Designing the ultimate heated undersuit

[RedSeaDiver2]

Being the sort of person who never believes that what is available can't be made better I have decided to launch into getting a new heated undersuit designed and manufactured.

Part of the reason for this is that I'm not convinced that the current heated undersuits that are on the market are value for money. The most popular ones are obviously the Santi's - the BZ range and the Flex 2.0. - but they don't offer things like built in wiring to connect heated socks etc, and for the price they retail at they damn well should - and if you are in the U.S. then they are about to cost 20% more due to tariffs.

At the moment I am working on a Statement of Requirements - from which the design will be developed - if everyone who is knowledgeable about heated undersuits can chime in with things that they think should be included that would be great - along with anyone else who is interested in potentially getting a heated undersuit - if I can make heated undersuits more affordable for people then I think that is a win for all of us, and it might see a lot more divers diving in the winter months.

So far this is what I have -

• must be more affordable to the end user than what is currently available on the market - at least 20% less $
• heating panels must be individually removable and replaceable
• wiring must be removable and replaceable - for both replacement and washing of the undersuit purposes
• the wiring must include connectors for heated gloves and socks
• a failure of an individual panel during a dive must not prevent the rest of the panels from working
• panels are to have carbon or graphene heating elements
• each panel will have its own individual fuse or similar to protect the wearer in case the panel has a short or similar problem
• the undersuit will have a heated collar - heated collars will be swappable as they will be available in at least two heights as not all of us have a neck like Rachel Maddow
• the undersuit will be available in several different weights/thicknesses of insulation so as users can do things like have a summer and a winter undersuit and just swap the wiring and heating panels between them
• the undersuit will be breathable and will have a waterproof / windproof outershell
• heating panels must be on the torso, thighs, calves and upper and lower arms
• male and female designs - female design will have a drop seat

What else have I forgotten or not thought about? What else would you like to see in the design of a heated undersuit.

 

[Johnoly]

affordable

Since you are in the research phase,,,I just wanted to suggest that "electric" is one possibility. But "water" is another possibility.

Many go-kart & race car drivers use 'Cool-Shirts' that pump tiny bits of temperature controlled water capillaries inside shirts, pants and socks. And astronauts also are using the same devices. This is just an example website, but there are hundreds more.

Motorsports – COOLSHIRT SYSTEMS

coolshirt.com

There are research problems with both Electric and Water systems, but cost advantages with both too.

 

[RedSeaDiver2]

Since you are in the research phase,,,I just wanted to suggest that "electric" is one possibility. But "water" is another possibility.

Many go-kart & race car drivers use 'Cool-Shirts' that pump tiny bits of temperature controlled water capillaries inside shirts, pants and socks. And astronauts also are using the same devices. This is just an example website, but there are hundreds more.

Motorsports – COOLSHIRT SYSTEMS

coolshirt.com

There are research problems with both Electric and Water systems, but cost advantages with both too.

Many years ago there was a Swedish Navy system that used hydrogen peroxide to heat water that was then pumped around under a diver's drysuit.

I think that for the moment I will stick with electric as there is a fair bit of knowledge out there already in its use for our application.

Is anyone particularly knowledgeable about 12V and calculating wire gauge/diameter for given loads etc?

 

[Sascha314]

Make it working effectively, it should be worn underneath main insulation undergarnment. So minimize heat loss to water.
In that way also proper insulation, if the heating fails.
Sonits work as base or midlayer it should habve appropriate sweat / moisture transport.
Should work on various settings from an external tank, so heating power can be adjusted externally.
Some kind of adjustment of relative heat between gloves, socks, legs, arms and torso. Even if its some setting that can only be adjusted predive it would help. Every person is different, and so might be that hands/feet are freezing or torso is too warm and you consume to much energy in that sense.

Not saying its easy but these come to my mind while comparing current options on the market.

 

[ChrisMBC]

- Heating panels on the wrists - I've been experimenting with active heated wrist warmers and I find excellent results with notably warmer hands when I pump 10W of heat into the area just inside my wrists.

- Somewhat watertight connectors, so that they don't get corroded in the case of a suit flood.

I would also challenge the utility of heating panels on the thighs. That's one area that I find stays fairly warm, since those muscle groups are working during the dive.

