**3. Oscillating heat pipe (OHP)**

Oscillating heat pipe (OHP) or pulsating heat pipe (PHP) is a relatively new development that was proposed by Akachi in the field of the heat pipe in cooling technology [11].

OHP is characterized by the following basic features (see **Figure 5**):


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**Figure 5.**

*Types of oscillating heat pipes [12].*

*Heat Pipes Heat Exchanger for HVAC Applications DOI: http://dx.doi.org/10.5772/intechopen.95530*

3.No internal wick structure (simple manufacturing).

**3.1 Operation of oscillating heat pipe (OHP)**

in **Figure 5c** [12].

became from its long capillary tube forming a closed loop. While **Figure 5b** depicts the second type, which is a CLOHP with check valves; it is manufactured from a long capillary pipe with the joining ends to configure a closed loop. The closed-loop heat pipe/check valves contain one or more direction-control oneway check valves in the loop to make the working fluid circulate in one direction only. A closed-end oscillating heat pipe is a third type of heat pipe, which is manufactured from a long capillary tube with closed at both ends, as shown

4.At least one heat-receiving section (evaporator), heat-dissipating section (condenser), and an optional in-between adiabatic section are present [13].

When the evaporator section receives heat, the temperature in the evaporator region increases, which will lead to a rise in the vapor pressure in the channel, and causes the growth of bubbles size in the evaporator section, then bubbles move to the condenser zone by the difference between the pressure of the evaporator and condenser. During the movement of the vapor plug to the condenser section, which is under low temperature, so the condensation process occurs, and the vapor plug collapses. Then, the slug-train in the condenser section is pushed to the adjoining vapor plug, and the liquid slug moves to the evaporator section for nucleation.

*Heat Transfer - Design, Experimentation and Applications*

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**3. Oscillating heat pipe (OHP)**

*Schematic operation of a thermosyphon heat pipe [9].*

*Schematic operation of a conventional heat pipe [9].*

working fluid [13].

technology [11].

**Figure 4.**

**Figure 3.**

Oscillating heat pipe (OHP) or pulsating heat pipe (PHP) is a relatively new development that was proposed by Akachi in the field of the heat pipe in cooling

1.The structure of OHP is manufactured from a bending tube comprised of serpentine channel capillary dimensions with many turns, filled partially by a

2.The OHPs are classified into three main types. **Figure 5a** illustrates the first type of OHP, which is a closed-loop oscillating heat pipe (CLOHP). The name

OHP is characterized by the following basic features (see **Figure 5**):

became from its long capillary tube forming a closed loop. While **Figure 5b** depicts the second type, which is a CLOHP with check valves; it is manufactured from a long capillary pipe with the joining ends to configure a closed loop. The closed-loop heat pipe/check valves contain one or more direction-control oneway check valves in the loop to make the working fluid circulate in one direction only. A closed-end oscillating heat pipe is a third type of heat pipe, which is manufactured from a long capillary tube with closed at both ends, as shown in **Figure 5c** [12].

