Hammock Innovations for a High School Project

I am a senior in high school enrolled in an Engineering Development and Design class and me and my two partners chose to innovate a modern camping hammock to allow for a more integrated insulation design that would allow for lower cost after all the accessories are bought. Our design currently consists of a simple hammock design with an inflatable hammock integrated under the hammock to eliminate the "cold-butt syndrome" that a lot of people would have to get 1 or 2 pads, under quilts, etc. to get rid of it. The inflatable part will just be placed under the hammock to allow for quick and efficient airing up. The increased R-Value will eliminate the need for a extra quilts are pads which will help save money. We are still the developing the idea, so our design is a little unrefined. We are hoping you can help us out by giving us some feedback on the idea. Is it a viable idea? If developed, will it actually help out the community? Is there anything we could do to improve the design? Do you believe that you have a better idea? If you are interested in giving us more data, please visit this survey: https://www.surveymonkey.com/r/BBRQBDS

there's a couple manufacturors that already do this

EDIT:
https://www.cruaoutdoors.com/product...d-hammock-tent

there's a couple others I've seen, but this was the one I remembered off the top of my head

Can you tell us who?

I’m not aware of inflatable insulation as part of the hammock itself. The biggest problem is pads do wear out. Sheltowee and Bonefire Gear both have integrated insulation in Hammocks. Another issue would be different needs for different seasons. I like seperate insulation. It can help when going to ground, is easily changeable, and allows me to get the best hang in my hammock without the restriction of something else trying to force me to lay in a preplanned way. That’s my .02.

My packraft has an integrated inflatable seat to sit on. Works well against the cold water, but if the air is cold so is the air inside and against your butt unfortunately.

Be interested to see what you come up with.
So....kinda like a pad hanging under the hammock?
Get on it!
Shug

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Originally Posted by Jdurh

I am a senior in high school enrolled in an Engineering Development and Design class and me and my two partners chose to innovate a modern camping hammock to allow for a more integrated insulation design that would allow for lower cost after all the accessories are bought. Our design currently consists of a simple hammock design with an inflatable hammock integrated under the hammock to eliminate the "cold-butt syndrome" that a lot of people would have to get 1 or 2 pads, under quilts, etc. to get rid of it. The inflatable part will just be placed under the hammock to allow for quick and efficient airing up. The increased R-Value will eliminate the need for a extra quilts are pads which will help save money. We are still the developing the idea, so our design is a little unrefined. We are hoping you can help us out by giving us some feedback on the idea. Is it a viable idea? If developed, will it actually help out the community? Is there anything we could do to improve the design? Do you believe that you have a better idea? If you are interested in giving us more data, please visit this survey: https://www.surveymonkey.com/r/BBRQBDS

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An interesting project. I filled out your survey and I'll offer a few thoughts below.

- For more research on things tried in the past, like ten years or so ago, look at Just Jeff's page: http://www.tothewoods.net/

- Look at the Amok Dramur hammock which relies on an inflatable pad for structure. Here's Shug's playlist: https://www.youtube.com/playlist?lis...t-nToMYkAsb8HL

- Rather than making the pad an integral part of the hammock, couldn't you achieve the same thing with a double layer hammock that has a pad sleeve between the layers? Plenty of those exist already.

- An inflatable integrated pad for insulation sounds interesting and I'd like to see how it goes, though I'm not interested enough to spend money on it at present. Are you going to rely solely on the dead air space inside the pad for insulation value? That is going to be difficult to achieve with air alone. The warmest pads probably are self inflating, meaning they've got some foam in there too, but you blow them up as well for more cushion. Air alone in any sizeable space will be a poor insulator, mostly because of internal convection currents.

Try lying on one of those inflatable beds that are sold as a space saving temporary guest solution. Those things are COLD! The air in them circulates within the shell and sucks heat out of your body. The same thing will happen in an air mattress lying on the ground, even if only an inch or so thick. If the air can move, it will. The only way to stop it is millions of tiny air spaces like closed cell foam or open cell foam which trap the air and keep it from moving around inside the pad. But if you're going to integrate foam into your pad, then the hammock itself won't fold up very small (though it might roll up like a pad, I suppose).

Good luck and please post the results of your project. You'll get a lot of eyeballs on it and plenty of comments but be prepared for criticism too.

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Originally Posted by sidneyhornblower

- An inflatable integrated pad for insulation sounds interesting and I'd like to see how it goes, though I'm not interested enough to spend money on it at present. Are you going to rely solely on the dead air space inside the pad for insulation value? That is going to be difficult to achieve with air alone. The warmest pads probably are self inflating, meaning they've got some foam in there too, but you blow them up as well for more cushion. .

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Crua Hammocks do it this way I believe

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Originally Posted by sidneyhornblower

- An inflatable integrated pad for insulation sounds interesting and I'd like to see how it goes, though I'm not interested enough to spend money on it at present. Are you going to rely solely on the dead air space inside the pad for insulation value? That is going to be difficult to achieve with air alone. The warmest pads probably are self inflating, meaning they've got some foam in there too, but you blow them up as well for more cushion. Air alone in any sizeable space will be a poor insulator, mostly because of internal convection currents.

