A durable rubber line comes out of the Hot Water Sleeping Bag (see link) and leads to the campfire, where it changes into a small metal boiler that is placed into the embers of the campfire with a return line (at the top of the boiler) that turns back into tubing that leads back into the bag. Tubing lengths and boiler specs can be tweaked to ensure a steady state at practically any desired temperature whilst sleeping anywhere within, say, 30 feet of an active campfire.
-- daseva, Mar 08 2010

Hot Water Sleeping Bag Hot_20Water_20Sleeping_20Bag
by [treetop]. [daseva, Mar 08 2010]

So, pretty similar to the technology pictured in my link to the original Hot Water Sleeping Bag idea?
-- jurist, Mar 08 2010


[-] For less weight, bulk and cost, you could simply get a thicker sleeping bag which would keep you however warm as you wanted to be... and without the risk of getting scalded.
-- goldbb, Mar 08 2010


It's stupidly impractical, and therefore perfectly halfbaked. I like it a lot +
-- xenzag, Mar 08 2010


[marked-for-deletion] it's a copy of the other one, come on.
-- FlyingToaster, Mar 08 2010


It's different. The other one is no good, but this one is ok.
-- xenzag, Mar 08 2010


Far from it, flyingtoaster. The other one has no continuous-flow heat engine.

[jurist], yes the technology is virtually the same. However, in the hot tub version, the methods of control lie in the heat of the fire, only. There is no closed heating fluid, essentially, since the hot tub water *is* the fluid.

In this device, you can open and close valves between the boiler and the bag to adjust the amount of steam that escapes the boiler and thus control the heat inside your blanket. There could be a release valve to the surroundings right near the bag, too. This would allow for user control next to the bag, and would also steam the tent (or not if you put the sparger outside the tent).
-- daseva, Mar 08 2010


What a good idea ,I never would of it!!!
-- treetop, Mar 11 2010


yeah, something an 11 year old could invent!
-- xandram, Mar 11 2010


Shouldn't this be under product:device:torture and renamed "Waterbedding"?
-- Canuck, Mar 13 2010



random, halfbakery