Temperature Control Method Research Articles

Research on temperature control of proton exchange membrane electrolysis cell based on MO‐TD3

AbstractTo solve the problem of temperature control in proton exchange membrane electrolytic cell (PEMEC), this paper presents a temperature control method based on multi‐experience pool probability playback and Ornstein‐Uhlenbeck noise‐twin delay depth deterministic strategy gradient. Firstly, considering the influence of water supply, anode and cathode pressure, and natural heat dissipation on temperature, a refined thermal model of PEMEC is established and transformed into a Markov model under the framework of deep reinforcement learning (DRL). Then, to solve the training instability and poor control effect of DRL caused by inertia delay of the PEMEC temperature control system, multi‐empirical pool probability playback and Ornstein‐Uhlenbeck random process noise techniques are introduced on the basis of the traditional DRL method. Finally, the simulation and hardware‐in‐the‐loop experience results show that the proposed method outperforms other advanced methods.

Performance investigation of a low-power Hall thruster fed on iodine propellant

The common propellants used for electric thrusters, such as xenon and krypton, are rare, expensive, and difficult to acquire. Solid iodine attracts much attention with the advantages of low cost, extensive availability, low vapor pressure, and ionization potential. The performance of a low-power iodine-fed Hall thruster matched with a xenon-fed cathode is investigated across a broad range of operation conditions. Regulation of the iodine vapor’s mass flow rates is stably achieved by using a temperature control method of the iodine reservoir. The thrust measurements are finished utilizing a thrust target during the tests. Results show that thrust and anode-specific impulse increase approximately linearly with the increasing iodine mass flow rate. At the nominal power of 200 W class, iodine mass flow rates are 0.62 and 0.93 mg/s, thrusts are 7.19 and 7.58 mN, anode specific impulses are 1184 and 826 s, anode efficiencies are 20.8% and 14.5%, and thrust to power ratios are 35.9 and 37.9 mN/kW under the conditions of 250 V, 0.8 A and 200 V, 1.0 A, respectively. The operating characteristics of iodine-fed Hall thruster are analyzed in different states. Further work on the measurements of plasma characteristics and experimental optimization will be carried out.

A novel heating strategy and its optimization of solar–air source heat pump heating system for rural buildings in northwest China

In the rural areas of Northwest China, the utilization of clean and renewable energy is deemed a crucial measure for reducing building energy consumption and environmental pollutant emissions. This paper focuses on constructing a simulation platform for a solar-assisted air source heat pump heating system. A rural residential building in Yongshou County, Shaanxi Province, serves as an illustrative example. A novel flexible temperature control method with a feedback controller in sub-area and period is proposed in this paper, alongside the selection of three distinct objective functions aimed at optimizing the heating system. The simulation results indicate an average temperature of 17.0 °C throughout the heating cycle, with a peak temperature of 18.7 °C. Moreover, the solar fraction is measured at 25.11%, underscoring the significance of collector area and heat storage tank volume as primary factors in system design. The results also demonstrate that across various optimization objectives, the life cycle cost optimization scheme yields greater economic benefits, while the target building unit heating cost optimization scheme boasts the shortest static payback period and lowest unit heating cost. Conversely, the solar fraction optimization scheme stands out for its superior environmental benefits. These findings offer valuable insights for the design of heating systems tailored to diverse objectives.

A Temperature Control Method of Lysozyme Fermentation Based on LRWOA-LSTM-PID

In order to overcome the difficulty of parameter tuning caused by the large lag and time-varying nonlinearity of the tank for lysozyme fermentation, a temperature control method based on LRWOA-LSTM-PID is proposed in this paper. Firstly, according to the intrinsic mechanism of the fermenter, a temperature mechanism model based on a dynamic equation is designed, which can better reflect the temperature changes in the fermenter. Secondly, a Proportional Integral Derivative (PID) parameter tuning method based on a Long-Short Term Memory Network (LSTM) is proposed, which takes advantage of the ability of LSTM to learn time sequence information and obtains the variation trend between error sequences under continuous time sampling, thereby adjusting network weights more reasonably and accelerating PID parameter tuning. Finally, a Whale Optimization Algorithm (WOA) based on the Lévy flight and random walk strategy (LRWOA) is proposed for the initialization of LSTM parameters; this algorithm has excellent optimization capabilities and overcomes the problem of LSTM falling into local optimal solutions prematurely during parameter randomization. The results show that the method proposed in this paper can achieve rapid tuning of PID parameters, thereby improving the convergence speed of the system and reducing system overshoot.

