The efficient, sustainable, and reliable execution of modern industrial processes is directly dependent on the quality, efficiency, and compatibility of the equipment used. In this context, the selection of the right type of heat exchanger is crucial for achieving energy management, cost control, and long-term performance goals in process engineering. Since heat transfer is one of the fundamental building blocks of many industrial applications, its effective implementation also contributes to gaining a competitive advantage for businesses.
One of the most effective solutions that emerges at this point is brazed heat exchangers. This type of exchanger stands out with its compact size, high heat transfer capacities, low maintenance requirements, and long service life advantages, and is widely used in many areas, especially in oil cooling, HVAC systems, renewable energy projects, and the food and beverage industry. Brazed heat exchangers also offer effective solutions even in confined spaces with high pressure and temperature resistance, maximizing system efficiency.
Especially due to their energy efficiency, environmentally friendly structure, and economical service life, brazed heat exchangers fully comply with today’s understanding of sustainable industry. In this article, we will comprehensively discuss the technical structures, engineering features, advantages, applications, and how they compare with other types of heat exchangers. Additionally, we will demonstrate the practical effectiveness of this type of exchanger with examples from real field applications.
Brazed heat exchangers (Brazed Plate Heat Exchangers – BPHE) are one of the most efficient and compact solutions in modern heat transfer technologies. These systems are produced by vacuum brazing thin stainless steel plates, which are assembled together to provide high thermal performance, with metals such as copper or nickel in special applications at high temperatures. The monoblock structure formed after the brazing process guarantees both the durability and long service life of the system.
In the internal structure of the exchanger, fluids are directed to flow either in parallel or crosswise between the plates. This allows liquids to pass through different surfaces of the plates without mixing, enabling effective heat exchange. Thanks to the special corrugated patterns on the plate surfaces, turbulent flow is achieved, which maximizes the heat transfer coefficient. Thus, a high amount of energy can be transferred with a relatively small volume.
Brazed heat exchangers do not use gaskets, which eliminates the risk of chemical leakage and allows safe operation under high pressure and temperature. This feature makes them ideal for heavy industrial conditions, confined spaces, closed-loop cooling systems, and processes requiring high hygiene.
Moreover, the AISI 316 class stainless steel used in the production of brazed heat exchangers offers high corrosion resistance against acidic and basic environments. This allows them to be safely used with different fluids. With advantages such as energy efficiency, low maintenance needs, and long service life, brazed heat exchangers are used as a fundamental heat transfer solution in a wide variety of sectors today, from HVAC systems to the food industry, and from energy facilities to automotive manufacturing.
Technical Specifications of Brazed Heat Exchangers
Plate Material:
The plates used in brazed heat exchangers are generally made of AISI 316 quality stainless steel. This material is known for its high corrosion resistance and maintains its durability even in harsh chemical environments. It can be safely used in systems that work with seawater, acidic liquids, and abrasive fluids. Additionally, due to the high mechanical strength of AISI 316, the risk of plate deformation is quite low.
Brazing Material:
The joining material used between the plates is mostly copper with 99% purity. This material completely integrates the plates with each other through the brazing process performed in a vacuum environment. Copper, being a metal with high thermal conductivity, provides both structural durability and supports heat transfer performance. Additionally, nickel-brazed models are preferred, especially in environments with high chloride content. Since nickel exhibits superior resistance to corrosion, it offers long service life in processes with aggressive fluids.
Operating Temperature:
Brazed heat exchangers can operate safely over a wide temperature range. Generally, they can perform between -196°C and +200°C. This allows them to be used in both cryogenic applications and processes requiring high temperatures. It is recommended to support operations close to freezing and boiling points with special control systems.
Operating Pressure:
A standard brazed heat exchanger is designed to withstand a maximum operating pressure of 30 bar. The test pressure applied during the production process usually goes up to 45 bar. This high pressure tolerance guarantees that the exchangers operate safely and leak-proof. This feature provides significant advantages, especially in closed-loop systems or high-flow installations.
Fluid Compatibility:
Brazed heat exchangers can work compatibly with water, thermal oil, glycol mixtures, ammonia, ethanol, acetic acid, and some light chemicals. Their wide range of chemical compatibility makes them versatile for use in different sectors. However, if they are to be used with fluids containing high particulate matter or high viscosity, it is recommended to support them with appropriate filtration systems.
Corrosion Resistance:
The internal structure of brazed heat exchangers provides optimum performance in systems operating in the pH range of 7–10. Additionally, long service life is possible in systems where low chloride levels (e.g., <700 ppm chloride ion), sulfate, ammonia, and iron ratios are controlled. In systems that come into contact with corrosive chemicals, material selection and protective measures should be planned accordingly.
Heat Transfer Surface:
The internal plate structure of brazed heat exchangers is optimized with special corrugated patterns. These patterns allow the fluid to flow turbulently. Turbulent flow increases the heat transfer coefficient, thereby enhancing the overall efficiency of the exchanger. At the same time, this structure reduces the accumulation of deposits and scale on the plate surfaces, thus minimizing maintenance requirements.
Operating Principle of Brazed Heat Exchangers
Brazed heat exchangers are fundamentally a heat transfer system where two different fluids exchange heat through high-efficiency plates without coming into contact with each other. These systems are generally designed to operate based on the counterflow principle. The counterflow principle allows hot and cold fluids to move in opposite directions, maximizing heat transfer. This optimizes the temperature difference at the inlet and outlet of the exchanger, ensuring high energy efficiency.
The stainless steel plates inside the exchanger are arranged in a specific sequence and geometry, tightly bonded together with copper brazing applied in a vacuum environment. Each plate acts as a thermal bridge between two adjacent fluids. The special corrugated patterns (waveforms) on the plate surface allow the fluid to progress not in a straight line but with continuous direction changes, creating turbulent flow. This turbulent structure generates a much higher heat transfer coefficient compared to laminar flow and also reduces the risk of clogging by minimizing the accumulation of contaminants.
Brazed heat exchangers also show high resistance to sudden temperature changes. Thanks to this heat shock-resistant structure, the system maintains stable performance even under prolonged and challenging conditions. Their compact design allows for maximum heat transfer surface area with minimal volume. This provides significant advantages, especially in applications where space is limited—such as boiler rooms, HVAC systems, and packaged heating/cooling units.
Additionally, their gasket-free structure eliminates the risk of internal leakage. This makes the system a safer, quieter, and low-maintenance solution. Brazed heat exchangers are also preferred in processes that require very precise temperature control between fluids; because heat transfer is quite precise and rapid. This high responsiveness offers excellent heat management, especially in systems under dynamic loads.
Advantages of Brazed Heat Exchangers
1. Compact Design:
Brazed heat exchangers occupy minimal space within the system due to their small size. This feature provides a significant advantage, especially in industrial and commercial applications where space constraints are a concern. Their compact structure allows for a simpler and more organized system installation. Additionally, they save labor and cost during transportation and assembly processes.
2. High Heat Transfer Efficiency:
The special corrugated patterns of the internal plates ensure turbulent flow between the liquids. This allows for much more surface contact compared to laminar flow, thus enabling faster heat transfer. Therefore, brazed heat exchangers can achieve a higher rate of energy transfer in a much shorter time compared to traditional exchangers.
3. No Maintenance Required:
The gasket-free design of brazed heat exchangers is one of their biggest advantages. Since maintenance-requiring elements such as gasket wear or deformation are eliminated, businesses can use these products continuously for long periods. The extension of maintenance intervals is a significant advantage in terms of production continuity and operational efficiency.
4. Durability:
Brazed heat exchangers are designed to operate smoothly in high-pressure and