Heat exchangers are devices that facilitate the exchange of heat between two fluids that are at different temperatures while keeping them from mixing with each other. The primary purpose of a heat exchanger is to either cool down or heat up a fluid, depending on the specific application. Two fluids, a hot fluid and a cold fluid, flow through the heat exchanger in separate channels. The hot fluid transfers heat to the cold fluid through the walls of the heat exchanger channels. The hot fluid exits the heat exchanger at a lower temperature, and the cold fluid exits the heat exchanger at a higher temperature. Parts : Shell: The shell is the outer housing or casing of the heat exchanger. Tubes: The tubes are the inner passages through which one of the fluids flows. Tube sheet: The tube sheet is a flat plate that holds the tubes in place within the shell. Baffles: Baffles are used to direct the flow of fluid through the tubes and to increase the heat transfer surface area. Nozzles: Nozzles are the openings that allow the fluids to enter and exit the heat exchanger.

1. Heat Exchanger
& Its Types
By : Atif Razi

2. Contents
History
Introduction
Working
Materials used for Making
Applications
Classification
Advantages & Disadvantages

3. History of Heat Exchangers
• The history of heat exchangers can be traced back to
ancient times Romans, used hypocaust systems by
passing warm air from furnaces to heat their rooms
and bath through channels under the floors.
• In 1878, the first recorded patent for a plate heat
exchanger was awarded to Albrecht Dracke of
Germany.
• In 1923, Dr. Richard Seligman introduced the first
plate heat exchanger
• In the late 19th century, shell and tube heat
exchangers gained popularity.
• Heat exchanger technology is constantly evolving,
and new and more efficient designs are being
developed all the time.
Albert Dracke Richard Seligman

4. Heat Exchangers
 Heat exchangers are devices that facilitate
the exchange of heat between two fluids
that are at different temperatures while
keeping them from mixing with each other.
 The primary purpose of a heat exchanger
is to either cool down or heat up a fluid,
depending on the specific application.

5. Working of Heat Exchangers
 Two fluids, a hot fluid and a cold fluid, flow through the heat exchanger in separate channels.
 The hot fluid transfers heat to the cold fluid through the walls of the heat exchanger channels.
 The hot fluid exits the heat exchanger at a lower temperature, and the cold fluid exits the heat
exchanger at a higher temperature.
Hot Fluid
Hot Fluid
Cold Fluid
Cold Fluid

6. Parts of a Heat Exchanger

7. Applications
Power Plants HVAC Systems Refrigeration
Systems
Food and
Beverage Industry
Oil and Gas
Industry
Chemical
Processing
Pharmaceutical
industry
Automotive
Industry
Waste Heat
Recovery
Solar Thermal
Systems
Marine Industry Electronics Cooling

8. Materials used for making Heat Exchangers
Titanium Stainless
Steel
Nickel Alloys Copper
Aluminium Carbon Steel Ceramics Plastics &
Polymers

9. Heat
Exchangers
Nature of
Heat
Exchange
Direct
Contact
Indirect
Contact
Flow
Configuration
Parallel Flow
Counter Flow
Cross Flow
Design &
Constructional
Features
Shell & Tube
Multiple Shell
& Tube
Passes
Plate
Concentric
Tubes
Compact
Physical State
of Fluids
Condensers
Evaporators
Classification

10. According to
Nature of Heat
Exchange

11. Direct Contact / Open
Heat Exchangers
 Direct contact heat exchangers are
those in which the two fluids being
exchanged heat are in direct contact
with each other.
 This type of heat exchanger is typically
used for applications where the two
fluids are immiscible, such as oil and
water.

12. Indirect Contact
Heat Exchangers
 Indirect contact heat exchangers
are those in which the two fluids
being exchanged heat are
separated by a solid wall.
 This type of heat exchanger is
typically used for applications
where the two fluids are miscible,
such as water and water.