Research on improved partial format MFAC greenhouse temperature control method based on low energy consumption optimization

Temperature is critical to the growth of crops in agricultural greenhouses. Thus, designing a greenhouse temperature controller that maximizes energy savings while maintaining control accuracy is very important. This paper proposes an improved partial format model-free adaptive control method and designs a greenhouse temperature controller based on this method to balance control accuracy and energy consumption. Firstly, a limited energy consumption term is added to the control input cost function of the traditional partial format model-free adaptive control to penalize excessive control input. We derive an improved partial format model-free adaptive control input algorithm and design a greenhouse temperature controller using this algorithm. Then, the controller's sensitive parameters are selected using a Monte Carlo-based parameter sensitivity method. Finally, the whale optimization algorithm is used to optimize the sensitive parameters. The insensitive parameters are set according to experience. This paper, a theoretical study based on simulated experiments, proves the convergent tracking error of the proposed improved partial format model-free adaptive algorithm. Simulation results show that the improved controller minimizes energy consumption while ensuring control accuracy, reducing power consumption by 12.35 % compared to the traditional controller.

A temperature control method of hot-bar soldering based on extended Kalman filter

PurposeThis study aims to introduce a novel technique for nonlinear sensor time constant estimation and sensor dynamic compensation in hot-bar soldering using an extended Kalman filter (EKF) to estimate the temperature of the thermocouple.Design/methodology/approachTemperature optimal control is combined with a closed-loop proportional integral differential (PID) control method based on an EKF. Different control methods for measuring the temperature of the thermode in terms of temperature control, error and antidisturbance are studied. A soldering process in a semi-industrial environment is performed. The proposed control method was applied to the soldering of flexible printed circuits and circuit boards. An infrared camera was used to measure the top-surface temperature.FindingsThe proposed method can not only estimate the soldering temperature but also eliminate the noise of the system. The performance of this methodology was exemplary, characterized by rapid convergence and negligible error margins. Compared with the conventional control, the temperature variability of the proposed control is significantly attenuated.Originality/valueAn EKF was designed to estimate the temperature of the thermocouple during hot-bar soldering. Using the EKF and PID controller, the nonlinear properties of the system could be effectively overcome and the effects of disturbances and system noise could be decreased. The proposed method significantly enhanced the temperature control performance of hot-bar soldering, effectively suppressing overshoot and shortening the adjustment time, thereby achieving precise temperature control of the controlled object.

Room temperature chirality switching and detection in a helimagnetic MnAu2 thin film

Helimagnetic structures, in which the magnetic moments are spirally ordered, host an internal degree of freedom called chirality corresponding to the handedness of the helix. The chirality seems quite robust against disturbances and is therefore promising for next-generation magnetic memory. While the chirality control was recently achieved by the magnetic field sweep with the application of an electric current at low temperature in a conducting helimagnet, problems such as low working temperature and cumbersome control and detection methods have to be solved in practical applications. Here we show chirality switching by electric current pulses at room temperature in a thin-film MnAu2 helimagnetic conductor. Moreover, we have succeeded in detecting the chirality at zero magnetic fields by means of simple transverse resistance measurement utilizing the spin Berry phase in a bilayer device composed of MnAu2 and a spin Hall material Pt. These results may pave the way to helimagnet-based spintronics.

Implementasi Sistem Monitoring Alat Pengering Biji Kopi Berbasis IoT (Internet of Things)

Indonesia holds the third position in global coffee bean supply, with a 3.3% increase in demand in 2021 according to ICO data. In line with ICO Resolution 407, coffee bean quality must be high, indicated by a 12.5% moisture content through drying processes. Mechanical drying is faster than traditional methods, thus becoming the focus of this research. This study implements an IoT-based monitoring system for coffee bean drying equipment. The aim is to create and implement a monitoring system for temperature (0°C - 70°C) and electrical energy consumption (kWh) in coffee bean drying, displayed on the ThingSpeak dashboard. Test results show that the temperature monitoring system using DHT22 sensors at the inlet and outlet of the rotary dryer tube has an average error of 2.1%. The energy monitoring system using PZEM-004T has a 0% energy measurement error. These results indicate a reliable monitoring system that enables remote monitoring via the internet. Furthermore, the study tests manual (on/off) and fuzzy logic control methods to achieve 12% moisture content in coffee beans. The fuzzy logic control method demonstrates better temperature stability and 11.2% cost savings in operational expenses. This research benefits coffee farmers by facilitating efficient monitoring of the bean drying process, and recommends the use of the fuzzy logic control method for stable temperature and lower operational costs.

Evaluation of a thermoregulatory intravascular catheter in critically ill burns patients.

