A heat pipe heat exchanger is a simple device which is made use of to transfer heat from one location to another, using an evaporation-condensation cycle. Heat pipes are referred to as the "superconductors" of heat due to their fast transfer capability with low heat loss.

1. DEPARTMENT OF MECHANICAL ENGINEERING
Seminar on
“ HEAT PIPE”
BY SONAM PALJOR PES1201702403

2. CONTENTS
 Introduction
 What is a Heat Pipe Works
 Working principle
 components of heat pipe
 Types of heat pipe
 Advantages
 Disadvantages
 Application
 Conclusion
 References

3. WHAT IS A HEAT PIPE?
 A heat pipe heat exchanger is a simple device which is made use of to transfer
heat from one location to another, using an evaporation-condensation cycle.
 Heat pipes are referred to as the "superconductors" of heat due to their fast
transfer capability with low heat loss.

4. WORKING PRINCIPLE
 The heat input region of the heat pipe is called evaporator, the cooling region is
called condenser.
 In between the evaporator and condenser regions, there may be an adiabatic
region

5. WORKING
 The first consideration in the identification of the working
fluid is the operating vapor temperature range.
 Within the approximate temperature band, several possible
working fluids may exist and a variety of characteristics
must be examined in order to determine the most
acceptable of these fluids for the application considered.

6. COMPONENTS OF HEAT PIPE
 Container
 Working fluid
 Wick or Capillary structure

7. CONTAINER
The function of the container is to isolate the working fluid from the outside
environment.
Selection of the container material depends on many factors. These are as
follows:
 Compatibility (both with working fluid and external environment)
 Strength to weight ratio
 Thermal conductivity
 Ease of fabrication, including welding, machineability and ductility
 Porosity
 Wettability

8. CONTAINER MATERIALS
Of the many materials available for the container, three are by far the most
common in use—name copper, aluminum, and stainless steel.
Copper is eminently satisfactory for heat pipes
 operating between 0–200◦C in applications such as electronics cooling.
While commercially pure copper tube is suitable, the oxygen-free high
conductivity type is preferable.
Like aluminum and stainless steel, the material is readily available and can be
obtained in a wide variety of diameters and wall thicknesses in its tubular
form.

9. WORKING FLUID
The prime requirements are:
 compatibility with wick and wall material
 Good thermal stability
 wettability of wick and wall materials
 vapor pressure not too high or low over the operating temperature range
 high latent heat
 high thermal conductivity
 low liquid and vapor viscosities
 high surface tension
 acceptable freezing or pour point

10. EXAMPLES OF WORKING FLUID
MEDIUM
MELTING PT.
(° C )
BOILING PT. AT ATM.
PRESSURE (° C)
USEFUL RANGE
(° C)
Helium
Ammonia
Water
Silver
- 271
- 78
0
960
- 261
- 33
100
2212
-271 to -269
-60 to 100
30 to 200
1800 to 2300

11. WICK STRUCTURE
 It is a porous structure made of materials like steel, aluminium, nickel or
copper in various ranges of pore sizes.
 The prime purpose of the wick is to generate capillary pressure to transport
the working fluid from the condenser to the evaporator.
 It must also be able to distribute the liquid around the evaporator section to
any area where heat is likely to be received by the heat pipe.

12.  Wicks are fabricated using metal foams, and more particularly felts, the latter
being more frequently used. By varying the pressure on the felt during
assembly, various pore sizes can be produce.
 The maximum capillary head generated by a wick increases with decrease in
pore size.
 The wick permeability increases with increasing pore size.
 Another feature of the wick, which must be optimized, is its thickness. The heat
transport capability of the heat pipe is raised by increasing the wick thickness.
 Other necessary properties of the wick are compatibility with the working fluid
and wettability.

13. WICK WORKING PHENOMENON

14. WICK DESIGN
Two main types of wicks: homogeneous and composite.
Homogeneous
made from one type of material or machining technique. Tend to have either high
capillary pressure and low permeability or the other way around. Simple to design,
manufacture, and install .
Composite
made of a combination of several types or porosities of materials and/or
configurations. Capillary pumping and axial fluid transport are handled
independently . Tend to have a higher capillary limit than homogeneous wicks but
cost more.

16. TYPES OF HEAT PIPES
 Thermosyphon
 Leading edge
 Rotating and revolving
 Cryogenic pumped loop heat pipe
 Flat Plate
 Micro heat pipes
 Variable conductance
 Capillary pumped loop heat pipe

17. ADVANTAGES
May reduce or eliminate the need fir reheat,
Allow cost effective manner to accommodate new ventilation
standards,
Requires no mechanical or electrical input,
Are virtually maintenance free,
Provide lower operating costs,
Last a very long time,
Are environmentally safe.

18. DISADVANTAGES
 Adds to the first cost and to the fan power to overcome its resistance.
 Requires that the two air streams be adjacent to each other.
 Requires that the air streams must be relatively clean and may require
filtration.

19. APPLICATIONS
 Electronics cooling
 Aerospace
 Heat exchangers
 Engines and automotive industry
 Human body temperature control
LAPTOP HEAT PIPE SOLUTION
HEAT PIPES USED IN PROCESSOR

20. CONCLUSIONS
 Heat pipe is a thermal super conductor under certain heat transfer condition they
can transfer the heat energy 100 times more than available best conductive
materials, because of negligible temp. Gradient exist in heat pipe.
 The heat pipe has compactness, light weight, reversible in operation and high
thermal flux handling capability makes heat pipe to use new modern era and in
many wide variety application to overcome critical heat dissipation problem.

21.  Ravibabu P Rajshekar.K Rohit Kumar Gupta.K, ‘Heat Pipes –Integrated Circuit
Coolers’ Proceedings of the 7th IASME / WSEAS International Conference on
HEA TRANSFER, THERMAL ENGINEERING and ENVIRONMENT (HTE '09)
 Sri Jaiandran A/LMunusamy Heat pipes in electronic packaging - January 2006
 Chi, S.W., "Heat Pipe Theory and Practice: A Source Book," Hemisphere Publishing
Corporation, 1976.
 R.J. Goldstein *, W.E. Ibele, S.V. Patankar, T.W. Simon, T.H. Kuehn, P.J. Strykowski,
K.K. Tamma, J.V.R. Heberlein, J.H. Davidson, J. Bischof, F.A. Kulacki, U.
Kortshagen S. Garrick, V. Srinivasan, K. Ghosh, R. Mittal Heat transfer—A review
of 2004 literature
REFERENCES

22. THANK YOU…!