The Bicycle Jersey Problem
The Bicycle Jersey Problem
(OP)
My hobby and sport is bicycling. I recently ran across a discussion of bicycle clothing that presented an interesting problem. If any of you are in academia, this might be a good lab project for someone.
The issue was whether you can actually stay cooler in hot weather with an additional layer of fabric- a base layer. Evidently, cycling clothes are sold for this purpose. The idea is this: If you sweat on bare skin, the sweat is in droplets, not a film. You can put a layer of wicking fabric over the skin, spread the sweat out, evaporate more of it, and actually keep cooler. So we kicked it back and forth in the cycling forum with no definitive answer. What do you all think? Smart idea or snake oil?
(For what it's worth, the proponents of this idea claimed it worked better in drier climates than in humid.)
The issue was whether you can actually stay cooler in hot weather with an additional layer of fabric- a base layer. Evidently, cycling clothes are sold for this purpose. The idea is this: If you sweat on bare skin, the sweat is in droplets, not a film. You can put a layer of wicking fabric over the skin, spread the sweat out, evaporate more of it, and actually keep cooler. So we kicked it back and forth in the cycling forum with no definitive answer. What do you all think? Smart idea or snake oil?
(For what it's worth, the proponents of this idea claimed it worked better in drier climates than in humid.)





RE: The Bicycle Jersey Problem
RE: The Bicycle Jersey Problem
Anyone who has travelled to North Africa and probably Asia use that principle instead of refrigeration to keep water cooler than ambient temperature.
This is the way that I observed it. Water is stored in a leather pouch. This water will ooze out of the leather after a period of time. The leather pouch with water is mounted on the front bumper of a vehicle or some other means of transportation. As the oozing water evaporates, it will absorbe heat from the stored water and reduce the bulk water temperature. The speed of the transportation accelerates the evaporation.
The evaporative cooling works relatively well in dry climates but if the relative humidity is high, evaporation will be much slower which in turn will not effectively cool the bulk of the water stored in the pouch.
RE: The Bicycle Jersey Problem
The theory that a fabric like polypropylene that wicks moisture in one direction will take big drops of sweat and disperse it throughout the fabric is sound--the drops of sweat are large enough to evaporate via a surface function, the dispersed moisture is small enough to be a body function. This is probably important, but I would be surprised if it is the biggest benefit.
Sweat contains considerable dissolved solids. If it evaporates on your skin those solids will stay on your skin and form an insulating layer that inhibits perspiration and reduces heat transfer rate. If the sweat evaporates in the fabric then that effect is delayed a considerable time. I would expect that if you could quantify the two effects, the solids removal would be bigger, but I'm not sure.
David
RE: The Bicycle Jersey Problem
RE: The Bicycle Jersey Problem
RE: The Bicycle Jersey Problem
RE: The Bicycle Jersey Problem
The intriguing thing about the jersey problem is the concept of adding a layer of insulation to keep cool when it's hot, which just seems wrong.
RE: The Bicycle Jersey Problem