Why Cooling Sometimes Sucks!

Starting a boil in your still results in vapors being produced. That’s how distillation works: you apply heat at one end to create gasses and you apply coolant at the other end to liquify these gasses.

Heating and cooling, and they should work together in perfect harmony. And they do. Well, as far as we design the iStills. Each and every design has a cooler that matches the power input. The cooler on an iStill 500 can cool down 18 kWh, while the iStill 100’s cooler matches its own, smaller, power input.

No worries then? Well, no, if you use water as the coolant of choice, and when you make sure it is below 10 degrees Celsius.

Now, I can hear you think … “What if our water isn’t 10c, but warmer?” And that would be the perfect follow-up question. Many live in warmer climates, where tap water is well above 10 degrees Celsius. And with the warmer cooling water comes a progressive decline of that water’s cooling capacity.

See the problem? In warmer climates, you need a chiller. That chiller is a device that cools the water down to below the required 10 degrees Celsius. The slightly higher electricity bill off-sets the lower water usage easily. Problem solved.

So why cooling sometimes suck? Well, because your distillery is situated in a warm climate. Congrats on the nice weather and our condoleances for having to invest in a chiller. That easy? If only it were … because, wait, there is more!

It turns out that cooling doesn’t just potentially suck in warmer climates, but that – quite often – it is distilleries up-north that struggle. How is that possible? Don’t they have access to cold water? Yes, they do, but since it is so cold, they are afraid the water might freeze, when put outside. “Outside” as in that’s where their chiller sits. Why a chiller in colder climates? Because of the warm summers.

What do distillers up-north do, in order to prevent their cooling water from freezing? They add glycol to it. “Glycol” as in an anti-freeze agent that has close to no cooling capacity. By adding it to the cooling water (and water has an amazing amount of cooling capacity), they are now diluting the overal cooling capacity of the coolant!

An example. Say, a distillery from Canada is advised to add a chiller to manage the temperature of their coolant downward. Because it can get pretty warm in the summer, right? And since it gets pretty cold in winter … well, they add 25% glycol to prevent the coolant from freezing over in winter. Since the cooling capacity of the glycol is very low, they (cutting only minor corners here) just “diluted” the cooling capacity with 25%! Start to see why cooling can suck even up-north?

The solution? Well, iStill provides one. Our bigger stills (500 liters and more) are now equipped with an additional pre-cooler. It adds 30 to 40% additional cooling capacity, off-setting slightly warmer cooling water and/or the addition of a limited amount of glycol.

But our pre-cooler is a band-aid. A great band-aid, but a band-aid altogether. Here’s what you, the distiller, needs to do. In a warmer climate, add a chiller and let it chill water. You don’t need anti-freeze. In a cold climate, limit the amount of glycol to a minimum and set your chiller up inside rather than outside.

Chill to know your cooler works just fine …

3 thoughts on “Why Cooling Sometimes Sucks!

  1. I have been using a precooler Cyprus and with 30 degrees celsius water, I manage to keep everything below 35 degrees celsius. No glycol, no chiller no closed circuits.

    • No closed circuits is another great way forward. So many chillers are closed loop and then the impeller stops working because air is trapped inside … Someone once said: the best solution is no solution, the best part is not to have that part, the best process is no process. KISS to the max!

      • Are open circuits not unsustainable from a water usage perspective? Example, our city is implementing fines for dumping our cooling water from the still, we must now use a closed loop.

        Theoretically, Is the answer not simply to increase the size (efficiency) of the chiller to compensate for the 25% reduction in Glycol-laden cooling power by increasing flow rate by let’s say an additional 25%?

        (We’d love to use the precooler but alas our ceiling height doesn’t permit on the 2000).

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