Liquid cooling is an excellent choice for resilient marine power systems

When we talk about building more resilient ships, the conversation usually revolves around fuel flexibility, smart energy management and robust control systems. But another layer of resilience at the very core of onboard power conversion often gets overlooked — effective thermal design.

Modern vessels — whether hybrid, fully electric or simply optimized for greater efficiency — rely increasingly on high-performance power electronics. Converters, inverters and drives are doing the heavy lifting behind propulsion, shaft generation and auxiliary power. But these systems are only as reliable as their weakest thermal link. In space-tight, demanding marine environments, heat is not a background issue — it’s a frontline challenge.

Thermal stress – the most underestimated risk

As power density increases and machinery rooms shrink, components are operating under tighter thermal margins. This isn’t just at peak loads. Continuous thermal cycling, hot spots at the semiconductor level and the long-term wear that invisible heat fluctuations impose on sensitive electronics all contribute to thermal stress.

Thermal stress can degrade insulation, shift operating points and lead to early component failure — even in systems that are technically “within spec.” In marine applications where access is limited, uptime is key and repair costs high, avoiding these silent weaknesses is critical to ensuring long-term system integrity.

Electrical systems continue to grow in complexity as the industry moves toward multi-source energy systems using batteries, fuel cells, shore connections and alternative fuels. The reliability of these systems depends on components that can operate consistently over long periods without derating or thermal fatigue.

Resilient power electronics start with optimal thermal design

Good thermal design is foundational, not just an add-on. It supports smarter redundancy strategies, lowers lifecycle costs and makes power conversion systems more resilient to operational variations.

Both air-cooled and liquid-cooled systems can be used. However, air-cooled systems are bulky, need additional space for air circulation and are vulnerable to salt, dust and high humidity.

For marine and offshore applications where efficiency, space, noise and environmental resistance are critical, liquid-cooled drives are often the superior choice despite their added complexity.

The benefits of liquid-cooling systems include:

• Superior cooling efficiency due to direct heat removal
• Small footprint and fewer components    
• Simpler maintenance
• Excellent high-power load handling with reduced thermal losses for improved overall energy performance
• Rapid and precise temperature adjustments
• Reliability in harsh environments
• Focus on the important part – the temperature of the semiconductors

Liquid cooling lowers temperatures where it matters most

At The Switch, our power modules for marine drives are designed with liquid cooling that begins right where the heat is generated — at the semiconductor chip.

Our approach removes heat at the source rather than simply cooling the enclosure or the baseplate around the electronics. The result is efficient and immediate thermal transfer because the coolant flows in close proximity to the power semiconductor substrates. This reduces the operational temperature rise and tightly controls thermal cycling.

Minimizing temperature fluctuations and reducing overall heat accumulation keep the sensitive components inside consistently operating well within their design limits.

The result? Long-term system stability.

Compact, quiet and reliable under marine conditions

This “chip-level cooling strategy” doesn’t just make the system more robust, however. It allows the entire drive and power conversion unit to be smaller, quieter, cleaner and more efficient. And by eliminating the need for large air ducts or forced ventilation, we reduce the risk of contamination from salt, dust or engine room debris. This makes the system well suited to harsh marine environments where reliability matters most.

And because the cooling circuit is highly efficient, it permits greater power density within a smaller footprint — critical in ships where space is always at a premium.

Resilience must be built in, not assumed

In marine electrification, it is easy to focus only on the visible architecture: the drive cabinet, the user interface, the system topology.

But underneath all that are thermal realities — and how well they are planned for will determine how a vessel performs 5, 10 or 20 years from now. Prioritizing thermal management from the chip outward keeps marine power systems cool, consistent and capable.

More than 1,500 The Switch marine drives with liquid cooling are in operation all over the world today. They testify to what we’ve been doing successfully for more than 20 years: cooling marine power systems in an overheated world.