For freezing climates, a sleeping bag that retains heat

With the goal of increased comfort for geologist colleagues who traveled to the harsh Himalayas, Brian Davies developed an innovative sleeping bag.

With the goal of increased comfort for geologist colleagues who traveled to the harsh Himalayas, Brian Davies developed an innovative sleeping bag. Davies, a University of Cincinnati professor and head of the Design for Extreme Environments Project, spoke with me recently about the project. Below are excerpts from our interview.

What was the problem you needed to fix?

We were looking for a way design could contribute to science. We had loose affiliations, through the college, with NASA. We were working with some other people in innovative habitats. That sparked a notion of starting from a design perspective that might be a little more user-centric. How could we partner with geology and materials science? The focus of the partnership became both comfort and temperature.

Describe the sleeping bag you developed.

It was more innovation and application than new materials. We looked at a modulating, self-controlling nano-treatment on fabric. That's expensive and longer term. That's moving in parallel. We just looked at an emergency blanket that has a material property for reflecting body heat. There was no way to regulate the heat. It would retain heat, but you'd have no control other than taking it on and off. If we pursued heat retention and heat reflection, we could lose a lot of bulk and some weight.

The outside layer of the sleeping bag collects and retains heat?

It's like a reversible T-shirt. It has a hot side, the foil side. The soft side would be a little less reflective. You get a medium or high setting on the temperature by flipping it inside or out. We're looking at different ways to vent it. The emergency ones on the market are glued or taped on three sides. We've looked at ways to passively vent it. One of the problems is it getting too hot.

Is it designed specifically for the conditions in the Himalayas, or could it be used elsewhere or in other applications?

Ideally, it would be transferable later. We'll probably only work at a cold temperature. We're looking at temperatures around freezing. Knowing we're at that altitude and that location, we're guaranteed a cold temperature. It might be transferable later to use the reflective material at 60 percent of the surface area. Another thing we're looking at is when we retain all this heat and perspiration that it also doesn't get stinky.

The prototype will be tested this month in the Himalayas. What will the testing entail?

It's a field test from a design perspective. How does it work in context and what are we missing? The geology team needs to make notes on their sleeping bags. Should it actually be a sleeping bag with sleeves? Are their torsos too chilly outside the sleeping bag? If they're trying to write inside the sleeping bag, do the ergonomics work? For the geologists, this is a semi-annual trip. They're doing data collection, measuring erosion, getting data on climate change. We're going along as observers and testers to gain insight into the on-site performance.

What's next for the project?

We'll be tweaking. We'll bring extra materials -- a needle, adhesive, thread -- so we can do field modifications. We're leaving with some completed prototypes, will test and modify them in the field, make our notes, incorporate findings and make adjustments. This is the first round. We can do a few more rounds. Once we have the functioning aspects, we can come back and do the temperature testing here. The evolved sleeping bag would go out with the geology team next year and they would come back with additional feedback.

The long-term goal is to find a partner, either a commercial or scientific partner, that would bring it to production.

Photo: Brian Davies in an early prototype sleeping bag / By Dottie Stover, University of Cincinnati

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