Application Of Temperature Control Research Articles

Review of Neural Network Algorithm and its Application in Temperature Control of Distillation Tower

Distillation process is a complex process of conduction, mass transfer and heat conduction, which is mainly manifested as follows: The mechanism is complex and changeable with uncertainty; the process is multivariate and strong coupling; the system is nonlinear, hysteresis and time-varying. Therefore, traditional control methods are difficult to accurately control, but neural networks can greatly improve this problem. This article introduces the basic concepts of distillation tower temperature control, comprehensively introduces the application of various neural network algorithms in distillation tower temperature control, and compares their advantages and disadvantages and their effect. At present, there are many researches on neural network control of distillation tower temperature. The methods are different and each has its own merits. This article has carried out a systematic review to provide reference for the development of related industries.

Lifetime improvement for wind power generation system based on optimal effectiveness of thermal management

The power module plays a vital role in the renewable energy conversion. But it is one of the most prone to fail components in the wind energy system. The thermal management has been proved to be a cost-effective mean to improve the reliability of wind energy system, but it has a dual nature. To balance the benefit and risk of thermal management, a lifetime extension strategy is proposed. This strategy considers the minimum junction temperature fixed to the lowest ambient temperature and the allowed maximum junction temperature determined by the predefined temperature swing. Then the related wind speeds of predefined temperature swing can be concentrated in a part wind speed area and the effectiveness of thermal management under each predefined temperature swing is calculated. The optimal effectiveness is chosen as a quantitative evaluation criterion to design the working range of thermal management and control target of junction temperature in a long time scale. As a benefit, the economic performance of thermal management is greatly improved in that each application of temperature control can reduce as much consumed lifetime of power module as possible. Case studies and experiments are presented for performance verification of proposed strategy. Results show that the consumed lifetime reduced by each application of temperature control is 6.04 × 10-3%. The expected lifetime of power module is extended from 7.55 years to 22.08 years which meets the target lifetime of wind power generation system (20 years). In addition, this method only needs to be applied in the specified working range where the wind speed is higher than 9.30 m/s. Thus, the disturbance on the system's normal operation is significantly alleviated.

Proposal and parametric study of solar absorption/dual compression hybrid refrigeration system for temperature and humidity independent control application

The solar absorption refrigeration technology plays a major role in the building energy saving and emission reduction. According to the concept of energy cascade utilization, this paper proposes a novel solar absorption/dual compression hybrid refrigeration (SADC-HR) system, which consists of solar-driven single effect absorption refrigeration (SSAR) subsystem and power-driven dual-source dual-compression refrigeration (PDCR) subsystem. An air-cooled compression refrigeration (ACR) cycle is integrated with the water-cooled compression refrigeration (WCR) cycle to make up the PDCR subsystem, so as to satisfy the all-weather space cooling/heating demand. The SADC-HR system achieves the cascade production and utilization of cold energy for the temperature and humidity independent control air conditioning system. The thermodynamic model of the SADC-HR system is built to evaluate the system performance and operating parameters, and the comparisons with two conventional systems are also discussed. The results indicate that there are optimum generating temperature of 70 °C and optimum evaporating temperature of 18 °C for the SSAR subsystem to obtain the lowest power consumption at low solar intensity of 450 W/m2. The SADC-HR system also exhibits better economic performance, and its solar collector area is respectively 55.79% and 34.75% lower than that of the conventional SSAR system and solar absorption-compression cascade refrigeration (SA-CCR) system at low solar intensity of 450 W/m2. In addition, the proposed system shows the better energy-saving performance as well as a smaller environmental impact, whose power consumption is reduced by 61.47% compared with the conventional SA-CCR system at solar intensity of 800 W/m2, and the present case study demonstrates that total seasonal electricity consumption in the SADC-HR system decreases a value of 25.32% which corresponds to a decline of 21580.66 kg of CO2 emission in comparison with the conventional ACR system.

Model-based fuzzy control results for networked control systems

This paper discusses aspects concerning the design of model-based fuzzy controllers for Networked Control Systems (NCSs). The stability analysis is related to the characteristic equation of these control systems, where the variable time delays create numerical problems. These numerical problems are first briefly investigated, along with signal processing aspects concerning NCSs. The popular Hilbert-Huang transform is applied to smooth the signals and also the variable time delay, also called latency, due to the communication in the network. The design of Takagi-Sugeno-Kang Proportional-Integral-fuzzy controllers dedicated to temperature control applications is next carried out; the stability of fuzzy NCSs is guaranteed by computing the controller tuning parameters as solutions to linear matrix inequalities. Experimental results for a laboratory equipment that models a first-order plus time delay process are included to validate the theoretical findings.

