ASPEN HTFS.pdf
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Classification of heat exchangers Page 1
Assignment # 1
Classification of Heat Exchangers
Table of Contents
Heat exchangers can be classified on the basis of: .........................................................................................2
Nature of Heat Exchange Process ................................................................................................................. 2
Flow arrangements .......................................................................................................................................3
According to Construction .............................................................................................................................3
Plate heat exchangers ...................................................................................................................................3
Gasket Plate Heat Exchanger .........................................................................................................................4
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Classification of heat exchangers Page 2
A heat exchanger is a device that is used to transfer thermal energy between two or more fluids at different
temperatures, separated by a boundary or they may be in direct contact.
Heat exchangers are the backbone of industry. Almost every industry needs the heat exchanger. So, it is
necessary to understand the classification of heat exchanger. So, we can classify heat exchangers as follows
Heat exchangers are classifiesd on the basis of:
Nature of Heat Exchange Process (direct contact or indirect contact)
Surface Compactness (compact or non-compact)
Process Function (cooler, heater, evaporator or condensers)
Heat Transfer mechanism , (single phase, multi-phase )
Relative direction of motion of fluids (parallel, counter and cross flows)
Mechanical design of heat exchange surface (tubular, plates and extended surfaces)
Number of Fluids
Physical state of heat exchanging fluids (condensation or evaporation)
How Energy Supplied
Nature of Heat Exchange Process
Indirect Contact Type
Recuperators Regenerative Heat Exchangers
Recuperators
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Classification of heat exchangers Page 3
In an indirect contact heat exchanger, the heat energy is exchanged between hot and cold fluids through a
heat transfer surface, i.e. a wall separating the fluids. The fluids flow simultaneously on either side of a
separating wall, the heat transfer, without mixing or physical contact with each other.
Heat is transfer by convection and conduction.
Examples: Concentric tubes heat exchangers, Extended surfaces heat exchangers, Shell and tube heat
exchangers etc.
Regenerative Heat Exchanger
The hot and cold fluids pass through the same channels in the packing, alternately, both fluids washing the
same surface area. Hence a fluid incoming to a process is heated using the energy contained in the fluid
exiting this process.
Direct Contact Type
Evaporative heat exchangersIn open heat exchanger, the heat transfer between the hot and cold fluids is brought about by their complete
physical mixing, there simultaneous transfer of heat and mass.
For example water cooling tower, jet condensers in steam power plants.
Classification on the basis of Flow arrangements
Single pass Heat Exchangers
A fluid is considered to have made one pass if it flows through a section of the heat exchanger through its full length
and leave through other end. These heat exchanger can be of
Co Current Flow Counter current Flow Cross flow
Classification on the basis of Construction
Concentric tube heat exchangers Extended surface heat exchangers Tubular heat exchangers
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Classification of heat exchangers Page 4
Compact heat exchangersPlate heat exchangers
Has a differences in
1. Types of plates used, and
2. In configurations of plates
3. Gasket Plate Heat Exchanger
Extended Surfaces
When additional metal pieces are attached to the ordinary heat transfer surfaces such as fins or appendages ,
they extend the surface area available for heat transfer
Gasket Plate Heat Exchanger
The plate-and-frame or gasketed plate heat exchanger consists of a number of thin rectangular metal plates
sealed around the edges by gaskets and held together in a frame.