You ever have an idea that you lack the expertise, funding, ambition, tooling, material and cohesive understanding of scientific principle? So you decide to post it here with hope that when someone else comes out with the idea you can show friends or maybe even lawyers you had the idea first? Just me, okay.

Long bicycle rides cause water in water bottles to warm. I prefer my water on the verge of freezing. My cycling route offers no convenient stores on the way. What am I to do? (4th wall down for a moment, I am "spinning" indoors at the moment to practice responsibility) My front bicycle wheel would have a large center hub similar to a hub motor. Inside would be a piston and evaporator connected to the frame. To this the front brake lever is attached. When you use the front brake you clutch on the piston which forces refrigerant through a circuit. The condenser is made up of modified hollow spokes. As these these are already cooling based on airflow I assume these would work well to dump heat. The kenitic energy of mass is dumped into the refrigeration piston when the rider operates the front brake handle. Cooled metal water bottle holder located near the base of the front forks.
-- evilpenguin, Apr 13 2020

VéloSoleX https://en.wikipedi...wiki/V%C3%A9loSoleX
Invented by someone french, hence cheap and nasty. [8th of 7, Apr 14 2020]

How long are your bike trips? You can get a double wall vacuum insulated water bottle that will fit in a standard bottle cage. Fill it with ice cubes and top up with water. It should last for a good few hours //on the verge of freezing//.
-- pocmloc, Apr 14 2020


Trading momentum for cooling "work" rather than dissipating it as heat is elegant, so [+].

Putting the system in the hub is, however, less elegant. It complicates the linkage to the rest of the system.

Better to have the compressor "drop down" onto the back wheel, using a friction roller - a self-contained unit similar to a VeloSoleX <link> - it could be mounted over the front forks, too, but that affects the handling more.

This could be removed from the bike when not required.
-- 8th of 7, Apr 14 2020


Alternately, the power source could be a propeller mounted in the slipstream (but not on a hat worn by the operator).
-- whatrock, Apr 14 2020


Windmills are unsurprisingly inefficient at such scales. Direct mechanical coupling is much better.

It's perfectly possible to calculate the recoverable energy, given a bike-rider combo of average mass and power output and an approximation of average terrain requiring braking. On flat or nearly flat ground, with few obstacles such as junctions (with or without traffic lights) the rider will have to accept the load of the cooling system as a "penalty". In a situation where braking is obligatory (hilly terrain) then the penalty is limited to transporting the additional mass of the cooling system, the mass of water being a given in any situation.

<later>

This can be effectively prototyped by attaching a single-can cooler to the output of a hub dynamo; but of course that would be silly.
-- 8th of 7, Apr 14 2020



random, halfbakery