Daytime radiative cooling purposes with selective multilayer design based on Ta2O5

Nighttime radiative cooling is the natural phenomenon by which the radiators lose heat via thermal radiation using the transparency window (8–13) μm. Historically, nighttime radiative cooling purposes have been investigated for a long time, but daytime radiative cooling has not been yet extensively studied. The daytime cooling operation requires a cover shield, which not only provides extremely high mid-infrared emissivity, but also rejects solar radiation. In this paper, we study numerically a multilayer structure that has both high emissivity in atmospheric window and high reflectivity in the visible and near infrared spectrums, which are difficult to achieve simultaneously. In this study, we propose alternative design for 2D thin film coatings, with periodic segments of Ta2O5 and SiO2. The selective optical properties of our design have been optimized in order to improve cooling performance. In this context the transfer matrix formalism was applied to determine the average optical properties. The multilayer conception can provide a high-performance cooling system exceeding 87 W/m2 at an ambient temperature of 300K under direct sunlight, giving to a temperature reduction of 20 °C. More than 95 % of the solar irradiation can be reflected, and the average emissivity in the sky window is larger than 85 %. We believe the proposed design is suitable for daytime radiative cooling purposes and temperature control applications.

Optimal Fuzzy Logic Control for Temperature Control Based on Social Spider Optimization

Fuzzy Logic Controller (FLC) is useful for many applications like industrial, home, military and medical applications, so one of main application is temperature control of A proposed controller combines the advantages of controller structure and fuzzy inference for air heater temperature control applications. The input variables of the PDFLC-SSO are error and change of error, while its output is the control signal. PDFLC-SSO has seven membership functions. These functions are triangular shaped. Centroid method (CM) is selected for the defuzzification process. The universe of discourse range is used from (-1 to 1) for each input and output. Temperature heater model was utilized to test the controller; the gain factors was tuned using trial and error method and SSO algorithm to reach the optimum response with minimum settling time, minimum peak overshoot and minimum Integral Time Absolute Error (ITAE). Carried out simulations showed an average improvement in measurements using ITAE. ITAE is 7.46% for a constant set-value using PDFLC-SSO, while it is 9.55 for a constant set-value using PDFLC.

Application of Voltage in Dynamic Light Scattering Particle Size Analysis.

Dynamic light scattering (DLS) is a common method for characterizing the size distribution of polymers, proteins, and other nano- and microparticles. Modern instrumentation permits measurement of particle size as a function of time and/or temperature, but currently there is no simple method for performing DLS particle size distribution measurements in the presence of applied voltage. The ability to perform such measurements would be useful in the development of electroactive, stimuli-responsive polymers for applications such as sensing, soft robotics, and energy storage. Here, a technique using applied voltage coupled with DLS and a temperature ramp to observe changes in aggregation and particle size in thermoresponsive polymers with and without electroactive monomers is presented. The changes in aggregation behavior observed in these experiments were only possible through the combined application of voltage and temperature control. To obtain these results, a potentiostat was connected to a modified cuvette in order to apply voltage to a solution. Changes in polymer particle size were monitored using DLS in the presence of constant voltage. Simultaneously, current data were produced, which could be compared with particle size data, to understand the relationship between current and particle behavior. The polymer poly(N-isopropylacrylamide) (pNIPAM) served as a test polymer for this technique, as pNIPAM's response to temperature is well-studied. Changes in the lower-critical solution temperature (LCST) aggregation behavior of pNIPAM and poly(N-isopropylacrylamide)-block-poly(ferrocenylmethyl methacrylate), an electrochemically active block-copolymer, in the presence of applied voltage are observed. Understanding the mechanisms behind such changes will be important when trying to achieve reversible polymer structures in the presence of applied voltage.

Extended State Filter Based Disturbance and Uncertainty Mitigation for Nonlinear Uncertain Systems With Application to Fuel Cell Temperature Control

The filter design for nonlinear uncertain systems is quite challenging since efficient estimation is required against stochastic noises, nonlinear uncertain dynamics as well as their concurrent effects. To this end, this article develops a novel filter algorithm by augmenting the disturbance as well as unknown nonlinear dynamics as an extended state and constructing consistent Kalman–Bucy algorithm. The proposed extended state based Kalman–Bucy filter (KBF) is shown to be of bounded estimation error, and the estimation accuracy can be online evaluated. More importantly, the estimation of asymptotic minimum variance is realized in condition that the changing rate of uncertainty approaches to zero. Therefore, the proposed extended state filter enables effective mitigation of disturbance and unknown nonlinear dynamics in real time by feedback control. The proposed algorithm is experimentally verified via a temperature control application in proton exchange membrane fuel cell, in which the thermocouple noise and the electrochemical uncertainty are seriously presented. The temperature variation of the extended state based KBF-based control is greatly reduced, in comparison with the conventional control. The results in this article depict a promising prospect of the proposed method for industrial control applications to handle both noises and nonlinear uncertain dynamics.

