Air-Cooled Heat Exchangers: Industrial Applications & Benefits
Oil refining, gas compression, and power generation: these processes create so much waste heat that without proper cooling solutions, you’re looking at equipment damage, production slowdowns, and serious safety risks.
However, the reliance on water-based cooling systems is increasingly problematic. Factors like stricter environmental regulations, the escalating costs of water treatment, and the logistical challenges of remote construction have led engineers to adopt a new strategy. This shift has established the air-cooled heat exchanger (ACHE) as a critical component in essential infrastructure, particularly in Canada.
Using ambient air, ACHEs provide a robust, sustainable, and reliable method for process cooling, especially where water is scarce or expensive. For industry leaders, recognizing the value of these systems is key to long-term success.
Understanding Air-Cooled Heat Exchangers
ACHEs represent a fundamental shift from traditional shell-and-tube heat exchangers. Rather than transferring thermal energy between two contained fluids, an ACHE is designed to reject heat from a process fluid directly into the surrounding atmosphere.
- Heat Transfer Process: The cycle begins when the hot process fluid, such as steam, oil, or glycol, flows into and circulates through a specialized bundle of tubes.
- Enhanced Surface Area: Given air’s low heat transfer coefficient, standard bare tubes are inefficient for this task. To solve this, the tubes are equipped with exterior fins (typically aluminum) that are bonded tightly to the surface. These fins dramatically increase the effective surface area, maximizing the contact point for heat dissipation.
- Cooling Mechanism: To drive the exchange, large axial fans designed for continuous industrial duty either force or induce airflow across the finned tube bundle. This forced airflow effectively strips away the thermal energy from the fins, cooling the fluid inside before it returns to the main process loop.
ACHE systems are deployed in two main mechanical configurations:
- Forced Draft: Fans are located beneath the tube bundle, pushing air upward. This configuration is favoured for maintenance ease, as mechanical components (motors, gearboxes) are situated in the cooler intake air stream.
- Induced Draft: Fans are placed on top of the bundle, pulling air through. While mechanicals are exposed to hot exhaust air, this design improves aerodynamics, ensures uniform air distribution, and significantly reduces the risk of hot air recirculation.
The Advantages of Air Cooling Over Water
- Location Flexibility: Water-cooled systems require proximity to a reliable water source. ACHEs eliminate this dependency, allowing facilities, such as those in the remote Canadian oil sands or mining regions, to be built where resources dictate, rather than where water is available.
- Cost and Compliance Reduction: Water management is expensive and complex. It involves chemical treatment to prevent corrosion and discharge monitoring to comply with thermal pollution laws. ACHEs operate in a closed loop; they have no interaction with the local watershed, eliminating the need for intake permits, chemical programs, and discharge monitoring.
Core Industrial Applications
Oil and Gas Production
In the rugged upstream and midstream sectors, ACHEs, often called aerial coolers, are indispensable for natural gas compression stations. As gas is pressurized for transport, immense heat is generated that must be dissipated to protect pipeline infrastructure. These units cool both the compressed gas and the compressor lubricating oils, supporting continuous operation at remote sites where water access, winter maintenance, and rapid response are limited.
Petrochemical Refining
Air-cooled units are essential in refineries. They provide forced-air cooling to condense process vapours back into the liquid phase for downstream handling and storage. Because chemical processes require exact thermal parameters for safety and product quality, operators utilize Variable Frequency Drives (VFDs) on the fans. This technology allows airflow to be ramped up or down instantly, ensuring precise temperature control even as ambient weather shifts from the heat of the day to the cool of the night.
Power Generation
The power sector relies on a massive variation of this technology known as the air-cooled condenser (ACC). In a steam turbine cycle, exhaust steam must be condensed back into liquid water to return to the boiler; ACCs achieve this using only ambient air. This closed-loop system drastically reduces a plant’s water footprint and eliminates thermal pollution, making power generation feasible in arid regions or areas with strict water conservation laws.
Engineering for Extreme Canadian Climates
Operating in North America presents a unique challenge: the vast temperature swing from scorching summers (35°C) to deep winters (-40°C). Standard equipment often fails under these conditions.
Specialized cold-weather engineering is critical. Altex designs units that incorporate:
- Automated Louvres: Used to close off airflow and retain necessary heat during cold periods.
- Recirculation Chambers: Mix warm exhaust air with cold intake air.
These features prevent viscosity increases in glycol and heavy hydrocarbon service, reducing the risk of elevated pressure drop and unplanned shutdowns.
Altex: Leaders in ACHE Manufacturing and Service
We don’t just manufacture equipment; we support it through its entire operational life:
- Refurbishment Services: As a one-stop shop for heat transfer equipment, we offer cost-effective retubing, repairs, and re-rating services to extend the life of your assets. Our dedicated maintenance facilities allow us to handle even the most complex projects, which we affectionately call the “Big and Ugly”, including large-diameter, high-pressure units with challenging metallurgies. By replacing tube bundles while preserving existing steel structures and fans, we maximize value without compromising performance.
- Field Services: From our humble beginnings with “four guys in a truck,” our field division has grown to deploy over 1,000 experts during peak turnaround seasons. Our field teams go beyond diagnosing vibration, fan drive issues, tube bundle degradation, and thermal performance shortfalls by executing comprehensive turnaround services, including boiler repairs, controlled bolting, and tube bundle handling.
Contact Altex today for air-cooled heat exchangers and more!
In an industry where downtime costs thousands per minute, your cooling infrastructure is paramount. Partner with us to ensure your assets are built for performance and supported for a lifetime.
Contact Altex online today or call (780) 468-6862 to discuss your specific thermal duty requirements with our engineering team and secure a proven, high-efficiency solution.
