Compressed air is used in many different industries. From refrigerator manufacturers to toy makers, companies around the world depend
on compressed air to produce products. It's so important that many consider it a utility as significant as electricity, water or natural gas.
Unfortunately, compressed air is also an expensive utility to produce. Many businesses spend tens of thousands of dollars generating compressed air. And lots of this air goes unused. In fact, we found nearly half of all compressed air is wasted.
With decades of experience designing energy-efficient air compressors, we understand the true cost of compressed air. We also know the potential savings are tremendous. In this article, you'll learn how to calculate the costs of compressed air- and how to cut them back.
Purchasing an air compressor is one of the biggest upfront costs. The price of an air compressor can vary depending on whether you're looking for a rotary screw compressor or a reciprocating/piston compressor. How you dry and purify air can also affect the price of an air compressor.
Along with equipment, consider the cost of installation. If your building needs retrofitting to accommodate the new compressor, factor this in.
If you're purchasing a new air compressor, you should include any rebates into the price. Many Quincy Compressors are eligible for energy efficiency rebates, which can bring down the cost of equipment.
Maintenance and repairs make up about 12 percent of an air compressor's lifetime cost, according to Energy Star data. These expenses include labor and replacement materials. You may also have costs from project delays if repairs are needed at a critical time.
Regular inspections and maintenance can decrease repairs. Set up an inspection schedule, and stick to it. It's much easier to prevent damage than it is to repair it. In addition, you'll be able to find and make repairs when the damage is minor. This can help you avoid more expensive and time-consuming damage down the road.
Some parts of a compressor are more susceptible to damage than others. Common problems include air leaks and damaged cylinders, rings, and bearings.
Components that are likely to develop leaks include:
Open condensate traps and shut-off valves
Fittings, couplings, tubes, and hoses
Joints on pipes, thread sealants, and disconnects
You can reduce the likelihood of damaged rings, cylinders, and bearings by regularly lubricating your equipment. Choose a suitable oil to lubricate air lines, bearings, and screws. Keeping lubricant clean, applying the correct amount, and regularly lubricating components can prevent many repairs.
Believe it or not, operating a compressor is usually more expensive than purchasing one. Energy Star says on average, 76 percent of the lifetime cost of an air compressor is electricity. In many businesses, compressed air is one of the most expensive utilities. Over 10 years of operating, a typical industrial air compressor can accumulate up to $800,000 in electricity costs.
Many factors impact the cost of compressed air. How long you run your air compressor and the cost of electricity in your area both can drive up cost. Technical specifications can also affect the cost of electricity. Energy-efficient air compressors cost less to operate than conventional compressors.
Because the cost of compressed air can be significant, Quincy Compressors offers a free walkthrough to establish a baseline of efficiency, otherwise known as EQ. The EQ rating can help you determine what the cost of operating a compressor will be.
Most air compressors cycle on and off throughout the day. While the compressor is cycling on, it draws power. Use a clock or a stopwatch to figure out how long the compressor runs each day. For many businesses, an air compressor's use differs by day. You can get a more accurate estimate by averaging the compressor's use over a week. To do this, track your usage for seven days and divide the sum by seven.
Your air compressor should have a wattage rating stamped on its nameplate. Multiply this wattage by the type of current needed to operate it. Many smaller compressors operate on a standard household current, which is llO volts. Larger air compressors may need 220- volt current.
Example: 15 amp air compressor X llO volts= 1,650 watts per hour
You will need to know how many kilowatt-hours the compressor uses to determine the energy cost. To find kilowatt-hours, multiply the watts per hour by the total amount of time the compressor runs for. Then divide this number by 1,000.
Example: 1,650 watts per hour X 3 hours= 4,950 watt hours
4,950 / 1000 = 4.95 kilowatt hours
So a 15-amp air compressor that runs for three hours will use 4.95 kilowatt-hours of electricity.
Most utilities charge by the kilowatt-hour. This means that you will need to multiply the total kilowatt-hours used by the electricity rate per kilowatt-hours. If your utility company uses tiered rates, you may want to use the average rate. This will give you a more accurate estimate than selecting the lowest rate.
