The Most Widely Used Two Phase Technology

For decades, heat pipes were the default two phase device of choice for thermal engineers due largely to the cost difference relative to vapor chambers. They were used both for heat transport, for which they still have an advantage, and for heat spreading, typically using multiple pipes in close proximity to one another. GPU-Heatsink-with-HeatpipeThey can be configured into an almost infinite array of shapes, moving heat from the evaporator to remote locations where it can be more easily cooled. For lower power applications, perhaps requiring only a single, small heat pipe, or those where heat must be effectively transported, heat pipes still maintain dominance.

Celsia’s focuses its efforts on ‘difficult heatsink applications’ requiring multiple heat pipes to transport heat over longer distances or where a complex shape is required and two piece vapor chambers are outside the budget. As with all two phase devices, thickness, wick porosity and type, and amount of working liquid are varied to suit each application’s requirements. In addition to creating specialty square heat pipes for improved thermal conductivity, we are well versed in the design and manufacture of thermosyphons used where the condenser is especially far away from the evaporator.

As with all two phase devices, wall thickness, wick type, wick porosity, vapor space, and amount of working fluid are optimized for each application. Our design engineers have used sintered, mesh and grooved wicks in heat sink designs for a variety of industries.

  • Sintered wick – the most common, and expensive, of the three is a sintered wick design where powdered metal is bonded and hardened to the internal pipe walls. It is most resistant to heat source orientation and gravity as this type of wicking structure has the strongest capillary action.
  • Mesh or Grooved wick – Wick design using either mesh or grooves are considered when the heat source is level with, or above, the condenser and where gravity has no effect (space). The chief benefit of a grooved design is lower cost, while mesh designs can be made extremely thin.

Advantages of Heat Pipes vs. Vapor Chambers

  • Heat transport to a remote fin stack
  • Inexpensive to create complex shapes
  • Lower power applications requiring only a small, single heat pipe
heat-pipes-vapor-pipes

As with all two phase devices, wall thickness, wick type, wick porosity, vapor space, and amount of working fluid are optimized for each application. Our design engineers have used sintered, mesh and grooved wicks in heat sink designs for a variety of industries.

Heat Pipe One Piece VC Two Piece VC
Min/Max Thickness ~2.0mm if flattened >1.0mm >2.0mm
Sizes Diameter: 2-35mm Length: 100-1,000mm Width: 10-100mm Length: 50-500mm Width:50-150mm Length: 50-300mm
Flatness NA 0.001”/” 0.001”/”
Maximum Bending Angle 3x diameter R~10 (inner circle base) No
Shapes: X and Y Direction Yes – Post Production Factory Bending No: Square or Rectangle shape only Yes: Pre-Production
Max Heat Transport Capacity 5 watts @ 2mm 1kw @ 25mm 10watts @ 1mm 500 watts @ 4mm 10watts @ 1mm 500 watts @ 4mm
Allowable Operating Temp. 10 to 150 C 10 to 125 C 10 to 125 C
Storage Temperature -40 to 100 C -40 to 100 C -40 to 100 C
Storage Humidity (%RH) 5~90%RH 5~90%RH 5~90%RH
Life >100,000 hours >100,000 hours >100,000 hours
Through Holes Not Applicable No Yes