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The Challenges Of Hawaiian Rum

This plastic cooling tower could stand up to New Hampshire winters before it was relocated to Maui to face the harsh wind, salt air and UV rays.

When Kolani Distillers, on the island of Maui, decided to convert an old sugar mill into a distillery and produce a line of rum at the site of the island's only remaining sugar plantation, they realized they had their work cut out for them -- a labor of love, hopefully.

To begin with, the father and son team, Paul and Brian Case, had to make substantial investment that met the federal code governing building facilities. These were stringent, applying to stainless steel tanks, boilers and other distillation equipment. Also, the regulations required an elaborate fire containment system, one that could make 3,500 gallons of water per minute available with a flow that could be sustained for three hours.

And, finally, they needed a reliable cooling tower that could remove the heat from the alcohol condenser system regardless of weather conditions.

Paul Case explains that the cooling tower was integral to the operation of the distillery's alcohol condensation process.

"After vaporous alcohol leaves our stills, it runs through a condenser, which condenses the alcohol back to a liquid form so we can process it," he says. "The condensers are cooled by water. So, we have to take that water, which becomes heated while cooling the alcohol, and send it to the cooling tower to reduce the water temperature, and then it goes back through the continuous condenser loop."

Selecting an appropriate cooling tower was a special consideration due to Hawaii's year round high ambient temperatures. Also, an engineered plastic tower would be effective in handling the stiff gusts of corrosive salt air that blows in off the surf just half a mile from the distillery's location in Paia. The winds on the North Shore of Maui are strong and constant enough to make it a premier windsurfing spot in the world.

However, wind-blown salt and other corrosives are the archenemy of traditional metal-clad cooling towers, which often require much maintenance such as re-sheeting, welding and rebuilding within just a few years as a result.

On the other hand, while plastic cooling towers are virtually impervious to corrosives, the relentless Hawaiian sunlight would bombard the tower with harsh UV radiation that could possibly do damage to anything but the toughest plastic material.

In the process of exploring alternatives, Case found a used cooling tower constructed of heavy-duty, engineered HDPE that was available from a computer chip manufacturer that had closed a plant in New Hampshire.

The cooling tower was a Paragon Series built by Delta Cooling Towers, and had been in service at the chip manufacturing plant since 1999.

"I did some research and found that the cooling tower manufacturer produced a quality product, and decided that for the price we could afford to buy the secondhand tower and controls, have it disassembled, shipped to Maui and reassembled at our distillery site," Case explains.

Like other Delta designs, the Paragon model is relatively light in weight, impervious to UV rays and corrosion-proof. Case adds that he was very impressed with the weather tolerance of the cooling tower, which had operated for about six years in the brutal winters of the northeastern U.S. and now has operated in the tropical sun at the distillery since 2006.

Surprising Service Call

After the cooling tower operated flawlessly for years in Maui, vandals climbed to the top of the unit and smashed the blades of the tower fan. Although not a catastrophic problem, the cooling tower could not operate in Hawaii's constant warm temperatures without the fan, so Case called the manufacturer at headquarters in New Jersey for help.

"I explained to them what had happened, and that it was a second-hand tower," he says. "Amazingly, they jumped right on it. They looked up the history of the tower and identified the fan assembly we needed to replace, and shipped it out to us with service instructions."

Case's maintenance people were able to quickly replace the entire fan assembly, which was a proprietary, non-corroding, fiber-reinforced polypropylene unit. Immediately afterward, the plant was back up and running again.

"When you consider that the cooling tower had changed hands about five years ago and was about 15 years old, Delta Cooling really took fabulous care of us," Case says.

Case adds that the design of the cooling tower fan system provides important energy savings, because the tower controls regulate the speed of the fan according to the ambient air temperature.

"In the cooler morning hours, the fan doesn't even come on," Case says. "Then, later in the day as the ambient air warms up, the fan rotates automatically at the appropriate speed to cool the condenser water from up to about 180 degrees back to about 80 degrees."

Case says the resulting energy savings are very important to companies located in Hawaii because the energy costs there are among the highest in the country.

Today, Kolani Distillers' Old Lahaina Premium Rum is sold throughout the Hawaiian Islands, and the father-son team hopes to distribute the line nationally in the near future.

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