13. Regenerative / Storage Type
Heat Exchanger
 It is a type of heat exchanger that uses
a storage medium to transfer heat
between two fluid streams.
 In this type, a porous or matrix material
in the shape of a disc referred to as a
heat disc, rotates between two fluid
streams – hot and cold.
 Heat is stored in the matrix material
during one part of the cycle and
released to the other fluid during the
other part of the cycle.

14. Recuperative / Transfer Type
Heat Exchanger
 It is the most common type of heat
exchanger in which two fluid
streams, flow through separate
channels or passages within the
heat exchanger.
 Heat is transferred from the hot fluid
to the cold fluid through the walls of
these passages.

15. According to Flow
Configuration

16. Parallel-Flow
Heat Exchanger
 In this type of heat
exchanger, the two fluid
streams flow in the same
direction.
 The two streams enter at
one end and leave at the
other end.
 Applications : Oil coolers, oil
heaters, water heaters etc.

17. Counter-Flow Heat Exchanger
 In this type of heat exchanger, the two
fluids flow in opposite directions.
 The hot and the cold fluids enter in the
opposite ends.
 Applications : Power Plants, Chemical
Processing Plants, etc.

18. Cross-Flow Heat Exchanger
 In this type, the two fluids
cross one another in
space.
 The two fluids flow
perpendicular to each
other.
 Applications:
Refrigeration Systems,
Automobile Radiators,
etc.

19. According to
Design &
Constructional
Features

20. Shell & Tube Heat Exchanger
 They are the most common type of heat
exchanger.
 They consist of a bundle of tubes enclosed in
a shell.
 One fluid flows through the tubes and the
other fluid flows through the shell.
 Heat is transferred from one fluid to the other
through the walls of the tubes.
 Versatile
 Simple to Design & Build
× Bulky & Expensive

21. Single Shell & Tube Pass Heat Exchanger
 In this type, one fluid flows through
the tubes and the other fluid flows
through the shell once.
 Simplest to design and build
× Less efficient.

22. Multiple Shell & Tube Passes
Heat Exchanger
 In this type, the fluid flows through the
tubes multiple times before exiting the
heat exchanger.
 Multiple shell and tube passes are used
to increase the heat transfer rate
between the two fluids.
 More efficient
× Complex & expensive to design & build

23. Concentric Tube Heat Exchanger
 It consists of two concentric tubes.
 One fluid flows through the inner tube and
the other fluid flows through the outer tube.
 Heat is transferred from one fluid to the
other through the walls of the tubes.
 Simple to design and build
 Well-suited for high-pressure applications
× Not as efficient as shell and tube or plate
heat exchangers.

24. Plate Heat Exchanger
 They consist of a series of thin metal plates
that are stacked together.
 With alternating channels for hot & cold
fluids.
 Heat is transferred from one fluid to the
other through the walls of the plates.
 Versatile
× Not well-suited for high-pressure
applications

25. Compact Heat Exchanger
 They are special purpose heat exchangers
designed to maximize the heat transfer rate
per unit volume.
 They are often used in applications where
space is limited, such as in automotive
radiators and air conditioners.
 Lower capital cost
 Reduced plant size
× Difficult to clean
× Limited operating temperature

26. Compactness
 The compactness and non-compactness of any heat exchanger depend upon area density,
denoted by β (Beta).

 Typically, when
• β > 700 - Compact Heat Exchanger
• β < 700 – Non-Compact Heat Exchanger

27. According to
Physical State of
Fluids

28. Condensers
 A condenser is a heat exchanger that
converts a gas or vapor into a liquid.
 This is done by removing heat from the gas
or vapor.
 Applications :
 Refrigeration
 Air Conditioning
 Power Generation

29. Evaporators
 An evaporator is a heat exchanger that
converts a liquid into a gas or vapor.
 This is done by adding heat to the liquid.
 Applications :
 Refrigeration
 Air Conditioning
 Power Generation

30. Advantages & Disadvantages of Heat
Exchangers
Advantages
Improved
efficiency
Reduced
emissions
Versatility
Temperature
Control
Resource
Conservation
Longevity
Disadvantages