A recent study from Jiangsu University [32.2°N, 119.4°E], in China, tackles a critical challenge in hydrogen fuel technology: keeping hydrogen circulation pumps running smoothly in freezing temperatures. Hydrogen fuel cells, which power vehicles and clean energy systems, rely on these pumps to maintain hydrogen flow. However, in extreme cold, ice can form inside the pumps, slowing down performance or even causing complete failure.
This research offers new insights into how ice melts inside hydrogen circulation pumps, helping engineers design more efficient and reliable fuel cell systems that work even in Arctic-like conditions.
The Challenge: Ice Buildup in Hydrogen Pumps
Hydrogen circulation pumps are a key component in fuel cell vehicles, ensuring that unused hydrogen is recirculated to maximise efficiency. However, in temperatures as low as -30°C, moisture in the system can freeze, forming ice layers on the rotor surface. This leads to:
- Reduced airflow, slowing down pump operation.
- Higher energy consumption, as the system struggles to overcome ice resistance.
- Potential pump failure, risking breakdowns in fuel cell vehicles.
To address this, the study developed a numerical simulation model to analyse exactly how ice melts inside hydrogen pumps under different conditions.
Key Findings: How Ice Melts in Hydrogen Pumps
The researchers simulated the melting process using hot air flow inside the pump and discovered four key patterns that could improve performance:
- Melting is Rapid at First, Then Slows Down
- Initially, when hot air enters the pump, ice melts quickly where the airflow is strongest.
- As the ice layer shrinks, its surface area decreases, leading to a slower melting rate over time.
- Higher Airflow Speeds Up Melting—But Only to a Point
- Increasing the hot air flow rate from 1m/s to 5m/s improved melting efficiency.
- However, beyond a certain speed, the effect plateaued, meaning there’s an optimal airflow rate for defrosting pumps efficiently.
- Larger Ice Layers Take Much Longer to Melt
- The thicker the ice, the longer it takes to melt, but not in a simple linear fashion.
- Heat from the air melts the outermost layers first, meaning that a small increase in ice thickness leads to a much longer defrosting time.
- Temperature Distribution Affects Pump Efficiency
- Ice melting creates temperature differences inside the pump, which in turn affects airflow and heat transfer.
- Over time, as the ice disappears, these temperature differences even out, stabilising pump performance.
What This Means for Hydrogen Technology
These findings have real-world applications for making hydrogen fuel cells more reliable, especially in colder regions:
- Better pump designs → Engineers can optimise airflow and heating strategies to prevent icing before it becomes a problem.
- More efficient vehicle start-up → Fuel cell cars in winter conditions could operate more reliably with preheated air defrosting systems.
- Improved hydrogen storage and transport → The insights could help avoid icing issues in larger-scale hydrogen pipelines and refuelling stations.
As hydrogen energy becomes a mainstream clean fuel, overcoming cold-weather challenges will be key to making fuel cell technology as practical and dependable as petrol or diesel.
Source
Characterisation of Rotor Surface Melt Ice Heat Transfer in Hydrogen Circulation Pumps, SSRN Preprint, 2025-02-15
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