Temperature Control Research Articles

Synthesis and Mechanistic Study of Naphthalimide Derivative Formation via Cu-Mediated Ullmann-Type Reactions.

Cu-mediated Ullmann-type coupling reactions are fundamental to organic synthesis, garnering significant academic and industrial interest since their inception. Optimizing reaction parameters, particularly temperature control, is crucial for maximizing efficiency while maintaining high yields. Bidentate ligands, such as amino acids, have demonstrated potential in facilitating these reactions at lower temperatures (<100 °C). This study explores the Cu-catalyzed Ullmann-type coupling of naphthalimide derivatives with amino acid substitutions. Naphthalimide dyes, known for their diverse applications in bioimaging, solar cells, medicine, and sensors, were selected for their potent anticancer properties. The synthesized compounds were characterized by using 1H NMR, ESI-MS, and melting point analyses. Compounds with significant steric hindrance exhibited lower yields, leading to the development of a novel catalytic system employing l-carnosine as a bidentate ligand, which significantly improved yields. Mechanistic insights, derived from density functional theory calculations, identified "L-complex 3" as the most stable and reactive intermediate during oxidative addition to aryl halides. The oxidative addition transition state "OX1-TS" was found to be the most favorable, with a relatively low energy barrier of 6.13 kcal/mol, suggesting that this step, despite being the rate-limiting stage, is energetically accessible. In contrast, reductive elimination was facilitated by a Cu(III) penta-coordinated intermediate, with a barrier of just 8.34 kcal/mol, making it a more straightforward process. Theoretical findings aligned closely with experimental data, reinforcing the oxidative addition/reductive elimination pathway as the operative mechanism for this reaction.

Application of PID algorithm in temperature control of pig houses farmers' mental health from the perspective of social ecological system and its implications for agricultural production efficiency

This study investigates the application of PID algorithm-based temperature control systems in pig house environmental management and its impact on agricultural production efficiency. Through field experiments conducted at Dongshun Aquaculture Ecological Development Co., Ltd. in Nanping City, Fujian Province, we evaluated the system's effectiveness in energy efficiency, production performance, and animal health. Results show that the PID system achieved 18.5% energy savings, a 9% increase in daily weight gain, and a 7.1% improvement in feed conversion ratio. Additionally, meat quality scores improved by 8.3%, and disease incidence rates decreased by 21.9%. Economic analysis indicates that the system begins to generate a positive return on investment in the second year, with cumulative benefits reaching 192% within five years. These findings highlight the potential of PID temperature control systems in improving pork production efficiency and sustainability, offering a valuable solution for modern pig farming.

Study on the Formation and Mechanical Stability of Retained Austenite in Complex Phase Steel with High Formability

Herein, a 1300 MPa grade complex phase steel with high formability (CH) is developed, which is achieved through the formation of cementite during pretreatment and the control of austempering temperature to enhance the stability of retained austenite (RA). Due to the insufficient diffusion of Mn during cementite dissolution, Mn enrichment enhances the mechanical stability of austenite, thereby increasing austenite content at room temperature. As the austempering temperature increases from 340 °C to 400 °C, the RA content increases, but its stability decreases significantly. Compared with the content of RA, its stability is more critical for enhancing plasticity. RA formed at lower austempering temperatures is highly stable, enlarging the strain range of the transformation‐induced plasticity effect and improving material plasticity. The experimental steel achieves optimal plasticity while maintaining strength when overaged at 360 °C. Specifically, the yield strength is 963 MPa, the ultimate tensile strength is 1394 MPa, and the total elongation is 14.0%.

780 nm Narrow Linewidth External Cavity Diode Laser for Quantum Sensing

To meet the demands of laser communication, quantum precision measurement, cold atom technology, and other fields for narrow linewidth and low-noise light sources, an external cavity diode laser (ECDL) operating in the wavelength range around 780 nm was set up with a Fabry–Pérot etalon (F–P) and an interference filter (IF) in the experiment. The interference filter type ECDL (IF–ECDL) with butterfly-style packaging configuration has continuous wavelength tuning within a specified range through precise temperature and current control and has excellent single-mode characteristics. Experimental results indicate that the output power of the IF–ECDL is 14 mW, with a side-mode suppression ratio (SMSR) of 54 dB, a temperature-controlled mode-hop-free tuning range of 527 GHz (1.068 nm), and an output linewidth of 570 Hz. Compared to traditional lasers operating at 780 nm, the IF–ECDL exhibits narrower linewidth, lower noise, and higher spectral purity, and its dimensions are merely 25 × 15 × 8.5 mm3 weighing only 19.8 g, showcasing remarkable miniaturization and lightweight advantages over similar products in current research fields.