 

[elvenhome21]

Being that I have direct experience with coolshirts and built my own system for motorcycle application I'll coment on that side.
The only way you could effectively make that work is if you had a heated storage tank pre dive that could bring the liquid to full temp and injected to system right before dive. There's no battery in the world that you'd be able to carry on a dive that can go ambient to warm and then maintain for and hour in a water system. However if you had prewarmed the water you can use the calorie content as a heat sink and only have to add btu to maintain temp which should be a long lasting heat compared to heating pads with no thermal storage. Biggest problem is you need a pump and heater in the loop. This is the one case where I'd be curious if Peltier coolers could possibly be considered more efficient then strictly resistive depending on water temp your diving in. Convective they are horribly in efficient but full water conduction on both sides with temp throttling could be a use case

 

[sinidive]

Is anyone particularly knowledgeable about 12V and calculating wire gauge/diameter for given loads etc?

What you are looking is a wire gauge allowable amperage chart.

e.g. American wire gauge - Wikipedia

 

[grantmac]

SFTech already does this:

Heating Pads - SFTECH

The SF Tech heating system is based on a modular principle that makes it easy to remove or replace heating elements.

www.sftech.ch

 

[elvenhome21]

What you are looking is a wire gauge allowable amperage chart.

e.g. American wire gauge - Wikipedia

Not the right standard for this application.

What you are looking is a wire gauge allowable amperage chart.

e.g. American wire gauge - Wikipedia

In reality 18ga thhn wire should be way more than adequate for any heating system off a dive battery. The standard ampacity rating is meant for conductors behind a wall that can never once be overheated thru use and compromise the insulation. In this application having the wire get warm but not hot is actually a benefit to an extent. Resistance goes up as it gets hot so self throttles to an extent.

 

[RedSeaDiver2]

Make it working effectively, it should be worn underneath main insulation undergarnment. So minimize heat loss to water.
In that way also proper insulation, if the heating fails.
Sonits work as base or midlayer it should habve appropriate sweat / moisture transport.
Should work on various settings from an external tank, so heating power can be adjusted externally.
Some kind of adjustment of relative heat between gloves, socks, legs, arms and torso. Even if its some setting that can only be adjusted predive it would help. Every person is different, and so might be that hands/feet are freezing or torso is too warm and you consume to much energy in that sense.

Not saying its easy but these come to my mind while comparing current options on the market.

Make it working effectively, it should be worn underneath main insulation undergarnment. So minimize heat loss to water.
In that way also proper insulation, if the heating fails.

I'm kind of thinking similar but with a different way of achieving it -

I want the undersuit to have the heated panels so as people are free to choose their own wicking base layer as many people have different experiences and thoughts about these, but the heated panels will be fitted to the inside of the undersuit which should achieve much the same thing.

Should work on various settings from an external tank, so heating power can be adjusted externally.

Totally agree. After an enormous amount of searching I have finally found an external battery that has all of the features that I want - it has four heat settings, and its battery is modular so that it can be taken on a passenger aircraft. It was pure luck that I found it - I stumbled on the brand after a search for something completely different took me to an online dive store in of all places Korea, and there I stumbled across a brand that I had never heard of before and did a google search on them and found the absolute perfect product for this.

Some kind of adjustment of relative heat between gloves, socks, legs, arms and torso. Even if its some setting that can only be adjusted predive it would help. Every person is different, and so might be that hands/feet are freezing or torso is too warm and you consume to much energy in that sense.

I think that I have an idea on how to achieve this, but I won't know until I try it.

Given that the brain reduces heating to the extremities first when the body gets cold, I also want to find a way to perhaps have low heat to these areas without turning on the heating to the rest of the body. I suffer from poor circulation to the feet so this would be a huge help to me. It may be that we offer a customisation option where there are two circuits operated from two separate controls on the same battery, and when someone is purchasing a suit they can select (based on their own knowledge of which areas of their body get more cold or cold more quickly) which areas of the suit are on circuit A and the remainder are on circuit B, and then they can turn circuit A on earlier in the dive, and circuit B during their deco.

Not saying its easy but these come to my mind while comparing current options on the market.

I'm happy to take on the challenge as it not only benefits me but benefits us all.