The Complete Guide to Heat Exchangers: Types, Design, and Applications

• A heat exchanger is a device that transfers heat between two fluids without mixing them, essential in countless industrial processes.

• The five main types: shell-and-tube, plate, air-cooled, plate-fin, and scraped surface, are used based on fluid type, pressure, and space.

• Material selection (e.g., copper alloys, stainless steel, titanium) impacts corrosion resistance, durability, and thermal efficiency.

• Routine maintenance following ASME and TEMA guidelines prevents fouling, leaks, and performance loss over time.

Heat exchangers are critical components across countless industrial processes, like marine propulsion, oil refining, air conditioning, and power generation. They ensure efficient thermal energy transfer between fluids, often preventing system failures, minimizing energy waste, and maintaining temperature control in vital machinery.

This guide explores everything engineers, procurement managers, and maintenance professionals need to know about heat exchangers: types, materials, thermal performance, industry-specific applications, and how to optimize their use.

A heat exchanger is a device designed to transfer heat between two or more fluids (liquids, vapors, or gases) without them mixing. One fluid typically flows inside tubes or plates, while the other flows around them, allowing heat to pass via conduction and convection.

According to the American Society of Mechanical Engineers (ASME), the efficiency and safety of heat exchangers are essential to meeting thermal processing standards across energy, chemical, and manufacturing sectors.

Heat exchangers are indispensable in:

• Marine engineering: for engine cooling and desalination
  

• Petrochemical refining: for heating, cooling, and distillation columns
  

• Power generation: in condensers and steam cycles
  

• HVAC systems: regulating building and equipment temperatures

• Renewable energy: including thermal storage systems

According to MarketsandMarkets, the global heat exchanger market is projected to reach over $28 billion by 2028, driven by sustainability goals and energy efficiency regulations.

One of the most common types, these consist of a bundle of tubes housed within a cylindrical shell. One fluid flows inside the tubes, and another flows outside the tubes but inside the shell.

• Standards: Governed by TEMA (Tubular Exchanger Manufacturers Association)

• Applications: Oil refineries, chemical processing, marine propulsion

• Pros: High pressure and temperature resistance, modular

• Cons: Larger footprint

These use thin, corrugated plates stacked together to create parallel flow channels.

• Applications: Food processing, HVAC, pharmaceuticals

• Pros: Compact size, easy maintenance

• Cons: Lower pressure tolerance

Instead of using water or another liquid, these exchangers use air (often assisted by fans) to cool the process fluid.

• Applications: Remote locations, power plants, gas pipelines

• Pros: Water-free cooling

• Cons: Larger size, performance varies with ambient air temperature

These compact exchangers use finned surfaces to increase surface area and improve efficiency.

• Applications: Aerospace, cryogenic, compact energy systems

• Pros: High surface area, excellent for small spaces

• Cons: Costly, more sensitive to fouling

Used for high-viscosity fluids, these feature rotating blades to prevent fouling and ensure consistent thermal contact.

• Applications: Food, cosmetics, sludge treatment

Efficient heat exchanger design involves balancing:

• Heat transfer coefficient (U)

• Surface area (A)

• Temperature gradient (∆T)

• Pressure drop (ΔP)

ASHRAE guidelines recommend optimizing for turbulence and minimizing fouling to improve efficiency. Advanced computational fluid dynamics (CFD) is often used to simulate flow behavior and thermal exchange before prototyping.

Materials significantly affect heat exchanger longevity and performance. Key materials include:

• Copper Alloys: Admiralty Brass, CuNi 90/10 and 70/30 – excellent for seawater resistance (source: Copper Development Association)

• Stainless Steel: Resists scaling and oxidation, good for hygiene-critical applications

• Titanium: High corrosion resistance in harsh environments, including chlorinated water

Corrosion Considerations:

• Galvanic corrosion between dissimilar metals

• Biofouling in marine systems

• Scaling and deposition in high-mineral-content systems
  

Routine cleaning and inspections are critical. Common issues include:

• Fouling: Accumulation of debris or scale

• Leaks: Caused by corrosion or gasket failure

• Pressure drops: Indicating blockages or tube damage

Recommended practices (per ASME and TEMA):

• Regular chemical or mechanical cleaning

• Eddy current testing for tube integrity

• Gasket replacement during scheduled downtime

In marine environments, shell-and-tube and plate exchangers are used for:

• Engine cooling
  

• Freshwater generation (evaporators)

• Ballast water treatment
  

Exchangers play key roles in:

• Distillation columns
  

• Heat recovery units (HRUs)

• LNG liquefaction
  

API (American Petroleum Institute) sets key exchanger standards in these environments.

Used in:

• Steam condensers
  

• Cooling towers
  

• Combined-cycle gas turbine systems

IEEE and ASME standards govern performance and safety.

Plate and finned-tube exchangers are used in:

• Chillers
  

• Heat pumps
  

• Air handling units

Modern heat exchanger design is shifting toward:

• Compact geometries for modular plants
  

• Waste heat recovery integration
  

• Additive manufacturing for fin structures

• Smart sensors for condition-based monitoring
  

EU EcoDesign and US DOE regulations are pushing for increased thermal efficiency and reduced emissions.

From copper alloys to titanium, from cryogenics to HVAC, heat exchangers are critical across sectors. Choosing the right type and maintaining it properly means ensuring energy efficiency, safety, and process reliability.

Admiralty Industries is proud to support global manufacturers and engineers with high-performance, corrosion-resistant tubing and components for all major heat exchanger systems and solutions.

ASME. Boiler & Pressure Vessel Code. ASME, 2024, https://www.asme.org.

TEMA. TEMA Standards for Shell-and-Tube Heat Exchangers. Tubular Exchanger Manufacturers Association, 2024, https://www.tema.org.

Copper Development Association. Copper Alloys in Heat Exchangers. Copper.org, 2024, https://www.copper.org.

American Petroleum Institute. API Heat Exchanger Standards. API, 2024, https://www.api.org.

MarketsandMarkets. Heat Exchangers Market by Type, Material, End-Use Industry – Global Forecast to 2028. MarketsandMarkets, 2024, https://www.marketsandmarkets.com/Market-Reports/heat-exchanger-market-750.html.

IEEE. Heat Exchanger Design and Performance Guidelines. IEEE Xplore Digital Library, 2024, https://ieeexplore.ieee.org.

European Commission. EcoDesign Directive: Heat Exchangers and Energy Efficiency. European Commission, 2024, https://ec.europa.eu/energy/topics/energy-efficiency/ecodesign_en.

ASHRAE. ASHRAE Handbook—Fundamentals. American Society of Heating, Refrigerating and Air-Conditioning Engineers, 2021, https://www.ashrae.org.