Biogas Production from a Solar-Heated Temperature-Controlled Biogas Digester

This research paper explores biogas production in an underground temperature-controlled fixed dome digester and compares it with a similar uncontrolled digester. Two underground fixed-dome digesters, one fitted with a solar heating system and a stirrer and the other one with an identical stirrer only, were batch-fed with cow dung slurry collected from the University of Fort Hare farm and mixed with water in a ratio of 1:1. The solar heating system consisted of a solar geyser, pex-al-pex tubing, an electric ball valve, a water circulation pump, an Arduino aided temperature control system, and a heat exchanger located at the centre of the digester. Both the digesters were intermittently stirred for 10 min every 4 h. The digester without a heating system was used as a control. Biogas production in the two digesters was compared to assess the effect of solar heating on biogas production. The total solids, volatile solids, and the chemical oxygen demand of the cow dung used as substrate were determined before and after digestion. These were compared together with the cumulative biogas produced and the methane content for the controlled and uncontrolled digesters. It was observed that the temperature control system kept the slurry temperature in the controlled digester within the required range for 82.76% of the retention period, showing an efficiency of 82.76%. Some maximum temperature gradients of 7.0 °C were observed in both the controlled and uncontrolled digesters, showing that the stirrer speed of 30 rpm was not fast enough to create the needed vortex for a uniform mix in the slurry. It was further observed that the heat from the solar geyser and the ground insulation were sufficient to keep the digester temperature within the required temperature range without any additional heat source even at night. Biogas yield was observed to depend on the pH with a strong coefficient of determination of 0.788 and 0.755 for the controlled and uncontrolled digesters, respectively. The cumulative biogas was 26.77 m3 and 18.05 m3 for controlled and uncontrolled digesters, respectively, which was an increase of 33%. The methane content increased by 14% while carbon dioxide decreased by 10% from the uncontrolled to the controlled scenario. The percentage removal of the TS, VS, and COD was 66.26%, 76.81%, and 74.69%, respectively, compared to 47.01%, 60.37%, and 57.86% for the uncontrolled situation. Thus, the percentage removal of TS, VS, and COD increased by 19.25%, 16.44%, and 16.89%, respectively.

Fractional modeling of bioconvection in Jeffrey nanofluids with gyrotactic organisms

AbstractThe current study examines how mass and heat transfer affect mobility of Jeffrey fluid while taking sun radiation across the vertical plate into account. In the polyvinyl alcohol water base fluid, the study combines gyrotactic organisms with copper nanoparticles. Microorganisms classified as gyrotactic respond to gravitational and viscous forces by swimming and orienting themselves, which results in the formation of patterns known as bioconvection, which is the result of the collective movement of these microorganisms. The main goals are to address the growing uses of solar plates by creating a unique mathematical model for flow and thermal properties of the parabolic trough solar collector (PTSC) installed on solar panel. Sunlight is directed onto a single focal line by curved mirrors in PTSCs, which heat the fluid moving over the plate at this focused line. The momentum, heat, and mass equations are solved by the model using Fourier and Fick's laws. The Laplace transform is then used to convert the solution sets into dimensionless Partial differential equation (PDE) for the velocity, energy, and mass fields. The innovative aspect of this model is its in‐depth examination of non‐Newtonian nanofluids, which are boosted by the addition of gyrotactic organisms and copper nanoparticles to increase heat transfer efficiency. The impacts of several factors on flow characteristics, including the Lewis number, mass Grashof number, Grashof number for bioconvection, magnetic and electric parameters, Peclet number, chemical reaction parameter, and Prandtl number, are shown graphically. Increasing the radiation parameters and volume fraction results in a noticeable improvement in the temperature profile. By demonstrating the superior heat transfer capabilities of non‐Newtonian nanofluids in solar energy applications, this work advances the field. It is particularly relevant to microchip cooling, solar energy systems, and thermal energy systems. In summary, the work provides a comprehensive model that advances our understanding of heat and mass transfer in non‐Newtonian nanofluids that are exposed to ambient sunlight. In the future, the model will be employed in real solar energy systems to confirm its effectiveness. The findings have applications in the development of temperature control technology and solar energy systems that are more effective.

