Personal climate zone

Some ideas of how to control the temperature inside a drysuit

by Edvin Mellergård, Veronika Aspwall, Martin Koivisto, Malin Björkman

Subject Personal safety
Status Finished
Owner Type Students


When rescue workers are out on a small or medium sized boat it’s favorable if the deck personnel is dressed in dry suits at all time. Both for their own safety should they fall into the water but also in case the rescue suddenly takes a wrong turn and one of the victims fall into the water and needs help to get up.

The rescuers then have to dress accordingly to the water temperature under the dry suit which means that they’ll have to wear thick under garments. Especially during the spring and summer it can get really warm inside the suit which could lead to decreased work capability, increased chance of sea sickness or worse, heat fatigue or a full collapse.


We don’t have a single proposed solution, rather we choose to present several of the best concepts that we have came up with during our the project.

They are all fairly simple and can be used with none or just smaller modifications of the standard equipment used today.

Cooling pad:
This concept consists of a pad with built-in exchangeable freezer packs. The idea is to place the pad in between the drysuit and the undergarments. A belt is then tightened around the drysuit, to press the pad closer to the body and thus provide more efficient cooling. It would provide good cooling, but only for a limited period of time before the freezer packs needs replacement.

Water cooled vest:
The idea with this concept is to use a tight water-cooled vest in between the dry suit and the undergarments. There is a thin plastic tube integrated throughout the vest, and the two tube ends are equipped with nozzles and check valves. The nozzles are connected to a pump apparatus, which is attached to a belt tightened around the dry suit.

The pump apparatus consists of a water pump, a water container and a 12-volt battery with a switch to control the flow rate. The amount of cooling to the vest is thus regulated by the flow rate switch and by the temperature of the water poured into the water container. A water-proof nozzle needs to be attached to the dry suit to ensure a solid connection between the vest and the pump apparatus, and to prevent water from leaking into it.

This also enables the pump apparatus to be removed quickly or even submerged into water if needed. If the dry suit modification haven’t been made, the product can still be used until the user has to dive into the water, by temporarily opening the zipper to connect the vest to the pump apparatus.

The cooling vest is designed not to decrease the user’s mobility. It could also be used on the RescueRunner.

Cooling pillow:
During the prestudy we’ve learned that there are certain areas of the body that are particularly efficient to cool. Not only to efficiently lower the body temperature but also to create a good cooling sensation. We’ve therefore developed a concept that’s focusing on cooling just a few these areas, such as the kidneys, the neck and the shoulders. Some benefits to the product is that it’s small, portable and easy to use. A problem is that it might not cool the user long enough.


During the project we looked at existing market solutions and techniques, not only among sea rescue but also how scuba divers, soldiers, firefighters, combat pilots and medical personel managed to keep cool in warmer climate.

We didn’t find any specialized solutions for sea rescue but especially for medical personell there’s a couple of existing solutions that could easily be adapted for use aboard a boat but many of the solutions require same amount of redesigning to work in the harsh(wet, salty, windy) environment aboard a rescue boat.

Who is behind the project?

We who worked with this project is Edvin Mellergård, Veronika Asplund, Malin Björkman and Martin Koivisto. We’re a bunch of design students at Chalmers University in Gothenburg, Sweden. As the last project during our first year, our class worked together with Svenska Sjöräddningssällskapet,(Swedish Sea Rescue Society) to find a solution to some of their everyday problems. In our group, we choose to work with the problem of freezing and overheating inside a drysuit.


If you have any questions about this project, you can send the project owner a message from here.


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