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Some of the pads are filled with down which compresses nicely and reduces the internal air currents which makes the pads warmer.

From the description of your project and your explanations I get the impression that you don't have too much experience with hammocks. For example you say that "a lot of people would have to get 1 or 2 pads, under quilts". You might need to use 2 pads in a gathered end hammock because standard ground pads are too narrow to cover the shoulders, but just for insulation purposes, one pad is usually enough. And you would only use 2 underquilts if you didn't want to buy a warmer underquilt (e.g. because you wouldn't use it enough to justify the expenses).

In my opinion, before you can innovate anything, you should have a thorough look at not only what's already available, but at what is considered best by experienced users. Have you tried hammocks and under-insulation made by the best regarded manufacturers? As students, money is probably an issue. But you could always visit a hangout or ask if there are forum members with interesting gear that they would be willing to show near you.

I - as most hammock users - have experimented with pads in hammocks before I bought my first underquilt. And over the years, I have used pads on and off. They are easy to use in that you either lie on the pad or not - but they are not easy to hold in place. Maybe your design would solve this. But the other issue I have with pads is condensation. I don't get much, but I get some - in contrast to an underquilt. I don't see how you could solve that, because it's unfortunately a "feature" that all inflatable or closed-cell pads share. Another thing I didn't like with inflatables is that you have to deflate them and roll them up tightly to be able to get them in your pack - which is hard to do off the ground.

Pricewise are you sure that you could sell a 3-season inflatable hammock for under $200? Because this is about the cost of a simple 11' netless hammock plus full-length 3-season synthetic underquilt. I doubt that you can come up with something that fulfills all your criteria (simple, easy to set up, warm and cheaper than existing solutions), that's why I wouldn't focus on the price. If you can come up with a design that let's you comfortably use inflatable insulation in a gathered end hammock, you'd have an innovation. And if in addition the weight would be comparable to a hammock plus synthetic underquilt AND you could go to ground, you might have a winner - even if it was more expensive.

Wow Jdurth, what a great project and a great opportunity you have at your school to pursue this type of education. I am actually surprised at the initial responses you have received. But they too are a great part of this education process. Any new idea or pursuit will come with plenty of criticism and nay sayers the will try and discourage you. This is already been done, this is not needed, or your crazy and have not clue what your talking about. Let me encourage you to push through all that and persevere. Funny I was just watching a documentary on Frank Whittle just before seeing this post. He had his detractors in spades but still changed the world.

Back to your project, It is intriguing and has merit. There may be some similar ideas out there but none are exactly like you are envisioning. I would engorge you to set out and identify the design space you want to attack. i.e. do not try to make a one-size fits all design. Refine you goals to say design a insulation free hammock to perform in the 65F to 50F or even down to 40F range.

Items that may be a challenge include how to make you air chambers sealed, yet allow them to pack down. (flexibility in the fabric) will continued folding and flexing cause leaks.

The post that dismissed this idea saying air insulation is not viable does not correct but is not 100% wrong. Air makes a great insulation, however, the practical experience expressed highlights another issue you will need to solve. That is how to control convection in the insulation layer.

Let me conclude buy reiterating my encouragement in pursuing this idea. Go for it. make it happen and ignore those that say you can't.

For my colleagues here on this forum, please remember, this is a high school project, where would you be if you had people around you that encouraged you instead of knocking you down. Where would the Tenashedron stand be if we gave leatherdome this kinda of initial feedback a year go.

I truly believe that the problems discussed are not convection at all. Convection within a closed space brings the warmer air to the top, just exactly where you would want it to be! Convection does NOT cause warm air to fall. I believe the physics that apply here is that, without some material in the space that is actually a poor conductor of heat, the bottom of the upper skin radiates heat that is absorbed by the bottom layer and is then, in turn, either radiated once again into the air or conducted on to the next material, that being floor, ground, etc.

Where convection truly become a problem is where the warmest air accumulates at the top of a wall cavity or at the ceiling of a room and then the differential between conditioned and unconditioned space causes faster heat transfer.

It's a complex combination of radiation, conduction, and (to a lesser extent) convection that leads to most heat loss.

Sometimes windchill is equated with convection and they are definitely not the same thing. Wind moves warm air away from, in this discussion, the hammock at a much faster rate than any convection current ever could.

The idea of integrating insulation into the hammock has merit enough to have been done many times. But nobody's yet found the secret of a resoundingly superior way. The fact that light and effective underquilts tend to cost quite a bit more than hammocks themselves is natural given the cost of the known most desirable materials (down) and construction labor, but does lead to a lot of cognitive dissonance among buyers. I think there's definitely opportunity to find some sweet spot of price/performance to grow the market from the middle, rather than from the ends (cheap and heavy/bulky or just not very warm at low end, really expensive and really nice at high). If it was easy, maybe it would already have been done!