Research on temperature control of heating furnace with intelligent proportional integral derivate control algorithm

In view of the problems of large overshoot and large oscillation frequency in cur?rent furnace temperature control, based on the development of intelligent control theory, expert control, fuzzy control, and neural network control in intelligent control theory are combined with proportional integral derivative (PID) control. The intelligent PID control algorithm is used to carry out numerical simulation and experimental research on these several control algorithms. The results show that the adjustment effect of the intelligent PID control algorithm is significantly better than the traditional PID control algorithm. Among them, the fuzzy self-tuning PID control algorithm and the fuzzy immune PID control algorithm are feasible in the application of furnace temperature control. The neural network PID control algorithm It also has good development and application potential.

A Study of the Influence of Stochastic Fractional-Order Delay Dynamics in a Networked Control System

Stochastic communication delays are present in networked control systems and have a significant influence over its closed-loop performance and stability. These delays are time-variant and have infinite variance, indicating fractional-order behavior that can be modeled using α-stable distribution. This paper presents a quantitative analysis of the effects of fractional-order α-stable distribution random communication delays in a networked control system for a temperature control application. The networked closed-loop system assessment is performed using four different controllers. Two integer order PI controllers tuned using classic tuning methods, and two fractional-order PI controllers tuned using standard tuning rules for fractional-order system. One hundred numerical simulation experiments are performed, modeling the random communication delays between the plant and controller using an α-Stable distribution with different α values. Obtained results show that fractional-order controllers can deal better with time-variant fractional-order random communication delays that follows an α-Stable distribution compared with the integer-order controllers.

Comparative Study on Control Methods for Air Conditioning of Industrial Paint Booths

It is of great importance that each product in industrial production facilities is to be produced in the same quality and standard. Especially in the automotive industry, the painting process needs to be done under certain environmental conditions according to the paint properties used. Therefore, the temperature, humidity and air quality values of the paint booth are very important for a quality painting operation. In this study, adaptive control has been proposed to control of one-zone heating-ventilation system for the paint booths. The system has been modelled by using the Matlab/Simulink. Performance of the proposed control method has been compared with conventional control methods such as On/Off, PID, fuzzy logic in terms of accuracy, efficiency and response time. Simulation results show that the proposed adaptive control is effective in the Heating, Ventilating, and Air Conditioning (HVAC) systems temperature control applications. In addition, energy efficiency in HVAC systems has been provided with the proposed control model. Furthermore, thermal analysis of the system has been done to corroborate simulation results.

Carbon nanotube-Cu foam hybrid reinforcements in composite phase change materials with enhanced thermal conductivity

Organic phase change materials (PCM) have been regarded as one of the most promising candidates for the application of energy storage and temperature control due to their advantages in latent heat. However, their intrinsically low thermal conductivity (λ) is the Achilles heel, and the most common solution is to utilize thermal conductive reinforcements to fabricate composite PCMs. The research focus remains how to promote the efficiency of thermal conductive reinforcements. Here, a CNT-Cu foam hybrid reinforcement was fabricated through a high temperature tube furnace process. Different from conventional carbon film coated metal foam, CNTs with the length comparable to the pore size were radially grown on the surface of Cu foam with Ni catalysts, which can not only reduce the low-λ regions inside the foam skeleton, but also connect every branches of the foam to improve the integrity of the whole reinforcement, and the thermal conductivity of the composite was promoted to 3.49 W·m−1·K−1 from 0.105 W·m−1·K−1 of paraffin. Moreover, this reinforcement exhibited abilities to compensate the loss of latent heat and suppress the supercooling of the composite, indicating their great prospects in the application of phase change energy storage and temperature control.

Robust control for time‐fractional diffusion processes: application in temperature control of an alpha silicon carbide cutting tool

Different real-world processes can be described by a linear model parameterised with respect to the process operating point, as an uncertain parameter. The family of transport processes with long memory is a kind of these processes which are characterised by the parameterised time-fractional diffusion equations. This study proposes a generalised iso-damping feature for achieving the phase margin invariance regardless of the uncertain parameter variations in control of time-fractional diffusion processes. Also, the study suggests an analytical method to tune stabilising fractional-order proportional–integral/proportional–derivative controllers for adjusting a desired value for the phase margin at a desired gain crossover frequency, while the proposed robustness criterion is satisfied in control of time-fractional diffusion processes. Furthermore, conditions for solvability of the problem and stability of the obtained control system are analytically derived. Finally, an example on robust temperature control of the cutting edge in alpha silicon carbide cutting tools is presented to confirm the effectiveness of the obtained achievements.

