Standard Heat Pipes (CCHPs)

Standard heat pipes also known as Constant Conductance Heat Pipes (CCHPs), are the most basic type of heat pipe.  As shown in Figure 1, heat is transferred by the evaporation and condensation of a working fluid:

Heat transfer to the evaporator vaporizes liquid within the wick.

  • Vapor pressure drives fluid to the condenser
  • Heat transfer from the condenser condenses vapor at the wick.
  • Liquid returns to the evaporator by capillary forces generated in the wick

Figure 2 shows two examples of copper water heat pipes used to cool discrete components.  The heat pipes can be bent as necessary between the heat source and sink.  The typical bend radius is greater than 3 times the O.D. of the heat pipe; see Figure 3.

        Figure 1.  Standard Heat Pipe.

curved heat pipesFigure 2.  Heat pipes can be bent into tight curves.

Copper water chip coolingFigure 3 Copper-Water Heat Pipes Used for Electronics Chip Cooling.

 

The benefits of a standard heat pipe include:

  • High Thermal Conductivity (10,000 to 100,000 W/m K)
  • Isothermal
  • Passive
  • Low Cost
  • Shock/Vibration tolerant

There are several limitations for standard heat pipes:

Most heat pipes are not structural components

ACT’s heat pipe calculator can be used to estimate the performance of standard copper-water heat pipes.

Back to Different Types of Heat Pipes…