Computer Technology
Miniature Heat Pipes
The widespread and fast-paced adoption of notebook computers in the
home, workplace and on-the-road owes part of its success to space shuttle
and space station technology.
Thermacore Inc. of Lancaster, Pennsylvania has been associated with
Goddard Space Flight Center since 1989. NASA Small Business Innovation
Research (SBIR) contracts with Thermacore fostered company work on devices
tagged "heat pipes" for space applications.
A heat pipe moves heat from spot-to-spot with little loss in temperature.
The heat pipe employs a two-phase process in which a liquid is evaporated
inside the pipe by heat input at one end. The resulting vapor is condensed
back into the liquid by heat removal at the pipe's other end. The condensate
is then returned to the evaporator by capillary action in a wick.
To control the extreme temperature ranges in space, heat pipes are vitally
important to spacecraft. Of additional benefit is that heat pipes do not
suffer from the wear and tear of moving parts. They are, therefore, exceptionally
reliable.
As Thermacore's Chairman, G. Yale Eastman, points out: "All heat
pipes are not created equal." Using its own funds, the firm employed
knowledge gained from SBIR research to solve a challenge in the commercial
marketplace of notebook computers.
The problem was to maintain an 8-watt central processing unit (CPU)--the
real brains of a computerat less than 90 degrees Celsius in a notebook
computer using no power, with very little space available and without using
forced convection. Using a fan to cool this electronic circuitry required
far too much battery power. That would reduce the useful operating time
of the notebook.
| NASA heat pipe technology used in spacecraft
to keep hardware and critical electronics cool has found its way into notebook
computers. Tiny heat pipes are in wide use to cool the main central processor
chip. |
Thermacore's answer was in the design of a powder metal wick that transfers
CPU heat from a tightly confined spot to an area near available air flow.
The Thermacore heat pipe technology permits a notebook computer to be operated
in any position, even upside down, without loss of performance.
Miniature heat pipe technology has successfully been applied, such as
in Pentium® Processor notebook computers. In desktop computers, higher-powered
CPU chips or multi-chip modules means higher-powered power supplies, more
memory and other power-hungry components. Each of these components dissipates
heat. Thermacore expects its heat pipes to accommodate these computers
as well.
Given the high volume of computer manufacturing, the cost of heat pipes
has been reduced significantly, quite often providing an economical solution
to many cooling applications. Thermacore has used company funds to develop
the fabrication processes needed and to build the factory required for
mass production of miniature heat pipe technology. Production rates have
already exceeded 5,000 units per day.
Cellular telephones, camcorders, and other hand-held electronics are
foreseeable applications for heat pipes, predicts the company.
By advancing commercial use of federally-sponsored research, Thermacore
received in October 1996 the SBIR Technology of the Year Award in the Computer/Electronics
category.
® Pentium is a registered trademark of Intel Corporation.
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