Fabrication of magnetic phase change n-eicosane @ Fe3O4/SiO2 microcapsules on wood surface via sol-gel method

Microencapsulated phase change material (MPCM) has been recognized as one of the best technologies to improve energy efficiency and absorb redundant energy. However, magnetic phase change energy storage performance has rarely been applied on wood. In this paper, magnetic microencapsulated phase change energy storage composite wood was successfully prepared through a sol-gel method which microcapsules containing n-eicosane as the core and Fe3O4/SiO2 composite material as the shell were adhered on wood surface. As a result, microcapsules with an average diameter of 2.5 μm were adhered to the wood surface through hydrogen bonds. Magnetic microencapsulated phase change energy storage composite wood exhibited a magnetism of 3.7 emu/g and energy storage performance of ΔHc 172.5 J/g and ΔHm 170.9 J/g, suggesting the as-prepared composite wood is a probable candidate for temperature control application in furniture field.

Passive temperature control based on a phase change metasurface

In this paper, a tunable mid-infrared metasurface based on VO2 phase change material is proposed for temperature control. The proposed structure consisting of a VO2/SiO2/VO2 cavity supports a thermally switchable Fabry-Perot-like resonance mode at the transparency window of the atmosphere. Theoretically, the radiative cooling power density of the proposed metasurface can be switched to four-fold as the device temperature is below/above the phase change temperature of VO2. Besides radiative cooling, a passive temperature control application based on this huge cooling power switching ability is theoretically demonstrated. We believe the proposed device can be applied for small radiative cooling and temperature control applications.

Rancang Bangun Pengatur Suhu dan Sirkulasi Udara di Smoking Room

In this study, the application of temperature and air circulation control in the smoking room using a microcontroller. The Sensors applied to this Prototype are LM35 and DT-Sense CO. The method used design a controller and then apply it to the microcontroller. The sensor has been tested on a miniature smoking room. The results show sensors can work and good, although cigarette smoke and the temperature of the room changes, so air quality in the smoking room can be maintained.
 Index Term-Cigarette smoke, CO, automation, microcontroller, temperature sensor, smoke sensor

Impression creep test of a P91 steel: a round robin programme

The process of standardisation of small specimen creep testing techniques, specifically the impression creep test requires the repeatability of the test method. In this study it is accomplished through a round robin programme involving four different labs which have slightly different test set-ups adhering to predefined recommendations stated in previous work. The labs all conducted the same stepped stress test on a reference heat of grade 91 power plant steel and the displacement traces of the tests are analysed to outline the effects of different test set-ups and their efficacies. Main differences are in temperature control and loading application and control.

Study on Design and Construction Technology of Self-regulating Asphalt Mixture

At present, there is no mature technology for using phase change modifier in asphalt mixture. This paper is based on the previous research of temperature regulation and performance of self regulating asphalt mixture, according to the application of temperature control, road characteristic and construction experience of self regulating asphalt mixture in cold area, put forward the mix proportion design method and construction technology of self-regulating asphalt mixture. It is the first time to clearly put forward the construction process and quality control method of self regulating mixture.

Experimental investigation on controllable loop thermosyphon with a reservoir

The controllable loop thermosyphons (CLTs) can be widely applied in temperature control applications, such as cool-storage refrigerators powered by solar energy or electricity with the TOU (time of use) price. However, the performance of the CLT requires further optimization. In this study, a new CLT is designed and reservoir structure is adopted to improve the steady-state heat transfer performance. Three control modes are available to control the start-stop of the CLT and their influence on the start-stop performances is investigated. For each control mode, the valve location and test conditions are varied; results are compared and analyzed. Control mode A performs well and is affected weakly by the valve location. The control ability of control mode B is acceptable only when the valve is located on the lower liquid line. The start-stop performance of control mode C is better than that of control mode A and B; and with its best valve location, the CLT starts up quickly in approximately 25s and stops in about 75s under various test conditions. The experimental investigation revealed that control mode C is the optimal one and that valves are better to be installed in lower positions for all control modes.

Automatic extruder for processing recycled polymers with ultrasound and temperature control system

Melt viscosity is one of the main factors affecting product quality in extrusion processes particularly with regard to recycled polymers. However, due to wide variability in the physical properties of recycled feedstock, it is difficult to maintain the melt viscosity during extrusion of polymer blends and obtain good quality product without generating scrap. This research investigates the application of ultrasound and temperature control in an automatic extruder controller, which has ability to maintain constant melt viscosity from variable recycled polymer feedstock during extrusion processing. An ultrasonic modulation system has been developed and fitted to the extruder prior to the die to convey ultrasonic energy from a high power ultrasonic generator to the polymer melt. Two separate control loops have been developed to run simultaneously in one controller: the first loop controls the ultrasonic energy or temperature to maintain constant die pressure, the second loop is used to control extruder screw speed to maintain constant throughput at the extruder die. Time response and energy consumption of the control methods in real-time experiments are also investigated and reported this paper.