Patients with severe burns are at high risk of thermoregulatory failure. Yet, there is a lack of consensus regarding the optimum approach to temperature dysregulation in patients with severe burns. Intravascular temperature management catheters may offer a superior method of temperature control, but robust data are lacking. In this article, we describe our experience in using a thermoregulatory catheter for temperature management in a tertiary referral burns center. We conducted a single-center, prospective evaluation of the use of a thermoregulatory intravenous catheter system (Thermogard XP®) in critically injured burns patients admitted to our intensive care unit over an 18-month period. Ten patients had a total of 12 catheters inserted. Patient temperatures were maintained between a median low of 36.9 °C and a median high of 38.4 °C while in the intensive care unit. If patients were transferred to theater, the median temperature change was -0.15 °C (interquartile range [IQR] -0.3, 0) if TBSA was ≤50% and -1.45 °C (IQR -2.05, -0.975) if >50%. No surgical procedures were terminated due to intraoperative hypothermia. On return from theater, 72.2% of patients were normothermic with a median temperature of 36.8 °C. Thirty percent of patients developed a thrombotic complication. Overall, the device appeared reliable in achieving and maintaining normothermia for critically ill burns patients manifesting temperature dysregulation. It may also be of benefit to patients expected to show temperature fluctuations during operative procedures. Further research is needed to define whether this represents an improvement over current practice and investigate the thrombus risk associated with such devices.

Temperature control method and verification for spaceborne atomic clock based on phase change technology

The spaceborne atomic clock, as the time reference for navigation signal generation and system ranging, is the core component of the satellite system payload, and temperature stability is one of the main factors affecting the output frequency stability of the atomic clock. To ensure its continuous and stable operation in orbit, the temperature control system needs to provide a good working temperature environment for it. This article takes the high stability temperature control of the rubidium atomic clock in low-Earth inclined orbit as the research background, and conducts research on temperature control methods and phase change devices based on phase change technology. Simulation analysis and in-orbit telemetry data show that, by utilizing the temperature stability characteristic during the phase change process, the phase change temperature control system effectively suppresses the temperature fluctuations of the rubidium atomic clock caused by drastic changes in the space thermal environment.

Economic Model Predictive Control in Buildings Based on Piecewise Linear Approximation of Predicted Mean Vote Index

Energy shortage is a challenge for many countries, and building energy consumption accounts for a considerable proportion of global energy consumption. The main work of this paper is to optimize the energy consumption of heating, ventilating, and air conditioning (HVAC) systems in buildings based on economic model predictive control (EMPC). The cost in EMPC design includes energy consumption and predicted mean vote (PMV), which is an index that evaluates the thermal comfort of indoor occupants. In order to model the nonlinearity of the PMV index, we propose a lattice piecewise linear (PWL) approximation, which has high approximation precision and facilitates the resulting optimization problem, which is basically a piecewise quadratic programming problem. For the piecewise quadratic programming, we propose a descent algorithm that converges quickly and scales well with the length of the prediction horizon in the EMPC problem. The experimental results demonstrate that the proposed method saves 19.78% of the electricity cost compared to the conventional control strategy and significantly increases indoor comfort. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> — The motivation of this article is to provide a control strategy to reduce building energy consumption and ensure indoor thermal comfort. In most of the existing methods for air conditioning temperature control, the occupants’ comfort hasn’t been considered. In this paper, thermal comfort is described by the PMV index, which is basically nonlinear. In order to model the thermal comfort more accurately, in this paper, the PMV index is approximated piecewise linearly in order to meet the requirements of accuracy and computational efficiency. The resulting optimization problem is not hard to solve, and we provide an efficient algorithm for solving this optimization problem. Preliminary simulation experiments demonstrate that this approach is practical, i.e., it achieves energy reduction and ensures thermal comfort. Our strategy, however, has not yet been deployed in real buildings. In future research, we will propose similar techniques for large-scale systems in order to solve energy optimization problems containing multiple thermal zones and realize the proposed technique in real buildings.

Control Method of Temperature for Multi-stack Fuel Cell System

Control Method of Temperature for Multi-stack Fuel Cell System

Fuzzy PID based temperature control method for power transformer coils

Fuzzy PID based temperature control method for power transformer coils

A Flip-count-based Dynamic Temperature Control Method for Constrained Combinatorial Optimization by Parallel Annealing Algorithms

A Flip-count-based Dynamic Temperature Control Method for Constrained Combinatorial Optimization by Parallel Annealing Algorithms

Optimized precision temperature control method and experimental validation for non-uniform discontinuous X-ray telescope

Optimized precision temperature control method and experimental validation for non-uniform discontinuous X-ray telescope

