A heat exchanger is a device that transfers thermal energy between two or more fluids. There are two main types: plate heat exchangers and shell and tube heat exchangers. Plate heat exchangers use metal plates with fluid channels to transfer heat, while shell and tube use tubes bundled inside a cylindrical shell. Both have advantages like efficiency and reliability but also disadvantages such as limited pressure tolerance or difficulty of cleaning. They are widely used to heat or cool fluids in applications like water heating, cooling towers, and industrial processes.

1. Heat Exchanger

2. Topic to be covered
 Introduction
 Construction
 Components
 Working
 Advantages And Disadvantages
 Application And Uses

3. Introduction
 What is Heat Exchanger?
 A device which is used to transfer thermal energy between two or more fluids.
 Classification of heat exchanger
1. Based on transfer process
2. Based on construction
3. Based on flow arrangment

4.  Based on construction
 There are many type of heat exchanger based on construction but
 Mainly we used 2 types of heat exchanger in industrial sector
1. Plate type heat exchanger
2. Shell & Tube heat exchanger

5. Introduction (PHE)
 Plate heat exchanger:-
 A plate heat exchanger is a type of heat exchanger that uses metal plates to
transfer heat between two fluids.
 The plate heat exchanger (PHE) was first invented in 1923 by Dr. Richard Seligman
and revolutionized the systems of indirect cooling and heating of fluids.
 A plate exchanger consists of a series of parallel plates that are placed one above
the other so as to allow the formation of a series of channels for fluids to flow
between them.

6. Construction

7. Components
 Carrying beam: The top component placed between the fixed plate and
supporting column upon which the PHE plates and the pressure plates are
suspended.
 Fixed Plate: The basic component of the PHE frame. The fixed plate is an
unmovable frame plate. Normally, the pipes are connected to this component.
 Support column: A fixed component of a PHE frame to which the carrying beam
and the guiding bar are fixed.
 Pressure Plate: A moveable frame plate suspended at the carrying beam of the
PHE frame. This frame compressed the PHE plates.

8.  Guiding Bar: Component that guides the PHE plates and the pressure plate at the
bottom.
 Tightening Unit: The frame component for compressing the PHE plate pack. It
consists of tightening bolts, tightening nuts and washers.
 Gasket: A gasket is a common term used to describe any seal or grommet that
holds two things together.

9. Working
 The Working principle of plate heat exchanger is
 The fluids flowing through the flow channels on the plates flow through the
gaskets without being mixed with each other and the desired heat transfer is
carried out due to the temperature difference.
 The design of a plate heat exchanger (PHE) comprises several heat transfer plates.
Held by a fixed plate and a loose pressure plate to form a complete unit. Each heat
transfer plate has a gasket arrangement, providing two separate channel systems.
 The arrangement of the gaskets allows through flow in single channels. This
enables the primary and secondary media in a counter-current flow. The mediums
are not mixed because of the gasket design.

10.  Advantages Of Plate heat exchanger
1. Heat transfer precision – improved temperature approach, true counter-current
flow, 80-90% less hold-up volume.
2. Low cost – low capital investment, installation costs, limited maintenance and
operating costs.
3. Greatest reliability – less fouling, stress, wear, and corrosion.
4. Responsible – least energy consumption for most process effect, reduced
cleaning.
5. Easy to expand capacity – adjustable plates on existing frames.

11.  Disadvantages of Plate heat exchanger
1. Poor sealing would case leakage occurrence which will be a replacement hassle.
2. Limited pressure use, generally not more than 1.5MPa.
3. Limited operating temperature due to temperature resistance of the gasket
material.
4. Small flow path, and not suited for gas-to-gas heat exchange or steam
condensation.
5. High blockage occurrence especially with suspended solids in fluids.
6. The flow resistance is larger than the shell and tube.

12.  Application & Uses
1. Water heaters
2. Cooling tower isolation
3. Free cooling
4. Waste heat recovery
5. Heat pump isolation
6. Thermal (ice) storage systems

13. Shell & Tube Heat
Exchanger

14. Introduction
 A shell and tube heat exchanger is a class of heat exchanger designs. It is the most
common type of heat exchanger in oil refineries and other large chemical
processes, and is suited for higher-pressure applications.
 This type of heat exchanger consists of a shell with a bundle of tubes inside it.
 A shell and tube heat exchanger (STHE) is a type of heat exchanging device
constructed using a large cylindrical enclosure, or shell, that has bundles of
perfectly spaced tubing compacted in its interior.

15. Construction

16. Components
 Baffles: Baffles are flow-directing or obstructing vanes or panels used to direct a
flow of liquid or gas. It is used in some household stoves and in some industrial
process vessels (tanks), such as shell and tube heat exchangers.
 Shell: a thin usually spherical layer or surface enclosing a space or surrounding an
object.
 Front Header: A front header, which is also referred to as a stationary header, is the
part from where the fluid enters the tubeside of the exchanger.
 Rear Header: A rear header is a part from where the tubeside fluid leaves the
exchanger or where it is returned to the front header.

17. Working
 The working of a shell and tube heat exchanger is fairly simple. One fluid flows
inside the tubes and the other through the shell. While flowing they exchange the
heats which means the cold fluid gains the heat from the hot fluid and visa versa.

18.  Advantages:-
1. They can be designed and manufactured to bear very high pressures
2. They can be designed and manufactured to bear very high and very low temperatures
3. They have no dimension limit
4. They can be used in all applications
5. Pressure loss is at a minimum and can be maintained at a minimum in line with the process
purpose.
6. They can easily be disassembled and assembled back for maintenance, repair and cleaning
7. Pipe diameter, pipe number, pipe length, pipe pitch and pipe arrangement can be altered. So, the
designs of tube heat exchangers are quite flexible

19.  Disadvantages:-
1. Heat transfer efficiency is less compared to plate type cooler
2. Cleaning and maintenance is difficult since a tube cooler requires enough
clearance at one end to remove the tube nest
3. Capacity of tube cooler cannot be increased.
4. Requires more space in comparison to plate coolers

20.  Uses:-
1. Removal of process heat and feed water preheating
2. Cooling of hydraulic and lube oil
3. Cooling of turbine, compressor, and engine
4. Condensing process vapor or steam
5. Evaporating process liquid or steam

21. Comparison
Plate Heat Exchanger Shell And Tube Heat
Exchanger
Elements use inside the
heat exchanger
Plates Tubes
Pressure Control Control maximum 1.5 Mpa No limit
Heat Transfer Efficiency More Less
Flow Resistance More Less
Space Required Less More