Air Compressors
Compressed air is a vital plant utility, since virtually every phase of manufacturing depends upon it. A compressed air system can be expensive to operate compared to other plant utilities. Since it takes 7 to 8 horsepower (hp) of electrical energy to produce 1 hp of effect at the end user point, efficiency is very important. Because of this, you must choose systems and deal with operational matters carefully.
A well-controlled compressor runs in one of two ways. Some compressors will run as “base load” units where they will be either at full load or off. Some will need to run in “trim” or “swing” duty where they vary their output to take up the remainder of the load. In one-compressor systems, the compressor runs in trim duty.
For base duty, the most important thing to consider is full-load efficiency rating of the compressor. For trim duty, the most important thing to consider is part-load energy consumption.

Air Dryers
The type of air dryer and how it operates can save significant energy. Air drying equipment can use as much as 20 percent of the total system power. In extreme cases of faulty or poorly-sized heatless desiccant or membrane dryers, the purge flow consumed by the dryer can be the largest single air consumer in a facility.
Depending on the dryer, the cost of drying compressed air can range from one percent to 20 percent of the compressed air system's energy consumption. Higher percentages are common in lightly-loaded systems with oversized air dryers. In general, the drier that the air must be, the higher the drying cost.
If you choose this type of air dryer, you can save energy by installing a refrigerated dryer operating in a cycling on/off mode, using a thermal mass to maintain a more constant dew point output.
When drier air is required and a desiccant air dryer is chosen, you can make significant savings by choosing dew point-sensing controls. These limit costly dryer regeneration to only that needed to maintain the rated dew point output through all compressed air system flows and moisture levels.

Boilers
The most energy-efficient system for supplying both heat and electricity is a cogeneration system. These systems generate both reliable electricity and heat while reducing emissions and saving money. A cogeneration system consists of a gas turbine or reciprocating engine and a heat recovery steam generator, which is a type of boiler. If an old boiler requires major improvements, this may be the time to replace it with a cogeneration system.
Condensing boilers extract heat from the water vapors as it condenses out of the flue gas. These boilers can be 95 percent energy efficient or higher. New, non-condensing models are only 70 to 80 percent efficient.
Where low-temperature hot water is wanted – for example, for space heating – a condensing boiler is the most efficient. Where high temperatures are wanted and there is no means to cool the return below the flue gas dew point, condensing is unlikely, so consider a mid-efficiency boiler.
It is crucial to thoroughly discuss existing and potential needs with suppliers because of the higher cost of a condensing boiler. Long-term fuel costs and other factors must also be considered.
Oversize boilers are commonly installed to handle peak demand and anticipate possible expansion. This is wasteful since oversize boilers rarely operate at peak load, and their part-load efficiency can be as much as 20 percent lower.
Several smaller units can be more efficient and economical than a single large one. They can be staged (or “sequenced”) to operate at or near peak efficiency if piped and controlled appropriately. An added up-front benefit is lower installation costs since small boilers do not require a crane to be installed.
For retrofitting, a multiple boiler approach can improve the seasonal inefficiency of large, old boilers. A small boiler can supply basic heating, and the large boiler fires only when necessary to supplement the heating during periods of high heating load.

Gearboxes
Utilization of high quality gearing with superior surface finish on the gear teeth combined with the incorporation of low-friction seals and bearings all serve to maximize the power efficiency of the enclosed gearing product lines.
From the point of view of the user (or potential user), perhaps one of the most important factors in selecting a unit to assure that its efficiency is being optimized for the application is unit size. In short, make sure that the gearbox is properly sized for the application. Prior to ordering the speed reducer from the manufacturer, it is imperative that the application power requirements and demands are clearly understood. Utilization of the appropriate service factor for the speed reducer must be taken into consideration and applied.
If the gearbox is unnecessarily oversized – specifically, if the power capacity of the gearbox greatly exceeds the power of the applied motor combined with the application service factor, much of the motor power will be used to overcome the constant losses within the gearbox thereby leaving little additional usable power/torque for the application itself. In short, this would be a situation where the speed reducer is yielding a very low efficiency.
Also, consider the method by which the gearbox is attached to the driven shaft. Is it possible to directly couple the output shaft of the reducer directly to the driven shaft? This may be preferred, from an efficiency point-of-view, since the use of belts and/or chains generates friction or possibly slippage at their interface which, in-turn, leads to additional efficiency losses.