Temperature control system of hot and cold alternating treatment system based on Kalman filter combined with fuzzy logic

Abstract Aiming at the lag, overshoot, easy interference, and other problems of the temperature control of the heat exchanger in the current alternating hot and cold treatment of deep vein thrombosis equipment, a fuzzy temperature control method based on Kalman filtering is proposed to complete the filtering for the measurement noise through Kalman filtering. Finally, based on the fuzzy strategy to achieve fast response and overshoot control of temperature control, we analyze its fuzzy rules and reasoning through the study of fuzzy PID control. By using MATLAB software for simulation and comparison, it is proved that the accuracy of the designed heat exchanger temperature control system is greatly improved, the robustness of the system is better, the response speed is obviously improved, the amount of overshooting is reduced, the regulation time becomes shorter, and there is also a strong inhibition effect on the interference.

Fuzzy PID-based temperature control method for power transformer coils

Fuzzy PID-based temperature control method for power transformer coils

Precise Synergistic Photothermal Therapy Guided by Accurate Temperature‐Dependent NIR‐II Fluorescence Imaging

AbstractPhotothermal therapy (PTT) is considered a promising treatment strategy for solid tumors. However, local hyperthermia (over 45°C) during PTT can cause severe side effects in neighboring healthy tissues. PTT with accurate temperature feedback is a compelling strategy to ablate tumors and reduce side effects, but it still faces challenges. Here, a new kind of phototheranostic nanoparticle, namely 17‐RF@Ag2Se is developed, enabling in vivo NIR‐II fluorescence tracking, PTT and fluorescence nanothermometry as well as synergistic heat‐shock protein (HSP) inhibition. Precise PTT with high spatiotemporal resolution is achieved with the help of the designed NIR‐II fluorescence imaging‐photothermal therapy linkage apparatus. Upon intravenous injection, 17‐RF@Ag2Se is specifically accumulated in tumors targeted by the overexpressed integrin αvβ3, which is monitored by NIR‐II fluorescence imaging of Ag2Se QDs. Further, the release of HSP inhibitor, tanespimycin (17‐AAG), enhances the thermosensitivity of tumor cells. Subsequently, the internal temperature of the tumor is precisely monitored and adjusted during PTT via the temperature‐dependent NIR‐II fluorescence feedback of Ag2Se QDs and the linkage apparatus calibration, thereby achieving efficient and safe tumor PTT. Also, the results present a new method for accurate temperature monitoring and control in vivo, which can be applied to other biomedical studies.

Driving range evaluation of electric vehicle with transcritical CO2 thermal management system under different battery temperature controls

Improper battery temperature will lead to reduced battery discharge efficiency and electric vehicle driving range. Endeavors to find an efficient and precise battery temperature control method for the transcritical CO2 thermal management system of electric vehicles, two evaporation temperature control methods for battery cooling were proposed. First, the effects of the control methods on battery temperature, optimal discharge pressure and coefficient of performance (COP) were simulated under typical operating conditions. Subsequently, a comparative simulation was conducted on the battery temperatures and COP of the two control methods under full cooling conditions. The results revealed that equal evaporation temperature control induced a reduction in battery temperature to 11 °C (suboptimal levels) under conditions of low ambient temperature and vehicle speed. Conversely, while unequal evaporation temperature control could maintain the battery temperature within the optimal range of 20–45 °C, it would result in a maximum COP drop of more than 20% under certain conditions. Furthermore, the effects of the two control methods on driving range under different ambient temperatures and vehicle speeds were studied. The reasults indicated that the ultimate influence of uneuqal evaporation temperature control on the quarterly average driving range was virtually negligible, peaking at 1.35%. Given the dual-objective constraints pertaining to the driving range and the battery cooling performance, it was concluded that uneuqal evaporation temperature control was the optimal choice for direct battery cooling.

Application of Variable Theory Domain Fuzzy Control Algorithm for Room Temperature Control

With the development of automatic control in the HVAC industry, more and more buildings have adopted automatic control of air conditioning, HVAC systems, but most of the control results can not be satisfactory. The research object of this paper is the elevator machine room equipped HVAC, through accurate control of that room temperature can greatly reduce the elevator shutdown caused by the action of the temperature protection circuit, so as to improve the safety of elevator operation. This paper gives three different temperature control methods, establishes the math representation of the temperature system in the machine room, specifically designs the classical PID controllers, Fuzzy PID controllers and variable domain Fuzzy PID controller, and simulates and analyzes the three algorithms respectively, The results indicate that in comparing the above three algorithms, the variable domain fuzzy PID algorithm has an adjustment time of 63s, and the overshooting amount of 0.4%, which is the best among the three control algorithms.