Exhaust Temperature Control of Double Tail Flue Boiler

According to the structural characteristics of a double tail flue boiler in a power plant, the cause of the fault was found through objective theoretical analysis, and corresponding improvement measures were formulated. The problem of abnormally high boiler exhaust temperature was effectively solved, the economy and safety of boiler operation were improved, and the normal operation of the boiler was ensured.

Abstract Su1202: The utility of post cardiac arrest temperature control protocol according to the severity of hypoxic encephalopathy based on amplitude-integrated electroencephalography findings

Introduction: The TTM2 trial showed that active fever prevention below 37.5°C and hypothermia at 33°C had similar outcomes in out-of-hospital post cardiac arrest patients. However, the patients in the trial had mild hypoxic encephalopathy, and the effects of hypothermia may vary with its severity. We previously reported that amplitude-integrated electroencephalography (aEEG) findings after the return of spontaneous circulation can be used to categorize the severity of hypoxic encephalopathy (Crit Care. 2018;22:226). In September 2022, we adopted a new temperature control protocol wherein the target temperature was set based on aEEG findings. This study examined changes in outcomes before and after implementing this new protocol. Methods: We assessed out-of-hospital cardiac arrest patients who received post cardiac arrest care in our emergency intensive care unit between March 2021 and February 2024. We divided the patients into two groups: before (B) and after (A) the introduction of the new protocol. We classified the patients into categories 1 (C1) to 4 (C4) based on the severity of hypoxic encephalopathy (Figure 1). All patients in group B were treated with hypothermia at 34°C. In group A, patients in C1 were treated with active fever prevention, and those in C2–C4 received hypothermia at 34°C (Figure 2). Primary outcome was favorable neurological outcomes (cerebral performance categories of 1 or 2) at hospital discharge. Secondary outcome was the duration of mechanical ventilation. Results: A total of 160 patients were included. The median age was 62 years and 105 (66%) patients had cardiac etiology. Fifty-five (34%) patients underwent extracorporeal cardiopulmonary resuscitation. The median cardiac arrest time was 29 min. Groups B and A comprised 57 and 103 patients, respectively. C1 category comprised 20 and 28 patients in groups B and A, respectively. The rate of favorable neurological outcomes was 35% in both B and A groups (p=1.00). Regarding C1 patients, the rates were 90% and 86% in B and A groups (p=1.00). Median duration of mechanical ventilation was 5 and 3 days in group B and A, respectively (p=0.11). Conclusion: Neurological outcomes before and after introducing the new protocol were similar. Management of patients with mild hypoxic encephalopathy can be simplified with active fever prevention. A temperature control protocol based on the severity of hypoxic encephalopathy using aEEG findings is feasible for emergency physicians.

Ethanol Production From Sugarcane Molasses: Effects of Ph, Supplementation, and Refrigeration in Simulated Industrial Conditions at a Microdistillary

Objective: This study aims to evaluate the effects of pH, ammonium sulfate supplementation, and refrigeration on fermentation performance in sugarcane molasses, with the goal of optimizing ethanol production under simulated industrial conditions. Theoretical Framework: The research builds on key concepts in biofuel production, emphasizing the role of pH, nutrient supplementation, and temperature control in influencing yeast metabolism and fermentation efficiency. Theories on enzymatic activity and nutrient absorption (Vidal et al., 2013; Gutierrez, 1993) provide the foundation for understanding the interactions between these factors. Method: A full 2³ factorial design was employed, evaluating the effects of pH (3.5 and 5.0), supplementation (0.0 and 1.0 g/L), and refrigeration (with or without) on fermentation efficiency, process efficiency, ethanol productivity, and substrate-to-cell conversion in a microdistillery. Analytical methods included spectrophotometry, refractometry, and chromatography. Results and Discussion: The results indicate that fermentation conditions with pH 3.5, without supplementation, and with refrigeration yielded the best performance, with significant increases in ethanol productivity and fermentation efficiency. The interaction between variables suggests that these factors should be considered jointly to optimize the process. Research Implications: The findings offer practical insights for improving fermentation in industrial biofuel production, particularly in optimizing conditions for ethanol yield and process efficiency under near-industrial conditions. Originality/Value: This study contributes by using a microdistillery to simulate industrial conditions, providing more accurate data for scaling ethanol production. It adds value by highlighting how specific combinations of pH, supplementation, and refrigeration can improve biofuel sustainability.

