Passive House Isn't Just for Buildings; It Works for Boats Too

The Nanuq, going north in PolarQuest 2018, demonstrates all the virtues of Passive House Design.

TreeHugger recently noted that Fridtjof Nansen was a pioneer of Passive House, the design philosophy that keeps you warm and comfy by using lots of insulation and being really careful about air tightness and ventilation. His boat, the Fram, is considered “the first fully functioning Passive House.”

But it certainly isn't the last boat to be a functioning Passive House. In July 2018 the Nanuq will go on the Polar Quest, "looking for answers to one of the greatest challenges of our time, climate change, and raise awareness about its consequences." They are going to study cosmic rays, assess polar microplastics and nano plastics and, on the 90th birthday of its loss, look for the remains of Umberto Nobile's lost dirigible, the Airship Italia, "taking advantage of the melting ice in the region for the first time in centuries." Nansen's protege (and my hero), Roald Amundsen, was lost looking for Nobile; perhaps they will find his plane too.

But the story here is about the Nanuq, which they describe as a "passive igloo."

Nanuq (meaning polar bear in the Inuit language) is a 60-foot Grand Integral sailboat designed, built and skipped by Genevese architect Peter Gallinelli to sail in the polar region and withstand arctic winter in a self-sufficient mode, using only renewable energies (sun, wind, environmental heat), thanks to its innovative thermal insulation and heat recovery systems, coupled with an optimized energy management system.

© Igloo Sailworks

The big virtue of Passive House is that it's simple. It doesn't require lots of technology, just lots of insulation. The Passive Igloo is insulated to Passive House standards with 8 inches of foam insulation, getting to U=0.12, which I calculate as being equivalent to an American R=45.

© Igloo Sailworks/ EPS foam

That's a bit better than the Fram, and thinner too because the foam is a better insulator than Nansen's cork. It is also structural, the filling between two fiberglass skins, which then all sits inside an aluminum hull. The Fram had 28 inches of wood as its structure, but was designed to resist ice pressure. Nanuq is designed to be pushed up on top of the ice.

© Igloo Sailworks

Only three to six crew stay in the boat all winter, so they live in a small section of the boat that is kept at comfortable temperatures, probably as much by body heat as anything else. But they need fresh air, which is pre-warmed by sea water and then put through a heat recovery ventilator.

© Igloo Sailworks

The ventilation system has been set to recover sensible and latent heat by condensation. The ventilation rate was regulated depending on relative humidity of the air inside the cabin with a minimum ventilation below 50% and maximum ventilation above 80% relative humidity, rarely reached (only when cooking food or on wake up in the morning).

Electricity is a problem; there is no sun and not much wind in an arctic winter. So while they have two wind turbines, in the 2015-2016 winter they ran the boat engine for 45 minutes a day. As they note, it is "a point to improve." Once the sun returned, the 4 solar panels covered all their needs, including running an induction hot plate for cooking.

© Igloo Sailworks/ interior

There is much more that can be found at Igloo Sailworks. In the end, the Nanuq is a microcosm of everything we talk about on TreeHugger: use less of everything, keep it simple. This is the beauty of Passive House, of radical efficiency. Gallinelli explains in a way that applies equally to boats and buildings:

Of all the systems, thermal insulation was the most fundamental prerequisite for the project's success. It is an unspectacular system but the only one that has worked without intervention, without noise, and most of the time without even thinking about it.

That's the definition of Passive House: unspectacular but effective.

The Red Tent/Promo image

And if you want to learn more about the events of 90 years ago, watch Peter Finch as General Nobili and Sean Connery as Amundsen in a crazy muddle of a movie, the Red Tent.