skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


This content will become publicly available on May 26, 2026

Title: Process monitoring and safety‐informed control of a proton exchange membrane water electrolysis system
Abstract This study provides an experimental validation of a multiple‐input multiple‐output (MIMO) model predictive control (MPC) strategy, coupled with dynamic risk modeling, to address two critical aspects of proton exchange membrane water electrolysis (PEMWE) operation: (i) process safety, by mitigating temperature imbalances, and (ii) system performance, through precise hydrogen production control. A cyber‐physical platform was developed for real‐time monitoring, state‐space modeling and validation, risk metrics analysis, control implementation, and visualization. Open‐loop experiments revealed limitations in managing thermal gradients, underscoring the need for feedback operating strategies. The proposed closed‐loop MPC approach achieved precise tracking of hydrogen production while maintaining safety by ensuring temperature stability. Moreover, the dynamic risk metrics show how thermal risk evolves with temperature and offer guidance for decision‐making. These findings demonstrate the effectiveness of MIMO MPC in enhancing the operational safety and efficiency of PEMWE systems, providing a foundation for scalable and sustainable hydrogen production.  more » « less
Award ID(s):
2312457
PAR ID:
10593135
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
AIChE Journal
ISSN:
0001-1541
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Maintaining operational efficiency while ensuring safety is a longstanding challenge in industrial process control, particularly in high-risk environments. This paper presents a novel Dynamic Risk-Informed Explicit Model Predictive Control (R-eMPC) framework that integrates safety and operational objectives using probabilistic constraints and real-time risk assessments. Unlike traditional approaches, this framework dynamically adjusts safety thresholds based on Bayesian updates, ensuring a balanced trade-off between reliability and efficiency. The validation of this approach is illustrated through a case study on tank level control, a safety-critical process where maintaining the liquid level within predefined safety limits is paramount. The results demonstrate the frameworks capability to optimize performance while maintaining robust safety margins. By emphasizing adaptability and computational efficiency, this research provides a scalable solution for integrating safety into real-time control strategies for similar process systems. 
    more » « less
  2. n this paper, we focus on the problem of shrinking-horizon Model Predictive Control (MPC) in uncertain dynamic environments. We consider controlling a deterministic autonomous system that interacts with uncontrollable stochastic agents during its mission. Employing tools from conformal prediction, existing works derive high-confidence prediction regions for the unknown agent trajectories, and integrate these regions in the design of suitable safety constraints for MPC. Despite guaranteeing probabilistic safety of the closed-loop trajectories, these constraints do not ensure feasibility of the respective MPC schemes for the entire duration of the mission. We propose a shrinking-horizon MPC that guarantees recursive feasibility via a gradual relaxation of the safety constraints as new prediction regions become available online. This relaxation enforces the safety constraints to hold over the least restrictive prediction region from the set of all available prediction regions. In a comparative case study with the state of the art, we empirically show that our approach results in tighter prediction regions and verify recursive feasibility of our MPC scheme. 
    more » « less
  3. Including a multifunctional, bioregenerative algal photobioreactor for simultaneous air revitalization and thermal control may aid in carbon loop closure for long-duration surface habitats. However, using water-based algal media as a cabin heat sink may expose the contained culture to a dynamic, low temperature environment. Including psychrotolerant microalgae, native to these temperature regimes, in the photobioreactor may contribute to system stability. This paper assesses the impact of a cycled temperature environment, reflective of spacecraft thermal loops, to the oxygen provision capability of temperate Chlorella vulgaris and eurythermic Antarctic Chlorophyta. The tested 28-min temperature cycles reflected the internal thermal control loops of the International Space Station ( C . vulgaris , 9–27°C; Chlorophyta-Ant, 4–14°C) and included a constant temperature control (10°C). Both sample types of the cycled temperature condition concluded with increased oxygen production rates ( C . vulgaris ; initial: 0.013 mgO 2 L –1 , final: 3.15 mgO 2 L –1 and Chlorophyta-Ant; initial: 0.653 mgO 2 L –1 , final: 1.03 mgO 2 L –1 ) and culture growth, suggesting environmental acclimation. Antarctic sample conditions exhibited increases or sustainment of oxygen production rates normalized by biomass dry weight, while both C . vulgaris sample conditions decreased oxygen production per biomass. However, even with the temperature-induced reduction, cycled temperature C . vulgaris had a significantly higher normalized oxygen production rate than Antarctic Chlorophyta. Chlorophyll fluorometry measurements showed that the cycled temperature conditions did not overly stress both sample types (F V /F M : 0.6–0.75), but the Antarctic Chlorophyta sample had significantly higher fluorometry readings than its C . vulgaris counterpart ( F = 6.26, P < 0.05). The steady state C . vulgaris condition had significantly lower fluorometry readings than all other conditions (F V /F M : 0.34), suggesting a stressed culture. This study compares the results to similar experiments conducted in steady state or diurnally cycled temperature conditions. Recommendations for surface system implementation are based off the presented results. The preliminary findings imply that both C . vulgaris and Antarctic Chlorophyta can withstand the dynamic temperature environment reflective of a thermal control loop and these data can be used for future design models. 
