Single Tank System Research Articles

Controlling a Single Tank Liquid Level System with Classical Control Methods and Reinforcement Learning Methods

In this study, the control of the single tank liquid level system used in control systems has been carried out. The control of the single tank liquid level system has been performed with the classic PI, modified PI, state feedback with integrator action, and Q learning algorithm and SARSA algorithms, one of the artificial intelligence methods. The tank system to be modelled was carried out using classical physics, namely Newton's laws. Then, the mathematical model obtained of the system that are continuous model in time is acquired. The originality of the study; the non-linear liquid tank system is controlled by classical controllers and reinforcement methods. For this purpose, the system was firstly designed to model the system, then the system has been linearized at a specific point in order to design classic PI, modified PI, and state feedback with integral. After that, agents of the Q Learning algorithm and SARSA algorithms were trained for the system. Then the agents have controlled the single-level tank system. The results of the classic controllers and supervised controllers are contrasted with regard to performance criteria such as rising time, settling time, overshoot and integral square error. Consequently, Q learning method has produced 0.0804-sec rising time, 0.943 sec settling time and 0.574 integral square errors. So, Q learning algorithm has produced and exhibited more thriving and successful results for controlling single liquid tank system than PI, Modified PI, state feedback controllers and SARSA.

Numerical research on the thermal characteristics and mechanical properties of a molten-salt single tank storage system

Single-tank thermal storage systems are an effective solution for enhancing the stability and continuity of solar power plants. The thermal characteristics and safety of the cycling process are essential indicators of single-tank performance. In this study, an integrated model of the finite volume method (FVM) and finite element method (FEM) is established for a molten-salt single tank system with a composite wall, and the effects of operating parameters and structural parameters on the cyclic dynamic thermal and mechanical characteristics are investigated. Our findings indicate that increasing the inlet flow rate reduces the heat storage capacity and increases thermal efficiency, while increasing the equivalent stress on the tank wall. However, increasing the inlet/outlet temperature difference enhances the thermal efficiency and the wall equivalent stress and reduces the heat storage capacity. Additionally, a reduction in the solid particle diameters improves the dynamic thermal properties of a single tank, and the thermal efficiency increases from 92.1 % to 94.1 % when the particle diameter decreases from 0.05 m to 0.01 m. In a composite wall structure, increasing the firebrick thickness improves the thermal efficiency and mechanical properties of the tank, while increasing the steel shell thickness improves the stress concentration on the tank wall. Therefore, to improve the thermal efficiency of a single tank and guarantee its security, the inlet flow rate and inlet/outlet temperature differences should be controlled within a certain range. Furthermore, the diameters of solid particles should be reduced, the thickness of the firebrick should be increased and the thickness of the steel shell layer should be controlled within a certain range.

Delayed and Partial Mixing Method of Operating Multi-Tank Redox Flow Battery Systems

To reap the benefits of conventional single and multi-tank redox flow battery (RFB) fluid systems, we investigate a delayed and partial mixing methodology for operating RFB tank systems to maximise electrolyte utilisation and storage capacity. The method modulates an optimised mixing timeframe and mixed amounts of momentarily (un)circulated electrolytes in two vertically separated tank sections. The gravity-assisted mixing between the tank sections achieved by siphon or automatic valve ensures continuous uninterrupted flow occurs in a single direction within the cell while lowering additional auxiliary components/energy and system complexity/cost. We applied a detailed Multiphysics simulation of a test vanadium RFB cell to demonstrate the methodology and its capabilities - especially for larger tank volumes. Significant concentration overpotential reduction with the delayed and partial mixing leads to an increment in discharge capacity and energy efficiency up to 6.5% and 2%, respectively, compared to the conventional single tank system. The practical applicability of the investigated system was also discussed as promising for commercial RFB deployments.

