Process Cooling as Part of a Sustainable Strategy

Feb. 17, 2015
Closed-loop systems help pharmaceutical manufacturers save water and energy

While the pharmaceutical industry continues on its road to recovery, sustainability will remain a priority for pharmaceutical manufacturers as they strive for profitable growth. One way many can make significant headway toward true sustainability — and improve the bottom line — is through the use of advanced, closed-loop process cooling technology specifically designed to lower water consumption and save energy.

Conventional cooling towers use evaporation to reduce process water temperature; closed-loop systems employ ambient air to cool the water resulting in significantly reduced water consumption and energy-related costs.

Process cooling efficiency should be on the front burner rather than the afterthought it often is. Doing so is particularly important today given increasing concern over water use by pharmaceutical manufacturers and other companies that use water-intensive processes to make and deliver products. Following are some “need-to-knows” about closed-loop process cooling when looking to improve the sustainability of a new manufacturing facility, or any operation scheduled for a plant expansion or process-cooling system upgrade.

The need for more responsible water consumption is driven primarily by the fact that while two-thirds of the Earth’s surface is water, only one-half of one percent is available for use. What’s also known is that all industry uses as much as 22 percent of the Earth’s clean water, which leaves that much less for others. Most pharmaceutical companies recognize the inherent value in conserving water use. Yet that hasn’t kept the federal government and local municipalities from pressuring manufacturers to reduce water and energy consumption and minimize process discharge into sewage systems. In fact, the U.S. Food and Drug Administration has cited poorly designed and inefficient cooling systems as an area calling for Pharma’s attention.

Many pharmaceutical facilities contain large, energy-intensive cleanrooms. Studies show that traditional chillers can account for more than 50 percent of that energy use due to the amount of cooling often needed and FDA-required filtration. Today, the total cost of fuels and electricity for the pharmaceutical industry is growing into the billions. Costs for disposal of contaminated fluids are also on the rise as local municipalities look for ways to defray the cost of treatment and disposal.

A growing concern over water consumption, heightened government attention and rising water treatment costs are among the several good reasons why many manufacturers across a number of industries have begun to rethink traditional methods to meet their cooling needs. Companies are also analyzing traditional approaches to process cooling and concluding there, too, is need for change.

Virtually all pharmaceutical manufacturers use process-cooling equipment as part of their production processes. The equipment provides cooling water for critical applications such as R&D, batch processing, cream and ointment cooling, liquid sterilization, tablet formation, packaging and much more. For decades, U.S. pharmaceutical processors have used traditional cooling towers and, if necessary, central water chillers for their process cooling needs. Yet a growing number of companies with plants in the United States are taking a cue from their European counterparts and moving away from open-loop cooling towers.
Why? The primary factor is water consumption. It’s not unusual for a typical cooling tower system to consume and dispense up to 1 to 1.5 million gallons of often contaminated water per year (per 100-ton system) for a single plant.

Cooling-tower systems create other challenges as well. Fans and pumps operate continuously, adding to energy costs. The systems also suffer from solid deposits, gasses, algae, bacteria/Legionella, microbiological growth, scale accumulation on heat exchangers and oxidation — all of these issues must be fixed with intensive maintenance and chemical treatment. Further, most all chemically treated water makes its way to the sewer eventually, creating a costly issue in the form of sewage charge expenses. So perhaps it’s no surprise that closed-loop systems, which greatly reduce or eliminate all of these problems, are growing in popularity.

While conventional cooling towers use evaporation to reduce process water temperature, a closed-loop system employs ambient air to cool the water. The end result is significantly reduced water consumption and related savings.

The operation of closed-loop systems is straightforward. A system known as Ecodry, for example, features a central cooler that provides clean water at the right temperature to processes year round. It uses heat exchangers and an internationally patented adiabatic chamber to cool water circulated to it from process machines.

