Managing your energy use wisely can help your business increase productivity, keep your customers and employees comfortable and reduce your utility costs.
Consider purchasing premium energy-efficient motors when installing new motors or replacing existing motors. Premium efficiency motors are 1 to 4 percent more efficient than motors meeting federal minimum efficiency standards. Because many motors operate 40 to 80 hours per week or more, even small increases in efficiency can yield huge energy savings. Motors should also have the proper horsepower rating for the load - they should not be oversized.
Variable Frequency Drives (VFDs) can be used with motors to help reduce energy costs. VFDs are electronic systems used to control motor speed by changing the frequency and voltage supplied to the motor. VFDs can result in substantial energy savings, especially for varying loads. Small reductions in motor speed can also yield substantial energy savings. For example, a 20 percent reduction in motor speed can reduce energy consumption by nearly 50 percent. Pump, fan and compressor systems with variable loads should be considered for retrofit with VFDs.
Consider installing cogged or synchronous belt and pulley drive systems on motors using V-belt drives. Synchronous belts operate with less slippage and produce less heat than standard V-belts, which depend upon tension for power transmission. Lower tension also reduces motor load and bearing wear. The nominal efficiency rating for V-belt drives is about 93 percent over time (if not periodically re-tensioned).
Cogged belts can be used with the same pulleys as equivalently rated V-belts. They run cooler, last longer, and have an efficiency that is about 2 percent higher than that of standard V-belts.
Synchronous belts are toothed and require the installation of mating toothed-drive sprockets. They offer an efficiency of about 98 percent over a wide load range, require less maintenance and re-tensioning, and run slip free.
Check your compressed air system for connection, hose, and seal leaks, which can substantially increase run time. Leaks waste energy and reduce equipment life. A compressor system specialist can perform a test that can detect even very small, silent leaks.
Refrigeration equipment typically uses conventional, low-efficiency, shaded pole motors. When shopping for new units, look for refrigeration equipment with energy-efficient motors, such as split capacitor or electronically commutated motors. If you do not have plans to replace the refrigeration equipment anytime soon, consider replacing the shaded pole motors with more energy-efficient ones. Since refrigeration equipment operates 24 hours a day, your energy savings from this improvement can be substantial.
Dirty heat exchanger coils can significantly affect the efficiency of your refrigeration equipment. Over time, these coils become clogged with dirt and dust, making the compressor work harder and consume more energy. Try to make annual cleaning of refrigeration coils part of your regular maintenance schedule.
Cleaning dirty refrigeration coils can save 25 percent in operation costs, and helps prevent early compressor failure. The dust build-up acts as an insulator, causing the refrigerator to work harder to keep food cool. The coils can be kept clean by using either a vacuum or a dust broom. Consult the owner's manual for specific cleaning instructions.
For many years, chillers used 1 to 1.5 kW per ton of cooling. However, chillers are now available that use only 0.48 to 0.8 kW per ton of cooling and contain refrigerants that do not damage the ozone layer. These high efficiency units are cost effective replacements for older chillers that are near the end of their useful lives, or even newer chillers that operate for most of the year. A chiller with a SEER of 15 — or its kW per ton approximate equivalent — can provide major savings on your cooling costs.
Most chillers can operate down to 25 percent or even 15 percent of their rated capacity. However, their operating efficiency decreases significantly at these lower capacities. This means that cooling can be very inefficient in the spring and fall, when cooling loads are usually small.
This problem can be corrected by installing a variable speed drive on the chiller compressor motor. For chillers that are often run at part load, the savings can be significant. Variable speed drives regulate the frequency and voltage applied to a motor to control its speed and save it from unnecessary work, thus saving energy dollars.
Contact an air conditioning professional to evaluate the options applicable for your specific installation.
By raising the thermostat setting during the summer just one degree, you could save up to 5 percent on your cooling costs. Keeping the daytime temperature up near the recommended 78 degrees will keep costs down. Additionally, you could turn the thermostat to 85 degrees or shut the HVAC system off when the building is not occupied. You also can:
Air conditioning systems typically lose one to two percent in efficiency for every year that passes without proper maintenance. This can lead to steady increases in your cooling costs. Proper maintenance should be performed at least once a year and should include:
You should consult the owner's manual for proper maintenance of your particular system.
Consider reducing the use of your cooling system during hours that the building is unoccupied. The savings can be substantial. For example, setting the thermostat up to 90°F during the summer both at night and when the facility is not used could reduce your annual cooling costs by 10 to 15 percent.
