Air compressors are efficient and cost effective, which is why they are common in workshops, manufacturing, and processing. They are so common that a regularly quoted statistic is that they account for around 12% of the UK’s industrial energy usage. However, as much as 90% of that energy is wasted as heat.
Heat is an unavoidable by-product of compressed air. Generally, it is dissipated by a combination of cooling systems and natural cooling as the air moves through your compressed air system. However, heat recovery can recover as much as 94% of that heat, helping you cut your energy bills and shrink your environmental impact.
How air compressor heat recovery works
When producing compressed air, a large portion of the electrical energy used is converted into heat. Without a recovery system, this heat is typically lost through cooling air or expelled as warm air into the atmosphere.
A compressed air heat recovery system captures that heat from the compressor and repurposes it. In oil-lubricated compressors, the heat from the oil circuit is transferred to water using a heat exchanger such as a PTG heat exchanger. This water can then be used in a hot water system or for supplying hot process water. In air-cooled systems, the hot air from an air-cooled compressor can be redirected for ambient air heating in workspaces.
Heat can also be recovered from water-cooled systems using water-to-water heat exchangers. These solutions form part of wider industrial waste heat recovery technologies and can provide significant energy savings when compared to traditional fuel-based heating.
Recovery efficiency usually ranges from 70 to 94 percent, depending on the system. Atlas Copco UK and other leading manufacturers note that compressor heat recovery systems can help reduce energy consumption, lower energy costs, and significantly cut carbon emissions and energy waste.
The energy recovery process is straightforward to install, does not interfere with performance, and allows you to calculate the usable heating energy using a heat recovery calculator. Whether you are heating workspaces, water supplies, or process systems, these solutions allow you to recover waste heat effectively and reduce total energy costs in industrial settings.
How can air heat recovery be used?
Just like your air compressor, heat recovery can be versatile.
- Space heating: perhaps the most direct heat recovery method is ducting the hot air to warm your workshops, saving on heating system costs.
- Water heating: the water from a heat exchanger can reach 90º. It can be used in washrooms and staff facilities, to feed boilers, or even in any processes that need heated water.
- Operational processes: the heat can be used in any applications that need heat, like food processing, laundry, paint booths, or even for simple drying.
Systems can also be designed to switch uses, allowing you to save on heating in winter and hot water in summer.
Heat recovery components
Regardless of your compressor type, you can benefit from heat recovery. Most modern compressors can easily be adapted for heat recovery, and can even come with heat recovery components pre-installed. Retrofitting older compressors is also almost always possible.
- Oil-lubricated compressors use an oil circuit heat exchanger. These capture heat from the compressor’s oil loop.
- Water-to-water heat exchangers transfer the heat from water-cooled compressors. This means heated water can be used anywhere, without risk of contamination from the compressed air system.
- Ducting and louvres are used with air-cooled compressors. These help capture and redirect the warm exhaust air, allowing you to use it rather than being lost to the atmosphere.
The benefits of a heat recovery system
There are many reasons you should use heat recovery.
Energy efficiency
By recovering over 90% of the heat from your compressor, your compressed air system will be incredibly energy efficient.
Cost savings
Because you can use the recovered heat instead of generating that heat again, you can dramatically cut your energy costs. Depending on usage, you might find that heat recovery pays for itself in a year.
Environmental benefits
Increasing your energy efficiency and reducing your energy use helps the environment. It is estimated that air compressor heat recovery in the UK could save enough energy each year to power more than one and a half million houses.
Will you benefit from heat recovery?
Most businesses using air compressors can benefit from an air compressor heat recovery system. Since a lot of the electrical energy used in air compression is converted into compression heat, there is substantial potential to reuse this energy instead of letting it go to waste.
Recovery systems can heat water for staff facilities, cleaning or production processes, or redirect warm air for space heating. Sites that generate a lot of heat from air compressors, such as manufacturing, food processing or workshops, often see the greatest savings, especially when heat recovery is compared to fuel or boiler-based systems.
Even older systems, which may be less efficient, are well suited to retrofitting. Recovery system design is flexible and can be tailored for both air-cooled and water-cooled units. Whether heat is transferred using hot air heat recovery or through water-based heat exchangers, the goal remains to reduce the energy required elsewhere.
A heat recovery system allows you to significantly cut carbon emissions and energy consumption while reducing total energy costs for industrial applications. With tools like a heat recovery calculator, it is easy to assess your potential savings and determine what is best suited to your setup.
Can your system use heat recovery?
It is almost always possible to retrofit heat recovery to a compressed air system. Indeed, older systems, which may be less efficient, usually bring the biggest savings through heat recovery. And, although it is easier to include heat recovery at installation, retrofitting can often be completed with minimal disruption, and sometimes with no downtime.
If you want to benefit from heat recovery, we are always happy to advise on the type suitable for your compressors, as well as the possible uses and savings it could offer.
Our engineers can also help you with installation, taking care of design, including the necessary components, and ensuring the required safety systems, like pressure reliefs and temperature controls, are in place.
Some common myths
We frequently find people have resisted heat recovery because of some common misunderstandings about heat recovery.
Myth: It is only for winter
Heat recovery works all year round. Your compressor generates heat regardless of the weather. How you use that heat at different times of the year is likely to change.
Myth: It is only for 24-hour operations
Heat recovery works whenever your compressor is on. You will still benefit because it supplements other systems, like your heating or hot water, although the return on your investment will take longer.
Myth: It will affect performance
Heat recovery can have a positive impact on performance. By helping your compressor’s cooling system remove heat, heat recovery can help your compressor continue to work at optimum levels for longer.
Getting started with heat recovery
Getting started with heat recovery could not be easier. Our team has helped hundreds of businesses design, install, and maintain their heat recovery systems, saving them money, helping the environment, and, just as important, keeping them warm!
Just contact Design Air. We can offer you a heat recovery assessment, taking you through the type of installation we can offer, the impact it will have, and even calculating the savings you can expect from it.
FAQ
What happens to the heat generated from air compressors, and can it be reused?
The heat generated during compression is typically lost without a recovery system in place. However, an air compressor heat recovery system can capture that heat and transfer it for practical use, such as space heating or water heating. By recovering the heat that would otherwise be wasted, businesses can reduce energy consumption and improve efficiency.
How can a heat recovery system reduce total energy costs for industrial sites
A well-designed waste energy recovery system allows heat to be transferred from the compressor’s operation to where it is needed. Recovery systems can heat water or air, reducing the energy required from traditional sources like gas or electricity. This often leads to lower energy bills, especially when heat recovery is compared to fuel oil systems.
Are heat recovery systems compatible with older or existing compressors
Yes, many recovery systems are designed to be retrofitted to existing units, including air-cooled models and Atlas Copco compressors. Whether using hot air heat recovery or water-based exchangers like steel plate heat systems, most of the heat generated from air compressors is recoverable. A system can be tailored to suit the application and site requirements.
