Calculation of a Potstill + Thumper Distillation Run
An assumption made is that both the pot and thumper have about 13% heat losses. This is fairly common to all stills ...
If you don't know your Pot power input (say you are using gas heating), adjust the Heat-up watts until the "Time to Heat up Pot contents" is close to your data. The Pot power watts can also be determined by matching the calculated results to the Thumper distillate ml/min data or to the final Pot volume.
Timestep minutes are calculated by the program when set to 0. You can input the timestep minutes in the range of 3 to 25 minutes. If you see that a longer run time is needed, use the end conditions of the first run as the input to a new run case. Timestep minutes are adjusted to prevent the pot from emptying.
Passive internal reflux in both vessels is included in the calculations. The calculations are based on comparing the thumper vapor %ABV and amount made results with real run data as described in the thread "Hail the Mighty Thumper".
The pot riser reflux option is an estimate of reflux effects in long cooled pot risers. A maximum value of 36% pot riser reflux gives about 0.4 additional trays at 15% ABV charge and 0.8 additional trays at 40% ABV charge. This greatly reduces the pot and thumper vapor output, so the run time is longer and the pot wattage might need to be increased.
The thumper internal reflux option includes both the vessel and the riser. Values of -30% to +30% of the heat loss for passive reflux can be used. This will add to the heat losses. The thumper vapor ABV and flow rate are determined significantly by the heat losses. The thumper open area above the liquid also affects the heat losses. So, to modify the calculated vapor ABV and flow rate, you can change the internal reflux of the thumper. More thumper internal reflux will give higher heat losses and higher vapor ABV and lower vapor/product rates.
The initial temperature of the thumper is important. It is used in the calculation of the thumper liquid % ABV ( and therefore the vapor %ABV ) when the thumper starts boiling. Ambient temperature base is 30 C, this was used for run data fitting. Changes in the ambient temperature can be used to change the thumper heat loss and vapor ABV.
Time starts when the pot starts boiling vapor over to the thumper. The first two steps are when the thumper is heating up. After that, the thumper is boiling vapor over to the condenser. A different pot power for the start of the run can be specified together with its end time.
The amount of heads is estimated, and the end of the hearts is at 40% thumper vapor ABV. Tails are made from 40% thumper vapor ABV down to the end of the run. Change time step minutes so the run ends at about 20% thumper vapor ABV. These are guidelines for beginners, you should decide when to make cuts based on your taste and smell.
This is Update A. It includes options for using gal or liters and C or F in the Input Data and Results. It also gives a better calculation when a high % of Pot Riser Added Reflux or Thumper Internal Added Reflux are input. The base Thumper Heat Loss is 20% lower in the Update, a better initial value. You can adjust the Thumper Internal Added Reflux to find a Thumper Heat Loss which best matches your product abv % and flow rate data. Results are close to the original version at the same Thumper Heat Loss.