Based on its recent research on the wearable energy harvesters market, Frost
+ Sullivan presents Holst Centre and imec
with the 2009 European Frost + Sullivan Award for Technology Innovation for
its wearable electrocardiograph energy harvesting solution, which provides tens
of microwatts of energy per square centimetre for modules with 3x4 cm2 dimensions.
Due to its convenience of use, self powering, and low maintenance, this has
opened the way for a wide range of commercial and personal solutions. The European
open-innovation R+D centres Holst Centre and imec achieved this result within
their R+D program on micropower generation and storage.
Recently, Holst Centre and imec developed miniaturized health monitoring systems,
which consume heat naturally dissipated from the human body in order to operate.
While wearable devices that operate using the body’s heat have been in
use for several years, small thermoelectric energy generators have so far proven
their capability to power only small personal devices such as watches without
needing an external power source. The unique device developed by Holst Centre
and imec is the result of clever design of a thermal harvester, matched specifically
to a human body, as well as a large reduction of the power consumption of the
electronics. The thermal harvester is made of a thermoelectric material, in
this case bismuth telluride, that converts human body heat into electric current.
Once this device is placed close to the body, it generates electricity that
is further accumulated in an energy storage system. The electricity capacitor
subsequently powers the autonomous wearable electrocardiography (ECG) system
and a radio which transmits the ECG signal real-time to a base station. Thanks
to clever optimization, the power consumption of the electronics has been largely
reduced. The thickness of the system components does not exceed 6.5 mm and can
be easily integrated into fabric. Once installed, the system requires no technical
maintenance.
“The personal devices, which couldn’t be made portable due to their
large sizes or high power requirements can now be developed in the form of easy
to wear and care gadgets,” says Frost + Sullivan Research Analyst
Krzysztof Grzybowski. “This approach is valid for monitoring systems and
related personal low-power appliances that could be integrated in clothes, e.g
watches. On the other hand, devices like mobile phones currently still use too
much power to be powered by body heat.
Holst Centre and imec’s demonstrated energy harvesting solution provides
tens of microwatts of energy per square centimetre of the skin for modules with
3x4 cm2 dimensions. In this specific application, the energy harvesting module
efficiency was sufficient to operate the wearable ECG using fourteen units integrated
in a shirt and occupying less than 1.5 per cent of its total area. The device
operation was tested in indoor and outdoor conditions with outdoor clothes worn
on and off. During energy harvesting, the power management unit of the presented
system uses the ASIC converter to charge two 2.4V batteries, which are powering
the second stage DC/DC converter supplying the ECG unit. In all cases, the system
performance was sufficient to operate the ECG.
Further, the whole unit is fortified against the mechanical stress that would
accidentally destroy the fragile thermopiles of the energy harvester. The shock
protection, made of thermally isolating material, is placed between the radiator
and the hot end of the device (exposed to the source of a heat). It was found
that this protection facilitates even washing the device in laundry with a drying
cycle of 1,000 rpms. Interestingly, the developed prototype is service-free
for its entire life and user activity is only limited to the need of wearing
it. Once placed close to the body the device starts itself and monitors the
patient’s health.
“Most personal devices still consume large amounts of energy that cannot
be provided by currently available energy harvesting solutions,” notes
Krzysztof Grzybowski. “However, increasing efficiencies of energy harvesters,
such as the system developed by Holst Centre and imec for health monitoring
systems, combined with a further decrease of power consumption of the electronic
elements could enable the fabrication of a wide range of self sustainable personal
solutions in the future.”
Holst Centre and imec will continue to miniaturize self-powered health monitoring
devices such as this one through decreasing their power consumption. Maintenance-free
devices, self-powered for their entire service life such as the demonstrated
electrocardiograph in a shirt, allow for efficient and easy monitoring of human
health, which was not possible in the past. In recognition of this unique wearable
energy harvesting technology based on a unique design platform, Frost +
Sullivan is proud to present Holst Centre and imec with the 2009 European Technology
Innovation Award in the wearable energy harvesters market.
Each year, Frost + Sullivan presents this award to a company that has carried
out new research, which has resulted in innovations that have or are expected
to bring significant contributions to the industry in terms of adoption, change,
and competitive posture. The award recognizes the quality and depth of a company’s
research and development program as well as the vision and risk-taking that
enabled it to undertake such an endeavour.
Frost + Sullivan Best Practices Awards recognize companies in a variety
of regional and global markets for demonstrating outstanding achievement and
superior performance in areas such as leadership, technological innovation,
customer service, and strategic product development. Industry analysts compare
market participants and measure performance through in-depth interviews, analysis,
and extensive secondary research in order to identify best practices in the
industry.