RESEARCH AND DEVELOPMENT

Thermistance is the first Indian start-up completely devoted to develop advanced passive cooling technologies and its commercialization. Our world class team is continuously working to develop innovative micro and miniature cooling devices. We are also developing our research and development centre in Pune.

Heat Pipe Integrated With Heat Sink

A heat sink with integrated heat pipes is another efficient method for thermal management. In this design, heat pipes are embedded within or attached to a finned heat sink structure. The heat pipes rapidly transfer heat away from the electronic component to the fins by using the evaporation and condensation of a working fluid inside the pipes. The fins, with their large surface area, then dissipate the heat into the surrounding air, often assisted by forced air from a fan. This combination significantly enhances the thermal conductivity compared to traditional solid metal heat sinks.

Structure of Heat Pipe Based Heat Sink

Key Components:

  1. Heat Pipe (Core):
    • Material: Typically copper or aluminum for high thermal conductivity.
    • Function:The heat pipe acts as the conduit for heat transfer. It consists of an evaporator (heat absorption zone), a vapor channel, and a condenser (heat dissipation zone).
    • Fluid:A working fluid (e.g., water, ammonia, or refrigerants) is sealed within the heat pipe. The fluid undergoes phase change (from liquid to vapor and vice versa) to transfer heat.
  1. Heat Sink:
    • Material:Usually aluminum or copper for effective heat dissipation.
    • Function:The heat sink is attached to the condenser section of the heat pipe. It provides a large surface area to dissipate the heat from the fluid (via convection to the surrounding air).
    • Design:Often features fins or a fin array to enhance heat dissipation.
  1. Fittings/End Caps:
    • Function:Seal the heat pipe and maintain the working fluid's pressure.
    • Design:End caps are typically brazed or welded to prevent fluid leakage.


Principles of Heat Pipe Based Heat Sink

The principle behind heat sink-based heat pipes is the latent heat transfer capability of the working fluid. The heat pipe utilizes a phase change process to efficiently transfer heat:

  1. Evaporation: Heat is absorbed from the heat source, causing the working fluid inside the heat pipe to vaporize at the evaporator section.
  1. Vapor Transport: The vaporized fluid rises through the vapor channel due to the low pressure created in the evaporator, assisted by capillary forces in the heat pipe’s wick structure.
  1. Condensation: The hot vapor reaches the condenser section, which is attached to a heat sink. The vapor loses heat to the heat sink and condenses back into liquid form.
  1. Liquid Return: The condensed liquid is then returned to the evaporator via gravity, capillary action, or a return wick, completing the cycle.

Working of Heat Pipe Based Heat Sink

Heat Absorption: The heat source (e.g., a CPU or power electronics) transfers heat to the evaporator section of the heat pipe.

Phase Change: The heat absorbed causes the working fluid inside the heat pipe to evaporate, converting the liquid into vapor.

Vapor Flow: The vapor travels along the vapor channel to the condenser section. The heat pipe maintains low resistance to the vapor flow.

Heat Dissipation: At the condenser, the vapor condenses back to liquid form. This phase change releases the latent heat, which is then carried away by the heat sink’s large surface area

Liquid Return: The condensed fluid is then returned to the evaporator section by capillary action in the wick or gravity, and the cycle repeats.

Advantages of Heat Pipe Based Heat Sink

1. Efficient Heat Transfer: Heat pipes provide high thermal conductivity (100x that of copper), transferring heat quickly from the source to the heat sink.

2. Compact Design: Heat sink-based heat pipes are more compact compared to other cooling methods like traditional air cooling or standalone heat sinks.

3. Passive Cooling: No external power is required (e.g., no fans), reducing energy consumption and system noise.

4. High Performance in Small Spaces: They can be integrated into compact electronic devices, efficiently cooling high-power components in confined spaces.

5. Scalable and Flexible: Heat pipes are scalable for various sizes and power requirements, from small electronics to large industrial applications.

6. Low Maintenance: As passive systems, they require minimal maintenance and have no moving parts, improving reliability.

7. Uniform Cooling: The use of heat sinks with heat pipes provides more uniform heat distribution, reducing hotspots.

8. Longevity: Heat pipes have a long operational life due to their lack of moving parts and efficient cooling properties.