From coffee waste to nutritional gold: bioreactor cultivation of single‐cell protein from Candida sorboxylosa

AbstractBACKGROUNDIndustrial effluents are continuously discharged into the environment. These wastewaters contain valuable compounds that can be reused for biotechnological applications. Coffee wastewater (CWW) is a powerful effluent that can be used for single‐cell protein (SCP) production reaching important content (up to 80%). Several yeast species can be used for SCP production, but Candida species are commonly applied for this purpose (17 species reported including the novel C. sorboxylosa). In addition, SCP can be produced in bioreactors under controlled conditions under three operation modes. Thus, batch mode is frequently used but continuous mode presents interesting advantages in economic terms, although it has been poorly applied in SCP production.RESULTSThe initial evaluation under batch operation mode showed that volumetric oxygen transfer coefficient (kLa of 101 h−1) improved biomass production (1.39 g L−1) and SCP yield (59.9%) in C. sorboxylosa. Thus, continuous mode was established at selected kLa and feeding with optimized medium composed of 87.5% (v/v) CWW, 1.38 g L−1 yeast extract, and 7.24 g L−1 (NH4)2SO4, in order to provided necessary nutrients. In this sense, the process presented higher values in dry cell weight and SCP productivity (0.57 and 0.29 g L−1·h, respectively), achieving a 3.35‐ and 2.90‐fold increase in biomass and protein productivity, respectively, compared to batch mode. The SCP from C. sorboxylosa exhibited an interesting essential amino acid profile under continuous mode (33.704%).CONCLUSIONThe bioprocess highlights several advantages during bioreactor cultivation, including: (i) reduced energy consumption for temperature control; (ii) successful establishment of an initial continuous operation mode with promising performance; and (iii) SCP from C. sorboxylosa exhibited a notable composition of essential amino acids, which could be beneficial for potential use in animal feed. © 2024 Society of Chemical Industry (SCI).

EPI proton resonant frequency temperature mapping at 0.5T in the brain: Comparison to single-echo gradient recalled echo.

Evaluate the use of both single-echo gradient recalled echo (SE-GRE) and EPI approaches to creating temperature maps on a mid-field head-only scanner, both in vivo and on a tissue mimicking gel. Three 2D protocols were investigated (an SE-GRE, single-shot EPI, and an averaged single-shot EPI). The protocols used either a gradient recalled acquisition or an echo planar acquisition, with EPI parameters optimized for the longer at lower field-strengths. Phantom experiments were conducted to evaluate temperature tracking while cooling, comparing protocol to measurements from an optical fiber thermometer. Studies were performed on a 0.5T head only MR scanner. Temperature stability maps were produced in vivo for the various protocols to evaluate precision. The use of an EPI protocol for thermometry improved temperature precision in a temperature control phantom and provided an 18% improvement in temperature measurement precision in vivo. Temperature tracking using a fast (<2 s) update rate EPI thermometry sequence provided a similar precision to the slower SE-GRE protocol. While SE-GRE PRF thermometry shows good performance, EPI methods offer improved tracking precision or update rate, making them a better option for thermometry in the brain at mid-field.

A Measurement Device for the Normal Spectral Emissivity of Materials Under Low-Temperature and Vacuum Conditions

Based on parallel light, a device for measuring sample emissivity under vacuum and low temperature was established. In this paper, a new emissivity measurement formula was designed, which replaces the derivation of Kirchhoff’s law of thermal radiation. The device is designed with a light-weight blackbody, an improved cooling speed, and an improved PID temperature control system to achieve a good temperature stability, close to 1 mK. The device is capable of measuring within a wavelength range of 4 μm to 16 μm. The results of the uncertainty assessment show that the uncertainty of the normal emissivity is better than 1.6% in the range of 4 μm to 7 μm, and better than 0.6% in the range of 7 μm to 14 μm (k = 1) at 0 °C.

Energy Sources and Battery Thermal Energy Management Technologies for Electrical Vehicles: A Technical Comprehensive Review

Electric vehicles are increasingly seen as a viable alternative to conventional combustion-engine vehicles, offering advantages such as lower emissions and enhanced energy efficiency. The critical role of batteries in EVs drives the need for high-performance, cost-effective, and safe solutions, where thermal management is key to ensuring optimal performance and longevity. This study is motivated by the need to address the limitations of current battery thermal management systems (BTMS), particularly the effectiveness of cooling methods in maintaining safe operating temperatures. The hypothesis is that immersion cooling offers superior thermal regulation compared to the widely used indirect liquid cooling approach. Using MATLAB Simulink, this research investigates the dynamic thermal behaviour of three cooling systems, including air cooling, indirect liquid cooling, and immersion cooling, by comparing their performance with an uncooled battery. The results show that immersion cooling outperforms indirect liquid cooling in terms of temperature control and safety, providing a more efficient solution. These findings challenge the existing literature, positioning immersion cooling as the optimal BTMS. The main contribution of this paper lies in its comprehensive evaluation of cooling technologies and its validation of immersion cooling as a superior method for enhancing EV battery performance.

