This presentation showed the method of enhancement in heat exchanger

1. HEAT EXCHANGERS
ENHANCEMENT
PREPARED BY: ASSIST. LECT. HUSSEIN T. DHAIBAN
REF. & AIR-COND. / DIJLIAH UNIVERSITY
4 / 2018NOV. /

2. OVERVIEW:
• DEFINE OF THE HEAT EXCHANGERS
• TYPES OF THE HEAT EXCHANGERS
• APPLICATIONS
• AIM OF ENHANCEMENT
• HEAT EXCHANGERS ENHANCEMENT TECHNIQUES
• MIND MAP FOR HEAT EXCHANGER ENHANCEMENT
• EXAMPLES

3. 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. in heat
exchangers, there are usually no external heat and work
interactions. heat exchangers differ from mixing chambers in that
they do not allow the two fluids involved to mix.

4. Classification of Heat Exchangers
Base of
Classification
Contacting
Technique
Construction
Surface
compactness
Flow
Arrangement

5. Fig. 1: Classification of heat exchanger

6. Fig. 2 : Some types of heat exchangers
(a) Shell & Tube – (b) Double pipe – (c) Fin – (d) Plate – (e) parallel and counter flow in DPEX
(a)
(b)
(c)
(d)
(e)

7. Applications
Heat Exchangers Are Commonly Used In :
1- Process Industries.
2- Heating And Cooling In Evaporator.
3- Thermal Power Plant.
4- Air Conditioning Equipment , Refrigerators.
5- Radiators For Space Vehicles And Automobiles.

8. Aim of Enhancement
Enhanced heat transfer surfaces can be used for three purposes:
(1) to make heat exchanger compact(small in size) in order to reduce
their overall volume, and their cost.
(2) to minimize the pumping power required for a given heat transfer
process.
(3) to increase the over all heat transfer coefficient U value of the
heat exchanger, that mean increasing in efficiency of process &
system.

9. To study the enhancement of heat exchangers must be known to increase the heat
transfer rate from the following:
U = f ( h , K , f , A)
• h= to increase (h) must be use the method of enhancement.
• K= to increase (k) must be change in pipe material.
• f= to increase (f) must be change in roughness surface .
• A = to increase (a) must be change in design area.
Heat Exchangers Enhancement Techniques

10. Continue
A. Active method
The active method involves external power input for the enhancement in heat transfer; for examples :
- Magnetic field to disturb the light seeded particles in a flowing stream
- Jet impingement , suction
- Vibration method
B. Passive method
The Passive heat transfer augmentation methods does not need any external power input. In the convective
heat transfer one of the ways to enhance heat transfer rate is to increase the effective surface area and
residence time of the heat transfer fluids.
- Treated Surfaces: pits, cavities or scratches
- Inserts: twisted tape, wire coils, ribs, baffles, plates, helical screw insert, mesh inserts, convergent – divergent
conical rings, conical rings
- Extended Surfaces: extended surfaces or fins
C. Compound method
When any two or more techniques i.e. passive and active may be employed simultaneously to enhance the heat
transfer of any device.

11. Why Passive Techniques?
 These techniques generally use simple surface or geometrical modifications to
the flow channel by incorporating inserts or additional devices
 It does not need any external power input.
 Insert manufacturing process is simple and these techniques can be easily
employed in an existing heat exchanger.
 Passive insert configuration can be selected according to the heat exchanger
working condition.
 It can be used in design of compact heat exchangers.

12. Mind Map for Heat Exchanger Enhancement

13. Examples of The Types of Twisted

14. Examples of The
Types of Helical
Examples of The
Types of Baffles

15. NANOTECHNOLOGY
The production of particles with sizes on the order of nanometers
(nanoparticles) can be achieved with heat exchanger. Nanofluid
(nanoparticles fluid suspensions) is described this new class of
nanotechnology based heat transfer fluids that exhibit thermal
properties superior to those of their host fluids or conventional particle
fluid suspension. As a consequence, the idea of suspending these
nanoparticles in a base liquid for improving thermal conductivity. CPU
for personal computer is one of nano applications.

16. THANK YOU FOR YOUR ATTENTION !
Think beyond/ can you find a new way to enhance heat
exchanger ??