Applications of Heat Pipe Based Heat Sink

Heat sink-based heat pipes are used in various industries and applications requiring effective cooling, including:
1. Electronics Cooling:



2. Telecommunications:

3. LED Lighting:

4. Renewable Energy:

5. Automotive:

6. Space Applications:

key components:

  1. Heat Pipe (Core):
    • Material: Typically copper or aluminum for high thermal conductivity.
    • Function:The heat pipe acts as the conduit for heat transfer. It consists of an evaporator (heat absorption zone), a vapor channel, and a condenser (heat dissipation zone).
    • Fluid:A working fluid (e.g., water, ammonia, or refrigerants) is sealed within the heat pipe. The fluid undergoes phase change (from liquid to vapor and vice versa) to transfer heat.
  1. Heat Sink:
    • Material:Usually aluminum or copper for effective heat dissipation.
    • Function:The heat sink is attached to the condenser section of the heat pipe. It provides a large surface area to dissipate the heat from the fluid (via convection to the surrounding air).
    • Design:Often features fins or a fin array to enhance heat dissipation.
  1. Fittings/End Caps:
    • Function:Seal the heat pipe and maintain the working fluid's pressure.
    • Design:End caps are typically brazed or welded to prevent fluid leakage.



The principle behind heat sink-based heat pipes is the latent heat transfer capability of the working fluid. The heat pipe utilizes a phase change process to efficiently transfer heat:

  1. Evaporation: Heat is absorbed from the heat source, causing the working fluid inside the heat pipe to vaporize at the evaporator section.
  1. Vapor Transport: The vaporized fluid rises through the vapor channel due to the low pressure created in the evaporator, assisted by capillary forces in the heat pipe’s wick structure.
  1. Condensation: The hot vapor reaches the condenser section, which is attached to a heat sink. The vapor loses heat to the heat sink and condenses back into liquid form.
  1. Liquid Return: The condensed liquid is then returned to the evaporator via gravity, capillary action, or a return wick, completing the cycle.



Heat Absorption: The heat source (e.g., a CPU or power electronics) transfers heat to the evaporator section of the heat pipe.

Phase Change: The heat absorbed causes the working fluid inside the heat pipe to evaporate, converting the liquid into vapor.

Vapor Flow: The vapor travels along the vapor channel to the condenser section. The heat pipe maintains low resistance to the vapor flow.

Heat Dissipation: At the condenser, the vapor condenses back to liquid form. This phase change releases the latent heat, which is then carried away by the heat sink’s large surface area

Liquid Return: The condensed fluid is then returned to the evaporator section by capillary action in the wick or gravity, and the cycle repeats.

1. Efficient Heat Transfer: Heat pipes provide high thermal conductivity (100x that of copper), transferring heat quickly from the source to the heat sink.

2. Compact Design: Heat sink-based heat pipes are more compact compared to other cooling methods like traditional air cooling or standalone heat sinks.

3. Passive Cooling: No external power is required (e.g., no fans), reducing energy consumption and system noise.

4. High Performance in Small Spaces: They can be integrated into compact electronic devices, efficiently cooling high-power components in confined spaces.

5. Scalable and Flexible: Heat pipes are scalable for various sizes and power requirements, from small electronics to large industrial applications.

6. Low Maintenance: As passive systems, they require minimal maintenance and have no moving parts, improving reliability.

7. Uniform Cooling: The use of heat sinks with heat pipes provides more uniform heat distribution, reducing hotspots.

8. Longevity: Heat pipes have a long operational life due to their lack of moving parts and efficient cooling properties.

Heat sink-based heat pipes are used in various industries and applications requiring effective cooling, including:
1. Electronics Cooling:

  • CPUs/GPUs in computers: Heat pipes help keep processor temperatures within safe limits.
  • Power electronics: Heat sinks with integrated heat pipes manage heat from high-power components.


2. Telecommunications:
  • Cooling for base stations, transmitters, and high-power amplifiers that generate large amounts of heat.


3. LED Lighting:
  • High-power LEDs require efficient cooling to prevent overheating and improve lifespan.


4. Renewable Energy:
  • Used in solar thermal systems to dissipate heat from photovoltaic (PV) panels or thermal receivers.


5. Automotive:
  • EV battery cooling: Heat pipes in battery management systems prevent thermal degradation in lithium-ion batteries.
  • Electric vehicle motors and inverters: Provides thermal management in compact spaces.


6. Space Applications:
  • Satellites and spacecraft use heat pipes for temperature control, as conventional cooling methods (like fans) are ineffective in zero gravity.