Motors
Many manufacturers now offer motors that are more efficient than the regulated minimum efficiency models.
Motors with the NEMA Premium™ designation optimize the efficiency of motor systems, reduce electrical power consumption and costs, and improve reliability.
NEMA Premium™ motors are built with superior materials such as high-quality silicone steel laminates and are manufactured with optimized designs. The result is more work output for the same amount of energy consumed. Thanks to their improved design, NEMA Premium™ motors usually also have higher service factors, longer-lasting insulation and bearings, lower waste heat output and less vibration than standard motors. The most efficient models are so reliable that manufacturers typically provide longer warranties for them.
NEMA Premium™ motors can replace motors on most original equipment manufacturers' (OEM) products for almost all applications, including pumps, fans, blowers, air compressors, cooling and refrigeration equipment, hydraulic packages and material-handling equipment. Although NEMA Premium™ motors are well suited to virtually any common induction motor application; they are particularly well suited to applications that have a long duty cycle (over 6000 hours per year) or where reliability is critical.
Some energy-efficient motors will run slightly faster than the motor being replaced, and this speed increase can negate the energy efficiency of the new motor. For centrifugal fans and pumps, the power is proportional to the speed cubed. For example, a 1 percent increase in speed will result in 3 percent more electrical consumption. If the new motor is 2 percent more efficient than the old one, the energy-efficient motor will actually use 1 percent more energy than the old one. Always select a new motor that has a full-load operating speed that is less than or equal to that of the motor being replaced.
Minor speed variations can be sometimes be adjusted in belt-driven equipment by changing the pulley size; in direct-drive pumps, speed can be adjusted by trimming impellers.
Use a variable speed drive (also called a variable frequency drive). For fluctuating loads with long duty cycles, a variable speed drive can help minimize energy consumption for an induction motor. A variable speed drive works as a frequency inverter and can regulate, over a wide range, the speed of the motor to fit the load demand. Energy efficiency is increased, in some applications by as much as 50 percent.

Pipes
Every industrial facility has a piping network that carries water or other fluids. According to energy experts, 16% of a typical facility’s electricity costs are for its pumping systems. If your application permits, epoxy-coated steel or plastic pipes can reduce friction factor by more than 40%, proportionately reducing your pumping costs.

Pumps
Pumping systems account for nearly 20 percent of the world's electrical energy demand and can range from 25 to 50 percent of the energy used in certain industrial operations.
There is a tendency to oversize pumping units to meet anticipated future requirements. This can result in the need to throttle or operate the equipment at a higher capacity than necessary. Aim to operate the pump near the best efficiency point (BEP) at all times. Select a pump with room for a larger impeller to handle possible future increases in capacity. Consider trimming the impeller (reducing its diameter) in a pump that is too large for the current application.

Consider a variable speed drive. A variable speed drive can lower losses caused by throttle valves and bypass lines and is cost-effective in systems that have variable flow requirements. Most manufacturers offer compatible variable speed drives.Use two smaller pumps instead of one large pump so that excess capacity can be turned off. Two pumps can operate in parallel during peak demand, with only one pump operating during low demand. An alternative strategy is to combine a variable speed pump with one that runs at constant speed.

Transformers
Transformers reduce the voltage of the electricity supplied by your utility to a level suitable for use by the electric equipment in your facility. Since all of the electricity used by your company passes through a transformer, even a small efficiency improvement will result in significant electricity savings. High-efficiency transformers are now available that can reduce your facility's total electricity use by approximately 1 percent. That's good for your company; it's also good for the environment. Reduced electricity use provides cost savings for your company; it also reduces air emissions from electricity generation.

Every transformer has its own unique efficiency profile based on its load and no-load losses, so a transformer's energy losses will depend heavily on building and equipment usage patterns. Large transformers tend to be heavily loaded, while transformers that serve smaller industrial and commercial customers tend to be more lightly loaded. The better you understand your facility's load profile, the more effectively you will be able to choose the most efficient transformer for your facility.

It is important to remember that transformers are rarely run at their full-load. In fact, 35 percent is the accepted industry average transformer load. A survey of dry-type transformers actually found the average load factor in manufacturing facilities to be only 14.1 percent. The efficiency of any transformer at this low load is very different from its efficiency at full load.