Weakening of global terrestrial carbon sequestration capacity under increasing intensity of warm extremes.

The net ecosystem exchange (NEE), determining terrestrial carbon sequestration capacity, is strongly controlled by climate change and has exhibited substantial year-to-year fluctuations. How the increased frequency and intensity of warm extremes affect NEE variations remains unclear. Here, we combined multiple NEE datasets from atmospheric CO2 inversions, Earth system models, eddy-covariance data-driven methods and climate datasets to show that the terrestrial carbon sequestration capacity is weakened during warm extreme occurrences over the past 40 years, primarily contributed by tropical regions (81% ± 48%). The underlying mechanism can be rooted in the overwhelmingly decreased trend of gross primary productivity compared with terrestrial ecosystem respiration. Additionally, the weakened terrestrial carbon sequestration capacity is mainly driven by the transition from temperature or soil moisture control to vapour pressure deficit control, which is associated with the increasing intensity of warm extremes. Our findings suggest that warm extremes threaten the global carbon sequestration function of terrestrial ecosystems. Therefore, more attention should be given to the evolution of the increasing intensity of warm extremes in future climate projections.

Machine learning-based optimal temperature management model for safety and quality control of perishable food supply chain

The management of a food supply chain is difficult and complex because of the product's short shelf-life, time-sensitivity, and perishable nature which must be carefully considered to minimize food waste. Temperature-controlled perishable food supply chain provides the highly crucial facilities necessary to maintain the quality and safety of the product. The storage temperature is the most vital factor in maintaining both the quality and shelf-life of a perishable food. Adequate storage temperature control ensures that perishable foods are transported to the end-users in good quality and safe to consume. This paper presents perishable food storage temperature control through mathematical optimal control model where the storage temperature is regarded as the control variable and the deterioration of the perishable food’s quality follows the first-order reaction. The optimal storage temperature for a single perishable food is determined by applying the Pontryagin's maximum principle to solve the optimal control model problem. For multi-temperature commodities supply chain, an unsupervised machine learning (ML) method, called k-means clustering technique is used to determine the temperature clusters for a range of perishables. Based on descriptive analysis, it is observed that the k-means clustering technique is effective in identifying the best suitable storage temperature clusters for quality control of multi-commodity supply chain.

Autonomous Vibrationless Temperature-Controlled Cryosystem for Optical Studies with a Spectroscopic Ellipsometer

Introduction. Ellipsometry is a highly sensitive, non-destructive optical method used to study the optical and structural properties of materials and thin films.Problem Statement. At the Institute of Semiconductor Physics of the National Academy of Sciences of Ukraine, the first in Ukraine serial spectroscopic ellipsometer SE-2000 (manufactured by SEMILAB Ltd., Hungary) has been employed for research, but its measurement capabilities are currently limited to room temperature.Purpose. This research aims to expand the functionality of the SE-2000 by creating a temperature-controlled cryosystem that operates within a temperature range from –195 оC to +80 оC (approximately 80—353 K).Materials and Methods. An autonomous, precision, vibrationless, cryosystem has been designed and manufactured for low-temperature optical investigations in reflection mode, based on a gas-flow cryostat. The cryosystem includes a cryostat, a microprocessor temperature controller, and an adjustment table.Results. The cryostat operates on a gas-flow principle. A laminar gas flow is generated by excess pressure achieved through the heating of cryogenic liquid by a heater-evaporator in the feeder tank. The flow intensity is regulated by adjusting the power supplied to the heating element, eliminating vibrations in the cryostat and sample. The heat exchange chamber is positioned at the top of the nitrogen tank, with the test sample mounted in horizontal plane. Incident and reflected light beams interact with the sample from the upper hemisphere. Sample positioning is adjustable via translational motion along three Cartesian coordinates and by tilting the cryostat with the help of the adjustment table.Conclusions. This system is suitable for use in optical devices that operate in specular reflection mode, with access to the sample surface from the upper hemisphere.

