Air-Cooled Heat Exchangers – Construction & Standards
Air-cooled heat exchangers are essential components of many industrial and commercial systems. They are designed to transfer heat away from a system by cooling with air. Air-cooled heat exchangers are used in various applications, from cooling air conditioning systems to cooling industrial process fluids and lubricants. They are also used in power plants, oil and gas plants, and commercial buildings. Let’s discuss the construction and standards for air-cooled heat exchangers before you place your order.
Air-Cooled Exchanger Standards
The main standard air-cooled heat exchangers must follow is ASME Code, Sect. VIII Div1 or Div2 regulates all pressure vessels. and any Petrochemical or refinery services typically follow API 661 as an additional specification in addition to their own standards.
Constructing an Air-Cooled Heat Exchanger
Several components must be constructed for every air-cooled heat exchanger, starting with the tube bundle. The tube bundle is the main component of the heat exchanger and is typically made from carbon steel, stainless steel, duplex, copper, or aluminum.
The bundle is then mounted onto the fan deck which is designed to distribute air evenly across the tube bundle. The fan deck is usually made from metal sheets and can be configured in various ways, depending on the design of the unit.
Most air-cooled heat exchangers also require fans, which are mounted either below (forced draft) or on top (induced draft) of the bundle and move air across the tube bundle. The fans are typically made from steel, aluminum, or fibre-reinforced plastic (FRP) and are powered by electric motors.
The fans are connected to motors via belt drives, which are mounted to the structure of the air-cooler bay. Fan and belt guards encase the moving mechanical components for personnel protection. Grease lines permit easy access to lubricate bearings.
Instrumentation is often specified such as thermocouples, averaging RTDs (temperature sensors), and vibration switches or transmitters.
Louvers and actuators may be required for warm-air recirculation, aka winterization. If required, space heaters or heating coils are used to pre-heat the air-cooler bay prior to start-up.
Ladders and platforms are typically required at one or two ends of the air cooler to access header plugs and nozzle flanges.
Often the heat exchanger must have “bug screens” (air filters) to ensure that the air is free of particles and contaminants like poplar fluff before it reaches the tube bundle. The screens are typically made from fine mesh and are designed to capture any debris that may be in the air.
When ordering an air-cooled heat exchanger, make sure to specify the operating conditions and design constraints that the manufacturer needs to consider in addition to the required build standards. This way, you can be sure that your air-cooled heat exchanger will perform as expected in your system and according to local regulations.
Begin Building Your Air-Cooled Heat Exchanger With Altex
Altex is Canada’s leading provider of air-cooled heat exchangers. Our experienced engineers and technicians can help you design and build the perfect air-cooled heat exchanger for your application. Contact us today to learn more about our air-cooled heat exchangers and how we can help you build the right system for your needs and bring your project to life.
FAQ
1. What are air-cooled heat exchangers used for?
Air-cooled heat exchangers are used to remove heat from process fluids and gases without the need for water. They are commonly found in power plants, refineries, petrochemical facilities, and gas processing plants.
2. How do air-cooled heat exchangers work?
They operate by passing hot process fluids and gases through finned tubes while ambient air is forced across the tube bundle using fans. This transfers heat from the fluid to the air.
3. What are the key components of an air-cooled heat exchanger?
Major components include finned tubes, tube bundles, fans, plenum chambers, structural supports, and headers.
4. What construction standards apply to air-cooled heat exchangers?
Typical standards include ASME (American Society of Mechanical Engineers), TEMA (Tubular Exchanger Manufacturers Association), and API (American Petroleum Institute), depending on the application and industry.
5. What materials are used in building air-cooled heat exchangers?
Common materials include carbon steel, stainless steel, aluminum, and copper alloys selected based on temperature, pressure, and corrosion resistance requirements.
6. What factors influence the performance of an air-cooled heat exchanger?
Performance depends on ambient temperature, air velocity, fin configuration, surface area, tube material, and overall design pressure and temperature.
7. How are air-cooled heat exchangers maintained?
Regular maintenance includes cleaning the finned surfaces, inspecting for corrosion or fouling, checking fan alignment and motors, and ensuring structural integrity.
8. What industries typically require custom air-cooled heat exchanger solutions?
Industries such as oil & gas, petrochemical, power generation, mining, and industrial manufacturing often require tailored designs due to varying pressure, temperature, and environmental factors.
9. Why is compliance with ASME and API standards important in heat exchanger manufacturing?
Compliance ensures safety, reliability, and regulatory approval for operation in critical industrial applications. It also facilitates inspection, certification, and long-term equipment performance.
