Heat exchangers transfer heat between hot and cold fluids and come in several types defined by the heat exchange process (direct or indirect), fluid flow direction (parallel, counter, or cross flow), and physical state of the fluids (condensers where hot fluid stays at constant temperature or evaporators where cold fluid does). Common heat exchangers include shell and tube designs with one shell and tube pass, and examples are water heaters, oil coolers, refrigeration cooling sections, deaerators, regenerators, and recuperators.

1. HEAT
EXCHANGER
PRASANTA KUMAR BEHERA
School of Mechanical Engineering
April-2017

2. Heat Exchangers and its Types
• Heat exchangers are devices whose primary responsibility is
the transfer of heat from hot fluid to cold fluid.
• Nature of heat exchange process
1. Direct process : ex- Deaerator
2. Indirect process - a) Regenerators , b) Recuperators
(ex. Glass melting furnaces) (ex. Air preheater)

3. • Relative direction of fluid motion
1. Parallel flow 2. Counter flow 3. Cross flow
eEx. Water heaters, oil coolers. Ex. Water heaters. Ex. Cooling section in
refrigeration system

4. • Design and constructional features
Shell and tube
a) One shell pass and one tube pass heat exchanger
• Physical state of fluids
1. Condensers- In condensers the hot fluid remains at constant temperature
and the temperature of cold fluid increases.
2. Evaporators- In this case, the cold fluid temperature remains at constant
temperature and the temperature of hot fluid decreases.

5. References:
• Rajput, R. K. (2014) ‘Heat and Mass transfer’, S. Chand,
Vol.7361, pp.574-580.
• https://www.google.co.in/search?q=Regenerators+heat+excha
nger+images.
• https://www.google.co.in/search?q=Parallel+flow+heat+excha
nger+images

6. Thank you