Dynamic simulation of a four tank 200 m3 seasonal thermal energy storage system oriented to air conditioning at a dietary supplements factory

The aim of the paper is to simulate multi-tank storage with the thermocline moving from tank to tank and compare the results against single tank storage. No analysis of this nature has previously been performed. The results lend added impetus to developing this new type of thermal energy storage, especially as heat losses through insulation have already been reduced a minimum.Dividing a seasonal thermal energy storage tank into smaller tanks reduces the negative effect of heat transfer through the thermocline. The work is a continuation of the concept already proposed in available literature of using multiple solar energy stores, but we focus mainly on developing a dynamic model of a system of this type and presenting the results of a time and thermocline dependent simulation. The study also encompassed examination of the thickness of thermal insulation of the storage tanks, with definitions of its critical size.Our study revealed that the use of multi-tank thermal energy storage reduces heat loss through the thermocline. This is illustrated mainly by changes in water temperature in the upper part of the tank, which fluctuates across a much smaller range than for a single tank. In the single tank system, the temperature drops below 60 °C, whereas for the multi-tank system it always remains above 64 °C. In addition, in the multi-tank solution the loss caused by the thermocline occurs in only one tank, leaving 3/4 of the storage system unaffected by thermocline loss.

Implementation of PID controller for liquid level system using mGWO and integration of IoT application

Industrial automation is a multi-disciplinary study field that is constantly evolving. This research proposes IoT-based real-time liquid level monitoring and control in a single tank system. A PID controller with parameters sets using a novel modified Grey Wolf Optimization (mGWO) algorithm is used to manage the liquid level. The PID controller was then built on the ESP32 microcontroller module, and an android-based application was created utilizing the Blynk platform for IoT plant monitoring and control. The mGWO algorithm is used in MATLAB to optimize the Kp, Ki, and Kd values of PID controller parameters. The Arduino IDE is used to create the microcontroller programing as well as the interface for the Android application to the ESP32 microcontroller module. The results reveal that a single tank liquid level control system based on mGWO outperforms Ziegler–Nichols and SIMC tuning approaches. Furthermore, the adoption of an IoT application-based user interface boosts the plant’s control and monitoring flexibility.

A Numerical Study for Solving Mathematical Model in Chemistry and Environment

The purpose of this work is to demonstrate how the first order ordinary differential equation may be use as a mathematical model to explain chemical processes and mixture situations. The application of the ordinary differential equation of the first degree was analyze in the modeling of some chemical phenomena, such as clarifying the application in the problems of mixing solutions in both single and multiple tank systems. These problems were develope with the presentation of the first form of the model to include n-tank.

On the Problem of Identification System, Controller Design, Real-Time Fault Detection and Diagnosis for Water Single Tank System

The objective of this paper presents an identification of single water tank system by Genetic Algorithm (GA), a comparison control quality of two controllers sliding mode control (SMC) and fuzzy sliding mode control (FSMC) and a design of real-time fault detection and diagnosis for the system. The entire system has been modeled and tested by Matlab/Simulink toolbox.

Fuel Flowrate Control for Aeroengine and Fuel Thermal Management for Airborne System of Aircraft—An Overview

Fuel flowrate control system and fuel thermal management are very important for aeroengine and the overall aircraft, and it has been researched for several decades. This survey paper makes a comprehensive and systematic overview on the exiting fuel flowrate regulation methods, thermal load of fuel metering units, fuel-based thermal management, and the fuel tank’s thermal management topology network with drain and recirculation. This paper firstly reviews the mechanism, technical advantages, and technical challenges of the fuel metering unit with flowrate control valve and constant pressure difference valve compensator, flowrate control valve and variable displacement pump-based pressure difference compensator, and motor-based flowrate regulation. Then, the technical characteristics of above fuel flowrate control methods related to thermal management are discussed and compared. Meanwhile, the behaviors of recirculated fuel flow within single tank system and dual tank system are explored. Thirdly, the paper discusses the future directions of fuel flowrate control and thermal management. The survey is significant to the fuel flowrate control and fuel thermal management of the aircraft.

Influence of porosity and permeability of flow distributor on thermal stratification in single media storage tank

A single media single tank system is emerging as a promising technology for thermal energy storage. The incorporation of a porous flow distributor in such a system leads to significant improvement of the thermal stratification in the tank. The performance of the flow distributor depends upon the porous structure of the distributor wall. The influence of the distributor on the thermal stratification is well documented; however, the combined effect of porosity and permeability on the thermocline thickness is not yet explored. The objective of the present study is, therefore, to investigate the interdependent effect of the permeability and porosity of the distributor wall on the thermal stratification in the single media single tank storage system. A numerical analysis is performed to evaluate the establishment and progress of thermocline in the storage tank for a wide range of wall-permeability of the vertically mounted flow distributor. The performance of the flow distributor in minimizing the mixing is analyzed through the velocity and temperature fields, stratification number, MIX number, and span of the logistic cumulative distribution function. Results show that the permeability in the range between 10−9 m2 and 10−8 m2, leads to the best thermal stratification and minimum mixing of energy among the given system configurations. Also, the minimal thermocline thickness is achieved to be ∼13% of the entire tank height which is, to the best of our knowledge, considerably lower than the reported value in literature.