    more » « less
  4. ABSTRACT In therapeutic focused ultrasound (FUS), such as thermal ablation and hyperthermia, effective acousto‐thermal manipulation requires precise targeting of complex geometries, sound wave propagation through irregular structures, and selective focusing at specific depths. Acoustic holographic lenses (AHLs) provide a distinctive capability to shape acoustic fields into precise, complex, and multifocal FUS‐thermal patterns. Acknowledging the under‐explored potential of AHLs in shaping ultrasound‐induced heating patterns, this study introduces a roadmap for acousto‐thermal modeling in the design of AHLs. Three primary modeling approaches are studied and contrasted using four distinct shape groups for the imposed target field. They include pressure‐based time reversal (TR) (basic (BSC‐TR) and iterative (ITER‐TR)), temperature‐based (inverse heat transfer optimization (IHTO‐TR)), and machine learning (ML)‐based (generative adversarial network (GaN) and GaN with feature (Feat‐GAN)) methods. Novel metrics, including image quality, thermal efficiency, thermal control, and computational time, are introduced, providing each method's strengths and weaknesses. The importance of evaluating target pattern complexity, thermal and pressure requirements, and computational resources is highlighted. As a further step, two case studies: (1) transcranial FUS and (2) liver hyperthermia, demonstrate the practical use of acoustic holography in therapeutic settings. This paper offers a practical reference for selecting modeling approaches based on therapeutic goals and modeling requirements. Alongside established methods like BSC‐TR and ITER‐TR, new techniques IHTO‐TR, GaN, and Feat‐GaN are introduced. BSC‐TR serves as a baseline, while ITER‐TR enables refinement based on target shape characteristics. IHTO‐TR supports thermal control, GaN offers rapid solutions under fixed conditions, and Feat‐GaN provides adaptability across varying application settings. 
    more » « less
  5. Abstract AimUnderstanding and predicting the biological consequences of climate change requires considering the thermal sensitivity of organisms relative to environmental temperatures. One common approach involves ‘thermal safety margins’ (TSMs), which are generally estimated as the temperature differential between the highest temperature an organism can tolerate (critical thermal maximum, CTmax) and the mean or maximum environmental temperature it experiences. Yet, organisms face thermal stress and performance loss at body temperatures below their CTmax,and the steepness of that loss increases with the asymmetry of the thermal performance curve (TPC). LocationGlobal. Time period2015–2019. Major taxa studiedAnts, fish, insects, lizards and phytoplankton. MethodsWe examine variability in TPC asymmetry and the implications for thermal stress for 384 populations from 289 species across taxa and for metrics including ant and lizard locomotion, fish growth, and insect and phytoplankton fitness. ResultsWe find that the thermal optimum (Topt, beyond which performance declines) is more labile than CTmax, inducing interspecific variation in asymmetry. Importantly, the degree of TPC asymmetry increases with Topt. Thus, even though populations with higher Topts in a hot environment might experience above‐optimal body temperatures less often than do populations with lower Topts, they nonetheless experience steeper declines in performance at high body temperatures. Estimates of the annual cumulative decline in performance for temperatures above Toptsuggest that TPC asymmetry alters the onset, rate and severity of performance decrement at high body temperatures. Main conclusionsSpecies with the same TSMs can experience different thermal risk due to differences in TPC asymmetry. Metrics that incorporate additional aspects of TPC shape better capture the thermal risk of climate change than do TSMs. 
    more » « less