When using rotary screw compressors, boosters and blowers, a considerable portion of the energy generated is lost as heat. In these times of ever-scarcer resources and high energy prices, this is an issue that clearly needs to be addressed. There is however an answer: Thanks to innovative heat recovery systems, this heat can be recovered and put to good use. In our blog post, we show you the benefits of utilising exhaust heat.
Heat recovery – The right decision
Rotary screw compressors, boosters and blowers convert almost 100% of the electrical drive energy supplied to them into heat. The heat flow diagram, using the example of a fluid-injected rotary screw compressor, shows how this energy is distributed within the compressor and how much of it can be utilised. Approximately 96% of the energy input can be recovered for reuse, whilst 2% remains in the compressed air and another 2% is dissipated into the ambient surroundings.
* approximate figures
(1) | 100% | total electrical consumption
(2) | approx. 5 % | exhaust heat from the drive motor
(3) | approx. 15 % | reusable heat energy recoverable through compressed air cooling
(4) | approx. 76 % | reusable heat energy recoverable through fluid cooling
(5) | approx. 96 % | usable heat energy
(6) | approx. 2 % | of the heat energy from the compressor package radiates into the ambient surroundings
(7) | approx. 2 % | heat energy remains in the compressed air
(8) | approx. 4 % | unusable heat energy
Where does the energy in compressed air come from? The answer is simple: During the compression process, the supplied electrical drive energy is converted into compressed air and heat. The compressor charges the air it intakes with an energy potential that corresponds to approximately 25% of the compressor’s electrical power consumption. The resulting heat energy is available, depending on the compressor design, as either hot air or hot water.
When does the compressed air energy become usable? This energy becomes usable when the compressed air expands again at its point of consumption and, in so doing, absorbs heat energy from the ambient surroundings. Of course, the amount of energy available for reuse depends on the pressure and leakage losses within the compressed air system.
Heat recovery systems – Flexible for every need
To fully harness the potential of the generated heat energy, rotary screw compressors, boosters, and blowers can be equipped with modern heat recovery systems. These significantly reduce primary energy consumption for heating or hot water production.
KAESER offers the optimal solution for every need.
Hot air for space heating: Air-cooled rotary screw compressors, boosters and blowers from KAESER are ideal as complete systems to aid heat recovery for space heating and other hot air applications. Direct use of recyclable heat via an exhaust air ducting system enables up to 96 % of the total energy input to be recovered and reused.
Hot water production: KAESER offers heat recovery systems with special heat exchangers for applications requiring hot water. This allows fluid-injected rotary screw compressors, depending on the design, to produce process, service, and drinking water heated up to 85°C. The indirect use of recyclable heat via heat exchanger systems can utilise up to 76% of the electrical power provided to the compressed air supply.
With our KAESER Energy Saving System (KESS), it is possible to precisely calculate the heat recoverable through hot water, depending on the operating behaviour of the compressors. Your benefit: Once the measurement process is complete, you will receive your individual potential for heat recovery—expressed in kWh and euros. This provides you with a clear, detailed view of your savings in black and white.
This is where heat recovery counts:
- Feed into central heating systems
- Hot water for sanitary equipment
- Drying and sterilisation processes
- Utility water for the food and beverage industry
- Service water for the textile industry
- Process water for the manufacturing industry
Heat recovery systems can be used in various sectors to improve energy efficiency and reduce costs. A common application is utilising exhaust heat from the compressors to heat buildings or to heat water in industrial processes. These systems can also be used in the food and beverage industry to generate process heat or to preheat air in drying systems.
Additionally, heat recovery systems can be used in the chemical industry, mining industry, textile industry, and many other sectors to boost energy efficiency and minimise environmental impact.
The benefits at a glance
Energy efficiency:
You can significantly reduce your energy costs by recovering recyclable heat. The recovered heat can be used to heat spaces, to heat water, or to support industrial processes. You are therefore able to use your energy twice and save money at the same time.
Sustainability:
By utilising the recyclable heat from your compressed air supply, you significantly reduce CO2 emissions. Heat recovery actively contributes to climate protection and helps your company operate more sustainably.
Needs-oriented:
Depending on your specific requirements, different temperature levels and water quantities can be selected, allowing you to perfectly tailor the system to your individual needs.
Flexibility:
Heat recovery systems from KAESER can be adapted to almost any compressor. Whether you already have an existing system or wish to install a new one, our innovative technology can be integrated seamlessly.
Funding opportunities:
Government subsidy programmes are available to support energy-efficiency measures. Find out about potential funding opportunities and start benefiting today.