Heat Exchanger - 1

Heat Exchanger – Classification

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Applications :

• Air Conditioners
• Refrigeration
• Natural gas processing
• Petrochemical Plants
• Power Plants
• Radiators (cars, bikes, IC Engines and so on.)
• 99% of Chemical plants

Types :

• Basic Classification:

Recuperative:

• Fluid flows in separate conduits
• Heat transfer from hot fluid to cold fluid across the walls

Plate H-E-X

• Plate & Frame

Fig. 1 .Plate & Frame H-E-X

1. Series of rectangular parallel plates
2. Held firmly with each other.
3. Sealed by gaskets.
4. Hot fluid passes through alternate pairs of plates transferring heat to cold fluid in adjacent spaces.
5. Cleaning easy

• Spiral Plate H-E-X

Fig.2. Spiral Plate

1. Plates are spiral
2. Fluid flows between the channel between plates
3. Compact
4. Easy to clean & turbulence in channel is high, hence used for dirty fluid & slurries.

Tubular H-E-X

• Cluster pipe

Fig.3. Clustered Pipe H-E-X

1. Heat transfer by placing thermally conducting material between tubes.
2. High density, high pressure fluid flows through the core tube at centre.
3. Low density fluid in counter flow direction surrounding the core tube.

• Double Pipe

Fig. 4. Double pipe H-E-X

1. 2 concentric pipes
2. Counter flow gives efficient heat transfer
3. High density, high pressure, viscous fluid passes through the inner pipe.

• Fin Tube H-E-X

Fig. 5. Fin Tube H-E-X

Fig. 6. Finned Tubes

1. No water required, direct cooling by air.
2. Heat transfers from fluid to fin and to the ambient air.
3. Expensive compared to combination of cooling tower and water cooled heat exchanger.

Shell and Tube heat exchanger:

Fig. 7. Shell & Tube H-E-X

1. Used for large heat duties.
2. Mostly used for liquid / liquid heat transfer

Regenerative heat exchanger:

• Single flow channel.
• Flow is over massive solid matrix.
• 'Hot Blow' - when hot fluid transfers heat to the solid matrix.
• 'Cold Blow'- cold fluid now moves over the hot solid matrix to gain heat lost by hot fluid.
• Alternate flow of hot and cold fluid.
• Plastic honeycomb is usually used as regenerative matrix.

• Based on Flow Arrangement:

Parallel Flow

Fig. 8. Parallel Flow

Counter Flow  

Fig. 9. Counter Flow

Cross Flow

Fig. 10. Cross Flow

Multiple Pass Tube heat exchanger.

Fig. 11. Multiple pass Shell & tube heat exchanger

* NOTE: Only the important classifications are provided

* For more extensive study about Heat exchanger classification read this