Monday, June 27, 2016

The Lasko Vortex Amplifier XE

Most of the e-mail you sent about the Lasko Vortex focused on a fundamental design flaw. James explained it best:
Just a few words on drying in case you need them...

There are two concepts you have to take into account when drying any liquid from any surface or material:

- Partial Pressure
- Vapour pressure

From Wikipedia (since my understanding of the concept is similar but more nuanced):
Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases (i.e., liquid or solid). Most often the term is used to describe a liquid's tendency to evaporate. It is a measure of the tendency of molecules and atoms to escape from a liquid or a solid.

The partial pressure of a gas is a measure of thermodynamic activity of the gas's molecules. Gases dissolve, diffuse, and react according to their partial pressures, and not according to their concentrations in gas mixtures or liquids.

Essentially, what that's saying is that if there's no gas of that liquid in the surrounding atmosphere then the molecules of the liquid will evaporate to reach the equilibrium point.

Think of it this way - all liquids have an 'atmosphere' in the region directly above them (like the Earth). This blanketing layer is the barrier that stops constant evaporation so removing that layer will increase evaporation. There is slower diffusion into the larger area beyond that in a static volume, so this is the rate-limiting step.

There are three things you can do to ensure faster and complete drying:

1) Do not fold or have layers/surfaces in contact with each other as this will keep the liquid atmosphere in place
2) Provide turbulence and ventilate the area, removing (not recycling) the air to reduce the partial pressure of the liquid you're removing
3) Increase the ambient temperature of the area where the items to be dried are as this will push the equilibrium of the vapour-liquid towards the vapour side of the equation

So basically, I needed to separate the clothes and have openings for the humidity to vent or nothing was going to dry.

I did. I opened each end of the closet (standard hotel closet) about 12", put the fan inside, and let it run.

It worked pretty well, actually. Everything dried, and quicker than I expected. If you're having a drying emergency, this is a decent way to dry your clothes.

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