Some purchasers believe that choosing a transformer with a low temperature rise will result in an energy-efficient transformer, but this is not always the case. In general, the lower the temperature rise of a transformer, the lower its internal losses, but when manufacturers design a transformer for a low-temperature rise, they often decrease the load losses but increase the no-load losses. This is due to the cooling method, i.e. fans. If a transformer is running at a very low load, this method of selecting a transformer can actually result in choosing a less efficient model.

Turbulators
Turbulators can be a cost-effective way to reduce the stack temperature and increase the fuel-to-steam efficiency of single-pass horizontal return tubular (HRT) brick-set boilers and older two- and three-pass oil and natural-gas-fueled firetube boilers. Turbulators are not recommended for four-pass boilers or coalfired units. A four-pass unit provides four opportunities for heat transfer. It has more heat exchange surface area, a lower stack temperature, higher fuel-to-steam efficiency, and lower annual fuel costs than a two- or three-pass boiler operating under identical conditions. New firetube boilers perform better than older two and three-pass designs.
Turbulators can also be installed to compensate for efficiency losses when a fourpass boiler is being converted to a two-pass boiler because of door warpage and loose and leaking tubes. Turbulators are a substitute for a more costly economizer or air-preheater. Current turbulator designs do not cause significant increase in pressure drops or contribute to soot formation in natural-gas-fired boilers. Turbulators are held in place with a spring lock and are easily removed to allow for tube brushing.

UPS systems may also convert unregulated input power to voltage and frequency-filtered AC power. Thus, the UPS will provide stable power and minimize the effects of electric power supply disturbances and variations.The first decision to make is on the type of protection you require. Offline UPS systems offer higher efficiency than online UPS systems but provide less protection against disturbances in the power supply. Buy offline units only if the level of protection required by your application warrants the choice and you can tolerate a very brief loss of power during the switchover to UPS power.Many UPS systems are oversized to accommodate possible future load expansion. The actual installed load may be only a fraction of the UPS power rating. Since the efficiency of UPS systems can drop considerably with decreasing load, cost savings may be significant when the UPS power rating is closely matched to the existing load.Some online UPS systems can be manually switched to line-interactive mode, increasing efficiency in exchange for lowering protection. This option is worth considering where you can sustain power supply disturbances but periodically need the full protection of an online UPS.All associated cables and components must be installed correctly, and the UPS must be installed with adequate ventilation for maintenance and operation. Maintaining the manufacturer's specified range of operating temperatures is important for reliability and longer UPS life. The UPS may require a separate, dedicated air-conditioning unit. Consider UPS and air-conditioning noise when locating the unit in or near work areas.

Variable Frequency Drives
Adding a variable frequency drive (VFD) to a motor-driven system can offer potential energy savings in a system in which the loads vary with time. VFDs belong to a group of equipment called adjustable speed drives or variable speed drives. (Variable speed drives can be electrical or mechanical, whereas VFDs are electrical.) The operating speed of a motor connected to a VFD is varied by changing the frequency of the motor supply voltage. This allows continuous process speed control.
Motor-driven systems are often designed to handle peak loads that have a safety factor. This often leads to energy inefficiency in systems that operate for extended periods at reduced load. The ability to adjust motor speed enables closer matching of motor output to load and often results in energy savings.
A VFD may be used for control of process temperature, pressure or flow without the use of a separate controller. Suitable sensors and electronics are used to interface the driven equipment with the VFD.
Maintenance costs can be lower, since lower operating speeds result in longer life for bearings and motors.
Eliminating the throttling valves and dampers also does away with maintaining these devices and all associated controls.
The ability of a VFD to limit torque to a user-selected level can protect driven equipment that cannot tolerate excessive torque.
Controlled ramp-up speed in a liquid system can eliminate water hammer problems.

Welding
Modern inverter power sources have high energy-conversion efficiencies and can be 50 percent more efficient than transformer-rectifier power sources.
Modern inverter power sources for idling power requirements are 1/20th of conventional transformer-rectifier power sources.
Modern inverter power sources have power factors that are close to 100 percent; transformer-rectifier power source percentages are much lower, which reduces electricity consumption.
Modern inverter power sources are four times lighter and much smaller than transformer-rectifier power sources. They are thus more portable and can be moved by one person instead of four, making it possible to bring the welding equipment to the job, not vice versa.