A control-oriented comprehensive model of PEM electrolyzer considering double-layer capacitance

The modeling of electrochemical and thermal characteristics of proton exchange membrane (PEM) electrolyzer is significant in the hydrogen production process. However, the calculation of electrode impedance and double-layer capacitance during operation is not accurate enough currently, and the electrothermal coupling characteristics of hydrogen production devices are not fully considered. In this paper, the multi-stage equivalent circuit of the PEM electrolyzer is designed using electrochemical impedance spectroscopy (EIS) and the time-constant fitting method. In addition, according to the temperature control system of the actual hydrogen production device, the electro-thermal model of the PEM electrolyzer is established, in which the fuzzy PID control is used to maintain the temperature stability. Moreover, the electrical characteristics and temperature characteristics are simulated in different time scales. Finally, compared to the existing models, the proposed model is more accurate, and it indicates that the proposed model has better accuracy against the existing models.

Electrically Controlled Smart Window for Seasonally Adaptive Thermal Management in Buildings.

Smart windows offer a sustainable solution for energy-efficient buildings by adapting to various weather conditions. However, the challenge lies in achieving precise control over specific sunlight bands to effectively respond to complex weather changes and individual needs. Herein, a novel electrochromic smart window fabricated by integrating a self-assembled cellulose nanocrystals (CNCs) layer with an electrochromic poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS) layer is reported, which exhibits high near-infrared transmittance, low solar reflectivity (26%), and infrared emissivity (20%) in winter, and low near-infrared transmittance, high solar reflectivity (91%), and infrared emissivity (≈94%) in summer. Interestingly, the material offers dynamic temperature control based on its photothermal properties, maintaining the internal temperature of buildings within a comfortable range of 20-25 °C from morning to night, particularly in winter with significant daily temperature fluctuations. Simulations show that the CNC-PED device demonstrates excellent energy-saving and CO2 emission reduction capacities across various global climate zones. This study presents a feasible pathway for constructing season-adaptive smart windows, making them suitable for energy-efficient buildings.

Wavelength Stabilization of Entangled Biphotons Using Dynamic Temperature Compensation for Quantum Interference Applications

AbstractIn this paper, a dynamic temperature compensation method is presented to stabilize the wavelength of the entangled biphoton source, which is generated on spontaneous parametric down‐conversion from a magnesium oxide doped periodically poled lithium niobate waveguide. Utilizing the dispersive Fourier transformation technique, the photon wavelength variation is monitored in case of conventional static temperature control, revealing a long‐term wavelength drift up to 556.8 pm over a 14‐h measurement period. A Hong‐Ou‐Mandel (HOM) interferometer is constructed to assess the impact on quantum applications, showing a decrease in visibility from 95.5% to 69.4%. To address this issue, a digital proportional‐integral‐differential algorithm is implemented to dynamically compensate the working temperature variation of the waveguide, thereby instantly stabilizing the wavelength to a peak‐to‐peak fluctuation of +138.05 pm/‐127.61 pm with the standard deviation being 30.49 pm. The wavelength stability shows more than a hundredfold enhancement in terms of Allan deviation, reaching at an averaging time of 10000 s. With the dynamic control in operation, the HOM interference visibility turns to stable at 96.1% ± 0.6%. The method provides a simple and accessible solution for precisely controlling and stabilizing the wavelength of entangled biphotons, thus improving performance in various quantum information processing applications.

Temperature management of liquid-cooled fuel cells based on active disturbance rejection control

In the proton exchange membrane fuel cell (PEMFC) systems, the operating temperature affects the gas transport, reaction rate and water balance inside the PEMFC stack, thus affecting the output performance and lifetime of the stack. Therefore, it is necessary to study the thermal management methods and control strategies to maintain the stack temperature at the expected value. A thermal management system model of the PEMFC based on the electrochemical reaction and thermodynamics is established. This study proposes a novel active disturbance rejection controller (ADRC) to solve the problem of excessive temperature fluctuation of liquid-cooled stack with the dynamic load current changes. The simulation data show that compared with the PID, Fuzzy-PID and PSO-PID controllers for the cooling fan, the overshoot amount of the coolant inlet temperature with the ADRC is significantly reduced from 1.02 %, 0.77 % and 0.26 % to 0.07 %, and the integral of time absolute error (ITAE) is decreased from 5.299 × 104, 5.206 × 104 and 1.255 × 104 to 3.930 × 103, respectively. The degree of temperature fluctuation is reduced and the parasitic power does not significantly increase. Therefore, the ADRC proposed in this study improves the temperature control effect of the PEMFC stack, which is conducive to enhancing the stack performance.