Cooling Towers: Hunting for Energy-Efficiency & Low-Maintenance

September 17, 2018

Two summers ago, North Memorial Hospital (NMH), located in Robbinsdale, MN, presented vendors with a challenge. The hospital needed to expand their chilled water capacity while improving energy efficiency and reducing maintenance requirements. As a major medical provider in the area, reliability was also a primary concern.

Multiple vendors presented chillers and evaporative cooling tower options to the NMH maintenance staff. The extensive and competitive bidding process meant a final decision would come down to the fine details of efficiency, reliability, and cost-savings.

Maintenance Nightmares – The Baggage of Factory-Built Cooling Towers

Unlike smaller applications, NMH required large factory-built cooling towers. For these large horsepower applications, a gear drive is required as a speed-reduction mechanism. Unfortunately, gear drives pose many more maintenance issues than easy-to-replace belts used in smaller applications. Regular oil changes can be difficult and messy, the coupling arrangements require periodic maintenance, and eventually, the whole drive needs an overhaul or replacement – a massive endeavor usually requiring a prolonged shutdown and a crane.

Seeing that gear drives had long been the only option available for large factory-built cooling towers, it seemed NMH would have to deal with these same maintenance issues many others had faced for years… until Baltimore Aircoil Company (BAC) presented their Series 3000 cooling towers which used a new innovation – the Endura Drive permanent magnet motor.

Endura Drive System – The Perfect Solution


The Endura Drive system is a direct-coupled permanent magnet motor driven by a matched variable speed drive. With no speed-reduction mechanism, there are fewer parts to maintain and no energy loss associated with operation. The only maintenance required is an occasional greasing of the motor bearings.

With fewer breakdowns and higher energy efficiency, it was clear the BAC Series 3000 with Endura Drive represented the lowest cost of ownership option without sacrificing reliability and effectiveness. It was a no-brainer – the hospital staff awarded the bid to BAC.

Since the installation two summers ago, the cooling towers have provided the hospital reliable, efficient, and quiet operation without the pains of costly and difficult maintenance that gear drives bring.

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