Brazed Way

A compact brazed heat exchanger is constructed as a plate package of corrugated channel plates like this one.

A compact brazed heat exchanger is an efficient way to transfer heat from one medium to another. This type of heat exchanger consists of many corrugated plates that are combined to create complex channels through which a hot medium and a cold medium can be distributed. The mediums come into close proximity without mixing inside the unit, on either side of the corrugated plate, and energy is transferred from one to the other as they flow side by side.

In principle, a compact brazed heat exchanger is constructed as a plate package of corrugated channel plates between front and rear cover-plate packages. The cover plate packages consist of sealing plates, blind rings and cover plates. During the vacuum-brazing process, a brazed joint is formed at every contact point between the base and the filler material.

Fluids can pass through the heat exchanger in different ways. Because a brazed heat exchanger is modular, it is easy to change the channel plate material or add or remove a number of channel plates. This modularity makes the system extremely flexible and the number of possible configurations infinite.

Because of this flexibility, the list of applications that operate efficiently with compact brazed heat exchangers is a long one: beverage coolers, cogeneration systems, deionized water systems, hydraulic oil coolers, lube oil coolers, onboard coolers, air dryers, chillers, cascade heat pumps and refrigeration systems.

Simulation is one of the most important stages in the development of new and existing compact brazed heat exchangers. The ability to evaluate different plate patterns by simulating flow rate and directions offers great opportunity for improved functionality.

Simulation for Improved Efficiency

Simulation is one of the most important stages in the development of new and existing compact brazed heat exchangers. The ability to evaluate different plate patterns directly on the computer, by simulating flow rates and directions, offers opportunities for shorter time-to-volume and improved functionality for new products. Extensive research and development, combined with effective use of computational fluid dynamics (CFD) simulations have made it possible to create brazed heat exchangers with improved heat transfer and lower pressure drop.

CFD is a tool that can improve the level of heat transfer in the brazed heat exchanger because it allows the flow in its channels to be simulated using 3-D models. Simulation makes it possible for a large number of design changes to be calculated and evaluated quickly. Low flow areas can be identified and eliminated, which leads to a lower risk of damage from freezing and fouling and gives more efficient heat transfer. Complementing theoretical values with laboratory tests gives a comprehensive basis for developing new products and product revisions. These CFD results can be verified empirically, giving them a high level of confidence. The result is heat exchangers with ideal flow across the channel plates and minimal pressure drop in the port.

With simulation, all parameters can be varied freely, allowing millions of combinations to be calculated to obtain the optimal design for a brazed heat exchanger.

Another technology that enhances the performance of compact brazed heat exchangers is corner passage pattern (CPP), a pressed plate pattern that directs the cooling medium in an ideal movement around the port. CPP opens up a larger area for heat transfer in the port area. The cooling medium is spread over a larger area, with significant heat transfer gains.

Take a look at your process to determine if this is the best type of heat exchanger for you.