Dirty and clogged air filters result block the flow of conditioned air and are the most common source of air conditioning service calls.
Consider reducing the use of your heating system during hours that the building is unoccupied. The savings can be substantial. For example, setting the thermostat back to 50°F in winters at night and when the facility is not used could reduce your annual heating costs by 10 to 15 percent.
Select control equipment that is compatible with your existing system. Contact your electrician or heating contractor for installation.
Unless building codes demand a higher hot water temperature, try setting the thermostat on your water heater to 120°F. This will reduce your water heater's energy use and you won't even notice the difference. Also, consider that there is a chance of accidental scalding from higher temperatures. By lowering the temperature to 120°F, you greatly decrease this risk.
Water heaters are usually controlled only by temperature. When the temperature of the water in the storage tank drops below its set-point, the heater turns on until the water exceeds the set-point, even if the water is not used. Install a time clock to shut down the heater at close-of-business and to restart the unit to warm up just before hot water is again needed. A time clock can save unnecessary heating costs that include stand by losses (heat that is lost through the walls of the storage tank).
An electric heat pump water heater presents a good opportunity for energy savings. Heat pump water heaters are extremely efficient alternatives to electric resistance style water heaters, often saving as much as 55 to 60 percent of water heating costs.
If copy machines or computers are not being used for extended periods of time, such as during lunch breaks or meetings, then some or all of the equipment can be turned off.
You can turn off your computer's display monitor and printer while leaving the main computer CPU on without any adverse effects on the equipment. This typically saves up to 60 percent of the operating costs of the whole computer system.
Be sure to turn off any equipment that is not used overnight, on weekends or during hours that the building is unoccupied. Assign an employee to the task, and/or post suitable reminder signage on the equipment.
Retrofitting fixtures with T-8 lamps and electronic ballasts can reduce their electricity use by 30 to 40 percent, depending upon the configuration of the lamps. T-8 lamps and electronic ballasts also offer better color rendering characteristics, eliminate most light "flicker," and generate less heat than T-12 lamps. The reduction in heat also can provide significant savings in cooling costs.
Replace indoor lighting fixtures using incandescent lamps with compact fluorescents, which consume 60 to 70 percent less energy and last about seven times as long as standard incandescent lamps.
When you replace your incandescent bulb with a compact fluorescent lamp (CFL), be sure to use a CFL that provides adequate light. A 15-watt CFL is usually appropriate for replacing incandescents up to about 60 watts. Use a 23-watt CFL for replacements up to 90 watts. For incandescent lamps over 90 watts, try a 28-watt CFL.
Considerable energy savings can be achieved by using high intensity discharge (HID) fixtures for outdoor lighting. High pressure sodium lamps (which have a golden color) and metal halide lamps (which appear bluish white) offer significant energy savings over standard incandescent lamps. As an example, consider that a 32-watt metal halide lamp can replace an incandescent bulb in the range of 100 to 150 watts, thus saving over 50 percent in outdoor lighting costs.
You can replace mercury vapor lamps with metal halide lamps using a ballast retrofit kit or a new fixture. A 100-watt metal halide lamp typically replaces a 175-watt mercury vapor bulb, thereby saving roughly 40 percent in outdoor lighting costs. Costs and savings will vary at your facility based on the specific wattages and usage of light fixtures (we have estimated that outdoor lights are used 8 hours per day).
Buildings typically use incandescent lamps in their exit signs. Incandescent exit signs typically use two 20-watt lamps. While the wattage is not very high, these fixtures are on 24 hours a day. You can replace these incandescent signs with more energy-efficient alternatives, such as compact fluorescent lamps, light emitting diode (LED) units, or electroluminescent (EL) signs. Retrofit kits with either two 7-watt fluorescent lamps or a 2-watt LED unit produce light equivalent to the incandescent lamps. While LED lights are initially more expensive, they can last up to 80 years, reducing inventory and maintenance costs.
Task lights, such as desk lamps, provide light where needed and allow you to decrease the amount of background light. Often, task lights use incandescent lamps. By replacing the incandescent lamps with compact fluorescents, you typically reduce energy consumption by 60 to 70 percent. In addition, heightening light levels in specific areas can reduce the need for ceiling fixtures and prevent eyestrain caused by overhead lights reflecting on computer monitors.
If your facility has access to daylight, consider using a daylight dimmable electronic ballast and a photo-eye sensing control system to utilize daylight in peripheral areas of your business. These sensors and ballasts measure ambient daylight and modify the light levels accordingly. You can also take advantage of daylight by manually turning off lights when there is ample daylight in the workspace.