As has been mentioned, air that's free to move around in an open chamber isn't that great an insulator. But fill the chamber with something fluffy and packed bulk/weight goes up. If your chambers are airtight, they are also non-breathable, which will lead to condensation problems inside or out as the dew point will turn all that moist breath into a mildew/stink hazard. Also as any air-mattress or pad user knows, one tiny pinprick can ruin your night. In a hammock where comfort doesn't depend on the padding an inflated pad can provide, I don't see much upside to inflation. Add the fact that any inflated non-flexible membrane with some internal pressure has a firm/stiff surface that isn't going to conform to what it's held against. Sort of why you've never heard of an inflatable topquilt: it's not going to seal and eliminate gaps or voids.

Really hard to beat just immobilizing a certain amount of air underneath the hammock in a breathable manner, possibly incorporating a radiant layer as well to minimize the amount of trapped air necessary to perform at a given temp. Down is the gold standard here, but pricey and can't let it get wet. Synthetics can work as well, better in wet conditions, and cheaper but neither as light nor compressible.

Here's a thin down UQ that claims to boost the rating with a breathable radiant layer: https://www.2gosystems.com/collectio...t=501404958729 . I don't know how well it works, but I'm intrigued: what if sewn into a hammock? How much bulk and weight in down or synthetic insulation can be replaced with that radiant layer?

Here's a simple cheap poly-fill quilted hammock I use and like for indoor travel: https://www.lasiesta.com/us/en/colle...nsion-cqh15-49

I don't think much of pads (I get tons of condensation), and I definitely don't think air is much of an insulator, but there are some who do:

https://hammockforums.net/forum/show...ill-for-and-UQ

Or the guy who wanted to use bellybutton lint as insulation:

https://hammockforums.net/forum/show...ent-Insulation

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Originally Posted by SilvrSurfr

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Or the guy who wanted to use bellybutton lint as insulation:

https://hammockforums.net/forum/show...ent-Insulation

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Maybe hummingbird down!

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Originally Posted by TominMN

Sometimes windchill is equated with convection and they are definitely not the same thing. Wind moves warm air away from, in this discussion, the hammock at a much faster rate than any convection current ever could.

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Ah, That is the definition of convection... Heat transfer due to the movement of a fluid. You are describing natural convection and forced convection. Also, it is incorrect to think that air in a closed system is static and there are no currents, as is pointed out on Earth hot air rises, thus as there is a heat source, the person, and a heat sink, the bottom of the pad, there will always be current and convection heat transfer. In this system it is the dominant mode a heat transfer. Wind chill is a human perception of air temperature vs. actual air temperature.

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Originally Posted by jeff-oh

Ah, That is the definition of convection... Heat transfer due to the movement of a fluid. You are describing natural convection and forced convection. Also, it is incorrect to think that air in a closed system is static and there are no currents, as is pointed out on Earth hot air rises, thus as there is a heat source, the person, and a heat sink, the bottom of the pad, there will always be current and convection heat transfer. In this system it is the dominant mode a heat transfer. Wind chill is a human perception of air temperature vs. actual air temperature.

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Yes, of course hot air rises, except under very peculiar circumstances. As does warm water. I suppose that it might be even more accurate to state that warm air is forced up as heavier, cooler air sinks. But the effect is the same. I'd hardly call Earth and the surrounding atmosphere a closed system though!

You are correct. I was only considering natural convection. I've never considered "forced convection" as a truly accurate description of the physics (maybe even an oxymoron), even though the term seems to be in general usage. And convection is heat movement, not transfer, per se; The heat remains in the medium.

I should have typed "wind effect" instead of "wind chill."

And, I wouldn't ever claim that air in a closed system is static. As long as there are molecules present, particularly water vapor, it is going to move around. Still, the warmest air will generally be at the upper portion of the chamber. Convection isn't the vehicle that moves the heat to the next medium.

And FWIW, VERY dry air actually has a relatively high "r" value; it does not conduct heat very well at all. It just doesn't commonly exist.

Heat sinks rely on conduction. That would be heat transfer from the air to the bottom of the pad. Doubt the bottom of the pad has enough mass to hold much heat. Now, if that pad is in contact with the ground, then the two substances combined would constitute a heat sink. Otherwise the heat is radiating and/or conducting to air on the other side at roughly the same rate as it is absorbing from the air inside.

That sounds like a great product you are trying to innovate. I would suggest if you have the gear, to hang and nap, or hang and sleep in a variety of temps and tree set ups. This gear to me sounds like it would work well for car camping, or sleeping outside your house, camp, etc... Hammockers find themselves in a variety of trees, poles, and underbrush when hanging. How would it work if space to hang was close together, or far apart? Diagonal lay or banana lay?
I hope you discover lots of information and have fun with this project. I find that highschool students can be quite innovative, even when the adults around them can be less than supportive, or think they know better so why try your idea. Sometimes the adults are right, but I have been surprised and amazed more often than not when teens are left alone to work out and discover their own methods and ideas.
Good Luck!