All electronic components, from computer chips to high-end power
converters, generate heat, and rejection of this heat is necessary for
their optimum and reliable operation. As electronic designs require
higher power transfer in more compact enclosures, dissipating the heat
load becomes a critical design factor. Many of today's electronic
devices require cooling beyond the capability of standard metallic heat
sinks. Isobar® Heat Pipe
meets this need and is rapidly becoming a mainstream thermal management
tool.
Electronics have traditionally been cooled by fan/heat sink
combinations. However, new high-tech design electronics require higher
power dissipation, with some standard fan/heat sinks no longer meeting
thermal required specifications. The alternative for cooling
electronics: Isobar® Heat Sink. The Isobar Heat Sink
works using natural convection by taking advantage of Isobar® Heat
Pipe's ability to transfer and dissipate heat energy efficiently and
effectively. It offers low thermal resistance and high power
capability, which is very practical given the fact that many
electronics are operating today at or over the 100-watt level.
The Isobar Heat Sink consists of three basic parts:
- Heat input plate, which is fastened to the electronic.
- Isobar® Heat Pipe, which transfers the heat energy from the heat input plate to the fin stack.
- Fin stack, a group of fins that dissipate the heat energy into the air
Isobar Heat Sinks from Acrolab offer the following benefits:
- Ability to transport heat at high rate over considerable
distance with extremely small temperature drop
- Constructional simplicity
- Exceptional design flexibility
- Require no external power) remote cooling fins
- Make efficient use of space
- Low cost and considerable return on investment
Isobar Construction
For operating temperature ranges of 0℃ to 280℃, Isobar chambers
and wick structures are manufactured from pure copper and charged with
purified water as a working fluid. Isobars are typically manufactured
as cylinders or flat shapes as shown in Figure 2. Custom shapes with
different degrees of curvatures are also available. To optimize cooling
efficiency, isobars are also manufactured with different fin array
structures
Wick Structures
The purpose of a wick is to provide:
- The necessary flow passages for the return of the condensed liquid.
- Surface pores at the liquid-vapour interface for the development of the required capillary pumping pressure.
- A heat-flow path between the inner wall of the container and the liquid-vapour interface.
Effective Wick
Generally, an effective wick structure requires small surface pores
for large capillary pressure, large internal pores (in the direction
normal to the liquid flow) for minimal liquid-flow resistance, and an
uninterrupted highly conductive heat-flow path across the wick
thickness for a small temperature drop.
Screen Wick
The most common wick structure is the wrapped-screen wick
(homogeneous wick) shown in Figure 5. The surface pore size of this
wick is inversely proportional to the mesh number, which is defined as
number of pores per inch. The flow resistance for liquid flow can be
controlled by the wrapping tightness. This allows flexibility in
structure. One particular wick type (composite wick structure, made of
two materials) is a tunnel wick. The tunnel wick, shown in Figure 5, is
a pressure primed, high performance wick. Thread grooves are provided
for low heat-flow resistance.
Isobar Cooling Modules
Acrolab has developed high-efficiency Isobar Cooling Modules
capable of dissipating up to 130 wattage load. Isobars carry heat to
the cooling fins where it is dissipated to surrounding air by forced
convection. Cooling Modules offer low thermal resistance and high power
capability. Isobars manufactured by Acrolab are; copper, water, and
copper wick design that operate in any orientation. Acrolab's
experienced staff of dedicated engineers is always ready to assist in
developing specialized solutions to solve specific technical or design
problems in custom products. Just contact us, and your problem is
guaranteed to get the attention it rightfully deserves.
Isobar Cooling Modules
Acrolab has developed high
efficiency Isobar Cooling Modules capable of dissipating up to 120 watt
load with 12℃ temperature drop. Isobars carry heat to the cooling fins
where it is dissipated to surrounding air by forced convection. Cooling
Modules offer low thermal resistance and high power capability. Isobars
manufactured by Acrolab are: copper, water, and copper wick design that
operate in any orientation.
Isobar is a registered trade mark of Acrolab Ltd.
|
