Warehouse and Manufacturing

Compressed Air

Fix Air Distribution Leaks
Air leaks can be a significant source of wasted energy. A typical plant that has not been well maintained could have a leak rate from 20 percent to 50 percent of total compressed air production capacity. Leak repair and maintenance can reduce this number to less than 10 percent. Overall, fixing leaks in a compressed air system is projected to reduce annual energy consumption by 20 percent.

Install Equipment Air Shutoffs
Install a simple solenoid valve so that equipment can be turned off when it is no longer using compressed air. Check compressed air distribution systems when equipment has been reconfigured to ensure no air is flowing to unused equipment or obsolete parts of the compressed air distribution system.

Clean Pipeline Filters
Blocked pipeline filters increase pressure drop. Keep the compressor and intercooling surfaces clean and foul-free by inspecting and periodically cleaning filters. Use filters with just a one pound per square inch (psi) pressure drop. The payback period for filter cleaning is usually less than two years. Fixing improperly operating filters will also prevent contaminants from entering into tools, which causes them to wear out prematurely.

Monitor Compressed Air Systems
Proper monitoring will help identify blockages and fouling that degrade energy efficiency. Routine monitoring should include:

• Pressure gauges on each receiver or main branch line
• Differential gauges across dryers and filters
• Temperature gauges on compressor and its cooling system
• Flow meters that measure the air used quantity
• Dew-point temperature gauges to monitor air dryer effectiveness
• Kilowatt-hour and hours-run meters on the compressor drive.

Use Compressed Air Mindfully
Compressed air is one of the least energy-efficient systems in an industrial plant because of the amount of energy required for compression and distribution. If compressed air is used, it should be at the minimum quantity for the shortest possible time, and it should be constantly monitored and reweighed against alternatives.

Use Lowest Pressure Levels
Try to use the lowest possible pressure level to operate the system to save energy and money.

HVAC

Use Flue Gas Monitors to Control Boiler Processes
Flue gas monitors maintain optimum flame temperature and monitor carbon monoxide (CO), oxygen and smoke in boiler systems. Just a 1 percent air infiltration can result in 20 percent higher oxygen readings. A higher CO or smoke content in the exhaust gas is a sign that there is insufficient air to complete fuel burning. Using a combination of CO and oxygen readings, it is possible to optimize the fuel/air mixture for high flame temperature (and thus the best energy efficiency) and lower air pollutant emissions.

Repair Boiler and Flue Leaks
Often excessive flue gas results from leaks in the boiler and/or in the flue. These leaks can reduce the heat transferred to the steam and increase pumping requirements. However, such leaks are often easily repaired, resulting in 2 to 5 percent energy savings for the boiler.

Return Condensate to Boiler
Reusing hot condensate in boilers saves energy, reduces the need for treated boiler feed water and reclaims water at up to 212 F of sensible heat.

Improve Boiler System Operations
Designing the boiler system to operate at the proper steam pressure can save energy by reducing stack temperature, piping radiation losses and leaks in steam traps. Costs and savings will depend heavily on the current boiler system utilization at individual plants.

Repair Steam Distribution System Leaks
As with steam traps, steam distribution piping networks often have leaks that can go undetected without a regular inspection and maintenance program. The U.S. Department of Energy estimates that repairing leaks in an industrial steam distribution system will lead to energy savings of 5 percent to 10 percent.

Motors

Improve Motor Operations
For equipment that runs at different speeds, consider installing Adjustable-Speed Drives or Variable-Speed Drives to better match speed to load requirements for motor operations, and therefore ensure that motor energy use is optimized to a given application. Energy savings  realized may be as high as 60 percent.

Improve Motor Cooling
Poor motor cooling can increase motor temperature and wind resistance, shortening motor life and increasing energy consumption. Keep motors and compressors properly lubricated and cleaned.

Manage All Your Motor Systems
Remember, motors are used in your process equipment — HVAC, air compressors and other key systems.

Implement a Motor Management Plan
A motor management plan is an essential part of a plant’s energy management strategy. It helps to support long-term motor system energy savings and to ensure that motor failures are handled quickly and cost effectively. To build a sound motor management plan you should:

• Prepare for motor failures by creating a spares inventory
• Develop purchasing and repair specifications
• Implement a predictive and preventive maintenance program
• Write guidelines for proactive replace and repair decisions

Sources: energystar.gov and Business Energy Advisor.