Fault compensation effect in fault detection and isolation

<p class="Abstract">This paper discusses the origin and problem of the fault compensation effect. The fault compensation effect is an underrated common side effect of the fault isolation approaches developed within the Fault Detection and Isolation (FDI) community. In part, this is justified due to the relatively low probability of such an effect. On the other hand, there is a common belief that the inability to isolate faults due to this effect is the evident drawback of model-based diagnostics. This paper shows how, and under which conditions, the fault compensation effect can be identified. In this connection, the necessary and sufficient conditions for the fault compensation effect are formulated and exemplified by diagnosing a single buffer tank system in open and closed-loop arrangements. In this regard, we also show the drawbacks of a bi-valued residual evaluation for fault isolation. In contrast, we outline the advantages of a three-valued residual evaluation. This paper also brings a series of conclusions allowing for a better understanding of the fault compensation effect. In addition, we show the difference between fault compensation and fault-masking effects.</p>

The effect of number of tanks on water quality in rainwater harvesting systems under sudden contaminant input

Rainwater harvesting (RWH) is a sustainable solution for curbing existing urban water crises. Many countries have implemented various design guidelines for RWH systems, but water quality issues persist, especially with respect to particulate matter and soluble contaminants entering the RWH system after a prolonged dry period. A first-flush unit in an RWH system can partially manage this sudden influx of pollutants, provided that rainfall conditions are favorable for its optimal operation. Therefore, a significant proportion of these pollutants reach the storage tank. The most common single storage tank RWH systems accumulate particulate matter, and allow soluble and particulate contaminants to reach the outlet quickly at undesirably high concentrations. To overcome these issues pertaining to single tank systems, multiple tank systems with similar volumes have been implemented globally. However, limited research has been conducted to assess the effect of the number of tanks on harvested water quality under a sudden pollutant input. Hence, the authors have investigated the effect of the number of tanks on particulate matter distribution in multi-tank systems, and observed that more than 60% of the particle mass input was retained in the first tank. By increasing the number of tanks, the particle mass reaching the final tank becomes constant despite changes in the flowrate and influx particle mass. Furthermore, a soluble contaminant entering a multi-tank system was observed to reside within the system for a prolonged time by approximately a factor of two, which is favorable for developing a response strategy. It is recommended by the authors that at least three tanks should be used to gain the benefits of a multiple-tank RWH system.

Thermocline control through multi-tank thermal-energy storage systems

Thermal-energy storage systems consisting of multiple tanks allow the implementation of thermocline-control methods, which can reduce the drop in the outflow temperature during discharging and increase the volumetric storage density and utilization factor. Multi-tank systems based on the extraction and mixing thermocline-control methods were assessed using simulations assuming fluvial rocks as storage material and compressed air as heat-transfer fluid. For adiabatic conditions, the simulations showed improved performance for all multi-tank systems, with diminishing improvements as the number of tanks increases. The mixing method performed better than the extraction method. The mixing method delivered an outflow temperature drop of 5.1% using two tanks whose total volume was 2.15 times smaller than that of the single-tank system. For diabatic conditions, more than three tanks were not beneficial. With two tanks, the mixing method attained a temperature drop of 5.8% with a volume that is 2.5 times smaller than that of the single-tank system. The exergy efficiency of the two-tank system was 91.3% compared to 98.1% of the single-tank system. The specific material costs of the two-tank system were 1.5 times lower than those of the single-tank system.

