Cooling Tower?

[Silk City Distillers]

Anyone running a cooling tower and care to share details? Sizing, flow rate, input/output temps, region? Effectiveness?

Suspect that it would be considerably more cost effective from an initial investment and an ongoing operational perspective than a larger portable chiller unit running indoors. Out in hot and sticky NJ, suspect it will be largely worthless in July and August, but that still gives us a very wide operating window (7 months) from March to November.

[MG Thermal Consulting]

James,

At best, an evaporative product, be it a cooling tower or a newer item like a closed loop "adiabatic" (think like spraying water from a hose onto a coil), will be able to cool water only to within about 8 degrees of wet bulb temperature during summer or any other time their is high humidity. during summer the wet bulb in NJ is probably 76 degrees, so the best you can get is 84F, impractical for much of anything at a distillery. the other thing you need to be careful of is that the cooling tower water will need to be treated vigorously and strained with a heavy duty strainer to get everything on the cold water loop or you will scale up inside jackets and still condensers, so it would be better to install a intermediate plate exchanger to isolate the process flow from the tower flow.

You're right about winter operation, but even in the mountains up on CT/VT area, a distiller I supplied with a winter glycol cooler, got from Nov to March, like 6 to 6.5 months. You may get about the same, but will still need a chiller like a couple distilleries I supplied such a method to.

Oh, and how close are you to the ocean? Salt air and towers don't mix without special materials used on the tower.

Good luck and give me call if you have any questions.

Mike G

770-995-4066

[OldSpye]

Any chance you'd be able to dig a hole in the ground? Stick a coil 15' under the surface and you'd be able to out-do the performance of a cooling tower.

[MG Thermal Consulting]

I had one guy dig a hole, put in a poly/reinforced cistern. fill with glycol mix and draw it out with a couple pumps, one for process equipment and the other for a dry cooler- worked all winter and so far is able to keep up. He was anticipating adding a small chiller, but so far hasn't contacted me.

He was hoping to work up some temperature profiles on paper, but he's been busy.

Location- near St. Louis.

[Silk City Distillers]

Thanks Mike - I hadn't considered one of those dry cooler units, not sure what the cost differential is compared to a standard cooling tower. Small cooling towers (10-20 ton) look to be pretty darn cheap.

Agree it couldn't be the only option, but there has got to be a better way then running the chiller all year round. Not to mention the fact that we've got limited chiller capacity. If investing in a tower vs a larger chiller is more cost effective, reduces operating costs, and improves sustainability, I'm all for it. Just don't know if it's going to live up to that.

Really just wish someone would bring the free lunch back.

My initial thought was to run the condenser/heat exchanger recirculating loop back through the tower before returning to the reservoir. Heck if I could take down the coolant return temperature down to 84f, I could significantly extend the capacity of the reservoir and the ability for the chiller to keep up. The other angle where I thought this could really shine is initial cooling of cereal mashes from 212-150. We're talking about coolant return temps way above wet bulb + offset.

[MG Thermal Consulting]

James,

Again, you will need a intermediate exchanger for the cooling tower in your scenario or the the tower film will scale up like crazy and the amount of make-up water would increase, %-wise.

The closed circuit glycol cooler I most generally supply will perform at 10 tons rejection in winter and if you used it to pre-cool the warm water off the mash before getting back to the chiller and with some clever piping, you could use the closed cooler in the same way in the winter for most all needs.

The picture attached shows the inside of the drycooler in mid-assembly with integral circulating pump and control box that includes the pump starter. if you are clsor to the coast, we can paint the copper coil surface to resist salt air.

I charge $2,700 plus freight for the drycooler as an option to the chiller system but it will work fine in your scenario and only have operating cost of a fan motor and pump.

The intermediate exchanger would add another $1,800 which you would need in either case.

[MG Thermal Consulting]

FYI, a picture of the glycol cooler in the field alongside the sister chiller at CT distillery.

[patrick260z]

MG, what is your cooling water flow rate max and temp delta?

Right now I've plumed a 3/4 hp pump up to an old AC Freon radiator and box fan as a pre-cooler that then is piped into a small glycol wart chiller. Glycol set at 25f, and getting nearly 50F drop, but flow rate is only about 5gpm, which means at the end of my runs, when my distillate rate is pushed, I'm not flowing enough cool water to keep temperatures under control in my still condenser.

[MG Thermal Consulting]

The glycol cooler will reject 6 tons at summer ambients, so about 10-15 GPM and 20 TD.

It is meant to run as a wintercooler, below 30F ambient where it can get wider TD's and 10 tons or above capacity.

If I were you, I would get a poly reservoir and bring it down to temp overnight with the glycol chiller- it's the cheapest way to extend cooling capacity, then if that doesn't work, look at the mechanical option.

Mike