(Invited) Development of Durable and Low Cost Membrane Humidifiers for Fuel Cell Systems
Bibliographic record
Abstract
In order to operate effectively, currently commercialized fuel cell proton exchange membranes require sufficient hydration to ensure good proton transport. Hydration also ensures that membrane in the fuel cell stack will have a longer operational lifetime. In order to ensure adequate hydration in the stack, most liquid-cooled PEM fuel cell systems use external humidification. Without external humidification, the fuel cell must be operated at a lower operating temperature to ensure that the stack will not dry out. Operating the stack at lower temperature requires that the coolant loop in the system must reject a greater amount of heat, necessitating a large radiator, which increase system volume. Furthermore, operating at lower fuel cell stack temperatures leads to a significant trade-off in terms of stack power output and acceptable environmental operating ranges. Membrane humidifiers are an efficient form of external humidification that transport humidity through a membrane from the cathode exhaust to the incoming cathode supply air stream. In these humidifiers, membranes with a dense selective layer are used to transport water vapour without allowing oxygen and nitrogen to diffuse through the membrane. Since the membrane humidifier is coupled to the stack cathode exhaust and supply, in order to maintain its function, the membrane humidifier must not leak air or else reactant oxygen will bypass the stack through the humidifier. The humidifier must maintain a high level of water vapour transport and low air leakage over the lifetime of the device. In this presentation we present our work developing low-cost selective membranes for fuel cell humidification. These membranes are functional over a wide temperature range (-30 to +110°C) and have high water vapour permeance. They are resistant to contamination, relative humidity cycling, freeze-thaw cycling, oxidation, hydrolysis, and acidic conditions that are present in the cathode exhaust. This presentation will also discuss the incorporation of these flat-sheet membranes in to heat and mass exchangers (membrane humidifier cartridges). These cartridges are compact with a high membrane-to-volume ratio, high water vapour transport, and have low pressure loss. The membrane humidifiers are robust to a wide range of operating conditions. Furthermore, the design of these cartridges allows the humidifier to be manufactured at a low cost in high manufacturing volumes. Finally, this presentation will discuss membrane-based heat and mass exchanger performance at different operating conditions. A performance model will be presented which summarizes humidifier performance as a function of membrane properties, exchanger design and architecture, and fuel cell operating conditions.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".