Here’s an overview of the process:
1. In the adiabatic chamber, a fine mist of water is pulsed into the incoming air stream during high ambient temperature conditions.
2. The mist evaporates instantly, cooling the air before it impinges on the cooling coils that carry the process water.
3. The process drops the temperature at or below the setpoint. Cooled water is then recirculated to a facility’s process machines.
4. The microprocessor-based controller automatically maintains targeted cooling temperatures.

The major advantage to a closed-loop system is that it reuses water, allowing pharmaceutical manufacturers to move closer to their sustainability goals. Companies can save as much as 98 percent of process cooling water when compared with open-loop systems because it recirculates water continuously through the process.

Using the same clean water continuously also eliminates costs associated with consumption, disposal and treatment. Additionally, it addresses the need for clean water in virtually all pharmaceutical-manufacturing environments in keeping with sanitary restrictions. In addition, the absence of water contamination eliminates concerns associated with airborne diseases, such as Legionella.

Another major advantage of a closed-loop system in many climates is the ability to turn off chillers used for process cooling and achieve “free cooling” during the winter months. To do so, the control system monitors outside air temperature and, when appropriate, shuts down refrigeration compressors, which consume massive amounts of energy. The system reduces energy consumption by up to 95 percent when compared to equivalent capacity air-cooled central chillers, for example.

Other technologies such as variable-speed fans add to closed-loop system energy savings because at any given time the fans use only the energy needed to compensate for the exact cooling load, process temperature and outside air temperature. Compared to a typical on/off fan cycling system, a variable-speed fan and control system can reduce fan energy use as much as 25 percent.

The pharmaceutical industry’s leaders are committed to sustainability for a host of reasons, ranging from answering eco-conscience customers’ demands for better corporate citizenship, taking financial advantage of government incentives, or simply pursuing policies that conserve resources because the organization truly believes it serves their own and society’s best interests.

To get there, operations executives and managers are increasingly turning to technological advancements that allow them to cost-effectively reach the sustainability goals they’ve made. Contemporary closed-loop systems, for example, can be readily configured to:

• Save energy and reduce noise: This is done with fan exhaust diffusers. The devices keep heated exhaust air at the top of the central cooler from circulating back into the intake at the bottom of the unit to save additional energy. They also address the need for noise abatement.

• Achieve lower water temperatures — and simultaneously conserve water: Some systems can be configured with an “adiabatic booster system” that provides additional water within the central cooler. As such, it provides low, cooling tower-type temperatures in the hottest climates. Yet it still saves as much as 95 percent of process cooling water when compared with open-loop systems because it recirculates the additional water back into the adiabatic chamber.

• Gain tighter temperature control: Some systems can be designed with various heat exchanger configurations for improved temperature control. For operation in freezing climates, they can be configured with self-draining coils and recirculation pump stations to ensure performance when glycol isn’t used as a coolant.

• Save space: Fan exhaust diffusers allow multiple units to be positioned more closely together since air is no longer drawn into the bottom of the units.
Roof panels serve the same purpose when a system is configured without air diffusers. The unit can also be configured with extended legs to facilitate airflow in tight spaces. The result is a footprint as much as 30 percent smaller than the previous generation coolers, depending on the configuration.

Most pharmaceutical companies recognize that the development and production of drugs consumes large quantities of resources, including water and energy. Many have also demonstrated their commitment to sustainability, which is viewed as an ongoing and long-term initiative that requires a mix of integrated solutions and investments in the right technology. In this context, adding a well engineered, closed-loop process cooling system to the mix is clearly a step in the right direction in the effort to introduce efficiency and long-term sustainability to manufacturing operations.

Al Fosco is the Global Marketing Manager for Frigel North America. Prior to joining Frigel in 2009, Fosco spent the 16 previous years with Conair’s Water Products Division, holding sales and engineering management positions, including VP of Sales and Marketing and General Manager of Engineering. Prior to that, he spent 14 years in engineering and sales management at AEC. He has a Masters degree in Heat Transfer and Fluid Mechanics Engineering from the University of Illinois.

About the Author

Al Fosco | Frigel North America