Compressed Air
Bootcamp

Compressed air accounts for as much as 10% of industrial electricity consumption in the European Union and in some cases energy consumption due to compressed air systems can reach 25% of the total. These numbers are similar in all developed countries.

Compressed air leaks alone account for 25—30% of compressed air use in industrial compressed air systems.

The cheapest and fastest way to reduce the carbon (CO2) footprint of your industrial compressed air system is to reduce leakage.

The European Commission SAVE programme report, ‘Compressed Air Systems in the European Union’, estimates that by reducing air leaks, organizations can achieve as much as 42% of the total energy savings potential in industrial compressed air.

How is air compressed?

Air is compressed in two simple steps:

1. Air is trapped in a cylinder, tank, or similar container.
2. The space in that tank becomes smaller, which forces the air molecules closer together. The now compressed air remains trapped in this smaller space, waiting to expand again, until it’s used.
   
   

Why is compressed air hot?

Compressed air is hot because the air molecules are physically forced closer together during compression, which causes them to move quickly; this rapid molecule movement generates heat.

Hot air can be dangerous, and heat also increases the amount of water in the air stream, so most air compressor designs include aftercoolers to reduce the temperature of the compressed air in combination with separate dryers to lower moisture. The process of aftercooling and drying requires a lot of electricity on top of the compressor load.

FACT. Almost 95% of the heat generated by an industrial rotary screw compressor can be harnessed and put to other uses such as providing building heating or hot water, achieving considerable energy savings.

When used properly compressed air is completely safe. However, dabbling with compressed air or using it in inappropriate ways can be dangerous and even deadly.

Here are a few examples of the ways in which compressed air should not be used:

• Pointing air at an open wound as it can obstruct an artery and result in an embolism
• Cleaning your cloths or blowing dust around, as debris can fly into the eyes
• Blowing towards a colleague as a joke.
• Blowing into a mouth, as it may rupture the lungs
• Blowing into eyes may force them out of their sockets
• Blowing into ears can rupture the eardrums and cause brain damage

FACT Did you know that air guns – weapons which use compressed air to fire a projectile such as a bullet or lead shot – date back at least as far as the sixteenth century? An example of a bellows-driven mechanical airgun dating from 1580 can be seen in the Livrustkammaren Museum in Stockholm, Sweden.

Compressed air is clean, safe, simple and efficient as far as energy sources go. However, compressed air can be dangerous when used improperly or if air receiver tanks aren’t properly maintained. Therefore, operators should always follow the guidelines set by manufacturers. Standard protective equipment should always consist of glasses, gloves and ear protection. 

Never compromise on safety. Be sure to carry, wear and use the required safety equipment!

FACT. The world’s largest geared compressor rotor, with a first stage impeller measuring 1.8 meters, was engineered and tested by Siemens at its Duisburg, Germany, facility. The impeller was balanced at a speed of 3,970 rpm, with the outside diameter of the first stage impeller rotating at 1,350 km/h.

With less than 10 years to go, a global effort is underway to deliver the 2030 promise of the United Nations (UN) Sustainable Development Goals. According to the UN, progress is being made in many places but, overall, action to meet the Goals is not yet advancing at the speed or scale required.

Certifications like ISO 50001 are available for organizations to document that they monitor energy efficiency and address savings potentials in all areas of operation.

FACT. Carbon emissions from energy use are rising at the fastest rate since 2011.

Extreme weather is driving up demand for energy. Carbon emissions from global energy use jumped two per cent in 2018, according to BP’s annual world energy study. This was the fastest growth in seven years and is roughly the carbon equivalent to increasing the number of passenger cars worldwide by a third. The unusual number of hot and cold days in 2020 resulted in increased use of cooling and heating systems powered by natural gas and coal. The energy sector accounts for two-thirds of all carbon emissions.

Across the globe we are seeing an increasing demand for certifications like ISO 50001 which is the standard for helping organizations manage their energy performance. It also provides a framework of requirements for organizations to:

• Develop a policy for more efficient use of energy
• Fix targets and objectives to meet the policy
• Use data to better understand and make decisions about energy use
• Measure the results
• Review how well the policy works
• Continually improve energy management

Energy costs are by far the largest expense of owning and operating compressed air systems. If compressed air was free there would be no incentive to implement a leakage management project. However, as most companies are aware, compressed air is a very expensive “fourth utility” when evaluated on a per unit energy delivered basis.

What is the Return on Investment for repairs?

Leakage repair represents the fastest return on investment (ROI) in compressed air system projects. According to industry data, the typical ROI for compressed air system repairs and retrofits is 1 to 2 years.

However, the 7 000 leakage management projects that we have completed at Enersize demonstrate that ROI can be as quick as 3 to 9 months.

Leaks can be a significant source of wasted energy in an industrial compressed air system. A typical plant that has not focused on energy optimization of compressed air will on average have a leakage rate equal to 20-35% of total compressed air production capacity.

Even small leaks generate huge costs (Eurostat average EU energy industry pricing)

Audit compressed air needs  

Compressed air needs are defined by the air quality, quantity and level of pressure required by the end uses in your plant. Analysing needs will ensure that a compressed air system is configured properly so that a clean, dry and stable supply of compressed air can be delivered at minimal cost.

Detect leaks

The best way to detect leaks is to use an ultrasonic acoustic detector which can recognize high frequency hissing sounds associated with air leaks.

A leakage survey will help you find, grade and document leaks.

Repair leaks

Leaks are a significant source of lost energy in a compressed air system, often wasting as much as 25-30% of the compressor’s output.

Compressed air leaks can also contribute to problems with system operations, including fluctuating system pressure, excess compressor capacity or decreased service life and increased maintenance of supply equipment.  

A repair project will help you avoid losing money on wasted energy.

Monitor and maintain

A one time approach to fixing leaks is not good enough. Far better to incorporate a leak prevention program into your facility’s operations. It should include identification and tagging, tracking, repair, verification,and employee involvement. Set a reasonable target for cost effective leak reduction: 5-10% of total system flow is typical for industrial facilities.

A continuous monitoring and maintenance program will help you track the essential key performance indicators (KPIs) for your compressed air system and identify problem early.

For most organizations the journey towards excellence is a step-by-step process, from initial awareness of the state of the compressed air system, to becoming champions in energy excellence. Continuous monitoring to generate facts and data driven decisions is an important step to reaching maximum energy optimization of industrial compressed air.