Evidence of total suspended solids control by Mugil liza reared in an integrated system with pacific white shrimp Litopenaeus vannamei using biofloc technology

The biofloc culture system (BFT) allows for the production of aquatic animals at higher stocking densities compared to conventional aquaculture systems and it has been proven to be efficient for shrimp (Litopenaeus vannamei) and mullet (Mugil liza) rearing. Accumulation of nutrients enhances the natural productivity of the system, thus the concentration of total suspended solids (TSS) tends to accumulate during the production cycle, which can deteriorate the water quality and performance of the animals produced. Integrated multi trophic aquaculture (IMTA) can be performed in single or multi tank systems, depending on the interaction of the different species being cultured. The present study aimed to reduce TSS concentration by integrating juvenile mullet into a shrimp BFT system, through the consumption of these solids by the mullet. Three different treatments were used: shrimp monoculture (MONO), single tank (SING -shrimp and mullet cultured in the same tank) and IMTA multi tank (MULT- shrimp and mullet cultured in different tanks). The performance of shrimp was impaired in the SING treatment, while mullet had their best zootechnical performance in this treatment. The presence of the fish modified the nitrification even with the use of biofloc inoculum. The presence of mullet, regardless of the IMTA system used, resulted in lower biofloc concentrations, compared to the monoculture of shrimp, thus confirming that mullet can be used to control solids concentrations originating from shrimp production in a BFT system.

Regulation of the output temperature in a novel water heating system using solid graphite as sensible heat thermal energy storage medium: Effects of water tank

The quality of output temperature is one of the key parameters for the reliability of water heating system. In this work a simulation work was done to regulate the output temperature in a novel water heating system using solid graphite as thermal energy storage medium. The effects of water tank on the quality of output temperature was considered. Two different strategies were thus considered: (i) single tank system, and (ii) double-tank system. And two different working conditions were analyzed: (i) standard design condition, and (ii) demand change conditions. The results showed that the application of water tanks can reduce the standard deviation of output temperature by 68.49% and 68.81% under the standard design condition, respectively. And the improvement is highly related to the capacity of hot water tank. For the demand change condition, the regulation strategy was carried out based on the criterion of heat power equilibrium. The results showed that the single tank system will deteriorate the reliability of water heating for demand change condition, though it can reduce the oscillation of the output temperature. For the double-tank system, a two-step adjustment method was applied. The results showed that the average output temperature can be quite close to the target value when demand ratio changes to 0.8 and 0.9. And the standard deviation of temperature has also reduced by 24.19% and 63.06%, respectively.

Computational prediction of significant efficiency gain through multi-tank modular heat storage for solar thermal systems with variable-temperature input profile

Storage is essential for making the solar thermal technologies stand-alone. For the time scale of a day for few days, sensible heat storage with low thermal inertia is a reasonable choice which has the advantage of fast kinetics and lower cost compared to the latent heat or thermochemical routes. In an earlier study, it has been demonstrated experimentally that the sensible heat storage can be made more efficient by modularization. However, the real potential of modular heat storage is experienced with high temperature heat with significant temperature variations. Here, we simulate such heat storage processes for realistic solar thermal heat profile and compare the performance of multi-tank modular system with that of conventional single tank system. We find that the roundtrip storage efficiency can be improved by more than double in terms of enthalpy and more than quintuple in terms of exergy for the given heat profiles. Although the exact quantitative enhancement depends on the temperature variability of the input, the methodology of such analysis and design as employed in this study is universally applicable. It is observed that the improvement in terms of exergy is significantly higher than that in terms of enthalpy. Therefore, the real benefit of such modular heat storage systems will be seen in case of high temperature solar power cycles, particularly based on the solar tower technology.

Non-Linear Tank Level Control for Industrial Applications

Tank level control is ubiquitous in industry. The focus of this paper is on accurate liquid level control in single tank systems which can be actuated continuously and modulation of the level setpoint is also required, for example in cascade control loops or supervisory Model Predictive Control (MPC) applications. To avoid common problems encountered when using fixed gain or adaptive/gain scheduled schemes, an accurate technique based around feedback linearization and Proportional Integral (PI) control is introduced. This simple controller can maintain linear performance over the full operating range of a uniform tank. As will be demonstrated, the implementation overhead compared to a regular PI controller is negligible, making it ideal for industrial implementation. Implementation details and parameter identification for adaptive implementation are discussed. Simulations coupled with experimental results using a large-scale laboratory level control system using commercial industrial control equipment validate the approach, and illustrate its effectiveness for both level tracking and disturbance rejection.

