Energy Recovery in Air Compressor Systems

Compressed air systems produce a significant amount of wasted energy every year. As compressors operate, they generate substantial heat, which is often simply vented into the atmosphere, representing a lost opportunity for heating uses.

Fortunately, energy recovery offers a powerful solution. By capturing and repurposing this wasted heat, you can dramatically reduce your energy costs and minimise your environmental footprint. Energy recovery systems transform your compressed air system from a simple energy consumer into a valuable source of reusable heat, creating a more sustainable and efficient operation.

This guide will delve into the ins and outs of air compressor energy recovery, exploring the technology behind it, the benefits it offers, and how you can implement it to unlock significant savings and enhance the sustainability of your business.

Understanding Air Compressors and Energy Production

In the industrial arena, around a tenth of all electrical energy supply is used to power compressed air systems and around 94% of all that energy turns into heat. The heat energy supplied is generated to power the compressed air system, but what’s frustrating is that the heat generated then has to be cooled down using chillers and cooling fans!

It’s clear that this method of heating and cooling is not efficient, causes hikes in energy bills, and the company’s carbon emissions! Rather than putting up with this, finding a new way to deal with the excess heat in heat recovery systems can offer a better way to manage the warm air, and offers a simple way to reduce heating costs.

How Energy Recovery Systems Work

Energy recovery systems capture the heat generated from your compressed air systems and repurpose it for various uses, such as heating water or spaces. This recovered energy can be utilised efficiently through water-cooled compressors or air-cooled compressors. For example, in water-cooled systems, heat from the compressor is transferred to water via a heat exchanger, turning waste heat into usable energy for industrial processes or facility heating.

Modern systems can recover up to 90% of the energy supplied to the compressor, especially in rotary screw compressors. Compressor heat recovery is optimised with variable speed drives (VSDs), which adjust motor speeds based on demand, maximising energy recovery potential. Digital controls ensure that recovered energy is best utilised based on real-time compressor loads, ensuring available heat is always efficiently harnessed.

By capturing waste energy via hot air or hot water, businesses reduce operational costs, improve energy efficiency, and enhance sustainability, transforming a compressed air installation into a source of valuable heat energy.

Types of Energy Recovery Systems

When it comes to heat recovery systems, there are a number of options to choose from, including:

• Air-Cooled Lubricant Injected Rotary Screw Compressors
  
• Water-Cooled Lubricant Injected Compressors
  
• Water-Cooled Oil-Free Compressors
  
• Engine Driven Compressors

Choosing the right solution for your needs depends on your compressed air system, the amount of waste heat you are producing as well as your budget, how much hot water is required, and the stable heat energy demand you have in your industrial compressed air operation.

The Main Benefits of Energy Recovery Systems

Are you considering a waste heat recovery system for your air compressor? You can look forward to many benefits when you decide to invest. Some of the main benefits of heat recovery systems include:

• Energy Savings
  
• Reduced CO2 Emissions
  
• Increases Operational Sustainability

Each of these benefits works hard to help you reduce the wasted excess heat generated from your compressed air system hot air, and convert it in the heat exchanger so that you can enjoy hot water when it is required, without needing to increase the energy required.

Things to add in this section:

• Highlight the environmental benefits, such as reduced CO2 emissions, particularly in applications like electric car battery production which demand sustainable manufacturing practices​​.
  
• Emphasize cost savings through reduced energy consumption and operational expenses, stressing the lower life cycle costs and minimized CO2 emissions​​.

The Main Benefits of Energy Recovery Systems

Investing in an energy recovery system for your air compressor is a combination of financial and environmental advantages. By harnessing wasted heat, you unlock significant savings and contribute to a more sustainable operation.

Energy Savings: Turning Wasted Heat into Reduced Costs

Energy recovery systems directly translate to lower energy bills. By capturing and repurposing the heat generated by your air compressor, you reduce your reliance on traditional heating sources for your facility, process water, or domestic hot water. This can lead to substantial cost savings, especially in industries that rely heavily on compressed air, where the amount of wasted heat is significant.