Example: 4.95 kilowatt-hours X 15 cents per kilowatt hour= 74 cents for 3 hours of use
Luckily, there are many ways to reduce the costs of compressed air. Choosing the right air compressor can reduce your costs by approximately 45 percent. Today there are many energy-efficient compressors on the market.
Here are specific techniques you can use to save energy on compressed air.
Many modern air compressors offer better controls and storage than previous generations. If you're in the market for a new compressor, look for energy-efficient flow control and storage systems.
Flow Control: Nearly half of compressed air is wasted. Flow control tools that can sense downstream pressure and react to small changes can reduce compressed air waste.
Storage: Higher storage capacity means a compressor will need to run less often. If you use a lot of compressed air, you may want to consider increasing the storage capacity. In an efficiency study of Mega Brand, we recommended they increase their storage from 400 gallons to 1,560 gallons. That saved them $22,015 a year in compressed air costs.
Air compressors regularly cycle on and off to maintain the chosen pressure. Even minimal air leaks can cause your compressor to cycle on regularly. Compressors that are on constantly can use a significant amount of electricity. Many businesses leave compressors on during weekends and after hours. If you don't use your compressor during these times, turn it off. By turning it off when it's not in use, you can reduce your electric bills by up to 20 percent.
Although it's tempting to raise the pressure to compensate for air leaks or clogged filters, you will spend more on electricity if you do so. Each additional 10 sig requires approximately 5% more energy to produce. If you don't need the additional pressure, don't use it.
Changing your filter regularly can help reduce the electricity your air compressor uses. Clogged or dirty filters cause an air compressor's motor to work harder to provide the appropriate psi, which results in a higher electric bill.
Regular filter cleaning can also reduce the cost of maintenance and the likelihood of air leaks. Filters are responsible for removing dust and particles from the air. If these particles get into the compressor pipes, they can quickly corrode the pipes and cause air leaks.
Check compressor pipes regularly for any debris to make sure your filters are performing. If there is dust, dirt or sludge inside of the compressed air pipes, your filters are not doing their job. Replacing these filters immediately will reduce the likelihood of expensive repairs.
Regularly surveying for leaks can reduce energy use This can equate to five to ten thousand dollars a day in big companies. A successful leak audit requires three elements:
Knowledge: Ensure technicians understand the compressor's technical specifications and how to inspect the equipment.
Planning: Plan a regular time to inspect air compressors for leaks. If necessary, break up the inspection so it doesn't interfere with regular work. Tag and take pictures of any leaks for repair.
Follow through: Survey equipment again to make sure all tagged leaks have been repaired.
If this is the first time you've conducted a leak audit, you may have found many air leaks. This can easily overburden an alreadyover-worked maintenance staff. Prioritize any air leaks you find by size. Larger holes mean your equipment will need more power to maintain air pressure. These should be repaired first. Add a note that includes the priority level of any repairs to be made when you find new leaks.
Regular maintenance reduces the likelihood of large, time-consuming repairs. It can also prevent smaller air leaks from forming. Check pipes, seals, and bearings regularly for corrosion and particulates.
Make sure compressor components are operating within their optimum range. Periodically clean the water jackets and pipes that help to maintain the temperature of the air compressor. If a compressor gets too hot, costly repairs and breakdowns are more likely. If the compressor is air-cooled, check to make sure fins are not clogged with dirt.
You can reduce the amount of energy your compressor needs by optimizing the pipes that deliver air. For instance, you can increase air pressure by reducing the pipe size. This often means you can operate your compressor at a lower psi.
Choosing smaller pipes is one of the most effective ways to increase air pressure. Replacing a 3-inch diameter pipe with a 2-inch diameter pipe will increase air pressure by approximately 50 percent. You may also want to consider whether you can shorten the distance between the compressor and the air end.
Some businesses choose to use the heat from air compressors for heating their building. By recirculating this air, you'll reduce the need for additional heating.
To make this effective, you'll need to have ducting installed connecting the compressor to the area you will heat. Reclaiming compressor air for heating is most effective if your compressor is air-cooled. Some businesses do reclaim water from water-cooled compressors for other uses as well.