1. Double pipe heat exchanger
• Two sets of concentric pipes, two connecting tees, and a
return head and a return bend.
• A device whose purpose is the transfer of thermal
energy between two fluids.
• Heat Exchanger-HX
• Common applications: Boilers, Coolers, Condensers,
Evaporators.
• Common design consists of tow fluids separated by a
conducting medium.

2. Classification
 Heat transfer mechanism
 Degree of surface compactness
 Heat transfer type
 Flow arrangement
 Number of passes
 Construction

3. Classification
 Direct contact type: Cooling towers, Spray towers
 Indirect contact type
Cooling tower Spray tower

4. Classification
 Single Pass arrangement
 Multiple pass arrangement

5. Classification
 The choice of a particular flow arrangement depends
upon the required heat exchanger effectiveness, fluid
flow paths, allowable thermal stresses, temperature
levels and other design criteria.
 Heat exchangers may be classified according to their
flow arrangement.
• Parallel-flow
• Counter-flow
• Cross-flow
• Divided-flow
• Split-flow

6. Classification

7. Classification
 The heat exchangers classify based on geometry of
construction are,
• Plate Heat Exchangers
• Extended surface Heat Exchangers
• Tubular Heat Exchangers

8. Classification
 Plate Heat Exchanger
• Limited to below 25 bar and 2500C
• Plate heat exchangers have three main types :
gasketed ,spiral and lamella heat exchangers.
• The most common of the plate-type heat
exchangers is the gasketed plate heat exchanger

9. Classification
Plate type heat exchanger

10. Classification
Spiral heat exchanger

11. Classification

12. Classification
 Plate Heat Exchanger
 Aadvantages
• Plate heat exchangers yield heat transfer rates
three to five times greater than other types of heat
exchangers.
• The design of the plate heat exchanger allows to
add or remove plates to optimize performance, or
to allow for cleaning, service, or maintenance.
• Plate exchangers offer the highest efficiency
mechanism for heat transfer available in industry.

13. Classification
 Plate Heat Exchanger
 Disadvantages
• Plate exchangers are limited when high pressures,
high temperatures, or aggressive fluids are present.
• Because of this problem these type of heat
exchangers have only been used in small, low
pressure applications such as on oil coolers for
engines.

14. Classification
 Extended surface heat exchangers
• Plate fin heat exchanger
• Tube fin heat exchanger
Tube fin exchanger Plate fin exchanger

15. Classification

16. Classification

17. Classification
 Tubular heat exchanger
• Material and design development
• Widely used
• No limit to range of temperatures and pressures
• Two types
1. Double pipe heat exchanger
2. Shell and tube heat exchanger

18. Classification
 Double pipe heat exchanger
They consist of one pipe concentrically located inside a
second larger pipe.
Double pipe exchanger

19. Classification
 Phase change heat exchangers
• Condensers(water cooled, air cooled)
• Reboilers
• Evaporators
Induced draft
Forced draft
Air cooled condenser

20. Classification
 Phase change heat exchangers
Water cooled condenser

21. Classification
Area density: Ratio of heat transfer area to the volume
of heat exchanger
 Compact Heat exchanger
• Area density greater than 700 m2/m3 or 213 ft2/ft3
or hydraulic diameter ≤ ¼ inch for gas stream.
• Area density greater than 400 m2/m3 or 122 ft2/ft3
for liquid stream).
 Non-compact Heat exchanger
• Area density less than 700 m2/m3 for gas stream.
• Area density less than 400 m2/m3 for liquid stream.

22. Classification

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