Reduced CO2 Emissions: A Sustainable Step Forward

Energy recovery systems align perfectly with this goal by significantly reducing your carbon footprint. By lowering your energy consumption, you directly decrease greenhouse gas emissions associated with traditional energy production.

This is particularly relevant in industries like electric car battery production, where sustainable manufacturing practices are essential to offset the environmental impact of traditional vehicles. By implementing energy recovery, you not only reduce your operational costs but also demonstrate a commitment to sustainable manufacturing and a greener future.

Environment forward practises like energy recovery systems also let you get government rebates and incentives. 

Increased Operational Sustainability: Long-Term Benefits

Energy recovery contributes to a more sustainable operation in multiple ways:

• Lower Life Cycle Costs: By reducing energy consumption and minimising wear on your heating systems, you extend the lifespan of your equipment, resulting in lower maintenance costs and a longer return on your investment.
  
• Enhanced Brand Image: Adopting sustainable practices enhances your brand reputation, demonstrating your commitment to environmental responsibility.

Energy recovery systems are a win-win solution, offering both immediate cost savings and long-term benefits for your business and the environment.

Practical Applications of Energy Recovery

Whether you have oil-lubricated compressors or a different air compressor model, there are several practical applications for the energy you have recovered. In fact, the recovered energy demand is sure to impress when you utilise it for one of the following uses:

Space Heating Systems

Keeping your premises warm can be expensive, especially during the colder months. By recovering heat, you can then use it to lower your heating bill and increase the ambient temperature whenever needed. This cost-efficient model will ensure that you can heat your location when needed, or even preheat the area before work starts for the day.

Water Heating Costs

Heating water takes up a lot of available energy but is essential for a wide range of industrial processes. When you create hot water with energy recovery, you can enjoy pre-heated water whenever you need it cost-efficiently. When you don’t need all the energy on offer, you can use the cooling system to drop the thermal energy temperature required to a level that works for you.

Industrial Process Solutions

It’s not just heating and hot water that can be produced through recovered energy, but also a range of industrial processes can be supported with the supplement energy supplied. From a range of chemical processes to cutting, separation, moulding and more, you can look forward to your input energy being converted in a way that works for your industrial needs.

Factors That Affect Energy Recovery

As with any process, there are a variety of factors that can impact your energy recovery processes and usage. Take a look at some of the most significant now:

Seasonal Variable Load

Seasonal changes can significantly impact energy recovery, especially when your hot water or space heating bill traditionally goes up in the colder months and reduces when it is warm.

During each season you will find that your need for specific functions, such as hot water, varies and being aware of what you may need your heat exchanger to do is a great way to plan for all eventualities.

Remember that your compressed air systems will probably be in use all year round, so take time to carefully consider how to utilise the heat recovery process to work best for you.

Compressed Air System Utilisation

When you want to save money on your cooling water system, or make sufficient quantities of heat for hot water system support, you must first consider the compressed air compressor you are using.

As the compression process works to remove heat when compressing air using a heat exchanger or a compression heat fan, you must set your system to recover as much electricity as possible.

To utilise your total industrial electricity consumption in a way that can be redirected to the facility’s heating system or hot water system, it’s important to recover at least 90% of the electricity for the very best outcomes.

Challenges and Considerations for Energy Recovery Systems

While energy recovery from your compressed air system offers many advantages, there are important challenges to consider.

System Integration

Incorporating an energy recovery system into an existing compressed air installation can be complex. Proper design is essential to handle fluctuating compressor loads and ensure that the available energy is always utilised efficiently.

Initial Costs

The upfront investment for energy recovery can be substantial, but the payback is usually quick, often within a few years, thanks to reduced energy costs and recovered heat energy.

