4 An Application from a Defect—A Friction …
149
It was further reported that very widely used gas to gas, or liquid to gas compact
heat exchangers are made with a surface area density greater than about 700 m
2 /m
3
[43]. Some examples of their applications are heat exchangers used in automotive
vehicles, air conditioning and refrigeration condensers, and evaporators. Oil coolers
used in aerospace, automotive radiators, air heaters, intercoolers of compressors,
etc. are other important areas where these heat exchangers are used extensively.
The compact heat exchangers also frequently find their applications in electronics
cooling, energy recovery systems, and cryogenics.
4.4.2 Conventional Techniques and Limitations
Owing to the various advantages of using the compact heat exchangers with mini
channels, researchers started to venture into different fabrication techniques for
creating continuous cooling channels. Some of the conventional techniques like
drilling, milling, electro-discharge machining (EDM), and advanced techniques like
chemical etching, diffusion bonding, etc. are the techniques most commonly used for
creating cooling channels in heat exchangers. Nevertheless, these techniques have
their limitations.
Drilling, for example, is capable of producing straight hole only, that too up
to a certain depth because of restriction of the length of the drill bit. Milling can
produce non-linear profiled channels, but its capability to produce only open channels adds to its limitations. EDM, on the other hand, can create channels on conductive
materials. The high cost of the set up, the addition of consumables, and the use of
non-flexible tools again limit its application for creating cooling channels. Other
advanced processes like chemical etching have a low material removal rate that
reduces productivity. Selective laser melting is used for fabricating channels, but the
very high cost associated with this process limits its application to the industry level.
Diffusion bonding was also reported to be used for fabricating heat exchangers, but
the process requires primary channel creation by some other techniques. These limitations call for a better manufacturing process that can minimize the disadvantages
of the processes mentioned above.
4.4.3 Potential of FSC Process
FSC has emerged as a new and non-conventional technique by which, in a single
step, continuous and integral channels can be created inside monolithic or dissimilar plates. It is possible to fabricate different shapes of channels by FSC so that
the heat transfer rate can be enhanced. The cooling channels fabricated by FSC
have potential applications in the automotive cooling system, electronic devices and
systems, conformal cooling in the mould industry, and several other domains [48, 49].
149
It was further reported that very widely used gas to gas, or liquid to gas compact
heat exchangers are made with a surface area density greater than about 700 m
2 /m
3
[43]. Some examples of their applications are heat exchangers used in automotive
vehicles, air conditioning and refrigeration condensers, and evaporators. Oil coolers
used in aerospace, automotive radiators, air heaters, intercoolers of compressors,
etc. are other important areas where these heat exchangers are used extensively.
The compact heat exchangers also frequently find their applications in electronics
cooling, energy recovery systems, and cryogenics.
4.4.2 Conventional Techniques and Limitations
Owing to the various advantages of using the compact heat exchangers with mini
channels, researchers started to venture into different fabrication techniques for
creating continuous cooling channels. Some of the conventional techniques like
drilling, milling, electro-discharge machining (EDM), and advanced techniques like
chemical etching, diffusion bonding, etc. are the techniques most commonly used for
creating cooling channels in heat exchangers. Nevertheless, these techniques have
their limitations.
Drilling, for example, is capable of producing straight hole only, that too up
to a certain depth because of restriction of the length of the drill bit. Milling can
produce non-linear profiled channels, but its capability to produce only open channels adds to its limitations. EDM, on the other hand, can create channels on conductive
materials. The high cost of the set up, the addition of consumables, and the use of
non-flexible tools again limit its application for creating cooling channels. Other
advanced processes like chemical etching have a low material removal rate that
reduces productivity. Selective laser melting is used for fabricating channels, but the
very high cost associated with this process limits its application to the industry level.
Diffusion bonding was also reported to be used for fabricating heat exchangers, but
the process requires primary channel creation by some other techniques. These limitations call for a better manufacturing process that can minimize the disadvantages
of the processes mentioned above.
4.4.3 Potential of FSC Process
FSC has emerged as a new and non-conventional technique by which, in a single
step, continuous and integral channels can be created inside monolithic or dissimilar plates. It is possible to fabricate different shapes of channels by FSC so that
the heat transfer rate can be enhanced. The cooling channels fabricated by FSC
have potential applications in the automotive cooling system, electronic devices and
systems, conformal cooling in the mould industry, and several other domains [48, 49].