AIR TO AIR HEAT EXCHANGER
An industrial air to air heat exchanger is a thermal exchanger designed to recover residual thermal energy by transferring heat between two completely separated air streams, while maintaining system tightness of approximately 99.9%.
BOIXAC air to air heat exchangers allow the recovery of energy contained in hot exhaust air or process air to preheat clean supply air, transforming an unavoidable energy loss into useful energy. This results in a direct and measurable improvement in the overall energy efficiency of the installation, reducing energy consumption, operating costs, and CO₂ emissions associated with the process.
Thanks to a cross-flow configuration optimized using thermal engineering criteria, these units can achieve thermal recovery efficiencies of up to 80%, positioning them among the solutions with the highest economic return in industrial energy efficiency.
When to choose an air-to-air heat exchanger
The air-to-air heat exchanger is particularly suitable when thermal energy recovery is required between two streams of clean or slightly contaminated air, while maintaining an almost complete separation between the flows.
In processes involving combustion fumes, solid particles or very high temperatures, or where 100% tightness must be ensured, it is advisable to choose an air-to-fume heat exchanger or another specific gas-to-gas system.
The correct selection of the heat exchanger mainly depends on the gas temperature, the level of contamination and the process requirements.
Operation of the air to air heat exchanger
The operation of an air to air heat exchanger is based on a controlled gas-to-gas heat transfer process, in which two air streams flow through independent channels separated by a heat exchange surface specifically designed to maximize heat transfer with minimal pressure drop.
The hot air releases part of its thermal energy.
The incoming cold air absorbs this energy.
There is no direct contact between air streams.
High system tightness is guaranteed.
This operating principle allows:
Recovery of energy from exhaust air or process air.
Complete separation between air streams.
Stable operation with large airflows.
Reduction of required power in heating, ventilation, or air conditioning systems.
BOIXAC air to air heat exchangers are easily integrated into existing installations such as industrial ventilation lines, dryers, furnaces, HVAC systems, or continuous processes, without compromising production continuity and adapting to the real operating conditions of each application.
Key advantages of air to air heat exchangers for industry
BOIXAC air to air heat exchangers are designed for continuous, energy-intensive industrial processes where operational stability and sustained performance are critical, delivering direct and measurable benefits:
Significant energy savings and reduced operating costs.
Reduction of CO₂ emissions and lower environmental impact.
Improved overall performance of the production process.
Increased industrial competitiveness.
Optimal integration with control and automation systems.
Typical industrial applications of air to air heat exchangers
BOIXAC air to air heat exchangers are particularly suitable for processes involving large air volumes and high temperatures, where other recovery systems are not viable:
Food industry: dryers, dehydration processes, thermal treatments.
Paper industry: heat recovery from hot air in ovens and dryers.
Chemical and pharmaceutical industry: energy recovery and thermal control of process air.
Agriculture and greenhouses: energy optimization of climate control systems.
Ceramics, foundries, and metallurgy: improved performance of furnaces and industrial heating processes.
Design, innovation and construction features
Modular and custom design
BOIXAC units are engineered with a modular design, using single or multiple cross-flow configurations defined from real process data, adapting dimensions, geometries, and air paths to each industrial project.
High-resistance materials
Designed to operate in demanding industrial environments, with material selection criteria based on temperature, corrosion, and service life, ensuring durability, mechanical stability, and operational reliability.
Accessible and efficient maintenance
Optionally, the units can incorporate automatic spray cleaning systems, as well as inspection and cleaning doors that facilitate preventive and corrective maintenance, minimizing unplanned downtime.
Energy efficiency and sustainability
With efficiencies of up to 80%, these systems typically achieve ROIs between 3 and 12 months, with a direct impact on the decarbonization of industrial processes.
Advanced tightness
Mechanical sealing systems ensure tightness levels of up to 99.9%, a critical condition in applications involving contaminated air or strict safety requirements.
Typical ROI
3-12 months
Efficiency
up to 80%
Warranty
2 years
Airtightness
up to 99%
FAQs
What is an air to air heat exchanger?
An air to air heat exchanger is an industrial exchanger that transfers thermal energy between two completely separated air streams, without mixing.
This type of equipment enables the recovery of heat contained in exhaust air or process air to preheat clean supply air, improving energy efficiency and reducing the overall energy consumption of the system.
What is the difference between an air to air heat exchanger and a gas to gas heat exchanger?
An air to air heat exchanger is manufactured using expanded tubes, providing tightness levels of approximately 99.9%, while a gas to gas heat exchanger is manufactured using welded tubes, achieving 100% tightness.
Although the physical principle is the same, the air to air heat exchanger is optimized for ventilation systems, process air, and industrial exhaust air. Its design accounts for large airflows, low pressure losses, and high tightness levels, which are critical factors in industrial applications with strict safety and efficiency requirements.
Is it suitable for exhaust air?
Yes, it is suitable for recovering heat from industrial exhaust air.
Air to air heat exchangers can operate with exhaust air provided that the design is adapted to the level of fouling, temperature, and gas composition. Depending on the process, BOIXAC selects materials, geometries, and construction solutions that ensure stable operation and controlled maintenance.
What energy efficiency can an air to air heat exchanger achieve?
An air to air heat exchanger can achieve thermal recovery efficiencies of up to 80%.
Actual performance depends on factors such as temperature difference between air streams, airflow rates, flow configuration, and operating conditions. In properly engineered industrial applications, these systems enable significant reductions in energy consumption and direct improvements in system ROI.
Can an air to air heat exchanger be custom designed?
Yes, air to air heat exchangers can be fully custom designed.
BOIXAC designs each exchanger according to airflow rates, temperatures, available space, and specific requirements of the industrial process. Custom design allows optimization of efficiency, seamless integration into existing installations, and reliable long-term operation.
What maintenance do air to air heat exchangers require?
Maintenance of an air to air heat exchanger is simple and accessible.
The units incorporate inspection doors that provide easy access to the heat exchange bundle for cleaning and preventive maintenance tasks. Depending on the application, automatic spray cleaning systems can be integrated, reducing downtime and operating costs.
What materials are commonly used in their construction?
Industrial air to air heat exchangers are commonly manufactured using carbon steels or stainless steels.
Material selection depends on operating temperature, environmental corrosion, and air or gas composition. The most commonly used materials include carbon steel and stainless steels AISI 304, AISI 316, AISI 309, and AISI 310, ensuring mechanical strength, durability, and compatibility with each industrial application.
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