Compressor Efficiency

Recovery systems may affect compressed air production, especially if ducting the air or cooling creates pressure drops or resistance. It’s important to ensure that the system is designed to avoid compromising efficiency.

Maintenance

Regular maintenance of the water heat exchanger and other components is essential. If ducting the air or the compressor becomes clogged, it could reduce system efficiency. The compressor must be kept clean and free of obstructions for optimal performance.

Seasonal Load Variability

The quantity of recovered energy will vary based on seasonal demands, with recovered heat energy better suited for space heating in colder months. In warmer months, it may be better utilised to supplement energy for hot water production.

Monitoring

Advanced control systems, such as those in Atlas Copco compressors, can help track recovered energy and optimise performance. Without proper monitoring, energy recovery potential may not be fully realised.

By addressing these challenges, businesses can ensure that their energy recovery from compressed air systems operates efficiently and delivers long-term benefits.

Modern Air Compressors and Heat Recovery

As compressed air solutions from companies like Atlas Copco work hard to find new ways to save energy, you will find that many air compressors now feature heat recovery as part of their overall design. This means built-in heat exchanger options and better access to heat solutions that can save energy, lower costs, and redirect electricity to be used in other applications.

Modern air compressors are no longer just about delivering pressurised air—they’re about doing so with maximum efficiency and minimal environmental impact. Leading manufacturers like Atlas Copco are integrating energy recovery solutions directly into their compressor designs, ushering in a new era of energy-conscious operations.

These advancements go beyond simply adding a heat exchanger. Innovative technologies are enhancing energy recovery efficiency and unlocking even greater potential for savings:

• Variable Speed Drives (VSDs): VSDs allow compressors to adjust their motor speed based on demand, reducing energy consumption during periods of lower air requirement. This, in turn, optimises the amount of heat available for recovery, maximising the potential for energy savings.
  
• Advanced Control Systems: Intelligent control systems monitor and regulate compressor operation in real time, adjusting parameters to optimise both air delivery and heat recovery efficiency. This ensures that the system operates at peak performance while maximising energy savings.

Looking Ahead: The Future of Sustainable Compressed Air

The future of compressor technology holds exciting possibilities for further advancements in energy recovery:

• Smart Systems and Predictive Analytics: Integrated sensors and data analytics will enable compressors to anticipate demand and optimise energy recovery proactively. This will lead to even greater efficiency and reduced waste.
  
• Waste Heat to Power: Researchers are exploring innovative ways to convert waste heat directly into electricity, potentially creating self-powering or even energy-positive compressor systems.

As sustainability becomes increasingly critical, the role of energy recovery in compressed air systems will only continue to grow. Modern compressors, equipped with innovative technologies, are poised to lead the way towards a more energy-efficient and environmentally responsible future.

Let Control Gear Support Your Energy Recovery Needs

It’s clear that investing in a heat recovery system is a great way to utilise recovered waste heat energy, save energy, and reduce your overall energy costs. However, knowing how to proceed can be difficult, but Control Gear are here to help.

Get in touch today to find out more about how to conduct an audit of your energy consumed so that you can identify the key areas for energy-efficient recovery!

Frequently Asked Questions

1. How much heat can be recovered from a compressed air system?

A significant amount of heat can be recovered from a compressed air system – up to 90% of the energy supplied to the system during compression is converted into heat. This recovered heat energy can be repurposed for various applications, such as space heating or water heating, improving the system’s overall efficiency.

2. Does a variable load affect the efficiency of energy recovery?

Yes, if the compressor has a variable load, the amount of waste energy recovered may fluctuate. However, advanced systems are designed to ensure that the available energy is always utilised efficiently, even when the compressor operates under varying loads, maximising the potential for heat recovery.

3. What is the typical return on investment for energy recovery systems?

The return is usually as short as a few years, depending on the compressor installation and the amount of waste heat recovered. By capturing waste heat via hot air or hot water, businesses can reduce their energy costs and offset the initial investment quickly.