Melting of metals and other materials has been a vital manufacturing process for several thousand years, producing molten liquids that can be poured and solidified into useful shapes. Although the basic process continues to be the same, the utility and energy efficiency of manufacturing cast products has come a long way.
 
Even though significant improvements in the melting of metals processes have been made, the primary metals industry still consumes over 144,500 million kWh of electricity annually. More than 90 percent of that energy is used for direct processes such as metals heating, machinery drives and chemical processes related to creating the end product.
 
Today, manufacturers look to energy efficiency to reduce production costs and improve the bottom line. The following tips can start you on your way to energy savings:

• Consider installing industrial heat pumps. Industrial heat pumps (IHPs) use waste heat from other processes as the heating sources. They use this waste heat to deliver higher temperatures for use in other industrial process heating or pre-heating as well as for space heating. IHPs represent a worthwhile method of improving the energy efficiency of industrial processes and/or reducing primary energy consumption. Compared to other heating sources and to heat pumps using other heat sources, IHPs often have very high coefficients of performance.
   
• Consider installing recuperators and regenerators. Recuperators are heat exchangers that extract heat from the furnace waste gases to preheat incoming combustion air. Recuperators can achieve approximately 30 percent in energy savings compared to cold-air combustion systems. Regenerative burners use a porous ceramic bed for short term heat storage. Regenerators are very efficient and can recover up to 85 percent of the waste heat from furnace gases. Compared to cold-air burners, regenerative burners can achieve energy savings of as much as 50 percent.
   
• Use ceramic fibre materials for hot face lining in furnaces. Using low conductivity, low thermal mass ceramic fibre materials can make a major contribution to energy savings in many furnaces. Using these materials can minimize heat losses absorbed by the furnace structure and through the furnace walls and roofs.
   
• Use high efficiency electric motors. Electric motors are considered the work horse in many industrial applications, often operating for extended periods of time and consuming significant amounts of energy in the process. Not all motors operate with the same efficiency. When installing new motors, consider using high efficiency motors on all units one horsepower or greater. This is increasingly important for motors that operate for extended periods of time. Installing premium or high- efficiency motors can save up to three percent in motor- energy consumption.
   
• Eliminate leaks in compressed air lines and valves.  Air leaks around valves and fittings in compressed air lines can represent a significant energy cost in manufacturing facilities. Sometimes up to 20 percent of the work done by the compressor is used to make up for losses from air leaks. Therefore, air leak elimination should be a priority for any industrial facility. Sonic or infrared testing devices can be used as cost-effective tools for determining air leak locations.
   
• Recover waste heat from oven, kiln and heating equipment. Consider installing heat recovery systems to make use of heat energy that otherwise would be lost to the surroundings. Heat recovery systems use hot media (typically air or fluids) leaving a process to preheat other, or sometimes the same, media entering the process. Energy that otherwise would be lost does useful work. Waste heat can be recovered from a variety of different types of equipment and processes, such as compressors, furnace and boiler exhaust, and hot liquid blow-downs.
   
• Repair and eliminate steam leaks. Significant savings can be realized by repairing leaks in steam and condensate return lines. Steam line leaks result in higher steam production requirements from the boiler to meet the system needs. Condensate return lines that are leaky return less condensate to the boiler, thus requiring more energy to heat cooler make-up water than hot condensate return water. Leaks most often occur at the fittings in the steam and condensate pipe systems.
   
• Insulate pipes and equipment to prevent heat loss.  Insulation is an important part of every manufacturing plant where any transfer of heated fluids or gases takes place. Any surface above 100º F should be insulated. This includes all hot water and steam pipes and fittings. Properly insulated pipes, tanks, and other equipment can save a significant amount in energy costs. 
   
• Replace T12 fluorescent lamps with higher efficiency T8 fluorescent lamps and electronic ballasts. Retrofitting ceiling lighting with higher efficiency T8 lamps and electronic ballasts is a cost-effective way to reduce energy consumption. Depending on the ballast used, the T8 lamp often delivers the same lumen output for 20 to 40 percent fewer watts than T12 lamps. The benefits of installing higher efficiency T8 lamps and electronic ballasts include a decrease in energy consumption and costs, an increase in light quality and longer lasting lamps, which means reduced maintenance costs.
   
  Before installing higher efficiency lamps or ballasts, measure the light levels at each working height level for each area of the facility to determine whether more or less light is required. Suggested light levels are published by the Illuminating Engineering Society of North America. Also consider using T8 fluorescent lighting in high-bay applications that may currently use metal halide or high-pressure sodium fixtures for increased energy efficiency.
   
• Replace incandescent lamps with compact fluorescent lamps (CFLs). CFLs are a more energy-efficient lighting source than incandescents, typically using 75 percent less energy and lasting 10 times as long while producing 90 percent less heat.
   
• Install ENERGY STAR^®-qualified exit signs to replace signs with incandescent or fluorescent lamps. Exit signs that have earned the ENERGY STAR rating operate on five watts or less per sign compared to standard signs, which can use as much as 40 watts per sign. One ENERGY STAR®-qualified exit sign alone can save about $10 annually on electricity costs and can last up to ten years without a lamp replacement, compared to less than one year for an incandescent.
   
• Install automated lighting systems, controls or sensors to reduce interior and exterior lighting energy costs. Lighting controls such as dimmers, timers and motion sensors may be used in closets, restrooms, offices, storage spaces and other areas that are not in constant use. These relatively inexpensive devices can help ensure that lights are turned off in areas that are not in use. It is recommended that lighting controls be inspected periodically to be sure that they are operating properly.