• Without top management level sup- port, energy saving efforts will fail.
• Lack of metrics to measure the suc- cess of an energy reduction project hinders the next project.
Steps to Success Metalcasters should follow several
basic principles to achieve successful energy management (Fig. 2): Make a commitment. The first
step is to establish energy leader- ship and accountability. Previous studies have demonstrated that the single biggest key to a successful energy management program is a dedicated “energy champion” who
Fig. 2. The first step in energy manage- ment is making a commitment to develop a comprehensive energy program, including clear goals and measurement metrics for evaluation.
ENERGY SAVING CASE STUDIES Sub-Metering
Many metalcasting facilities receive a single electric or gas bill and don’t know specifically where the energy is being used. One gray iron facility installed sub-meters at multiple points throughout its operation to combat this problem. The metal- caster installed meters on each furnace, compressor and bag house. The process included computerized monitors to provide real-time electrical consumption for each piece of equipment and precise minute-by-minute KwH use.
The ferrous caster identified an excessive energy spike on a single furnace and air compressor practices that led to waste. An $80,000 initial investment in the sub-meters and monitoring software resulted in a 10% energy reduction in the first year.
Air Compressors
Industry studies have shown the average metalcasting facil- ity may produce 50% more compressed air than is required due to artificial demand and overproduction (not knowing how much compressed air the operator actually needs), air leaks and poor practices. Ask the following questions to reduce overproduction: • Do you know your actual demand (i.e. how much air you need)?
• Does this need vary throughout the production schedule, or is it constant?
• What air pressure do you need? • What quality of air do you need?
All air leaks are wasted production and should be tagged for
repair. One metalcasting facility that began to diligently moni- tor and repair leaks and air production discovered significant overproduction and was able to take 375 horsepower of com- pressed air production offline, resulting in an annual savings of approximately $170,000.
Plant Lighting
An aluminum casting facility had approximately 360 high pressure sodium light fixtures, covering more than 200,000 sq. ft. of space. Since the bulbs consume about twice as much energy as T8 fluorescent fixtures, the facility identified an opportunity to reduce electrical consumption and receive an energy rebate through a state sponsored energy program. Working with a local lighting provider to find the best fixture and appropriate replacement for each area of the plant, the metalcaster installed 360 six- and four-bulb T8 fluorescent fix- tures. Low traffic areas, such as the warehouse space, were outfitted with motion sensors to provide further reductions. The total cost of the lighting investment and installation was $70,000, and the company received a state rebate of $33,615. The estimated savings using the new lighting is more than $55,000 per year with a return on investment of about eight months, including the rebate. The estimated electrical power reduction will decrease the plant’s carbon dioxide output by 443 tons per year, 2 tons of sodium dioxide per year and 1 ton of nitrogen oxides per year, the equivalent to saving 55,716 gallons of gasoline or removing 109 cars from the road.
April 2011 MODERN CASTING | 21
Image courtesy of ENERGY STAR
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