Improvement of the efficiency of solar thermal energy storage systems by cascading a PCM unit with a water tank

Abstract For solar heating systems, adding phase change material (PCM) can significantly increase the thermal storage capacity. This paper proposes a system using a PCM thermal storage unit cascadely combined with a water tank and configures a composite PCM suitable for the system. This study investigates the impact of this system configuration on the system efficiency while developing a matching principle between components. The system model is built using TRNSYS software; considering the supercooling property, a numerical calculation program of the PCM unit is compiled and verified. The optimal parameters of the PCM are studied by simulations. Finally, sodium acetate trihydrate mixtures are configured and selected as the PCM. The results show that the phase change temperature range suitable for conventional heating systems is 47.5–57.5 °C. The combined use of the PCM unit and water tank can increase the efficiency of the heat storage system. The optimal volume ratio of the PCM unit is 0.67–0.78. Compared with a single water tank system, the solar fraction of the series system can be increased by approximately 30%. Compared with a water tank-PCM unit parallel system, the PCM in the series system effectively increases the system heat collection and enhances the solar fraction by 5%–12%.

Modelling of Level Process

Industries such as, textile, food processing, chemical and water treatment plants are part of our global development. The efficiency of processes used by them is always a matter of great importance. Efficiency can be greatly improved by obtaining an exact model of the process. This paper studies the two main classifications of model development – First-Principles Model and Empirical Model. First-Principles Model can be obtained with an understanding of the basic physics of the system. On the other hand, Empirical Models require only the input-output data and can thus factor in process non-linearity, disturbances and unexpected errors.This paper utilizes the System Identification Toolbox in MATLAB for empirical model development. Models are developed for a single tank system, a classic SISO problem and for the two interacting tank system. Both systems are studied with respect to three operating points, each from a local linear region. The obtained models are validated with the real-time setup. They are satisfactory in their closeness to the real time process and hence deemed fit for use in control algorithms and other process manipulations.

Optimal tuning of FOPID controller based on PSO algorithm with reference model for a single conical tank system

The fractional order proportional integral derivative controller (FOPID) replaces the conventional PID controller for its immense merits such as its simple structure, better set point tracking, high disturbance rejection, higher capability of handling model uncertainties in nonlinear and real time applications. This paper addresses the effectiveness of the FOPID controller on a level control of single conical system in real time. It is one of the classical nonlinear control problem and its shape not only contributes the proper mixing of liquids and also guarantee to drainage of solid wastes. This study, a dual loop controller is proposed and constructed with a master process and slave process for a level control of a single conical tank system. In the slave process, the output response obtained by the traditional PID controller combined with the conical tank reference model and compared with the output response of the master process. The obtained error signal is used to dynamically correct the parameters of the FOPID controller in the master process. The tuning of FOPID controller is a challenging task due to its presence of extra parameters and it efficiently carried out by particle swarm optimization (PSO) algorithm. The obtained result reveals that the Proposed PSO optimized FOPID controller with reference model demonstrated the better set point tracking, smooth controller response than other conventional integer order controllers.

Comparative experimental study on parabolic trough collector integrated with thermal energy storage system by using different reflective materials

The present study focuses on the performance analysis of parabolic trough collector (PTC) incorporated with single-tank thermal energy storage (TES) system with the use of two different reflective materials in PTC which includes glass and high-reflective stainless steel sheet. It consists of TES tank which contains 110 L of Therminol-66 oil (heat transfer fluid). The experiments are conducted for the use of glass reflective material PTC and stainless steel reflective material PTC when both are integrated with TES system. The various performance parameters like useful energy gained by the PTC, energy collected in the PTC, PTC efficiency, heat loss coefficient and the stored amount of energy in TES tank are calculated to know the overall efficiency of the system during daytime. It has been concluded that the use of glass as the reflective material in PTC has better useful heat gain and high average PTC efficiency in comparison with stainless steel reflective material. However, the overall system performance is almost equal to both reflective materials. Silver-coated stainless steel reflective material may be preferred in PTC when it is coupled with single TES tank system, due to cost effectiveness and ease availability with a high-reflective power about 98.9%.