Vapor Chamber Technology
Overview
A Vapor Chamber is a planer heat pipe that comprises of:
- an evaporator (which makes contact with the area of heat input)
- a sealed vapor chamber containing a working fluid (see below) which transfers heat from the evaporator to the condenser
- a condenser where the transferred heat cools on the condenser surfaces
Two-dimensional heat dissipation.
Vapor Chambers are often confused with heatpipes, and while they share some similarities, they are quite different. Heat pipes remotely conduct the heat from one end to the other in a linear structure whereas vapor chambers evenly spread the dissipated heat.
Comparison Table: Vapor Chamber vs Heat Pipe
| Vapor Chamber | Heat Pipe | |
|---|---|---|
| Application | Dissipates heat directly on the device to be cooled | Moves heat dissipation to another part of the system |
| Form Factor | Top and bottom stamped plates which can take the form of the electronics to be cooled | Small diameter conductive tube (3mm to 10mm) |
| Shapes | Complex shapes due to the stamping process | Round, flattened or formed in any direction. |
| Size | Small (1mm to 5mm thick). Can be formed to the size of the electronics to be cooled | 3mm to 10mm diemeter pipe which can be flattened into oval shapes and can be 500mm long | Mounting To Heat Source | Placement directly on the electronics to be cooled via through holes for attachment | Mostly, indirect contact unless the interface plate machine flat to the profile of the device to be cooled. |
| Heat Source | Direct contact with the heat source, mounting pressure up to 90psi | A base plate makes contact with heat source but heatsink can be remotely positioned ( >150mm) from the heat source connected by the heat pipe. |
| Qmax | T(Thickness)=5mm > 400W, T=3mm > 200W, t=1mm > 60W | ∅5 > 20W, ∅6 > 40W, ∅8 >60W |
| Cost |
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Schematic Diagram
Operation
Per the diagram, during the vapor chamber's operation, the 'heat source' transfers thermal energy to the evaporator side of the vapor chamber. This heat converts the (working) liquid in the sealed chamber into a 'vapor.'
The vapor then cools, via the wicks, on the surfaces of the condenser where the heat will be removed by either convection cooling, forced air convection cooling or liquid cooling.
Once the vapor cools to a liquid, it returns to the evaporator via capillary action and the cycle repeats continuously making the vapor chamber a highly efficient thermal management device.
Samples Of Our Vapor Chamber Capabilities
Vapor Chamber Working Fluid Performance Comparison
The table below depicts the performance characteristics of a variety of working fluids. However, the three most commonly used working fluid in the vast majority of vapor chambers are:
- Water: operating temperature ranges from 30°C to 200°C (readily available and environmentally friendly)
- Methanol: operating temperature range is slightly lower and narrower than water at 10°C to 130°C
- Ammonia: operating temperature ranges from -60°C to 100°C (manufacturing cost is higher due to the toxic nature of ammonia)
| Working Fluid | Melting Point (°C) | Boiling Pt (°C) | Useful Range (°C) | ||
|---|---|---|---|---|---|
| Helium | -272.15 | -268.85 | -271 | to | -269 |
| Nitrogen | -210.05 | -195.75 | -203 | to | -143 |
| Ammonia | -77.65 | -33.25 | -60 | to | -100 |
| Acetone | -93.15 | -56.25 | 0 | to | 120 |
| Methanol | -98.05 | -64.65 | 10 | to | 130 |
| Water | 0 | 100 | 30 | to | 200 |
| Mercury | -38.95 | -356.85 | 250 | to | 650 |
| Sodium | 97.85 | 877.85 | 600 | to | 1200 |
| Lithium | 180.55 | 1341.85 | 1000 | to | 1800 |
| Silver | 960.85 | 2211.85 | 1800 | to | 2300 |
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