufficient for making the system robust. An integrated environment for combining these techniques has been developed for this purpose and the basis for its development is described.

PerformanceAnalysis of Integrated Solar Combined Cycle Power Plant for Dhahran, Saudi Arabia

2014 ◽  
Vol 492 ◽  
pp. 568-573 ◽  
Author(s):  
Yinka Sofihullahi Sanusi ◽  
Palanichamy Gandhidasan ◽  
Esmail M.A. Mokheimer
Keyword(s):  
Saudi Arabia ◽  
Gas Turbine ◽  
Combined Cycle ◽  
Plant Performance ◽  
Steam Turbines ◽  
Steam Generation ◽  
Power Requirement ◽  
Gas Turbine Exhaust ◽  
Auxiliary Heater ◽  
Solar Field

Saudi Arabia is blessed with abundant solar energywhichcan be use to meet its ever increasing power requirement. In this regard, the energy analysis and plant performance of integrated solar combined cycle (ISCC) plant with direct steam generation (DSG) was carried out for Dhahran, Saudi Arabia using four representative months of March, June, September and December. The plant consists of 180MW conventional gas turbine plant and two steam turbines of 80MW and 60MW powered by the solar field and gas turbine exhaust. With high insolation during the summer month of June the plant can achieve up to 25% of solar fraction with ISCC plant efficiency of 45% as compared to gas turbine base of 38%.This can however be improved by increasing the number of collectors or/and the use of auxiliary heater .

The Impact of Hybrid Wet/Dry Cooling on Concentrating Solar Power Plant Performance

2010 ◽  
Author(s):  
Michael J. Wagner ◽  
Charles Kutscher
Keyword(s):  
Solar Power ◽  
Rankine Cycle ◽  
Plant Performance ◽  
Concentrating Solar Power ◽  
Heat Rejection ◽  
Power Block ◽  
Lower Temperature ◽  
Solar Field ◽  
The Impact ◽  
Dry Cooling

This paper examines the sensitivity of Rankine cycle plant performance to dry cooling and hybrid (parallel) wet/dry cooling combinations with the traditional wet-cooled model as a baseline. Plants with a lower temperature thermal resource are more sensitive to fluctuations in cooling conditions, and so the lower temperature parabolic trough plant is analyzed to assess the maximum impact of alternative cooling configurations. While low water-use heat rejection designs are applicable to any technology that utilizes a Rankine steam cycle for power generation, they are of special interest to concentrating solar power (CSP) technologies that are located in arid regions with limited water availability. System performance is evaluated using hourly simulations over the course of a year at Daggett, CA. The scope of the analysis in this paper is limited to the power block and the heat rejection system, excluding the solar field and thermal storage. As such, water used in mirror washing, maintenance, etc., is not included. Thermal energy produced by the solar field is modeled using NREL’s Solar Advisor Model (SAM).

Dynamic Model Development of Linear Fresnel Solar Field

2015 ◽  
Author(s):  
Elina Hakkarainen ◽  
Matti Tähtinen ◽  
Hannu Mikkonen
Keyword(s):  
Control System ◽  
Dynamic Simulation ◽  
Model Development ◽  
Control Mode ◽  
Plant Behavior ◽  
Clear Sky ◽  
Control Scheme ◽  
Control Schemes ◽  
And Control ◽  
Solar Field

As a dispatchable clean energy source, concentrated solar power (CSP) can be one of the key technologies to overcome many problems related to fossil fuel consumption and electricity balancing problems. Solar is a variable location, time and weather dependent source of energy, which sets challenges to solar field operations. With proper dynamic simulation tools it is possible to study dynamics of CSP field under changing weather conditions, find optimum control strategies, and plan and predict the performance of the field. CSP technology considered in this paper, linear Fresnel reflector (LFR), is a proven line focusing technology, having simpler design but suffering in optical performance compared to more mature parabolic trough (PT) technology. Apros dynamic simulation software is used to configure and simulate the solar field. Apros offers a possibility to dynamically simulate field behavior with varying collector configuration, field layout and control mode under varying irradiation conditions. The solar field applies recirculation (RC) as a control mode and direct steam generation (DSG) producing superheated steam. DSG sets challenges for the control scheme, which main objective is to maintain constant steam pressure and temperature at the solar field outlet under varying inlet water and energy conditions, while the steam mass flow can vary. The design and formulation of an entire linear Fresnel solar field in Apros is presented, as well as the obtained control scheme. The field includes user defined amount of collector modules, control system and two modules describing solar irradiation on the field. As two-phase water/steam flow is used, an accurate 6-equation model is used in Apros. Irradiation on the solar field under clear sky conditions is calculated according to time, position and Linke turbidity factor. Overcast conditions can be created by the clear sky index. For LFR single-axis sun tracking system is applied. In order to test the model functionality and to investigate the field behavior, thermal performance of the field was simulated at different dates at two different locations, and the results were compared. Similar field dimensions and control schemes were applied in each case, and simulations were done for full 24 hours in order to study the daily operations and ensure process stability. Control scheme functionality is evaluated based on the plant behavior in simulation cases having different operational conditions. The proper operability of the configured LFR model is evaluated. Obtained performance results show differences between locations and variation depending on season and time. The importance of a proper control system is revealed. The results show that the dynamic model development of a solar field is necessary in order to simulate plant behavior under varying irradiation conditions and to further develop optimal field control schemes and field optimizing process. The future work in the development of the LFR model presented will focus on dynamic response behavior development under transient conditions and field start-up and shut down procedure development.

On the Control of the Collector Field Outlet Temperature of Shiraz 250 KW Solar Power Plant

2012 ◽  
Vol 260-261 ◽  
pp. 163-168 ◽  
Author(s):  
Mostafa Zamani Mohi Abadi ◽  
Seyed Mohammad Hessam Mohammadi ◽  
Seyed Ali Akbar Safavi ◽  
Seyed Vahid Naghavi
Keyword(s):  
Power Plant ◽  
Solar Power ◽  
Real Data ◽  
Outlet Temperature ◽  
Solar Power Plant ◽  
Modeling And Control ◽  
The Real ◽  
Standard Tool ◽  
And Control ◽  
Control Study

This paper presents a control study of the real Shiraz 250KW solar power plant together with a modeling and a monitoring interface. Here, a PID controller is developed to control the outlet oil temperature of the collector field of the solar power plant as a standard tool for industrial automation. First the power plant is modeled within MATLAB environment and the model is verified with the real data of the power plant. Then an HMI environment is developed within the LabVIEWsoftwarewhile incorporating the model developed in MATLAB. The simulation results showed that a fixed-coefficient PID failed to provide the desired results over a year and the best coefficients for each month were calculated. The friendly and accurate developed environment within MATLAB and LabVIEW provide a valuable tool for modeling and control studies and monitoring of the real power plant.

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