Reflux Rate for VM

[Centimeter]

Almost done with my VM still. I will post pictures soon. I had a question about calculating the reflux ratio. Here’s my idea.

Measure the temperature of the coolant water both entering and leaving the reflux condenser. Using the specific heat of water and the rate of collection I can calculate the joules involved in reflux condensation. I can then, using the phase change energy of ethanol (assuming pure) coupled with the specific heat of ethanol (assuming pure) calculate the mass of ethanol condensed per unit time. Would the condensed ethanol leave the coil at the temperature of the incoming coolant (I kind of think not… but could be close)?

Would this be a reasonable way to calculate reflux? How are you guys calculating reflux for a VM still? I'm looking for hard calculations not rough estimates of what you'd expect vs what you get.