Case Study: SUCCESS IN TAKING THE HEAT
Our Saratoga Springs, New York, beverage can plant has a multi-year track record of improving energy efficiency. In 2014, employees engineered a method to recover heat from the plant’s closed-loop cooling water system and reuse it for incoming process water.
When water circulates through air compressors, coolers, air dryers, vacuum pumps, decorator inkers and various other process equipment, it removes heat created during the manufacturing processes. Before the heated water reaches the cooling tower, it now travels through a heat exchanger that transfers the heat to incoming makeup water, which is then used in the can washing process. The water is then transferred to the cooling tower at a lower temperature; reducing the load on the cooling tower, which utilizes energy to cool the water. During periods of high humidity, the system previously experienced heat pump failures, compressor inefficiencies, and air dryer faulting due to high temperatures.
Reducing the cooling tower’s load benefits the plant through increased performance during hot summer days and by reducing operating costs throughout the year. The plant noted a heat reduction of about 22 percent of the cooling tower capacity with an additional 20 percent reduction in cooling tower fan speed – both extending the life of the tower. To date, the project has recorded water savings of at least 2,000 gallons per day from water typically lost in the cooling tower due to evaporation and natural gas savings of 90 kilowatt hours per day, equal to $18,000 per year.
With a total project cost of approximately $25,000, the direct savings from gas, electricity, water and improved efficiency of the compressors will cover this expense in less than a year.
HEATING AND COOLING
Heating, ventilation and air conditioning (HVAC) control during the heating season is another energy efficiency opportunity. Central control systems and higher awareness of HVAC-related energy usage and costs are driving progress. We identify optimal temperatures for different areas within a plant and educate employees on how they can achieve these temperatures with the lowest energy input. Installing heat curtains, for example, reduces heat or cooling loss.
Though Ball Aerospace only accounts for less than 2 percent of Ball’s energy consumption, optimizing energy usage is a high priority for this business. Cleanroom operations are a major energy usage area. In these rooms, the levels of environmental pollutants, such as dust and microbes, are reduced to enable sensitive aerospace instruments and other technologies to be manufactured and tested. We continue making improvements to reduce energy consumption in operating these cleanrooms. For example, we recently modified the HVAC automation control system for one of our large cleanrooms to reduce air flow during unoccupied hours (weekday nights and weekends). The estimated electricity reduction is about 1 million kilowatt hours per year, equivalent to more than 758 metric tons of carbon dioxide equivalent emissions.