Evaporative Technologies for Process Equipment and Space Cooling
Refrigerant-free evaporative cooling systems can provide energy savings in industrial settings.
With advances in design, manufacturing and controls, process and comfort cooling and heating systems present opportunities for energy savings in industrial settings. While not a new technology, advancements in refrigerant-free evaporative cooling system technologies make them more attractive in industrial applications.
In industries that require process cooling, especially where products such as pharmaceuticals, food and beverages must be kept at certain temperatures by law, energy-efficient cooling can reduce operating costs by as much as one-third while keeping facilities within temperature requirements. For new or retrofitted cooling equipment for industrial facilities, decision makers should consider:
- High performance air-handling efficiencies using direct-drive plenum fans with variable frequency drive (VFD) controls that reduce energy consumption when equipment is operating at part load (which is often more than 90 percent of the time). Variable-speed fans are the preferred choice from a power standpoint because there is a direct relationship between fan speed and power consumed. For example, decreasing speed by 10 percent will decrease horsepower by 33 percent.
- Refrigerant-free evaporative cooling technology, which has been shown to reduce power usage significantly when compared with traditional air- conditioning.
- Direct digital controls that help monitor and adjust HVAC systems (on site or remotely via the Internet) for cost, energy efficiency and comfort.
Ensuring Compliance with Regulations
Two challenges facing heavily regulated industries such as food and pharmaceuticals are:
- Compliance with evolving regulations for maintaining, measuring and documenting temperature controls.
- The need to comply with new, tougher standards for energy efficiency.
Whether from farm-to-fork or from bench-to-bedside, a number of governmental bodies — the Food and Drug Administration, the Environmental Protection Agency, the Occupational Safety and Health Administration, the World Health Organization and the Consumer Product Safety Commission — impose regulations and guidelines.
In the pharmaceutical industry, and increasingly in food processing and storage, sophisticated monitoring and recordkeeping procedures to track temperature and humidity levels are mandatory. Another trend — bigger, taller production and storage facilities — makes the task even more challenging.
Open-floor-plan industrial and warehouse settings face natural heat stratification: the air temperature 1’ off the floor is going to be much cooler than the air temperature 30’ up. The temperature differential can be as much as 1°F per vertical foot. In highly regulated, temperature-sensitive industries, maintaining consistent temperatures within the prescribed criteria is critical, no matter if the product is being processed on the floor or stored on racks high overhead.
Adding yet another level of compliance complexity is the new minimum Fan Efficiency Grade (FEG) requirements adopted by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). They are expected to be included in all U.S. commercial construction codes within a year.
The best solution to the sometimes-competing challenges of compliance is not adding air-conditioning capacity. Efficient air-handling systems can rotate the air throughout the space and reduce temperature disparities and dead spots. Higher rates of air-volume circulation also may improve worker comfort and productivity.
In preparation for the effect these new standards may have on their industrial facilities and warehouses, some processors may want to consider alternate approaches to process, equipment, space and comfort cooling. One evaporative cooling system pairs energy-efficient evaporative cooling technology with an advanced air turnover system.
Industrial Plant Environmental Comfort Equals Improved Productivity
There is plenty of science behind the correlation of workplace temperature and productivity, but the best way to understand the impact of evaporative cooling systems on productivity is from actual experience. Here are three real-life examples.
Biotech Facility. As a fast-track pilot project, one of the world’s leading biotech companies recently replaced a traditional refrigerant-based cooling system with an energy-efficient, refrigerant-free evaporative cooling system. Among the results, chemical refrigerants were eliminated; energy consumption was halved; and water consumption was reduced. Built-in digital controls provide round-the-clock data that allowed managers to monitor, track and optimize systems in real time locally or remotely.
Seating Manufacturing. With a heat-producing manufacturing process, temperatures within a foam seating manufacturing company became dangerously high on summer days. This resulted in heat stress, sick days and extended breaks for production workers.
An evaporative cooling system was installed in combination with existing equipment, to which an extension of ductwork also was added. These changes meant the cooling could be directed to the areas where workers were active. The Belding-Hatch Heat Stress Index was used to determine the impact of revised cooling system, using the highest recorded outside temperature (98°F [36°C]). Results show that the heat stress index was reduced from 70 (very severe heat strain) to 20 (mild to moderate heat strain) — a significant improvement in providing worker comfort through heat relief.
Paint Curing. A leading auto manufacturer using large paint ovens to bake paint onto the bodies of cars in its facility in Georgia experienced extreme heat coming out of the ovens and spilling into the nearby inspection areas. It was not uncommon for temperatures to be in excess of 110°F (43°C). A spot evaporative cooling system was put in place that vented a cool, clean curtain of air between the cars and the inspectors. Discharge from the cooling units was lowered to approximately 77°F (25°C), a more than 30 percent reduction in air temperature.
In an increasingly complex world for process cooling decision-makers, cost, compliance and comfort can be competing challenges. There are solutions. They include proven technologies such as evaporative cooling technology with advanced air-handling capabilities. PC