Likely. I'd love to hear an explanation.
BTW, the evaporation experiment is going VERY slowly. I'm logging weights of the 3 mixtures, will graph tomorrow and upload for laughs.
For those of you looking at this thread for tips on cleaning your plate chiller, skip this post.
OK. Let's see if I can jog my memory, back to the dark ages of ChE 101, and come up with a reasonable explanation. Please forgive me if I make some of this too simplistic. I'm not sure what your background is....
When you mix alcohol and water they behave as a single new component. This mixture will have a single boiling point, a single vapor pressure, a single viscosity. Physical properties will only have one value, which is usually some summation of the properties on the individual components. The vapor pressure is what determines how quickly the mixture will evaporate.
Because of the polarity of the mixture, water and alcohol like to stick together. When this mixture is allowed to evaporate, it will do so as a single new component, without either one being preferentially left behind.
Now let's consider a trayed distillation column, like you'd find in a refinery. If you take a single tray from that column and examine it in isolation, and then just look at the liquid phase on that specific tray, you will see evaporation happening. The big difference is that distillation involves contact between countercurrently flowing liquid and vapor phases. The liquid is falling down the column, vapor is flowing up.
Distillation uses evaporation to accomplish separation of components, but often times it takes many theoretical equilibrium stages (areas in the distillation process where the vapor and liquid have the same composition) to accomplish this. You can think of distillation as multiple stages of evaporation and condensation. But, as you go up or down the distillation column, the concentration of the components will vary. Heavier components will be more prevalent in the bottom of the column, and consequently the column will be hotter and usually have a reboiler. This is the stripping section. Lighter components will be at the top and a condenser will be used to send reflux back to the column. This is the rectifying section.
I hope this helps explain my theory of using rubbing alcohol in these plate chillers. The one caveat that might keep this idea from working is if the internal passages are so small as to prevent good mixing of the water and alcohol. If they don't mix well then all bets are off.